Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Navy - Military - Battleships: => Topic started by: Backerther on October 05, 2024, 10:59:39 am
-
Hi all, and Allen A
Are you watching here, Allen ? PT-109 again here!
I have started the autumn project for this year with this pla-model fast boat because I got this in incredibly cheap price.!!
In addition to the above, I like this class of PT boats in its hull shape as well as its proper and sufficient size in storage, transportation and sailing on our lake. O0 :-)) Above all, this is an easy to assemble pla-model kit with potential performance
to run very well on the lake as a fast boat. O0 :D :-)) Moreover, this kit is not so detailed in many points that is also
convenient and attractive for me to build to get it to run in fast speed, which is quite different from Italeri kits of MTBs. {-) :-))
This kit I got this time was the third one to assemble.
The kit seems so old as to be produced in the first batch around 1980? judging from the tea colored instruction manuals which are like the ancient documents like the original Bible ..???!!!! {-) {-) {-)
-
Oh, it's very rare to have found these mal-injection moulded parts nowadays.... O0
Yes, this kit may be truly exceptionally old one judging from these imperfect moulding parts.... %% %%
So many years seem possibly to have passed since moulded...partly discolored or stained.
Or excess plastics came out of the mould at the branches...
But they are not large problems for assembling, :-)) needless to say. It is just out of curiosity in modern times. !! :D {-) {-)
-
The hull shape is generally well moulded for the old kit. :D
It's completely Ok for an experimental use as the starting base. :-))
I like this Elco 80 type of hull for a RC fast boat. O0 I'd expect it to be a good fast runner with new style on our
boating lake as my second PT-109 had performed as I expected it to be. :-)) :-)) %%
-
Take a look at the following pics. Yes! indeed this hull is necessary and sufficient enough to be a good runner even on the large
lake. :-)) :-)) :-)) This is no more a toy like size of pla- model hull, isn't it.? O0 O0 O0 ;D
Well then, what shall I do with this large hull next...?? {-) {-) {-) Shall I make a fast boat again in different style to be able to sail on the large lake?? %) :-) %%
-
Now, I have gotten into actual work toward an experimental MTB PT-109(JP).!! Success or not success..??? O0 :D %) 8) {-)
First of all, I have to secure the water-tight work around the edge of the deck.
The freeboard of this hull is sooo low that the water-tight structure must be indispensable for this fast lake-going boat.!!
Especially on the rough water as seen in pic 4.... O0 O0 ;)
I set 5mm square base around the deck cutout to attach the water-tight rubber seal on the base.
-
This time I glued the rubber seals on the base to prevent the water ingress.
Slow but steady to proceed to the final success on the lake..?? {-)
-
I deliberately studied where to cut out of the transom to install the drive system.
And I drew the lines around the transom after intensive study which is very important to install the drive system neatly. O0
At last, I cut it out roughly as in the pics below. I can't go back to the original shape of the nice hull line any more.... O0 :embarrassed:
There is no road ahead except proceeding to a successful result of this experimental project. :embarrassed: ;)
-
And I scraped some convex portions completely which were the very obstacles to set the drive system.
Pics1-2;original shapes
Pics3-4;Scraped completely roughly, but it's quite Ok,!
Now, it's ready to accept the drive system.! :-))
-
At last, water jet thrusters have come on in my hands. !!! :-))
At a glance, they look powerful enough to get my PT-109(JP) out onto the lake at an appealing and convincing speed to me as a water jet boat. O0
I checked roughly the units to know what sort of structure the water jet pump was consisted of....as I do not know much about it.
In this sense, on going project is really a kind of big challenge and an experiment for me to build a water jet boat from a conventional pla-model boat. :-))
Yes, my third PT-109 is going to the water jet style MTB from a conventional screw propeller type MTB.
This third PT-109(JP) will look so old in the form, but will be new in the propulsion system. {-) {-) {-)
Just like a T-type Ford car born in the very beginning of the 20th century with a new hybrid engine in modern times...??? {-)
-
And I set the Mabuchi motors in the jet thrusters to check if they really work well as the powerful sources for the modernised
PT-109(JP) for so short a time. I repeated it several times having intervals of some minutes between the tests.
Because the motors cannot be water-cooled yet at this stage.
Fundamentally OK as brushed motors....but,..but ...OK...but...I decided to go with these motors for the time being... O0 %)
Reasonable and final conclusion if its decision is right is postponed to the bathtub test in the near future. O0
-
Interesting Kiyo........ :o
...why have the cooling water tube inlet side for the Right motor closest to the motor endplate [with the carbon brushes], but the cooling water tube inlet side for the Left motor closest to the motor endpate [with the outputshaft]?
What am I missing?
Derek
-
Derek,
Thank you for your comment and a good question on the cooling tube layout.
Unless they are set like that, cooling water coil outlets are not able to face outward each other to drain the water. :embarrassed:
This time I bought the cooling water coils which have been available as only one type, unlike clockwise or counter-clock wise
as seen in screw prop blades.
I am intending to reproduce powerful screw prop wakes as in the pic by water jet nozzles, if possible... :embarrassed:
Ongoing PT-109(JP) prototype jet boat is so unique for me to build and sail on the lake since I haven't done so far
in my long RC boat/ ship career. :D
-
I made a couple of gaskets for the jet pump thrusters roughly and applied them for the pumps for trial fitting.
It seemed fundamentally OK and will set them as they are as final before installing in the hull. O0
-
Well, it's about the time to install the jet pump units into the hull bottom, isn't it..?? O0
Before that, unnecessary parts of the hull have to be cut them out...!
This is a pla-model boat so that it's so easy to do the above which is one of the reasons I am in favor for the pla-model kits. :embarrassed: %) Needless to say, I do like the wooden Rc boats,too !! {-)
There is nothing but has demerits or merits in this world, isn't it.!? O0 {-) :embarrassed: ok2 :-))
I cut the unnecessary parts out roughly and filled the stern tube holes with epoxy.
-
I have come up here with installing the pump units actually on the hull bottom for trail fitting. O0 :-))
Everything is going on and on at so so basis.! :-)) {-)
The modernised PT-109 is forming at her power plant.!!? :embarrassed: ♪～♬～♬～(^^♪
-
And I made a new transom as shown below roughly. ♫～♬～♩～♪～(^^♪ :-))
-
That looks nice Kiyo, keep up the good work! :-)) :police: ;)
-
Hi Arno,
A great thanks for your comment and interest in my PT-109 jet boat project. !! :-))
I imagine it must be so interesting to see the jet boat sail on our local lake at speed with the old-fashioned style of PT-109.
I have thought to discriminate the jet boat from the conventional type of PT-109 by adding (JP) meaning "jet propelled" after the PT-109 like "PT-109(JP)". O0 :embarrassed:
-
Hi Kiyo,
my Shannon class lifeboat also has two jet drives, my first boat with that propulsion system. In the bathtub it looked promising, I hope it will be the same on the water. At the moment I still need to spray the hull and deck, waiting for appropriate weather…. What make are your jet drives? Mine are Kehrer ones from Germany, bigger than yours as my build is 1/12 th scale.
Regards,
Arno
-
First of all, I did not know that your highly detailed Shannon is powered by jet drive system at all due to my poor knowledge
concerning life boat itself. This kind of RC boat is not generally popular here in Japan.
In this sense, I was a bit surprised to know your Shannon is equipped with TWO jet drives.... O0 :D
I have thought for long the boat was driven by conventional screw propellers..... :o :o :o
The life boat is all Greek to me, as I am a Japanese!! {-) {-) {-) {-) %% %% %% O0 O0 O0
By the way, I know the manufacturer of Kehrer which is so famous and distinguished in this world unlike mine made in China.
Instead, mine is so inexpensive with the quality of so so level... {-) {-)
The water has come through the impeller tube into the hull slightly in early stage and shut it out completely by O rings in the bathtub test for three 3minute tests.
The thrusting force seems fundamentally Ok for me as far as the boat is used for a scale pla- model MTB.!!!
Unless satisfied with the trial on the lake, it's so easy to replace with much powerful motors and lipo battery.
Draining of cooling water is also OK and good for static test of hull.!!! :-)) :-)) :-))
The motor did not get hot, but a bit warm for 3 minutes test. O0
This PT-109(JP) could be really and possibly called a very "jet boat" from the pics...???? {-) {-) {-)
-
Thanks for the information, all looks promising to me. I am sure you will make a success out of it :-))
-
Thank you so much, Arno.!! :-))
I'm also looking forward to your superb Shannon to have an awesome success on the water in the very near future.!!! :-)) :-))
Kiyo
-
After checking if the nozzles are neatly and correctly fittted to the main body of jet pumps through the transom via gaskets, I permanently glued and renewed the transom so securely to cope with imaginably and continuously hard vibration of motors to get the boat sail fast on the water.!!! O0 :D This boat is intended and expected actually to run fast like/as a jet RC pla-model MTB.!! O0 :embarrassed: %)
-
Linkage work around jet pump units and steering servo was "cheerfully" done completely as it was so easy to do.! :-))
-
An easy and happy work is going on and on as seen below.!! :embarrassed: :D
Water cooling tubes and a water proof bag around steering rod were set at this stage..!
I can't wait to see the jet propulsion test in the bathtub. I wonder cooling water should drain well enough..?? O0
I wonder the jet propulsion should come out of the nozzles powerfully or powerlessly..?? O0 :embarrassed: :o
This is one of the most important elements leading to a great success in this experiment project used with PT-109 MTB. O0
-
Kiyo, what material did you use to get the bellow watertight at the transom? Is that black silicone? I am asking as I still have to do that on my build. Yours is looking good :-))
-
Arno to be contacted later
so sorry
-
Hi Arno,
I'm awfully sorry to have kept you waiting so long due to my autumn trip to Okinawa located about 1250 miles southwest
of Tokyo where I live. It was about 30 degrees C still now in the region and nice place to stay for autumn vacation. :-))
By the way, the material I am using for watertight purpose around the steering rod is truly black silicone rubber originally intended for dust covers for shock absorbers of my 1/8 RC Jeep.
I have diverted the item to the watertight part this time. :-)) :-)) :-))
But as you may know, similar item for the watertight purpose of the RC boats is available easily in the internet dealers. O0
-
Hi Kiyo, many thanks for your reply. I think we have quite the same approach. I will use black silicone in order to fill the gap between transom and bellow.
A trip to sunny Osaka, that really sounds promising, a nice vacation in order to gain new energy for your build {-)
-
Yes, indeed. but I spent the vacation in Okinawa (southern islands of Japan) and not in Osaka...Arno.! :embarrassed: %%
By the way, I made an intensive calking procedure all around the jet drive thrusters to prevent the water ingress as seen below
and finally set the radio gears in the hull only for testing the jet drive function and cooling water sucking function as well as water ingress. Especially, last two functions are fatally important for a jet thrusting fast boat like this MTB to be sailed on the lake. O0 ;D
Pic1 is before calking.
Pic7 is what I have used for calking which is one of major manufacturers of Japan.
Last pic is the location of Okinawa where is very far away from Tokyo as if it was a foreign country in its distance. %%
-
Many thanks for your reply, Kiyo! And please excuse me for not writing Okinawa, I sent the post after a hard day‘s work yesterday <:(
-
Oh, No, Arno. Never mind at all. !!!
Even I do not have much geographical knowledge of your country..... <:( {-) O0
from Kiyo in Okinawa, semitropical and heavenly islands of this world! :D {-)
-
Simply wonderful :-)) :-)) :-))
-
Thanks Arno for your always friendly comment.!! :-))
I tested the jet pump units in the bathtub with these setup and a good impression for a fast boat fundamentally.
However I don't know and am not confident that this result should be really Ok for a fast runner to sail on our lake...
As the initial impression of the jet flow, it looked sufficiently OK! but...but...but....??? something a bit unsatisfactory to me when I imagine the boat is run as a fast boat on the lake......If this boat was run with a brushless motor, it could produce much more
powerful jet BLAST-like water flow...?? Well then, change the brushed motors to brushless motors for potentially advantageous power source for the jet boat.! O0 :D
Pic1 shows Tamiya DMD by which I tried so-called tank type steering with the present brushed motors.
Worked well except on max. continuous speed run over around 1minute. Auto-cut function did a good job.!!
-
I am using brushless outrunners, Kiyo. No need for water cooling in my case. After the bath tub test I changed from 2S to 3S Lipo batteries.
I have ordered super x from an ebay seller in Tokyo :-)) I like that it is without solvent and will give it a try.
-
I placed an order of inrunner brushless motors for my application to be water-cooled.
The motor is 4000KV and 50000RPM max with no-load so that water-cooling is absolutely indispensable.
Therefore, I think 2S lipo will do sufficiently for my jet propulsion MTB perhaps.
3S lipo will cause the MTB to fly a bit over water-surface just like a flying fish..??? {-) %% :D :o
"Cemedine Super X" is really nice for a water-tight application and I have been using this one for many years.
Pics below are the brief test with 2S lipo at 2/3 throttle. I was feared to increase more speed due to its jet flow... :D :o :o O0
Prior to this test, I used 3S lipo....Oh my Goodness! It's like really the jet "blast" against bathtub wall.
But the motor was kept cold throughout the test thanks to water-cooling.! O0 :-))
This time I made water-cooling coils by myself to meet my requirement to get the motor cool intensively.
This is because the coil became longer(number of turns, around 7) around the motor can than those being sold in the market.
-
While waiting for the brushless motors to arrive, I set a pair of bilge keels as shown below.
These bilge keels actually and prominently worked very well in my second PT-109 on the large lake at high speed quick turns. :-)) :-)) :-))
-
A practical RC boat does need a good serviceability and I cut the deck into two for maximum and full access into the hull
as seen below.
"No good serviceability, no good RC boat sailing" is my basis {-) to enjoy RC boating on the spot and in my work shop.!! O0
The front deck is supposed to fix to the hull, needless to say.
-
I decided not to glue these three "hatches" to the deck for regular checking of steering servo and motor couplings before sailing
at the boating spot. The gun mount and engine ventilators ? are positioned conveniently for this RC jet model maintenance,
aren't they? {-) O0 :-))
-
The brushless motors arrived here at last and I made a couple of hand-wound water cooling coils to attach to the motors.
So far as I made the coils by myself, I made them symmetrical in their inlet and outlet directions each other unlike ready -made ones having been sold in the hobby market. O0 ;D I wonder non-famous and cheap Chinese-made motors should really work
properly in the hull to sail on the lake for over 5 minutes at speed in each time of sailing...??? {:-{ :D O0
These two motors never work properly for over several minutes at MTB like speed without water cooling, and will surely be blown off unless properly water-cooled. O0 :D <:(
Overall length of each coil will reach about 21" which will be possibly enough to cool the brushless motor.! :-)) :-))
-
Kiyo....
I think the mirror reverse inlet/outlet of your wound cooling coil will pay benefits in optimizing/minimizing cooling tube length/mass...[and that's how full size manufacturers would have constructed them] :-))
I understand your natural concern optimizing the heat transfer [cooling] especially considering the use of higher output brushless motors
When you think about the physical design, we have single point contact between the spiral OD of the individual spiral tube set and the motor outer shell.......all of the heat generated by the motor that does not touch this single spiral point in the tube coil, is wasted heating the air between the next coils in the tube set [in this case, air is a poor conductor and thermally inefficient]
A relatively inexpensive trial would be to use a thermally conductive paste spread fully into the coiled spiral airspace to the inner tube coil set, before you slide the tube set over the motor shell
These products are designed for the electronics industry to conduct heat from components to lower the operational temperature O0
A trial using such a paste would only add maybe 10 to 15 grammes extra weight to the vessel displacement, and maybe $20 total for two motor coils
Let me know what you think
Derek
-----------
https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwjW5qu2mNSJAxWMN4MDHVawJXkYABAQGgJzZg&ae=2&aspm=1&co=1&ase=2&gclid=Cj0KCQiA88a5BhDPARIsAFj595h_jvefX4PmNZlRDJKtFvOTXfuwH953ZE0SvzoIw3nMz-mDLmiCJ4kaAi1eEALw_wcB&ohost=www.google.com&cid=CAESVeD2Qpa4KpxVUV4qBTy_Kw3FPfEPU4YHedQY-gdNEMLSaIagtFn_hiZEgg56mWT7iI7lQtl3Uiib1zIIBPNROkcVfkWk1Oyb90y1PT8ZqOd3iBfD5RQ&sig=AOD64_1PNv_F99OpBRHvr5Z6cKTmhHTLdQ&ctype=5&q=&nis=4&ved=2ahUKEwjVmKa2mNSJAxUY1jgGHRCXDQwQ9aACKAB6BAgFECc&adurl= (https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwjW5qu2mNSJAxWMN4MDHVawJXkYABAQGgJzZg&ae=2&aspm=1&co=1&ase=2&gclid=Cj0KCQiA88a5BhDPARIsAFj595h_jvefX4PmNZlRDJKtFvOTXfuwH953ZE0SvzoIw3nMz-mDLmiCJ4kaAi1eEALw_wcB&ohost=www.google.com&cid=CAESVeD2Qpa4KpxVUV4qBTy_Kw3FPfEPU4YHedQY-gdNEMLSaIagtFn_hiZEgg56mWT7iI7lQtl3Uiib1zIIBPNROkcVfkWk1Oyb90y1PT8ZqOd3iBfD5RQ&sig=AOD64_1PNv_F99OpBRHvr5Z6cKTmhHTLdQ&ctype=5&q=&nis=4&ved=2ahUKEwjVmKa2mNSJAxUY1jgGHRCXDQwQ9aACKAB6BAgFECc&adurl=)
PS....I would only use a Registered Named Heat Transfer Paste, and stay away for e-bay [Asian no name :-X goop]
-
Derek,
Thank you for a kind and professional comment on heat transfer of the water -cooling coils I made.
Yes, indeed , what you have mentioned is surely true and reasonable for an effective cooling of the motor cans, as well as
is ideal and better to do. However, as you know a brass (tube) itself is also so good a material to conduct the heat and I made
the coils to get them to touch as much surface of the motor cans as possible to contact the water inside the coil tubes.
Even this level of craftmanship will I suppose do a good job from my experience of brushed motor boats in the past.
This style of cooling is not the best, but necessary and sufficient style for this PT-109(JP).
I have learned a new knowledge that you suggested to use thermally conductive paste.
I will keep it in mind :-)) :-)) .!!!
The pick of steel tank (98 pounds) is equipped with a cooling water coils and a radiator to run in the summer.
All the drive system is fully covered with steel which becomes toooo hot in mid-summer. Only forced water cooling system
could save this tank in summer run. Just an appendix!!!! :-)) :-)) :-)) :embarrassed: {-)
Thanks Derek.
-
Perhaps they are too small but did you not try to get inrunners with a waterjacket for cooling. I generally don't use inrunners as my main use for electrics is aircraft but I do have 2 fast electric models where the motors have waterjackets for cooling.
Jim
-
Hi JimG,
Thank you for always constructive comment.!! :embarrassed:
I selected my inrunner motors basedon the some factors.
They are the size of diameter, price, comparatively better heat dissipation and sufficient KV value for this size of boat.
Moreover, there is no need for me to choose so powerful brushless motors for my 29.5 " light weight pla-model boat.
Even my motor could produce about 0.55 Hp each and two are equipped in my boat.
The pics below are marine-application brushless motors with water-jackets in my fleet. But too powerful and no adequate(smaller) ones could be found in the market when studying what to choose. {:-{
Above all, inexpensive for the quality is main reason this time for this experimental pla-model boat.!! %% {-) :D
-
Well then, here is a post for today.
I could reach a final setup with the brushless motor basis at last. !!!! :-)) :-)) :-))
Chinese-made brushless motors and ESCs as well as lipo in the US-made hull are largely expected to run powerfully by which the PT-109(JP) is able to sail like a modernised MTB with the jet propulsion...!!?? {-) %% O0 :-))
-
I wonder if steering might be an issue?
My PT boats are light and overpowered with a brushless (which is a good idea because with not much load they run cool and don't have any cooling issues)
However, the hull form will cant almost 90 deg if you do a sharp turn at speed. I cut back the rudder to minimise this, and suffered some low speed lack of steering authority. I'm not sure how a jet boat will behave over a wide speed range - the hull is not a racing flattie....
-
Hi dodgy geezer,
I'm so glad to have your kind comment and information of your PT boats.
Steering angle of nozzles of my PT-109(JP) does not look sufficient at a glance, however a boat is inclined to turn easily and
sharply at speed. Moreover,I haven't normally tried to turn sharply in order to avoid an upset so far.
See the video below for reference.
In addition to the above, I set a pair of bilge keels to reduce risky cant, which I have felt is largely effective as in the video below.
Anyhow, everything will be made clear in the maiden voyage to be held within the month...
I wonder she could really run well enough as my first jet driven MTB....??? {-) {-) {-) :embarrassed: :embarrassed: :embarrassed: :o :o :o {:-{ {:-{ {:-{
Lindberg 1/32 PT109 sailing test resulted in success in the third trial run. (https://www.youtube.com/watch?v=R7QKh8ptwj0)
-
Jet thrusting power test was done in the bathtub for close to 10 minutes in 3 times of different RPMs of the brushless motors.
I have gotten the motors to run 2/3 throttle in the final test starting from the idling basis.
The most anxious was the water ingress and motor cooling in this bathtub test. But successfully done about the points. O0 :-))
With this test I have felt that this PT-109(JP) could be worth actual sailing test on our local lake. :-))
Without the actual test run on the lake, I can do nothing any more to know if the boat could really run like a water jetted MTB
able to run on the lake. O0 To tell the truth, I am not confident that she could perform a nice job like MTB because of no experience to build or to modify at all so far..... I wonder how she should behave in the lake test....?? Bow up? speed?
nice and stable turn? overheat by "continuous" high speed run..?? mechanical trouble leading to a sudden stop far away
from me?? <:( <:( <:( No experience and few knowledge do do do get me fear the test on the lake.... O0 O0 O0
Pics; Can you identify the difference of water force of drain between the two pics? (No2 and No4) ?
Pic No1 shows 2/3 throttle. More power? Oh no, I was scared with the jetted force even with this level at this distance. O0 {-)
-
Primarily bath test was done successfully at the 2/3 throttle with which I was satisfied to some extent. O0
Well then, do I go to the painting work as I am eager for an initial trial run within this month to get her commissioned within the year since this is an autumn project..?? :embarrassed: {-) And it will be colder for the actual test... O0
For the above reason, I painted the hull and deck in a hurry.
-
Fundamental painting was done all over the boat and she had better be weathered a bit.!! O0 :embarrassed:
Since she just does look like so-called a "pla-model" unless weathered.!!!??? {-) {-) O0 O0 :D :D :o :o
-
Ready for the maiden voyage :-)) I will keep fingers crossed that all will go well, Kiyo! O0
-
Arno, a great thanks for your encouragement for me.!!!! :-)) :-)) :-))
Well then, shall I try to boost it ahead with this jetted MTB on the lake in the near future if it's fine weather.!! :embarrassed: O0
Like our latest H3 rocket succeeded in launching the other day totalling to 3 continuous success. %%
-
I installed a foldable wave deflector over the jet nozzles for an easy service of nozzles as well as deflection of the wave and a
scale like good appearance. O0 {-) :-)) As this is an experimental jet MTB that I have challenged to build and sail her on the lake. :embarrassed:
-
And I weathered the boat briefly and roughly like these. Coming to a final configuration gradually..!! :-))
-
She is no more USN PT-109 but IJN PT-109JP by the national flag and the navy ensign as well as twin jet thrusters. O0 O0 {-) {-) :-)) :-))
-
At last, I happened to find a nice weather yesterday for testing my PT-109JP.
At first, I checked the balance and confirmed it OK for an initial trial run after checking radio wave range test at the distance
of 82ft.
And I got the boat afloat and set the balance as seen below. O0
A model ship does look fine when floated on the realistic water under the nature once completed, not in the bathtub, doesn't it.?? O0 :-)) %%
Pic No1: The sunlight was reflected tenderly along the starboard via water surface in the deep autumn of Japan..... :-)) :-))
The water was fairly clear and clean typical of mid-autumn of Japan and suitable for RC boating as well.!!!! {-) {-) %% %%
-
Great pictures, Kiyo! Over here we have rain and snow at the moment….
How did she perform on the water? Was the thrust of the jet drives ok?
-
Good morning, Arno and good cold evening here in Tokyo with a slight rain fall.
Thank you for your comment and interest in the sailing performance.!!
At the same time, I am awfully sorry if I have you provoked due to no reference to the important sailing performance.
I did not dare to refer to the point as I had thought it would be done in the next post.... {-) O0 <:( :o
But you showed an interest in the above comment, I will post so tiny pieces of pics below prior to the main body of sailing pics
to be posted tomorrow. :embarrassed: %% <:( Please excuse me for my provoking thought. {-) {-) {-)
1, Safely started !!
2, Safely returned !!
-
Many thanks for sharing the photos, Kiyo, it all looks promising! I did not want to force you, it is only that I am very interested as my build has jet drives as well which so far have not performed on our club pond….
At the moment I am installing the trim tabs and reversing buckets. When that has been done, I will post some photos on the forum in Kim‘s thread. I am still waiting for the Super X glue from Tokyo, which is now at the customs office in Amsterdam….
-
Hullo Kiyo........I have followed this thread from day 1, & progressively wondered about the Jet Drive water exit axis...[relatively to the waterline]
I have Zero knowledge of these types of propolution apart from viewing a few U-tube shows
This function I don't understand :embarrassed: is semi-submersed jet water output, as compared to alternate submerged jet water output
The attached image is the RLNI lifeboat build here, but with submerged jet water outputs........
I keep on questioning the component of the jet water output :o above water....could it be wasted energy?
Derek
-
I'd like to respond to your kind comments in order of posting. O0
Arno,
I'm awfully sorry to have kept you waiting so long on the report of my first trial run on the lake.
I declare proudly hereby that the world's first PT-109 1/32 propelled by the water jet thrusters has been born successfully
at any rate.!!!!! O0 O0 :-)) :-)) {-) {-) {-) %% %% %% This is merely an experimental prototype of MTB built and modified from just a pla-model kit. My PT-109 JP does not have such nice reverse buckets as your refined ones.. <:( <:(
Needless to say, additional improvement and adjustment are surely required to get her to sail for more refined running. O0
And this trial is just the starting point for a better jet-driven MTB PT-109 as to need more months to go.!! O0 ;D :embarrassed:
Arno, the video will be, of course, exhibited here tomorrow. A motion picture tells truly, honestly and vividly all how it performed. :-))
Seeing is believing.!!! %%
-
Hi Derek,
Thank you for a nice comment this time as well.
All what you mentioned was truly to the point and a good question, since even I have been wondering how I should set the
nozzles position against water line throughout this experimental build.
I do not have any experience nor instruction manuals to which I am able to refer like the holy bible in life except not so many
information in the internet.
To tell the truth, I have been questioning by myself how I should set the angle of thrust line against the water line and the he ight of the nozzles along the transom.
The former one was sooo difficut to cope with by myself and decided to set it along the bottom of hull. {-) O0
The latter is what you mentioned and I have seen a certain you-tube(a Japanese posted) in which the Japanese denied to set
the nozzles fully in the water as ineffective than fully over the water through his experiment in the you-tube..... O0
Therefore, I simply decided to set the nozzles at semi-submerged line as seen in my pics based on partly because of the Japanese experience.
Anyhow, now I am planning to try various ideas to search for what will be the best for a better sailing performance with these
jet drive units and brushless motors, which is one of this experimental projects. O0 O0
-
Hullo Kyio.....just a few points..
1] I fully accept that the MTP- 109 vessel is not intended to be a speed boat of a totally different class and configuration
2] I believe the original MTP Class of vessel when @ speed displayed a stern down in the water with a sizable powered wake fantail trailing the speeding vessel, and all the time whilst raising the bow up & so achieve the plane on the water
I think you have achieved all of these points in this, your latest build :-))
There is another point often commented......." a fast designed boat going slow does not show any real interest :-X "....whereas an alternate designed vessel going slowly but whilst displaying a great volume of spray from the stern will always of interest" O0
OK?
Derek
-
Hi Derek,
Yes, indeed.!! I quite agree to what you stated in the last paragraph.
So far as this is originally a RC scale MTB PT-109 1/32 which MTB is not a racer but a fast sailing(sailable?)craft, she has to run
moderately fast, not like a turbine-jet runner. {-) :D
My initial aim to build this water-jet boat is partly because I was bored with a conventional type of screw propeller for this PT-109
as I had been enjoying a nice and sufficient speed by my second PT-109 already, which video was frequently shown here. O0
This boat could afford to gain more top speed by some ideas I have in mind and I intend to apply them seriously for her within
the year, if possible. :embarrassed:
I like such a RC model just as T-type Ford 1914 to be able to run at speed over 60MPH.!! {-) {-) %%
Pics; Trailing wake is quite different each other naturally.
-
Yes, the MTB certainly shows the fantail wake over the conventional propeller drive.........looks fast at any speed O0
I equate a similar observance or comparison......a conventional propeller driven Ferry vessel at 3 MPH, to a Ferry of similar size, but paddle wheel driven ....at the same speed 3MPH thrashing the water about <*< as she moves bye :P
Derek
-
Derek,
I found an interesting you-tube of a missile patrol boat driven by tri-jet drives of Japan maritime self -defence force (so -called Japan Navy nowadays). As far as I can observe it, her nozzles of three jet drives seem semi-submerged....in this case...???
Bing 動画 (https://www.bing.com/videos/riverview/relatedvideo?q=%E3%82%A6%E3%82%A9%E3%83%BC%E3%82%BF%E3%83%BC-%E3%82%B8%E3%82%A7%E3%83%83%E3%83%88&mid=FA90E8877963B548B8C4FA90E8877963B548B8C4&ajaxhist=0)
-
A couple of observations about the nozzle position. I have the Graupner Pilot boat with 2 waterjets and the nozzles are positioned above the chine height at the stern so would be semi-submerges when stationary. This position works well at all speeds.While the Shannon has the nozzles below the waterline when stationary it does have a planing hull which would be expected to lift at higher speeds bringing the nozzles above the water level, I would expect the transom to be above the water flow so the nozzles will be fully exposed, the trim tabs should help lift the stern clear. Having them submerged at low speeds may add a bit of extra thrust when the jet flow is pushing against the water more like a propeller but the main thrust from a jet is by throwing a mass of water behind the boat and using Newtons laws to propel it forward, no need for the output to be submerged.
Jim
-
I cannot tell how the thrust of the Shannon boat works. At low speed the nozzles definitely are submerged, but at high speed they might well be semi submerged. I have attached some photos of the Open Day at the Dungeness lifeboat station in 2017, happy days….
-
at high speed…
-
JimG,
Thank you for always nice comments.
Your information mentioned above from your experience could be soooo useful for me this time too as I am quite a beginner
in this water-jet drive system. And I could deepen so informative and scientific knowledge concerning jet drive characteristics. :-)) :-)) :-))
What you mentioned did meet what a certain Japanese in a you-tube had confirmed that nozzle fully in the water did not contribute less to thrust the boat ahead than fully over the water. As you mentioned, I just once imagined that sizeable and fast volume of jet flow over the water might be something like a key to push a boat ahead fast like a rocket......But I was not completely confident about that in those days. {:-{
Therefore, I set the nozzles of my MTB at semi-submerged conditions provisionally as seen in a missile patrol boat in a you-tube posted above. See the pic stationary on the water and the other sailing fast when the nozzles were over/on the water
subsequently....?? :D :embarrassed: {-)
Anyhow, thank you for sharing your precious information on the jet drive mechanism with us. :-)) :-)) :-)) %% %% %%
-
Arno,
Thank you for some nice shots of real Shannon boat sailing so powerfully with sizable splash.!!
I suppose your Shannon will do the same actually on the water as the real one with its museum quality appearance. :-))
When are you supposed to make a trial run after applying Super-X Black.?
You had better keep the model left over 24h minimum for a secure cure.
I am waiting for your Shannon to make a wonderful trial run in the very near future in Kim's thread.? :-)) :-))
-
I'm so glad and happy to be able to post this video on here of the first trial run of this boat started to build three months ago.
Whether or not the content would be satisfactory is entirely dependent upon you yourself, but it's a bit significant for me
to be able to post the video of the experimental project to build a jet-driven MTB from a Lindberg Pla-model kit regardless of the content. O0 {-) :-)) :-)) This is merely a prototype of a better jet-driven MTB to be expected to perform much much better on the water. :-))
Please watch it in full screen of PC for better and vivid appreciation.!! :-))
The video will surely tell all that I want to comment more eloquently than my poor description in three-minute watching. :-)) :-))
Bing 動画 (https://www.bing.com/videos/riverview/relatedvideo?q=Lindberg+PT-109+1%2f32+water-jet+propelled&mid=DB7D8603E7665D157AC0DB7D8603E7665D157AC0&FORM=VIRE)
-
I have watched the video and enjoyed it, Kiyo, although I was not able to understand the comments of your wife as I do not speak Japanese {-) It all looks ok for me concerning thrust and maneuverability.
Over here we have ice and snow at the moment and I cannot do the paint job of the deck. So my maiden voyage will not be possible before next spring.
-
Thank you for a warm comment, Arno.!! I'm so glad to read it.!!
My wife said," May this boat succeed in the first trial run!!" in the former shout and "3 minutes have passed" in the
latter. {-) {-) She played a role of both a camera-woman and a time keeper for this test sailing as I forgot to carry a kitchen timer around my neck.
I've often heard from a friend of mine working for a trading company that Germany is generally cold across the country and it's understandable if I may see an atlas of Europe. That's why Christmas in snow of Germany is so famous and my wife has
made me nervous to appeal her strong wish to see a Christmas scenes at night in snow of the country. {-) {-) {-)
The notorious is the very low Yen value that has been a worst reason to disturb the trip to overseas travels among the Japanese. <:( <:( <:( {-) {-) {-)
-
Your wife does a very good job as camera-woman :-))
I have attached a photo of how it looks like over here today. Not much snow, but enough to get an impression of winter.
The weak Yen is convenient for us though: my daughter is planning a visit to Japan for next year (again).
-
Arno,
A great thanks for the photo you sent me and I have shared it with my wife right away. O0
She said it looked something fantastical since it was quite different from our normal circumstances at all, while it may be
nothing but normal and daily scenes for you, though.... O0 :D
Anyhow the scenes covered with white snow may generate something fantastical or mysterious partly because of strange environments of your country against Japan...
Thank you again for the photo.!! :-))
PS;
It is too long for you and me to wait and see Shannon sail on the water until next spring while she is nearly about to launch at the moment. <:( <:(
-
A rescue operation done in the second trial run.!!!!!!!!!!! <:( <:( <:( <:( <:( <:( :(( :(( :(( :(( :(( :o :o :o :o :o
Everything did not always go well in this world, didn't it.!?...........Our latest H3 rocket failed in the first launch followed by
3 successful continuous launches thereafter.... :-))
A flock of waterfowl was watching me save the boat anxiously, interestingly and curiously as seen in Pic1...
I wonder they would understand my feeling of the time or despising me for the failure..??? {-) {-) {-) {-) {-) {-)
My PT-109JP was sailing very well in the first 2 minutes in the second trial run and suddenly stopped about 40 m(131ft) off the
shore just after Port steering.!!!!!!! >:-o >:-o <:( <:(
Right motor was judged to have had a trouble after examining the cause......Left one quite well......
-
Oh Kiyo, what a pity! I hope you can find the reason for the failure soon. Did you take the inflatable boat with you in your car? At least you had the possibility to rescue the model safe and sound…
P.S.: My Super X glue has arrived yesterday, no customs fees and no import taxes :D I will give it a try today, then wait until it has fully cured, followed by a longer bath tub test….
-
I found the cause of motor trouble unlucky due to the cheap motor which are often unstable in its quality...
Or insufficient cooling of motor on this right side since I felt too hot right after first trial run while cool on the left motor.! O0
I will be able to re-start the trial/improvement run from this December after having a replacement motor made in China again.
I normally make it a practise to carry an inflatable rubber boat whenever I sail a brand-new boat at its early stage or I am
not confident of a boat from its past experience.....
I have ever lost a RTR tugboat here several years before, that was drifting away for 2km(1.25 miles) after sudden stop... <:(
I chased it from the shore in the mid-summer as far as chained buoies like a rope (I do not how to express correctly ) where it was forced to stop and seemed to sink as I could not see it any more..... <:( O0 {-) Only one victim here... {:-{ :D
Quality of the Super-X is really excellent as this is Japanese brand of Cemedine brand.!! Very famous and traditional brand of adhesive and its relating products here in Japan. O0 O0
I will be so happy if I could enjoy a nice Christmas cruise before Christmas with a Santa Claus as in the pic..!! %% {-)
-
Arno,
I once watched this interesting, unique and useful you-tube for my PT-109 JP setting concerning the position of nozzle along the
transom.
He concluded from his experiment that nozzle set over the water came to be much much effective to thrust the boat than fully in the water.
This conclusion seems to match what JimG previously mentioned.!!! O0
Bing 動画 (https://www.bing.com/videos/riverview/relatedvideo?q=%E3%82%B8%E3%82%A7%E3%83%83%E3%83%88%E3%83%9C%E3%83%BC%E3%83%88%E3%82%92%E3%81%A4%E3%81%8F%E3%82%8B&view=riverview&mid=F58850AA5024259DCF90F58850AA5024259DCF90&ajaxhist=0)
-
Kiyo, I think this is no contradiction. When the Shannon boat comes to planing, the nozzles might well be above the waterline and so do yours. The Shannon ones are submerged only at low speed.
The guy in the video does not get to planing his state-of-the-art hull🤣
-
Arno,
This is just a question on your Shannon.
Does she have trim tabs already.?
Can I see them if you don't mind showing here..? If possible, I also intend to install provisionally in my experimental PT-109JP
to know how effective tabs of my style will be in my boat. O0 :D
-
Hi Kiyo,
I have attached some photos of my trim tabs. I have installed them yesterday :-) They are workable as I have soldered a steel wire into the cylinder which is attached to the tabs. The tabs are made of brass sheets, cut to size and then soft-soldered together. I have used brass tubes for the cylinders.
You will also notice the fixing of the bellows, having used Super X glue. I will do another bath test when this has fully cured and then attach the deck if the test will be successful (i.e. the hull will be dry inside after the test). The trim tabs can be adjusted using the slider controls of my Futaba transmitter. It worked fine during the dry test yesterday.
-
Wow!! Arno, amazing!!!! Your Shannon with an extremely refined construction of jet drive with reverse buckets.!!
And it's so large a boat enough to install also nice and adjustable trimtabs by your radio stick work that is really like a real system including the shapes.!! :-)) :-)) :-))
Moreover, these jet-drives look to adopt a pair of fully advanced thrust vectoring nozzles, don't they?? This is also amazing.!
So well crafted and constructed, Arno.!!!!! :-)) :-))
I could generally understand how your trimtabs were made.
Thanks ,Arno!
-
While waiting for new motors of replacement to arrive at, I painted 6 crews and got them be at quarters as seen below.
The rest two are still taking a rest for future service. :embarrassed: %%
I think they will surely experience comfortable speed by jet power actually aboard the boat. :-))
How I envy them.!!! {-) %%
But it will be soo cold in coming December.... Me too!!!! {-) {-) {-)
-
I'm currently so happy to have myself indulged in building so unique an MTB PT-109 jet propelled based upon my own ideas and design using Lindberg pla-model kit for an autumn project. O0
Anyhow, a jet propelled boat is itself very new to me and therefore I have little knowledge about its behavior how it performs
together with the boat on the water. In such a background, I intend to try some experimental tests furthermore to make my PT-109Jp much better until I will abandon my improvement efforts.
I added a kind of trimtabs to get my-desired balance in sailing at speed. These tabs were this time just set as the starting point.
This boat is merely experimental so that I wish to try some tests having the interest and collecting knowledge. O0
-
Though I am a novice to jet drive propulsion just as you, Kiyo, I am quite sure that it will bring an improvement. What you might consider as well are those fins underneath the hull which the Shannon boat has. I think they improve the running straight ability.
I hope the next test will end without the need of using your inflatable boat %) :-)) :-))
-
Arno,
The inflatable boat is perfectly prepared to carry with me currently for emergency.... {-) {-)
As I had a very terrible experience to take a looog time to inflate it just after the sudden stop of PT-109 on the water during which the 109 had been drifting away from the initial place of stop on the water already..... <:( <:( <:( {:-{ {:-{ {:-{ :o :o
I haven't used the inflatable boat for many years up to the day since last I had used....I forgot how to inflate it correctly under
emergent condition.... {-) Normally ten minutes to inflate it but might be close to 20 minutes in my feeling..?? <:( :-X :o
I am expecting how she may behave in the next trial run with the trimtabs and other countermeasures taken into the boat based on the first trial run. O0 O0
This time I have two crews set to let them check how cooling water is drained during sailing since I am completely unable to see it due to the wave beside the freeboard as seen in the pic. {-) {-) {-) :embarrassed: ;) ;)
-
A new replacement motor arrived and I set it in place after setting a clamp to tighten the cooling coil for better contact
with the motor to get a better heat exchange. O0
The new motor worked very well in the bathtub test for two times of 5-minute run and ready for next trial run on the water.
The test is supposed to aim at confirming if the trouble of sudden stop on the water in the last test should never happen again and trimtabs also might produce something effective for a better sailing behavior.
Needless to say, speed performance may well be improved by some measures I had applied.
According to the latest weather forecast, it will be fine fundamentally throughout next week. :-)) :-))
Everything is up to my boat itself whether or not it will be successful...??? {-) {-) {-) O0 O0 O0 {:-{ {:-{ {:-{ {:-{ {:-{ {:-{ {:-{
I will be very happy if I could post nice shots of sailing here of the run..... {:-{ {:-{ O0 %%
I wonder if she is sufficiently tolerable against fast continuous speed run by powerful brushless motors judging from the last experience...???? O0 :D Many screws loosened?...ESC burned out?...motors also blown off?...motor mount cracked?..
Or Should I treat her like a tame cat rather than a wildcat on the water..??? %% O0
-
Hi dear, just pics for today.!
It was really nice day here in Tokyo for sunbathing in the sun given by a slightly hot temperature of 18 degrees C(64.4 degrees F)
, no cloud in the sky and no wind over the lake as seen in the pics. O0 :-))
I manned my PT109JP and set it to take the sun for a while from stem to stern as in the pics. :-)) :-)) :-))
Take a look at our naval ensign of the rising sun which really matches the sunny day, doesn't it. ? {-) %% :-)) Wow!
-
Wow Kiyo, lovely photos! And yes, the ensign matches perfectly :-)) It all looks very promising for the next test run.
-
Arno,
Thank you always for a friendly comment.
A jet-driven boat could be more promising as one of the drive systems for RC vessels, at least for me.!! O0 O0 :-)) :-))
What a happy day, a happy place, a happy boating, a happy hobby, a wonderful world ♩～♪～ under the blue sky and warm, calm weather.!! :-)) :-)) ok2 ok2 ok2 %% %%
-
Well, it's a highlight of the second trial run to report for today.
Yes, sailing scenes of the 109JP in standstill images.... :-X {-) However they are rather impressive, dynamic and appealing
often than motion pics like video. O0 O0
Here we go!
Pic No4 is at full throttle scene. :-)) :-)) :-))
Just some remarks;
a) My own style of trimtabs set this time were functioned to some extent as to reduce ugly and unrealistic rooster tail like wake.!
Due to the tabs, tail wake could be kept lower and sharper as she got faster than in previous trial run. :-))
On the contrary, Stb motor stopped again at terminal stage of sailing at speed while Port motor was quite OK enough to drive her home powerfully at shore. O0 :embarrassed: :-)) <:( {:-{
b) The tabs also contributed to refrain from excessive bow-up tendency at high speed. O0 :-))
c) The waves beside the both sides were comparatively well formed clearly and sharply by added bilge keels as in my PT-109
screw propeller boat previously completed.
Fortunately or unfortunately, inflatable boat could not have any chance to go afloat on the water though fully swelled put beside me... {-) {-) {-) :embarrassed: :D
-
Kiyo, I hope you can find out soon the cause for the motor failures! Apart from that the photos show that she sails nicely on the water. What revs does your setup achieve at full throttle? My Kehrer jets should not have more than 20,000 revs, which I do achieve using 1,600 KV motors running at 3S lipo batteries.
I had another setback as well as I still have some water ingress. I found out that it must be where the jet drives protrude the transom. I had used Gorilla glue for the joints as this expands into the material. I now have ordered some more Super X from Japan and will apply that also in those places. Did you do that as well with your drives? The Super X does a fine job so far around the bellows and all the other protruding places, for example the fixings of the trim tabs and the reversing buckets.
I am sure both of us will be getting there slowly….
-
Arno,
I have understood your embarrassment on setting the jet drive system quite well since I already had nearly the same experience
and took much trial and error for solving such troubles, though I did not refer to these points so far in detail. O0 :embarrassed: {:-{ <:(
1) As for the motor revolution; I have not measured it. I simply am using a 2S lipo 5000mAh battery with 4000KV brushless
motor. Unlike your large? motor, mine is so small that inevitably KV value seems a bit higher...although this motor is also
applicable for 3S lipo by its specification, if necessary. BUT I haven't felt it necessary to use 3s lipo at all. See the pics posted above. It is 50000RPM max with 3S lipo by its specification, namely 3S x 4000KV=about 50000RPM... O0 {-)
Anyhow, powerful enough with 2S lipo...see pic below.
2)As for water ingress; I was also terribly embarrassed by this ingress frequently in early stage of bathtub tests made many times. <:( >:-o
In order to prevent the water from coming into the hull, I used super-X finally all around the base of pump units and all the protruding places beyond the transom sufficiently after all by which no drops could be found in both bathtub and on the-water-test.
I addition, a few drops of ingress was confirmed coming through the stb impeller shaft against which super-X and a good amount of grease as well as double O-ring did a very good job to stop the water ingress. !!! :-)) :-))
Double Oring can be seen in Pic4/5 clearly.
In the early stage of installing the pump jet units, I thought the gaskets would work sufficiently to stop the water ingress in vain.....insufficient and Super-X solved the embarrassment completely..!! :-)) :-))
-
Thanks for the photos and information, Kiyo. I will do the same around the jet pipes and that will hopefully solve the problem. I now am waiting for delivery of the Super X sealant.
The Kehrer jets are allowed only about 20,000 rpm because of the bearings. Your setup might be too much revs concerning the shafts and bearings?! I have no idea why your one motor has this problem and hope you can solve that soon.
-
Arno,
I'm sorry to have you misunderstood the set-up of the radio gears.
I just mentioned the capability/specification of the motor referring to 3S lipo and actual set up is by 2S lipo that is quite Ok
as in the pic No1 in the above post. Theoretically my motor could produce around 33000RPM at no load, but actual RPM will
possibly be far less than or around 20000RPM at best due to many factors... O0 %%
Moreover, I could only believe in partial parts of the specifications of the motor made in China from my several bitter experiences in the past. O0 :D {-) %) I suppose the motor failure will be solved shortly in the month in the third trial. :embarrassed:
I am intending to improve a bit sailing attitude at speed for more scale realism. :embarrassed:
-
OK, that all sounds reasonable to me, Kiyo :-)) :-)) :-))
-
And this is the video of the second trial run to have come successfully to end with a partial failure.... <:( {:-{ {-)
I already think myself to have found the cause of the trouble of the motor, though direct cause may have nothing to do with
the motor which I'm not sure...
The third test will exhibit if my supposition should hit the case shortly in the month. O0 O0 {-)
https://youtu.be/IFC2I6fBDRA (https://youtu.be/IFC2I6fBDRA)
-
Kiyo.......she accelerates in a most scale-like motion :-)) ......[she is not a speed boat]
The sound in the video opens up some questions in-relation to a drive alignment?, or shaft-to-bearing tolerance within the actual impeller shaft within the pump itself
In the timeline.......26 seconds >>>>>.40 seconds as harmonic resonance, then ...... to 50 seconds an alternate resonance ...there are other resonance sounds, however these first two [edit] for a start O0
Do you hear the same? :o
Derek
-
Derek,
You hit again interesting point of sound change about which I have been annoyed to some extent....
To tell the truth, right motor is possible the key to solve these subjects/problems.
while right motor is so smooth in revolution by fingers as well as left one. O0
The set-up of the pump units are I'm sure well securely done and alignment between motors and impeller shafts also
seem OK.
One point I feel anxious about is the design of setting a motor to its motor mount of the pump unit which seem a bit
unstable and unbalanced for a very high speed rev. brushless. To make the matter worse, the material of the pump is plastics which may be apt to irregularly vibrate at rather low rev. not at high rev,. O0 {:-{
But left motor has kept on working since the set-up.
At any rate, vibration and resonance are normally clear at low rev,. and would disappear at over half throttle for my ears. :embarrassed: (for my right ear with a hearing aid) {-) {-) {-) {-)
Another point to cause such resonance or vibration I suppose may come from difference of calibration of ESC between the two.
I am trying to adjust the right ESC properly to be arrived soon according to the instruction manuals. :-))
At any rate I could enjoy this pla- model jet boat to make her better for a month or so to come. {-) {-) {-) {-) {-) Wow.!
-
By the way, I tested the jet capability of my jet pump unit actually on the lake (not on the bathtub water) to confirm how much powerful it would show me. Since I have imagined already it would surely drive me to a terrible result to get me drenched to the skin right after starting the test in the bath room. {-) {-) {-) Oh,my goodness! :-X :-X <:(
Attention even to the drain of the cooling water in the form of long and sometimes a bit linear flow not arch.. :D :o
What should I represent this wake other than "this is really jet"!!?? {-) {-)
Arno's jet of his Shannon is possibly and surely way violent than mine like rocket (not jet) like power by large brushless motors.... :-)) :-)) :-)) %% %% %%
-
When I was watching the video carefully of my 109JP for analyzing her behavior on the water, I happened to come across unique
scenes that one or two waterfowls was observing my boat seriously to pass in front of them. Followed by consequent anger..? :o
Is it only me who to understand the waterfowl in that way.!!? {-) O0 :embarrassed: ;)
Apart from your understanding the scenes, it may be true that the scenes may reflect a good harmony between the boat(artificial) and the waterfowl (Nature), isn't it.? :embarrassed: {-) %%
In this sense, RC boating on the water may produce such "a byproduct" other than boating itself....??? O0 ok2 :-))
And I may be so happy to be able to enjoy such a byproduct at home and Nature beside the lake ... :-)) {-) Wow!
-
Hi mates,
It was a very fine day yesterday with the air temperature of 14degrees C and around 2m/s of wind speed, slightly windy and choppy on our local boating lake as in the pics below. A bit severe for a trial run for my small pla-model boat, but this is a MTB.. %% %%
There was no reason why I did not go to the site for the weather conditions at all for the third trial day. O0 O0 :D
Since I just applied some countermeasures to improve my 109JP as to meet my image of sailing performance as a model MTB. :-))
Before actual sailing of the small boat for the lake, I checked the balance as I had reset the battery location and a small ballast as well as trimtab angle to get it slightly negative side for much better planning attitude with a higher speed capability.
The choppy lake was not cooperative with the test a bit drenching all the crews to the skin. :o :D O0 {:-{ %%
Compare the size of wave with the boat swinging like a piece of leaf floating on the water..!!?? {-) {-) {-)
Therefore, I previously inflated a rescue rubber boat for a quick response against sudden stop of 109JP due to an accident.
-
Photo no. 7 is just beautiful, Kiyo! :-)) :-)) :-))
-
Thank you so much, Arno.!
Yes, that looks good to my eyes, too. :-)) :embarrassed:
-
Hi RC sailors,
I'm so glad to be able to post such nice shots as I think they are from the trial run carried out the other day as seen below. O0
Trial run this time has reached the third day and I think the result is generally OK since a remarkable improvement has been
confirmed in both top speed and sailing behavior by some countermeasures taken after previous 2day trial runs. :-))
Especially, the new negative trimtab angle seems to have largely contributed to lift the stern up by which top speed might have been increased together with a better planning attitude. O0 :-))
Above all, sudden stop on the water of which I was so much afraid never took place even under the choppy water conditions.!! :-)) :-)) :-)) Sailing attitude looked as if she were sliding smoothly on the water to me thanks to the new angle of trimtabs.
Strange as it may sound to you or not, I this time have applied car wax over the semi-gloss colored hull bottom for both good speed and easy maintenance.
Nevertheless, further improvement still may continue.. Next trial is scheduled to carry out around Christmas day. :-)) :embarrassed:
Enjoy the pics of small pla-model MTB on a bit rough surface of lake, as well as low and long jet flow generated from the twin nozzles over the water by the new trimtab angle for one reason . :-))
-
I am happy that you achieved even more improvement Kiyo, well done :-)) :-)) :-))
Please send us a photo of the trim tabs, so that we can see the angle. It will be interesting for me as well, as so far mine are set level with the hull.
Do you have any idea what has caused the blown up motors before?
-
Arno,
Here are the photos concerned with my so primitive the trimtabs set this time as slightly negative side (down side from the level with hull bottom). My PT109JP is too small to install hi-level of wireless power-driven trimtabs like yours. <:( :((
So, my style of adjusting the angle of the tabs are simply dependent upon wedges to be driven between the hull and tabs which thickness is very ""angle adjuster". {-) See the detail in the picNo.2/3/4 below.
A wedge is able to move up and down a bit until optimum angle is found. If not done, another new wedge will do instead...Soo primitive!!!! {-) %%
Pic1; Trimtabs set like this for the third day trial.
Pic2/3; The angle of the tabs set slightly negative for this third day trial run.
Pic4; You may confirm so simple a wedge.
Pic5; Very first trial run with no tabs by which bow was too high for my eyes. O0 The stern decks seems as low as the surface. <:(
Pic6;The second day trial with tabs set level with hull bottom didn't show an apparent difference from the first trial in the bow attitude. {:-{
Pic7;The slightly lowered tabs might possibly have done a good job to get the stern a bit high by which the jet flow came up
a bit more over the water surface and generated more volume of jet mass contributed possibly to speed-up. O0 :-))
See pic1 of previous post that shows mass of jet coming out powerfully on the water surface. O0
As for the motor problem, I replaced the motor with a new one together with new ESC by which no problem arose in the two trial runs on the day and the motors were a bit hot right after each run. :-))
This will be another subject for next trial. :embarrassed:
-
And this is the video of the third day trial run that tells everything concerned with the sailing behaviour.
No need to say any more with lots of description.... O0 It's entirely up to you how you understand the contents.
https://youtu.be/u0b118KNsbs
-
That looks like a really good setup now, Kiyo!
My trim tabs will be able to reach a similar level so I am confident that my model will plane nicely as well. And I always use cae wax as well after my paint job. I think it is a good protection for the paint.
I am happy that your conversion turned out nicely. The video is impressive. What does the woman’s voice in the background tell? Nothing about the model I suppose?! %% {-) :-)) :-)) :-))
-
Thank you for always your complimentary and friendly comment. %% O0 :-))
My wife is playing a multi-role woman at the boating site like a timekeeper, a camera woman and a director to get better video scenes.. {-) {-) {-)
I am so much interested in your gorgeous Shannon to sail magnificently and powerfully, but it is scheduled in next spring?!..due to winter season... <:( <:( <:( But it may be you yourself who are much more impatient of waiting for the next spring to come rather than I am, isn't it ....!!!!????? O0 O0 O0 O0 O0
Arno, have you checked the moor cooling sufficiently actually as to use the boat in the bathtub for a few minutes at a certain rev,.already ? My boat is not necessarily complete yet still now at continuous top speed for 3 minutes or more..which is one of my next test themes to solve... As you know well, brushless motors in general are so powerful with excessively high RPM required to cool intensively especially during high speed run.... Take care of this point again for a successful test run. O0
I lost 2 cheap motors in this experimental prototype boat already.... <:( <:( <:(
-
I thought that in the timeline of the video after about 3 minutes it was not your wife but someone else making announcements via loudspeaker in the distance :D
I am waiting for more Super X which is in customs clearance in Amsterdam at the moment. I need to fix the problem with the water ingress first. Then I will fix the deck and paint it. That cannot take place at the moment due to the weather. I need to open the door of my workshop when painting as I use acrylic 2 component paint with solvent. It now would get too cold inside the room for a good painting result. So I need the patience to wait. I have been working for years on the build so do not want to spoil it on the finishing straight {-)
Cooling my motors with water will be impossible as I am using outrunners. So far I can only rely on the work of others having used Kehrer jet drives with that setup and did have no problems. The hull is quite big so there is quite an amount of air for cooling. Time will tell if it all works as planned. I agree that a bath tub test cannot simulate the real sail properly.
If I lived nearby you I would be able to finish everything soon, but with the ice and snow over here a need to be patient. Next project will be the SS Falcon kit from Ron Dean, something completely different.
-
I have understood concretely how far you should already have gone in the building process.
I think you may not have to be so impatient for the first trial run as you need more time to finish it completely. :-))
The announcement through the loudspeakers was warning the visitors of the park no to do dangerous things in the park. O0
How I envy you since you already have a next project, Arno !!! %%
while I'm too old to challenge such a large model. <:( <:(
If I should build such large models and leave them in storage, it will greatly and surely bother my wife about what she should do with them after left lonely by me..??!! %% %% %% %% %%
That's why I have been trying to play the RC models in these years already built in stock rather than building new and large models.
In addition, my house is narrow to keep many and large models.!! <:( <:( <:( <:( <:( %% %% %% %% %%
-
For a better and easy maintenance, I set a pair of nipples for blowing the water off left in the cooling tubes after finishing a day sailing. Unless doing that work, inside of the metallic tubes and ESC is apt to be rusted and/or stained with some sort of sediment
in a long time period by which a good flow of water will be largely disturbed, from my long experience.... {:-{ O0
Blowing the water off the line of cooling tubes is my routine job to do at home each time after cleaning the hull. O0
-
Let me show you just so short a video clip about my 109JP behaviour on the water, that was carried out as one of trial runs.
A water jet boat is found to be easily able to turn at minimum radius, not to say like Schneider propeller..!! {-) {-)
So much for today.!! O0 :-))
https://www.youtube.com/watch?v=2QA-svVBf9I
-
I enjoyed boating itself very much yesterday and took impressive pics about the wakes, splash and wave rather than the boat itself to which I would like you to mainly pay attention this time caused on a calm water surface. :-)) :-)) :-))
-
Today I would like you to see very unusual pics of so miserable result of 109Jp taken place the other day on the boating lake. <:( {:-{ :o :o
Yes, a lead wire was completely burned off on the water and the boat suddenly stopped generating smoke from the hull
for a while... O0 :embarrassed: {:-{ Another one was burned just out at only insulation covering of the wire... :embarrassed:
I used and operated the motor sufficiently within the specifications of Chinese manufacturer...
This was very first experience to have the motor blown off actually...a wire was broken off under the use of specifications.!!!!! <:(
On the other hand, I still use another Chinese-made motors which are OK currently. :-))
-
What a pity, Kiyo <:( So you had to use your inflatable boat again?! Did the motor draw too much current so that the diameter of the lead was insufficient? >>:-( <*<
My supply of Super X has arrived and I have applied it around the water jet drives. I will do another bath tub test after Christmas and hope there will be no water ingress anymore.
Keep up your good work, Kiyo. I know you must be upset after another setback O0 In the end both of us will succeed! Ultimately you might change the motor brand….
-
Yes, your imagination is perhaps true and too much current might have been drawn. O0
New brand of motors have showed a good impression so far in the intensive bathtub tests spending more time with severer conditions. KV4000 of old motors might have been too high with 2S lipo while new ones are 3200KV with 3S lipo under testing now repeatedly while increasing loads.
I also have been annoyed by the water ingress in the bathtub test reaching around 7 times or more as to add more Super-X
in each time... <:( {:-{
Thanks to a sudden stop of my PT109JP?, I could have a chance to enjoy an unusual REAL(not RC) boating for myself.!!! :-)) O0 {-) %% This was the very nice boating for me actually.!!!??? {-) {-) {-) {-) {-) {-)
Anyhow, an improvement has been continuing still now to get a better, stable and reliable lake-going RC boat. O0 O0 O0 O0
-
At least you kept on smiling {-) :-)) ;)
The new specification of motor/LiPo might be more suitable, I hope.
-
Yes, KV3200 was the smallest value among 3 alternatives suitable for the size of coupling hole...
With this specifications, less current draw is expected theoretically... and actually I have felt such an impression already in the
bathtub tests. O0 O0 Final test of the year on the lake will show the result which is to be held around the Christmas day. O0 {:-{ {:-{ {:-{
-
Hi mates,
I have enjoyed very much the 5th day of trial run on the very calm water nearly successful two days before, which were performed with newly made aluminum trimtabs and a new brand of brushless motors.
The result of the test run? is shown in the following pics rather than long wordy descriptions with no pics. Seeing is believing.! {-)
Here we go. !!
Pic1; So called a "quick crank turn" was a breeze.! :embarrassed:
2/3; Smooth sailing on a calm water
4;A long , powerful and white mass of wake shows the high speed condition. O0 :embarrassed:
5; Splashing ahead powerfully by the chine/bilge keel.! :-))
6; Stably turned.!!
7; Splashed aside neatly and powerfully
8; A mass of water came out of nozzles just over the surface by trimtabs and appropriate balance setting. O0
A cooling water drain can be seen subtly at the port side... O0
A massive and powerful water jet looks so impressive to me. :-)) :-)) :-))
9; A cooling water drain at stb side can be seen clearly. :-)) :-)) This is so important for a water-cooling boat, isn't it??!!
10;You did a very good job today with deeply drenched to the skin? Wow,Wow :-)) :-))
This is the final test on the water of the year and next is early Jan. as the above doesn't necessarily mean that there weren't any problems at all. {-) {-) {-)
-
If Jets were under the water might be better lot of thrust wasted
(https://www.modelboatmayhemimages.co.uk/images/2024/12/28/Capture.jpg)
-
On a hard chine hull with the jet outlets on a flat transom they should always be out of the water when planing. A properly designed planing hull should always have the transom clear of the water otherwise if water is curling round from the hull bottom up onto the transom it will be creating extra drag. Water jets are not screws, they are not pushing on the water but work by throwing a lot of mass (water) behind them as per Newtons laws of motion.
Jim
-
In addition to JimG's theoretical explanation, I have researched and studied some experiments ever done by some boaters as well as actual jet boats when I was thinking about where to set the nozzles level on the transom against the water surface.
From my trial runs, the water jet over the surface could give me some confirmation to be more excellent than semi-under water
jet propulsion. Top speed has become clearly faster than ever. O0
This is not a conventional type of screw propeller to thrust in the water, but a water jet propeller to thrust so massive volume
of water from the nozzle over the water surface.
-
Not on the Pibbers
-
Oh jaymac, you have a Pibbers don't you,? which I once wanted to get in vain since it was too late for finding it already in the market at that time... <:( {:-{ %%
Therefore, I decided to obtain such a jet boat as yours by converting Lindberg 1/32 PT109. O0 :-))
Well then, it's about the time to exhibit the video of the 5th trial run made with a powerful 3S lipo and brand-new brushless motors on a very calm lake. Those who are interested in the motion images of the trial run, watch it.
As a static pic already posted show, two jet water could be seen clearly come out over the water surface powerfully in the video thanks to the trimtabs that might have raised the stern up, especially at speed. :-)) :-))
Lindberg 1/32 PT109 with jet drive system sailed on a very calm lake powerfully. - YouTube (https://www.youtube.com/watch?v=yFBuosyV-5g&t=1s)
-
Hi fellow RC boaters,
It's been a very happy and fruitful year for me as to have enjoyed the RC boating and building throughout the year.!! :-)) :-))
It's totally and simply because I could have been healthy enough to have done such activities as the above.
For keeping a good health to enjoy and spend a wonderful time in any aspects of life including above, I have kept on practising
athletics including occasional swimming, not to say daily activity, but 7 through 10 times a month at the most. O0 :embarrassed:
I do intend to continue this habit until 90 years of age for Rc boating, not to say until 100 years.!! {-) {-) {-) {-) {-) {-) {-) {-) {-) %% %% %% :embarrassed: :embarrassed:
Here are my lovely queens and kings active on the water of the year.!!!! %% O0 :embarrassed: :-))
How about your queen getting along on the water?? :-))
Wishing you a very happy New Year to you all and your families from Japan.!! :-)) :-)) :-))
It's the New Year's Eve today. !!! :-))
-
That looks like a really good setup now, Kiyo!
I enjoy modelling very much as you do. Today we had the last sail for 2024 at our club pond. One of the club mates has an underwater drone and we found the submarine which got lost several weeks ago. The sub will be rescued in 2025.
Wishing you all a very happy new year which allows you to continue enjoyable modelling!!!!
Kindest regards
Arno
-
Arno,
A happy New Year.!!!! :-)) And thank you so much for sharing nice and unusual photos with us. O0
The underwater drone looks a practical and industrial machine developed to use for observing something in the water, doesn't it? judging from the image of the scope of the drone.. :o :embarrassed: And the image of the sunk sub looks so clear..
I am looking forward to having some pics of recovery operation as to how it is made actually...??
And it seems toooo cold from the pic of the observation image in which lots of shrubs beside the road were stuck with ice.!! :o
It's so amazing for me to have seen such an activity as to enjoy ? the RC boating in such a terrible conditions. :o :o :o
What on earth, how cold it was then there.....??? All of the participants might be so energetic to RC boating.... :o :o :-)) :-))
I was a bit annoyed by green algae stuck around the impellers shafts as seen in the pics and I removed them after coming home. The lake was unusually dirty with those algae on the 5th day trial run. :((
At any rate, let's have a wonderful boating and building as well as improving, repairing in this year, too!!? :-)) O0
Kiyo
-
If I should conclude the status quo of this jet MTB under development made so far, it would be as in the pics below at a glance. O0
Pic 1/2; Jet nozzles were set like these against water surface, namely about 2/3 high of nozzle diameter.
3; In the case of real missile boat of Japan navy. Nearly same as mine. :-))
4/5; Aluminum Trimtabs were set like these.
6/7; And a powerful water jet was thrusted nicely just over the water surface massively and totally.
8;To conclude, the boat has come up with a much faster and real runner on the water. :-)) %%
However, above doesn't necessarily mean that there are no problems at all still now, against which I am currently struggling to improve.!!!!!! {:-{ {-) O0 But it's worth challenging, mates.!! It's the very hobby, isn't it.???!!! {-) {-) :-))
"There is no royal road to model boating."'(Backerther said!) {-) {-) {-) {-) {-) {-)
-
Well said, Kiyo O0
Photo no. 6 looks very impressive, she is performing very well on the water!
Meanwhile I am still having a little amount of water ingress in my model. You told me, that you needed 7 attempts to fix the problem; I now have reached attempt no.5 {-)
Referring to your last statement: we will get there in the end!
-
Yes, indeed. We shall overcome whatever should stand in our way to success.!! {-) O0 :-))
Aluminum trimtabs are working very well to lift the transom up(or to refrain the transom down excessively)
And the tabs may have made the water surface around the nozzles so smooth and flat on which a powerful jet came out long
and low on the water, by which the boat might have been faster. If the jet was thrusted in the water, the boat might have been much slower. O0
"There is no royal road to learning"(an ancient Greek mathematician, Euclid said) :-)
while
"There is no royal road to model boating"(a current Japanese old man, Backerther said) {-)
-
:-)) :-)) :-))
-
I could have a nice weather yesterday to be able to ENJOY the Rc boating in the form of trial run that have amounted to 6th day of improvement test up to the day.
The weather was fine enough and calm to try the test run aiming at reliability on the water.
Through the test run up to today, the boat could be OK to run on the water in terms of good sailing behavior, its top speed and
sailing stability generally, not to say complete. :embarrassed: :} {-)
On the other hand, she is not necessarily reliable due to the motor itself or its selection, or cooling defect..
A water ingress at any parts of the hull has been blocked completely.
Judging from the above, it should need more months to resolve the above or to reach a compromise-able level of results, one or two months?
But it will be interesting and partly enjoyable for me to cope with such problems that will surely lead to a finally successful
model.!!!! :-))
Here we go with lots of pics of the test run as usual.
1; Typical splash at speed, neat shape of wave is impressive.! Awesome form of pic to symbolize its high speed, Wow !! :-)) :-))
2; imagine the high speed by the long drain water.!
3; At full throttle,!!!! :-)) :-)) The wake is looong and low as compared with those at low speed. Compare with Pic7.
4; The drains are confirmed clearly by this pic to come out at both sides.
5/6; At slow speed
7; Typical wake at slow speed raising like a rooster tail.
8; At middle speed
9; The pics show that powerful jets are projected clearly on the smooth water surface made by the trimtabs and hull. :-))
The waves of both sides have been driven clearly outwards by the bilge/chine effect neatly.
10; The same as above though this is at low speed.
Have you already made and enjoyed a New Year sailing, mates ? :-))
-
I made an analysis of status quo of the latest improvement of the boat as seen below.
Pic1;wake at slow speed with 3S lipo
2;Wake at middle speed with 3S lipo
3;Wake at top speed with 3S lipo in the latest trial run omJan05. The stern was clearly raised at this speed.
4;wake at top speed with 2S lipo in the 1st rial run. The stern was too low.
From these pics, it has become quite apparent that faster the boat, the longer and lower the wake is left behind the transom as a phenomenon. O0 %% :D
On the other hand, energy consumption of the lipo has become rapidly fast as the boat went faster, namely around 4 minutes at most if she should have run at higher speed as seen in pic3. {:-{ :o
While keeping the middle speed, she could enjoy the run time of 6-7 minutes. O0
-
I made a video clip as attached of the 6th day of trial run in which my PT109JP was running so powerfully than ever before
on a very calm lake. :-)) :-)) :-)) The video may tell all that she has done in the sailing test vividly even if a long wordy cordial
description was not attached any more in this post. %%
Lindberg 1/32 PT109 converted to a jet drive boat made a full throttle test on a calm lake. (https://www.youtube.com/watch?v=m7tMVr9uIhI)
Pic; "You did a very good job this time and a nice and safe return from the severe test." {-) {-)
-
Additional repot of the trial run of the day is as per attached below.
Pic1; Many waterfowls gathered to observe seriously, silently and curiously my jet boat to pass in front of them at speed. {-)
They were truly gazing at the boat.!!!??? %% :o How about your impression, Derek !? :D Stupid even to comment? {-)
2/3; On the other hand, a huge number of crows was doing the same on the trees, sometimes noisily among a few birds as if they were criticising my boat like " Oh it's so fast..", or " No, not so fast, we are much faster!!" {-) {-) {-) {-) {-)
4/5; This time, the water was so calm that cooling water drain was clearly taken and confirmed by my camera as being
done as expected to be powerful enough.! :-)) :-))
Yes, seeing is really believing in this point too, isn't it ??!! O0 :-))
The wakes, splashes and waves generated by this model boat do give me an impression and scale realism peculiar to a fast MTB. O0
One of the scale realism I feel from the sailing scenes is the very wakes, waves and splashes as well as its dynamics around the hull.!!! O0 O0 In this sense, not only scale details can afford to supply the model with scale realism, especially on the water, needless to say, if it's a really practical RC runner. O0 :embarrassed: %%
It should be likened to a well-dressed beauty walking on the pavement so uglily that does not match her static beautifulness nor
spoil her static charm. O0 :embarrassed: Haven't you seen such a beauty so far? I have often seen in the street and still now. {-) {-) {-)
The above is my own part of understanding from what I think a scale realism is in RC boating. O0
-
Hi there mates,!
I could find a very nice weather today and went to the usual lake for confirming the performance of the improved PT109JP
in terms of speed and reliability if she has become a really / practically serviceable RC fast boat on the lake. :-)) :-)) O0 O0 :D :D
The result today was so so. %%
I am attaching so impressive pics below of the test run reaching 7th day as trial.
As you may possibly feel something fast and powerful from the pics, she has really done an improved job this time as well, not
to say perfect to my expectation or image I have in mind... :embarrassed: %)
However, my camera woman has told me later that she was warned in the video monitor screen frequently as to be so fast to move the video-camera. O0 :D %%
I think the sailing performance and its scale realism of a scale RC (fast) boat could be judged to some extent by the wake, wave and splash caused by her, although my PT109JP is a fictitious boat. :D O0 :-)) %% Finally it was too cold even in Tokyo. {:-{ <:( ;D
-
When you posted the first video, the performance was not bad in my eyes. But when I watch the current video, you have improved it really to some big extent. She really looks very powerful and fast, just what you were aiming at :-)) :-)) :-))
-
Hi Arno,
I' m so glad to have your friendly comment and interest in the boat. :-))
Today I post the video for you as follows together with additional /impressive still images I took for analysis of the sailing conditions. :-))
PT109 jet-driven MTB converted from Lindberg sailed in the mid-winter powerfully and fast. (https://www.youtube.com/watch?v=wz3txJTucJg)
As you know very well, this kind of fast RC scale boat (though this PT109JP is fictitious) normally takes comparatively
long time to get it to run well as a serviceable / satisfactory model boat on the water...and unless having a successful result of a good performance on the water, the value of the model as an actual running RC scale boat might be diminished to some extent.
However, it could be worthy sufficiently of runnable RC scale boat to be kept in a room. :-))
Therefore, I have been repeating many times of trial run to make it looked a scale like Rc runner on the water, not like toy level of RC runner on the water. {-) O0 :embarrassed:
In such circumstances, this boat is still on the development stage and I doubt serviceable level of sailing performance may come before this spring... {-) {-) O0 {:-{ <:( <:( But promising too... :-)) :-)) :-))
A RC scale model had better be a RC scale model even/naturally in the sailing performance to match its good appearance, hadn't it..!!?? :-))
-
Hi
I improved the power train to gain more effective output and heat resistance of the powerful brushless motors by which I have thought that the reliability and speed will be drastically increased.
One of the improvements is a heat-resistant spacer to set between the motor and its mounting bracket of the jet pump unit.
This spacer is intended to contribute to a proper alignment between the motor shaft and the coupling, and the bracket has been damaged largely by heat through not a few of severe test runs at speed. <:( {:-{
In other words, I just rebuilt the mounting brackets for getting a correct alignment using the spacers. {-)
Anyhow, a brushless motor is really powerful enough to get the boat to run fast which is normally impossible to do by a conventional brushed motor.... O0 O0 O0 :o :o The motor I am using is 500W.
The spacer is about 1.0mm thick made of a metal and wood.
-
Well then, in the next place. I have changed my mind to stick to coiled water cooling style finally, though this coiled style is I still think very useful for the conventional brushed motor from my RC boating experience.
However, the coil jacket doesn't seem to have contributed largely to cooling in this kind of brushless motor which I have thought
is possibly basic cause of malfunction of the boat through many test runs.... {:-{ {:-{ {:-{
Therefore, I have set a pair of cylindrical type of water-cooling jackets as seen below.
The brushless motor is like a wild mustang at higher revolution.!! {-) {-) {-)
Instead it has contributed largely to high speed. %% %% %% :-)) :-)) :-))
I just feel as if I took a detour for cooling problem..... 8) {:-{ {-) {-) {-)
New spacers are also well fitted to the motor mounts. :-)) :-))
-
This time, I took countermeasures against subtle vibration of the motors especially at higher revolution, by setting motor supports
just beneath. I am generally reviewing the power system totally to see if respective part is secure for a fast jet boat.
The motors are installed very unstable on the vertical mounting walls with only two screws each briefly..... {:-{ O0 :o
On the other hand, the motor is like a wild mustang when in fast sailing.... :embarrassed: The screws are apt to be loosened to some extent comparatively easily. The powerful mustang has to be suppressed only to use the advantage of the power for a nice sailing boat, hasn't it.!! O0 O0 {-) :D :-))
With these supports, the motors have made more normal and tamely sound {-) with much less vibration. O0 :-))
I should have done such easy countermeasures earlier....But it simply came so as the options of countermeasures have been left gradually very few among which are these supports..... {:-{
-
That is looking good, Kiyo. Should I come across a similar problem, I would have to change the drive system to inrunner motors (at the moment I have mounted outrunners). The Kehrer system looks rigid though, using M4 screws. I am still fighting against water ingress, but was able to reduce that to an amount of only a few drops. If I cannot find the reason for that, I shall live with it. {:-{
-
Arno,
Thank you for always friendly comment. :-))
M4 screws may be quite OK to install such large brushless motors as yours, :-)) while mine are M2.5 !! to set smaller motors. <:( :-X Mine are cheap Chinese-designed/made :-X while yours are well engineered German-made?? O0 :embarrassed: {-)
I think there is no need deeply to worry about a few drops of water ingress which is so negligible small amount of volume for me unless solved. :-)) :-)) O0
By the way, additionally to reinforce the suppression of the motor vibration, I fastened the motors with a 0.1mm thick steel bands as seen below.
Through several countermeasures mentioned so far against subtle motor vibration and hellish heat, the motors have been GREATLY improved as if they were reborn, especially heat problem is done nearly perfect.
The revolution sound of the motors is like a music for my ears, not an irregular noise. {-) {-) {-) {-) :-)) :-)) :-)) :-))
The motors are easily touchable even after 6 minutes high speed run in the bathtub test.
In addition, electric consumption is also greatly improved to half in spite of two times longer run time than before which will be possibly incredible in general. O0 O0 :embarrassed:
This fact may prove to be improper setting of power train of the boat having been done so far. {:-{ :embarrassed:
These wild mustang-like motors seem to have become tame but powerful ponies. {-) {-)
Not hot but warm level of motor which is quite OK as the bathtub test, and it is promising to reproduce it again on the lake.! :embarrassed:
If so and the same is done repeatedly several times on the water, it is what I say is serviceable and practical RC boat on the lake.!!!! O0 :-)) :-)) :-)) :-)) :-)) :-)) That means truly success of this project.!!! :-)) :-)) :-)) :-)) :-)) :-)) :-))
-
I could have the best and very satisfactory time than ever in 8th day of trial run yesterday.!!!! :-)) :-)) :-)) :-)) :-))
The video will be exhibited later that may show you vividly how actually she behaved on the water. %% %% %%
I have just posted still images today of dynamic scenes of the jet MTB that will not be able to tell you exactly the dynamism
truly, though.. {:-{ {-) :embarrassed:
This is partly because of no sound and no movement, and such elements will contribute to represent the dynamism largely for us. O0
Since this is a RC running model boat on the water. {-) {-) {-) O0 O0
All the pics below is at full throttle level.
So, pay attention especially to the looong ,low and whitish stripe-like wake left behind the boat that will apparently appeal the very speed to us. ;)
I enjoyed this day 4 rounds of trial run successfully with no serious problems unlike previous trials made so far.
Each run time was about 5minutes due to battery capacity and very high speed.
This is, so to speak, the boat seems to have passed the entrance exam. imposed on her to become a serviceable and practical RC boat, though not graduated from yet.... {-) {-) :D
She has just really become a jet MTB literally.! :-)) :-)) Wow, Wow Wow!!
-
Hi RC boaters,
As I predicted yesterday about the video, I am so happy to be able to post it proudly as the following. {-) %% %%
The you-tube video will surely and exactly tell you how the boat behaved on the lake for close to 5 minutes with no cut. :-))
The full throttle scenes may come up from 1:30 past.
Lindberg 1/32 PT-109 water jet MTB sailed stably at full throttle.!! (https://www.youtube.com/watch?v=4idvkPvRRRQ)
Just comments on this sailing;
1:Acceleration is seen clearer than before firmly.
2;Motor sound is heard normally as the speed has gradually been built up.
3;Sailing behaviour is stable at speed which is partly natural though... O0 {-)
4;Actual run time exceeded 5 minutes easily keeping a nice speed to the end. :-))
5;The motors were a bit warm level after the sailing which was the largest and remarkable improvement.
6;No loosened screws at all.
7;A small spoonful of water ingress was found.....this is actually only one point to be corrected later. :embarrassed:
This ingress is thought to have taken place at full throttle speed judging from the prior test run in the bathtub...
This result of sailing is so compromise-able for a mere pla-model converted RC scale jet boat to sail on the lake in my understanding. :embarrassed: O0 :-)) Not to say perfect level, though. :embarrassed: :embarrassed:
Well then, enjoy (or enjoyed already? )the video of jet MTB sailing powerfully on the lake by the full screen of your PC.!!!
-
Very impressive, Kiyo :-)) :-)) :-)) I like the sound of the motors accelerating up to full speed! Sounds like music! {-)
-
Arno,
A great thanks for your compliment as well as joking comment. %% %% %%
Well, it's your turn to show us a successful sailing of superbly finished Shannon on the water.
I wish I could see the boat sailing gorgeously by the video in this spring at your(Kim's?) thread. :embarrassed: :-))