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[Circlip]

Hope to be proved wrong Backerther but I feel the positioning of the water 'scoops' are optimistic to be effective.


  Regards   Ian.

[Backerther]

Hi Ian;


Thanks for your interesting comment.
I do hope everything should be Ok different from your observation.
It's hot in UK the same in Japan as well.!


Kiyo

[Backerther]

Hi all;
I set the water cooling tubes roughly as shown to see how they go inside the hull and the result is so-so.
It seems no possibility to kink even in the fast and rough run perhaps with some adequate fixing measures to secure them.
Well,most parts required to RC operation seem to be ready fundamentally and I may be possibly get into practical assemblies
with adhesives for permanent fix of them.

[frogman3]

NICE work Kiyo on your mtb but i see your motors are not linein up with your prop shafts or is it because you havnt glued in the motor bulkhead yet ?
chrisb 

[Backerther]

Hi Chris;
Thank you for your comment.
No,I haven't glued the bulkhead mount yet.
I have only glued the prop shafts up to this day as I have been preparing some parts for RC operation.
But I feel it's about the time to fix the parts permanently as most parts are already ready for the actual assembling.
Are you OK with hot weather in UK as weather reports here in Japan have broadcast worst conditions generally
across Europe nearly every day..!!? Especially in Spain...
Stay safe against hot weather and covid-19.


Kiyo

[Backerther]

Hi all;
I started essentially fixing work of the parts already prepared up to this day.
First of all,stern tubes I think should come first for starting anyhow.
1;stern tubes glued precisely located.
2/3:Bottoms of grease tubes were also glued to the hull bottom to reinforce both the grease tubes and stern tubes.  
    This will be a part of auxiliary support for the stern tube.
4/5/6/7:Main supports for the stern tubes were made from a stuff found in the odds and ends and fixed,by which I think them well kept for continuous high speed running on the lake,perhaps..

[Backerther]

Hi all;
At last,I have come to so important stage to glue the bulkhead motor mount permanently in the hull.
This work is so annoying and troublesome to me as the mount has to be precisely glued to align with two prop shafts.
This boat is intended to run fast continuously in each run, not to say at full throttle all the way.
1;I eliminated sharp edges of the bulkhead to make ditches of two -part epoxy flow along the ditches.
 This work was also done on the opposite side.
2;I just glued the bulkhead temporarily to check if the motors/props should run properly before greasing the stern tubes
   for the slow-test run.
3;Parmanently glued after brief test which I judged fundamentally OK
4;I painted brass color at the joint parts of grease tubes for a good looking.
5;I also tested to know how greasing would be easy or not over the deck. so-so..
As a result,the mount was securely and rigidly glued in place.

[Backerther]

Hi all;
After fixing the bulkhead mount in place permanently with intensive check of precise location to be in line with the screw shafts,
I made a test run briefly of the core parts for the fast RC runner to see if the core should work properly.
The points of the test were if the motors should work naturally,calmly,smoothly with no peculiar noise as well as the same values of RPM between the two motors.
I did the test only using 1.2V NiMH AA battery together with a tachometer that I have been using for RC planes for many years.
1;The core of this boat is now ready to take a brief test after a slight adjustment on a left motor location,though inclination angle of the bulkhead was nearly perfect to set.
2;The tachometer is set.
3;Left screw showed fundamentally this value,sometimes showed 2000RPM,sometimes 1800 and mean value is 1900.
4;Right screw 2000 RPM of mean value....
5/6;The core is ready at last.!!
The sound of the revolution was very calm and smooth as if no load had been born and like a flying mosquito.
Oh !,yes,this is the mosquito boat,isn't it??

Without this good result,I could not go further ahead to build. But I am in a laughing mood currently with this core parts.

[Backerther]

Hi all;
The core parts were successfully built in as in the preceding report.

In the next place, I set the fore and after platforms for radio gear permanently though it was done just two-sided adhesive tapes,though tough tapes to fix.

Non-slip rubber sheet was glued with the two-sided tapes here too together with rubber bands,both of which are good combination to fix the battery firmly in place even when in running fast on the water.!!
I like this combination very much as it is simple,secure and easy to fix and relocate the stuff like a battery often used as a ballast.  

[Backerther]

Hi all;
This is a water cooling system which I do think is essential to equip for my PT-109 to run fast with Mabuchi 540s fundamentally all the time on the water like a real MTB.
1;water inlets fixed with epoxies.
2;water cooling tubes attached to and bound around the inlets firmly. If these should fail,the boat would soon get to the bottom of the lake within a couple of minutes without doubt. 
  The same thing could be said in other points of the cooling system.
3/4/5/6/7/8;All the cooling system is now complete.

[Backerther]

Hi all;
In the next place,I set the rudder connected parts as shown.
1;Rudder helm adjustment with some aluminum sheet
2;Tiller arms and link
3/4;A rudder servo installed with two-sided tapes firmly on the vast platform.
5;Overall layout of the rudder system
6;Around the rudders

[Backerther]

Hi all;
I am so happy to announce that all the drive system seems to have been installed properly and fundamentally in place this day. The rest of work will primarily be a pla-modeling which is fundamentally not my likes...
Two motors rotated properly at very low voltage like idling speed,however I did not try middle or hi speed run this time on the table for the important motors.
Both rudders moved the same amount to each side at sufficient angle.
However,more or most important is the very seaworthiness on our local lake where she is supposed to sail at fast speed from this autumn regularly,because she is just 30 inches long with low freeboards....!!
I am expecting her to be a good runner with draining cooling water powerfully on both sides in our local lake...

[RST]

Hope to be proved wrong Backerther but I feel the positioning of the water 'scoops' are optimistic to be effective.


  Regards   Ian.

Hi, my my Perkasa ran with similar pick-ups like that for years -no problem at all.  Since then I've tried to use the correct motor /esc for the job in the first place, but Backerther seems to want a belt and braces approach for or all the hassle of tubing and extra weight not really needed if it's sized right first.

Rich

[Circlip]

Yep, it's an old fart thing. I always preferred to know the water was circulating through the system with the prop turning and the boat restrained rather than splash and dash and fingers crossed    Many roads to Rome, advise is freely offered but in the words of Dave M (FLJ) suit yourself.


  Regards  Ian.

[Martin (Admin)]

There's some very interesting thoughts about cooling model boat motors in this video, see what you think!

https://youtu.be/IXMwwzGGbOM?t=211

[RST]

Hi Iain,

You must be coming from the old days of IC engines when you need cooling when the engine is idling -you don't need it on a motor unless it's running hot at full-chat.

More alming thse days I've seen a few folk using the horrid plastic water-scoops just because they think someone designed it for a purpose so it must work.  rather than just an inch of brass tube cut at 45 deg.  My Perkasa used to go like "s**t off a well oiled shovel" all those years ago.  I've not sailed my 1:48 PT boat for a while but it couldn't really go any faster on a single 400 size motor on 7.2v without looking stupid.

...anyhow sorry Backerther we're detracting from your build!

Richard

[Backerther]

Hi Rich;
Don't worry about that at all.!!!
Each person has his own experience,thought and opinion,etc about his modeling and sailing.
Even I have experienced RC modeling for years through and upon which I am currently enjoying RC boating.
Each modeler has his own style as to how he should successfully build his model through his ideas partly from his experience.


By the way,your Perkasa looks awesome on the water.
Are you sailing the boat currently ? I would like to see her sailing in here!!!


Kiyo

[Backerther]

Hi all;
Building process is moving on to the decking from today.
As for this process, water-tight is very important since especially this kit has large gap all around the detachable deck in the main deck.
It seems water will soon come into the hull so easily during the sailing on the water, as the detachable deck or boat itself must be always exposed to continuous splash by the speed!!
I glued additionally lips all around the inner edge of main deck expecting water-tight and tidy fit of detachable deck...
1/2;Additional lips added
3;Viewed from top
4/5;Breif test of water ingress though I did not expect a good result in this level of counter-measure.
6;The first test was OK...
7;The second test after one minute of "splash?" ..no good..as I imagined previously
The real enemy of Lindy 1/32 PT-109 might be water ingress around the deck...???
To be continued for the counter-measure now under construction in a very routine method...

[Backerther]

Hi all;


The second trial work of water leakage counter measure was done in the manner as shown in vain.

[Backerther]

Hi all;
The third counter-measure against water leakage is to change the water seal rubber and to add magnets to fix the inner
deck firmly in place,by which I intend to get a better water-tightness.
And the test is supposed to carry out after decking work is finished since it will be more practical,useful and meaningful to do.
1;Magnets fixing parts
2;New rubber seal
3;Very very old magnets found in my odds and ends box
4;Under assembly
5;Assembled
6/7;Inner deck set flush with the main deck more neatly,tightly and securely than before by the magnets, which itself will be of some assistance to the water tightness,perhaps.

[Backerther]

Hi all;
It seems high time that the deck was glued permanently on the hull,since everything appeared OK through the final checking work. I used 90 min.epoxy adhesive for the better adhesion though that requires about a day complety  to cure.
But,I intend to spend about two days for curing this time.
1:Underside of the inner deck was checked.
2;motor rotation,rudder movement,rudder servo installation,fixing the water tubes especially around the rudder posts,etc..
   checked seriously.
3;Ready to go.!! wishing a good result on the work.!!
4/5/6;And done at last !!
  Wait for two days.!!
 

[Backerther]

Hi all;
I released the taping from the hull and shaped it up neatly for the painting work.
It is about one month since starting the assembly of Rc conversion of the pla-model boat scheduled to finish
at around this September.
It might be going on well on the schedule....and could be OK to make a maiden voyage on the lake ..??

[Backerther]

Hi all;
I made a balance test in the bath tub to know how the boat may sit on the water though all the structures on the deck
were not fixed yet but it is coming to the completion except painting. And all the crews and 20mmAAG are not on the deck at the test.
The result is so so at this stage. 
1/2;This intermediate balance test was made with this condition.
3/4/5/6;1 cm above the water line at stern. Of course,water outlet is sufficiently high from the water line.
7;The battery couldn't help being moved to this location to get the balance leaving a large vacant space... 
  Though this was expected previously to some extent.

[Backerther]

Hi all;
I have just forgotten and noticed very important stuff to add to the hull..Actually real boat was really equipped with..
That is bilge keels along the chines.!!!!! So far as these are important in terms of not only rolling stability, but also seaworthiness and scale realism.
Especially,these bilge keels for a small boat like MTB will play a role like spray strips on the water contributing especially to better seaworthiness on the rough water largely.
Therefore I am trying to add the keels currently.
1/2/3;Under study how to get a good result of work...
4/5;The bilge keels of PT-109 are very similar to those of my Jupiter F-99 cruiser very much.The waves were driven out of the side by the bilge keels apparently...even on the rough water.
      And I expect a good effect on the water to my PT-109 as well....
6;My first PT-109 was not equipped with the bilge keels,by which the waves out of the hull bottom stood like walls along the free board....The boat was soaked with the water thoroughly right away even at low speed..!!
7/8; The chines of this Najade were well contrived and shaped to drive the water out right aside from the chines..good cruising characteristics.
9;Even this 55 cm mini-Jupiter P550 has a good shape of chine to get the water out aside the hull making nice wakes.though without the bilge keels.


From the points of views mentioned above,I am trying to add better bilge keels to get my PT109 to run at speed on our lake.

[ScottW]

Although the immediate topic is technical stuff, that view looking at starboard bow of the one with green cabin roof, that is a nice image of a pretty boat.