Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Navy - Military - Battleships: => Topic started by: Coastal on February 08, 2013, 12:49:11 pm
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Hiya, I was just wondering if anyone has fitted this kit ( out with three motors / props / rudders and if so have you any suggestions for motors to use. I believe the 63ft RAF ASR's all had three Napier Sealions fitted in them and i would like to try and get it historically correct if I can. Would I be right in thinking this would also be the same as the 63ft whaleback ?, I will build it as 130 as per the kit apart from that. Any help would be greatly appreciated !
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Hi, this link might be useful. Bluebird's build was not from a kit but it uses a triple motor installation. John (Bluebird) is a tremendous builder and very helpful. I'm sure his build will be of use to you. :-)
http://www.modelboatmayhem.co.uk/forum/index.php?topic=9758.0
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Thankyou for that ! I noticed his build was a larger scale , I was thinking of using the set up deans marine suggest and faking two extra prop shafts but adding three rudders instead of the one.. do other people ever do this.. or is it just me thinking completly in a different county !
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What do Deans suggest?
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Deans suggest a single Kestral Motor - single which after looking at the original drawings I am inclined now to agree with, the rudders and props would be pretty tiny if it were to be three props, all to scale and i doubt they would have any major power in them.. The motor set up they suggest is a Kestral 4.8 - 12 volt 5 pole motor ( 3amps), Marine 10 speed control ( 10amps ) and a 6 or 7.2 1.2amp hour nicad. Having been out of the R/C boat world for about ten years i come back to find pretty much everything has changed. I used to run everything on lead acid or Nicad, but there seems to be a complete abscese of nicads about now and the lead acids seem to not be about so much either.. I would prefer Lead Acid, i used to really enjoy the long running times on them..
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NiMh are only improved Ni cads, plenty of them about still, I always use them in 'smaller' models, Admitted runtimes can be a problem, but if you can shell out, there are some high rating ones out there. www.component-shop.co.uk (http://www.component-shop.co.uk/)
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I have seen twin motor installations with a centre trailing third prop and multiple rudders on a couple of sub 36" hulls - Italeri PT etc. Adding the centre/third rudder for authenticity will give the right scale look.
There would be less drag on this installation option does leave a central space between the motors for battery and equipment placement. Sailorboy's suggestion re a high capacity nimh battery stick will save weight and give more usable power than a heavy sla. This is a very light model and performance on single or twin motors will be lively.
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I had a good think about it all and decided to go for a SLA for the meantime if its running a bit heavy i will switch back to a stick pack instead. I have a large number of lights and various other fittings to add as well so the Lead acid will be able to run all my circuit boards as well to run all the extras. I think i will fake the other two prop shafts for display and leave a snub in the hull so they can be removed for running, same with the extra rudders. Although saying that I found out yesterday there were a couple built with just one shaft. they apparantly did not run very well.
Here is the three props on a later version, HSL189 this has the slightly larger rudders although from what i know they used the engines mostly to turn , by slowing or stopping one to create a turn.
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2007-08-16_174221_BMPT--HSL-189_zps90770aee.jpg)
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2007-08-16_100547_BMPT-130_zps7e719b6b.jpg)
(http://i1244.photobucket.com/albums/gg577/NWilkes1/729px-RAF_HSL_130_rescueing_Halifax_crew_c1942_zps13b731a6.jpg)
This is probably the best picture of them all though, an interior shot looking towards the bow. I was hoping to find some more but there seems to be a sad lack of them, and i cant find many books on the subject of coastal craft either..
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Forgot to post the picture ... duhh ..
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2008-04-01_185113_HSL156_INT_zps53dbce01.jpg)
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Hi Coastal
The BPC 63ft Air Sea Rescue Launch and the 63ft Whaleback are the same vessel, they got the nickname 'Whaleback' from their unusual shaped hull and deck which aided the pilots view forwards at high speeds.
They were extremely fast boats but suffered from 'hogging' which usually ended in a broken back or keel. The BPC 63ft Motor Gunboats were also based on the same design (also available from Deans Marine).
You've got some interesting pictures that I have not seen before but if you are looking for more try this website
http://www.asrmcs-club.com/boatswebsite/index.html (http://www.asrmcs-club.com/boatswebsite/index.html)
The following books for more pictures
Crash Boats of Gorleston: The Exploits of No.24 Air Sea Rescue Unit of the Royal Air Force During World War 2
The RAF Air Sea Rescue Service 1918-1986
The RAF Marine Craft Directories Vol 1 and Addendum 1 from the Small Craft Group
Air Sea Rescue During The Siege Of Malta. An Eye Witness Account Of Life With Hsl 107 1941-43- this about the BPC 64ft which preceded the 63ft Whalebacks but there are pictures of 107 with 63ft's operating from Malta.
Hope this helps and good luck with your model
Regards
Nick B
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Oh thankyou :) thats gonna be very useful, im slightly ocd about detail on things, do you have information on other launches as well, ww2 coastal MTB, MGB Raf launches and other small fast coastal craft are my main point of interest... dunno how i started to like them ! But then i don't know what possessed me and my husband to buy some real hovercraft either ! xx
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hi ya coastal
couple of suggestions for you - go with 3 brushless motors with Lipo packs then you will achieve lightness, which equals speed. You can also buy a gizmo from ACTion to drop the voltage of your Lipo main batteries down to the required voltage of the lights and other gizmos. Not sure if you have noticed but on the original boats all the props rotate in the same direction. If yu do this with your model as I did with the model I built yu will get a case of tail walking (where the boat goes to one side) and it is ever more present when the model is turned. They didn't have bigger rudders and if you have all three rudders working properly and have an independent speed controller for the two outboard motors, you should have no problem in turning the model. The person to speak to who has a great knowledge of these - is Christian cds123. aye
Christian may be busy but hopefully he will pick up on this thread
aye
john
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Thank you Bluebird ! I am gonna stick with one for this as its my first one building for a long time ( 10 years ish ) and i want more like it so the next one will be three props .. and motors.. ! I have written down what you wrote in my large book of useful stuff though ! xx
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Here's an earlier forum build of your boat which might be useful. :-)
http://www.modelboatmayhem.co.uk/forum/index.php?topic=33002.0
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Thankyou for that.. now that i have seen others i am back to thinking i must fit three props.. can anyone suggest a good set of motors ( not brushless ) please , considering the size i was thinking to use 400's although 3 of them may be to heavy and to powerful. I may have to make three rudders as well to match.
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After doing some reading, would anyone be able to tell me which of these four motor sets would be the best to go for .
3 x Graupner speed 400 7.2 volt
3 x Mtroniks Vision 400 Mk II
3 x MFA 385 5 Pole
3 x JP Power 400
In order to keep close to scale on the props i will be using long ( about 200 mm ) shafts and 25 mm 3 blade plastic props.( as close to the original i can go) the two outer ones running opposite directions and the centre one running right but connected separatly so i dont have to have it running all the time.. should allow slow speed operation and turning to be slightly easier. I will make the rudders by hand from plastic and set a brass rod into it as i build it.
Thankyou all for putting up with my questions and slight insanitys with having to have everything as close to exact as I can get it.. xx
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Hi Coastal, We're all a bit crazy on Mayhem but that = enthusiasm :-))
These motors fall into 2 groups. The JP Power 400 and Speed 400 suit 6 - 7v ish batteries, however, the remaining Mtroniks Vision and MFA RE385 suit 12v.
I think your choice of triple 400 size motors is ok but a decision on battery size/type will determine the motor choice and also the length of propshafts. The centre shaft could be shorter to allow the centre engine to be forward of the wing engines. The severe taper of the hull towards the transom/stern restricts space for mounting three engines in line using short 200mm shafts and it also means that the shafts will be steeply angled and this causes the props to waste thrust and lose efficiency. Its' important to keep the shafts mounted as horizontal as possible otherwise they are pulling water or 'wash off the bottom of the hull. Think of an optimum design e.g. an outboard motor where the thrust of the prop is horizontal. There's a lot to plan/think about but for me it's 60% of the fun/enjoyment. %) [size=78%] [/size]
It's also worth thinking ahead. I started with sub 36" hulls and soon after decided that I liked the advantages of larger models, up to 50". Like you, my main interest is coastal forces craft WW2 and later. I like to transfer motors/esc's and batteries etc., between hulls - its a lot cheaper in the long run although the initial outlay is higher.
You mentioned scale size props - the real boats had quite large props with a steep pitch and revved at under 3000 rpm. Their marine engines were high torque slow revving water-cooled aero engines - max 2000 revs approx. :o
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Thankyou for all your help ! I will be using m troniks i think i would prefer the 12 volt system more , it works with all the other electronics thats going in it ... and my interest is in exactly the same area as yours The RAF boats although i also love MTB's and MGB's as well. Its having a lead acid fitted in , i did a quick weight check rthe other day and figured going on the published weights for all the parts as long as i fit it as i worked it out it will be fine ! I also brought the book someone suggested on this the other day hopefully that will turn up soon ... More nightime reading for me, getting bored of my romance novels again anyway.. they are just not technical enough ! xx
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On 12v the Mtroniks Vision 400 would also be my choice.
This clip is Part1 of 4. :-) www.youtube.com/watch?v=vILmR-xLZNQ
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Cool theres some great old footage in there ! thanks for that and thanks for your help, I will be posting pictures of the build when i start that at the moment i have a Faux RAF launch losley based on ST441 its because i had a old abs hull in the garage thats hull very closley matched the hull shape of the ST's. Its a bit longer ( 51ft in stead of 41'5 ") but im scratch building that using the prop and shaft and partially the rudder from Deans marine 63ft whaleback kit. The extra length will enable me to fit it with one rear fixed gun into the lower deck area. Its only losley based on the 441 so it will be pretty different towards the rear end.. Im going to give it an X number and pretend it was a craft built as one off. I can post pictures of that as well if people are interested. !
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Sounds good, post some pics of both. I'm assuming the 12v sla battery is the large 7amp/hr. I f so, then the forward edge of the battery (placed lengthways and on it's side) should be sited approx 12" - 13" measured from the bow for planning/layout purposes. I know this may feels too forward but when the hull planes it will carry this weight and it minimises the alternative problem of burying the narrow stern and having the hull 'snow ploughing. On testing the hull you may need to adjust it either way - even small adjustments can have a huge effect on trim and hull behaviour at speed.
This heavily tapered BPB hull is problematic since it has quite a small wet area relative to the deck area and the hull's weightbearing abilty is generally less than it first appears. Once this hull planes the wet area is smaller again.
One of my hulls is 49" and it planes beautifully carrying two of these batteries. I could not get it to plane at first and I experimented by siting the front battery further and further forward and the hull finally lifted onto the plane and flew. I was amazed - I've learnt more from that hull than I will from any other. This abs hull sounds interesting - how long is it?
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Hiya,
Its 25 1/2 inches in length, Ive fitted the base structure inside fitted the prop shaft and rudder tube filled and sanded the hull til its perfectly flatand put the deck on , yet to cut the deck holes out yet !
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2013-02-12003135_zpsc3b31137.jpg)
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2013-02-12003223_zps23436621.jpg)
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2013-02-12003238_zps1dc70af4.jpg)
Thanks for all the battery info there as well ! this is all extremley useful for me !
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Not the deans Whaleback kit , my Faux version of an RAF boat instead still in 1:24 scale just a self designed Seaplane Launch... Carrying on from yesterdays post for Perkasaman who asked to see !
The whole hull is aprayed grey to allow me to see any minute areas of problems that i need to solve, with fillers and sanding. I have built an entire wooden looking front end onto the craft to allow it to have some air of realism, deck cut and added side stripping added. There are a few little areas i will need to rub back and continue on the filling work with, but until the hull is perfect i wont start on the top sections.
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2013-02-12160254_zps21db2263.jpg)
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2013-02-12160317_zps0feb0bbc.jpg)
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2013-02-12160330_zps1ee06683.jpg)
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2013-02-12160346_zps2a8605fc.jpg)
Hope this is of some interest to you !
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Please note that my guesstimate of your kit hull being able to carry a 12v 7 amp/hr sla was not of this planet or any other. I weighed one of my 'bricks' and it's almost 6 lbs! Sorry for the error - a more appropriate sla for this hull would probably be the 12v 2.6 amp/hr - max. As a guide I am using a scale displacement target weight for the model of about 4lbs max.
Looking at your excellent pics I think your abs hull will easily pass for the Seaplane Tender, especially the bow - it looks absolutely right. the length and beam proportions are close enough -well spotted. :-)
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Here is some Pathe newsreel of the boats in a wartime publicity film:
http://www.britishpathe.com/video/raf-rescue-boats/query/RAF+rescue+boats (http://www.britishpathe.com/video/raf-rescue-boats/query/RAF+rescue+boats)
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Coastal it would pay you to read my article in the painting section and pay particular attention to the guide coat before rubbing down ;) ...It will show up ALL the bits you have allready missed
Dave
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Thankyou Stavros i will do just that! :). Thought id post somemorepicturesof my faux STfor you all to see..It needs dusting a little, the first two Square LED's have been added into thier troughs, and the whole section clips in to place.
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2013-02-17192656_zpsd9135c92.jpg)
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2013-02-18033551Copy_zps0592cd04.jpg)
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2013-02-18033551Copy_zps0592cd04.jpg)
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2013-02-18033644Copy_zpsb70b63e6.jpg)
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2013-02-19122001_zps2e702493.jpg)
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2013-02-19163525_zpsf5739052.jpg)
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2013-02-19163525_zpsf5739052.jpg)
(http://i1244.photobucket.com/albums/gg577/NWilkes1/2013-02-19163525_zpsf5739052.jpg)
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Your fabrication work on the ST is impressive and you are making rapid progress with the build. I like your slot-fix interior and everything fits together snug. Usually the deck opening has a quarter inch high raised combing around the edge to deflect spray from entering hull openings but this design has a single large opening and this gives a very useful one piece cabin/rear 'deck well' with removeable cabin roof. I think that spray entering the forward cabin is unlikely to be a problem in calm weather sailing. This is lovely work - your design and use of materials is superb - excellent fit and finish. :-)
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Thank you Perkasa man, To differentiate my invented craft from the real ones, I have added a higher cab, I am intending to make this an engineers ST, so it will be substantially different in many places, It also allows me to load it with tools and stuff, The thinking is if it was real it would have a lower cabin down below the cab and in the bow. Ive cut the basic windows out now, these need there inner surrounds and frames added which i will make shortly, but wont add untill i have sprayed the top section up. I still also have to add the roof edging , hand rails, roof detailing and such.. long way to go yet!
Lighting circuit board with plug n play led system...
Basic cab structure- with 1/24 scale man showing the elevated cab design.
Still got to add strengthening frames to the windows on the inside..
Hope you all like !
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Coming along very nicely, especially like your wee man
cheers
vnkiwi
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Great work as always
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Hey Coastal, very clean build you have here, well done. :-)) I was wondering about the lighting circuit board with plug n play led system. Will it work with a 12 volt system? Any info on that would be greatly appreciated.
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Hiya
Its all made for a 12 volt system as thats all that i use, nearly always 12v lead acids... !
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I will be doing a full write up on the one for my Deans Marine Whaleback shortly that has a complete lighting and systems board going in it. please find that thread here - http://www.modelboatmayhem.co.uk/forum/index.php/topic,42257.0.html (http://www.modelboatmayhem.co.uk/forum/index.php/topic,42257.0.html)
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Hi Coastal quality build so far! O0
I have some LED's for idiots questions if you dont mind answering? %% Basically, i want to put some nav lights on my build. Is it pretty straight forward inserting an LED circuit board and can you suggest a supplier? :-))
Thanks Mark
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They are easy enough to make, you just have to make sure you have the right resistance, pm sent to you !
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Thanks, I will keep watch for your write up on this. I use leds on my boats but they come prewired with the resistors on them . I am trying to find a way to eliminate some of the wiring for my lights. On my last ship I had some 50+ leds last counted, alot of wires, all wired to a power distributor for 12 volt system.