Model Boat Mayhem

Mess Deck: General Section => Beginners start here...! => Topic started by: BroomBroom on March 13, 2009, 11:52:29 pm

Title: Greetings and RC Retro Conversion Help Needed!
Post by: BroomBroom on March 13, 2009, 11:52:29 pm

Greetings all...

Been browsing around and this looks like the place to be! I see there's a huge amount of collective knowledge here and I'm hoping some kind souls can point me in the right direction with my modest project. Just so you know, this is my first model boat - but - I have restored/rebuilt quite a few full size jobbies and have a long history of RC Aeromodelling.

Anyways, I recently picked up an old Aero-naut kit - 'Forelle', plans dated 1959.This was originally designed for a small electric outboard and no RC. It is made of ply/ply sheet and is small and light (Length 340mm x Beam 118mm).
Very much in the style of the earlier Chris-Craft/Riva type launches, the lines are fairly simple and it has a very flat bottom (with a 'fin' - yet to be installed). The build so far has been straightforward enough and I'm pleased with the way it's coming together.

OK, that's the background, here's where I could use your help please...
I've decided to tweak the original design slightly and built it as an inboard, electric, RC model. This is a whole new area to me and I have the following questions:

1. Given the small size and weight, what sort of motor, mount, batteries, ESC etc. would I need?
2. What do I need and how do I go about configuring the prop shaft - and what size prop would I need?
3. What size rudder would you reccommend and where does this get itself positioned in relation to the prop?

If anybody chimes in with a list of all the bits I need, that would be awesome - and I'll obviously keep everybody up to date as the build and installation progresses. I'm not looking to turn this into a rocket, just some nice scale speed cruising on calm waters (but I guess it would be nice to get her up on the plane at WOT).

Many thanks for any assistance you can offer and let me know if you need any further info.

Cheers,

Robin
Webmaster/Forum Admin - CMBA (The Classic Motor Boat Association)www.cmba-uk.com (http://www.cmba-uk.com)

(http://www.starguitars.co.uk/broom/forelle1.jpg)

(http://www.starguitars.co.uk/broom/forelle2.jpg)

Title: Re: Greetings and RC Retro Conversion Help Needed!
Post by: das boot on March 14, 2009, 11:31:27 am

Robin, the man to answer all your technical stuff if our very own FLJ(aka Full Leather Jacket)he makes all this sort of stuff and is a wizard on motors, esc's, etc.
Have a ferret round for one of his posts and then PM him, he'll be back to you pretty rapid.

He sorted me out with motors/esc/loads of advice for my Mighty Mo(a Tamiya USS Missouri conversion)

Good luck with your project, keep us informed as to how it goes....and welcome to the madhouse, by the way!!!

Rich

Title: Re: Greetings and RC Retro Conversion Help Needed!
Post by: Proteus on March 14, 2009, 12:39:39 pm

Mtroniks do a nice brushless combo for that size of boat  "Hydra15 combo" it's not on there web site but it is on the newer model mags nice and small and waterproof should make it go well.
you could use a metal 380 mount or even a ply bulkhead at an angle and the motor bolted through, prop shaft try ASTEC they do a nice 2mm SS shaft that will take M4 props I would contact Mtronics for the recommended prop size , and rudder is more experiment to see what works if you get one of the small rudders from the likes of SHG who will also  have the couplings (see advert at bottom of page)

http://www.astecmodels.co.uk/catalog/product_info.php?cPath=1_90&products_id=621

Proteus

Title: Re: Greetings and RC Retro Conversion Help Needed!
Post by: BroomBroom on March 17, 2009, 08:46:08 am

Many thanks for the guidance chaps, I will seek out the jacketed one...

Hull now sheathed using tissue and West Systems epoxy - because of my 'full size' projects, I'm lucky enought to have a shed full of boatbuilding materials. Will remember to take pics as things progress...

Cheers,

Robin

Title: Re: Greetings and RC Retro Conversion Help Needed!
Post by: andrewh on March 17, 2009, 09:17:39 am

Robin,

You won't go wrong listening to FLJ :}

And I may be able to offer a bit of my recent experience in this size of boatlet
This is very close to the Brushless trial boat I made  - cos I made a Footy hull (305mm) and powered it with both a home-made brushless motor (CD-ROM motor, 2208-11) and a bought (cheap) bell motor (2509-21)  both on a cheap 10A brushless speed controller.
pics and video clips at
http://www.modelboatmayhem.co.uk/forum/index.php?topic=14068.0
Please don't worry about the silly bow-up attitude - this is a model yacht hull with a lot of rocker - yours won't do this
Running gear is a 2mm prop shaft with Graupner 2mm 29mm dia carbon prop (george turner)

The conventional motor alternative would be a speed 400 (any voltage) or even better a S300 :-)) running the same prop and driven by either 6, 7 or 8 high capacity AA NIMH cells (or a 2Sor 3S lipo since you are an aeromod bod).  My favourite would be the S300 which has a splendid KV and will really twist this prop.
For info, your hull is about the same size as the S400 racing boats, so all the hardware and preformance is well known

If you wanted an outboard option  - but not a fast one -  I shrank a Seagull (by repeated hot washes)
(http://i222.photobucket.com/albums/dd159/andrewh_photo/Harry/DSC04512.jpg)
There is also a family of outboards which are found on cheap toys - they have a 3V Mabuchi 140 directly driving the prop, and work very well on 6 or 7.2V for rather more exciting performance :}

The Hydra 15 that was mentioned may be a little large for the boat, but since Mtronics publish no data and no-one has admitted to owning or running one we are guessing.  (Normally the figures "15" mean "equivalent to a 0.15cu in (3cc) glowmotor" in motorspeak.  Speed 600s are known in the US as "05" 1.5cc equivalent)
andrew

Forelle is trout in german - hope you are going to put spots down the side :}

Title: Re: Greetings and RC Retro Conversion Help Needed!
Post by: BroomBroom on March 17, 2009, 09:47:28 am

Andrew - thanks for your input - loads of good stuff there that I can spend some time checking out!

I was originally going to go down the outboard route but I kept looking at the thing and thinking 'something don't look right'. Couldn't put my finger on it until I realised that as a 'semi-scale' jobbie, it followed the typical layout of a two seater with inboard engine under a lovely big engine cover... erm, with an outboard on the back of it - hmmmm. Hence my decision to go inboard (I've got an old Seagull in the loft - in bits. A future project is to take it to the tip :-) )

Yup, I researched 'Forelle' but sadly I cannot bring myself to paint spots on it, but I like 'boatlet' so I may call it 'Troutlet'  {-)

Thanks again,

Cheers,

Robin

Title: Re: Greetings and RC Retro Conversion Help Needed!
Post by: andrewh on March 17, 2009, 12:27:59 pm

Robin
Robin

Quote from: BroomBroom on March 17, 2009, 09:47:28 am

(I've got an old Seagull in the loft - in bits. A future project is to take it to the tip :-) )

Yup, I researched 'Forelle' but sadly I cannot bring myself to paint spots on it, but I like 'boatlet' so I may call it 'Troutlet'  {-)

Please don't throw the Seagull away - they are inherently indestructable and even considerably manky parts are useful.  I have a Finnish friend who runs several of them on a lake waaaaay to the east of Finland - he might be interested in the bits

If you do go brushless, and know some very clever pic-programmers, you could arrrange arrange for the motor to actually play "die forelle" as you cruise.  For speed work you might need sommat like "bat out of Hell" or "the ride of the valkyries" :}

please show us the progress
andrew

Title: Re: Greetings and RC Retro Conversion Help Needed!
Post by: Proteus on March 17, 2009, 03:04:44 pm

if you need bits

http://www.saving-old-seagulls.co.uk/

the gulls drive you mad

Proteus

Title: Re: Greetings and RC Retro Conversion Help Needed!
Post by: BroomBroom on March 18, 2009, 12:01:38 am

Got immediate advice from FLJ  and I'm gonna take it! Will post pics as the build progresses but have some work to do on me 1:1 scale boaty while the weather is good :-)

Don't worry guys - I wouldn't really scrap my old Seagull - it's in fairly good (albeit dismantled) shape. One day I'll get her up to scratch and move it on to someone who will love it  :kiss:

Thanks again for the warm welcome and sage advice,

Cheers,

Robin