Barrel Back….

[Phil Winks 1Participant @philwinks1]

the motor is one of a collection I’ve got from my rc car racing days and yes the limit of the motor is huge however I must point out that rarely would I expect to get to that figure as the heat generated is also huge and even a good water coil around it would struggle I suspect when it was in a car it had forced air cooling and even at full chat from stand still it only drew 50 amps thats why cars only race for 5 mins on a 3300 to 4500mah bty just nice to have a big reserve helps preserve the motor eh

[Phil Winks 1Participant @philwinks1]

Another question for those in the the know as I plan to power my copy of pauls launch with 2 props would I be best fitting twin rudders too so as to getthem into the prop wash to allow better controll at slower speeds?????

[Paul TParticipant @pault84577]

Phil

 

With twin props it is best to fit two rudders and given the long and flat bottom of the model it would be better to fit oversized units to give better performance at low speeds.

 

Paul

[Phil Winks 1Participant @philwinks1]

Cheers paul thats confirmed what I was thinking I’ve located some that are 63 deep x 35 at the top and 25 at the bottom I reckon these and fins forward of the prop shaft exit point should help some plus obviously the props are to be contra rotating just one point how does the best part of £8 per 30mm 3 bladed brass props sound ? is this about right or should I be able to find cheaper the shafts are only a fiver each and have stainless shafts washer and nut from good old fleabay

[Paul TParticipant @pault84577]

Hi Phil

 

£8 is slightly on the high side but if they fit the bill then there’s no problem, I like good old fleabay and buy quite a few bits from there, including a brand new 40mhz 4 channel transmitter for 1p (plus £6 postage) not bad eh.

 

When are we going to see some photos of your build?

 

Paul

[Phil Winks 1Participant @philwinks1]

I’ve beeen holding back on starting a thread till I am ready to start work proper. I do like to prepare  however as I’ve got the power plant sorted today I’ll start the thread today

[Paul TParticipant @pault84577]

[Phil Winks 1Participant @philwinks1]

Those seats look good enough to sit in Paul lovely job. I should have a shed full of bits of boat frame to photograph by the end of this coming weekend fingers crossed

[Paul TParticipant @pault84577]

Thanks Phil

 

Believe it or not they are the product of 6 weeks work and countless cockups. At one point I threw them away and started to build a varnished wooden set but Jane would not let me give up.

 

The seats have a mdf core and wadding as padding below the red so they do perform just like a real bench seat.

 

Paul

[Bob Abell 2Participant @bobabell2]

Very nice, Paul

 

With the soft underlay…………….they`re crying out for a few red buttons???……….If you`re brave enough!

 

Bob

[Paul TParticipant @pault84577]

Hello Uncle Bob

 

The buttoned seats were version 14 they looked nice but the seat covering kept splitting so I binned the idea.

 

I bought 2sq m of material to make these seats and wasted most of it…I dont envy the people that make chairs for a living.

 

Paul

[Paul TParticipant @pault84577]

The folding windscreen is fitted.

 

[ashley needhamParticipant @ashleyneedham69188]

Exquisite. 

 

 Ashley

  (nb, it will look very silly without a driver and dolly bird. )

[Phil Winks 1Participant @philwinks1]

Ashley’y right Paul truly exsquisite.

[Paul TParticipant @pault84577]

Good Morning Bob

 

You are up bright and early today.

 

In answer to your question I have got an engine for the barrel back, I am sticking with the Ripmax IC starter motor and using 2:1 gearing to up the revs.

However I am also thinking about adding a couple of scratch built waterjets to increase the speed.

I am sat looking at the stern of the boat which has two 1/2 inch exhausts just above the water line these could be used as jet pipes (no good for turning but faster on the straight)

 

I will let you know how the thought process pans out.

 

Paul

[Bob Abell 2Participant @bobabell2]

Water jets ABOVE the waterline…………………..eh?

 

Bob……………Confused

[Paul TParticipant @pault84577]

As the pipes exit the transom I would angle them slightly downwards.
Dont forget that they are on the waterline when the boat is at rest but when the boat is moving forward the stern will settle and the pipes will be submerged.

 

The engineering to produce the jet units is basic and if they are powered by a pair of 600s I should get a reasonable turn of speed the only problem will be turning the beast as the single rudder might not cope.

 

But I am still thinking   

 

Paul

[Bob Abell 2Participant @bobabell2]

You may find, the jets will be squirting into the stern cavity?………………..But a good squirt coming out back will look impressive anyway!

 

Bob

[Paul TParticipant @pault84577]

You could be right Bob but it won’t matter as the jets don’t have to be under water for them to work.

 

This is a quich sketch of what I am thinking of…using some basic plumbing fittings, cheap plastic props and a short shafts.

 

.

Sorry for the poor image (its slightly better if you expand it)…..the CAD doesn’t like saving to jpeg but you get the idea.

 

Paul

  

Edited By The Fat Controller on 03/05/2009 08:10:01

[Paul TParticipant @pault84577]

This is a better image when viewed on the album section.

Paul

[Bob Abell 2Participant @bobabell2]

Not thrilled with your jet positions, Paul……………better underneath?…….or not at all, Paul!

How about a Cort nozzle in place of a rudder?

 

Bob

[ashley needhamParticipant @ashleyneedham69188]

I am thinking that  retrofitting waterjets in their normally accepted positions would be difficult as the hull has been almost finished? and so the tube exits, which would look impressive but possibly a bit out of character? A better bet might be to stick simply two more wing shafts as per normal on the boat or is that also too difficult? ashley

 

Or, the really fast boys use those flexible shafts, and using them might give you more choice on where to fit the motors?

 

Or a forwards facing prop at the front !!!!!!

[Paul TParticipant @pault84577]

Bob & Ashley

 

I am trying to work around the 1940s design of a single prop and rudder, I could fit a pair of wing engines with props but it would look to much like a MTB setup.

For the same reason I dont like the idea of forward facing props and fancy rudders as they are not in keeping with the design.

 

There is plenty of space to retro fit the jet system and whilst out of character it would not spoil the outward look of the model as even when under full speed it would be very hard to spot as the jet wash would be lost in the wake.

 

But I am still thinking.

 

Paul

[Paul TParticipant @pault84577]

Here is a photo of the 12v motor and primary gear…..the paint tin gives you an idea of size.

Still not 100% happy with fitting electric but needs must etc….

 

Paul

[Bob Abell 2Participant @bobabell2]

Paul

I think extra ballast may not be necessary, with such heavy a model……………….just let it ride high in the water?………………Then it won`t be 88lb then………more like 20lb?

 

What does it weigh at the moment?

 

Have you had a trial floatation test yet……………..would be worth doing at this stage?

 

Bob…………….just passing

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