Barrel Back….

[Paul TParticipant @pault84577]

Morning Ashley

 

The barrel back on my boat is a “typical” of the period as the design did vary…..some transom’s were rounder than others…..but the designers all tried to atchieve a flowing line from the sharp bow through the wider cockpit area to the rounded stern.

The changing design reflected the art deco style of the period and required a lot of skill to build, if you compare the barrel back style to the boats that were built after WW2 you can see the change in design and style from complex and skilled to plain and mass produced.

 

I now have another problem

 

I can’t get insurance on the model whilst it has a petrol engine!

The insurers will cover the boat for storage and display but not for sailing under IC power as it is to big and heavy……they say that if radio control failed the model would become a significant risk to other lake users…..it would be cheaper to insure a full size speedboat.

 

I am having a bad week and its only Tuesday.

 

Paul

[ashley needhamParticipant @ashleyneedham69188]

Paul, At least you have the room for a nice large car battery and a big ELECTRIC motor inside the hull…….Ashley.

[Paul TParticipant @pault84577]

Hi Ashley

 

Yes plenty of room but not enough vroom it looks like I am doomed to have plodding donkey rather than a sleek greyhound.

 

Stll its not worth crying over spilt milk.

 

Back to the drawing board to have a play with gearboxes and high amp gel batteries.

 

Paul

[Bob Abell 2Participant @bobabell2]

Hello Paul

 

We went to Etherow today and our member Barrie had his speedyboat with him.

So I took this picture to give you some inspiration for your Barrelback

 

Ir runs on two brushless motors and performs well, no pictures of it sailing, I had the wrong camera with me

 

Bob

[Bob Abell 2Participant @bobabell2]

Here`s the plan view…….has working lights and sound effects

[ashley needhamParticipant @ashleyneedham69188]

Wow wow wow. My sort of boat !  I cant wait to see Paul’s,  Mahogany and Pear wood planking on deck with Ebony stringing ,sumptuous leather upholstery and….er, 2x brushless motors??  Ah well,,,,cant have it all.   Ashley

[Paul TParticipant @pault84577]

Thanks Bob

 

Its a very nice model of a Riva you friend is a lucky man having such a model to play with.

 

As soon as I can I will post some more photos of the progress that I made before my little problem.

 

Thanks again Bob

 

I’m off back to bed now before Jane catches me on the computer.

 

Paul

[PierreParticipant @pierre]

Hi Paul

Your model looks great! I was just wondering how you control your motor, speedwise?

Also the rudder servo -how big a servo are you going to need to turn a presumably fairly large rudder?

I’m enjoying your pics – reminds me of building a mirror dinghy years ago!

Cheers – Pierre

[Paul TParticipant @pault84577]

Hi Pierre

 

The 2 stroke motor has a simple cable to control the carb, just like a car, except that the cable is connected to a standard servo. as long as the tick over is set high enough to prevent stall the set up works very well.

 

You are right about the rudder being large and hard to move, I am going to play with heavy duty servos and if that won’t work then I shall use a geared motor through a speed controller.

 

It is a lot like dinghy building and just as much fun to do.

 

Paul

[Bob Abell 2Participant @bobabell2]

Er!……………………..We thought you`d put the big boat project to one side for the time being!

 

Dr Bob

[David MeierParticipant @davidmeier28154]

Hi Paul.

I have a mind to build a fast submerged drive model one of these days, using a 26cc line trimmer motor. I was wondering what size is the motor you are using in your boat and what size prop will you use? I have no feel for the prop size needed and don’t want to be in the situation where I haven’t got enough clearance between prop shaft and hull, to fit the right size prop.

 

David.

[Paul TParticipant @pault84577]

Hello Dr Bob

 

Work on the model has been suspended for the time being (I couldn’t pick it up anyway)

But I can still do little bits on it like the seats and cockpit details.

 

Hi David

 

The engine that I had intended to use is a 35cc unit c/w clutch but I have had a great deal of trouble in being able to find a lake where I could sail as most waters have banned IC engines. So I am reduced to finding an electrical substitute.

The intended prop is a 3 bladed, 50mm dia brass version with a 6mm thread. I have opted for this prop as it looks more like the props of the 1930s – 1940s, for better performance I could fit a modern 2 blade version

 

Paul

[ashley needhamParticipant @ashleyneedham69188]

Paul. This 50mm prop is intended for the petrol version, or the enforced electric one?? My 800 motors spin 50mm 2-blade racy props ok,     50mm sounds very small to me for such a hulking petrol engine…..from the viewpoint that I know nothing about petrol/diesel motors.

Mind you, I was at the Isle Of Wight Classic boat museum in Newport (a very nice small museum well worth a visit) and there was a …..memory fails me here…”miss new england” ..or some such 90mph speedboat thingy all polished wood and brass….and that had a monstrous engine in the rear of the boat, all carbs and pipes, but It also had the most ridiculously small propeller. It was fitted with the original prop, but if I didnt know, I would have vouched the professional opinion that it was way too small. Ashley

[David MeierParticipant @davidmeier28154]

Thanks guys. Yes I would be interested to know if the 50mm prop was intended for the petrol engine or the electric version Paul.

David.

[Paul TParticipant @pault84577]

Hello Chaps

 

The 50mm is intended to keep the model within scale, I could fit a 100mm prop to this engine but it would look daft.

 

It would be a fast bugger though.

 

Paul

[ashley needhamParticipant @ashleyneedham69188]

fast does if for me, after all….who is looking at the prop when its in the water?? Ashley

[Paul TParticipant @pault84577]

Hi Ashley 

Fast is one thing but this boat with a 100mm racing prop would be suicidal, even though it’s a heavy model the design programme gives a potential top speed in excess of 38mph.

This might not sound too rapid in relation to road speeds but on a lake it is very fast.

If you fancy having a go at something like this I will gladly email the drawings of the barrel back down to you.

Paul

[David MeierParticipant @davidmeier28154]

Hi Paul and Ashley. To get maximum speed using the 50mm prop, would gearing it up say 2:1 work do you think? It would be a shame to have all that power and not harness it.

David.

[Paul TParticipant @pault84577]

Hi David

 

Gearing would produce more speed or I could fit two props as the engine has plenty of grunt but speed isn’t the problem.

Keeping control of a large, high speed and heavy model requires quick reflexes and nerves of steel (I have neither)

I would also need a large stretch of open water where I could fully “open the taps”

 

Paul

[David MeierParticipant @davidmeier28154]

Thanks Paul. That has given me an idea of how to approach a future fast boat.

David.

[Paul TParticipant @pault84577]

More photos

 

 

Mahogany planked over the ply base

 

Spot the mistake

 

Didn’t need to much filler

 

 

Jane allowed me to put one coat of varnish on to seal the wood.

Paul

 

 

 

 

 

 

 

 

 

 

[Bob Abell 2Participant @bobabell2]

Hey Paul!!!!!!!!!!!!!!!!

 

That`s looking great!!!!…………………and I`m pleased to see that you are well enough to make progress again……………….but don`t overdo it!

 

You`re a fast worker when you get down to it!

 

What about the power plant?…………….big brushless motor(s)???????

 

And running on 24 volts?

 

Bob

[ashley needhamParticipant @ashleyneedham69188]

wow wow wow. looks fantastic.How big do brushless get? hows about a geared pair of 850s for some serious TORQUE   Ashley

NB You really need a driver, an open top speedboat with no driver looks silly (in my opinion)

[Paul TParticipant @pault84577]

Hi Bob

 

Thanks for the comments

 

Whilst I feel 100% better than I did I am taking it very easy Jane let me put a sealing coat of varnish on the mahogany just to protect it from damp in the shed.

 

Still not sure about the power plant but I can’t afford big brushless motors so it looks like a starter motor or something of that ilk.

 

Paul

[David MeierParticipant @davidmeier28154]

Gee that is looking fantastic Paul. Doesn’t it come up well with the varnish on. I think you must have been working on it under the bed covers while you were in hospital to make that much progress. No wonder you haven’t had time to take a photo of your workshop. (Couldn’t resist another dig).

David.

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