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[Bill D203]

I am not sure if this has been covered somewhere Else on mayhem but here goes.
I am looking into building a Model by design Arun life boat. I was looking at one at Wiki park this year. The Model boat will I'm sure take a 23cc petrol engine as it's power plant. However i have picked up that it was a twin shaft and prop boat. Now has anyone fitted a single shaft to this type of boat? If so did they have any problems!!
If the boat will only run as a two shaft /prop set up I'm going to work out how to do it with gears/belts or even the petrol engine driving a dynamo. Clearly I could do with some advise before i by spend out and buy the boat.

[DickyD]

Wont this limit you to where you can use it, being i/c I mean ?

[johno 52-11]

Hi Bill

I run an Arun the same size as the Model by Design one although mine is scratch built. To give you some idea of power I run my boat on 2 Graupner speed 900's on 12 volts driving 2 60mm 4 bladed props and this gives me scale speed. There are a couple of people who are running Arun's with brushless motors and achieving  speeds well over scale speed and I'm sure they will tell you what they are using.

To the question of using a single prop, I have just had a look at my Arun and the keel dos finish before the back of the boat so you may be able to fit a shaft in there. The problem I would see with this is that it will put the prop even deeper in the water than the two in there designed position. Another thing to also consider is would you have enough room behind it for a rudder.

The other thing to consider if you did use a single prop is the control of the boat. the hull is a round chine hull and with a single prop at higher speeds would you get any paddle effect that would make it difficult to steer?

John

[6705russell]

Maybe it will also be a little to fast for a scale boat and not look the part, also with one prop i should imagine for such a large hull there will be a stability problem?

Russ

[Bill D203]

Wont this limit you to where you can use it, being i/c I mean ?

Good thinking, however I can run it here at Stevenage and where I run my offshore boats during the lunch breaks.
At this stage i want to find out if it will run on a single shaft/prop set up. So even if you have run a smaller type Arun on a single lecky set up i like to hear how it runs
I think it will be fine but I want to double check
I have a Donner engine lined up. It is in a RTR bat boat at the mo. Now I have taken that boat out today and i can get the revs down real low and with a smaller prop I'm sure i can get it fairly slow. The engine dose have a throttle which i will need to hold back. I don't want to race it just have some fun. Don't forget I'm the man who put a petrol engine in a Springer tug and that goes real slow.

[Bill D203]

just a very quick note. Ordered thr MBD Arun  from them at Weymouth. I am going ahead with the petrol engine setup. I had a good look at Lifeboat Pauls Arun and got louds of help from him. Thanks Paul. I will post the build here when i get going. Cheers for now

[Bill D203]

I'm counting down the days till i get my Arun to start on now. Been down in South Devon and been asking loads of stuff at the lifeboat stations that we have been too.

[Bill D203]

Still Waiting to get the boat here. Oh well maybe it will get here VERY soon.

[Bill D203]

Well the boat made it here to Stevenage earlier this week. I started work on her today. I made the rear handrails. I was made up with the result as I have Never silver soldered before.

[Bill D203]

Here'safew more pics of the build. My mate is going to make me a gearbox so work on the drive has not started. Still lots to do !

[Bill D203]

A bit more done & tested out the C/G  today down our club. it is all going in the right direction. The plan for the gearbox is underway, the engine has been mounted in the boat so we can get an idea of what shape to make the gearbox. It should be ready for a run out just as the lake freezes over but ha ho!
Thanks Andy for taking the photo on his phone.

[Shipmate60]

Bill,
Is this any use?

http://cgi.ebay.co.uk/Gearbox-1-2out-large-glow-nitro-motors-Zenoah-/130426125113?pt=UK_ToysGames_RadioControlled_JN#ht_500wt_1154

Bob

[Bill D203]

Bill,
Is this any use?

http://cgi.ebay.co.uk/Gearbox-1-2out-large-glow-nitro-motors-Zenoah-/130426125113?pt=UK_ToysGames_RadioControlled_JN#ht_500wt_1154

Bob

Hi Bob
I did look at the gearbox however the shafts are not as wide as i need them. I got the gears last week and my mate will be back on the case next week when he gets back from his hols. Heres a few more pics

[Dan.Lord]

Smashing work on the hand rails Bill, looks like it's going to be a really nice boat when she's finished. Keep up the good work Dan.

[Bill D203]

Smashing work on the hand rails Bill, looks like it's going to be a really nice boat when she's finished. Keep up the good work Dan.

Thanks Dan.
I have done lots of normal soldering as I am a electrical engineer but Never Silver solder before. I was very happy the way the railings turned out.
With the engine, lecy starter motor, gearbox etc i have got to work out what size fuel tank and radio box i can get in the boat. 
I am going to the Deans marine open day on Saturday as i need to get a bow truster, props and shaft shorted out next. Hopfully Ron will be able to fix me up?

[johno 52-11]

Hi Bill

That gearbox looks good. I don't know if you have taken this into account but my Arun when running both motors at full speed has quite a large turning circle of about 25 feet. To get a tighter turn at full speed I slow or stop the motor on the inside of the turn. With your gearbox you are not going to be able to do that unless you fit some sort of clutch to each shaft or oversize rudders might help. Just a thought..

John

[Bill D203]

Hi Bill

That gearbox looks good. I don't know if you have taken this into account but my Arun when running both motors at full speed has quite a large turning circle of about 25 feet. To get a tighter turn at full speed I slow or stop the motor on the inside of the turn. With your gearbox you are not going to be able to do that unless you fit some sort of clutch to each shaft or oversize rudders might help. Just a thought..

John

Cheers for the info John. At the moment i am keeping the box as both drive all the time. lets hope it will be Ok If not a clutch system may have to be fitted.  I am going to a big Jumbo servo on the rudders so there will be a fair bit of power to pull/push the rudders. Fingers crossed.

[HS93 (RIP)]

have you seen this ? there may be some info that may help you even if its just the engine drawrings

peter

http://www.pt-boat.com/zenoah/Zenoah.html

[Bill D203]

have you seen this ? there may be some info that may help you even if its just the engine drawrings

peter

http://www.pt-boat.com/zenoah/Zenoah.html

Cheers for the info Peter.
Work on the gearbox is underway. The MHZ gearbox is not as wide as i want it hence having to go down the line of making one. 

[Bill D203]

Had the top primer painted today. Now I can see you the bits and bobs which need filling and sanding. Found out yesterday the paint can be mixed to the BS numbers, It comes in handy working on spraybooths for a living.

[Bill D203]

Help
I am trying to set up the wiper movement. I have had a go at useing a boden cable but the result was not that good. How is it done? If you can help , a pic or 2 may help me out loads.

[gribeauval]

I used a small servo modified for constant rotation pulling a thin fishing line with a section of rubber at one end through guide tubes that will be hidden by the wiper boxes later. The wipers will be clipped to this line.

This short clip explains things better, the tape is to mark where the wipers will fit to avoid hitting the sides of the frames.

http://www.youtube.com/watch?v=A46tIotO-7Y

[Bill D203]

I used a small servo modified for constant rotation pulling a thin fishing line with a section of rubber at one end through guide tubes that will be hidden by the wiper boxes later. The wipers will be clipped to this line.

This short clip explains things better, the tape is to mark where the wipers will fit to avoid hitting the sides of the frames.

http://www.youtube.com/watch?v=A46tIotO-7Y

THANK YOU. just what I have been looking for. Now I have used a boden cable with a moded servo to push and pull it. i have to fit a light spring to get the return right. Your way dose push & pull with No spring. Brill !

[gribeauval]

THANK YOU. just what I have been looking for. Now I have used a boden cable with a moded servo to push and pull it. i have to fit a light spring to get the return right. Your way dose push & pull with No spring. Brill !

The trick is to get the tension on the elastic section just right. Too slack and it won't return, to tight and the servo can stall !! 

Good luck,   


Mike

[Bill D203]

Been to see my mate who is making my gearbox today. All the design work is now done and the real work is now underway. I still have loads to do but it should be ready for next years session. 
I got the wipers to work and have been working on the Y boat jib. I will try and post some more pics at the weekend. Off to the spare room to do a bit more now.
Next job is to make the control relay/ fuse PCB. Thanks to Action electronics (Dave) for finding me the relays I need to build it with.