Model Boat Mayhem - Forum

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: Flexi/cable propshafts...a mystery?  (Read 3011 times)

Dave Bardick

  • Shipmate
  • *
  • Offline Offline
  • Posts: 20
  • Model Boat Mayhem is Great!
  • Location: UK
Flexi/cable propshafts...a mystery?
« on: April 10, 2014, 06:53:28 PM »

As a fun RC boat enjoyer with a few years of bodging and bashing behind me I'd like to use up some spare components on a silly build and need some advice. Last year I modified a Tear Into cheapo jet boat replacing motor, ESC and battery with a brushless setup. Very popular, easy and fun too.


I'd like to use an old cheapo 'Stealth' twin-propped hull commonly found on ebay/amazon for 40-50 (super-lightweight with quite a nice hull) and adapt it to take a single 2858 brushless motor with a surface prop using a flexi shaft. I know nothing about this type of propulsion but understand why a flexi shaft is required.


Are there any previous posts about the matter I can read before wasting other people's time?


What do I need? An output unit (?stinger) and a rudder but how do I connect the components? Graupner seem to do a flexi coupling. Could I then connect to the ?stinger using a standard propshaft (stainless shaft and brass stuffing tube) or should the whole drive length be cable/flexi?


How do I optimise the ?stinger unit position during the final build assuming the set up is intended to be of the surface-prop variety. I assume again that this is largely down to setting the boat in a bath to measure displacement etc?


I was filming my friends lads twin-propped toy boat from my MFA Piranha the other day and although unimpressed by the boats powerplant(s), twin 380 motors, I couldn't believe how light the boat was. As a cheap toy the thing represented great value for money and outlasted my Piranha after I hit a submerged something-or-other flat out and mutilated my rudder.


I have so many unused components I'd love to throw them into a cheap boat but simply can't get my head around the flexi/cable propshaft thing.


Cheers in anticipation of advice or a link or two for half-wits like myself!


Dave
Logged

w3bby

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 773
  • Location: Helsingborg, Sweden
Re: Flexi/cable propshafts...a mystery?
« Reply #1 on: April 11, 2014, 12:33:01 PM »

Surface drive components here. Think it is self explanatory... Otherwise this thread has some pics of install..

Stinger/ strut has adjustment so it is down to trimming the boat after you have run it.

Dave Bardick

  • Shipmate
  • *
  • Offline Offline
  • Posts: 20
  • Model Boat Mayhem is Great!
  • Location: UK
Re: Flexi/cable propshafts...a mystery?
« Reply #2 on: April 11, 2014, 02:39:10 PM »

Ian,


Thank you for reading and helping with my newness to flexi shafts/stingers! I'd been trawling some of the popular RC boating websites looking at components I couldn't quite understand. None seemed to stock the complete list of components required. Your first link is superb and I can see that PMB supply what I'm after. The Omra Makara photos and text shed a lot of light on the subject too. I'll read the whole thread later and give PMB a call next week.


Brilliant,


Thanks again!


Dave
Logged

mattf1000

  • Shipmate
  • *
  • Offline Offline
  • Posts: 15
  • Model Boat Mayhem is Great!
  • Location: North Wales
Re: Flexi/cable propshafts...a mystery?
« Reply #3 on: December 10, 2014, 09:03:30 PM »

I've got a piranha in the garage running a surface drive unit from Prestwich models it completely  transformed the boat even on old nicads  and old 18 turn brushed motor. I'll dig out some pictures when I get a minute
Logged

Dave Bardick

  • Shipmate
  • *
  • Offline Offline
  • Posts: 20
  • Model Boat Mayhem is Great!
  • Location: UK
Re: Flexi/cable propshafts...a mystery?
« Reply #4 on: December 11, 2014, 05:49:22 PM »

Matt,


Superb. I was thinking of converting my Piranha to a surface drive with a small brushless setup.


I'd love to see those photos. I'd love to know what hardware you used.


If you're happy with the brushed surface drive I could save a little money and use the 600BB motor/esc and just fit the hardware/flexi drive.


Had a great summer with the doublehorse toy boat conversion.


The flexi-drive turned out to be a lot easier to fit than I thought and the boat appears to be perfectly powered with a 15 brushless motor.


You can see the doublehorse in action here https://www.youtube.com/watch?v=EynXN7pouTg


Skip to the 2:35 mark.


Some of it was filmed from the green Piranha.


Cheers,


Dave
Logged

mattf1000

  • Shipmate
  • *
  • Offline Offline
  • Posts: 15
  • Model Boat Mayhem is Great!
  • Location: North Wales
Re: Flexi/cable propshafts...a mystery?
« Reply #5 on: December 11, 2014, 06:11:24 PM »


it's a different setup now and unfinished as I was converting it to ic. But the principles  the same. It requires the stern to be beefed up a bit on this set up but i havent got round to it yet. I had some video on my phone but cant find it
Logged

mattf1000

  • Shipmate
  • *
  • Offline Offline
  • Posts: 15
  • Model Boat Mayhem is Great!
  • Location: North Wales
Re: Flexi/cable propshafts...a mystery?
« Reply #6 on: December 13, 2014, 02:37:39 PM »

MFA PIRHANA ON A SURFACE DRIVE SETUP: http://youtu.be/Ts2JTayTXDM
found an old vid. I think it went quite well
Logged

Dave Bardick

  • Shipmate
  • *
  • Offline Offline
  • Posts: 20
  • Model Boat Mayhem is Great!
  • Location: UK
Re: Flexi/cable propshafts...a mystery?
« Reply #7 on: December 14, 2014, 02:05:04 PM »

Excellent!


It goes really well on the nicad/modified motor combo and looks well-balanced.


That's my late-winter project sorted!


The Doublehorse conversion allowed the flex-drive tube to emerge from the transom whereas your drive looks like a stinger that emerges from the underside of the hull. The Piranha transom seems too shallow for any alternative.


I don't suppose you have a photo of the underside of the hull? I'd love to see how you fitted the flex-drive tube/stinger.


Cheers,


Dave
Logged

Dave Bardick

  • Shipmate
  • *
  • Offline Offline
  • Posts: 20
  • Model Boat Mayhem is Great!
  • Location: UK
Re: Flexi/cable propshafts...a mystery?
« Reply #8 on: December 14, 2014, 02:21:09 PM »

Ha!
Forget my last message.


I'm blind!


I can see the upright strut leading upwards to the rudder mount. There's no stinger drive!


Gotcha!


I couldn't see it at first and thought you'd mounted a stinger on the underside of the boat.


Cheers for the photo and video,


Dave
Logged
Pages: [1]   Go Up