Model Boat Mayhem - Forum

Please login or register.

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

Author Topic: single prop to twin prop  (Read 1205 times)

jaguarfold

  • Guest
single prop to twin prop
« on: July 13, 2010, 08:37:11 AM »

hi all new to site looking for advice im building a 1/24 scale crash boat my question is if i change it from a single prop and rudder to a twin prop configuration would i have to change the shape of the hull
Logged

malcolmfrary

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,568
  • Location: Blackpool, Lancs, UK
Re: single prop to twin prop
« Reply #1 on: July 13, 2010, 10:12:02 AM »

Unless there is something in the way of the props, no.  The areas that the proposed shafts pass through might need some strengthening.
Logged
"With the right tool, you can break anything" - Garfield

jaguarfold

  • Guest
Re: single prop to twin prop
« Reply #2 on: July 13, 2010, 10:33:18 AM »

thats good to know . i think twin props is more manoverable then single prop and rudder plus with the size of the boat the extra power will work well
Logged

Martin [Admin]

  • Administrator
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 19,101
  • Location: Peterborough, UK
    • Model Boat Mayhem
Re: single prop to twin prop
« Reply #3 on: July 13, 2010, 11:36:12 AM »


Also be careful not to over power the boat too much, ie. if the boat had a single 540/speed600 size motor,
 fitting 2 motors of the same size might be a bit much! A good tip I've learnt on here is start off by finding the
 scale size of the props you 'should' be using for that or a similar type boat and work out how much power / size
 of motor you will need to turn them.

If the single motor turned 40mm 3 blade high pitched props, then that's what the boat was designed for, fitting
a second one will produce a boat with twice as much power as it actually needs. Normally you wouldn't fit a 2nd
engine to a car just to make it faster or 'better' but you might think about 4 wheel drive (a 2nd motor prop in a boat).

Martin's Model Boat Power Motto:

1. Always try to over power your boat.
   ( Planning hulls always look better going a bit faster that scale speed.
    Over powering your boat also allows you to escape really wild wildlife!)

2. Never over, over power your boat!
    ( You can have too much of a good thing,
      see: http://www.modelboatmayhem.co.uk/forum/index.php?topic=24892.0
             http://www.modelboatmayhem.co.uk/forum/index.php?topic=24892.msg244821#msg244821  )

3. Always experiment.
    ( But know when enough is enough!)


Logged
"This is my firm opinion, but what do I know?!"    -   Mayhem FaceBook Group!

Perkasaman2

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 901
  • Model Boat Mayhem is Great!
  • Location: North East
Re: single prop to twin prop
« Reply #4 on: July 13, 2010, 01:07:06 PM »

Hi jag. The original twin Packard v12 placement/alignment given on the original plans ( see link below) can be transposed onto your  1:24 'scaled up' GG 'easy build' plan. However, your twin model motors can be mounted lower/closer to the keel and benefit from a more horizontal thrust alignment of the prop shafts. The boat's stability will also be substantially improved by the lowered engine placement.    Although the 'puter screen view' of the plans is small, by careful/accurate use of dividers measurements can be taken/scaled and transferred  to your 1:24 scaled build plan(s).

http://nobadlie.tripod.com/avrbp2.jpg

I agree with Martin's philosophy..... these Miami's were 40 knotters and high output/lightweight nimh batts on twin 600 ish motors should manage 'scale speed' (9.38 mph)   :}  
Logged
Pages: [1]   Go Up