Model Boat Mayhem - Forum

Please login or register.

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

Author Topic: Motor advice needed  (Read 2116 times)

RickF

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 918
  • Black, white and buff - not grey!
  • Location: Norfolk UK
Motor advice needed
« on: June 23, 2008, 08:11:12 PM »

Guys,

Can anyone recommend the best motor/mixer set-up for the following model?

1:48 scale gunboat, 60 inch long by 7 inch max beam with smooth, round-chine hull. Twin three-bladed props, scale size 54mm but I'll probably use 50mm. Six volt power supply. Maximum speed of prototype 16 knots (19 knots forced draught).

Any advice appreciated

Rick
Logged

DickyD

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 9,497
  • www.srcmbc.org.uk
  • Location: Southampton UK
    • SRCMBC
Re: Motor advice needed
« Reply #1 on: June 23, 2008, 08:15:46 PM »

PM shipmate60 he's your man. O0
Logged
Richard Solent Radio Controlled Model Boat Club http://www.srcmbc.org.uk

Subculture

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,905
  • Location: North London
    • Dive-in to Model submarines
Re: Motor advice needed
« Reply #2 on: June 23, 2008, 08:43:12 PM »

12 volt system would give you a better choice of motors.

Two Graupner 720BB direct drive should sort you out. You don't mention the pitch of the props, but the 720's should be able to push most props round of that size.

Andy

Shipmate60

  • Global Moderator
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,263
  • You bark - I will bite!!!
  • Location: Fareham
Re: Motor advice needed
« Reply #3 on: June 23, 2008, 10:28:28 PM »

700 BB Turbos will be fine, but not on 6 volts.
I dont know of anything that will shove a boat that big along at a decent speed on 6 volts.
If you go 12 volts you have the choice of using BB turbos or brushless or car blower motors on huge props.
The BB turbos dont like lead acid gel cells so a good battery pack is essential, one that can deliver sustained high current.

Bob
Logged
Officially a GOG.

pomybill

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 32
Re: Motor advice needed
« Reply #4 on: June 23, 2008, 11:37:19 PM »

Hi Rick,
Have a look at the "Huntsman Power" thread on this site. Lots of good advice and plenty of ideas.
Pomybill.
Logged

FullLeatherJacket

  • Guest
Re: Motor advice needed
« Reply #5 on: June 23, 2008, 11:44:46 PM »

Rick
Just to confirm IMHO what my esteemed colleagues have already said, 6v for a model this size is pants. BTW Is this a planing hull e.g. Perkasa or an older semi-displacement type?
FLJ
Logged

RickF

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 918
  • Black, white and buff - not grey!
  • Location: Norfolk UK
Re: Motor advice needed
« Reply #6 on: June 24, 2008, 09:42:39 AM »

Thanks for the advice, guys.

FLJ asks if this is a planing hull or a semi-displacement type. As you can see from the picture below, neither description really fits the bill!



HMS Spanker (yes - that really is her name) Sharpshooter-class torpedo gunboat, 1888.

Logged

Shipmate60

  • Global Moderator
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,263
  • You bark - I will bite!!!
  • Location: Fareham
Re: Motor advice needed
« Reply #7 on: June 24, 2008, 09:57:56 AM »

For those props I would go for  3:1 geared 550's on 6 volts then.

Bob
Logged
Officially a GOG.

HS93 (RIP)

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,949
  • I cannot spell , tough
  • Location: Rainhill UK
Re: Motor advice needed
« Reply #8 on: June 24, 2008, 10:06:17 AM »

And use belt drive , look at the MFA units you can change the ratio without a lot of fuss.

Hs93
Logged

RickF

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 918
  • Black, white and buff - not grey!
  • Location: Norfolk UK
Re: Motor advice needed
« Reply #9 on: June 24, 2008, 11:37:38 AM »

Thanks again. MFA = Model Flight Accessories?. Would you recommend a mixer ( she has a single balanced rudder) or controlling two motors from one ESC?

Rick
Logged

FullLeatherJacket

  • Guest
Re: Motor advice needed
« Reply #10 on: June 24, 2008, 03:48:03 PM »

Here's some stuff for you to mull over; suit yourself as to what you do, but I never recommend two motors to one ESC unless you're talking about very small models e.g. plastic magic.

http://www.action-electronics.co.uk/pdfs/Twins%20Ver2.pdf

BTW that hull is quite definitely NOT a planing type!
FLJ

Logged

RickF

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 918
  • Black, white and buff - not grey!
  • Location: Norfolk UK
Re: Motor advice needed
« Reply #11 on: June 24, 2008, 07:13:57 PM »

Thanks FLJ, interesting stuff. No she'd not plane, not even flat out under forced draught!

Rick
Logged
Pages: [1]   Go Up