Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Pleasure boats, Sports, Race, Power and Leisure Boats: => Topic started by: Jim-H on August 22, 2016, 11:38:38 pm

Title: Prop Size for a Huntsman
Post by: Jim-H on August 22, 2016, 11:38:38 pm
Forgive me if this has already been covered but I can't find it if it has.....
I'm revitalising an old Huntsman type hull with twin brushless,  the hull is 790mm long on the waterline,250mm beam and will displace 4.8 kg when down to it's marks.  It is deep vee with a 50o included angle.  The motors are Turnigy 790kv brushless rated at 720watt each and I'll be using 4 cell (14.7v) lipo batteries.
Has anyone any suggestions as to prop size and pitch ? Any advice would be welcome.
Jim
Title: Re: Prop Size for a Huntsman
Post by: canabus on August 23, 2016, 09:14:40 am
Hi Jim
40mm x 1.4 pitch I use on 35mm motors(3639-750, 3639-1100,D3548/4-1100,3648-850 and 3648-1450kv.
Hobbyking have packs(5 off) for left and right ones cheap also the same in 42mm.
I am using the D3548/4-1100 kv with a 40mm x 1.4 pitch in me Sea Commander on a 3S 5800mah.
It is not slow and will give a few speedboats a run for their money!!!!
Title: Re: Prop Size for a Huntsman
Post by: Jim-H on August 23, 2016, 10:27:27 am
Thanks Canabus, sounds like a good place to start.  I'm trying to get the propshafts as parallel as possible to the hull to get max efficiency.
Jim
Title: Re: Prop Size for a Huntsman
Post by: canabus on August 23, 2016, 11:19:25 am
Hi Jim
Good plan with the prop shafts.
Are you using solid couplings or uni's???
The solid one's are quieter!!
On model boats forum I posted a motor alignment tool which in a disc with a long piece of shaft(what size you make the disc).
Fix the disc to the motor mount and to the shaft(with the outer of the driveline).
I place a piece of 2mm plywood under the disc and added a 50mm prop to the other end, then taped the prop to the hull.
This gave me 5-10 mm clearance for my props.
After setting the mount and drive line, I removed the disc and long shaft.
Installed my setup and the prop shaft went into the coupling spot on.
I will find the link and post.
 
Title: Re: Prop Size for a Huntsman
Post by: canabus on August 23, 2016, 11:22:21 am
Hi Jim

One motor tool link http://www.modelboats.co.uk/forums/postings.asp?th=117243