Bertram31.com General Bulletin Board

Re: Help Mike!

Posted By: capy
Date: Tuesday, 16 August 2005, at 8:51 p.m.

In Response To: Re: Help Mike! (thuddd)

Timmy,

There is no way you have 1.5:1 gears, cause with 24x24 props you would not make 2000 rpms never mind 2400.

DD recommends no load speed (transmissions in neutral) of 2970 rpm. Max full load speed 2800, minimum full load speed 2500, but with accelerated wear of rings and valves due to excessive exhaust gas temps. You should shoot for 2750 or 2800 full load speed.

That said, I will remind you that I make 2800 rpm full load speed with 3 blade 21x19 with heavy cup to reduce slip. I have 1.5:1 gear reduction. Some years ago I tried 3 blade 21x21 no cup props and only made 2550 full load speed.

I suggest you try these props as I only keep them as spares and never use them. They are repitched from 19 inch pitch and reconditioned and not the best but, are free to you.

You just need to have them bored to 1.5" dia shaft taper from the current 1.375"

If these props let you overspeed to say 2850, then I would be comfortable recomending something like a 22x20 four blade with light cup which will probably let you get to 2700 or so.........

good luck.

Paul

Messages In This Thread

prop questions
thudddd -- Monday, 15 August 2005, at 4:17 p.m.

Re: prop questions
Walter Kaprielian -- Monday, 15 August 2005, at 5:20 p.m.

Help Mike!
Bruce -- Monday, 15 August 2005, at 6:21 p.m.

Re: Help Mike!
mike ohlstein -- Monday, 15 August 2005, at 7:10 p.m.

Re: Help Mike!
Capt. Dick Dean -- Monday, 15 August 2005, at 8:45 p.m.

Re: Help Mike!
thudddd -- Tuesday, 16 August 2005, at 8:42 a.m.

Re: Help Mike!
andre fourrier-Louisiana -- Tuesday, 16 August 2005, at 9:22 a.m.

Re: Help Mike!
thuddd -- Tuesday, 16 August 2005, at 9:56 a.m.

Re: Help Mike!
capy -- Tuesday, 16 August 2005, at 8:51 p.m.

Re: prop questions
Gary Gibson -- Tuesday, 16 August 2005, at 4:21 p.m.

Re: prop questions
Paul J -- Tuesday, 16 August 2005, at 5:38 p.m.

Re: prop questions
thuddd -- Wednesday, 17 August 2005, at 8:57 a.m.

Re: prop questions
Paul J -- Wednesday, 17 August 2005, at 9:47 a.m.

Re: prop questions
capy -- Wednesday, 17 August 2005, at 11:47 a.m.

Re: prop questions
thuddd -- Wednesday, 17 August 2005, at 4:16 p.m.

Re: prop questions
Gary Gibson -- Wednesday, 17 August 2005, at 5:49 p.m.

Re: prop questions
thuddd -- Thursday, 18 August 2005, at 9:54 a.m.

Re: prop questions
Carl -- Thursday, 18 August 2005, at 12:30 p.m.