Fun, Learning, Friendship and Mutual Respect
START  HERE


Unregistered
Go Back   HeliFreak > R/C Airplanes Info and Support > Airplane Related


Airplane Related R/C Airplanes Discussion


Reply
 
Thread Tools Display Modes
Old 09-10-2008, 10:02 PM   #1
rc.chris
Registered Users
 

Join Date: Jun 2007
Location: Georgia
Default prop

I am thinking of putting an older YS 91 4 stroke engine on an air boat, but the cage will only allow an eleven inch prop to swing. Does anyone have any suggestions on prop pitch for an 11" or maybe a 3 bladed prop?
rc.chris is offline        Reply With Quote
Old 11-19-2008, 06:41 AM   #2
Mr Rossi
Registered Users
 
Posts: 81
 

Join Date: Mar 2008
Location: Bournemouth, UK
Default

Easy, more pitch equals more speed less pull (5th gear in a car) less pitch equals less speed more push (1st gear) try an 11x6 as a start point. three blade props are hard to come by (in the UK anyway) and are less efficient.
Mr Rossi is offline        Reply With Quote
Old 11-19-2008, 12:00 PM   #3
invertmast
Registered Users
 
Posts: 3,333
 
My HF Map location
Join Date: Oct 2004
Location: North Port, FL
Default

Quote:
Originally Posted by Mr Rossi View Post
Easy, more pitch equals more speed less pull (5th gear in a car) less pitch equals less speed more push (1st gear) try an 11x6 as a start point. three blade props are hard to come by (in the UK anyway) and are less efficient.
Wow... thats somewhat right, but the prop sizing is WAAYYY off. an 11x6 is 1" smaller in diameter than what a 60 size 2 stroke would run (12x6 typically).

This being a 90 size, its going to need a larger prop or a smaller prop with ALOT of pitch. And the fact its a 4stroke means it can run an even larger prop than a 90 2 stroke.

Meaning you'd need between a 13x6 to 15x8, since this is a 4-stroke you should really use the larger 15x8 prop. So if you have to have a 11" prop, that means you should be runnin an 11x12. which APC make an11x7,11x8 11x9,11x10,11x11 and 11x12

Now that u have a recommended prop, its best to purchase one and see where it falls in your RPM range recommendation for your particular engine. I believe my YS 1.70DZ which spins a 15.5x12.5 4-blade prop spins this at a max 7800 rpm for comparison.
__________________
Comparf Eurosport
1/7 F-14D
Rave 450, scorpion -10, DS285MG, 3500G, Spartan, 4s 2200 outrage, 6100e, 350mm radix
lookin for another Vibe 50
invertmast is offline        Reply With Quote
Reply




Unregistered
Go Back   HeliFreak > R/C Airplanes Info and Support > Airplane Related


Airplane Related R/C Airplanes Discussion

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


Copyright © 2004-2015 by RCGroups.com, LLC except where otherwise indicated. The HeliFreak.com logo is a trademark of RCGroups.com, LLC.