Takeoff rpm

[Bandit 286]

Wanted to try my Bandit again to see how it started. It fired on the first pull after 3 pumps of the primer. Dispite the 20-25 mph gusts I decided to fly Anyway. While taxing across the road to the field I remembered that I wanted to repitch my prop to get more than 5900-6000 rpms during takeoff. Shut it down and took some pitch out. Started it back up and started my takeoff into a 20 mph wind.  The Tiny Tach read about 6400 rpms. Holy shit I didnt ever think I was going to get off the snow. I hit the go no go spot and finally broke loose of the snow. Good thing the trees were coming up. Hit the turbulance coming off the trees and really rocked me. My Bandit felt like it was spinning its wheels. It would not climb worth a crap. Flew away from the treelines and got over the fields where it was a little smother. I was getting 6500 rpms flat out, but I was only indicating about 70 mph. I was flying around like a dog dragging his ass across the lawn. I need at least 76 mph indicated to feel like my airplane is up on step. The hell with high rpm takeoffs. My Bandit gets off the best at around 5900-6000 rpms on takeoff. This setting also gives me the best cruise. It is a pretty fine line between the best takeoff rpm and cruise. 

 

[tcj 150]

My 503 seems to like 6250 RPM static.  On take off I haven't ever looked at the instruments until after it lifts off.  Then I glance down to check RPM and Egts before starting to climb.  The RPMs will be 6200ish.  If I keep nose down and let the speed and RPMs build they will hit 6700.  Then best climb is to hold RPMs at 6000.

In cruise it seems to like 6000 too...but it takes much less throttle.  At that RPM airspeed was 75 mph before I installed lift strut fairing and 85 mph now with fairing.

The prop is a 72 inch two blade Warp square tip and gear box is 3:1 ratio.  When I bought the prop I called Warp and asked what prop would give shortest take off and best climb with this combination.  I didn't care much about cruise speed.  If i want to go fast I ride my 670 Ski Doo.

 

 

Edited 29 Jan 2016 by tcj

[TJay 1041]

On my challenger I set static to 6250 also, gives me 5900 on climb and I cruise at 5400 to 5600 any thing more on them little engines and it just drinks the fuel. I also tried to set static at 6500 once absolutely terrible climb and cruise was barley over 55 mph.