Prop Choice
 

Greetings All,

I am a transplant to the NW part of New Mexico, and the field I fly at is at about 6000 feet... back in New York the field was maybe 500 feet.

I have noticed that I dont get the climb performance here in NM I got in NY, so I think I need to switch props.. so do anyone who flys at 6000+ have any advice or know of a resource on the net I might find this info?

my plane is a Great Planes Big Stik 40 (kit built) weighing 6.3 lbs with a OS 70 4 stroke and a Master Airscrew 12-8 4 stroke prop (K series)

I would rather stick to MA props as they are not as brittle as APC.. and I dont have much ground clearance (1/2 inch) to play with, so a 13 inch prop is out..

thanks for the help & keep your glow plug out of the dirt

Charlie Fischer

Prop Choice
 

At higher altitudes you can use higher nitro - when I moved up here to Colorado, I moved up 5% in my nitro to help get back a little bit of the power in my 46FX. I run 30% in all of my saitos. You have lost about 20% of your power at 6000', just like me...

Also, I lost about 800 RPM with the same prop when I moved here, and that was with using 5% higher nitro. So for you, I would say try a lower pitch prop, like a 12X7, if the RPM doesn't go too high, or try a 12x6 three blade prop. (I have used 3-blade props alot, with great success. I don't think they are as inefficient as everyone states, when you compare the same brands.)

Hope this helps - NJD

Prop Choice
 

Used a Master Airscrew ONCE!!! Never again! It was like something sucked the life out of my engine. Been running APCs ever since. Brittle or not.

Prop Choice
 

A prop will not make much difference.

But a new 91 will. It doesn't weigh anymore than the 70.

The nitro helps too.

Enjoy,

Jim