could anyone tell me if a 20x10 prop would be close to a 22x8 as i need ground clearence. the 22x8 turns 6300 rpm on my 50cc gas engine

Reasonably close. It depends on the brand but is worth a try.

I tried this last fall. I went from a Xoar 22x8 to a Xoar 20x10. I gained about 500~600 rpm.

I think a 3W brand 20x10 prop may load an Engine a bit more than some brands in the same size ..

Jim

Usually, within the same brand, 1" dia. equals 2" pitch for the same load on the engine.

Martin

Less thrust, more speed. Longer to get off the runway but faster in the air, with a little less vertical pull.

Also faster landing speeds........... Capt,n

How about a three blade prop? Couldn't tell you what size though.

V/r,

Richard

Harley, How much ground clearance do you have with the 22x8? I will have the same problem on mine, 3" clearance taxing and 1.5" when level. I was planning to add some supports to the landing gear (crossed spring and cable) so they would not spread much.

If I cannot live with the 22" prop, I don't want to go to a 10 pitch, so I was thinking about a Xoar Laminated 3 Blade 20x8 prop if I can get them.

http://www.gravesrc.com/XOAR_LAMINAT...xor2080l3b.htm

That should work

thanks to all for the good advice, i will try a 20x10w apc and hope for the best

If you have 1-1/2" level, where's the problem? You don't intend to land propeller first, right? That's what landing gear and attitude are for.

3" of clearance with 3 point landings. That's enough clearance. Good luck,
Darrolair

"If you have 1-1/2" level, where's the problem?"

there is a joke in there somewhere but I'm not touching it

Jim

No joke, 'tis the truth. If you are landing and needing an inch and a half of gear spring to make the landing your not landing right. Especially with a 50cc aerobat. Everyone I've ever flown, and that's a lot of them. would float in if you controlled the speed with the elevator and the descent with the throttle. If they are bouncing 1-1/2" then they are being driven to the ground and pranged, not landed.

Think I'm wrong? Ask Jedijody how I generally land my planes.

He may have a light landing gear or live in a windy place.

I have a rule of thumb to have at least 3" ground clearance (4-fingers) when level. My planes are all in excess of 18 lbs. A slight bounce landing now and then should not kill my prop. We often land with heavy turbulence due to nearby trees.

Prop question:
Rule for changing to 3-bladed prop within same brand and have the same engine load:
go down 10% in diameter
go up 10% in pitch

As two of the planes I am flying are not rated for a 50cc engine, but I'm using DL 50s on both of them, I too require more prop tip - ground clearance. So I'm running 20 x 10 3-blade props. They perform great for me.

Yes, I can probably get by with the 1.5" clearance. We have nice new paved runways. I just need to keep the landings gentle and keep it out of the weeds.

Most of that will come from learning how thw plane stalls and how slow it will fly under power and in a power off glide. Often, those transitioning from smaller glow powered planes to larger gas have problems because they try to land like they did with the small planes. Too much speed. That makes things very hard to get on the ground with a larger plane. Another item effecting landing performance is an incorrect C/G. A forward C/G lands faster, and can float the length of the runway trying to slow enough for lift to cease.

""no Joke""

Tired Old Man,, I knew you were serous, it's just I had a dirty mind there for a moment [X(]

depends I guess whether there would be a prob. or not