I have a wood frame EV97 that I have installed a Exceed Optima 450 - 2220 - 850KV motor on. I started with an 8 x 5 prop and the plane weighs around 2 pounds or less. All seems great and on the bench test and it seems like it has enough power but when I took it out to the field it would not get off the ground.
I can pick up some good speed but it will just not take off. I changed the prop to a 9 x 5 and I could get it airborn but it still seems way under powered. Is this motor just too small for this plane or is something wrong with my setup? I am still very new to electronic flying. Thanks for your help in advance.

What battery are you using?

Is the prop on backwards? The "curvy" surface should be forward. (With prop on backwards, you will still get forward thrust, but much less than optimal.)

Offhand, with 850 Kv and 8x5 prop on 3S battery, you're not going to get more than a pound or so of thrust.

Originally Posted by rafe_b

What battery are you using?

Is the prop on backwards? The "curvy" surface should be forward. (With prop on backwards, you will still get forward thrust, but much less than optimal.)

Offhand, with 850 Kv and 8x5 prop on 3S battery, you're not going to get more than a pound or so of thrust.

I think the battery is good. S3 1300ma 40C - I am sure the prop is on correct. When I go to the field I take three or four planes which I can get up in the air. This is the only one that I am having trouble with. Let me ask you this - The 8 x 5 prop was an old one in my box with nitro plane stuff. It was a white plastic prop much stiffer then the new 9 X 5 thin electric prop I just installed. Is there a difference in a nitro prop vs electric? The manual for the EV97 planes states to use a 8 X 5 prop. Could my problems have been from using a nitro prop type 8 x 5 that would not allow me to get off the ground and then using an 9 x 5 electric prop that is too big for this motor?

Prop too small or the motor too slow.
An 850 kv would need at least a 12" prop on a 2lb. plane.

Originally Posted by bartricky

Prop too small or the motor too slow.
An 850 kv would need at least a 12" prop on a 2lb. plane.

This. Actually an 11x7 should get you 2lbs of thrust so that will at least get it in the air. Top speed isn't going to be much over 40mph though. To get the speed and thrust you want for this plane from that motor/prop combo you would have to run it on 5s. I really don't think it would take that kind of power for long before you left a smoke trail. I think you need a motor in the 1000-1200kv range for this one on 3s.

Originally Posted by V2rider

This. Actually an 11x7 should get you 2lbs of thrust so that will at least get it in the air. Top speed isn't going to be much over 40mph though. To get the speed and thrust you want for this plane from that motor/prop combo you would have to run it on 5s. I really don't think it would take that kind of power for long before you left a smoke trail. I think you need a motor in the 1000-1200kv range for this one on 3s.

Ok last question for you nice people helping me out. Should I try a 11x7 prop this weekend with the current motor or change to a 3015-1020KV size motor I have on hand. Will this motor work for this plane or is it a little too big?

This was the only semi useful thread I could find on that model -

Hobby Lobby's EV-97

Used a Silver AXI 2212/26.

Originally Posted by eflightray

This was the only semi useful thread I could find on that model -

Hobby Lobby's EV-97

Used a Silver AXI 2212/26.

Ok - As motor sizes go. This guy states his AXI 2212/26 flys very well using a 10x5 prop. His motor is an 950KV. I think my 2220 is a hair larger then his 2212 so maybe if I go up to a 10X5 prop my plane will fly good as well, you think????

It would not get off the ground with a 8X5 - Airbone but like a tank with a 9x5 - So maybe slow but good using a 10x5 prop. This plane is just not all that large and a 10x5 prop will seem big on this plane.

I'd suggest finding a similar motor and see what sort of props people use on them. A similar motor means similar weight and KV, and I found one on hobbyking: https://www.hobbyking.com/hobbyking/s...dProduct=19037

As you see, even with an 11x4.7 the amp draw is well below the motors specified maximum. You'll need a bigger prop, and probably a longer nosewheel

Try to find a 10x7E, as long as you have enough ground clearance. If not, you need a motor with higher Kv.

With Kv of 850 on 3S, 10x5 will be struggling for enough pitch speed. His Axi has a higher Kv of 920, which is how he gets away with a 10x5.

10" might sound a little large, but 10-12" props are common in electrics around 40" span.

There seem to be no specs readily available on those Exceed motors - check the current with a wattmeter before flight! A 2220 sized cheap motor is likely going to be in big trouble over 15-20A. For example, the Axi 2212 limit is 12A.

The lesson here is that nitro prop size is a poor guide to electric prop size - you need to think of the whole system comprising number of cells, motor Kv and current capacity, and prop size.

It would help if you have a amp meter. But I agree with others if it is nto flying well then up the prop to a 10 X 7 or so and try again. Land after 2-3 min of flying and check to see how warm everything is. That will tell you if you are over stressing things. If you can hold your hand on the motor then you are golden.. go have fun.

Highflier