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Help!!! Engine placement

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Old 03-26-2002 | 07:14 PM
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From: Yucaipa, CA,
Default Help!!! Engine placement



I am hoping you funfly pilots with experience with more than one funfly airplane will be able to answer this. I need to know what engine placement will effect slow flight to allow the slowest speed for landing. Assuming that the CG is the same (a bit back to allow all the fun of funfly) is it better to have the engine closer to the wing or farther forward.

Assuming that I have a plane that I can move the radio equipment and engine to keep the CG at the same location and not add any weight, will I get better control and slower landing speeds with the engine farther forward or as close to the wing LE as possible. The plane does have flaps or flaperons, depending which switch I flip.

The plane I now have, a SPAD based on Don Incoll's Wasp flys absolutly great except that it tends to land rather fast and doesnt just mush at the stall point as I have seen other planes do. I fly in a big field near my house and have only a 10 - 12 foot wide curving dirt road to land on so I am trying to get the landing speed down so I can drop it in where I want it (preferably at my feet). This plane weighs around 4Lbs so I dont think weight is the issue.

Any input would be appreciated.

I just love the 'Outside the box' flying of funfly.
Old 03-26-2002 | 07:41 PM
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Default Help!!! Engine placement

I'm no expert... but I have found that an easy landing plane is one with a very low wing loading... So going light is key. I haven’t found that engine placement is as critical as getting the CG where you want it. All things being equal... The longer the moment (engine and tail) the more pitch stable it will be, and the shorter the moment, the more unstable it will be... which is desirable with a funFly!!!

One other thing... If you get the CG too far back, the plane will be very pitch sensitive and be difficult to land... ask me how I know

Post some pic's of your plane...
Old 03-26-2002 | 10:22 PM
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From: Easley, SC
Default Engine Position

When you have a short moment in the front of the aircraft, regardless where the CG is, the aircraft will be difficult to land with this kind of aircraft. It will naturally want to drop the tail. When you attempt to move the CG forward to compensate for the short front moment, the aircraft will 'Hunt'. It is like riding a roller coaster ('been there-done that'). If the SPAD is not 'hunting' today, then, like Paul said, the only thing that you can do, short of changing the wing design, you'll have to lighten up the aircraft. Seems to me the SPAD has a flat bottom wing, or at least a semi-symetrical wing. This wing design lends itself to slow flight. If you are looking to Elevator the aircraft in, then you need a different wing design. One with a thick foil with a blunt leading edge. Remember that that SPAD is a combat plane, that has aerobatic capabilities (I believe).
Lighten the aircraft up if you can.
Let us know how you make out.
Old 03-27-2002 | 12:54 AM
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From: Yucaipa, CA,
Default Help!!! Engine placement

Here is a pic of the SPAD in question (if I did this attachment thing right). It is a 'Wasp' made out of coroplast. It weighs abount 4lbs (my scale is not very accurate), maybe a bit more. The plane will hover, knife edge, flat spin... all day long. It has a very blunt lead edge, 47in span, magnum 46 with a tuned pipe. I had a spad sport plane with a symetrictical airfoil that was not as thick as this one and it slowed very nicely and it weighed more than this.

I have flown a friend's TT Giles 200 funfly and it really slows down. It weighs about what mine does. And when it gets close to stall it just mushes. Mine has a sharper stall effect even though it has all the funfly characteristics.

I was thinking that perhaps that if the CG is in a set location and the mass in front of the wing is longer, as opposed to having less mass in front of the wing, that it might effect the flying characteristics, especially at slow speeds.

I definately understand about having the CG too far back. The first few flights it was so far back as to make the plane unflyable. I was lucky to get down in one piece.
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Old 03-27-2002 | 04:41 AM
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From: Bartlett, TN
Default Help!!! Engine placement

Hey SkyPig... That looks pretty cool... How did you get the coroplast to form that nice leading edge?? And how did you make the fuse?

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