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-   -   Incedence on bipe wings?? (https://www.rcuniverse.com/forum/kit-building-121/201348-incedence-bipe-wings.html)

onewinglow 07-19-2002 09:21 PM

Incedence on bipe wings??
 
I am building a Lanier Ultimate Pitts and wondering what the incedence should be on the lower wing and the upper wing. Are they the same or alittle different. I have heard conflicting stories on setting up bipe wings. What are your thoughts.
thanks
Scott

PHILLCO 07-20-2002 10:41 AM

Incedence on bipe wings??
 
WELL HERE IT GOES. I HAVE THE DIRECT CONNECTION 10-300 BIPE. THERE MAY BE A DIFFERENCE BETWEEN IT AND THE PITTS BUT I SET MINE UP LOWER WING 0 DEG TO THE STAB AND THE UPPER WING AT 1/2 DEG NEG. MINE FLY'S GREAT. I HOPE THIS HELPS.

onewinglow 07-20-2002 01:45 PM

Incedence on bipe wings??
 
Thanks for the info, That was what I was told before, 0 bottom but couldn't remeber if it was positive or negetive degree on the top.

Rodney 07-20-2002 03:59 PM

Incedence on bipe wings??
 
I have four large bipes and all required about 1.5 degrees less angle of attack on the upper wing than the lower wing had. If possible, try to leave your plane so that you can make minor changes on your first flights. It is amazing how as little as 1/2 degree change on the upper wing can effect the flyability of the model.

MAJSteve 07-20-2002 04:20 PM

Incedence on bipe wings??
 
From the looks of all the posts I've seen in various forums it seems that either pos or negative on the top wing will work, just so long as they're different than the top.

From my experience, this has got to be true because with both at 0, the darn things will never fly straight and level for more and a few seconds.

The stab seems to be a critical issue. With non-aerobatic style bipes, it seems the consensus is a couple of degrees positive will work the best.

Aerobatics seem to be set at 0 for everything with some right thrust for the engines.

Big_Bird 07-21-2002 07:56 PM

Incedence on bipe wings??
 
1 Attachment(s)
On my Giant Aeromaster the stab and both wings were set a 0 degrees per the plans. I found that when balanced in the middle of the recommended range, I had to carry some down elevator trim to fly level. Also the plane exhibited a pronounced pitch sensitivity. I shimmed (two 1/4" washers for a total thickness of 0.123") the back of the top wing to produce about 1.2 degree of negative incidence with respect to the bottom wing. This fixed the pitch sensitivity and I was able to take out the down elevator trim.

FYI, I used the designers measurments for the engine of 1.5 degrees of down thrust and 2.0 degrees of right thrust. These seem to be fine.

The plane is really fun to fly now. Also, knife edge flight is really simple now with no elevator correction needed for very straight flight. Very little down elevator is required for inverted flight.

I like to think of the 1.2 degrees as providing a little stability like tow in on a car provides. Try it, I think you'll like it.

Ken


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