Richard39

My Feedback: (14)

I just swapped for a Something Extra and it has been fun to fly but has a wing incidence problem... It has about 2 degrees negative wing and elevator incidence... This causes the airplane to stick to the runway during take off ... then rocket up at a steep angle... She flys nice and lands great but everone at the club is convinced that the take off problem is due to the negative incidence... What do you think and please suggest a solution... This something extra has the mid wing connected by plastic/nylon ties/connectors and the wing is somewhat permanetly connected... I have looked into the fuse servo area under the canopy and can see one nylon tie that is pulling the wing together at the front....There is also the metal wing tube visable... Is there something else holding the wing together.... I ask because I can not see under the very long servo tray (6 inches of solid 1/4 ply)....... I would like to take the wings apart to correct the incidence but do not want to proceed until I can obtain more information on the wing... Thanks..

jsn

My Feedback: (8)

Richard,

If the builder followed the plans you should be able to cut the Zip tie, undo the Aileron servo connections and pull the wing half's off... If he built it "his way" your on your own

John

David Cutler

The incidence might have been caused by the fact that the dowel that stops the wing from revolving is not, in fact, in the center of the chord. That is, it's not symetrical, and its possible to build it wrongly and build in unwanted incidence by installing the inner most rib upside down.

-David C.

Richard39

My Feedback: (14)

I have talked to the builder and he has given me a song and dance answer.... I believe he built the airplane to give extreme 3 D and therefore the negative incidence... maybe... I do not know... Is there only the one nylon tie to hold the wings together? Thanks

P-51B

My Feedback: (5)

Unless he glued the wings to the fuse, the nylon tie (in your case) should be all that is holding the wings together.

Wings of Peril

You stated that the model flies well so the negative incidence is probably part of the design. I have a .90 powered Edge 540 that has noticeable negative wing incidence (you can see it just by looking at the wing slots). It would not take off unless it hit a bump on the runway. I bent the tail wheel strut to the lowest possible position and it’s OK now but disappointingly, it will never do a realistic wheel take off. The tail just won’t fly on roll out; it needs to be stuck to the ground to give the wing sufficient angle of attack. Similarly, all landings are 3-point. I’ve seen some other tail draggers at the field whose owners installed larger tail wheels or kept the struts long in an effort to improve ground handling on a grass field. Sometimes this is a mistake. Similar problems can develop on tricycle gear models when the nose wheel is too short, pointing the nose down, but these planes can still rotate into a good angle of attack because the tail has room to drop down to the surface- but a tail dragger cannot rotate any further than the tail wheel position allows.

Richard39

My Feedback: (14)

Thanks for all of the replies and assistance.... At this point I believe that I will not make any incident changes or attempt to make changes as long as the airplane flies as good as it does... I plan to shorten the tail wheel distance to the ground... it now holds the fuse up about 2 1/2 inches from the ground... by lowering it will change the angle of attack by both the wing and horizonal stablizer and should help on the take offs... I will try that in a couple of days.... Thanks...

jsn

My Feedback: (8)

Richard I think your on the right track... if it fly's good and your only complaint is the long take-off roll/jump into the air you can lower the tail as suggested or get some taller main gear. I have a Global Freestyle that has... had the same problem... with the stock short gear you had to go WFO on the ground and hold a bunch of elevator to coax it into the air... and then if just JUMPED into the air... I used some gear from a GP extra that not only gave me more prop clearance it gave the wing the angle of attack needed too take off in a more normal fashion.

John