Wing drop with vertical pull
06-19-2005, 10:28 PM
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Wing drop with vertical pull
Hello all
Many aerobatic planes that I have owned have had a troublesome characteristic that I would like to better understand. When pulling elevator to point just beyond the low rate limit suggested by the manufacturer, the plane rolls more-or-less violently to the right. This does not happen when pulling quickly through that position - such as when pulling 3D rates to effect a wall or initiating a hover or elevator. It just happens when pulling the right/wrong amount to an elevator position beyond low rates but at the lower end of the 3D window of elevator travel. I have seen this in 40 size plane, dramatic with older Hangar 9 Edge 540, with GP Patty Wagstaff Extra 300, Lanier 120 size Edge 540. I really don't see this as an accelerated stall and snap, but I guess that may the case. For those of you who know what I am talking about - its quite distracting as this sudden unwanted event in 3D flight mode near the ground is a bad thing. Interesting (to me) is that I do not get this with Hangar 9 330L 33% Extra - so that is the only plane I like to fly these days. I would really like to understand what causes this and particularly if there are measures to correct or avoid in first instance.
Thanks for any thoughtful comments.
RJM
Many aerobatic planes that I have owned have had a troublesome characteristic that I would like to better understand. When pulling elevator to point just beyond the low rate limit suggested by the manufacturer, the plane rolls more-or-less violently to the right. This does not happen when pulling quickly through that position - such as when pulling 3D rates to effect a wall or initiating a hover or elevator. It just happens when pulling the right/wrong amount to an elevator position beyond low rates but at the lower end of the 3D window of elevator travel. I have seen this in 40 size plane, dramatic with older Hangar 9 Edge 540, with GP Patty Wagstaff Extra 300, Lanier 120 size Edge 540. I really don't see this as an accelerated stall and snap, but I guess that may the case. For those of you who know what I am talking about - its quite distracting as this sudden unwanted event in 3D flight mode near the ground is a bad thing. Interesting (to me) is that I do not get this with Hangar 9 330L 33% Extra - so that is the only plane I like to fly these days. I would really like to understand what causes this and particularly if there are measures to correct or avoid in first instance.
Thanks for any thoughtful comments.
RJM
06-20-2005, 07:56 AM
#3
RE: Wing drop with vertical pull
Ihave lots of hands on experience with the EDGE you mention and the 33% H9 Extra.
First - the small models you mentioned are all woefully overweight and simply --as Paul noted , stall out easily.
The 33% EXTRA -done correctly is darn good at not stalling out or dipping a tip.
size and wing loading REQUIREMENT are far different.
The 33% H9 models all can easily weigh about 22-24 lbs -no reason to be heavier than this .
This sticks wing loading about 30 0z ft -+ a bit.
The wing loading per se -is not much different than the smaller models -BUT the smaller models need to have a much lower loading to be anywhere near as well loaded for aerobatics .
more like 25 ozs ft.
Always kicking to the right , suggests an unbalance in weight and or trim (including rudder and elevator ).
First - the small models you mentioned are all woefully overweight and simply --as Paul noted , stall out easily.
The 33% EXTRA -done correctly is darn good at not stalling out or dipping a tip.
size and wing loading REQUIREMENT are far different.
The 33% H9 models all can easily weigh about 22-24 lbs -no reason to be heavier than this .
This sticks wing loading about 30 0z ft -+ a bit.
The wing loading per se -is not much different than the smaller models -BUT the smaller models need to have a much lower loading to be anywhere near as well loaded for aerobatics .
more like 25 ozs ft.
Always kicking to the right , suggests an unbalance in weight and or trim (including rudder and elevator ).
06-20-2005, 11:54 AM
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RE: Wing drop with vertical pull
One way to check is to do an inside loop from upright flight and then an outside loop from inverted flight. See which wing tends to roll to the outside. If it's the same wing panel (say, the model's right wing panel), then you have a weight problem. If its one wing panel in the inside loop, and the other wing panel in the outside loop, then you have a misalignment somewhere (wing warp, ailerons not aligned, bent fuse, rudder off, elevators not aligned, and so on).
06-20-2005, 12:32 PM
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RE: Wing drop with vertical pull
When I am sure my plane is assembled correct, I have used this procedure to determine if my elevator throws are correct and to make adjustments. It will also tell you if you are compensating for a twisted aileron or not.
ORIGINAL: Bax
One way to check is to do an inside loop from upright flight and then an outside loop from inverted flight. See which wing tends to roll to the outside. If it's the same wing panel (say, the model's right wing panel), then you have a weight problem. If its one wing panel in the inside loop, and the other wing panel in the outside loop, then you have a misalignment somewhere (wing warp, ailerons not aligned, bent fuse, rudder off, elevators not aligned, and so on).
One way to check is to do an inside loop from upright flight and then an outside loop from inverted flight. See which wing tends to roll to the outside. If it's the same wing panel (say, the model's right wing panel), then you have a weight problem. If its one wing panel in the inside loop, and the other wing panel in the outside loop, then you have a misalignment somewhere (wing warp, ailerons not aligned, bent fuse, rudder off, elevators not aligned, and so on).
06-20-2005, 10:44 PM
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RE: Wing drop with vertical pull
Thanks all for the info and comments. I don't think its a lateral balance issue as I have loaded one wing and then the other with weight without any real effect with respect to this issue. For whatever reason, its much more difficult to creat this effect with outside pushes!? I have seen this on so many planes that I don't believe it is just a wing warp or mismatched incidence problem. As has been pointed out ... for larger planes not an issue - so I understand comments re wing loading. Has anybody tried inboard stall strips or similar approach .. or is that just way too honky?
Thanks
RJM
Thanks
RJM
