The winning time at Nationals in 2005 Division C was reportedly around 7 minutes but with a two gram max motor.
The plane could have 50 x 10 cm main wing but had an 8 gram minium weight as I recall. Bi - planes were allowed, but the experts told our team not to bother with a bi - plane that year, for many reasons. They were right.
Under the 2010 Division B rules, and by extrapolation, I would not be suprised to see someone break five minutes at the 2010 Wright Stuff event at Nationals given the 98 foot ceiling there. Someone will almost assuredly break four minutes.
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Lots of ideas, check the other threads on this bulletin board and last years archive.Draylon Fogg wrote:ok so i am haveing lots of trouble... our current plane is only doing about 1:23 at its best and im really starting to worry... any ideas?
But if you can tell us more about your plane and how its flying we can be a lot more specific. Without that, all we can do is repeat advice given in the past on this forum.
Info needed. Design features of the plane, weight, wing size, tail size, prop size and pitch, length between wing and tail, cg location, trim settings. How its flying, what size (width) rubber motor, winds, torque (if you measure it), flight profile (climb, cruise, descent, turn radius (increasing or decreasing through flight)) roll, dutch roll or stalls (different things) height achieved, etc.
Note, 1:23 means the plan is actually flying, so you are well on the way to success. That would win or place at many invitationals. Not all, but many.
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First, 11 grams is WAY to heavy, build lighter. Minimum weight is 7 grams and you need to be close to that (within a couple of tenths of a gram) to fly three minutes. Heck, 1:23 with a 11 gram plane is actually pretty good.
Second, BUILD LIGHTER!
OK, first plane flying, but rest not. Same design? Check for trim differences. Are the wing and tail and the same relative angles? Is the center of gravity the same? Are the control settings the same? Are the wing and tail warps the same? Sometimes subtle differences in building can make the 'same' plane fly very different and you have to sort that out during the initial trim sessions.
Flight pattern. Very short flight then dive. Several possible problems.
Are you glide testing with the prop and rubber band? If not, the center of gravity may be shifting when you add the rubber band.
Check the plane before and after installing the wound motor. Does the motor stick bend significantly pulling the tail down? If so you need a stiffer motor stick.
Does the plane first nose up as if trying to climb hard, then fall off and dive? If so you have a power stall, need some down thrust in your prop mount.
There is no such thing as a max SIZE wing, only a max span. The rules limit span to 40 cm, but no limit on chord. You need to be flying on a 10 to 12 cm chord wing for max times. Note there is a bonus for narrow wings, but only for states or nationals, you have to get there first so go for a BIG chord at regionals. And only experimental data will tell if the narrow wings are worth there bonus.
Same story for tail, no chord limit. New rule this year, but there is some advantage to be gained with a wide chord tail, just not much data yet on how much.
Length between tail and wing. Seems a little short. Will be harder to trim. Very small changes between wing and tail angle make much bigger differences. Tend to be less forgiving when disturbed (ie you hit the ceiling). It also won't take as much advantage of that large tail if you use it. Note, none of the designs I saw on the Pitsco site are particularly good ones for SO.
That's the hints and tips I can see from what you've provided so far. Info on prop and rubber combo would be useful too.
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