Twin Commander
General Category => Airframe => Twin Commander Piston => Topic started by: JimC on May 18, 2018, 12:02:56 pm
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Why are there no short field STCs for the Twin Commander 500 series? I know it's already shorter than most twins when stock, but just about any twin with Horton, R/STOL or VGs will beeat a stock 500 off the ground.
VGs or cuffs on a 500 would be an awesome addition if they provided similar performance to other twins.
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How do you improve on perfection? ;D
Good question Jim. My .02: I don’t know of any aerodynamic devices of any kind that give any significant benefit on any model Commander. I’m not sure about gap seals, but I suspect they don’t help short field. May not hurt it, I don’t really know. The winglets are for looks and have a bit of a negative effect on fatigue life from what I understand.
The VG’s slow every plane down. If I had them on a Twin Cessna or Baron, I would take them off, personally. With the big wing and big effective controls on the Commander, I don’t think there is a need. Ask Adam. I think he operated his on a postage stamp more than once. 8)
The 500 is certainly no BN Islander, but it also has a lot more speed and comfort.
On the turbine side, a CFD analysis was done looking for ways to improve the design. I can tell you there really wasn’t much there. Noting we thought had enough benefit to develop, package and sell
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Flap gap seals hurt short field performance, is what I've been told. The gaps help airstream stick longer on the upper wing, which improves t/o performance.
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Ugh...Hate to hear that, Adam I wonder if I ought to remove my flap gap seals? I, basically, bought them twice (Glenn will understand when I say they were initially installed wrong...) ;-(
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Ed, don't they make it go faster, though? I guess it depends on which aspect of performance you are more interested in.
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Yes. Maybe a little bit. Sometimes it is hard to tell WHAT actually makes it go a little faster... Flap gap seals maybe... Certainly overhauled engines. However, I do know those flap gap seals create an extra step for the mechanics during the annual... I just had not heard that they hurt short field performance (I don't do a lot of that anyway...)
I am just glad I did NOT add the winglets when I had the work done in Tennessee a couple years ago... :-)
Ed
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The winglets look a little bit silly on a 500, in my opinion.
A while back, Twin Commander had some images of a turbine with large blended winglets, like those on a Gulfstream or Boeing. Did that do anything for cruise performance or climb? I assume they did some modeling, or maybe those were just images someone put together?
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Actually, only the longer ones would have any chance of it. The ones on our planes were never designed to increase performance I don't think. They just look cool for the company logo. :-)
Glenn