Short field STCs

[JimC]

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.

[Bruce Byerly]

How do you improve on perfection? 

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.

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

[Adam Frisch]

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.

[Badger]

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...)  ;-(

[donv]

Ed, don't they make it go faster, though? I guess it depends on which aspect of performance you are more interested in.

[Badger]

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

[donv]

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?

[ghancock]

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