Microaero vortex generators on 8KCAB

Halhayden

Halhayden

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Aug 4, 2021
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Location
Prescott, AZ
Has anyone installed the Microaero vortex generators on their 8KCAB? I fly my 1976 Decathlon into some short back country strips and someone suggested that they would help when using a slower landing speed. However, I also enjoy doing basic aerobatics in the plane and don‘t want to add VGs if they will negatively affect my loops and rolls.
 
I'm a little surprised they'd get the STC for the 8KCAB since it's an aerobatic airplane but there it is on the list. Have you tried calling the company to ask if they have an opinion about it?

I can't imagine VG's would affect aerobatics except for slow speed elements like spin entries. Getting a clean stall break to enter the spin might be more challenging. Loops and rolls though shouldn't be any different but I don't have first hand experience so take it for what it's worth.
 

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I can’t imagine they would actually help in aerobatic flight.

As for landing/takeoff, the three point attitude of the Decathlon is quite a bit lower than the slow flight attitude without VGs. If you bring a Decathlon in at maximum angle of attack, your touchdown will be tail first with a bone-jarring touchdown on the mains a split second thereafter.

If you are actually able to fly slower with VGs, a touchdown may result in main gear damage, or worse.

You need a 7GCBC, or a Scout. Those wings are already at a higher angle of incidence.

All reasonable Decathlon landings are wheel landings, done above stall speed, even when 3-point.
 
My VG’s seem to help low speed ops. Mebbe it’s all in my head though. It will only stall power off if I “horse” the nose up. With a pax in the rear seat it seems to stall a little better. Prolly aft CG. OK it will stall power off if I hold full back pressure for awhile.
 
Bob - Thanks for your input here. I'm a little confused about your statement that " are wheel landings, done above stall speed, even when 3-point. "
Don't understand how I can do a 3 point landing above stall speed... can you elaborate a bit?
 
If you slow a Decathlon to stall speed just above the runway - let's say the lowest wheel (the tailwheel) is two inches above touchdown - your main mounts will be about a foot off the runway. The tail wheel hits and the mains come crashing down.

Put VGs on it, and in theory it stalls at a higher angle of attack. Crash!

A normal 3-point landing in a Dec is well above stall speed. The Decathlon is not an "off airport" machine. I have landed in fields, but they need to be smooth and long.

I canot make it any clearer than that. You do not land a Decathlon the same way you land a Citabria or Cub, unless you want to do lots of landing gear bolt inspections.
 
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