Stall proofing the Kitfox – Answer found?

[rogerh12]

A while back I made a posting entitled “How can I keep my kitfox from stalling & spinning in too ????” as I was concerned about stalls and spins, and the possible results on me and the plane. This posting drew 57 comments, but no real answers outside of “keep your airspeed up” and “keep your turns coordinated” . Well, looking through some other post, I appear to have found the answer to my original question (at least on the Kitfox-4). While this solution appears to not 100% “completely” stall proof the kitfox, it does make it highly stall resistant. This posting was actually on Vortex generators. Here is the posting (and notice the effects of VG on stalls):


The vg's that come from Kitfox come with everything you need, right down to a little tape measure. They have vinyl decal material that is a template that you apply to the wing. It makes placement really easy. As far as placement, they're installed further apart near the wing root so that the inboard will stall first and the stall will progress outboard. I installed mine at 8% of cord after talking with the owner of Pacific Northwest Aero who is the owner of the company that the Mcbeans get them from.

Some people don't have much good to say about the vg's, but they made such a dramatic difference in slow flight. The plane is rock solid with very little mush. If you power off stall, with the stick all the way back, the airplane stalls then breaks, and instantly recovers without ever letting the stick forward. Power on the break is more abrupt with little warning. You used to be able to spin mine without much trouble, just stall it uncoordinated. With the vg's, it took three attempts before I could get it to spin. I would stall it uncoordinated and as the wing would drop a little bit it would recover. I've never flown something where you could stall it with the stick back and the ball off to the side and it wouldn't spin, or at least spiral. The plane just kinda slides off to the side, stalling and recovering. I was finally able to get it to spin by stalling it then kicking the rudder abruptly.


This posting was by Nick W. on his Kitfox-4-1200, which is the same plane I am building. I keep thinking VG just seem too good to be true, but when I read Nicks account of the test flight, I have to kinda believe it’s possible to really do something about stalls in the kitfox.

What do you think, too good to be true?
Roger

[Esser]

Airplanes stall and airplanes spin. If the VG's help in slow flight and help with wing drop go for it. But I would never rely on anything but your own capabilities. If you are worried about spins, go take a unusual attitudes course. You'l have a load of fun and walk away a better pilot.

[mr bill]

I owned an Ercoupe in the early 80s that could be made to do a slight stall, but only with power. The secret was a collar around the control wheel shaft, that limited up elevator travel. No stall, no spin. Very simple.

[DBVZ]

I owned an Ercoupe in the early 80s that could be made to do a slight stall, but only with power. The secret was a collar around the control wheel shaft, that limited up elevator travel. No stall, no spin. Very simple.

Interesting. So on a stick plane, just adjust so the seat limits travel? Also limits climb.

[Av8r3400]

Will also keep you from flairing to land.

[t j]

I love to slip my kitfox when needed to lose altitude on final approach so always worried about being cross controlled that close to the ground. Rich stowell has calmed my fears on that.

Here is some good information on stalls and spins.
http://www.richstowell.com/documents...lSpinMyths.pdf see #3 about slipping and spins.

If you want to get more detail here's a 90 minute webinar on the above topic. at about 6 minutes in he gives very good detail on the dreaded base to final stall spin.
http://bcove.me/ka4iiz5c

[rogerh12]

Esser;

That’s good advice on the extra training. They teach Aerobatics only 30 minutes from here, so I think I will take a barf bag and get some spin recovery training in.

Also, I got my LS license in an ercoupe. Because the elevator travel was limited, I could never really get it to land very slow though, no full stall landings at all, it would just run out of elevator travel first.

Thanks for the input
Roger

[Wheels]

I have them on my plane. The stall is just as mushy and benign as your post explains. I have not tested the spin characteristics as my plane is not approved for spins. I did just complete 10 hours of aerobatic training and will say that if you are a new pilot like me, that training with a good instructor is worth all the time and effort. Just make sure he's more interested in teaching you safety and recovery than impressing you with all his cool tricks. Motion sickness slows your learning.

Maybe someone on the forum can tell you what plane you might train in that has similar spin characteristics to a model IV. I used a Decathlon and you practically have to be a weight lifter to get it to spin, but when it does ... Ride em Cowboy!
My VGs are "Land Shorter."

[kitfoxnick]

What is all this fuss about stalls anyway? With the power to weight ratio of the kitfox a little stick foward and a shot of power and she snaps right out of it. I enjoy flying my plane low and slow and the vgs definitely add to the safety margin but there is nothing to be afraid of.

Nothing can take the place of practice. I think if people would spend the same money on fuel that they spend on their latest wizbang anti stall gadget they would be much better pilots for it.

Stepping off the soap box now

Nick W.

[rogerh12]

Nick;

What’s all the fuss about stalling a kitfox you ask?

Lets see if I can say this delicately.....The Kitfox is super strong and protects the passengers in a steel cage so well that it’s a very safe plane to land badly in. You have to really build up a lot of energy to get enough of it transferred to the passengers to cause real injury. If you check the NTSB database, most (in fact almost all) of the fatalities in a kitfox have occur after a stall & spin near the ground as this is one of the few ways you can build up enough energy to defeat the built in safety features of the Kitfox.

Therefore, theoretically, if you can make the kitfox totally stall proof, you could drop the fatality rate of the plane down to darn near zero for all future flights. And that would be a wonderful thing (and thus all the fuss over the VG and their effect on the kitfox stall charicteristics).

Roger