Spanish Kitfox III, help with stall speeds

[JorgeEC-YUQ]

Hello everyone,

this is Jorge from Spain. Let me say at first this is a nice forum and it's been a great source of information, thanks!

I recently became the proud owner of a beautiful Kitfox III (EC-YUQ) and I'm going trought the first hours of flying and familiarization with my new machine.

I would like to hear some of your comments regarding stall speeds on this model since, after reading some of the threads in this forum and the manuals, I find myself having a much MUCH higher stall speeds.

I didn't had the time to properly test the plane so I'm talking about aproximate figures of 45 mph full flap / 50 mph flap 0º (in dual), producing a gentle stall with some buffeting with the stick fully back.

This is forcing me for space suttle-high speeds on approach to avoid running out of "back stick" during the flare and a REALLY hard two wheel landing.

Could any of you guys provide some light in this matter?

Thanks in advance!
Jorge

[Dusty]

Check your c of g. If too far forward u will get a gentle stall,More of a high sink rate with buffet .In this condition it is easy to run out of elevator in the flare.
I had the same problem, but like a forward cg so i put a gap seal on the elevator.The flare can be much later ,the wing fully stalls and no more embarrassing skips!

[Av8r_Sed]

Hi Jorge,
My stall with full flaps is 33 mph indicated. I have also added a gap seal on the elevator which helps with flare at touchdown.

My short final approach speed is currently 50 mph with full flaps. The sink rate at this speed is very high and if I don't give it a little power at the flare it does hit hard. When I give it a little power it almost but not quite three points. The good thing is it gets you down and stopped in a very short distance this way. I understand this is fairly normal for a stock Model III.

[Olle1975]

Hi Jorge,

have a look at this video about a Kitfox III stall Performance.
There you could see the Performance about a power off/on - stall and
stall with 10 degree flaps.

https://www.youtube.com/watch?v=qEOdkYCn5rE

Olaf

P.S. Which engine did you mount?

[JorgeEC-YUQ]

Thanks for your comments!

I was thinking it could have something to do with the elevator indeed, so that might help.

Unfortunately I am working abroad So it will pass some time until I can put some tape in the elevator and see if that helps ... I will keep you posted.

Olaf, It,s running a rotax 912 80HP

Thanks for the help!
Jorge

[cgruby]

Hi Jorge, I too have a type III and am still getting used to flying this type of airplane. My airplane lands three point very nicely with plenty of up elevator available. This airplane power off has a pretty substantial sink rate at 50 mph approach speed. There is very little energy left during the flair to arrest this rate. If you control the rate of descent with the throttle it lands a lot more gently. Good luck.

Cheers,

[Jono]

Those stall speeds are quite close to my Model IV speeds. I only run-out of back stick in the flare with more than 3/4 Flap on (very rarely use flap in the fox anyway). For me it is easier to just limit myself to 3/4 flaps as I rarely need to land on a postage stamp :)

[JorgeEC-YUQ]

Hi guys,

I finally tapped the gap on the elevator and it became a totally different plane.
The flare is much better now with more elevator power, lower stalling speeds, etc... It is even gliding better and I can lift the tail static standing on the brakes!

So that helped a lot, big thanks for all your inputs!

Jorge

[Olle1975]

Could you post a pic how do you tapped the gap on the Elevator, please!?

Olaf

[SkyPirate]

elevator relaxed hanging down tape the top side,,holding the elevator up tape the bottom side .
on mine I pushed the tape down into the gap so both top and bottom strips of tape meet each other this puts the seam of the tapes meeting closer to the hinge point

[JorgeEC-YUQ]

Hi Olle,

I am out of home for 3 more weeks, I will post some pics then.
But basically I did as Skypirate mentioned. Tape upper and bottom side ...
I was planning to do something wich would look more "professional" but since the tape is doing the job ... It will stay!

Jorge

[JorgeEC-YUQ]

As promised, some pictures of my "quick fix"...

[Monocock]

I also found that gap tape on the elevator of my Mk 3 made a huge difference.

I used 3M book binding tape that is clear, and doesn't show. I did the entire length along the elevator, but left gaps for the hinges. I also used SkyPirate's application method which worked really well. :)

I didn't do the rudder, as I don't feel as if it needs it. Happy to be persuaded otherwise.