Tailwheel a *****cat on grass but a wild animal on pavement

[azsportpilot]

At the risk of getting off topic,re bungees
Saggy bungys wont effect ground handling much but replacing sooner rather than later would be a good idea(there is a good video tutorial on You tube)don't make the safety cables too short(I think this has been well covered in this forum)

agreed, but I think in the case of this one, where one bungy is worn enough to be an inch or so lower than the other under the belly, translating to one foot lower at the wingtip...

I think it is imparting a slight right bank after the landing flare, after the plane slows down and settles onto the gear, it is essentially rolling out with a right bank

[av8rps]

I agree that maintaining bungees is important to minimize handling issues of your taildragger. But I've flown a lot of these little planes that have had a loose bungee on one side, as well as on both sides. Handling was only minimally compromised.

Aside from the tailwheel, the most common issue for bad (or almost impossible) ground handling is having one gear leg toed in or out while the other one is straight. That will give you all kinds of excitement. I have a spare 912 Kitfox 4 1050 (1200 now) in my garage that not only had a bad Maule tailwheel but ALSO had one gear leg that was toed out over 3/4 of an inch Over the course of its short 200 hour life that poor Kitfox had been damaged repeatedly from severe ground loops. The builder did a fantastic job rebuilding it each time with new parts that actually upgraded the airplane. But then he'd wreck it again in another catastrophic ground loop. After 5 rebuilds, he fixed it a final time and sold it, probably thinking he apparently wasn't man enough to handle a taildraggin Kitfox.

Now for the 2nd owner: The guy that bought it wasn't afraid of an itty bitty toy like a Kitfox, as he was a pretty experienced tailwheel guy. But after only owning it a short time, he decided to sell it.

I learned about this particular Kitfox when a friend contacted me about potentially buying it, and asked if I'd talk to the seller for him since he didn't know much about Kitfoxes. My friend said the Kitfox had been damaged but the repairs were top notch and it appeared to be a very well built airplane. So I talked to the owner, who went on and on about this being the hardest tailwheel plane he ever flew, admitting that even though he had a bunch of time in aerobatic tailwheel airplanes (most recently a Super Decathalon), the Kitfox scared him to the point he didn't want to fly it anymore for fear of wrecking it. It had so defeated him that he was absolutely insistent it would only be sold to an experienced tailwheel pilot due to liabilty concerns. I suggested if my friend were to buy it that he should trailer it home so I could help him figure out the ground handling problems, as I knew no Kitfox should be THAT hard to fly. But because my friend flew a Luscombe for a bunch of years and was confident with his tailwheel skills, and because the seller felt totally comfortable with his tailwheel credentials, he elected to fly it home instead of trailering it.

Unfortunately on the very 1st landing after purchasing it he ground looped it bad enough that the fuselage had to be put in a jig to replace bent longerons and some other tubes, and one wing needed ribs and tip replacement of the last 3 ft. The repairs were done so well that the airplane was essentially back to new condition except for needing covering (which it still needs). In the process of jigging the fuselage the excessive landing gear toe out was discovered. They fixed that at the same time of the other repairs. I bought the Kitfox from my depressed friend thinking of it as as essentially a parts project, but later realizing how nice of an airplane it really was, I decided to one day put it back in the air. So one day I tested the Maule tailwheel on it to see if it was worth repairing (another one slopped out in only 200+ hours), and sure enough, when leveled to simulate flight attitude and to take pressure off, it was fine in one direction, but would unlock when the other rudder pedal was pushed to the floor.

Moral of that long winded story? It was absolutely no surprise to me why that Kitfox was such a beast that almost no one could fly it. Between the issue with one gear leg being toed out excessively and a tailwheel that would easily unlock in flight in only one direction, I'm surprised anyone could fly it successfully. It's sad how many years and dollars it took to repeatedly figure out that there was something dramatically wrong with this plane. Even worse is that I believe it made at least two pilots doubt their own abilities, which may be the reason they both quit flying? And on top of all that, I'm guessing the one guy that actually had enough skill to fly it the longest without damaging it is probably warning everyone he knows to stay away from a Kitfox. The whole story is just a crying shame, knowing it could have all been easily avoided...

[av8rps]

I don't get it! I know of several guys who purposely installed their tailwheels without the locking mechanism, so the wheel is free castering ALL the time. they seem to have no trouble at all. They are probably not Maule tailwheels, but if free castering on landing were the only issue then those guys would be groundlooping on every landing.

Check out this ground loop video. This happens so fast that its hard to tell, but it looks to me like the tailwheel went into full swivel and as soon as it does it begins to shimmy excessively ultimately resulting in a ground loop. The main point being that a fully swiveling tailwheel will not work on an average airplane without some sort of detent or lock mechanism to keep it straight as you touch down.

https://youtu.be/HkDQBXH02fE

(Or maybe he just had the wrong app on his phone?)

[Dusty]

Great article (novel) very enlightening and with a Disney happy ending.
I think kitfoxes are a great airplane that sometimes get a bad rap due to issues you mention, as would any badly setup plane.

[Av8r3400]

https://www.youtube.com/watch?v=vgguzIAOs1s

If you watch this video you can see me make a landing in a blustery cross windy situation back in '12. Note the tailwheel and rudder, both visible. The wheel clearly comes unlocked during the landing with deflection of the rudder.

The problem is that the rudder stops were filed back too far in order to give more rudder authority. This pulls the wheel chain too far unlocking the wheel. I didn't want to weld more material back on the stops or rework the whole design (which I did on the Mangy), so I learned to live with the behavior.

Additional mitigating circumstances are: the spring is beginning to sag at this point which induced the shimmy (which can also cause an unintended unlock) and the added weight of the tail ski.

The main saving factor is the slow landing speed of the plane and that I was lucky. Later that year I did loop the plane, luckily at a very slow forward speed with no damage, from the spring-sag induced shimmy. A new 1-1/2" wide three leaf spring fixed that.

The early IV's had rudder peddles that as you pushed on one the opposite brake peddle came back toward the pilot. This only exaggerates the problem of the ground loop. I learned that if the plane ever started coming around, neutralize the rudder and get on both brakes hard and come to a stop. The brakes were far stronger than the puny little rudder on this plane.

[n85ae]

You would think this is rocket science, it's not. I wonder how many people
JUST hook chains to the rudder horns REGARDLESS of what tailwheel is on
there, and ever think for a microsecond about the ratio of rudder to tailwheel
throw?

Blindly accepting that if the factory did it a certain way, that it is right, is
a REALLY common problem. Their design, is based on what was working best
in their particular build for the particular person who test flew it. That does
not mean it is the best setup for every situation. BUT you hear it over and
over in these threads that "it was desgned that way, therefore it's correct"

I rode in an early model fox, and it was very difficult to taxi, and it's simply
because the tailwheel moved way too much in relation to the rudder. The
solution for that is to weld on new horns, or drill some holes.

You do NOT want a lot of tailwheel movement relative to rudder, or in any
case I'll correct myself, and say "you need the PROPER amount of tailwheel
movement to rudder movement, as related to the pilot flying the plane"

Nobody ever discusses this, but it's rather obvious if "you turn off the phone"
and use some brain cells.

Jeff

[azsportpilot]

I agree that maintaining bungees is important to minimize handling issues of your taildragger....

this is a great testimonial

I hope you don't mind, I copy/pasted and emailed this to my student/owner

We have had so much ground handing problems with his KF-3 that I'm starting to wonder if this is why the previous owner sold this plane to him

we have replaced the Maule with a Matco and it is much better, but still the most challenging TW airplane I have ever flown

the Pitts S2 was an angel compared to this particular KF-3 (flown other KF-3's and found them very predictable on roll out)

[Slyfox]

nicely said. I will restate this, land as slow as you can. If in the 3 point that's easy, you fly in 50mph over the numbers and hang over the runway about 2 ft. when it's ready you pull back all the way and stall land. when doing so you have a plane that is the slowest possible for roll out. and a pretty darn good landing to boot. after that you just taxi off. if you want you can add brake but I don't, in fact I have about 2000 hrs since I put brakes on mine, I just don't use them.

now with the tail wheel, I have the experimental tail wheel from spruce and it's cheap. I keep the chains real loose, that in itself will give you some differential so the tail wheel to rudder is a lot less, it works. when I flew remotes I would do similar stuff to knock down the throw on the tail wheel to rudder, that did wonders. it is no different with our kitfoxes.

land slow and don't have a bunch of throw on the tail wheel and make sure it doesn't unlock when you put your pedals all the way to each side, that's the ticket. happy flying.

[jiott]

https://www.youtube.com/watch?v=QtokU8mIDQk

If you haven't seen this video on tailwheel setup, I think it is the best out there. It is specifically for a Scott (Alaskan Bushwheel) but applies to most locking/unlocking types.

In my opinion, before you fuss with anything on the tailwheel itself it is absolutely mandatory that you make sure your main gear toe-in/toe-out is set up properly. Then make sure your tailwheel spring (leafs) have the proper angle to cause the tailwheel caster axis to lean slightly forward in order to prevent tailwheel shimmy. A violent shimmy can cause all sorts of ground handling problems. AFTER all this is done, then fuss with tailwheel setup as in the above video.

[Slyfox]

the only problem I have in landing is those cheap nanco tires are horribly out of round. bump, bump, bump once I touch. I know I need to change them out, but it's hard to do it to tires that have a bunch of rubber left. aaarg