Tail wheels

[herman pahls 9]

I recently installed ABW 29" airstreaks on my model 2 Kitfox and the benefits out weigh the added weight and drag for my gravel bars.

I now need a bigger tailwheel than the small hard rubber Maule wheel that came with the kit.

I ordered a Matco (single arm)  9 inch wide pneumatic wheel which no longer digs trenches in the sand but raises my tail 4 inches.

The loss of angle of attack on take off and landing is very noticeable.

I plan to build a new fork for this tailwheel assembly to lower the tail but need this forums advice first before I start cutting up the assembly.

I will remove the steering arms and make it full swivel and steer with the brakes as needed.

In order to lower the tail I will need to design a fork that swivels more in front of the tire than at the 45 degree angle up and forward from the axle as it is now. 

It seems like most tailwheels including my sons ABW Baby Bush have the pivot in an approximate 45 degree orientation from the axle.

I got the idea from my neighbors RV-4 in which the tail wheel pivot is directly in front of the tire.

Other making sure the bigger tailwheel does not hit the rudder on hard hits, am I missing some important engineering issue?

This will be a whole lot easier and cheaper than having extended main gear built.

Thanks  Herman

 

[Av8r3400 1179]

How about just adding some flap on takeoff? That's easier yet.

To the full swivel wheel, I hope all of your bars are directly into the wind, all the time. These planes, especially early Kitfoxes, are very short coupled and do not have enough rudder. The Matco brakes that came with the kit are terrible, too. I wouldn't trust them for steering.

My advise: park your plane on the grass and drive over it with a truck. That will be a much safer and easier way to wreck it.

[akflyer 1427]

I went with the 8" wide matco and it made a huge difference on the beach as far as digging the trench, but I too notice the loss of AOA on take off and landing.  Even pulling in full flaps on TO and landing I still dragg the tailwheel in first.  If your not dragging the tail wheel, then your landing too fast, or faster than you could be landing, period..  I was going to start with shortening up the tail spring, with the dual leaf spring, its not like I am getting alot of cussion from the spring back there anyways.  I am guessing that you have already done a brake upgrade so you have plenty of power on the brakes to keep it lined up with a cross wind.

 

Have you seen the iron designs tail wheel?  I think it is alot like the one you are describing making.  Post up pictures of what you ahve going on and the mods you make, I am intersted in them for sure!

 

[herman pahls 9]

Leni

Thanks for pointing out the Iron Designs tailwheel.

I will let you know how my modifications work.

How do you feel about flying a full swiveling tailwheel not connected to the rudder?

That design is exactly how I wanted to modify my Matco to not lose angle of attack.

Regarding cross winds free swiveling tail wheels and having adequate brakes.

My Kitfox came with worthless go kart brakes which I upgraded to what I call the external mounted caliper versus the internal caliper I have seen on model 4 kitfoxes.

Even with 29" tires , the Matcos I am using are plenty to nose over at any time.

I have not yet flown with a full swiveling tailwheel that is not connected to the rudder so I will find out what I am in for.

It seems like most serious "big rock" pilots set up their tailwheels this way so it must work.

Herman

 

[akflyer 1427]

I kind of figured that the big rock long prop guys (Greg n Lonnie) were your inspiration for the free swiveling tail wheel.  On a Cub, it is no where near as short coupled as the KF or Avids are so it is much more forgiving in that manner.  You have quite a bit of TW time so I dont think it should pose any real issues for you as long as you have really really good brakes and you keep it straight.  Once it starts going on you, there can be NO hesitation to get the power in and stand on the rudder and brake and hope for the best!

 

[Av8r3400 1179]

... And hope for the best!

The truck idea is still easier and safer...

I've dropped springs off my tail wheel on my Kitfox landing with a full swivel. Not fun. Not even a little. I have grove double pucks and small tires, it was not enough. I needed a rudder the size of a dc3 to keep control. I went loop-around. Luckily no damage but for the seat cushion.

[akflyer 1427]

Larry, Did you get doug to make you a new seat coushion?  Brown interior tend to camoflage the evidence

 

 

Edit:  on second thought, that would be a waste of the nice coushions that Doug made