Tail Dragger Question

[Edwards Aircraft]

I am building a Mirage Celerity. It is a plane that has conventioal gear (with a fully castering tail wheel). I am concerned about directional control on take-off, especially with a cross wind. I've heard from another Celerity owner that this can be a problem. Would I benefit from making the rudder larger? Or would a larger surface area just make the problem worse? I would probably have to Increase the width of the control horns also to compensate for the longer rudder arm and associated deflection loads.

 

[Riggerrob]

What about the military solution that involves locking the tail wheel straight just before take-off?

 

[BJC]

I am concerned about directional control on take-off, especially with a cross wind. I've heard from another Celerity owner that this can be a problem.

I would talk to several Celerity pilots to see if they all agree. Lots of tailwheel airplanes have been deemed to be difficult to control by pilots who were inadequately trained.

BTW, there was a Celerity at Oshkosh a few years ago that had been modified to use an RV-6 canopy. It was a very good looking airplane.


BJC

 

[don january]

Remove Tail wheel and mount a skid like a stock Taylor-monoplane has

 

[BJC]

 

[Victor Bravo]

Fully castering tailwheels work just fine. All you need is a mile square grass field, where you take off and land into the wind at all times. That's why they were called "airfields"... 100 years ago. Fast-forward to 1950, and you start seeing narrow strips of pavement ("airstrips") that are not automatically pointed into the wind, and the castering tailwheel is not longer sufficient without a way to steer it.

 

[Dan Thomas]

The de facto tailwheel is a steerable castering tailwheel. A free-castering tailwheel is a recipe for lots of trouble, and most airplanes that use it also have a locking function for it. Even some steerable castering tailwheels have locks, such as the McCauley tailwheel used on some Cessna 185s. That's a $10K tailwheel, by the way. And rare.

So one should use what works elsewhere. There are some good homebuilt tailwheels like the Matco. A steerable tailwheel allows you to control the airplane until forward speed is high enough to let the rudder take over. A free-castering wheel leaves you at the mercy of the wind, and on whatever braking you might be able to use to keep it straight, but braking on takeoff just makes the agony last longer.

The steerable-castering tailwheel has a mechanism to let the wheel rotate freely during ground maneuvering. Tight turns while parking and so on.

And as BJC implies, training is necessary. Find a good tailwheel school and get a bunch. It's cheap insurance for your new airplane. Ask for bounce and swerve recovery training, too. And for wheel landings as well as three-pointers. And don't solo until you have mastered crosswind operations.

 

[n45bm]

I am building a Mirage Celerity. It is a plane that has conventioal gear (with a fully castering tail wheel). I am concerned about directional control on take-off, especially with a cross wind. I've heard from another Celerity owner that this can be a problem. Would I benefit from making the rudder larger? Or would a larger surface area just make the problem worse? I would probably have to Increase the width of the control horns also to compensate for the longer rudder arm and associated deflection loads.

How about changing the tailwheel to a steerable one? Might only require springs between the rudder control horn and the tail wheel control horns.

 

[gtae07]

View attachment 107641

Looks a lot like an RV cowl too.

OP, take a look at RV tailwheel assemblies (including the aftermarket options). They're steerable but can release for full castering. I can't find any clear images of a Celerity tailwheel assembly but you might be able to find something steerable that will adapt

 

[rv7charlie]

Boy, I never knew what an Ace I am; 180+ hrs in a Globe Swift, and something north of 700 hrs in a couple of RV4s, all with a free castering tailwheel. ;-)

Seriously, it really is more about training/practice than anything else. My Swift partner had removed the chains, so I just flew it. Both the RVs had the old style non-breakaway tailwheels, and were royal pains to push backward, so I took off the chains.

I'm not saying that free castering is 'best', but it can be a reasonable compromise. My current RV6 has a proper breakaway tailwheel, so the chains are still on.

In my opinion, the biggest issue for tailwheel pilots is fear of the brakes. We're grossly overtrained to stay off the brakes except at a slow taxi, so we leave a very useful tool in the bag when we need it. For evidence of that, look at all the incidents/accidents that happen after a tailwheel steering link breaks. In the vast majority of those cases, the brakes would have been able to easily handle the situation, but the pilot didn't have the 'muscle memory' to use them during rollout.

Is the Celerity *designed* with a free castering tw? if yes, that would seem to indicate that it would be controllable, but I've never flown one. But adding control horns to the rudder and a steerable tw shouldn't be too difficult, if you're really concerned.

(BTW, I'm no Ace; just good training and lots of practice.)

Charlie

 

[BBerson]

Yeah, brakes work on takeoff too, when needed, just a quick jab or two.

 

[Toobuilder]

The need for steerable, lockable or castoring tailwheels depends on the airplane. My Rocket is no problem to land or take off with the tailwheel swiveling like a shopping cart. My Hiperbipe was a nigtmare with tight chains and often full application of one brake.

Depends.

 

[Mcmark]

Mike, My Hiperbipe landed on rails, only when I had gusty Xwind did it get fun. Even then a wheel landing kept it straight.
The S1C I started flying early on could be landed with the tailwheel unlocked but it took a lot of brake to handle down around 20 mph. Stinger/tailwheel was installed out of plumb.

 

[Bill-Higdon]

IIRC the Baby Great Lakes used a locking full swivel tail wheel

 

[BBerson]

A taildragger should never have any toe-in. Toe-out is ok or straight is ok.

 

[Toobuilder]

Mike, My Hiperbipe landed on rails, only when I had gusty Xwind did it get fun. Even then a wheel landing kept it straight.
The S1C I started flying early on could be landed with the tailwheel unlocked but it took a lot of brake to handle down around 20 mph. Stinger/tailwheel was installed out of plumb.

I got used to the Hiperbipe and with time I became quite comfortable landing it in virtually ANY reasonable weather/wind - but it was not the pussycat that some make it out to be. Also have a few other HB pilots that admitted the same thing about theirs (when nobody else was listening). I did have to replace the engine mount after a groundloop and the legs were set up "by the book" with the new mount.... It was still one of the most challenging airplanes I've ever flown. It's no RV, thats for sure (and some people struggle with those!)

 

[Mcmark]

Believe it or not THE most challenging taildragger I've flown was the Smith that I had.
Easy off and great in the air but the most evil biacth trying to get it stopped.
I went thru the gear top to bottom and never got it right. I think the spring gear was too narrow at the wheels and it went where it wanted.

 

[Edwards Aircraft]

View attachment 107641

Yes, this is Gary Rene's beautiful example. He is the one I've talked with quite a bit. His is also one of only 4 Celerities compleated and registered. So, there is little chance to get any stick time in one. I'm guessing that an RV6 would be a close comparison. My Celerity is built according to origional design with retractable gear (tailwheel included). Gary built his with fixed gear and therefore was able to use a steerable tailwheel as described with control connections to the rudder. I'm not sure how I could make mine steerable. It has a small detent in the straight forward direction. This may not be as effective as a locking mechanism. I may look into that. Thanks for all the input. Does anyone have an opinion about my question of building a larger ruddder? It is still in primer and now would be the time to make such changes if I am going to make them.

 

[Mcmark]

That detent will lock it. Cessna 195 is that way as are a bunch of the warbirds ie the AT-6/SNJ. IIRC the Beech 18 and the DC-3 are too.

 

[BJC]

Does anyone have an opinion about my question of building a larger ruddder? It is still in primer and now would be the time to make such changes if I am going to make them.

Assuming that the vertical stabilizer structure is adequate to deal with slightly increased lateral forces, increasing the rudder chord at the base, and tapering it to the original chord at the top would add area and, to my eye, improve on the already pleasing aesthetics. Be certain to maintain the specified degree of mass balance.

That mod would improve rudder power. Other things that might come into play for yaw control on initial takeoff acceleration: Changing the thrust line. A typical offset is 1.5 degrees to the right. Increase the maximum right rudder deflection. I would want at least 22 degrees. You are already considering a locking rudder. My airplane takes lots of right rudder with initial power. I have a spring-linked steerable tailwheel, and never have had problems keeping it straight. I know other pilots who will not fly a single seat Pitts without a locking rudder. That is part of the reason I questioned the adequacy of pilot training. Note that, with a metal prop (high moment of inertia flywheel) at TO RPM, a rapid lifting of the tail will generate a strong left yaw. Technique is important.


BJC