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Tail-dragger Tips & Tech

Tail-dragger Tips & Tech

Though many scale airplanes are equipped with tricycle landing gear, planes with tailwheels — tail-draggers — remain very popular. It is fair to say that most of the RC airplanes flown today fall into the tail-dragger category. In the air, tail-draggers behave just like tricycle-gear aircraft do, but on the ground, it’s another story altogether. Once you’ve built your first tailwheel plane, coping with its ground handling can be challenging. Here are some tips for taming that tail-dragger.

A tail-dragger has its balance point behind the main landing gear. At rest, this keeps the tail firmly on the ground, but once the tail comes up during takeoff, the model becomes inherently less stable. You must keep it lined up with the runway’s centerline, or its center of mass will try to shift around one way or the other, and this will result in an abrupt, tail-swinging turn known as a “ground loop.” If you let this happen, you may damage your model. The secret to taking off and landing a tail-dragger smoothly is to quickly use the rudder to correct any tail-swing. The sooner you correct it, the smoother your maneuver will be. Setting up the main landing gear with a little toe-in will also help to reduce tail-swing. It does take more skill to take off and land a tail-dragger, but it’s nothing that can’t be overcome with a little time and practice.

AFTERMARKET TAILWHEELS

This Sullivan Products tailwheel assembly is one of the best I’ve used for sport airplanes. It is available in four sizes; choose one to suit your model’s weight.

This tailwheel is typical of what you find in most ARF kits. It looks strong but does not prevent steering shock from reaching the rudder servo.

This tailwheel is supplied with the Great Planes CAP 232 and the Super Sportster ARF kits and is also available separately. It’s light and easy to install.

This Carl Goldberg Products tailwheel is another good choice. It comes with all the hardware, including the wheel, and is available in four sizes to fit airplanes weighing from 6 to 39 pounds. The bright plated finish will keep it looking new and free of rust.

One of the best I’ve used is this Ohio Superstar Products tailwheel. It’s available in five sizes for models weighing from 4 to 50 pounds. It is very rugged and has a very true-to-scale look.

You’ll find this great-looking tailwheel on the Pacific Aeromodel 27% Edge 540 T ARF. It has a fiberglass strut, a neat caster-wheel assembly and springs to absorb steering shock.

Though there are many tail-dragger models on the market, some kits include tailwheel hardware that isn’t as rugged as it should be. This is where the many aftermarket tailwheel assemblies come in.

One of my favorites for sport and non-scale airplanes is the spring-loaded Sullivan tailwheel. It’s robust and easy to attach with two screws. It has a spring wire to isolate the side steering loads from the servo and is available in four sizes. Another very good tailwheel is the sport design from Great Planes (GPMA2868). It is one of the best I have seen in ARF kits. A nylon bushing is mounted in a hole in the tail. The tailwheel-wire strut is mounted in the bushing with a wheel collar installed and retained by an aluminum clip. A thin wire that acts as a spring is soldered to and wrapped around the tailwheel strut and captured in a nylon bushing mounted under the rudder. The tailwheel assembly is plated, and it includes a wheel.

Carl Goldberg Products offers a new tailwheel assembly in three sizes for 6- to 35-pound models. It is a more conventional design and very true to scale. It comes with all the hardware, including the wheel. The strut is made of hardened, plated and polished steel, and the wheel caster comes mounted. A tiller arm is connected to the rudder with two springs, and this arrangement isolates the servo from steering shock.

Another excellent choice that has been around for years is the Ohio Superstar tailwheel. It also has a tiller arm and springs to isolate the servo from steering shock. It comes painted black and is available in sizes to fit small and large airplanes.

Be aware of the flimsy tailwheel setup that has the wheel attached directly to the rudder. This setup is acceptable for small models, but it is not good for larger planes. Because of the constant shock of ground steering and landing, sooner or later, a tailwheel that’s attached to the rudder will fail and damage the rudder and possibly its servo, too. A good tailwheel setup provides positive steering and ground handling, isolates the rudder from steering shock and should last a long time.

So, with your next model, take a closer look at the tailwheel assembly that comes in the kit. If it’s wimpy, there are plenty of aftermarket tailwheel choices that will improve your model’s ground handling and enhance its scale looks.

BY JERRY SMITH

Updated: July 16, 2015 — 4:08 PM
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6 Comments

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  1. What is toe in? and landing shock?
    I have a lot of trouble keeping the airplane straight on take off
    Will toe in help?
    Thank you
    Robert Skillman
    maavrick@sbcglobal.net

  2. OK’ Jerry lets see if I got this right. If I attach my tail wheel to the rudder, sooner or later both will fail. My second choice is just a tail wheel by it self, like the Sullivan or the Ohio Superstar, which should decrease the prospect of a ground-loop. But even with all of the above, I still have to compensate with the rudder, and you still have to consider the terrain( grass or pavement) and of course those’s nasty 2 words ” Wind Gust “. I seem to remember a device that attaches to the rudder and has a build in Gyro that compensates for the tail side to side movement. Have you ever heard of this device Jerry?. If you would like to PM me on this subject I can be found on RC Universe or RC Groups and also RCSB Radio Control Scratch Builders. Thanks for the article, I really enjoy reading Model Airplane News. Hank

  3. Good tips Im still wrestling with it though . Particularly the nose overs vs how long to hold the elevator so tail stays down . My trouble is letting the elevator off at the right time- its either nose over or leap up, tip stall, bang 🙁
    A gyro for the tail will soon iron out any tail swinging and toe in certainly helps.

  4. I have o casionally found that tactics utilized by the full size planes will have application to models…. soooooo… whenever I am taxi’ing, I hold full up elevator…. this essentially causes more downforce to be created. y the propwash over the deflected elevator… preventing a prop strike and also helping the tail wheel to be more effective … when taking off… an abrupt application of power can cause accidents… a smooth and gradual application of power keeps the gyro scopics and p-factor down to manageable levels

  5. Here is one of the best videos ever made to explain what y’all are talking about. If you want to cut directly to the part that describes the four forces acting on your propeller and on your airplane that produce the left turning tendencies on takeoff and climb-out skip ahead to time point 17:40. This video is brilliant!
    Nelson

  6. Sorry! I forgot to attach the link!!! Here it is: http://www.youtube.com/watch?v=0bP2MH3LqvI
    Nelson

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