I prefer tail-draggers and have long felt that, on grass at least, they are less troublesome than nose-wheels. Unfortunately, I like jets too and nearly all jet fighters are tricycles! The Gloster Goblin (the proof-of-concept testbed for Frank Whittle's first jet engine) and the earliest Me-262s had tail-wheels but those 2 are not on my "Wanna build" list.
At least part of the problems with tricycles is due to the fact that many models have nose-wheels that are poorly designed and poorly made. Many model designers do not seem to have wigged on to the fact that there is a reason why bicycles and motorcycles have their steering axis angled forward and not just straight up and down. It is the same with tri-geared full size aircraft, like Cessna’s and others. It's done that way so the line of the steering axis intersects the ground at a point ahead of the spot where the wheel contacts the ground. With the rolling drag acting thru a point behind that intersection, the wheel tends to remain straight and not just wander off in all directions. Some aircraft accomplish the same thing using a straight up and down nose gear leg but with the bottom part of the leg bent back so the wheel is still behind the point where the steering axis intersects the ground. If a bicycle had its steering axis straight up and down, you would have a heck of a time riding "no hands".
Besides the design, the model nose-wheel struts usually have several coils wound in, supposedly for "spring action". Now, how is the strut supposed to flex and spring back when the coils are wound so tight that they rub against each other? At least if the coils were wound with a small space between them, it would have a fighting chance. As it is, the gear legs just bend and take a set, usually at a point just above the coil. The temper of the wire on many of them is not ideal either. Many (not all) main gear struts are afflicted with too-tight coils too.
I have been complaining about this for 35 years or so but, alas, have been but a voice crying in the wilderness... (OK, admittedly, I have not written any manufacturers about it, but you must realize that this comes in Vol. XIX, Chapter 28, Sec. E, Paragraph 36 of "Tom's Pet Peeves", 2006 Edition, with addenda and updates. If I wrote this complaint, I'd have to write all the others too. I haven't got time to write that many letters. It's more fun to write stuff like this and squawk.)
In full size, taking some dual in a tail dragger for the first time was a rude awakening after having been trained on milk stools. I had read many articles, both for models and full size, about the "tail dragger challenge" for nosewheel pilots. Strangely, not one of them ever explained what the actual problem is. (The writers didn't know either. Some experts. See Vol XII.) But my instructor explained it well. On the tricycle, the mains and their rolling drag are BEHIND the center of gravity. Any side forces are automatically counteracted by the mains that want to stay nicely in trail. On the taildragger the mains are IN FRONT of the CG. Any slight deviation from rolling straight ahead tends to worsen. The light bulb went off. Of course! It occurred to me that this situation is much like a big truck; a tail dragger airplane rolling forward is like a tractor-trailer backing up - the slightest deviation from dead straight rapidly gets larger. The tricycle gear acts more like the tractor-trailer going forward.
These tendencies are more pronounced on a hard surface than on grass which tends to help the tail-wheel resist side forces a bit better.
On the full size the tail-wheel steering had springs (the full size really needs them) but that gave me a problem with the timing. The nose would start to swing, I'd stomp on a pedal, and nothing would happen right away. Getting worried, I'd stomp a little harder but just about then was when it was going to respond anyway and now I had too much and the nose would suddenly swing too far the other way. The cycle would repeat till the instructor grabbed it before I took out a runway light. Takeoffs were giving me more trouble than landings. But the landings were not trouble free either.
When landing a tricycle, after all 3 wheels are on, you get in the habit of mentally relaxing ("Ah, I made it!") You are lulled into a false sense of security. On a tail-dragger, the darn thing WAS behaving well up to the point when the tail-wheel came down or just a little after but that's just the point where the adventure begins. As the airplane slows and airflow over the rudder is reduced, its stabilizing force vanishes and just where you start letting down your guard the airplane suddenly starts getting squirrelly, trying to go every which way but straight. This is the reason for the old saying that you are not finished landing a tail-dragger until the hangar door is locked.
If I'd had the opportunity to continue flying the Citabria, I would have eventually developed the timing and the "feel" and would surely have conquered it, but things didn't work out that way at that time. I have no ambitions to ever go back to full-size flying but I still regard soloing a tail-dragger as my one bit of unfinished business in full-size.
These days I have no such problems with models and really enjoy the tail-draggers. I have even simplified things on several of my airplanes where I did away entirely with tail-wheel steering and just let it caster freely, steering with the prop blast over the rudder. This saved transmitting a lot of impact loads and vibration to the servo and to the rudder hinges. It worked out fine for most of the models - on grass, anyway. Granted, the steering was slightly less positive but only slightly - sometimes the tail-wheel has swung to one side and I have to goose the throttle some and hold opposite rudder to get the wheel to swing back but this is really not a big deal. How much precision do you really need in your ground handling anyway? We don't need to navigate a slalom course at our field so it's well worth it to save some building time and to save a beating on my servos and hinges. Really, I give up very little in ground handling. It just feels a little different.
There was one exception. On 3 or 4 airplanes it worked out as above but my XP51 was another story. (My Allison Mustang is an extensive kit-bash of an old Top Flight "Red Box" P51.) At first, this model taxied acceptably but it had another bad habit - it loved to dig its nose in the ground when landing, even after I corrected its first-flight nose-heaviness. I'd already bent the LG legs as far forward as I could (the entire wheel was ahead of the leading edge, let alone the axle). So I kept adding weight to the tail a little at a time and testing it with tight loops and tight vertical banks at high altitude to see if it was getting dangerously tail-heavy. I didn't quite get there but I was worrying that I was getting close to the point where it would start getting nasty and snapping without warning.
Then I noticed something - my Great Planes 40 size P51 was just about the same scale as the XP51 but its landing gear was a lot shorter than that on the XP51. And the GP 40 P51D had nice landing and taxiing manners. I figured out the reason for this (a subject for another time) and measured the legs on the two airplanes. The XP51 had 6" legs and the P51D had about 4 1/2" (give or take a bit). I bent up a new set of 5/32" wire legs for the XP51 about the same length as the ones on the P51D. Tra-la! Suddenly, the XP51 was making nice landings!
But there was another side to this coin. While it now landed without going on its nose, suddenly it would not taxi straight - it only wanted to swing around in a tight circle, one way or the other, and it was very difficult to stop it from circling. And when it finally did stop circling one way, it would just start circling the other way but it would not taxi straight or even in a larger circle. This was with a full 360 degree free-swiveling tail-wheel. It might benefit from limiting the swivel to, say, less than 90 degrees either side, or spring-loading it to the center, or both. That remains to be seen, but the point is that, of the 4 or 5 models on which I used a free-castoring tail-wheel, this is the only one that gave me a real problem.
I wonder if we are doing beginners such a big favor by adhering to the "Modeling Law" that says trainers MUST have nose-wheels. Nose-wheel steering of about 10 degrees either side of neutral works well on most models. Ever watch the circus when someone has the nose-wheel steering set up way too sensitive? People set Olympic records shinnying up flagpoles and climbing trees and diving behind cars...;-)
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