tricycle landing gear?

What are the advantages and disadvantages of tricycle landing gear? It seems that they are not extremely popular but they are used by some (the Pathfinder, for example...).

LAST EDITED ON Jun-11-03 AT 01:42 PM (CDT)
 
Disadvantages would include limited length for a two bladed prop, and good 3 blade props aren't always plentiful. Possibly close prop to ground clearance which could make flying off of grass a problem. Of course some of the tall tailwheeled modern ships sit at about the same angle as a ship with a nosewheel. I think a lot of it could be people just liking the looks of a tailwheel more. Would a nose gear be a problem on a piped ship?

Advantages include;

Easier smoother takeoffs and landings. A good place for the low time pilot to gain some extra points in the pattern.

No nose over in grass, either on take off or landing.

In all but the tallest grass fields, at least with the Pathfinder, there's adequate clearance for an 11 inch two blade prop, which is what most .40's use.

I'm wondering why everything is spinning around?

You forgot the two greatest disadvantages: Weight and drag. Since an experienced modeler can do a creditable job of take-offs and landings on a two wheel set up, most opt against the three wheel gear. Why carry the weight and the drag around if it doesn't benefit you and does cost?

The weight and drag don't seem to bother the Pathfinders I've seen.

>The weight and drag don't seem to bother the Pathfinders
>I've seen.
>
>catdaddy

It's relative. If you don't have to add the extra ounce of two (or drag) and if it doesn't benefit you, then why do it?

Now, if you went to one wheel, these don't take off or land as well. There is good reason to use two and not one, but not a good reason to use three instead of two (well, most do use a small tail wheel).

There's also the vertical CG issue. That's a lot of extra weight carried pretty far below the vertical CG

LAST EDITED ON Jun-11-03 AT 05:23 PM (CDT)
 
One thing about the PathFinder is that it was designed to use trike gear right from the beginning. It uses the setup as part of it's design.

I've owned several PathFinders, and am currently flying the Brodak kit version. It isn't hurting at all in the flying dept. because of it's nose gear. Where it's hurting is at my end of the handle. I really need to get out and practise more.

I still believe it's easier and smoother to get good, high point, takeoffs and landings, consistently through varying field conditions, with a proper trike gear. Especially for the lower time pilot.

Main, two wheel gear can indeed be great in the hands of a proficient pilot. When it's set up correctly, main wheel, tail up, landings are a breeze, but when the gear isn't placed correctly, landings, especially, can be a problem. The extreme example of poor main gear placement includes most of the OT , and not a few of the Classic designs.

Main gear, when it's set up properly for pavement, often has a problem with grass. Many planes wind up on their nose, or if too fast, on their backs. The solution is to have two sets of gear, one for pavement and the other for grass. With Trike gear, it works fine in either condition.

Another item to consider. It's very difficult to damage a prop with a trike geared ship. The other day, while landing the Twin Flight Streak on grass, the plane flipped over and broke both props, even though the props were setup to have them horizontal when the engines quit.

Now, having said all the above, I figure it all comes down to personal preferences. I like Trikes. I feel that when the gear is part of the design, the extra drag and weight, is of little consequence. I believe that the advantages outweigh the disadavantages.

Of the several PathFinders I've seen, modified for main gear, none have exhibited any increase in performance over the stock versions. I have seen more bounced landings with them though.

I also enjoy flying my main gear ships, when the gear is properly placed, But, I do notice that, unless the grass gear is on, I tend to nose over in the grass upon landing. Since some of our local contests are flown off of grass, this hurts the landing scores, and in the case of flipping over on it's back, can really hurt your pattern scores. In light of this, I always make a set of grass gear for my main wheel planes.

Palmer had at least one early T'Bird with trike gear that he used to win the Nat's with. A lot of Nat's winners used trike gear, beating all comers at that time, so they can't be all bad.

My advice, If the plane was designed for one type of gear, either type, use what it was designed for.

I'm wondering why everything is spinning around?

Good explanation, John.

I used to have some grass gear, but somebody talked me out of it.

I put tricycle gear on a Flite Streak about 42 years ago. I had some negative incidence in it. The airplane didn't have enough elevator authority to take off until it hit a bump. It looked pretty silly rolling around the circle at high speed.

John wrote: "Since some of our local contests are flown off of grass, this hurts the landing scores, and in the case of flipping over on it's back, can really hurt your pattern scores. In light of this, I always make a set of grass gear for my main wheel planes."

I guess I need to re-read the rules. Hmmmm. It can score zero points, unlike the rest of the maneuvers. I guess if it flips over, it's a zero. Does this then mean you lose pattern points? Never thought about this before, and luckily never had to deal with it.

Regarding the trike gear, I have seen quite a few good fliers "tick" their prop on takeoff in windy weather at contests and on hard surfaces, even an Expert or two. The dinged prop ALWAYS kills the performance of the model, and while the prop may be repairable with a bit of sanding and re-balancing, it really is risky to try to continue the flight in the mood to fly the pattern. Nuh uh! Don't do it! Seems to me that a trike gear is a nice security blanket when using those expensive CF props. Also, don't neglect to learn the correct place to setup for starting. You do NOT want to be facing downwind. You want to be on the downwind side of the circle or slightly into the wind. If anybody can figure out how to put a nosegear on a piped or rear exhaust engine, let me know. The only thing I can come up with is mounting it on the cylinder head. Not impossible, but not the best solution, I hope. Steve

>John wrote: "Since some of our local contests are flown off
>of grass, this hurts the landing scores, and in the case of
>flipping over on it's back, can really hurt your pattern
>scores. In light of this, I always make a set of grass gear
>for my main wheel planes."
>
>I guess I need to re-read the rules. Hmmmm. It can score
>zero points, unlike the rest of the maneuvers. I guess if it
>flips over, it's a zero. Does this then mean you lose
>pattern points? Never thought about this before, and luckily
>never had to deal with it.
>

My understanding, and I could be wrong here, is that you would get zero for the landing, and lose pattern points. You've essentially "killed" the pilot.

>Regarding the trike gear, I have seen quite a few good
>fliers "tick" their prop on takeoff in windy weather at
>contests and on hard surfaces, even an Expert or two. The
>dinged prop ALWAYS kills the performance of the model, and
>while the prop may be repairable with a bit of sanding and
>re-balancing, it really is risky to try to continue the
>flight in the mood to fly the pattern. Nuh uh! Don't do it!
>Seems to me that a trike gear is a nice security blanket
>when using those expensive CF props. Also, don't neglect to
>learn the correct place to setup for starting. You do NOT
>want to be facing downwind. You want to be on the downwind
>side of the circle or slightly into the wind. If anybody can
>figure out how to put a nosegear on a piped or rear exhaust
>engine, let me know. The only thing I can come up with is
>mounting it on the cylinder head. Not impossible, but not
>the best solution, I hope. Steve

I've seen this happen as well. depending on how bad the prop was damaged, as to how much damage can be inflicted on the plane due to vibration.

As for your question on how to mount a nose gear on a rear exhaust, muffler, or pipe ship. Yes, it can be done. I did it on my full bodied PathFinder. The one I flew at the 95 Nat's. I think you saw it at the first COLD contest.

The nose wheel is mounted to the cowl. It's taken some hard bumps over the years, and still doing it's job.

I'm wondering why everything is spinning around?

>Good explanation, John.
>
>I used to have some grass gear, but somebody talked me out
>of it.

Hi Howard. Are we talking about the same kinda grass?

>
>I put tricycle gear on a Flite Streak about 42 years ago. I
>had some negative incidence in it. The airplane didn't have
>enough elevator authority to take off until it hit a bump.
>It looked pretty silly rolling around the circle at high
>speed.

I know you already know this, but, I'll say it anyway for those who might not.

Trike gear, when not properly positioned, can cause some problems. Problems such as you described. I've found the best setup is to locate the mains just far enough aft of the CG to barely keep the plane on all wheels when sitting with an empty tank. On most PF's the tail will stay down if you give it a slight push down on an empty tank. This equates to about 1/2" to 1" behind the CG location.

The key is to not use negative incidence, as more power pushes the nose down harder. Set up at 0-0-0, and the mains located as explained, the plane will stay on the ground as long as you want it to. With negative incidence, or the mains too far aft, it takes a lot of speed and elevator to start rotation. Once the plane starts rotating, the speed is up there, and the plane jumps into the air. Very difficult to control.

Set up correctly, it just takes a slight pressure, hardly more than thinking it, and the plane will lift smoothly and very predictably.

Landings are also easy as there's just a slight rotation just before touchdown. Once touched down, a slight amount of down will lock the plane on the ground. The likes of Bart K. likes to roll out on the mains, holding the nose wheel off the ground for a while. This can be dangerous though, I'll explain.

Perhaps you saw how I messed up my landing in Classic at the Regionals. My Excalibur, two wheels, had the gear setup for pavement. When It touched down soo smooth, I was sure I would get close to maximum points for the landing. I was rolling it out on the mains for almost 3/4 of the circle. I thought it had slowed up enough to put the tail down and get it stopped. Boy was that a mistake. I still had too much speed, and was heading into the wind. When I dropped the tail, the plane took off and rose about 3 feet into the air before it stalled and nosed in. 10 points. Yuk.

BTW, it was good to see you in Oregon.

I'm wondering why everything is spinning around?

Same kind. A guy stopped by Seattle to pick up a 767, saw the gear in my basement, and took it. He did give me a cold in trade. I won't name names, but the gear was on the plane that took second at the NW Regionals.