Oops! NEw landing gear required.

My favorite way to make breakaway landing gear is to mount it with nylon bolts. I've torn off nylon-mounted gear a few times with no damage to the plane. The trick is to use bolts that are small enough to break.

Yeah, I hate it when my 1/4-20 nylon wing bolts get protected by the airplane coming apart all around them.

BTDT

I've never understood the logic of making break away landing gear. Why not just practice landing? It's lots more fun and reduces or eliminates the need for problematic break away landing gear.

Ed Cregger, NM2K

I guess I agree, Ed, because I just repaired it so it was as solid as I could make it. I was out to the field this evening and one of the guys had a Four Star that is apparently built in such a way that the gear breaks away if the landing is too rough. The guy ripped the gear off the plane in a semi rough landing tonight and commented that its kind of a pain in the butt. I, therefore, built mine to not break away.

Harlan

Its for while you are practicing, Ed ;-)

I got caught the other day, flying a model I normally simply land dead stick in calm air. Some guys wanted to see it and it was turbulent.

It stalled at 10 feet and smashed its nose, largely because the landing gear ripped out the part of the model it was attached to.

Subsequently I went back on the sim and tried it again after repairs, and determined that it needed to be brought in under power, airspeed substantially above stall speed, and 'flown' onto the ground, under those conditions.

I don't like landing gear that breaks off under normal landing conditions, and most of the time I have solidly mounted landing gear anyway. One time in particular, however, I built an Airmeister biplane with nylon bolts holding the landing gear on. The elevator failed because of a cheap clevis, so I pulled it back to idle and brought it in kind of fast over a plowed field. The model suffered nothing more than broken bolts, a failed clevis, and a fair amount of dirt. Since then I haven't had many landing gear problems, and mostly I don't crash or land hard. But when I've cracked up planes it's mostly been because of some catastrophic failure causing total destruction.

On Fri, 21 Sep 2007 10:49:18 +0100, The Natural Philosopher wrote in :

There is some rule that full-scale pilots use for landing in gusty conditions.

I don't know exactly what it is. Something like adding enough airspeed to compensate for the worst possible gust that might be expected.

You seem to have discovered that rule for yourself.

Marty

Yup. And when I proudly announced it., everyone was quick to point out that they indeed flew like that all the time, and surely everybody knew that?..

Humiliating isn't it?

:-)

Ohhh,,, Ohhh,,, I KNOW this one ;-)

you make a breakaway connection so that at the end of a perfect flight, you can grease a landing, and hit the ONLY gopher hole on the runway which causes the landing gear to shear off, This drops the nose into the ground breaking a nice $10 prop, in the meantime, the gear flips over on it's back just in time for the wheels to rip a nice big hole in the bottom of the wing on both sides of the fuselage, which flips the gear over a couple more times so that it can rake and scrape a bunch more covering off the bottom of the fuselage.

THAT is why you put break away landing gear on your plane,

BTDT, four star 60

bob

On Fri, 21 Sep 2007 14:54:24 +0100, The Natural Philosopher wrote in :

Only if we view learning as a zero sum game.

You learned something important and valuable and you shared it with us.

WELL DONE!

Marty

| I don't like landing gear that breaks off under normal landing | conditions, and most of the time I have solidly mounted landing gear | anyway.

The problem with a break-away landing gear is that if it does break away, it tends to tear up the tail or in an extreme case, the wing -- on it's way to tearing up the tail. That's how my US40 died ... I did a downwind landing due to a fun-fly and while my landing was just fine, there was a hole I didn't see, which ripped off the landing gear, which tore up the wing, then the tail ...

It was repairable, but I gave it all away rather than bother ...

So if you do use nylon bolts to break away, you want them to break before the rest of the plane does, but not too easy -- or they'll do more damage than they prevent. I don't know if it's worthwhile or not.

In any event, the US40 landing gear mounting location is known to be weak, and it tends to break just like the original poster's did, even in landings that weren't that bad. So they tend to get beefed up early in the plane's career.

Another weak part is the stock engine mount. At least the original one ...

---------------------------

Ouch! I hear the voice of experience in your words.

Ed Cregger

"Martin X. Moleski, SJ" wrote

I think it is adding 1/2 the difference between the steady wind and the gust speed. If you had 10 gusting to 20, you would add 5 to your landing speed.

I'm sure there are some full sized airplane flyers that will correct that, if it is not the right formula.

"Doug McLaren" > wrote

I like to make my landing gear mounting very strong, but make the landing gear "bendable" but only in the very hardest "carrier style" landings, known to most people as "crashes." ;-)

On Fri, 21 Sep 2007 19:25:25 -0400, "Morgans" wrote in :

That sure sounds about right.

Very likely.

And we can't be that precise, given the general lack of telemetry from our planes. I will try to keep the rule in mind that I need more speed in gusty conditions. I think I knew that, but I appreciate the reminder.

Marty

Ed, Most of us aren't fortunated enough to have a perfectly smooth runway , and , I don't know anyone who "greases" them in all the time. Break away lamding gear with nylon bolts is the way to go , IMO. Much rather have the landing gear break away than to rip the bottom aut of the airplane. Many of us at the field where I fly use this setup. It works for us..

Ken

Should you find that your nylon bolts still will not break, but remain in place with the whole plywood piece and then some still coming off, drill a fine hole straight down the bolt. Some even make a little "nick" in the bolt with a fine file.. Todays ARF planes seem to need this feature more than ever before, what with heavier planes and Schnürle 46 engines up front where there once used to be cross flow 20s... Heavier & faster approaches every season, and bigger and bigger garbage can at the field !

Staffan

Sweden

Now that you mention it, that's why I had breakaway gear on my Airmeister years ago, but I haven't used it since. We used to fly from grass fields back then, but for the past ten years I have been flying from a very nice paved runway in Kansas City.

I might have to go change my ways again, depending on where I end up flying here in Springfield. I haven't gotten into the local scene yet....

I haven't even *used* my landing gear yet. All I have to fly in is a hay field.