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Author Topic: Better landings - bigger wheels help?  (Read 3215 times)

Offline Dennis Toth

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Better landings - bigger wheels help?
« on: February 22, 2012, 05:55:48 AM »
Guys,
I am working not giving up a lot of points on landings due to bouncing. The gear is fuse mounted wire and can't be moved rearward. One thought I had was to use bigger wheels. I know they help for takeoff if you are on a rough surface, just wondering if anyone has any experience with this?

Also CG location, seems that a little nose heavy might help on landing with a light ship?

Best,               DennisT

Offline Allen Brickhaus

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Re: Better landings - bigger wheels help?
« Reply #1 on: February 22, 2012, 07:50:42 AM »
Can you make the tail gear longer, so the model sits more parallel to the surface?

Offline Juan Carlos Pesce

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Re: Better landings - bigger wheels help?
« Reply #2 on: February 22, 2012, 10:02:55 AM »
Not use wire, use an aluminum gear.
Regards

Offline Larry Cunningham

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Re: Better landings - bigger wheels help?
« Reply #3 on: February 22, 2012, 10:34:51 AM »
I always liked Lectra Lite (by Dave Brown) wheels, which are somewhat spongy. You can chuck them up on a bolt in a drill and use coarse sandpaper to round the tire edges to make realistic looking aircraft wheels. They wear out quickly on hard surfaces, but the lightweight tire material is soft and less likely to bounce. If you can easily replace them, it's not a big deal; available in various sizes.

L.

PS - I think they are called "Lite Flite" wheels now, available from Brodak.

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Offline keith varley

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Re: Better landings - bigger wheels help?
« Reply #4 on: February 22, 2012, 12:36:10 PM »
Dave Brown sells Lite Flight and also Lectra Lite wheels and they are both available from  Brodak as well as many other sources.The Lectra Lites are narrower , therefore lighter and wear faster. They both are made in treaded or non treaded . All foam wheels are not equal as far as anti bounce qualities are concerned, but for the RC community it is usually not of the same concern.One of the common makes in hobby shops lately is the Dubro , with the white spoke wheels.They have very hard rubber and for our particular use , not so good.Another extremely light common wheel is the Sullivan Sky Lites, also very hard foam that tends to give bounces. Of course a gear with less spring is much better , like a carbon gear or aluminum gear , but the correct location relative to the CG is still the most important factor and there is a lot written on this subject in the forums if you just search for it. Just last week I did some surgery on my Sultan and by moving the carbon gear back one inch,I made non bounce landings easier to achieve consistently.Keith

Offline Brett Buck

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Re: Better landings - bigger wheels help?
« Reply #5 on: February 22, 2012, 02:26:58 PM »
I always liked Lectra Lite (by Dave Brown) wheels, which are somewhat spongy. You can chuck them up on a bolt in a drill and use coarse sandpaper to round the tire edges to make realistic looking aircraft wheels. They wear out quickly on hard surfaces, but the lightweight tire material is soft and less likely to bounce. If you can easily replace them, it's not a big deal; available in various sizes.=

  I use the treaded version of the Lectra-Lite wheels, no alterations needed. BTW, if you do want to modify them, put them in a freezer for a few hours, firms them up for easier grinding.

   Brett

Offline PJ Rowland

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Re: Better landings - bigger wheels help?
« Reply #6 on: February 22, 2012, 06:10:42 PM »
I saw Bob Palmer fly years ago, and greased a landing that was surely worth 40 points - this was when he was far from his best..

I asked him about his landing technique and he mentioned the following which is great advice and one I still use today.

When the model is just about to make contact with the ground 1/2" off the surface apply a small amount of down elevator to suck it to the ground and hold it.


« Last Edit: February 22, 2012, 06:36:35 PM by PJ Rowland »
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Offline Mike Keville

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Re: Better landings - bigger wheels help?
« Reply #7 on: February 22, 2012, 07:01:21 PM »
When the model is just about to make contact with the ground 1/2" off the surface apply a small amount of down elevator to suck it to the ground and hold it.
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Offline Chris Wilson

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Re: Better landings - bigger wheels help?
« Reply #8 on: February 22, 2012, 08:29:40 PM »
Al Rabe type struts anyone?
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Offline SteveMoon

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Re: Better landings - bigger wheels help?
« Reply #9 on: February 23, 2012, 06:42:33 AM »
Dennis: There are, of course, several factors to consider. What type of plane
are we talking about? If this is a full size competition stunter then CG is a major
factor. If located correctly then wing mounted gear should be pretty easy to land
smoothly. When located correctly wing gear almost always have less bounce or
spring than fuse gear. As mentioned by Allen, a tall tail wheel wire can help.
This is a trick my brother and I learned from Bob G. His planes always sit almost
level. Makes it easy to just glide the plane in.

And, as P J mentioned, down elevator.
I don't necessarily give it any down while it's still in the air, but I am cranking in
down elevator almost as soon as it touches down. This has two purposes, keeping
the plane on the ground and stopping the plane from rolling as soon as possible.
When I judged at the Nats recently I could not believe how few people I saw doing
this. I saw a few get very close to having an overrun because they were close to begin
with then they landed and rolled and rolled and rolled. Come on man, put the brakes
on, dial in the down elevator!

Steve


Offline Brian Massey

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Re: Better landings - bigger wheels help?
« Reply #10 on: February 23, 2012, 09:12:31 AM »


Come on man, put the brakes on, dial in the down elevator!

Steve


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Offline PJ Rowland

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Re: Better landings - bigger wheels help?
« Reply #11 on: February 23, 2012, 04:28:07 PM »
Steve actually also added in something which is critical in my opinion.

Tail Wheel height. - I got this trick off someone else - try to get it sitting close to level, I think it has a better stance also.

I only apply down elevator when im between 1/8 ' and 1/4"  off the ground. On grass - im getting the wheels moving as they skim across the blades - concrete is a little trickier I like to crouch down as im gliding - perhaps wait until its 1/16th from the ground before I suck it down.
If you always put limit on everything you do, physical or anything else. It will spread into your work and into your life. There are no limits. There are only plateaus, and you must not stay there, you must go beyond them.” - Bruce Lee.

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Offline Ted Fancher

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Re: Better landings - bigger wheels help?
« Reply #12 on: February 23, 2012, 11:06:51 PM »
Steve actually also added in something which is critical in my opinion.

Tail Wheel height. - I got this trick off someone else - try to get it sitting close to level, I think it has a better stance also.

I only apply down elevator when im between 1/8 ' and 1/4"  off the ground. On grass - im getting the wheels moving as they skim across the blades - concrete is a little trickier I like to crouch down as im gliding - perhaps wait until its 1/16th from the ground before I suck it down.


PJ,

I always found a sixteenth of an inch too high for routine 40 pointers.  I like to bring it down to 1/64" and then take it that last 64th in small, equally spaced increments over the last third of a lap prior to main gear touchdown.

Ted Fancher

Offline PJ Rowland

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Re: Better landings - bigger wheels help?
« Reply #13 on: February 23, 2012, 11:42:32 PM »
Ted : I was never that great at judging my glide.

I was serious - esp on grass - I can see the wheels starting to get motion on grass prior to giving down elev. Im trying to give an idea of WHEN im applying down. It doesnt feel like im giving it once the model has actually touched down, but its not quite in the air either. Its a tiny amount above.  1/4"

Perhaps I need to try for the 1/64 Fancher technique for my 40 pointers :)
If you always put limit on everything you do, physical or anything else. It will spread into your work and into your life. There are no limits. There are only plateaus, and you must not stay there, you must go beyond them.” - Bruce Lee.

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 I Yearn for a world where chickens can cross the road without having their motives questioned.

Offline jim ivey

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Re: Better landings - bigger wheels help?
« Reply #14 on: February 23, 2012, 11:55:06 PM »
I flew with bob A Lot. I met him at griffith park in the early 50s. Doug "the traitor" moon, flew with us too, till he stated flying RC. thats why bob called him a traitor, He'd say he's not one of us anymore.  then he'd lafff LL~. bob was a funny guy, I knew him well. his favorite practice field was Burbank H.S. football field. It was blocks from where he lived. We also flre @ san fernando baseball patk on wednesday hights under the lights from dusk till 9 pm. all grass fields. 2" wheels. sometimes w wheelpants !. bob used open whells and his aluminum gear. ringmasters are hard to land good. like I said in an earlier post you need to be an inch or less when it runs out of flying speed.  if you can learn to  do that you'll have perfect landings.  jim

Offline W.D. Roland

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Re: Better landings - bigger wheels help?
« Reply #15 on: February 24, 2012, 12:51:30 AM »
The correct answer has been discussed on this site before.

will assuming that the landing gear wheel center line on Dennis airplane is well
 forward, at the LE or further from his description of the situation.

When the distance from GC to landing gear is excessive the bounce is hard to stop.
when wheels make contact with ground the center of rotation in now the wheel and
not in the neighbor hood of the CG, as lift decreases AOA increases to the point of making
enough lift to lift off again.=bounce
Holding the tail up with long tail gear will do a decent band aid.
This is a big problem in OTS and you are not allowed to correct it.

Somewhere in the piles of books scattered around here should be a % range of MAC that
would work in any normal situation. It will be somewhere behind L.E.(of MAC) and ahead of
CG. Pleas insert Balance point where CG is used in this post as CG is rarely on the center
line of airfoil.(I try not to confuse people.

Raising the tail even when landing gear location is correct WILL help reduce 'P' factor
on take off. Does your airplane turn in or give slack lines on take off even though it
tracks straight?
This seems more of a problem with the modern higher RPM engines.

This is what the problem on take off with a Sig Chipmunk/O.S..35s turned out to be..
thought the AOA on the ground was good until I actually measured it.

Dennis
When I was grade school age and flying Ringmasters and such mounting the wire geat in
a vertical(90deg from thrust line) or swept back some helped tremendously.
>>>>sometime the wire was simply bent so the wheel moved rearward helped alot.<<<

The real proper way to land tail dragger is 3 point where the wing is fully stalled at touch down and the stick is all the way back(full up)..
Easy with full scale and high wing loading R/C, Not so easy with our lightly loaded C/L airplanes.
Lots of practice and it can be done. I can do it some of the time.

Hope something in this helps.
« Last Edit: February 24, 2012, 04:19:21 AM by W.D. Roland »
David Roland
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Offline jim ivey

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Re: Better landings - bigger wheels help?
« Reply #16 on: February 24, 2012, 02:39:48 AM »
many of you know what a stearman biplane is. there was a guy @ san fernando airport that owned one. I watched him land a number of times. when he would land it, He'd bounce rhat thing 20-30 feet in the air several times before he could get it ro stick. 

Offline john e. holliday

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Re: Better landings - bigger wheels help?
« Reply #17 on: February 24, 2012, 08:34:16 AM »
That is because the normal reaction is to give up on the handle again and then down.   Also leading the plane a little helps with landings with the down elevator. H^^
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Offline phil c

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Re: Better landings - bigger wheels help?
« Reply #18 on: February 24, 2012, 08:54:55 PM »
The simplest trick to help grease in a landing I got from Joe Adamusko, hope he won't mind me letting the secret out.  Just as the wheels touch step towards the plane to release the line tension.  Nine times out of ten it will prevent a bounce even if the gear is too far forward, as yours seems to be.  There is a lot of energy in the tension and curve of the lines.  Stepping towards the plane releases that energy and it lets the wheels do their thing, since they aren't being dragged sideways.

Adding nose weight will also help, getting the CG lined up better with the wheels.  You'll have to figure out if you can stand what it does to the plane in other parts of the pattern.

phil Cartier


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