LEU & LE XL Bent or Damaged Landing Gear Pictures and Informaton send my way.

[Sparrow]

Hi Eaglers,
 
Sparrow here.  I am interested in receiving any and all pictures of landing gear damage with a brief explanation of how the damage occurred and the tube diameter and wall thickness. 
 
I am only interested in the LEU and the LE XL because of sizing constrains imposed by 103.
 
Thank you in advance for any information you pass my way.  Please capture the suspension, if any and the wheel and tires you were using at the time.
 
If you don't desire to display on the forum you can email direct to me at 11leake11@gmail.com


Sparrow

[Steve]

http://www.angoraaffaire.com/leu/id48.htm

The first screen of the link above modifies the 20" fiber wheel LE gear into survival mode unless you drop it in - the gear should bend under those circumstances or a longeron will...

If you make the back brace tubes to sta 3 of 4130 .035 wall 5/8" tube there will be more strength and about the same weight...

A few flyers have put 1" tubes up to Sta 2 but the majority have settled on 3/4" .049 4130 - IMO 1" is excessive...

At another point screening down on the same link will be the Bike Disk Brake conversion that has been copied successfully many times...

Gears are usually folded in the early flying hours while a GA trained pilot gets a feel for the low mass effect and the requirement to fly well into ground effect before rounding out for a 3 point landing... Carrying some power right into 3 point attitude initially is advised until you get a sense of the UL regime...

[Sparrow]

Thank you Steve.  That is all good information.  I like the modifications and I agree the point is to sacrifice the gear and not the fuselage.

Sparrow

[Sam Buchanan]

The entire gear set on XL-58 is 5/8" x 0.035" 4130.........no shock absorber springs, just the Black Max low pressure tires. So far there have been no bent gear legs during three flying seasons, but the plane has not been abused.

[Sparrow]

Thank you Sam,

I had read you did this earlier in my study and it is good to know this is working.

I hope to head off any future issues by knowing the experience of the group.

Thank you,

John

[Sam Buchanan]

John, I hope what I'm about to write is taken in the spirit of encouragement that I intend....

The key to not damaging gear legs on an Eagle is to know how to land the plane. The lightly-built Eagles are intolerant of poor airmanship, but will reward the competent pilot with a long, uneventful service life. Assure your skills are at the point where you can land a plane and not merely arrive (semi-crash) and you won't have problems with the gear as designed.

[Steve]

John, I hope what I'm about to write is taken in the spirit of encouragement that I intend....

The key to not damaging gear legs on an Eagle is to know how to land the plane. The lightly-built Eagles are intolerant of poor airmanship, but will reward the competent pilot with a long, uneventful service life. Assure your skills are at the point where you can land a plane and not merely arrive (semi-crash) and you won't have problems with the gear as designed.

If you fly the plane over-gross, and many do, the gear will need to be beefed up, sooner or later...

[Tom H]

Sparrow, we built our LEU's gear pretty much per plans, but used a 3/4", heavy wall (not sure of wall thickness) tube for the axle, which never was damaged.  Used the 20" bike wheels.

During taxi/crow hop testing, we bent the front gear legs.  The center portion of the front gear leg bowed upward.  I think what happened was the spring struts bottomed out during a hard landing, and put a hard pull on the axle end connection, causing the bend.

We straightened the legs, and added a reinforcement tube, parallel to the front leg, but standing off by about an inch or so.  No problems after that.  I've attached (I hope) a pic in which you can see the gear leg reinforcement.

However, like Sam said, the trick is to land properly.  After we got the hang of it, our landings were smooth and soft, and the reinforced gear was probably not needed.  If we get Treehugger flying again, I'll try to reduce weight, and the reinforcement will probably be removed.

Sorry, no pics of the bent gear, but hope this helps.

Tom H

[weasel]

I had a loss power issue long time ago on out LE. Gear was built to plans with die springs. forced landing down wind est. ground speed of 50 mph landed 45 deg to the rowed up corn field. Gear survived ok but sure did a lot of hammering when i was hittin them rows.

[Sam Buchanan]

John, I hope what I'm about to write is taken in the spirit of encouragement that I intend....

The key to not damaging gear legs on an Eagle is to know how to land the plane. The lightly-built Eagles are intolerant of poor airmanship, but will reward the competent pilot with a long, uneventful service life. Assure your skills are at the point where you can land a plane and not merely arrive (semi-crash) and you won't have problems with the gear as designed.

If you fly the plane over-gross, and many do, the gear will need to be beefed up, sooner or later...

I can see how the LE could be easily flown over gross, but an XL flown over 575 lbs is a very heavy Eagle/pilot!

I consider the Black Max tires with solid struts to have equivalent shock absorption to the sprung struts with cycle tires. The low pressure tires absorb a lot of energy. I run a max of 10 psi in the Carlisle tires, and flew an entire summer with nearly no pressure. The sidewalls were stiff enough to support the plane but it did wear the outside edges of the tread.

[Sparrow]

Thank you for the information.
 
Tom, I can visualize what you told me about the axle causing a bending moment.  I am fairly sure I have seen your previous posts showing 2 or 3 pictures of the Eagle leaning onto its starboard side and then a picture of the repair.  That may or may not have been you.  I have been scouring the Yahoo site and saving information from there because I am concerned the information base will be lost over time.
 
Weasel that would have been a great video on how to use an Eagle to cut fodder.  I suspect the heart rate was in the fight or flight mode by the time the machine came to a halt.  I am pleased to hear the gear held together.
 
Based on the picture I am developing the damage is more akin to an impact load, due to the bottoming of the spring assembly and coupled with a bending action by the wheel being torsioned around.  If both of these loads are simultaneously present the probability of a bent gear goes high.  So it isn't a pure compressive load leading to a buckling action.  It is a compressive load coupled with the torsioning action of the axle as the wheel is twisted backward and upward. 
 
All of this information is very good.  I thank all of you for taking the time to share.
 
Sparrow
 
Tom & Weasel, do you remember applying the brake?  Breaking action will add to the torsion from the wheel hub to the axle.

[rockiedog2]

A sure fire way to bend the gear is to drop it in on one wheel in a bank. That compression load bends the front leg up behind the front lift strut. Like an elbow. I think this is probably the most common reason the gear gets bent. If we fly it on with a little power on the mains instead of full stall 3 point land it this won't be as apt to happen.

Another sure fire way to bend it is to crash it backwards and sideways. In this case the stupid pilot ran it outa gas. The hubs broke outa both bike wheels from the rather nasty sideload. And the left gear leg bent in what looked to me like an illogical way. Never did quite figure that out but didnt spend much time pondering, maybe 3 seconds. The right gear wasn't damaged.  Notice in the pics that the gear had already been repaired with a 7/8 x035 sleeve over the 3/4 049 tube that was bent from the drop it in on one wheel in a bank. I didnt do that one. Jerry did that. The 7/8 tube didnt bend much. Anyway the typical gear leg repair takes about an hour to cutout and sleeve. Not a very big deal usually. I like the bike wheels...theyre light tough and cheap and absorb a lot of energy not only in the above described crash but in normal everyday landings and sideloads. And I think low drag. And the bike brakes will stand it on the nose on pavement and slide the wheels on grass.
You got some good options on the wheels and brakes...bike and black max. 3/4x 049 front gear tubes are good especially for off airport landings. 7/8x035 is lighter than 3/4x049 and wud be much stouter if youre gonna abuse it. If I had decided on 3/4 for my mission I wud abandon that and go with the 7/8x035 for less weight and stiffer. That way you will crunch the fuse instead of the gear.  Maybe not so good after all. Choices choices...
Have fun
Spencer

[rockiedog2]

while we're talking about the gear and since all our past treasure trove of info is over on the other site here's some on the tailwheel which takes the worst beating on anything on the plane (unless you're doing nosestands and then its the prop). heres some pics from a while back. This tailwheel spring and pivot have held up for me whereas about a half dozen before it haven't. It's light simple and cheap
Joe

[Sparrow]

Hi Joe,
 
I love it.  Man the LE aint no combine and I think Weasel said he went into a corn field that had been cut already.  That bird looked like it belly flopped in and tried to use the prop as a blender.  Holy crap, the bird is tougher than nails.  You sure wouldn’t get away with this least amount of damage in a Mini-Max or too may of the other competitor aircraft flying today.  Leonard sure knows how to design a tough bird.
 
I can now see why the gear loves to bend like an elbow when hitting the ground.  Your explanation is great and it sheds light on what forces are impacting the various gear members and constantly bending them in similar ways.
 
I am glad you included the tail wheel along with this.  I like your design and I know I can maybe do that too.  It looks light weight, basic straight forward solution to a problem and durable as a nagging wife.  I don’t have one of those but I have heard that to be so.
 
I have spent a lot of time over at the Yahoo site and I am still learning how to slide around over there. I am concerned about losing all the information contained there.  It truly is a treasure trove of good information that supports the reasons for the changes that have occurred over the years.
 
So Joe, you would go with the 20” Murray wheels and disc brakes over the Black Max wheels?  The people at Black Max said the guestimated weight of the system is around 13 pounds total.  I am figuring on 14 pounds and that would be what I would use in comparison.  I don’t remember any weight expressed on the bike wheels with brakes.  Does anyone have a feel for what that might be?
 
I thank all of you for all this great information.  I am fairly sure regarding the tail wheel direction but I am still in a deciding mode on the mains.
 
Joe, is that tar an all terrain tread or a snow tread?     Joe, is the spring a cut down leaf spring from the junk yard?
 
Thanks,
 
John

[Jlwright]

I consider the Black Max tires with solid struts to have equivalent shock absorption to the sprung struts with cycle tires. The low pressure tires absorb a lot of energy. I run a max of 10 psi in the Carlisle tires, and flew an entire summer with nearly no pressure. The sidewalls were stiff enough to support the plane but it did wear the outside edges of the tread.

Sam, I plan on landing mostly on grass strips around where I live and wondered how much you land on grass. Coming from an RV-9A that doesn't tolerate rough fields I sure don't want to stand the XL on its nose. I really like your setup but concerned about the small diameter of the tires verses the bike wheels.