HOw to bend the gear


18 posts in this topic

Posted

I had this plane sold and just wanted to do one last flight..The forecast was for calm winds and when I showed up at the airport it was calm. I have the coil spring "Hatz" type shocks which bottomed out and bent the left gear. YOu can see in the video towards the end if you look down at teh left gear leg it is bent from my hard landing....

I went out and flew around for about 20 minutes instead of just around the pattern.. when I came back the (1)wind had picked up to about 20 mph from the right direct cross wind.

(2) I had installed one size smaller idle jets to smooth out the idle just a little and it idle smooth at 2200 on the ground. I forgot that in the air, the prop unloads so I could not get the engine to come below 3300 in the air on landing. This was a surprise to me.. So on the first landing attempt I landed long and the plane just didnt want to slow down so I went around for worry about running off the end of the runway...I guess I should have shut the engine off but it all happend so fast I dont think that fast...(3) on the second attempt to land I let the wind blow me across the runway on downwind leg and yet I continued to salvage the landing,....I didnt know what was going on with the throttle, thoughts of the housing slipping off or the engine goign to idle by  itself crossed my mind so I was determined to LAND.(4) my airspeed is a POS and hard to read. If you look, you will see the airspeed get dangerously slow as I get close to the ground... The airspeed bleeds off rapidly from 45-35mph and I knew this but I was trying to slip and towards the end do a skidding turn to line up with the runway....I ended up stalling out about 5 ft in the air and hit hard, hard enough to bottom the coil sping on the left gear and bend the gear leg. The the wind turned me to the right  and onto the ditch... I have 6.00-6 tires so they do not soak up much landing shock. If I had tundra tires I might have not hurt anything...

I know the key is a stablized approach and I did not do that... I should have gone around again and gone out farther and set up a longer final approach and a stablized approach...I just got behind the plane because they are quicker than most spam can planes and even pipers...we all flew at one time. being light weight they have low inertia so you have to pay attention to speed reduction, they happen quick.

I fixed the tail and the left wing tip and ordered the parts to fix the gear leg then just sold the plane.....38 yrs of flying and 3300 hours never bent a plane till this... but I look at the video and I see all the mistakes I made.....hopefully it will help others not do the same..

 

Oh , one last confession... my brakes are crap, I orderd new pads but they had not shown up when I flew it and I also have that damn Maule tailwheel and I felt it "Pop" as the ground loop started and the tail took a good side load the tailwheel "released"... POS, anyway... dont think much of them.... there are posts on this site on how to remove the cam so they dont unlock...

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Posted

When I went off the runway, it was so violent, my head smacked the left door and my camera which was clipped to my cap, flew off in the grass..... nice touch...!!!

The smack was for being a dumbasss!!

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Posted

We all have had our ass handed to us out there buddy...  Hell I, as a new TW student, ground looped twice in one day!  (No better way to learn than THAT!!)

Thanks for posting.  This is a great reminder for everybody to review and think through.

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Posted

damnit.. that little smack down should not have bent the gear... Chalk up another one to the shitty design of the spring gear not allowing enough travel before it all goes metal to metal.  I truly hope after all the preaching that has been done on here and the relatively easy fixes that have been posted (I fixed my problem in less than a day) that we don't have to ready any more of these stories of birds being bent by a very well known and documented problem. 

Sucks that it happened to ya but glad you walked away from it and the bird will live to fly another day!

:BC:

 

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Posted (edited)

When I went off the runway, it was so violent, my head smacked the left door and my camera which was clipped to my cap, flew off in the grass..... nice touch...!!!

The smack was for being a dumbasss!!

Damit man!  I'm sorry and relieved you didn't get seriously injured.  I'm waiting for mine still -:(   In the meanwhile, I wear a flight helmet and keep that cam uninstalled on the Maule - always when flying.  If and when I get smacked for being a dumbass, I hope to walk away from it w/out head trauma so I can at the least, try again and be better at it or die another day.  Thanks for sharing for the benefit of everyone.

Edited by allonsye

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Posted

Mayb a support welded between front and rear leg help put some strengh in it? And a step to boot if u dont cover them. Seams like long run for the legs without something.  And is the tube running from left to right on front of gear right under fuse little bent also? 

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Posted

Mayb a support welded between front and rear leg help put some strengh in it? And a step to boot if u dont cover them. Seams like long run for the legs without something.  And is the tube running from left to right on front of gear right under fuse little bent also? 

You hit on something Buck.  There's probably an engineering (not my forte at all) equation that could be applied here.  It really is a matter of managing energy.

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Posted

WOW! Thanks for posting, Sorry for the damage but you walked away.

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Posted

Mayb a support welded between front and rear leg help put some strengh in it? And a step to boot if u dont cover them. Seams like long run for the legs without something.  And is the tube running from left to right on front of gear right under fuse little bent also? 

putting a brace front to back does not do anything to keep it from bending inwards.  The issue is the geometry and the spring bottoming out too easy and things going metal to metal.  Its been beat to death and engineered from hell to high water. 

:BC:

 

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Posted

Well just wondering. Seams that would help, cause as one bends and not the other bends the distance becomes more from front to rear leg, not saying its the cure just may help give strengh, i c even stock gear with a brace sometimes, so if she bottomed out and bent gear does it look like the left gear bent, pulled the center thro the spring mayb pulled right longeron towards the left and bent the support tube also that goes from left to right? The one right under the fuseloge? Or is that tube made that way? 

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Posted

your right on how this design bends the gear and fuse.  with the direct pull from side to side it does not distribute the load.  Again, this has been beat to death on other "gear threads" and a quick search on gear design will give you more reading and engineering than you can shake a stick at.  Sure, you can beef something up to the point it wont fail, but that will just transfer the shock loads to another part of the airframe and do even more damage.  Putting lipstick on a pig does not make said pig a good date.. Without changing the design of the cabane vee and dropping the center point down your still putting way too much stress on the fuse and will be bending legs and fuse sides.

:BC:

 

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Posted

AS much as this has been discussed and beat on around here it kills me to see another bird bent up due to a well known and well documented design fault.  It seems the "it hasn't happened to me yet so it must be good" mentality can only be overcome by bent birds.

:BC:

 

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Posted

You guys ever notice its always the drivers side getting bent. Good chance there all flying in with the nose of the bird a little off to the right.

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Posted

I've mentioned this before, and can't remember that I got a real good reason why it wouldn't help.  Why not tie the center of the cabane to the seat truss?  If the cabane can't go down, it can't pull in on the sides.  At least that's how I'm seeing it.   Take it one step further, and if your seat truss is already infilled with steel to stiffen it up, why not connect right to it with a couple of tabs and eliminate the cabane all together?  That's what the bungees pull down on in the standard gear, and if the truss is infilled, it will take a lot of stress.  Shoot me down, but please give me a good reason when you do it?  This doesn't really address the bending of the gear on this particular Kitfox, but it's related to the entire design.  JImChuk

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Posted

I had 6:00x6 tires installed. They dont asorb much shock. Larger softer tires would take a lot of shock. It was a fair smak down landing but I have hit a lot harder in my Ridge runner with bungee gear and never bent anything..

The problem is the shock strut with the spring and slot can only travel about 2.5" and then bottom out , metal to metal and something is going to bend...

If I had tundra tires installed, this probably would not have happened....the gear getting bent!!!

I did weld in the tube from left to right across the top of the "V" cabane so that probably saved the fuselage fittings from getting bent...

Either enlong the slots in the shock struts and install stiffer springs or (2) install a shock strut with bungees like a J-3.

 

If you look close at the video, right AFTER I smaked down, you can see the left gear leg, at least part of it and it is bent so the hard landing bottomed the springs and the gear leg bent.... THEN I went I went ditch crusin!!!

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Posted

DAYUM! Think you for giving me more reasons to have sleepless nights! Very good to read that you were not hurt (other than aybe some pride) and for once again reinforcing the lessons my CFI kept pounding into my head, “Stabilized approach”....”STABILIZED approach”....dang it Columbus, “STABILIZED APPROACH”

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Posted

Id be VERY careful flying that "hatz" type coil spring shock stut...ONe hard landing, or hit a ditch or anything to bottome the springs out and you WILL bend metal...

If a person was determined to fly this setup, get with Leni and do what he did, lengthen the slot and install stiffer springs. or

 

INstall bungee gear like a J-3 set on the shock struts

 

Or install the newer nitrogen shocks if you have the money....

I liked the wide gear, makes the plane a lot easier to handle....

large tires take up a lot of shock too

 

 

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Posted

Zadwit, how about all the broken tailwheel structure? It looks like it cracked the steel back there to sever the entire TW structure. I suspect your landing was very, very hard. Any idea of the G's on impact?

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