Landing Gear Oleo Strut - No Bounce

Post-War Aeronca Champ airplanes
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jkvincent
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Landing Gear Oleo Strut - No Bounce

Post by jkvincent » Sat Apr 07, 2007 19:18

Here's a couple of drawings that I combined and "cleaned-up" a bit and a photo of No Bounce parts, hopefully
it might help someone when it's their turn at rebuilding.
I fabricated a wing/strut support as advertized at "Hangar9 works", it's working great, I've been able to do it all "Solo",
I jacked up the axle about 8" or so (just high enough to get the support under the wing strut and then lowered slowly.
As a safety back-up I also used my engine hoist with straps at the engine mount/firewall. Also, make certain
the other wheel is well chocked. I also plan on using the John Deere "Hy-Gard" hyd oil
(also commented on and recomended at "Hangar9 works".

I do have several questions referencing the photo,
A, (low priority) What's the significance of the red & blue dots,
B, What's this...it's not on the drawing
C, How do you identify a "regular" Taxi Spring (item 4) part # 2-953
-vs- High Energy Taxi Spring # 2-1655

also, as you can see in the photo, this cylinder had been repaired at some point, .....anybody have a good used
No Bounce cylinder For Sale? Jim

Image

Image

alaskachamp
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Post by alaskachamp » Sat Apr 07, 2007 20:06

Hey Jim,
Is item (B) a spacer(solid) or bushing(tubing), hard to tell from photo angle. If it is solid ,it could be a spacer for a weak or compressed spring??? It is interesting to see a breakdown of a "no bounce". Looks to be a alot more sturdy than the standard oleo.

jkvincent
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Post by jkvincent » Sun Apr 08, 2007 07:53

Hello Alaska, ...it's a solid chunk of alum., no holes no nothing, ...who knows??? the spring itself is very hefty,
it's only 3" long and the coil thickness is 3/8"

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Nathan K. Hammond
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Post by Nathan K. Hammond » Sun Apr 08, 2007 13:47

Jim, Great pics! Thanks for sharing those with us. Wish I knew what the dots were for, or why that hunk of Aluminum was in there. To be honest, I've never seen the inside of a 'no-bounce' gear before, so I'm at a loss as well.

nkh
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joea
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Post by joea » Sun Apr 08, 2007 20:07

More and more am wondering if its a "spacer" that someone made up out in the field???

Paul Agaliotis
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Post by Paul Agaliotis » Mon Apr 09, 2007 00:18

The colors on the O ring are for composition and usage. The spacer is a field addition so the plane doesn,t look squaty. The spring shown is a standard spring. The High Energy spring is made from Belville washers stacked on a center wire.
Paul
Mailing Adress : Paul Agaliotis 2060 E. San Martin, San Martin,Calif. 95046

jkvincent
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Post by jkvincent » Mon Apr 09, 2007 01:40

"The spacer is a field addition so the plane doesn't look squaty"

Hello Paul, fantastic....some info., but I'm still a bit confused, judging by the "build" of these stout monsters (3" long and the coil thickness is 3/8") and the weight of the a/c, it's hard to believe they would move at all.
also, if the plane "lands on the oil" and "taxis on the spring", I'm assuming that's the main spring (above the cylinder).
I'm at a loss...?? Is this (lower) spring under tension sitting on the ramp? thanks again, Jim
PS: I'm not even going to try an visualize the High Energy Spring. :shock:

MikeB
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Post by MikeB » Mon Apr 09, 2007 08:50

Great pictures and kind of interesting that you show the spacer as Paul describes it. I took the "no bouncers' apart in my L16 project to look at it and decide what needed to be replaced. Apparently someone (unknown I might add) had installed Ford speedometer drive gears (that would normally go on the tail shaft of a car transmission). As least that's what they appear to me. I just set them aside for now, but Paul's explanation makes sense.

Mike Berg
"If God had intended man to fly He would have given us more money"

jkvincent
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Post by jkvincent » Mon Apr 09, 2007 16:14

"The spacer is a field addition so the plane doesn't look squaty"

I'm not sure the spacer was to prevent a squaty look.
Here's what I've learned so far, it might not be "gospel" but I've talked to several people and it's begining to make sense now.

The (upper) Oleo Strut Assy spring in a "No-Bounce" Gear is weaker that a "Standard Gear" spring so when you landed
a little hard, the "No-Bounce" spring didn't bounce you back up in the air. That was good except that when you were Taxiing,
the weaker "No-Bounce" spring was too "mushy". As a kid, remember how it felt to ride the old "three-wheeler" scooters
with the big balloon tires? Anyway, pilots didn't like the feel, that's when the factory put in the "Taxi Spring".
it sits approx 1 1/2" below the Piston/Rod assy. Sitting on the ramp this spring is not normally under tension, it wouldn't
normally come into play until you had approx 1 1/2" down travel on the Oleo assy. and that would dampen any rocking.
NOW, ...hear comes the mysterious "spacer", if you weren't happy with 1 1/2" travel before the Taxi Spring came into play,
you could put in a "spacer" (or Ford gear as in Mike's case) to reduce the amount of travel before the
Taxi Spring "did it's intended job".

is this 100% acurate? ...who knows, but it sounds good to me!
...guess I'll leave the Spacer in. Jim

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Nathan K. Hammond
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Post by Nathan K. Hammond » Tue Apr 10, 2007 00:49

Jim, sounds like a logical answer to me.

nkh
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Ron Babos
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oleo

Post by Ron Babos » Tue Apr 10, 2007 17:12

jkvincent: The upper spring is an extender more than anything. Oil cushions the sqat during landing. Oil is very important. Once on the ground most of the load is transfered to the lower taxi spring. It was designed this way(for the military) to handle crosswind take offs better than the standard oleos. The other reason for the no bounce and it's long stroke was to allow the plane to be dropped in for landing from rediculous heights if needed. It is truly amazing to experience this. With the minimal taxi travel wind is less likely to lift the wing in strong crosswind taxi conditions, but the ride basically sucks. Both oleo styles have their good and bad points. It will work with the spacer in there, but it was designed to bottom out on the knuckles as to control the lean of the plane to a minimum. That's why even new ones only have around 1 inch of travel sitting on the ramp.
Ron
Before you believe anything I say, check with two more people. If they agree, I must be right.

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Re: Landing Gear Oleo Strut - No Bounce

Post by Malcolm Rogan » Wed Nov 26, 2014 06:51

Have just got our no bounce oleos dismantled and look pretty much like the photograph posted on this thread earlier at the bottom end but would like to be sure that in contrast to the conventional oleo the no bounce should have a steel piston sealed with an o-ring - that is what we have. Concern aroused by the fact that at the top end we appear to have a spring from a conventional oleo which was under no compression despite a spacer made from a retainer sawn in half! Would like to be sure it's the only bodge we have to rectify.

Malcolm Rogan

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