Bush gear springs

[Dusty 126]

There has been a few discussions regarding springs,has anyone tried rubber donuts and washers like in a some nose gear I have seen.Any thoughts ,

[EDMO 1078]

There has been a few discussions regarding springs,has anyone tried rubber donuts and washers like in a some nose gear I have seen.Any thoughts ,

I had those on my Ercoupe on the mains, but I think they were combined with shock absorbers. I had a Kick-Ass strong Bush Gear on my Maule, made by Atlee Dodge, and it had Hydo-shocks. They make these for Pipers too.

EDMO

I would think that rubber would get very ridged in cold temperatures - almost solid - Maybe crack! - Never had my Coupe in Alaska, but there were some at Anchorage, but never saw any of them flying in the winter.

Edited 19 Jan 2015 by Ed In Missouri

[akflyer 1427]

I sent an email to Burl to see if he would develop something for us like the AOSS system for cubs.  If I was a chemical engineer I may be able to understand the polymer stuff, but I started doing research on the material used in the AOSS system and it made my head hurt.  If some one here is a chemical engineer and they wanted to come up with the proper stuff for me to pour into a can I could make the AOSS system for our planes really easy.. I just dont know the proper crosslinked super duper gee whizz polymer that Burl uses in the AOSS system.

 

[EDMO 1078]

The replacement parts for the rubber pucks on the Ercoupe was a stack of Belleville washers.

EDMO

Leni, Sorry to override your post about "CONTRIBUTIONS TO KEEP SITE GOING" and hope that everyone will send you a few bucks.

Edited 19 Jan 2015 by Ed In Missouri

[akflyer 1427]

I think Highcountry is onto the right track using the "cub style" gear with bungees.  With this, you could put 6" long slots in it and never go metal to metal unless you really really worked at it.  If you hit that hard, folding the gear is probably the least of your worries.  I do think safety cables are a good idea as many cub owners have found out.  If you break a bungee the safety cable catches you and you dont have the sickening view of the tire punching through the lift strut at the same time the prop eats the dirt and catapults you over in a not so perfect pirouette.  You don't get style points for that maneuver unless its done with no (well maybe just a touch of) blood shed.

 

Another thing to look at is the evolution of gear on the cubs.  When they first started making extended gear, they had issues buckling gear legs etc.  Atlee dodge and a few others figured out that you need to put some braces in-between those long gear legs to keep them from buckling.  Just like on the fuse, you add a brace and make cute triangles and you add a ton of strength with little weight penalty.  Personally I would rather have a gear that weighs 4 more pounds than a wad of tubing sitting on a sand bar due to a folded gear leg.

 

I will see if I can get my engineer back on it to give me the actual loads and optimize the cabane vee angle to spread the loads and not add a lot of weight.  This will also give us the needed travel info other than... hey, hold my beer, yep that looks about right, tack it.

 

I understand that these are experimental, and we can pretty much build what ever we want out of bailing wire and duct tape, but I think some of the back yard engineers (not a slam to anyone) thought they had a good idea, did not fully test it, marketed it, and cost a lot of people a lot of money on bent birds.  I would not market a "bush gear" until I had done due diligence and beat the shit out of the gear on my own airplane and I was satisfied that it was not going to cause unintended damage to a buyers airplane unless said buyer really went way above and beyond the realms of normal abuse.

 

With that said, I really love the idea of rubber "bushings" or a polymer of some sort like the AOSS suspension system.  Maybe if I get enough interest from the guys running the "bush" gear, I can go talk to burl face to face and see what he would do for us.  Its a pisser that we spend 1500 on gear, then would have to spend another 1500+ on it to make it function right and not bend our birds.

 

[FoxDB 17]

Leonard,

The Bungie is one of the most travel ideas and is well proven, the only down side is no re-bond dampening. I used a scaled down version of the Bearhawk die spring in a canister that allows more stroke than the external die spring designs and re-bond dampening. The disadvantage is the difficulty in tuning and there is a point were the spring becomes solid. I currently have it designed to 3gs before the spring goes solid. Am considering what spring or combination of springs would change this to 2gs. I really like the design of the Roberts Struts with the Fox Float and bungie or the TK Racing all air shock. The cost is high however. I may build some all bungie struts just for S & Gs.

Dave

[akflyer 1427]

I looked at the bearhawk gear, but I hate oil shocks and the way they fail in cold temps we deal with here.  of course. they dont see the abuse or cycles that we put on the snogos so they would probably work well on our planes.  I agree on the fox floats, but again, your talking $$  like 12-1500 for a pair of them.

 

As is par for the course with me, I fear I am chasing unobtainium on a cost effective gear that does what we want, but the country was founded on dreams and I am stupid enough to chase them for awhile

 

I have been reading an old thread on the supercub forum and it seems they did the same thing we are doing here trying to build a better mouse trap.  pretty much turns out that the engineers with slide rules 70 years ago were kick ass guys that pretty much got it right and Burl is the only guy that has made a bolt on cub gear suspension product that has performed to claims and is viable without mods to the fuse.

 

I am pretty certain that a few of the guys there would be hard pressed to pass a pee test with some of the ideas they came up with   I do like the discussion here and the ideas kicked back and forth.  We may hit on a combination of things that just work well and would get us the end result we are looking for in a cost effective manner.

 

I still think the best thing you can do for your landing gear is put gas in the tanks and practice practice practice!  Since I put the gear on my plane I have done things I have not done in 20 yrs.. wheel landings and setting her down gently.  I normally drag the tailwheel then chop and plop on the mains.  This wheel landings stuff feels funny now

 

[C5Engineer 1170]

Ron did the rubber donuts on his Magnum

 

http://www.avidfoxflyers.com/index.php?/topic/1515-magnums-with-airdale-bush-gear/?hl=magnum#entry10586

[Dusty 126]

The effects of cold is something I missed, we do get frost here though!

Would rubber give a measure of damping due to internal friction?

Rubber may eliminate metal to metal contact as the spring rate should theoretically

Increase as the load is applied.

The gyro guys here used to use this systym?

Maybe in search of a better mousetrap!