Spring landing gear

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Steve D
Posts: 50
Joined: Sun Mar 05, 2017 9:50 pm
Location: Grand Republic of Texas

Spring landing gear

Post by Steve D » Thu May 04, 2017 9:16 pm

Today I put my second wing on and while it made the plane look complete, The weight also splayed out the landing gear. I have Piper cub type gear. It is splayed to the point that it looks ridiculous. We lifted up on the gear to bring the wheels back under it, but it just slid back out.

I always said that rather than fight the bungees I would install the welded gear with the concealed spring. Now I cannot find the information on it. Can y'all give me a hint as to where the information is?

Steve D
Posts: 50
Joined: Sun Mar 05, 2017 9:50 pm
Location: Grand Republic of Texas

Re: Spring landing gear

Post by Steve D » Thu May 04, 2017 9:52 pm

Right after I posted this, I rephrased my search and found a couple of sites with the information.

Any hints or tips would be appreciated.

Blue Skies,
Steve D

aviken
Posts: 9
Joined: Thu Feb 23, 2017 9:22 am

Re: Spring landing gear

Post by aviken » Thu May 04, 2017 11:15 pm

I built the spring gear on the Jeepepol, I got most of the information to build my off the William Wynne website.
He had built one for a customers Pietenpol that they were re-powering with a corvair, and the old bungee system kinda splayed out with the extra weight. He has a very interesting and informative couple of pages on the design.

herbrose
Posts: 24
Joined: Fri Mar 10, 2017 4:33 am

Re: Spring landing gear

Post by herbrose » Sun May 07, 2017 5:56 am

Good Morning Steve:

The information have here is a darn good start, but when I built mine there were a couple of things that needed to be changed structurally, for the best possible result. I have attached pictures for your use if it helps. The first thing is the mounting base the 2 inch metal band; I made mine 1/4 which proved to be an excellent base having landed mine several times already the track is perfect, and I have yet to find anything I would change. Second, I had to cut the rod end off and shorten mine about 1.25 inches after loading it with weight; this will be "a-typical" to each build do to weight varies from craft to craft. The Heim Rod End Bearings are the way to go, for it gives you ample adjustment, but nothing is forever which is why I shortened mine. The rod coming out of the spring canister was .125 wall; yes, over designed I'm sure, but it will not fail which was my goal.

Unlike your design I sought to move the center connection to the bottom of the plate steel in the center; not as a J-3 might have been. There were two thoughts here, but angulation was the goal which seems to be best served where I put it.

Somewhere in this site there are pictures of the finished plane, there you can see the alignment. As I said, the plane tracks perfectly, so I'm inclined to think it might be right.

Hope the info helps if you need any further info yell.

Herb Rose
NX709HR Bendigo Field 74N
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herbrose
Posts: 24
Joined: Fri Mar 10, 2017 4:33 am

Re: Spring landing gear

Post by herbrose » Thu May 11, 2017 4:31 am

Good Morning Fellow Piets!

Steve, I would like to update the post here on the steel landing gear I built for my plane, 709HR. Over the last few weeks I have flown and put this aircraft through its paces; the temperature on the oil and water have stabilized having changed out the 195'F thermostat for 170'F, and replacing the 50/50 mix with 100% diesel Glycol used in the Rotax. This stuff is expensive at 14/gallon, but in flight I'm now staying around 175'F on the water, and 230-235 on the oil. The Subaru has it's potential, and I intend to find out all the quirks of that power plant.

With regard to the pictures I posted here on my landing gear, one can see that I used sealed bearing axles sold and produced by Matco; the systems they use were tried and proven on my MII, so I did very little R&D on this aspect; however, I did not use sealed bearing on the MII, but rather tapered roller bearings. That idea (axles used on the Piet) has proven wrong, and today I ordered in new wheels and axles using 1.25 axles and tapered roller bearings. This will provide a much greater side-loading capability which is/was non existent in the equipment I had selected at the inception of my landing gear build. Having now flown 8.4 hours in some not so calm rotors we get off the north and south mountains the design I have built seems to be more than adequate, but those under sized axles were my nemesis.

I'm going to do some other modifications to the craft now that I have seen the preliminary product of my effort, but I am truly blown away by the power of the 150 HP this craft uses, and the very short take offs it produces.

See you all in July and no the Piet will not be there this year, for I will be coming in from Yellowstone. Keep building guys.....the darn thing is fun to fly!

Herb Rose
NX709HR Bendigo Field

Steve D
Posts: 50
Joined: Sun Mar 05, 2017 9:50 pm
Location: Grand Republic of Texas

Re: Spring landing gear

Post by Steve D » Fri May 12, 2017 11:00 pm

Herb, I am not sure I should be seen talking to you in public, what with your Pietenpol like aircraft! I mean really A rice burning engine! and an electrical system. LIGHT! WWBD?

Just to confirm, the2 inch band you mention. Is it the square section where the tires mount? I am not clear on it.

Your gear looks good and clean.

Blue Skies,
Steve D

PS you will have the good taste to not tell people we have spoken, won't you?

herbrose
Posts: 24
Joined: Fri Mar 10, 2017 4:33 am

Re: Spring landing gear

Post by herbrose » Sun May 14, 2017 5:44 am

Morning Steve!

The 2.25 square mounting plate on the axle assemblies bolts to the 3.25 square base I provided for weldment of the tubing forming my gear. Because the sealed bearing provided little to no protection for side-loading, I have removed and will install the new axles from Matco when they arrive; they have the same bolt pattern, so it's an easy fix. What I sought to do was make sure you don't repeat the mistake I did by not using the 1.25 axle with tapered roller bearings.

I was able to change out the front cockpit instruments for a "dual-system" of fuel, volts, tach, oil and water; that mod is lighter than what was there, and provides far more information.

Lucy is heavy by Pietenpol standards, but I really like the Subaru's potential, so I press on to find out all the little quirks it might have.

Herb Rose
NX709HR, Bendigo Field 74N

at7000ft
Posts: 24
Joined: Mon Mar 06, 2017 3:06 pm

Re: Spring landing gear

Post by at7000ft » Mon May 15, 2017 9:35 pm

aviken wrote:
Thu May 04, 2017 11:15 pm
I built the spring gear on the Jeepepol, I got most of the information to build my off the William Wynne website.
He had built one for a customers Pietenpol that they were re-powering with a corvair, and the old bungee system kinda splayed out with the extra weight. He has a very interesting and informative couple of pages on the design.
My cub style spring gear did the same thing (die springs were too weak). Converted to the Pietenpol internal spring design with heavier springs based on WWs excellent post:

https://flycorvair.net/2012/10/27/new-d ... a-m-4-p-m/

Worked great, plus the top and bottom each strut can rotate independently making them easier to fit/install.

RIck H

Steve D
Posts: 50
Joined: Sun Mar 05, 2017 9:50 pm
Location: Grand Republic of Texas

Re: Spring landing gear

Post by Steve D » Thu Jun 15, 2017 9:53 pm

Well, I have made the Spring in a can! It was about as described, but it took a better welder than I will ever be. I took it to a shop that does anything welding, from big oilfield rigs to old lawn mowers and golf carts. the boss said he wanted to do this job and told me that my design may fail, but his welds won't! He built it exactly as I described and made great improvements. We compressed the spring in the shop by putting the 1 inch tube in a vise, and three big old boys would pull it down while the welder tightened the vise to hold it.

I put end rod bearings (Heim) Bearings on both ends. I like the idea of adjustability. I bought them at a local hot rod shop. The 5/16th bearing on the bottom looks and feels hell bent for strong. The 1/4 inch on the upper end may be OK but I don't know the load rating. So for $20 I am going to get some end rod bearings that have a high load rating. FK or Aurora brand most likely.

Once we were finished, one set would flex just a touch if you pushed the rod back and forth, but the other felt rock solid. I think there was just a bead of slag inside pinning the spring. So today I put a chain on each end and chained them to the tow hitches between my explorer and old suburban. My grandson had it roll forward to flex the setup. It got about 1.5 inch of flex on both of them. Now both feel like they are free. You cannot compress the spring by hand and I was glad to see them move between the two trucks. I was afraid I had made a solid rod!

I wiped it off with denatured alcohol and sanded it. Then I primed it with Rustoleum Self Etching Primer. Tomorrow I will rattlecan paint it with Rustoleum automotive gloss enamel.

I have been teaching ground school at a local flight school (for pay no less!) and work has been getting in the way of getting out to the hangar to work on the Piet.

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taildrags
Posts: 277
Joined: Tue Mar 07, 2017 10:39 pm

Re: Spring landing gear

Post by taildrags » Thu Jun 15, 2017 11:21 pm

That's the Steve that I remember, alright. The only ground crew I have ever known to paint an entire Chevrolet Suburban red using only rattle cans! Okay, so maybe I'm exaggerating just a little, but I'm sure those spring struts for your airplane will be purty as can be. Can't wait to hear the results after you get them installed and put the full weight of the airplane back on them.

herbrose
Posts: 24
Joined: Fri Mar 10, 2017 4:33 am

Re: Spring landing gear

Post by herbrose » Sat Jun 17, 2017 1:01 am

Morning Steve:

Steve, after long and somewhat tedious adventure of design/change, and reviewing the great information I have from Earl Brown, I confess, the best possible solution of the spring gear would be the design of the J-3 with regard to where the spring-canister connects to the structure. I can "lighten" my craft a bit from all indications and will pursue this modification as soon as I get back from Sentimental Journey next week. As for the rest of the modifications I've done on my craft, I'm quite happy with the results of my efforts. In my case, I think it's an easy enough task to modify my existing gear-plate, on the forward end, and would hope to have it completed in the near future.

As for the adjustability of the "shock-towers", you will not be disappointed; however, don't be surprised if you don't have to readjust the length of the plunger-tube, for I had to on my build; so make your plug-ends easily removed before the final welding takes place......i.e.: tack up. While you have a little adjustment on both ends, pay strict attention to how much threaded end of the bearing is within your structure, for it can/will fail if not enough thread has been left for attachment.

Plug ahead, it's a joy to fly.

Herb Rose
Bendigo Field, 74N

at7000ft
Posts: 24
Joined: Mon Mar 06, 2017 3:06 pm

Re: Spring landing gear

Post by at7000ft » Thu Jun 22, 2017 9:16 pm

aviken wrote:
Thu May 04, 2017 11:15 pm
I built the spring gear on the Jeepepol, I got most of the information to build my off the William Wynne website.
He had built one for a customers Pietenpol that they were re-powering with a corvair, and the old bungee system kinda splayed out with the extra weight. He has a very interesting and informative couple of pages on the design.
I had the same problem, used die springs that were too small/soft on my cub style spring gear, ended up replacing the spring struts with the 'Pietenpol' type enclosed spring design detailed on William Wynne's blog. Works great.

https://flycorvair.net/2012/10/27/new-d ... a-m-4-p-m/

Original design:https://drive.google.com/file/d/0B1Y1jV ... sp=sharing
https://drive.google.com/file/d/0B1Y1jV ... sp=sharing
IMG_1054.JPG
RH

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