Landing Gear Refurb

Landing Gear Refurb

Postby Charles Schefer » Tue Mar 25, 2014 12:55 am

I am very excited to share my progress refurbishing my PA-30 landing gear. It's still in progress but I think I'm on the "downhill side" of the effort as it's all coming back to together.

A year ago I put in a new Dukes transmission and motor from Comanche Gear, the Webco Teflon push-pull conduits, and Comanche Gear's wiring kits and microswitches. Cliff and his team at Heritage Aero did a great job installing all that, rigging the gear and taking care of AD 77-13-21. We didn't do AD 79-01-01 R1 at the time since it had 500+hrs to go (but we are now redoing all the gear ADs).

Fast forward to this January and my IA and I started the annual together. We've been doing a number of upgrades including Airwolf remote oil filter kits, some LED panel lighting and LED landing lights. When it came to the gear it was mechanically in great shape but aesthetically it wasn't up to standards with the rest of the plane so I decided to refurbish it.

At first I thought I'd just take it apart enough to more easily paint it in place. However, the more I got into it the more I wanted to take apart. Finally I just got to the point I knew I wouldn't be happy unless I took everything completely apart and refurbished everything.

A big influence for me was watching Matt Kurke's YouTube video of the process refurbishing his Comanche 400 landing gear. I confess I watched it more than just a few times and for a year I've pined to have my gear look like Matt's. I also saw pics of the gear wells on Bill Schnauffer's beautiful "Miss Scarlet" (Comanche Flyer Oct 2013). Then as I was getting into my gear project Cliff sent me pics of George Ahlsten's awesome PA-30 gear refurb and that just pushed me over the edge to total commitment....

We (my IA and I) pulled the gear completely apart - and I do mean completely. I separated all aluminum and steel parts. Every part was tagged and part numbered in accordance with the IPC. Every nut, bolt, washer, bushing was measured for size, thread-pitch, thickness, etc... and cataloged in a database showing where it came from. Detailed photos were taken of all parts as they came apart (thank goodness for digital photography). Left Main Gear, Right Main Gear, and Nose Gear parts were kept in separate groups and I started glass beading everything to bare metal.

I took all the Aluminum parts to Royal Aircraft Services, in Hagerstown, MD (HGR). RAS is a 145 Repair Station with fabrication and paint facilities. They fabricated new gear well liners for me and trimmed them with new rubber (by the way - don't do this... I just learned that Webco carries new liners ready for paint and I just spent much more fabricating them from scratch). Matt Kurke supplied me with a brand new never used RH Main Gear Door. My left was in fairly good shape but had a small patch at the top near the hinge. Since these doors commonly crack near the hinge and near the point where the door rod connects I had both doors reinforced with flush doublers on these points and flush riveting on the doubler where the door rod connects. They did a great job. Both doors are now stronger, look great, match, and if you didn't know otherwise you'd think they came from the factory that way. All these aluminum parts were stripped, acid etched, alodine tanked, and then primed with Dupont two-part epoxy and then top coated with Dupont Imron Matterhorn White.

I sent the side-brace studs off to Aircraft Specialties for magnaflux inspection. When the returned I took all the Steel Parts to a facility in Newport News, VA where they were stripped and cadmium plated. It's getting hard to find cadmium plating due to the stringent EPA filtration requirements involved with the cyanide-cadmium plating process. After cad plating the parts were chromated. It's the chromate that gives hardware that nice gold finish. Like the cyanide-cadmium the chromate is nasty stuff to work with. It contains a heavy dose of hexavalent chromium (aka "Chrome 6") the subject of the movie "Erin Brockovich". Finally, after cad and chromate, for any parts that are easily visible, or are brackets (basically most things besides nuts and bolts) I then had them powder-coated white over-top of the cad plating. While I like the look of the gold chromate I didn't want the gear to look too "bling bling" :)

For the gear wells themselves I spent countless days and nights, sometimes til 4am stripping them, cleaning them and prepping them for paint. It's an arduous process and there are so many "nooks and crannies" in those gear wells and it took a very long time to get all the old grease and grime out. After several weeks of diligent work they were very clean. I hired a painter to come to the hangar to help me as I thought it would be a bit difficult to fly to the plane to the paint shop with no landing gear :). We alodined the bare aluminum of the gear wells (warning: alodine also contains chrome6) and then did the same two part epoxy primer and DuPont Imron paint as was used on the individual aluminum parts.

I drove almost 700 miles in 2 days picking up all the finished parts. We now have all but a few of the parts back and should get the few remaining bits from cad plating this week. We've started reassembling the nose gear and over the coming week or two I hope we will have it all back together. We are doing things slowly, checking everything and rigging everything by the Service Manual. When it comes to torque we are using a dial torque indicator to check the nut turning torque first before torquing with a regular torque wrench. This way we get the proper final torque factoring in the resistance of the lock nuts on the bolts. In addition to the refinished parts many new parts are going in. Brake disks, linings, various hardware. A new nose gear wheel from Matt Kurke (stripping mine revealed it was too pitted to reuse). Attached are a few pics of the progress so far...

Thanks to all the ICS members that have helped me and continue to help me with this project including; Cliff Wilewski, Matt Kurke, Zach Grant, George Ahlesten and others.

- Charles

Picture of empty painted gear well:
Gear Well 1.jpg


Another of empty gear well:
Gear Well 2.jpg


All nose gear parts back from refinishing (steel and aluminum):
Nose Gear Parts.jpg


All main gear parts back from refinishing (steel and aluminum):
Main Gear Parts.jpg


Here's a lower drag link from the main gear. It's been cad plated and chromated. Then the threads and non-paint areas are masked off and white powder-coat over the rest of the part. The second low temp bake from the powder-coat does darken the gold chromate a bit.
MLG Lower Drag Link.jpg


Finally here are some of the nose gear components partly reassembled:
Nose Gear Going Back Together.jpg
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Re: Landing Gear Refurb

Postby N3322G » Tue Mar 25, 2014 3:18 am

WOW! WOW! WOW!

Very impressive and wonderful to see.
Pat

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Re: Landing Gear Refurb

Postby Charles Schefer » Tue Mar 25, 2014 12:22 pm

Thanks Pat. For me this is the fun part seeing it all come back together. The plane is 2 years older than I am and my goal is to make sure it outlasts me. The cad plate guys told me that I'll be in my grave long before the steel parts they refinished ever start to corrode :)

- Charles
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Re: Landing Gear Refurb

Postby Ed Asmus » Tue Mar 25, 2014 1:46 pm

Awesome Charles,

I was at Cliff's shop yesterday discussing the gear on my friends Comanche and we were talking about your "museum" piece. I am envious and though I know the work that Cliff is doing on my buddy's Comanche is not going to look as pretty as yours, I am confident that when he is done, mechanically we will be in good shape.

Congratulations on your accomplishment! That is a lot to be proud of!

Ed
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Re: Landing Gear Refurb

Postby Ed Asmus » Tue Mar 25, 2014 1:46 pm

Awesome Charles,

I was at Cliff's shop yesterday discussing the gear on my friends Comanche and we were talking about your "museum" piece. I am envious and though I know the work that Cliff is doing on my buddy's Comanche is not going to look as pretty as yours, I am confident that when he is done, mechanically we will be in good shape.

Congratulations on your accomplishment! That is a lot to be proud of!

Ed
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Re: Landing Gear Refurb

Postby Ed Asmus » Tue Mar 25, 2014 1:47 pm

Awesome Charles,

I was at Cliff's shop yesterday discussing the gear on my friends Comanche and we were talking about your "museum" piece. I am envious and though I know the work that Cliff is doing on my buddy's Comanche is not going to look as pretty as yours, I am confident that when he is done, mechanically we will be in good shape.

Congratulations on your accomplishment! That is a lot to be proud of!

Ed
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Re: Landing Gear Refurb

Postby Ed Asmus » Tue Mar 25, 2014 1:48 pm

Sorry for the "triple" response. Computer was being foolish!
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Re: Landing Gear Refurb

Postby Charles Schefer » Tue Mar 25, 2014 2:37 pm

No worries Ed and many thanks for the kind words. However unlike a "museum" plane ;) I do intend to fly the plane regularly. I've been in the habit of wiping the plane down top to bottom after each flight / trip but now I am going to add detailing the gear to that process. I intend to fly it regularly but also I intend to keep it detailed and clean. I am sure I won't be able to keep it perfect but in my view the only way to keep it perfect would be to not fly it and in that case what's the point? :) I suppose the ideal "museum" planes are those at the Military Aviation History Museum in VA Beach. They have an amazing collection of WWI Reproduction aircraft and authentic WWII aircraft. It is an AMAZING place. The coolest thing is that while all the aircraft are pristine they are all also flown regularly. On May 16 (my dad's birthday) we are flying down to watch as they will be flying a Spitfire Mark 9, and Hurricane, and a Lancaster bomber in formation up and down the beach. Anyway I digress... my point it that now that my gear is all clean I plan to keep it that way. Easier to stay up with it a flight at a time than go through another restoration 20 years from now.

Glad to hear you're near Cliff's shop. He did great work on my bird and I wish I was closer to RFD. When Cliff did all the work on my plane he did warn me that the paint in the gear wells was a weak spot. Actually the gear overall was a weak spot but like your friend's plane Cliff took care of all the mechanicals for me. He just told me that at some point I'd probably want to address the paint (or lack thereof) in the gear wells. It's funny because the paint on the rest of the plane was (and is) fairly outstanding IMHO. It was painted in 2008 but still looks new. I think when it was stripped and redone they just didn't bother much with the gear.

- Charles
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Re: Landing Gear Refurb

Postby N3322G » Tue Mar 25, 2014 6:34 pm

So Charles - if you are going to try to keep it this clean, are you buying stock in a q-tip company?
Pat

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Re: Landing Gear Refurb

Postby Charles Schefer » Tue Mar 25, 2014 8:41 pm

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Re: Landing Gear Refurb

Postby George Kretschmann » Thu Mar 27, 2014 3:10 am

If I had something that clean I would be afraid to fly it. Charles, you are a master craftsman with attention to detail.

George
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Re: Landing Gear Refurb

Postby Andres Darvasi » Thu Mar 27, 2014 2:24 pm

Congratulations Charles, what a wonderful work!
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Re: Landing Gear Refurb

Postby Charles Schefer » Thu Mar 27, 2014 8:41 pm

George / Andres - thank you for the kind words. George I am sure it will be easier said than done to keep it clean. I'll do my best, I probably will use a good supply of Q-Tips but I'll definitely fly it. It was made to fly... :) I'll keep it as clean as I can.

- Charles
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Re: Landing Gear Refurb

Postby Charles Schefer » Thu Mar 27, 2014 8:48 pm

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Re: Landing Gear Refurb

Postby Charles Schefer » Tue Apr 01, 2014 1:49 pm

Here are a few updated pics from the re-installation process. It's not all "roses" as Matt, Cliff and others know from my calls and emails but overall it's going quite well.

Reinstalled push-pull conduit. The "spider" mounting bracket was cad plated and then powder-coated white. The bolts that hold it to the main spar were cad plated and mounting hardware that holds the push-pull conduit in place in the "spider" were also cad plated. On the inside of the conduit that's a piece of green tape we were just using for initial alignment.
Push-Pull.JPG
LH Push-Pull Conduit and mount reinstalled


Here's the LH Side-brace stud reassembled and the housing mounted back in the gear well. The stud itself was sent to Aircraft Specialties and magnafluxed (for the 1000hr side-brace stud AD). Once I got them back they went to the refinishing facility for cad plating. The housing is aluminum so it was stripped, etched, alodined, primed, and painted. All the mounting hardware was cad plated.
Side-Brace Stud.JPG
LH Side-Brace Stud reassembled in housing and mounted in gear well


Here's a shot inside the LH gear well looking outward. The rear-side strut-trunnion mount is back in place on the rear wall of the gear well and the LH door is hanging in place. We discovered the MLG doors did not fit perfectly flush but Matt Kurke has a nice piece on his website on how to deal with this. In terms of fitment we discovered the LH door had a slightly bent hinge causing the rear of the door to close before the forward leading edge. We took the hinge apart and used a metal break to straighten the hinge and we now have both gear doors closing perfectly flush with no undue pressure. Leading and trailing edges of both doors now close simultaneously. Also in this pic you can see the inside reinforcement doubler I had put on the door along the hinge to strengthen it since this is a common crack point. I did this on my existing LH door (pictured here) and on the brand new RH door. Partly so they would match in appearance and partly so they'd both be stronger.
Gear Door.JPG
LH Gear Well looking outward with gear door mounted and rear strut housing mount reinstalled


The nose gear is more or less back in place and rigged per the process and specs of 7-12 of the service manual. Final rig to be done when all gear is assembled. Today we hope to get the main trunnions back in place.

- Charles


- Charles
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