Lately, I've found myself admiring the design of the Meyers 200. One of the interesting aspects of its construction is that a large portion of the structural airframe is steel tube/truss, covered by an aluminum skin. The airframe as I am led to believe has also never been subject to an AD.

Does anyone know how the issue of galvanic corrosion between the steel tube/truss structure and aluminum skin was overcome? I am very curious how the designers attached the aluminum skin to the steel.

Mooney is the same from the baggage area forward.

Ditto Piper Apache/Aztec.

For that matter, a great number of Biplane designs have metal over steel tube from the cockpit forward.

FIFY!
The redesigned Ultra series Mooney’s replaced the aluminum sheet with a carbon composite shell over the steel tube frame. The strength running through the frame is what made it possible to add a pilot’s door to the latest Mooneys.
I hope they don’t turn out to be the last Mooneys, but it sure looks that way.

Edited to correct autocorrect

Thanks guys, seems like the aluminum (or carbon fiber) over steel is a more widespread construction method than I realized.

I'm still curious how the fastening works and what was/is done to mitigate galvanic corrosion between the dissimilar metals (specifically in the case of the steel/aluminum interface).

I don't know the specifics with the Meyers or others, but 2024T3 aluminum and mild steel are not that far apart on the galvanic charts (see AC 43-4B Table 4-1).

Carbon Fiber is far away from either, but the aircraft I am familiar with that have a lot of carbon structure all have insulation barriers, for example insulating strips on carbon floorboards in corporate jets.

Oh Ed - quit reading and tell us about your Myers .....

I fly on occasion a friends Commander 200D/Meyers 200. Very solid feeling and flying plane. From what I have seen other than primer there are no special galvanic precautions taken. From looking up in the wheel wells and in the baggage compartment area it would appear that corrosion issues are not an issue. There are steel tabs/strips welded to the tubular frame that are drilled and the Al is riveted to them.

The plane is a 1966 model and looks and is very nice. The owner is a older gentleman, former AF and airline pilot who is, by his own admission, reaching the end of his desire and abilities to be a GA pilot. I fly with him, not required, but we enjoy the flights to run the engine and back each other up on local flights. I am on his insurance and have taken the plane on a few long X-countries. Fuel flow and speeds are Bonanza-like.

The plane is for sale, last I heard.

We looked at a couple, and may have purchased a Meyers before we bought the Bo. The determining factor was, we wanted a good autopilot, and options are limited on a Meyers. But I agree, they are great airplanes.

Dave, here's a thread from MooneySpace where they had to repair some corrosion caused by mice. If you look carefully at the pics, you can see where they attach some aluminum angles and such and directly to the steel tubes, and then rivet to the angles. Where the aluminum skin is curved, they use formers.

https://mooneyspace.com/topic/19403-corrosion-repair/

@Don Tedrow:

Thanks for the info on the Mooney. I checked out those pictures and yes I can see some of the attachments you were talking about. Very interesting that a lot of bolts and rivets extend into the steel tubes (from appearances at least). Also very interesting to see aluminum structure in direct attachment to steel structure.

Does anyone know (or have pictures) to how Meyers did it?

The dissimilar metal does not seem to be a big issue but I have had trouble with a couple Piper Apaches.

The Apache has a steel tube frame inside the fuselage from the baggage aft wall forward to the nose gear. The floor is aluminum panels held to the truss with screws and tinnerman nuts.

Piper painted the tubing and in some cases glued a cotton woven tape to the surface of the tube that will contact the floor.

The floor is insulated with a plastic sheet coated fiberglass insulation which is sandwiched between the floor and the tubing.

When I pull up the floors during major airframe work I found serious tubing damage from corrosion. The rest of the airplane looked fine and the lower visible parts of the floor tubing looked ok through the belly panels. The damage was only visible when the floor and entire interior was completely removed and only on the section of the tubes in contact with the floor. The cotton tape had come loose in many areas and was hanging down. The plastic covering the insulation had worn the paint off the top of all the tubes

To fix I had to drill a small hole near the damage to find the tubing wall thickness, split new tubing in half and weld the split sections on top of the majority of the cross floor tubes. It was not feasible to remove complete tubes except for two in the baggage area because there was no way to get the TIG torch in to the cluster joints at the longerons. Piper sprayed a sound deadening material similar to auto undercoat on the skin panels and it’s very possible to catch it on fire. Painting the tubes is not easy with only access from one side. If there was damage near the cabin walls or on the longerons it would be impossible to fix without unskinning the airplane.

Luckily most Meyers should have been hangared which will help but it might be worth a try to lift a section of the floor even slightly if possible and look at the tubing it contacts.

In the case of corrosion forming on the outside of the tubes you may not have any access between the tubes and the skin to repair or repaint the tubing. Try to get any look you can. If it’s been indoors it will probably be fine but worth a look to be sure before purchase.

I think there was a 200 for sale at Albert Lea MN last time I stopped in. Looks like a fun airplane.

[quote="Dave Koziel"]Lately, I've found myself admiring the design of the Meyers 200. One of the interesting aspects of its construction is that a large portion of the structural airframe is steel tube/truss, covered by an aluminum skin. The airframe as I am led to believe has also never been subject to an AD.

Dave there never has been a true AD against the airframe of the Meyers. The construction you are speaking about is the fact the entire canopy/cockpit area and center section is crafted from 4130 Chromoly tubing, not just 'standard tubing' like many other aircraft. It essentially provided a roll cage for the pilot and pax. It's a very overbuilt aircraft, but our 200B model trues out at about 190kts cruise at 7k MSL. Enjoy!

Awesome sled!

I looked at a 200 before buying the V35B. I liked the speed and the no-AD thing was nice. It come at a cost though. The useful load was atrocious. Less than 1,000lbs due to the robust construction. The Bonanza, if I recall correctly, was around 1,100 and I could have added VGs for another 100.

The panel seemed hacked together. Not bad, cheap, or ugly but switchology and aesthetics were clearly not a priority. That wouldn't stop me from buying one though.

Cool plane though. I really had to look at my wants vs needs list to convince myself not to buy it.

Yes, no doubt the useful load could have been improved.... Plane was overbuilt. Our useful load is 939, but hoping that increases when we upgrade the panel. My great-grandfather started Meyers aircraft with Al Meyers back in the mid 30's, so I am fortunate my grandfather worked there and is able to help with rigging, parts, etc. Just aren't a lot out there, so can be tricky to maintain!