Amorphous M7/M6 Rebuild Project

[asa]

I've decided to jump into the deep end rebuilding my new-to-me M7, making a better plane and making progress towards my A&P. Figured I'd start a thread to document the project for fun.

It's a 1984, third M7 ever produced, with 1600 original hours on airframe and engine. It's in rough condition but I got it because it's desirable - long wing, no rudder tab, IO540. It spent some years on floats in Alaska, had it's time owned by Jeremy, and then spent 20 years in a New Jersey hangar flying 1 hour per year... if that.

As I picked it up on December 28:



After I decided I wanted to rebuild it, I spotted the M6 fuselage for sale on here and thought maybe I could tie that in. The end result of Mod Kit 57 is an M6 with M7 long wings and big rudder. My proposed end result would be exactly the same, but the path to get there would be the inverse. After talking to Shirley at Maule a bit, they agreed that it should be easy to get approved, so she wrote up a new mod kit for me. So I bought the fuselage.

Fuselage in my garage after James' harrowing delivery trip from Seattle:



I fly in Alaska during the summers so that adds a bit of complexity to the situation. I've decided to get as much done on the new fuse before heading north, so when I get back I'll have a higher probability of success in a shorter timeframe. The biggest thing would of course be the fabric.

The fuselage didn't come with doors and my M7 cargo doors won't fit so I bought some used doors off ebay. As everyone knows or has heard, doors indeed take lots of time to fit. I lucked out in that the frames fit great and it's only the hinges that need work. Easy welding project.





I ran the power and ground (in case of future tail-based ADS-B or something) for the rear nav light, installed cable fairleads, elevator and rudder cables, finished fitting rear doors.



Painted vbrace, hinges, cabin steps..


That's where I'm at now. A couple more small things to do then it'll get Oratex in a couple weeks. Will try to keep this thread moderately updated. I lucked out by having a few very key people locally that make this possible, most notably Andy Young. Also, Kasey at Maules has been immensely helpful and communicative getting me what I need.

-Asa

[Old Piper]

I couldn't tell from pics listed, but don't forget to paint black the attach points for the tail struts on fusalge.
Any thoughts of mounting an internal antennas in rear fusalge? Now's the time!
Also is your covering transluscent? If so, you may want to paint the cargo box exterior behind cargo area.
Remote radios or ELT going in the back?

Keep it moving forward, it's very grattifying when done. Looks good!

Tom

[asa]

Thanks for the tips Tom. Planning on rotating the fuse around and painting the tail strut mounts and hinges black on the next set of warm days.

Don’t have any antennas to go in the tail but am mounting a plate for the ELT at the top center of fuselage, just behind the cargo area.

Fabric shouldn’t be translucent (hopefully?).

After 2 months of waiting on a estimated 1 week lead time, I got my extended gear in the mail today. Looks very well made.

[Utah-Jay]

Wow, nice gear! I like the integrated brake lines, they came that way?

[asa]

Wow, nice gear! I like the integrated brake lines, they came that way?

Yeah, what you see in that pic is what I pulled out of the box. Includes the NAS bolt kit and STC as well.

[Dkuber]

I am really curious how your oratex recover goes. Both time & material quantity. It is on my list down the road. Please keep us posted!

[maules.com]

Regarding the extended gear. It has more drag of course than unfaired stock Maule gear.
I ran some speed checks before and after building fairings for the extended gear. The difference at high cruise speeds on 8.50 tyres was 5-6mph

[asa]

Regarding the extended gear. It has more drag of course than unfaired stock Maule gear.
I ran some speed checks before and after building fairings for the extended gear. The difference at high cruise speeds on 8.50 tyres was 5-6mph

Thanks for the info! I'm planning to fair the gear with 0.020 AL or oratex. I am really doing nothing new in my project, just using what I've learned and seen from other people's work/knowledge for which I am very appreciative - the path has mostly been cleared, I just have to go down it.

Keep the tips coming and I'll hope to keep you all updated. Today I'm prepping to weld on the rear grab handles. Going to let someone more skilled than I actually do the welding though. I trust my welding to door hinges but longerons seem a bit more critical.

[asa]

Great wx on the front range this weekend so I got to fly the M7 and work on the M6 outside. Met more neighbors the 2 days I had this in the driveway than the past year I've lived here.


Finished all the incidental pre-fabric painting as well as refurbing the rear doors. Had sloshed coroseal through the tubes to stop any rust that may have been happening in there. Prepped and painted them, reassembled all the latching hardware after refurbing it. They turned out pretty well, only thing left on them is to skin them but I'll do that down the road when I make a sheet metal and plexi order.

Fabricated and installed ELT mounting shelf at the top of the fuselage. ELT will be attached to bottom of this, antenna mounted to it pointed straight down inside fuselage. After some reading I grounded the shelf to the fuselage so the whole airframe is the ground plane rather than just the small shelf. This was how my Scout was done as well. Artex 345 ELT should arrive in a couple days so I can install tray and route the remote switch and GPS interconnect harness up to the panel.



Made the mounting bracket for hydraulic parking brake installation (Maule dwg 9117E). I'll have my friend TIG it onto the fuselage when he does the rear grab handles. I have a MIG setup but welding to my fuselage is still intimidating and above my pay grade so I'll leave it to him. I ordered the valve off ebay a few weeks ago, I think it'll be a solid upgrade from the stock parking brake setup.




Also, the oratex is on it's way from Germany!

-Asa

[drak130]

Looks great! Thanks for sharing.

Tim

[asa]

Right after I posted that yesterday I got a crate from Maule with the rear fuel lines that have to be installed prior to fabric, so I installed those last night as well. They come straight with a bend and bulb at the upper end, and the fire/chafe sleeve along the length. You have to feed them down through the B pillar and bend them as you go.

Crate also contained my new lower instrument panel. Was planning to reuse the old one but there’s be so many blanked out holes I decided to splurge for a new one. Will be a completely new panel along with the upper modular panels Maule offers.

[freedom]

watch out when you install the Oratex fabric, the wing root leading edge triangle is a knife ready to pinch a hole tru, I had to rivet an aluminum angular to mitigate the sharpness. I had told and sent pics to Lars since I believe I was one of the first to apply it on Maules.

[asa]

watch out when you install the Oratex fabric, the wing root leading edge triangle is a knife ready to pinch a hole tru, I had to rivet an aluminum angular to mitigate the sharpness. I had told and sent pics to Lars since I believe I was one of the first to apply it on Maules.

Thanks for the images. I'm aware of that possible issue but I don't quite understand how that angle where it's at in your pictures mitigates the sharpness of the point? Maybe I'm misunderstanding - the potential sharp point is the rear of 'false rib' correct? Seems like that point still exists after you add that angle?

Thanks,
Asa

[Andy Young]

watch out when you install the Oratex fabric, the wing root leading edge triangle is a knife ready to pinch a hole tru, I had to rivet an aluminum angular to mitigate the sharpness. I had told and sent pics to Lars since I believe I was one of the first to apply it on Maules.

Thanks for the images. I'm aware of that possible issue but I don't quite understand how that angle where it's at in your pictures mitigates the sharpness of the point? Maybe I'm misunderstanding - the potential sharp point is the rear of 'false rib' correct? Seems like that point still exists after you add that angle?

Thanks,
Asa

I think I see what happened. Looks like Freedom wrapped over top of the false rib, instead of going under it, like the factory does. Then he cut lengthwise, to relieve strain at back corner and open up the side of the false rib area, but this then left the part below the cut short of enough material to cover the underside-of-the-false-rib-to-fuselage-side gap. The sheet metal angle fills that area. Looks like a reasonable solution, if you go the route of wanting to square off that rear corner, and open the side, similar to what the factory does.

Freedom,
I’m assuming that your experience was the one that led Lars to come up with the idea of first inserting a “belt” of material side-to-side, under both false ribs.

I went a third route, covering over the false ribs, after first rounding and smoothing the rear corners of the false ribs, and installing a layer of anti-chafe there before laying the fabric on. This actually emulated what had been done during the previous recover, which was in Ceconite.

The photos I’m including are a bit too far away to see the details well, but they’re all I have at the moment. If you zoom in on the first one, you can see how that corner looks from the outside now. I then cut holes no larger than needed to accommodate fuel lines, flap torque tubes, etc. Doing it this way prevents that rear corner of the false rib from becoming a “cave” to collect water and get rusty, as it’s completely open to the inside (second picture), so it can breathe and dry out, and the fabric runs straight down from it, so any moisture will drain instead of collecting. Also, without the normal huge opening at the forward part of the false rib, there is much less draft into that area, and less opportunity for water incursion. I have found no need to put insulation in the wing root area anymore.

Asa, I know you’ve seen all this; just adding to the historical record for the edification of others.

[asa]

Ahhh, that makes sense now, thanks Andy