MooneyAcolyte

Alright, the first part is done (starboard, before finishing, see pictures). Quality-wise, I am now about 90% there (some minor cosmetic flaws in the weave on the visible side and some "dry" spots on the edges, ~1mm misalignment of the inner and outer part). Tomorrow, I'll make a fit-check on the airplane, but am not very confident. Here's what I've learned: 1.) 4 layers of 250g/m^2 for each side (inner and outer) = 8 layers total is too thick (~2-3 mm) to mimic the aluminium sheet metal part, so I have to reduce to 4 layers total 2.) Even small misalignment when bonding the inner and outer shell leads to undesirable distortions of the final part. I will make a better run with these lessons learned. It takes a bit longer, but I am confident, it is worth it.

Thanks for sharing your thoughts. I am now convinced that I underestimated the chafe-problem. So, here is my approach: the contact areas will ALL get an extra resin layer, I will clear-coat the whole part, AND I will add anti-chafe teflon tape. If all goes well, I will be able to install the carbon covers before the summer. I will report here on any galvanic corrosion problems that show up before the end of the year. In general, I am very grateful for the community discussion here, which can only help to improve the product. My next report will be on the quality of the port-side outer shell after resin infusion.

Thanks, A64pilot. I‘ve been thinking about this and there is an excellent video on the topic by the people who build the DarkArrow: Since the wheel covers are bolted on with steel bolts, all I’ll have to do is making sure no metal-carbon contact exists where the holes are drilled. That can be done by an extra layer of resin. Sent from my iPhone using Tapatalk

The resin infusion method is MUCH Better. I get a part (inner shell port) that is "good enough". I'm about 80% there quality-wise, so I will continue to try to improve. Four mistakes were made: 1.) A small leak in the vacuum bag went undetected, the peel ply had wrinkles, the first carbon layer was inconsistently glued down on the mould, loose fibres were left below the first layer. Next up: outer shell port - with lessons learned.

Good point. Version 1.0 (two glued parts) will certainly as close as possible to the original, except for the material. For a one-piece some design work and stiffness calculations will be needed. I agree that it might be easier to produce and maintain. Sent from my iPhone using Tapatalk

Thanks. There are some “dry spots” where the resin didn’t make it. That’s either a consequence of the low temperature in my workshop (-5degC), or of the wet lay-up with hoover vacuum process I used. I presume the latter, so next I’ll try resin infusion under full vacuum. Now that you mentioned it, I might try salvaging the part by flattening down the dry spots and adding resin post-factum. It’s not a structural part after all. Sent from my iPhone using Tapatalk

The first part (top) came out of the mould (bottom) - not good enough. Have to move to resin infusion.

Thanks, I‘m doing my best. Will keep everyone posted. Sent from my iPhone using Tapatalk

The two moulds for the starboard side are done, but need cleaning and finishing. Next up: moulds for the port side.

First gel coat went on the starboard cover to make the mould surface.

Making two a side is exactly the plan. I plan 4 carbon fibre layers for each "side" to get the thickness right. Then, I trim the inside and bond it - for a total of 8 layers - at exactly the same surfaces as where the original part is riveted. I still have to decide on the vacuum bagging approach (low or high vacuum). In my experience, 70 - 80% of the work is in making the moulds. Since I have to make 4 (inside, outside times left and right), that mike take a while. I have experimented with a prototype (car fuel port lid) that was very similar and that worked splendidly. I'll keep you posted.

I have started making the moulds.

I’ll try the EASA avenue first. Here in Europe, we have the freedom of “standard change” that allows us to make minor changes to certificated, non-complex (Part-M) aircraft. Any chance you can point me to the applicable FAR on material equivalency, as I seem to be unable to find it? Sent from my iPhone using Tapatalk

Thanks - these are excellent suggestions that I will take into consideration for sure. I’ll keep you posted. Sent from my iPhone using Tapatalk

I'm in the process of making replacement covers from carbon fibre as owner-produced parts as per FAA (see FAR 21.9 (a)(5)) and EASA (CS-STAN for standard changes according to 21.A.307(b)4). I'll report here on my prototypes and whether or not I get them approved by my A&P/IA (due end of February '25). Perhaps we can make a co-op effort to get enough wheel covers for everyone. I know Lasar is selling them for 1,4 k$ each here: https://lasar.com/doors/inner-main-gear-door-550060-001?rq=gear door

Interesting. I find it now back in the general PoH, but not in the one that came with my 1984 mode (S/N 24-1447).

Is it legal to fly a J-Model without the wheel covers (P/N 550091, see pic)? I would like to take them off for some repairs, but want to avoid being grounded for a long time. Any advise would be useful. Thanks in advance.

After boroscopy today, I discovered an image of Josef Stalin on my exhaust valve. Hoe is this possible? Sent from my iPhone using Tapatalk

Ripped door seal? Cabin too noisy or hissing noises? Check out my video on how to make a new door seal for less than $100:

It's fixed! Thanks to all of you helping to diagnose this fault. As it turns out, we were spot on. Indeed, the microswitch inside the pitch servo (KS179) had failed. I went to Avionik Straubing (https://www.avionik.de), who did an EXCELLENT job. They took apart the KS179 (see attached) photo, fixed the micro switch, overhauled the motor (so I get another couple of years out of it), and lubricated the mechanical part. Due to the clear diagnosis, they were able to focus on the work that was actually needed. As a consequence, the repair was still rather affordable (€1100). I flew PH-FAR back from Straubing to Rotterdam and tested the AP extensively. PERFECT! Thanks again to everyone involved. This case is another demonstration of the value of mooneyspace. Signing off on this topic - Mooney Acolyte

Latest update: I have now an appointment with the avionics shop in Straubing (near Munich) in August for repair of the pitch servo. I'll keep you posted.

After studying the correct wiring diagram sent by @Jake@BevanAviation, I am now convinced the problem is with the PITCH servo (KS-177), not with the trim servo. As you can see, the PITCH servo has the "AUTO TRIM UP SENSOR" and "AUTO TRIM DN SENSOR" lines connected. Given the symptoms, the most likely root cause is a false trim sensing. The only other option is that the flight computer (KC 295) misinterprets correct sensor input. The procedure proposed by @Jake@BevanAviation is indeed designed to distinguish the two cases. For me, the next step is to perform this procedure. I'll share my results here.

15k$ I heard, installed. Don't quote me.

Wow! That's steep. Now with @Jake@BevanAviation's help I am 90% sure it's the trim servo KS179 (P/N 65-0052-04), I will talk to the avionics shop here in Midden-Zeeland (EHMZ). They are good, but VERY busy and not too customer-oriented. I'll share my journey here.