Hi Gang!

It’s been a long time coming, but worth every bit of the effort.

As many of you know, I brought N9683U into FletchAir Fleet Support (TS36) in November of 2015 for it s annual nothing major, just an annual right? Read on.

To recap: I flew N9683U into the shop from LaPorte, TX (about 218nm) and she flew great, smooth operation, nice WX, and all was right with the world. My buddy who would fly me back in an Archer II left at the exact same time and I beat him to FletchAir by about 5 minutes (and he had 180hp!) Woo Hoo! Cheetah wins again!

Anyhoo, a few days after David and his awesome mechanics have went over her with a fine-toothed comb, a list of ~67 squawks was emailed back to me, most were deferrable but FletchAir really wanted me to know every single thing they found out of the ordinary. Just a few minor issues, like low compressions, missing half a cam lobe (since the rocker arms could be wiggled in-place), lifter spalling, severely corroded main spar, failed wobble test on 3 cylinders, firewall corrosion, leaking exhaust clamps nothing major right? And to think I had been flying my kids and grandkids on long cross-countries! Sometimes it s the things you Don t Know that help you keep your sanity. To add to the scary factor, this same aircraft had been used at a flight school at KDWH for primary instruction and supposedly maintained by skilled mechanics. The previous annual was relatively minor, a #4 cylinder change due
to exhaust port erosion, cracked LH brake cylinder and worn canopy tracks topping the list nothing major right? Being leery about such a minor annual played into my decision to bring it to a guru for a thorough going-over. Boy was I glad I did.

Now I had a serious decision to make. My cat-bird wasn t leaving with an approved annual any time soon. The cost of the repairs and overhauled engine would easily exceed what I paid for her, much less what she would be worth after the fact. She was tired, well used and abused, an engine with about 1685 hours SMOH in 1995, about 3700 hours total time, seven owners who all made their own special contributions (for better or worse). In short, she had served her time, was tired and neglected and ready for the scrapyard for parts to keep the rest or our Grumman fleet alive. The cost of the spar replacement with a tired engine alone is usually enough to dissuade many owners from doing anything more.

83U had served me and my family very well in the year since I bought her and having retired in September of 2015, I owned her outright and figured I had the time and resources to keep her in the air. I knew the overhaul alone would blow my budget, much less the spar replacement but she had been a good bird overall. I asked David to continue the inspection for any other major items and get back with me. The shop had paused the squawk write-up novel at the engine issue to let me decide whether to go forward from that point or not. Luckily, no other major issues popped up although quite a few other items did (again, most were deferrable my choice). I instructed FletchAir to replace the spar and send the engine out for overhaul to Custom Airmotive in Tulsa, OK and I figure I d defer as much of the remaining non-airworthy items as possible to give my bank account a chance to rest (or leaving retirement to pay for this!). Time to pull the trigger

Spar was replaced and the engine began its trip to the overhaul shop. Before it got there, I consulted with David and decided on the ECI Titan Ceraminil cylinders, 160hp HC upgrade and the CentriLube camshaft modification STCs. I wanted to make sure that the cam was lubed as soon as the oil pressure came up. It s been said from various engine authorities that in cold weather, it might take as long as 3-4 minutes for the oil to splash up onto the cam lobes for lubrication, essentially running dry for that period of time. After having seen my half-worn camshaft and knowing how vulnerable Lycoming camshafts are subject to spalling, I didn t want to wait that long. Figuring a fresh engine should probably be monitored closely, I had a JPI EDM-830 (with all the bells and whistles, including carb temp) drop-shipped to the shop.

Knowing that my then 3-month retirement wasn t doing my health or state of mind any favors, I asked David if I could come up, stay a few weeks and help with the minor items. I m mechanically inclined and have rebuilt more than a few automotive engines in my time as well as having spent time in the Navy working on avionics subsystems and wiring. How hard could it be right? Wrong! Working on aircraft is a whole different animal than cars, woodworking or microcontrollers but those having those skills and knowing which way to turn a wrench would come in handy. After a few weeks of hanging around the shop, things were starting to click and with the help of the great mechanics and a full service manual.

With the engine removed, the firewall corrosion was cleaned and a fresh coat of primer and Imron paint applied. Same for the inside of the upper and lower cowling (white, so any leaks would be self-evident on inspection). The engine mount was also painted and the nose bowl replaced and painted, complete with the Split-Nose bowl STC I had purchased in the previous year. The dorsal fin was replaced and painted with a new unit. Since the wings were already off, I figured it would be a good time to paint and wing-walk the wing-root fairings. Aluminum instrument panel overlay was pulled out and powder-coated in a black mini-texture to prevent glare. Numerous interior metal brackets and other items were powder coated (flap switches, instrument knobs, rear seat latches, etc) and the interior trim as well as the inside of the canopy patched and painted. While not a full interior restoration, it s amazing what your existing plastic and headliner can look like when properly cleaned, the cracks are repaired and everything primed and painted. My existing upholstery would have to wait for another day since my budget was shot all to heck. Some 3M Super 90 spray adhesive and new attachment hardware would spiff it up just enough to not make a mockery of the interior paint.

While all of this was going on, I managed to score a great price on a used Edo Aire 4000C directional gyro (approved for this TC) with heading bug and AP output to replace my worn out original DG which needed a precession reset about every 30 seconds (!). My existing Davtron M800 clock was dead so I managed to locate an exact replacement for that as well. So in that went. Relocated a few instruments to make room for the EDM-830 in horizontal orientation to the upper right of the six-pack. Each step was slow and meticulous since I was under the watchful eye of A&Ps who knew how things were supposed to be properly installed in a Grumman.

Over the life of the aircraft, many things had bee added, changed or removed sometimes with little regard for properly cleaning her up. For examples, old cabling for long-extinct avionics that went nowhere, master and starter solenoids that had been installed in the incorrect orientation, minor stuff like that adds up over the life of a 40 year old aircraft. It seems like I must have vacuumed at least 2 lbs of ancient dust from every nook and cranny. The EDM-830 would replace the defunct and inaccurate OAT gauge so there is a free 2.25 knockout available. Same goes for the inaccurate (and mostly useless) EGT gauge. The big, heavy non-op Argus 5000CE moving map display was also yanked since the old (but operational) Garmin GX-50 with coupled Century I steering was working fine. My backup is my trusty yoke-mounted Garmin GPSMAP 695 I take everywhere.

The engine arrived and the rocker arm covers powder coated in a translucent blue and laser engraved with Grumman Cheetah and the familiar Leaping Cheetah graphic. Push-rod tubes were powder coated in the same blue but I went a little different and did the intake tubes in translucent red which stands out a bit. Engine was installed with an aluminum spacer instead of the heavy stock steel unit after having been dyno-tested at Custom Airmotive. It puts out 161.4hp at 2700rpm but the shop said they wouldn t charge for the extra 1.4hp ;^)

More recently the wings were attached and leak-tested (no leaks! Woo hoo!), wiring cleaned up, EDM-830 probes installed and tested and about a gazillion other things that always seem to be on the To-Do list. Fairings and access panels buttoned up and finally, nothing airworthy left to fix. It s time. Finally, it s time.

Initial engine start went great and all systems operational and after a short run to warm things up, back to the shop to inspect everything. A few minor leaks from the rocker arm covers was quickly fixed and some wire ties that needed to be snipped. It s time for the first full run up and test flight around the pattern! Following my 8-page test-flight checklist took a bit of time with those items not directly related with the engine running handled before engine start to keep the ground time at a minimum. Everything checks out and with a smooth application of the throttle I m pleased to be pushed back in my seat and the Leaping Cheetah does what she wants to do go flying! I m light on this flight with minimum fuel and a cool day so climbout was 1100fpm at 90kts to keep the CHTs under control on a new engine. No alarms, bells or other whistles that would indicate anything out of the ordinary so after 30 minutes in the pattern, landed to check everything over (again) and absolutely nothing out of the ordinary! A perfect flight!

After a successful test flight, it was a short hop over to T82 (Fredericksburg/Gillespi Country) to fully fuel the tanks for the 2 hour trip back to Houston. During the fuel stop everything was checked and rechecked yet again with no squawks noted. After letting the engine cool, it was time for N9683U to head back home for the two-hour flight. A late afternoon, west Texas VFR flight eastbound at 7500 is a wonderful thing, especially with a restored HC Cheetah that seems to want to make me very happy with all of the work that went into her. After a perfectly smooth uneventful flight back to T41, I shut her down, did another inspection and said goodnight and thank you. She seemed happy to be back home and the way she looked in the dying sunlight last night is a memory I ll have for a very long time.

Epilogue This project was a tremendous amount of work, expense, 19-hour days, heartache, cuts, scrapes, bruises and elation all rolled into one. Was it worth it from a purely practical and monetary standpoint? Maybe not for most, but for me it was important to keep one of our fleet flying and going for many years to come, whether I am at the controls or my student-pilot son and daughter (or their grandkids when my flying days are over). N9683U has become a well-cared for member of our family and seems to be very happy with the missions we have. I think she smiles when there s laughter and awe in the cockpit. She ll be around and in great shape to fly Young Eagles and ChallengeAir participants for years to come.

For me, the return on investment is beyond calculation. While a great deal of expense has been put into her, the knowledge I gained from inspecting her every nook and cranny, the people I have met (many of you gangsters!), the friends I’ve made, the experience gained as a student A&P mechanic and the sheer joy of seeing a tired, unloved Cheetah back in the air was worth it all. I’ve loved the Grumman line since learning to fly in the mid 80s and have found the people who share interest in our type aircraft to be a distinct cut above your Cessna & Piper drivers. I’ve found my second career after retirement, helping around the shop, earning my A&P ticket, and to keep our type flying and giving test-flight results back to the owners. I ll continue to be at FletchAir Fleet Support for some time and hope to see you Gangsters when you get a chance to stop by. It s been a project of a lifetime and one I wouldn’t have missed it for the world.

Tracy Norris
AA5A N9683U