2012 News and Events
Unloading Prototype in Montgomery
The prototype Stewart Mustang, N51S,
arrived in Montgomery by truck in December 2011 and has been undergoing
inspection, repair, and updating. Five One Sierra was damaged on her
flight from Florida to the west coast by the previous owners in a ground
loop accident.
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Prototype Fuselage Inspection and Repair
As of mid April 2012, the inspection phase was complete and some of the damage repairs had begun. There is no hard timetable or schedule on when Five One Sierra will be back in the air. The airframe repairs are being accomplished by volunteer A&P mechanics and is being accomplished on a "time as available" basis for now. An engine build-up for the plane will begin when the airframe repairs look to be within two months of completion.
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Lil' Beautiful Doll Prepares for Ferry Flight
In January 2012, Stewart 51 Partner, LLC purchased the completed Lil' Beautiful Doll. The event marked a reunion of two key players in Stewart 51 history: Harry Stenger had headed up the crew that finished Mr. Stewart's prototype in 1994, while Eliot Cross had flown the initial test flights on that prototype for Stewart. Cross had also flown the initial 40 hours on Lil' Beautiful Doll in 1999.
Stenger and Bill Hudgens spent a week evaluating Doll, readied her for flight, and launched Cross on the two hour gear-down-and-locked ferry flight to Bartow, Florida, to Stenger's Aero Fabrication and Restoration for full evaluation and updating. Doll, having been completed in 1998, was put down for a thorough inspection which included replacement of all oil and fuel lines, flushing and inspection of the oil cooler and radiator, replacement of main landing gear components, and total tear down of the engine for inspection and overhaul as necessary.
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During the week of the 4th of July, Hudgens traveled to Kralupy in the Czech Republic and finalized arrangements to have the construction jigs and tooling shipped to Montgomery. This will put Stewart 51 Partner in better position logistically to produce sheet metal airframe parts for the plane.
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Ringo, Eric, Petr, Holger, Hudgens, and Carsten after loading the 40' container.
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The container, packed with jigs and tooling, is lifted onto the transport for its trip to a German port for transfer to an ocean going vessel. The container arrived in Montgomery on August 7th and was unloaded.
Thanks, again, to Petr and Eric and Karl and Ringo and Carsten for packing it up in Kralupy, and thanks to Carl and Gary and Mike and Sam for getting it unpacked in Montgomery. And, thanks to Danny Clements for the Lull.
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Monday, August 13th, a good day: We fired up Doll's rebuilt engine.
Hank and Harry Stenger had gotten the engine installed in the cradle last week, with Hudgens finishing up a few pre-run items over the weekend. After all the final checks were made, pre-oiling completed and filtered, servicing the coolant system with distilled water, and five gallons of fuel in the right tank, we cranked her over and fired her up. Sounded nice, and Jim Stewart himself happened to be on hand for the event. We, of course, found a few discrepencies that will be ironed out. Hank and Harry will finish up the installation, install the prop, perform some ground runs, then have Eliot Cross take her up again.
Again, it sounded nice. Jim Stewart commented that it had been ten years since he had heard that sound. Everybody was smiling.
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Doll out of the hangar looking good as a convertible.
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Though blurred by the camera, we see the first engine run with the prop reinstalled in mid September. Harry and Hank and Neil made several runs as September wound down, debugging the engine and its systems. The crew at Aero Fabrication and Restoration had to work through drive belt adjustments, oil and coolant pressure checks, instrument recalibrations, prop governor debugging, and oil cooler thermostat re-engineering. Harry is impressed with the power and thrust the engine / prop are producing so far, and is close to turning the plane over to Eliot Cross for test flights.
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Jim Czachorowski arranged for us to meet with the fellows at Yankee Castings in Enfield, Connecticut during the week of September 24th. Mark Vecchiarelli gave us the cook's tour of the facility and showed us a lot of what the crew at Yankee processes and turns out. These guys are doing work for Rolls Royce Turbine Division, Pratt & Whitney, Sikorsky, and other aerospace firms, and wouldn't allow us to photograph some of what they were doing.
We left our pattern boxes for the castings we need for PSRU's with Yankee for now, and are waiting for estimates on these components. Tim, Gray, Jim (Czach), and Mark pose here after the tour. These guys do amazing work to the highest quality achievable in casting technology.
Below, a shot of Gray and Czach studying the front case pattern box. We also delivered the pattern for more main gear wheels.
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Above, on Saturday October 13 (we make our own luck), Eliot Cross prepares for Doll's first flight since January. Cross flew two full flights, with one abort and one short pattern due to an ignition issue. The first flight was trouble free, with full gear retraction, the second takeoff attempt was aborted due to the ignition issue, the third was a short pattern due to the ignition issue, and the fourth was a full hour in the air including barrel rolls and some fun.
Cross reported that "this thing has a lot of go!" Cross and Stenger were impressed with the power and thrust the engine / prop are producing. And, to top it off, our coolant and oil temps were on the cool side. Stenger has now engineered a baffle for the air outlet to restrict airflow for the next test flights. Further flights were scheduled for the last week of October, but were rescheduled due to hurricane Sandy.
Hopefully, we'll have photos of Doll and Cross in flight for this next go round.
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After the first flights in October, Harry and Hank Stenger made a thorough check of the engine systems and components. While checking the lubrication system components, they found several pieces of bronze and traces of "Red RTV" in one of the suction screens in the engine oil sump. Further investigation and consultation led to the conclusion that this metal and the RTV were left over from the second engine rebuild, performed about four years ago, and that this metal and RTV had been trapped in the oil breather can, which is in line between the valve train and the oil tank, the metal likely a destroyed valve guide, and the RTV from sealant used in the second engine repair, given there was no damage found to any bearings or valve guides or other components in the engine, and that no RTV was used in this latest rebuild. Whew!! Harry lamented that the "snot bucket" was the ONLY component we had not thought to check and flush during our engine removal and reinstallation. We had replaced all of the oil lines, sent the oil cooler out for complete flush and rebuild, cleaned the tubes from the engine to the cooler, and filtered the oil into and out of the engine during our pre-oiling. Another lesson learned, but not without a lot of worry. At least we inadvertently confirmed that the suction screen was functional.
Further test flights are scheduled for the weekend of November 16th, weather allowing. We want to put more time on this engine in the Bartow area as we get the initial shakedown items behind us.
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Well, some days just don't go like you planned:
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Eliot did get all set and did his run up and took off for another test flight Friday morning the 16th, but came back around and landed, taxied in, and shut down. On initial climb, the oil pressure had begun to deteriorate, forcing Eliot to cut it short.
Hank and Neil began to investigate, finding more metal, looking like the same bearing or valve guide material they had found earlier that we had thought was from the previous rebuild, which led us to conclude that the engine needed to be pulled and fully inspected. Hank began the removal, and I arrived Friday evening to assist through the weekend.
By Sunday afternoon, we had removed the engine and torn it down enough to discover that the main bearings and crankshaft journals were damaged.
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Monday morning, we loaded the engine and took it back to our builder to continue the tear down. Upon removing the connecting rods, we found the culprit.
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What you are looking at above is one of the connecting rod journals with both oil passages clogged with red RTV silicone. This material, from the previous overhaul (our overhaul did not use any red RTV whatsoever) had apparently hidden within the engine or other lubrication system components during the recent cleaning and build-up, then worked loose and found its way into the oil galleries. This material worked past the main bearings, up into the galleries to the connecting rod bearings, and stopped, thus cutting flow to the components behind them, i.e., the main bearings. The connecting rod bearings and journals actually fared OK. Our builder had done the normal block and crank cleaning procedures, had, as a matter of fact, actually performed a very thorough block cleaning after his line boring and cylinder work. We don't actually know where the RTV hid during this process, but it was there.
At this point, we are going to make damn sure the block and crank and all pipes and hoses and oil cooler and reservoir and vent can and all other components are gone back through, are completely clean and free of red RTV and other contaminants, line bore the block, regrind and nitride the crank, re-hone the cylinders, clean the block again, and go back together with new bearings, with other repairs and parts as necessary. We'll then take it to another facility with a fully rigged dyno (reverse rotation capable) where we can run it for several hours before putting it back in the plane.
Our engine builder gathered new parts through December, and is waiting to get the crankshaft back from the west coast. The crank passed all specs, and is about to be heat treated rather than nitrided. Allen, our engine builder, estimates about a week to build back up. We'll then dyno and reinstall.
PSRU Update
Quick update on the Prop Speed Reduction Units: As of January 7th, we are still talking with potential providers for the rear cases and the center cases. We have nine front cases ready to go, all the prop shafts we need, driven gears, and pinion shafts/gears. The fellows at Yankee Castings are ready to go with casting the rear case (instead of billet), and we are waiting to hear from a couple of shops that can do the machining and facing on them.
We are still sold on building center cases from billet, and are going to incorporate four small changes, all of which Jim Stewart has thought through and is OK with.
We will also be getting bids on steel liners for bearing races, bids on dampener hubs and plates, and a couple of other parts. Bearings are commercially available from several sources.
I really don't want to forecast when these new PSRU's will be available, or the final price on them, as I don't have final suppliers on board or component costs nailed down yet. I'll post as we make progress.
Hope everyone has a great 2013.
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