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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PROGRESS on the PSRU!
As of February 1st, we have reached agreement with a machinist and have commissioned the casting and finishing of the rear cases for the prop speed reduction unit, and, we have reached agreement with another shop to produce the center case sections from billet. Progress has been slow, but we are pleased that we have researched these parts thoroughly and are making headway.
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Allan finished the rebuild, and Harry transported the engine to JB Racing for the dynomometer runs on Wednesday February 27th.
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Below, Jim makes the final hook-up for the ignition on Thursday, the 28th. It's about to get nerve-wracking.
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On hand to witness, supervise, and pull this off are Jack Peck, owner of Merry Mary, with 270 hours total time on his S51 and engine, Harry Stenger, aka "Fearless Leader," and the ever-cool aviator who will be strapping his carcass behind this "Wild-Ass Apparatus," Eliot Cross. Eliot is interested.
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Jim fired her off with no problems whatsoever.
After a normal warm-up and a couple of lightly loaded mid RPM periods, he took her on up.
As he got into the higher RPM / Torque power pulls, Jim had to back off and make a few adjustments to the dyno, given we were spinning reverse rotation. Dyno adjusted, he brought her on up into some actual take off RPM / Torque scenarios, some cruise power scenarios, with periodic slow downs. Data was being generated and we were looking good.
After about an hour of engine time into the program, we were on our last run for the day. The Aviator sauntered down the hall and looked out the door at the exhaust / muffler tower outside and announced that we were smoking! We went out back and, sure enough, there was white smoke boiling out of the top of the stack! Great!! Blown engine already?
The engine parameters were looking fine in the test cell: EGT's on all cylinders looked normal, oil pressure and temperature readings were fine, coolant temp and pressure were fine. What's going on? We decided to shut down as theories abounded, and, just to make it more fun, the ignition leads along the right cylinder bank caught fire! Related? Coincidental? Not a good scene.
Grasping for any hopeful explanation, some of us theorized that perhaps something was overheated in the exhaust stack, or that maybe the ignition wires being so hot had allowed smoke to be drawn into the exhaust collector tubes. Others offered that maybe we had an oil ring lined up wrong. Jim and Harry agreed that we should let the headers cool down, pull them, and see what things looked like in the ports. We did.
Everything in the exhaust ports looked FINE! No oily cylinder, no broken valve. Jim suggested we fire it back up with the headers removed.
We did.
The engine ran fine! Beautiful exhaust flames shooting straight out of the engine, no smoke, no misses, parameters looked great. No signs of any distress or damage in the powerplant.
Conclusion: Sure enough, there was enough old material in the exhaust tower that, heated with 100LL exhaust rather than the autogas that had been going through, we had basically started a "chimney fire."
As for the ignition wires, look at the photos and you'll see how close the headers were to the double set of wires. Jim's crew had twice, during the runs, tried to tie the leads away from the headers, but never could get the clearance we needed, thus the leads lighting off.
Jim plans to make another run next week with a different set of headers that will come further away from the block before turning down into the collector tubes.
As of now, looking back, we think we have a pretty good engine, but we went though some stress figuring that out.
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We really must encourage you to discourage your engine builder from using RTV or any other silicone caulk type product in building up your engine or re-sealing your PSRU. We officially declare such practice to be more than horrible.
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What you see above is Neil Butterworth displaying the squeeze-out "rope" from the excess RTV silicone a previous owner had used in building up the PSRU.
Going back: Hank and Harry had brought the engine back down to Bartow the week of March 11th and had begun to get the engine ready to reinstall. I flew down on Friday the 15th to assist / be in the way.
That Saturday, we decided we ought to borescope the PSRU just to be sure nothing was amiss inside. It had run properly, and had been thoroughly flushed, but we thought we should check anyway. As we looked inside, the gears looked fine, the bearings looked fine, but we did see evidence of RTV squeeze out, so we took the PSRU apart, and the photo above shows what we found: More of the same engine builder that screwed things up on the engine. He had apparently also resealed the PSRU, bless his heart.
We removed the silicone, cleaned the components, checked the gear lash wear and pattern, pre-lubed the bearings and gears, and used Permatex High Tack and double silk threads to put the case sections back together.
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Center case cleaned and ready to reseal.
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Center case with Permatex and double silk threads, ready to mate with front case.
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Reassembled with new fiber lock nuts.
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PSRU reinstalled on engine.
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By Sunday afternoon, the engine was back in the cradle, ready for several days of hooking up and connecting and reinstalling accessories and prelubing and the other 437 things we've done before to get this thing converted back from Hangar Queen to Flying Machine. Weather prevented me from flying back down to assist / be in the way this weekend, but Hank and Harry should fire her up this week of March 25th.
We've relearned some important lessons with this RTV problem. Again, go back to Owen Smith's manual where he discusses cleanliness and engine block prep and other practices your engine builder should follow. Allen, I am convinced, did a very thorough job cleaning the block during the first rebuild he did, such that we just don't really know where the contaminating RTV hid or came from. The PSRU, or the oil cooler, or some other component in the system? We obviously let something slip through the cracks (or, in our case, suck down through the oil galleries). You really have to go at it more than thoroughly, given possible contamination.
Please learn from our experience, and don't repeat it.
We'll keep you posted.
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The two photos above show progress as of Thursday, March 28th, where Hank has hung the prop and connected hoses and wires and accessories. We are waiting for new pulleys and belts that will update the belt drive system to the newer radius toothed system, and waiting for the return of one of the ignition systems from factory testing. Harry and Hank plan to fire her up for ground runs early the first week of April, still heading for an appearance at Sun n Fun.
As much as we want to display and share this plane with people at Sun n Fun, we are also working at making sure we do this engine reinstallation right, and fly it as necessary to be safe.
We'll continue to keep you posted.
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During the week before Sun n Fun, Harry and Hank got the engine running, checked oil filters and systems, and figured we were ready to try a flight. Eliot arrived and got one flight in that week before weather stopped the tests. The first flight revealed that the engine was running rougher than desired at full power on takeoff.
During the week of Sun n Fun, two more test flights were made troubleshooting the high power situation. Early indications seem to point to the ignition system rather than the fuel injection. Some replacement components are on order. Meanwhile, we are rebuilding the tail wheel strut and steering to improve a shimmy condition that needs to be stopped, and we've pulled the prop and governor to tie down some prop issues.
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Eliot prepares for another test flight.
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Most of April saw Doll down for troubleshooting and component repairs. We removed the tail wheel assembly to look for answers to an increasingly annoying shimmy, and found several items that needed attention. One, the condition and length of the strut spring, opened an old can of worms, and the Stewart 51 Builders Group has assisted with case histories and cures for various shimmy problems and strut spring ideas.
While having the prop and governor rechecked, we've reviewed with Hartzell the absolutely proper set up for the prop concerning counterweights, low and high pitch stops, and governor set up. We'll be summarizing that data and the communication from Hartzell after we fly again. Hartzell's Kevin Ryan has been immensely helpful in reviewing these items for us, having been involved with the earliest S51 props back in the 1990's. Hartzell keeps very thorough records and they know their business.
While up on jacks, we've gone ahead and overhauled both main gear actuator cylinders, having done the tail in March.
We anticipate being back in the air the middle of this month.
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CHECKED OUT
With updates and minor adjustments complete, Eliot flew a couple of more test flights, then had Hudgens come down for his transition into the Stewart S-51D, "Beautiful Doll." Working around showers and weather during the last week of May, Cross, from his less than oppulent aft seat, put Hudgens through the paces and signed him off for solo flight. Hudgens made his three take offs and landings on runway 9L in Bartow with Stenger watching from the golf cart. The solo flight went fine, and Doll is now back in the hangar for installation of an electric Artificial Horizon instrument for more comfortable cross country flying.
One anomoly we are still chasing is a phenomenon where the oil pressure is dropping with altitude. We've had input from several experts, most of whom say that such a drop makes sense in our installation, but we aren't convinced. Oil pressure stays within a safe range for operating, but we will be investigating this further as we continue to fly. Other S-51D builders and pilots with similar dry sump systems report that they are not seeing the same behavior in their aircraft.
We are making arrangements to have Doll at Oshkosh, AirVenture, this year. Come see us at the Replica Fighters Association site if you can make it.
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Hudgens after Three Take Offs and Landings
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Just back from Bartow after four "sorties" over the weekend (June 22nd, 23rd). All of the flights went well. Flew three on Saturday during which I climbed out and loitered over the Airport at altitudes ranging from 8,500 to 10,500 feet. These flights were intended to put more run time on the engine and systems while letting me get more familiar with operating the airplane. Performed one power off straight ahead stall and recovery in the clean configuration, and some slow flight both clean and in the landing configuration. The plane fell through straight ahead and recovered nicely. Eliot wants me to spend as much time as possible with more stall work, especially practicing accelerated stalls and recoveries, reminding me that such practice is good background for developing feel and competency in the plane. Right now, I am simply trying to get more familiar with the routine operation and stay ahead of normal flying. I do mentally think through and touch the components I'd have to go through in certain events, such as power failures or bail out situations, keeping the mental part active. More stall work on next trip down.
Sunday morning's flight was a short cross country down to Punta Gorda, where I made a low pass down Runway 15, just a conservative, safe flight down the runway at 500 AGL, no stupid airshow or buzz job, then back up and the return to Bartow. Had a better chance on that trip to look at cruise performance. Basically, at 8,500 and 7,500 feet, my groundspeed at 20" MP and 3200 RPM averaged 195 knots. Couldn't calculate a TAS because our OAT is inop. Was indicating around 170 kts. Stayed back at the 20", but still had capacity for 24" at 7,500. Fuel flow was around 20 to 21 GPH at about 100 degrees rich of peak. I'm not a big fan of running real lean, but we'll get these parameters set a little tighter as we fly more. Oil pressure, oil temperature, and coolant temperatures all behaved well. We're not sure that we don't need to get the coolant warmer: Running at about 140 degrees F right now. Had I pushed it up to 24", might have run warmer. Oil pressure stayed around 50 psi at altitude, running between 180 and 200 degrees F. Oil pressure comes back up to 60 psi at the deck, so we are pretty well losing an inch per thousand feet right now. We want to see that change and are still investigating how to control that parameter.
Basically, the airplane is doing as well as we had hoped for. We are still on track to get her to Oshkosh next month, and have plans to showcase her up there.
Other developments: Cliff Fitch is cutting the PSRU center cases this week, and Yankee castings has shipped the first production rear case section to Cliff for proof of fit. Jim Stewart and Cliff have agreed on a small change to the oil feed through the center case delivering the prop control oil, and Cliff is manufacturing that part, the steel liners for the bearings, and the various oil jets required. We'll display all the new production parts available at Oshkosh.
My youngest son, Charlie, is inventorying the airframe parts we have for the kits in Montgomery, and we'll find a way to post that inventory as soon as we can. Meanwhile, still communicating with aluminum fabricators about component production for the airframe.
I plan to be back down in Bartow in about two and a half weeks for more flights and getting ready to ferry Doll up to OSH. We'll update as things progress.
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Got back down to Bartow Tuesday July 16th and had a nice evening flight. Neal took some video with his camera phone and posted to YouTube. Neal posted three videos: S51 Flying, S51 Fly By, and S51 Landing. He did a nice job capturing what he could without a zoom lens / camera setup.
With everything looking good, I departed Bartow the next day and ferried Doll up to Pensacola. The flight went well, but we are still indicating cooler than we think we should on our coolant. Oil temp and pressure were fine. Our next move is going to be to check our temp sending unit and gage, and add another pickup / gage reading coolant in the block.
At 10,500 feet, OAT 18 C, 21.5 " MP, 3200 RPM, burning 21 GPH, IAS 175 to 180 kts: E6-B calculation came out to 215 to 220 kts TAS.
At this point, we are planning to fly her up to Oshkosh next weekend.
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My View out of the Left Wing
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This is my view out of the left wing over central Illinois on the way up to OSH at 3,000 AGL.
We had ferried Doll from Bartow to Pensacola and had done some more troubleshooting of the low coolant temperature problem. Turned out our temperature sensing and indicating was going bad on us. Harry had me replace the probe / gauge that senses coolant temperature coming out of the top of the intake manifold, and had me add an additional probe / gauge reading coolant temp in the block. This setup is working very well, and answered our coolant temp mystery. At cruise, our intake coolant discharge is running about 170 degrees F, while the coolant in the block is reading five to ten degrees cooler, which makes sense and tells us we are running the engine right where Jim Hicks wants us to. The oil temp is running 180 most of the time. I can tune these temperatures with amazing precision through small adjustments in the scoop outlet door, running fully closed most of the time at cruise, and fully open on taxi in. It is nice to finally have that wrinkle ironed out.
Flew out of Pensacola Friday July 26th to Montgomery, and pulled out of Montgomery Saturday the 27th for OSH. First stop was Evansville, Indiana. Flew that leg in right at two hours at 8,000 and 10,000. Doll flew just fine. Took on forty gallons in Evansville and studied the weather pretty closely, given ceilings on up toward OSH were in the 3,000 foot range. I had been making it a practice to stay relatively high, and not being IFR legal, I wasn't sold on continuing.
As I thought about it and called a few people up that way for first hand observations, the weather folks began to report ceilings coming up to 4,000 overcast to broken and improving, so I figured I'd go on up. The terrain was flat and cultivated, and I had great visibility, so I took on off out of EVV and cruised at 3,000 to 3,500 feet. It was an absolute blast! You could really begin to see the speed of Doll at that low an altitude, and I had safe forced landing areas the whole way up to Madison, Wisconsin, my next landing. That leg was a lot of fun.
After fueling in Madison, another forty gallons, I went on in to OSH by the Warbird Arrival, landing on Runway 27. A real neat trip all the way around, but it was COLD up there Saturday and Sunday.
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Beautiful Farmland in Southern Indiana and Illinois
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AirVenture 2013 with the Replica Fighters Association
We staged Doll with the RFA, Replica Fighters Association, guys and planes for the week. Tony Pileggi, President of RFA, helped me immensely by picking up the PSRU display from Cliff Fitch and taking it back by on his way home. That help from Tony allowed us to display the guts of the gear box that drive the prop. Many thanks, again, Tony, for that assistance.
Joe Labert, RFA Vice-President, put me up in his "Camper" trailer the first night up there, given I had no room reserved for that first night. A Luxury Camper. Real cherry wood cabinetry. Great accomodations.
Look at joining the Replica Fighters Association if you haven't already. Twenty five bucks a year gets you in the network with some good fellas who are into replica warbird aircraft. www.replicafighters.com.
Mike VadeBonCoeur, on the left, who heads up Mid West Aero, the builders of Doll, stopped by for a quick reunion and approved of our stewardship of his work.
The PSRU components on the table exhibited some of the fine parts Cliff Fitch's RotaSkipper Company, and Mark Vecchiarelli's Yankee Castings have been building for the new gear boxes.
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Below, Dave Morss fires up and taxis out for an early morning familiarization flight.
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The owner of Big Beautiful Doll was very gracious to let us pose Beautiful Doll by his Full Size North American P51-D in the Warbird area.
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On my stop back through Evansville, the Collings Foundation was on hand, displaying their B-17, B-24, and P-51B for the folks in EVV. Had a nice visit with their guys and compared notes on performance between the real P-51B and our S-51.
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Got back to Montgomery in great shape. Doll was basically flawless for the entire trip. I will say that my enthusiasm for the Stewart 51 has grown exponentially after this trip.
Many thanks again to Hank Stenger for helping me manage Doll and keeping her looking sharp throughout the week. More thanks to Stewart S51 builders Jim Czachorowski, Cliff Fitch, Neville Barrett, Bob Orre, Jan Fronk, Mike Adam, Dan Malloy, Frank Zersky, Jamon Pruitt, Rick Robinson, and Mike "Gorilla" Goransky for visiting and helping answer questions about the Stewart S51 for people. I'll bet at least 70% of the answers we proffered were correct!
As final notes on the Oshkosh trip, I'd say two things: 1) I met a bunch of great people who were very interested in seeing these kits come back on the market, which inspires me to keep pushing along. Guys like Keith Vasey, whose father operated a Jurca Mustang in the '70's put me in touch with Mark Goldberg of Bearhawk Aircraft, who is putting me in touch with the folks who fabricate parts for the RV people; both of these fellows were genuinely helpful and encouraging. 2) I genuinely enjoyed reminding people who came by and complimented Doll that the credit for Doll goes to Jim and Peggy Stewart and so many early believers in their vision who put so much into bringing the S51 into being, and Mike VadeBonCoeur and Midwest Aero for the level of craftsmanship and authentic detailing displayed in Doll.
Thank you.
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This is the view of the Barnes pump assembly from the front looking aft. You'll notice oil seeping down behind the black fuel pump drive stage down the natural aluminum oil pressure regulator stage, and oil on the other stages.
This nagging oil leak finally revealed itself well enough for me to find it after a local flight in Montgomery. I removed the pump assembly and shipped it down to Bartow, where Harry and Dr. Joe went in and replaced an oil seal and shipped it back to MGM. After reinstallation and leak check runs, we were good to go again, and have had several flights now with no leakage from this unit.
We still have one more nuisance leak at the PSRU that we'll attack when we go back into maintenance in a few weeks, but for now, Doll is running fine. Coolant temps are running about 175 to 180 from the intake manifold, ten degrees cooler in the block, and the oil temp is running about 180 to 190 indicated, which should translate to 200 to 210 in the engine.
I have logged right at 29 flight hours in Doll and am enjoying my commute from Pensacola to Montgomery and one trip to Muscle Shoals (northwest Alabama). Had a Navy T-6 Texan come up on my six and play around on this week's trip from MGM to PNS. Approach Control had let me know he was coming. He can now say he "Shot Down" a Mustang. I had to hold a heading and be a good boy. He broke off and we wing wagged each other and all was well.
Had a nice visit with the folks at Pensacola State College, courtesy of Glenn Bradley, and am beginning to study SolidWorks. Am also setting up to go ahead with improving the wing rib die blocks to produce more accurate ribs, trying to help future builders avoid some of the shimming necessary to get a really perfect wing. Our plan is to add metal to the blocks to allow us to reshape them to closer tolerances. This project will take a few months.
By mid October, still communicating up and down the state of Alabama in Doll, still running OK. Thirty five hours now. Keeping in mind that some engines have popped valves at 80, some have gone over 300. My plan now is to fly this engine to 300 and see how we are doing. Have to make the 300 first. Have a pretty detailed "To Do" list for fix-ups and maintenance when we get back down to Bartow in early November, and we'll be performing a pretty detailed 50 Hour Inspection.
Met with a gentleman from north Georgia this week (October 16th) in MGM who is building parts for another kit airplane about building ribs and other components for our kits. Still wrestling with whether to try to repair and improve the existing form blocks and find a hydroforming company, or start over with new blocks. Three fairly intelligent people have told me to start over, but I might yet trade my time to repair what we have vs. commission new ones. Not that I always make sensible decisions ..........
More to come.
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The photo above shows the pattern block for the cowling. Back to square one on finding a fabricator for the stretch form parts: I had gotten close to working out an arrangement with a stretch former in Missouri, but their press broke and they are not going to repair it. I'll be researching options again on the stretch formed parts.
The photo below shows one of the original rib pattern blocks and a finished rib. We have concluded that starting over and building new rib pattern blocks will give us the most efficient path to building ribs to closer tolerances. The existing blocks have just enough low spots and inaccuracies in them such that the finished ribs require more final shimming than we want to have in getting a smooth wing skin. Jim Stewart has coached us through improvements we can incorporate as we cut the new blocks. Nothing major, and we could have used the old blocks with some welded metal and regrind, but a clean start will be about as efficient if not more so.
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The plane is flying great through mid-November. Will be taking her down to Bartow in late November for the maintenance we discussed earlier. Doll is doing fine, and I am enjoying the heck out of flying her.
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Didn't get much flying in during November into early December due to weather and work schedule. Doll is in Montgomery waiting it out. A thorough check under the cowling revealed slight loosening of the alternator drive belt. All other components are looking good.
Getting closer to finishing our review of specs and materials for the last components we need for the Prop Speed Reduction Units. Have been getting a lot of great help and input from Jim Stewart, Parker Miller, Owen Smith, Cliff Fitch, Dick Whelen, and Bill Locher. Also had a nice visit in Montgomery with Mike "Gorilla" Goransky.
A Merry and Blessed Christmas and Happy New Year to everyone. Happy Holidays.
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The photo above shows the crank trigger wheel installation. Look closely and you'll see that the outer circumference of the wheel has begun to eat away at the pickup sensor, and if you look very closely, you'll see where the wheel has failed at the bolt slot near the center axis.
I attempted to fly Doll on Christmas Eve afternoon, but on climbout the engine began to get "bumpy." I checked gauges and leveled off at 6,500 feet, verifying gauges and setting up for level flight. I then turned off the MSD distributer ignition side and the engine went bad, verifying that the crank trigger ignition side had gone bad. I returned to MGM and landed, then drove my trip instead of flying.
That weekend, back in MGM, I removed the cowling and found that the crank trigger wheel had failed at the three bolt locations that attach it to the harmonic damper, thus allowing the damage to the sensor and the rough running. After a bit of research and listening to learned opinions, we are planning to change the cam to a smoother low end equation, replace the fluid damper with an elastomeric damper, reconfigure the pulley system more toward conventional automotive pulleys and belts to shorten the shaft extension that carries three cog belt pulleys, and fly on.
Of intense concern to us is, as others have faced, the physics of torsional vibrations and resonance. We can't fully determine whether or not this wheel failure is a problem with the wheel, or an induced failure of a good wheel due to vibration characteristics beyond the norm. The new wheel will be a solid disc without the lightening cutouts, which should help. The pulley wheel we'll use will provide better clamping and spread the pressure of the three mounting bolts better. The cam change will give us a smoother idle than what we have been experiencing. These and a few other refinements will, hopefully, keep this engine running smoother, albeit with less top end power. As I said to Mr. Stewart, if we can tame this engine down and have less power, we'll climb out more like a real Mustang instead of like the Jupiter missile we climb like now.
We'll keep you posted.
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The photo above shows the new crank trigger wheel, the original pulley mandrel, and a 1/4 inch thick steel retaining ring we had fabricated to better spread the load of the three retaining bolts. The damper is the same fluid damper we had removed. Our new elastomeric damper wasn't drilled for the pulley mandrel we are using, so we reinstalled the original. The point of this setup is to get the engine back together enough to ferry her down to Bartow, where we will go further with the changes we discussed last month.
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Above you see the pulleys and belts reinstalled and ready for runup.
Below, Doll sits after a successful runup and leak check on Sunday February 2nd. Within a few more weeks, we'll get her recowled and ferried to Bartow, where we'll probably pull the engine, install a new hydraulic cam and lifters, drop the pan to make a visual of the crankshaft section, install the new damper, and possibly re-engineer the pulley setup.
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Saturday, February 15th: The flight from Montgomery down to Bartow was perfect: Engine ran fine, tailwind, clear blue sky, as good as it gets. Waiting in Bartow was a great group (hate we didn't get a photo) including Jack Peck (S51 Merry Mary), Dan McGarry (S51 Top Duck, the first kit to fly), Kevin Armstrong (S51 in England almost past the inspections and paperwork required by the CAA in Great Britain), Frank Zersky (recently bought partially completed kit and is beginning his work), and Harry Stenger and Neil Butterworth of Aero Fabrication. We'd have insisted Jim Stewart be there, but it was an impromptu gathering that just sort of happened, and we didn't have time to get Jim and Peggy on board.
Even with the engine performing so well, we still went ahead with our plan to pull it for the mods we discussed earlier. Spent Sunday disconnecting and draining, and had the engine out of the frame by noon Monday. Harry will now remove the cam for regrind to a "milder" hydraulic set-up. We would like to have this work done and flight-proven by Sun n Fun, but it probably won't happen, given the way these kind of jobs go, and the delays that creep in. We want to get this engine smoothed out at idle and log more time on it as part of the longer range program, and missing Sun n Fun again might be one of the prices we pay. We'll see.
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Above, the 588 in the sling coming out.
Below, on the stand for further disassembly.
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Harry and Hank will be moving the project along for the next two weeks. I'll try to get back down weekend after next and "help." Like Hank said, "You can help and we'll have it pulled by Supper, or I can do it alone and have it out by Lunch."
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You are looking above at the base flange and the oil spray tube for the PSRU.
As we were disassembling the PSRU, we found the broken tube and began to theorize as to why it had let go. There is, of course, vibration in the box and the engine. We will also be checking alignment to see if there was any side pressure at the O ring end that might have contributed to the failure.
In having new tubes manufactured, we had already decided to fabricate with a constant diameter rather than incorporate the turned down sections that this tube has. It's simpler to build. This will allow us to have more material in the tube, which might allow us to overpower this symptom even if we can't eliminate it. No one else has had this failure that we are aware of.
The other conclusion we have reached is that we will not put any more effort into evaluating this particular 588 engine. We will, instead, back up and build a 502 based engine. Jim's prototype flew about 400 hours with a 502, Jack Peck is approaching 300 hours in his 502, and Hartzell has already approved the PSRU with a 502. The 502 generates plenty of power and is a proven concept. We can build wi th a shorter crankshaft throw, hydraulic lifters, shorter rods and different pistons for a lower compression ratio; an elastomeric damper, fully electronic fuel injection, and a wet sump. Al assures us that this 588, with the milder hydraulic cam and lifters, new damper, and tuned fuel injection can run "like a pussycat." Other engines might work, but we are going back to the tried and true 502.
We will be getting the 588 from Bartow to South Carolina, along with some other engine cases, cranks, and parts from Montgomery, to see what we can use from what we already have. We'll be down longer than we wished, but believe that taking two steps back will get us further along in a good direction than continuing to develop the 588.
Below, you'll see the area on the bottom of the tube that was rubbed by the gear. Jim had designed the units to be lubricated by the jets in the tube as the gears come out of mesh. The tube stayed in pretty close relation to its intended position, being held by the O ring end of the tube in the boss receptacle in the center case. Had the tube come out, it looks to us like the tube would have been kicked to the wall of the case and settled in the case sump, rather than, if it had been on the into-mesh side, been pulled through as scrap steel through a shredder. Out-of-mesh is the way to go.
We'll keep you posted.
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During late March, early April, Harry shipped the 588 engine to Al Joniec and Robert Abernathy for evaluation and recommendations for our next steps. We also delivered two other blocks, two cranks, cams, lifters, and other engine parts we had bought and stored for the kit and the prototype as choices from which to pick components for the next build. Mike Goranski met with us in South Carolina to go over these items and think through changes he might make in his engine setup. We had a very, very interesting and educational session with Al and Robert that Friday.
After evaluating and discussing, we have decided to build a 540 cubic inch engine for Doll, and a 500 cubic inch engine for the kit. The 540 will use the dual plug heads, distributor and crank trigger ignition systems, hydraulic lifters, wet sump, and the AirFlow fuel injection unit. The 500 will differ primarily by having a state of the art fully electronic fuel injection system with single plug heads.
For now, we have sent the Airflow unit to Rivera for a full overhaul and calibration, and are selecting parts for the 540 buildup. We'll report as these engines come together.
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Above is a photo I took last weekend of the firewall with the external oil tank and other systems in place as required for the previous dry sump lubrication system, and below is a photo after removal of the tank. The oil will be carried in the new engine in the pan, hence the term "wet sump." There are tradeoffs in using one system vs. another, but we think that the success Jack Peck has had, and the relatively low RPM (4750 Takeoff) we are using says that a wet sump system is fine. Continental and Lycoming are wet sump, most cars are wet sump, and going wet sump eliminates much of the external oil lines we were having to use. A dry sump system does offer some advantages, but none we think we have to have.
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Wet sump firewall without external oil tank.
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Harry's hangar cat helped through the morning but was just plumb tuckered out by afternoon.
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Great news from Kevin Armstrong in England: After six long years of working with the Civil Aviation Authority in the U.K., his Stewart S-51 flew again!
I say flew again because this airplane originally flew in the U.S. under ownership of the late Sheridan Owens. Kevin bought the airplane and had it ferried to California, disassembled for shipping, floated to the U.K., reassembled, and has undergone inspections and proving and documentation and engineering data for the CAA, and, today, watched as his U.K. appointed and approved pilot took her up for two short flights.
The first flight was a ten minute ops check, while the second was a thirty minute flight envelope procedure. Got her up to 230 knots at approximately 3,000 feet at 4,000 RPM.
Congratulations to Kevin and thanks for the time and effort he put into working through the CAA requirements to get her airborne in England. He'll have his pilot go for five total hours, then Kevin will take the controls and have a go.
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July 2014 News and Events
Most of June was spent collecting components for the new engine build. Our new reverse rotation / reverse polished crankshaft arrived in South Carolina mid June, but travel schedules and other summer activities have delayed final assembly.
Our engine guru, Al Joniec, is seen below on his recent trip out west advising and consulting with a west coast car collector. Al got him straightened out on a few things and is now ready to finish up our engine. Our engine should begin going back together the second week in July. We'll be checking proper indexing of the existing PSRU rear case and the newly manufactured rear cases on this new engine.
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Above is a shot of the original design spray bar for the PSRU, with the new design on the right. Jim Stewart approved the new design, going with a constant diameter tube rather than the turned-down design. These new spray bars have been built by Bill Locher, who has been immensely helpful in thinking through the new design, checking and double checking dimensions and design. You'll notice that the new spray bar is also longer than the original, and has provision for two "O" rings at the aft end. This allows the bar to seat more deeply in the socket in the center case for a more secure assembly. We'll be installing this new design in Doll's PSRU.
We will be at OSH this year, but will not have Doll ready to fly her up. We'll be with the Replica Fighters guys or at the Visit Pensacola booth in the exhibition hall, right next to the Sun n Fun booth. Please stop by and see us.
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