Stewart 51 Partner LLC
Ole Ringstad, pictured above, recently displayed his BMW based 12 cylinder engine and related systems at Aero 2019 Exhibition in Friedrichshafen, Germany.  There is a YouTube interview of Ole available in which you can hear his update and see the engine as he displayed it.  Search AvWeb Video on YouTube and look for "Ole Ringstad's 12 CYL Sport Engine."  Ole plans to begin testing soon.  We are all pulling for Ole to successfully develope this powerplant.  He has put a lot of thought and effort into it and is close to running and proving.
Doll Ground Runs
John Baughman and Curtis Godfrey assisted with installing the prop (Well, actually, they did all the work on installing the prop!).  These fellows manned fire extinguishers and stood ready as we performed the first run with the prop on.  As noted in our earlier post, the run went well, discovering one oil line that I had failed to tighten properly.  Other than that, she did fine.  Another run a few days later went well, also. 
Above, we have laid out the left and right wing ribs on their respective rib blocks from Wing Station 150.00 (tip) inboard to 43.25 to measure for extending the blanks, and thus, the rib nose further forward.  This is a small detail that is not absolutely necessary for structural purposes, but it will allow for one more rivet forward, which will more closely match the original ribs.
We began a Condition Inspection on Doll in March, using the Inspection Checklist on this website.  Below, Brendon Doherty working the left main while I worked the right.  Should finish up mid April, when we will perform our final ground runs, put all the panels and covers and fairings back on, and get her ready to fly.

We'll keep you posted.
April - June 2019
The Spring Quarter saw slow progress on our condition inspection, such that we do not anticipate getting Doll to Oshkosh this year.  We had removed the prop governor mounting bracket to allow Robert Abernathy to reproduce it for Mike Goransky's engine and our new engine for our respective S51's under construction.  The removal, turnaround, and reinstallation ate some time.

If you are attending Oshkosh this year and want to visit with a few S51 participants, come by the Replica Fighters Association building Wednesday July 24th at 3:00 for a couple of short presentations.  I will update current builders on our parts production progress and Cliff Fitch will unveil a new hydraulic component for the main gear up  lock we will be offering.  We might also have a visit from test pilot Elliot Seguin, who has been flying Rod Bower's S51, his schedule allowing.  Another possible drop-in is a gentleman we are visiting with about assembling our Fast-Build kits.  Join us if you can work it into a busy day at AirVenture.

Bill Keyes might have his turbine S51 up again this year, but will probably be the only realistic prospect to make it this year.  Jim Gohm has had several good flights toward his 40 hours out in Prescott, Arizona.  Cliff Fitch has flown several times lately toward his.  We are getting our condition inspection finished and about to start more ground runs, then reassemble for flight.  Jack Peck is close to making repairs to his main gear.  Parker Miller and Pat Stanley are adding an oil cooler to their project, and are close to flying.    Maybe we'll have a good number of S51's at Oshkosh next year.

July - Oshkosh - News and Events

Several builders and other interested parties plan to meet at Oshkosh in the Replica Fighters building Wednesday afternoon the 24th at 3:00 Central Time (2000 Z).  We'll see a new design for the main gear downlock converting it from a mechanically operated to a hydraulicly operated mechanism, sample parts from D & D Classics, and an unorganized slide show on my laptop of random S51 subjects.  If you have time and want to learn more about building and operating S51's, feel free to join us.
August 2019
We made several ground runs through August, into September, refining a few changes and checking results.
The photo below shows our run to check proof-of-concept of a coolant overflow recapture tank and running with all fairings and cowling (except this right piece to observe the coolant overflow tank) installed.  Running with fairings and cowling installed seemed to make a difference in the effective air flow through the radiator scoop.  We had heard about an episode years back where Jim's prototype had flown and had the inner gear doors drop open.  Visualize the doors hanging straight down under the belly, just in front of the radiator scoop inlet.  The disrupted airflow caused an increase in the coolant temperature.  We figured we had better run with as clean an aerodynamic condition as possible.  It was 94 degrees Farenheit late that morning as we ran.
The tank we tested was a plastic coolant overflow / recovery tank system that you see on most automobiles.
Up until now, Doll has flown and dumped excess coolant overboard.  By adding the tank we will recapture and generally have more than enough coolant on board at all times.  The system worked as it was supposed to.

Below, you'll see the Moroso tank we are installing as the final configuration.
We plan to be flying again by the end of September.  It's a plan.
On the west coast, Rod Bower and friends (Jim Czachorowski, Jim Gohm) got Rod's engine installed and Elliot Seguin got back in the saddle and took her up.  The flight went fine but for a flickering warning light.  Sounds like the sending unit was the problem, but congratulations to the Bower team for getting back off the earth.

We have received several crates of engine cowl stretch-formed pieces from Mooney.  Have not had time to get them out and check them closely, but will have to soon.
September/October 2019
Above, you are seeing one of the most amazing S51's ever completed taxiing out for its first flight. This airplane was built by Parker Miller and Pat Stanley in the Houston area, at the Pearland Airport.  Notice they have covered the rudder in aluminum and polished the entire airplane.  I have seen this airplane in person, and I can tell you, it is one fine example of the highest levels of craftsmanship and excellence we will ever see in an S51 or any other aircraft.  It is a stunning airplane.
And here it is, in the air, with Pat at the controls.  A great day for Pat and Parker and everyone following the Stewart S51 program.  Nineteen years of patience and perseverence finally put air under the wings of this S51 and rewarded these two men with one amazing airplane.
Congratulations to Parker and Pat! 

Doll Airborne Again
On Tuesday, September 24th, Harry Stenger and I flew from Harry's Aero Fabrication and Restoration to Pensacola to get Doll ready for her first flight in two and a half years.  Harry came up to Pensacola to check the installation of the engine and perform final ground runs. 

On Friday, the 27th, with everything to Harry's satisfaction, I launched on Runway 26 at KPNS and climbed out to the northwest, the engine feeling great, prop performing properly, gear up just right.  Then I began scanning the instruments and saw the oil temperature climbing faster than I was.  I had to tell the tower I was entering downwind and needed to land, as the oil temp had gone a bit too high.

All other instrument indications were good:  Oil pressure looked fine, coolant temp looked fine, and the landing gear came down fine.  Normal approach, decent landing, cleared the runway, and the oil temp began to come down as I taxied in.  A much shorter flight than we had wanted, but a flight, none the less.

Harry and I began to investigate, were on the phone with Al Joniec and Robert Abernathy, our engine guys, and a few other folks, looking for answers:  What was different from the engine and systems in September 2019 than what we were flying in April 2017 and before, when we had good oil temps?  Jim Czachorowski and Cliff Fitch weighed in, we sent photos of engine components around to everyone, opened up the back end to check for blockages in the oil system, spoke and emailed Dart (engine block builder) technical services about oil flow passages, and finally centered in on the oil filter adaptor.  Something had been modified on it.  Turns out the fellows at Robert's place had modified it to make their dyno runs and had not installed a proper flow pattern adaptor similar or just like the one we had been running.  This prevented oil from being properly diverted to the oil cooler, thus the high oil temp.  Mystery solved.  We think.

We are pausing now to make a few other tweeks to the oil circulation system to simplify the plumbing and circulation pattern, given where we are with it right now has been reached through evolution and patching in to the old dry-sump system we evolved from in 2014.  The research and experimentation continues!
November/December 2019
Going back to our oil temp issue of September's flight, you'll see, above, the oil filter / flow adaptor on the left, which was installed on the engine.  This one did not correctly route oil through the oil cooler.  We ordered and installed the adaptor you see on the right to simplify oil flow in the system.

The photo below shows the fittings installed, the next one down shows the adaptor installed in the engine block where the old adaptor and oil filter had been.
The "OUT" line (bottom line in photo) routes to the remote oil filter pad, shown below, then to the oil cooler, then back up through the firewall into the engine via the "IN" fitting, then on to bearings and auxillary needs.

The manifold shown below allows oil routing for several functions:  Prop governor supply, Preoiler output into engine, supply for PSRU lubrication through oil jets, and supply from one of the engine oil pressure sources.  In the old setup, there was also a pickup for oil pressure gauge supply.

The view below of the remote oil filter pad shows where we relocated the oil pressure pickup.  There is a dramatic difference in oil pressure indication from the old pickup to this one, given the changes we made.
We hope everyone had a good 2019, and that 2020 will be a good one, also.