Monday, December 1, 2014

FIRST FLIGHT since 1984.

Dan Linn Photo

On November 14, 2014, the St. Louis Robin took to the air once again after 30-years of earthbound storage.  For many, the occasion was the culmination of a lot of hard work and marked a major achievement toward ensuring a bright future and new milestones for this historic airplane.  And no time was wasted to begin making new history, for on the following day, November 15, 2014, history was again made by lifting two notable passengers into realization of their ancestral ties with the record-setting flight this airplane made in 1929. 

We'll discuss more about these passengers soon, but for now, I wanted to take this chance to give a full update on the flights.


So far, we have six takeoffs and landings on the airplane.  Three on Friday 11/14/14, and three on Saturday 11/15/14. These flights totaled 1.6 hours.  Pilot, Kelly Mahon did the honors and was just the right man for the job.  We were all relieved to know that the engine ran well and the airplane performed great.  

Dan Linn photo.


I have to say that last week was a phenominal week.  Between the first start on Nov. 8th, to the first flight on the 14th, our team pulled off some amazing work. After the first engine runs, we had to remove much of the engine components and some of the interior furnishings to give Craig Gunder adequate access for a major weld repair on the forward fuselage frame.  Honestly, I was afraid that this process was going to throw the whole project off schedule by a week.  With Kelly here to fly, we all felt the need to make it happen on schedule.  Lon, Craig, Kelly, Randall and Myself really got a lot done to make it happen.  Randall and I had our day jobs to do, and so we showed up each afternoon after Lon, Craig, and Kelly had already been working all day on the plane.  We (practically) worked in two shifts and were absolutely working on adrenaline.  I had planned a month ago that our first flight goal was Nov. 12th.  That was before realizing how bad the rusted tube was.  So, I am so pleased that we got it done and into the air only 2 days behind schedule.... thanks to an outstanding group of guys and my wife and mother-in-law who fueled us every day.

Terry and Craig going over the repair as Kelly works inside.  Photo by Jared Calvert.

Craig Gunder (Gunder Restoration & Design, Inc.) cutting away the rusted tube.


It was phenominal to share in the excitement of the first flight.  You just cannot imagine what this airplane is like to hear and see coming to life.  It is truly a special machine.  The engine is performing well, but has developed an oil leak.  We had already repaired one oil leak in the sump area before 1st flight and we confirmed it no longer leaks there.  But the new leak started showing up in the nose section around the third flight (11/14/14).  It has gotten slightly worse on every flight.  So far we have not pinpointed exactly where it is coming from. It is possibly coming from the seal between the crankshaft and engine crankcase.  We decided to stop flying until we can find and fix this leak.  Also we had a partial failure of the pilot seat, which Kelly temporarily repaired with some bailing wire.  It is not really a good feeling to fly with this repaired seat and so the airplane is grounded until the seat can be fixed.

On the first flight, our Pilot Kelly Mahon reported that the engine RPM was revving up above 1650 RPM at full throttle but the airplane wasn't climbing very well.  This meant the propeller pitch was too flat.  So we made an adjustment to add 3 degrees (coarser angle). On the second flight with this setting, the RPM was just below to the desired 1600 RPM at takeoff.  So before the 3rd flight, we adjusted back 1 degree (flatter angle).  The 3rd flight proved this to be the optimal setting for the propeller.   It seems the takeoff distance reduced by about 150 feet by the 3rd flight as compared to the first.  We are happy with this setting. 
Also it was pleasing that our intercom system worked flawlessly for communication between the pilot and passenger as did the radio communications between the pilot and ground crew who had a hand-held radio.


Also, on the first day, the outside air temperatures were around 35 F.  As a result, it was hard getting the oil up to the recommended operating temperature. We would like to see 160 F or more but we never got it above 140 F. Therefore the oil pressure was higher than the recommended range (60 to 90 psi).  Kelly decided to fly after about 30 minutes of ground run, even though the pressure was still a little high.  On that flight the pressure settled to about 110 psi at the cruise power setting. We removed one spacer from the oil pressure relief valve and on the 2nd flight the pressure settled to about 100 psi.  So we removed another washer and for the remaining flights the pressure was showing about 95 psi.  This should come down in warmer weather. 

The flights on Saturday were just about the same as the 3rd flight in all respects.  Outside air temp was a bit colder, around 32 F and had dipped to 24F overnight. With blankets over the engine, I left our work-light plugged in all night.  The next morning, we used a hair dryer to warm up the oil tank for a few hours.  With pre-heat all morning we got the oil temperature up to about 49 F by the time of engine start around 1pm.
We found in cold weather, it takes a lot of fuel priming to achieve cold start. One other thing we learned is that the battery and starter we have are GREAT!    It took a lot of cranking but the starter and battery did not miss a beat.  As we learn more, we hope to develop a good start technique so we can minimize the wear and tear on the starter.  I am glad we had them an were not using the hand crank or worse, hand propping.

As for the airplane rigging in general, Kelly was pleased.  We had kept the wing wash-in (twist) settings as they were already set previously by Joe Erale.  With no adjustments, Kelly says it flies level.  He did not do any stalls yet, so we will evaluate this a bit more when we get to the point of testing stalls.  This will tell us more about the stability.  If it has a tendency to drop a wing during stall onset, it may require a small adjustment.  But we are certainly sure it is close to perfect already.   As for the tail (horizontal stabilizer) trim adjustments, we had adjusted them to be level with the hangar floor when the trim lever was in the neutral position.  Kelly says that this is pretty close.  The plane does not like to settle in for a 3-point landing as it is a bit heavy on the nose. Instead, it tends to settle on the main wheels (aka Wheel Landing) unless you apply some propwash across the tail. This takes a bit of pilot finesse. Wheel Landings are ok, but tend to take a little more runway.  This is also how my dad's Robin flies... I think it is pretty typical of all Robins.  I look forward to evaluating these things more when we get some warmer weather.  

Kelly's huge smile says it all...


For now, the seat and oil leak are the priorities.  We have some bad weather coming this weekend so I may not get a chance to troubleshoot the engine oil leak.  But in the mean time, we are getting prepared to build a new seat.  Next week, I plan to go remove the seat from dad's Robin so we can make measurements from it.  We will build a steel frame seat and have it wicker-covered to match the current wicker.  We will include the ability for adjustment.  The simplest way will be a design that is ground-adjustable only.  I am looking at some other seat designs now to find the best.

By the way... all of the paperwork was also completed last week and the airplane is legally returned to service.  Logbook entries are complete.  We filed four FAA form 337s' with the FAA documenting the major repairs and major alterations that were done.  The airplane is deemed airworthiy until this time next year when its next annual inspection will be due.


As I mentioned, two of the flights Saturday were of historical significance as they were with passengers Pat Holoyda (Forest O'Brine's grand-daughter) and Clarine Andresen (Dale Jackson's grand-niece). More on this next time.


  1. Check out the pics we just posted over the weekend of our certificate and photos of this very plane, from 1979.

  2. Great read and so cool to be there on the 15th to see it fly!


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