Flight Testing Complete!

We did it!

The forty hour flight test period has been completed.  Big thanks to EAA staff Kyle Voltz and Tim Hoversten for completing the 40 hour test period (and, of course, Tracy Buttles for performing the first flight).

Here Kyle is making the logbook entry officially signing the aircraft out of phase 1 flight testing.  IMG_9423

The nice part about using the EAA Experimental Aircraft Logbook is the logbook entry is already pre-printed and all you have to do is fill in Vx, Vy, Vso, gross weight and C.G. location.IMG_9433

Kyle is all smiles showing off the logbook.IMG_9434

We are now able to fly anywhere in the country and start taking passengers.  So our first destination is the Zenith Open Hangar day on September 19/20, 2014.  We will also have EAA’s One Week Wonder, that was built by volunteers during AirVenture Oshkosh 2014,  at the Open Hangar day.

Hope to see you there!

Until next time…

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High Cylinder Head Temps & Cowling Changes

We have been working our way through our flight test program.  However, high CHTs kept us from really making progress until we made a few changes.

Continental’s guidance for the O-200A limits CHTs to 525 degrees max with recommended max during cruise of 420 degrees.  We were seeing peak temps during climb-out of 505 degrees, within the max, but still hotter than we wanted.  Plus, the temp wasn’t really falling in cruise.

We are using Mike Busch’s free Savvy Analysis software to painlessly analyze the data.  I strongly recommend it if you are using a Dynon or any other engine monitoring system that stores data that you check out this software.

Here is a graph of one of our early flights.  It shows a peak CHT on cylinder #3 of 505 degrees and a cruise CHT of 480 (note the red line is set at 480 degrees). Savvy1

We are not running an oil cooler.  Oil temp was high but we were below the max allowable of 225 degrees.

What to do?
We focused our attention on the cowl.  In order to draw more air out, we added a bigger lip to the cowling.  For now, we just duct taped in place.IMG_9421

This helped but we still needed more airflow, especially on cylinder #3.  Here you can see the inlets.  Cylinder #3 is on the left in the photo and #4 is on the right.  Note how much more air is hitting cylinder #4.IMG_9358

Here is a close up of the opening in front of cylinder #3.  We were concerned that the air coming in was skipping past this cylinder.IMG_9339

Here is the inlet in front of cylinder #4.  Note how much more of the cylinder is exposed to the airflow.IMG_9343

We decided to open up the inlet in front of cylinder #3 by trimming back the fiberglass and replacing it with an aluminum baffle.  The top green line is where the baffling used to hit the cylinder and the lower green line is after our modification.IMG_9418-Edit

Since we decided to go with a new lip, I cut off the old lip which enlarged the outlet as well.  Green line is my cut line.IMG_9384-Edit

Here is the removed material.IMG_9388

After each of these changes, we pulled the data and reviewed the impact.  If it helped, it stayed, if it did not, we tried something else.

During all this testing, the outside air temperature has dropped 10-20 degrees depending on the day.   Of course, this has helped quite a bit.  That said, our cowling changes have made a big difference and CHTs are no longer a concern.  In this graph, you can see that on take off the highest the CHT is under 450 degrees and in cruise at 2500 rpm we are sub 400 degrees.Savvy2

We will have to wait and see how we do next summer when the weather warms up.  For now, we are happy with the numbers and have really started to put some test time on the aircraft.  All other aspects of the testing are going as planned.

Until next time…

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We did it!

The staff built Zenith CH 750 STOL had a successful first flight on Tuesday, 8/12/2014.  Tracy Buttles was at the controls.  A big thanks to the staff members who worked on the aircraft and the companies that supported the effort by donating their products  (special thanks to Zenith Aircraft, SteinAir and Dynon Avionics).  It has been a wonderful learning experience for many EAA staff members.

Kyle and Charlie (me) checking the radio and avionics._MG_7587

Performing a static run up just to confirm engine performance after repitching the prop._MG_7600

Lined up on the runway.  _MG_7752


Nosewheel off._MG_7756 _MG_7758


Flying well before the 1,000 foot remaining marker._MG_7761 Climbing out. _MG_7773

Coming in to land._MG_7810 _MG_7813 _MG_7814

Touching down._MG_7816

Three wheels on the ground._MG_7817

Tracy giving the thumbs up after bringing her in._MG_7870

Everyone was all smiles after the first flight!_MG_7897Until next time…


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Airworthiness Inspection Complete!

Well, we made it!  The project is now officially an airplane in the eyes of the FAA.  When I took over the leadership of the EAA employee staff build, I set a goal of having it completed by AirVenture-Oshkosh 2014 and we received our FAA airworthiness inspection with one day to spare!  Thanks to all our team for putting in some extra time to make it happen.

FAA Inspector Ray Petersen examining the aircraft._MG_0674 _MG_0678 _MG_0696

Ray making sure the tank capacity and minimum octane is labeled and that the tank is properly vented._MG_0697 _MG_0718

It’s paperwork time._MG_0741

Our team fixing a couple of minor items that Ray discovered while I deal with the paperwork.  Fortunately everything Ray caught could be quickly corrected._MG_0753

The big moment!  Tracy, Tim, Kyle, Ray (FAA) and me (Charlie) accepting the airworthiness certificate and operating limitations.  Expect a first flight soon!_MG_0761A big THANKS to FAA Inspector Ray Petersen for being so flexible on the inspection date!

Until next time…

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Oshkosh or Bust – Airworthiness Inspection Scheduled!

Thanks to some outstanding customer support from Dynon and B&C Specialty Products, we received replacement parts that have let us recover from our misstep in time to still make it to #OSH14 with an airworthiness certificate.  No time for a first flight, but hopefully the FAA inspection and sign off will take place between now and the start of the EAA Convention.

Mapping out a game plan for wrapping things up._MG_0386

One of the final items was running the wire for the ELT remote._MG_0520

Securing the ELT antenna wire._MG_0556

Yes!  We have a working PFD again!



We are ready for the FAA airworthiness inspection!  The project will be in the Homebuilders Hangar at EAA AirVenture Oshkosh 2014.  Stop by and see it in person._MG_0370Until next time….

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