Fourth Test Flight 2.5 hours

 October 26 2024

Finally it appears I can begin to leave the airport area and get into my engine break in hours and count down more of the 20 hours of experimental aircraft flight time required within 25 miles of my local airport. Conditions for this test flight were, as of 10 am very light winds at the surface, temperature plus 4 degrees C, sky mostly clear.  After getting up to 7000 feet (3000 ft agl) as directed by ATC Calgary for this flight I found the winds were from the west at a constant 27 knots and the temperature after 30 minutes had climbed to 14 degrees C. My ground speeds were quite different if travelling east or westerly in direction.  Average ground speed was about 158 knots as best I can determine. An added bonus to todays flight early on in the flight was I was able to use the cabin heat for the first time, it was cozy warm inside the fiberglass foam insulated cabin.

After many delays with engine problems and the minor modifications that were required I was able to get up in the air once again to test the engine.  Finally I was  able to get a long flight time with everything functioning as it should. 

1.  Engine popping and back firing. As mentioned this was due to a spark plug fouling issue with the rebuilt engine making the plugs wet with oil in within about an hour of running the engine. This has been rectified by cleaning my own plugs and using a clean set before each flight test attempt. Having a backup set of plugs seems to have cleared up this problem until the engine rings get seated properly which will reduce the oil contamination in the cylinder head. 

2. Fuel pressure loss has been rectified as per the details in an earlier post on the subject along with the fixes required. When the engine gets up to 215 degree F on the ground I still have to use the boost pump to stop the pressure from dropping.  In the air during flight the boost pump is not required as the engine cooling and oil temperatures have dropped significantly. I plan on building a blast tube and shroud covering the mechanical fuel pump which a fellow builder has also had to do on his custom RV6 with a bigger engine.

3. Radio noise on my Dynon radio appears to be coming from the Skyview screen itself on frequency 123.4 and to a slightly lesser amount on 128.7 the air traffic frequency.  Raising the Squelch on the Dynon screen setup menu has cleared this up.

4. The Alternator charging has been fixed and was found to be a poorly manufactured 60 amp fuse link module where the connection to the fuse inside of the holder was faulty causing an intermittent connection.  The alternator came back from the test shop identifying it was in perfect running condition.

Oil Cooler Ram Air Intake

October 9 2024,

Due to the fact that I have been having issues with my Mechanical Fuel Pump on the engine getting to hot I wanted to see if I could reduce the engine oil temperature to some degree.  My engine baffling takes air from just in front of cylinder #2 into a horizontal round 3" diameter flange.  Then routes the air via scat hose to the oil cooler which is mounted on a stand off bracket from the firewall.  I believe that the air entering the cowling  is mostly going into the high pressure cavity above all cylinders.  As a result I believe the airflow into the scat hose from the horizontal opening is somewhat restricted.

I have fabricated a custom 90 degree Ram air intake scoop out of fiberglass to sit inside the 3 inch diameter flange at front of cylinder #2.  I carved a shape out of foam then glassed over it making sure the downward tube fits perfectly inside of the flange.  The opening of the intake across the bottom edge is then lock wired in two locations to the lower cowling intake lip using 24 gauge wire.

Results of this ram air to oil cooler has proven extremely beneficial as my oil temperature has gone from 203 F to 179 F a reduction of 24 degrees fahrenheit. 

End

Third test flight for 1.2 hour cut short due to Alternator charging intermittently.

 August 14 2024

After many times doing ground runs to prove problems have been solved I finally got up in the air flight testing.  A clean set of spark plugs were installed so as to alleviate any popping/backfiring or oil soaked plug conditions.  As noted from my first test flight balance was a bit nose heavy.  This time I had 25 pounds of lead in the baggage compartment and the same amount of fuel.   Using pitch trim I was now able to trim with almost full up nose trim.  I completed a 1.2 hour flight adjacent to the Springbank airport CYBW under radar control of Calgary VFR terminal control.  Fuel pressure is behaving much better now that the fuel lines were made as short as possible and then wrapped in a thermal blanket on top of the existing firesleeve.  The heat deflectors on the exhaust pipe locations is also helping keep heat away from the fuel lines.  Engine ran very good with all CHT and EGT and Oil temperatures staying in the green.  The Manifold pressure was stable at about 21.5 inches and I was running 2450 RPM at 6000 ft and 6500 feet altitude averaging about 156 knots groundspeed.

My flight was cut short once again as my alternator problem continues to give me grief.  It worked for a while after startup then quit for a while then came on again for 2 minutes and then quit for good 1/4 way through my flight.  I have good instrument and audio warnings of my voltage and my amps draw so continued the flight until the battery was showing 11.7 volts and then requested to land right away.  Landing this time was really good although in the flair I did a couple of little floating up and down before it settled firmly on the runway.  I focused on the centerline giving the rudder immediate corrections and had a very good roll out this time.  I am very happy with the modifications I made  to the tail spring and steering links.

In two days I am taking the alternator into a repair shop to find out why it is not giving constant output.  Now I will spend some time to try and figure why my radio is hissing loudly when not transmitting.  Something to work on while the alternator id away.  Ps the alternator came back from the shop testing in perfect working order.

Flight test cancelled Fuel pressure dropping excessively

 July 8 2024

Below a heat deflector is mounted above the port exhaust pipe.

I planned on doing a flight test but only got as far as the runup area when my fuel pressure was dropping down to .2 pounds from the normal 2.5 to 3.5 pounds.  The tower controllers allowed me to backtrack on the taxiway quite a ways as I made my way back to the hangar.  A couple of builder friends came by to give me some feedback on my fuel lines and the possibility of high heat causing vapour locking in the fuel lines.  It was recommended that I shorten the two fuel lines as short as possible then wrap them in a reflective heat blanket material on top of the fire sleeve.  They also recommended that I build 3 separate heat deflectors to clamp onto the exhaust pipes in three locations, two close to fuel lines and one to protect the starter and alternator.

Below a heat deflector is mounted above the starboard exhaust pipe.

Below a heat deflector is mounted above the front crossover exhaust pipe.