Vision prototype photo

Vision prototype photo
This is the Vision prototype designed/built by Steve Rahm in USA. and still being supported by Pro Composites Ltd. in USA. The aircraft is a 2 seat side by side, scratch built from a series of manuals. Built entirely of fiberglass and carbon cloth material the builder needs to know or learn some of the easy basics of composite construction. Building began Feb. 1998 in my spare time with 7 years where no building was possible. Building Hours at February 28, 2022: 4248.--------------------------------------------------------------------------------------------------------------------------------Some short videos of flights are at: https://www.youtube.com/channel/UCfxJXIwvmfNlNF3gwplFw7Q

Saturday, October 26, 2024

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.

Wednesday, October 9, 2024

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