With about 19 hours on my RV-6A, I was having trouble convincing myself to stop flying and finish the wheel pants and gear leg fairings. But knowing I needed to do that soon, I wanted to try and document the performance improvements the fairings would make. The charts below are a snapshot of N731CK's climb performance with no wheel pants or gear leg fairings installed. I only did a single data run at 100 KIAS on 17 January and the other speeds (110, 120, 130 KIAS) were run once on 11 January and again on 17 January with the average results used. All data was taken immediately after speed was established on initial climb out, so data collection generally started at 500' or 600' MSL and continued through about 2,500'. As of time these runs were performed, I was still running on mineral oil with less than 20 hours on the engine. So CHT's were still an issue during climbs. I stopped climbs when CHTs hit about 400F-410F. Outside air temperature at ground level was around 70F on those days. I'll have to wait for cooler temperatures and change from mineral oil to do climb rate testing at less than 100 KIAS; just couldn't keep CHTs low enough for my comfort when I did these first timed climb tests.
Data was collected using a simple digital voice recorder. I plugged a small microphone into the digital voice recorder, stuck that microphone inside one of my headphone earcups, pressed record and everything I said during the flight was recorded. It was easy to download the file from the digital recorder to my computer and then use the time scale during playback to determine time intervals for each altitude.
Here's the charted climb rate performance as of 17 January 2009 (I'll update when I have data with fairings installed):
At about 19 hours flight time during my Phase I test flight period, I noticed a problem with the heat muff on the lower, right side exhaust pipe. The heat muff was installed per the directions provided when I bought it, but it appears to have "blown out" the end caps. I'll have to take it apart to inspect the exhaust pipe and order new parts to secure it, but I need to figure out what happened here. It appears I tightened the hose clamps too tight, although I only tightened them enough to hold it all in place when I installed it. I'm guessing that the heat of the operating engine and some dissimilar heat expansion coefficients of the metals used caused the extra stress that squeezed the end plates out.....but I'm not really sure.
Here's what it looked like when it caught my attention:
Forward end of heat muff:
Closer look at the forward end of the heat muff:
And same thing on the aft end of the heat muff:
Will post the resolution of this issue once I fix it.....
This page was last updated on 12/18/11.
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