Performance

I took my first "real" X/C today, flying from South St. Paul MN/KSGS to Beloit WI/44C - about 220 miles or so. On the way out, I did 171kts TAS at 9500' on 8.2 gallons an hour. On the way back at 10,500, I did 169kts TAS on 7.9 GPH. This is with an IO-360-B1B (180HP), dual PMAGs, and Hartzell BA prop. Not sure if these performance numbers are good/bad/ugly, but I'm pretty happy with them!

I have the wheel fairings, etc. installed but still have to install the upper intersection fairings. That will happen this week. Then on June 1st it's off to the paint shop. After that, I'll re-do all the performance tests from phase one.

As I said after the first flight, "Had I known it was this much fun I wouldn't have taken so long to build it!"

Brad, those are almost exactly what I get for TAS/fuel burns as well. Not sure I'd get those speeds at such high altitudes as you did, but at 7 to 8k' I'd be right on those parameters.

Sounds pretty outstanding to me

That was my top speed (170.67 KTAS) burning well over 10 GPH. RV-6A, O-360 A1A. Well done.

Bob Axsom

Very nice...what rpm were you running. I typically cruise at 2400, burning 8gph, LOP, and see a consistent 160 TAS.

Hmmm, now I'm suspicious of my numbers. Although I did produce an airspeed correction factor during phase one, I'm wondering if it is still valid after the addition of all the fairings & re-rigging or if the numbers are a true reflection of the actual performance.

Still, it was a fun day and in relative terms I am very happy with the speed difference vs. no wheel pants/gear leg fairings. If I had more time before I have to drop it off at the paint shop I'd re-run the test cards now but I think they will need to wait until after.

I'll be sure to post back w/findings.

Thanks all!

Brad, as you probably did during your initial testing, the final arbiter of speed is to do four way (gps ground track compass directions) speed runs, keeping everything constant for a minute or so each way. There are excel sheets out there that will get exact TAS based on the four speeds.

Yes, that's what I did in phase one. I made speed runs at multiple airspeed and used the NTPS spreadsheet to determine the error coefficient for my installation. My assumption is that the IAS/CAS error is not affected by altitude, but perhaps this is not correct.

It doesn't seem likely that the addition of fairings would change that, but I've learned lots of things during this project that seemed unlikely to me so...

Who needs paint

Says the other unpainted RV at Beliot yesterday. I enjoyed the sharpie comments written on your plane, particularly "Bernoulli was here" written on the top of the wing.

Do you have paint scheme picked out? Mine is bare yet mostly because I can't decide colors and such.

ChiefPilot said:

It doesn't seem likely that the addition of fairings would change that, but I've learned lots of things during this project that seemed unlikely to me so...

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As your airspeed increases, the drag is more pronounced. A Cessna 150 only gains 3 MPH with wheelpants, while we, at near 200, gain near 9 MPH...as the airspeed doubles, the drag squares! So don't discount those upper intersection fairings.

Best,

tsneidin said:

Says the other unpainted RV at Beliot yesterday. I enjoyed the sharpie comments written on your plane, particularly "Bernoulli was here" written on the top of the wing.

Do you have paint scheme picked out? Mine is bare yet mostly because I can't decide colors and such.

Click to expand...

Thanks! I'm going to miss the ability to write on it whenever I feel like it; perhaps a white board marker will work

Yes, I've been refining an original paint idea for several years. It's almost completely finalized. The thing is I'm rather picky about it - it took me 11 years and 8 months to finish the thing so I'm not excited about just any paint scheme being applied to it.

Sorry I missed you there - perhaps we'll meet there next year or at another fly-in in the area!

I believe you (directly) over my house today on the way back in to KSGS (around 3 or so). (I'm just on the edge of the STP Class D)

RVs make great sounds when they fly over.

YES!!!!

ChiefPilot said:

Thanks! I'm going to miss the ability to write on it whenever I feel like it; perhaps a white board marker will work

Yes, I've been refining an original paint idea for several years. It's almost completely finalized. The thing is I'm rather picky about it - it took me 11 years and 8 months to finish the thing so I'm not excited about just any paint scheme being applied to it.

Sorry I missed you there - perhaps we'll meet there next year or at another fly-in in the area!

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We got our RV-6A quick build completed in only 8 years but your comments about the paint job are so in tune with mine it is inspiring. My wife Jeanine and I worked on the color scheme for most of the 8 building years as well. Extremely important part of the airplane.

Bob Axsom