Mailing List flyrotary@lancaironline.net Message #12529
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Can happen to us all was Phase one complete, official climb results disappointing
Date: Sun, 31 Oct 2004 22:28:12 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Message
Hey Rusty,
 
    Did I ever tell you about the time I put a new intake manifold on my aircraft and went out and topped 200 MPH (couple of years ago).  Well after announcing it on the other list, I got to looking over my data and found I had failed to convert the OAT from Fahrenheit to Celsius as required by the equation I was using.  When I did - I lost about 12 MPH {:<(. and had to announce that I had not made 200 MPH.
 
I have also found that conditions/factors  can team up to be exactly right at one time and less so at another.  For instance when I went out one time this week in my aborted attempted to reach Lake City I fired up my engine and after letting it warm up I went to WOT.  I know the tach hit 6000 rpm (at least above the 5900 mark) with the new prop and gearbox. Wow! was I elated.  But, subsequent runs couldn't get it above 5700 rpm (not bad but not 6000) {:>).  I think the compression is a bit better before the engine gets too warm and then it drops and so does static, but who really knows.  I am waiting for the weather to get just a bit cooler and I think I'll hit 6000 rpm static repeatedly.
 
I find your data very interesting.  While I still need to do more testing, my best ROC with the new combination still appears to be 120 MPH IAS.  I consistently get 1600-1800 FPM now and have even pegged the VSI at 2000 fpm on one occasion.  I attempted one time to use a slower airspeed but it seemed to load the engine and my ROC decreased.  But, these are preliminary data.
 
Still all said and done, I don't think 2000+ FPM is topped by many RVs no matter what the claims are.  Here are a couple of examples from the CAFE tests - bout as good as it gets.
 
RV-6A
   180 HP 70x74    1238 FPM
RV-4
   ?  HP   CS          3308 FPM Dave Anders' 250 MPH RV-4 (couldn't find a report on a more typical RV-4)
Rv-8                      
   200HP CS          2176 FPM
 
So from what you have shown so far I say you are in excellent company - Keep it up.
 
Ed Anderson
----- Original Message -----
Sent: Sunday, October 31, 2004 7:09 PM
Subject: [FlyRotary] Phase one complete, official climb results disappointing

Greetings,
 
Posted below are the details of today's final phase one flight.  I'm truly at a loss to explain how I saw 3000 fpm yesterday, because I sure couldn't do it today.  I know I've seen 2500+ on a couple of occasions before, but not today.  Sorry to get everyone (particularly myself) overly excited about the climb rate.  I'm still not sure how I'm getting 500 fpm less than Tracy, while running the same prop, and rpm.  Oh well, the testing will never really end, which is what keeps it all interesting. 
 
Cheers,
Rusty (grilling steak, and drinking beer now)
 
 
 
 

10-31-04  1.9 hours  /  40.0 total

 

I finished up the climb testing, and did some descent testing.  Unfortunately, I must have been seeing things yesterday when I though I saw 3000 rpm.  Either that, or it was a bit of an extended zoom climb.  The real figure is 2222 fpm, which is almost depressing, but it was 85 degrees, and I have full fuel, so I’m sure I can improve this with better conditions.  The goal is still 3000 fpm, but I’m wondering if I’ll make it now. 

 

The main climb test was done at 4000 ft.  I started at 3500, then established a climb at the designated speed.  Once it was stabilized, and I passed through 4000 ft, I recorded the reading from the VSI.  This was just to get an idea of the best ROC, without regard to the actual figure. 

 

Climb testing :  mph  /  fps climb

  90  /  2100

100  /  2200

110  /  2000

120  /  1900

130  /  1700

140  /  1400

 

Since 100 mph was the best, I dropped to 1500 feet, established 100 mph at full throttle climb, and timed how long it took to get from 2000 to 3000 feet.  The average of a few runs was 27 seconds, which calculates to 2222 fpm.  If nothing else, it shows that my VSI is pretty accurate. 

 

I also did some descent rate testing around 3000 feet.  Basically, I went to idle, and noted the VSI descent rate at the following speeds.

 

Mph  /  fps descent

  80  /  700

  90  /  900

100  /  1100

 

I had added a trim tab to the (new) rudder, and found that it wasn’t quite enough.  It’s amazing the power it has though.  In high power cruise, I still need a little right rudder (added more trim after the flight), but in descent testing, I had to add a bunch of left rudder to counteract the trim tab. 

 

I also tried to un-squeeze the trailing edge of the new left aileron, to try to correct a little left rolling motion that was aggravated when I replaced the aileron.  It may have been a little better, but it still took some trim.  After the flight, I gently squeezed the right aileron a little, so we’ll see if that helps more. 

 

Finally, this concludes the phase one testing.  I had to circle around the area for the last couple tenths to be legal, but it’s done.   The airframe itself has behaved just as any RV should, and since I did fairly through airframe testing on my previous RV-8, I was able to get through the testing of this plane fairly quickly.    Just gotta love Van’s RV’s :-)

 

Now that the official time is over, I plan to pull the cowl, and do some work on the oil temp scoop.  I’m also going to vastly improve the TB air inlet that’s in the right radiator duct. 

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