REFLECTOR: N647JA Flys!

[Bachman, Jonathan]

Congratulations!

Jon Bachman
N956DR Std RG KALM

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Scott Derrick
Sent: Monday, September 28, 2009 8:51 AM
To: Velocity Aircraft Owners and Builders list
Subject: REFLECTOR: N647JA Flys!

Flew for 30 minutes yesterday!  After 3 years of off and on again work.

I've decided that the aircraft magneto, performance wise, is a POS,  yes
they are reasonably reliable and don't require external power but you
sure sacrifice a lot for those two items.  But thats another story.

Took off at 11:30, it was 80 degrees, about 14 knots of wind favoring
31. Density altitude about 9,000 ft.  I had made a few run ups during
the morning timing a new mag and adjusting the mixture.  The engine was
moderately heat soaked from the run ups and extra long taxi & take off
check list..  Take off roll is still anemic, static at  about 2000 rpm, 
at rotation rpm was 2150.   Left the gear down until I had 750 ft agl
climbing at 90knots about 700 fpm.  It sounded and felt so weird!  I was
hypersensitive to any fluctuation or what I considered abnormal sounds
and there were many! :-)  Engine was fairly steady with a 10-20 rpm
oscillation  in the climb.   Finally brought up the gear and got that
surge of speed that is so characteristic of the Velocity.   oil and cyl
temps were climbing so let the nose down  and settled into a  120 knot
climb at about 1,000 fpm. I then pushed the mixture in to full rich to
see if that would slow the temp rise.  Oil was at 210, hottest cyl at
about 380.  Stopped the climb at 8,500 asl and pulled the throttle back
to keep the speed at 130 kias, i was turning 2200 rpm at this speed,
that was my target airspeed for this first flight. temps still rising
though slower than before. Elevator trim was not working correctly. I
had installed the new trim system approximating the center position of
the elevator and obviously got it wrong, I had to hold considerable
forward stick pressure to maintain level flight even with full down
trim.  By now I had made a couple circuits of the airport 1,000 ft above
pattern altitude staying within a couple miles of the airport.  Temps
still rising oil at 230, hottest cyl at 420.  I made one more circuit
and decided that with the trim problem making it near impossible to
release the stick for more than a second at a time and the temps
leveling off now at just below redline for the oil and #1&2 cylinder
heads, it was time to land.  Made an extended downwind to provide me
with about a 4 mile final and put the gear down, pulled the throttle. 
Cylinder temps started a downward trend but the oil still stayed at
about 230.  Crossed the threshhold at 80 knots and made one of my better
landings at about 70 knots.  Let her roll for awhile and then taxied
back to the hanger.

All in all a good first flight. 

I remounted the trim actuator to provide much more down trim.  We'll see
if thats the correct spot.  With just me I am at the CG that requires
the more down trim, but I wasn't anywhere near top cruise speed which
requires  maximum down trim.

The high temps are my top priority. 

1.) I think I may be running lean.   #1 & #2 cylinder had EGT's in the
1450 range +- 25 degrees.  That was a full rich mixture which is not
consistent with the EGT's of the other 520's I fly.   Full  rich EGT's
should be  in the  1200-1300  range.

2.) I pulled the engine log for the flight(man I love that Dynon!) and
the CHT's are in a direct correlation with the EGT's.  #1&2 were the
hottest cylinders by 75 degrees and they also were the hottest EGT's by
over 100 degrees .  #3 was next hottest with a similar CHT-EGT
correlation.  I didn't have time to map out the peak temps which will be
next if the trim system will let me take my hand off the stick!  Maybe
cylinders 1-3  are just running to lean for some reason?

3.)  I know my plenum is not a really tight fit and that needs to be
addressed also. 

4.) I have read that running an incorrect heat range plug can effect
cylinder temps?  Anybody have advice about that?  Though 3 of the
cylinders had  perfectly normal EGT-CHT  temperatures?

Scott