Hi All Esqual and Lightning list members,
I must apologize for not getting this message out
sooner. I flew my Esqual LS (LS = Lightning Stuff ;-)) to Tennessee last
Thursday, 6 July, to fly the Lightning prototype (N233AL) and to help with
writing the pilot's operating flight manual. It has been a busy but, as
always, a fun time. My flight to Shelbyville was non stop in 3.6 hours,
averaging 154 mph block to block (had a small head wind most of the way).
Total statute miles is 554 and my fuel burn averaged 5.5 gallons per
hour. Not too bad.
When I arrived in the SYI area, Nick was airborne
in 233AL on a "combat air patrol" waiting on me, and needless to say he
immediately "was on me" and kept the "MIGS" at bay the rest of the way to "home
plate". It would have been nice to "play for a while" but after 3.6 hours
I needed to land ASAP - call of nature.
I flew the Lightning solo late Friday morning,
7 July, 2006, and had a great flight. Outside air temp for take off
was already 85 degrees. Most of my flight testing was done at 5,000 to
6,000 feet and the average OAT up there was 72 degrees. I should have
noted the density altitude, but failed to do so. Needless to say, it was
high. I topped off 233AL for the flight (22 gallons total) so I estimate a
take off weight of 1230. Remember, 233AL being a prototype is
probably 100 pounds heavier than production kit Lightnings.
Take off in the Lightning was short and
quick. At Shelbyville's field elevation of 800 feet and 85 degrees, the
Lightning was airborne in approximately 500 feet. Runway lights helped me
to estimate this distance. I used 10 degrees of flaps for takeoff and
after rotation I raised the flaps when accelerating through 75 and then
used 87 mph (Vx) for my initial climb. Passing the end of Runway
18, I started a left turn and let the nose down slightly to let the speed climb
to 100 mph which is Vy. Initial rate of climb was 1200 feet per
minute as shown on the VVI and when I got to 5500 feet it was showing
800 fpm. Total time to 5500 feet was 5 minutes. That averages
1000 fpm in my book. Not bad for a hot day.
After a few quick clearing turns to check the
area (no MIGS) and to get the feel for the airplane, I started doing some clean
and dirty stalls. The airplane flies with the ball centered with no
tendency to roll when trimmed hands off. However, I did notice that the
right aileron is up about 1/2 inch in straight and level flight. Overall I
did a total of ten stalls each, clean and dirty, to make sure I had
those numbers accurately documented. Clean stalls, as in the Esqual, are
quite nose high, but the nose drop, when it comes, is not violent at all.
There is a slight buffet, then the nose slowly drops. There was a tendency
for the left wing to drop which was easily corrected with rudder. My
assumption is that the left wing low was due to me sitting on the left
side. The clean stall occurred at between 48 and 50 mph.
Remember, I was not at the 1425 gross weight or the 1320 gross weight for the
Lightning Sport Plane. Flaps down stalls occurred at 34 to 36
mph. (Note: These airspeed numbers are from the EFIS now installed
in the Lightning. We already knew that the Lightning's standard "round dial
airspeed" reads low when at the slower speeds. The EFIS in 233AL
reads exactly what 31BZ's EFIS and back up airspeed read when the two
airplanes are in formation.)
The Lightning's flaps go down a full 45 degrees as
opposed to the Esqual's 30 degrees full flaps. I did some of the flap down
stalls at 45 degrees and some at 30 degrees just to get a comparison. I
really didn't note any difference in stall speed, but there is a big difference
in drag. Meaning the speed drops much quicker at 45 degrees and when you
power back up to recover it takes much longer to get a climb going. This
could possibly be a problem on a last minute go around with 45 degrees of
flaps - 30 degrees is much better in my estimation. Just a
thought, but Lightning builders might consider changing the flap
actuation system to only go down 30 degrees. Any way, the dirty
stalls were not nearly as nose high, the slight buffet was there to "talk to
you", and the nose fall was gentle. The tendency for the left wing to fall
off was much less.
With the stall series out of the way, I could
now play with the Lightning to better evaluate how it performs. One
maneuver I like to do when evaluating aerobatic biplanes, is to put it in a 3 G
level turn at some airspeed to see if the speed falls off quickly, stays the
same, or perhaps increases. This is my way to see how quickly an airplane
bleeds energy or to measure any excess energy. An interesting thing
happened with the Lightning while doing this maneuver. At 2900 rpm and 120
mph, in a 3 G continuous level turn, the Lightning just keeps on holding 120 and
pulling 3 Gs. Pretty impressive. But what is more impressive is that
if you push the power up the Lightning accelerates while still pulling 3
Gs. No energy bleed here - definitely excess energy. The wing makes
the difference.
Speed runs at 5000' were about what I expected
based on what Nick had briefed me on. His initial flight test for
performance data was done with a Sensenich 64ZK54 (54 inch pitch prop) and were
done during this past winter and spring. At that time he was seeing 175
true mph at only about 3050 rpm, and close to 190 when at full throttle - but
was pulling the throttle back to keep below the 3300 max rpm. Now, using
the new carbon fiber ground adjustable Sensenich, he is still experimenting with
the correct blade setting for optimum speed performance. Add to that the
really hot high density altitude and the speed numbers are lower than a
Lightning builder can expect with the correct prop setting. Here are the
numbers I saw: 2850 = 150 true mph, 2950 = 157, 3050 = 165, 3150 = 170,
and 3250 = 177. There is no doubt in my mind, that the correct pitch prop
on a standard day will increase all of these numbers by at least 10 mph,
probably more.
I like the
way the Lightning flies more than I like how my Esqual flies (and I
really like 31BZ). Here are the main differences that I noted (and these
differences showed up again in a later formation flight). The Lightning
accelerates slightly faster and decelerates slower than 31BZ. The
different wing (shorter and different airfoil - a NACA 6200 series) has less
drag than the longer Esqual wing. This shorter wing also results in a
smoother ride when down low in turbulence. Pitch forces are light in
both aircraft, but slightly lighter in 31BZ (which is a lighter airplane).
Roll forces are slightly less in the Lightning (shorter wing). Roll rate
is hard to accurately measure, so I will just go on my past experiences and say
that it rolls faster than a Cessna or Piper, and slower than the RV series of
aircraft. I have only flown the RV-3 (I did the stall and spin test for a
friend) and it was a great airplane. Roll is waymuch slower than my
Pitts, but then most everything is, expect the fighters I flew in the Air
Force. I would estimate roll rate at about 120 degrees per second, but
then I could be off. What ever it is, it is nice. Pitch and roll
forces are well harmonized at 120 mph and below. However, as speed
increases, pitch forces only slightly increase while roll forces go up a
lot - just like most high aspect ratio aircraft with relatively small
ailerons. From what I remember of my RV-3 time, as speed increased, roll
forces stayed light, but pitch forces went up a lot. Again the different
wing design (smaller span with larger ailerons) would cause this. Bottom
line, the Lightning is a delight to fly. A sporty feel with very spirited
performance while being very economical to operate. Wow!
Landings are actually easier than the Esqual in
that the Lightning wing seems to "groove" more, meaning that wind gusts and
turbulence have less effect on the Lightning. I made three landings, two
using 30 degrees of flaps and one with 45 degrees. You can fly a steeper
approach with the high drag that the 45 degrees gives you, but I feel that the
30 degree flap setting is a better choice based on my comments above about go
arounds. Touch downs are easy and there is not much float if your airspeed
is on target. I used 60 mph on final in the Lightning and I always try for
a full stall landing. Once on the ground it rolls out straight and you can
easily make a 1000 foot turn off. If you want to use lots of brakes,
you can stop much shorter. Piece of cake.
Friday afternoon Nick and I flew a close
(fingertip) formation flight to gather some additional data to use in developing
the performance charts. N31BZ is equipped with fuel flow and manifold
pressure (233AL, being a prototype does not have this equipment) and we needed
this information to more accurately predict cruise and range data. I had a
copilot with me to write down all the data, so all Nick and I had to do was
accurately fly specific speeds in close formation. At various speeds we
wrote down rpm, IAS, TAS, FF and MAP. Later we could compare these
numbers and more accurately predict 233AL's fuel flows and manifold
pressures. The results are now in the Lightning's flight manual.
I will close with a bit of good news for those of
you that want to build a light sport compliant Lightning. Nick and I have
figured out a way for you to have the neat gear leg fairings and the latest
style low drag wheel pants. All you have to do is install a drag
chute. The Lightning is really going to be that fast.......and
economical too. What could be better than that!
Blue Skies,
Buz
PS: I am now back home in Virginia to get ready to fly 31BZ to
OSH. The nonstop flight home (554 miles) with a slight tailwind took 3+17
and burned 18.5 gallons. Block to block speed was 168 mph burning an
average of 5.6 gallons per hour. Pretty good! While in SYI, I also
got the chance to fly their new Jabiru 400 (a real 172 beater in every aspect)
and their Jabiru 170 trainer (the cute one). Look for both of these, along
with the prototype Lightning at OSH. Hope to see all of you there.
We need to plan a get together to talk Lightnings and Esquals. Someone
have a suggestion? I will get there about a week early to work in the
Vintage area, so anytime is OK with me.