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1. 04:42 PM - Lightning Flight review (N1BZRich@aol.com)
2. 05:32 PM - Re: Lightning Flight review (Rick Bowen)
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| Subject: | Lightning Flight review |
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.
Message 2
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| Subject: | Lightning Flight review |
--> Lightning-List message posted by: "Rick Bowen" <rollnloop@hotmail.com>
Buz,
EXCELLENT read of your flight review!
Thank you for taking the time to gather the data, and then write it up, and
post it here.
Looking forward to getting a membership in the "Lightning Club"...!
So, is Nick planning on supplying the SP "required" drag chute to go with
the gear leg fairing kit????
8-)
Just a interesting side note: Did you hear they just gave the Joint-Strike
Fighter it's official name? Honest, it is going to be called the....
"Lightning II"
Rick
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