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Marv - could you please post the new flutter reply from me as
shown below. I made some corrections and improvements. Thanks.
M.Hollmann
Dear Aviators,
I have been ambushed by someone who does not have the courage put his
name on what he claims. We will call him Mr. X. After reading what Mr.
X wrote, I can see why he wants to hide. All of his statements are lies.
Since Mr. X worked for Lancair and his statements are about the Lancair
aircraft, I should introduce myself first. My name is Martin Hollmann and
I did most of the structural design and performed all of the stress
analysis on all of the Lancair series of homebuilt aircraft. This
includes the Lancair 200, 325, 320, 360, L-IV, and ES. The FAA
designation for the Lancair 360 is LC20. I prefer the factory
designation. These aircraft are some of the best kits on the market and
none of these aircraft have ever had an inflight structural problem. I
and Lance and all of the Lancair pilots and their families are very proud
and happy about this.
Mr. X works for Scale Technology Works (STW) which is a sister company to
Scale Composites and he has worked for Lancair. He makes a number of
false statements which I would like to clarify.
His first statement "Martin contracted Sam McIntosh to show him how to do
flutter analysis on the Lancair IV" is false. During the design phase of
the Lancair IV, I told Lance that we had to do a flutter analysis on the
L-IV. I contacted Sam and after talking to Sam for half a year I got his
price down $28,000. This was too high for Lance. So I asked Sam if I
would perform the finite element analysis (fea) and he would perform the
flutter analysis what his price would be. He stated $12,000. The next
day, I told Lance that I would perform the fea at a cost of $3,000 for a
total of $15,000. for a complete flutter analysis. He agreed and we did
the analysis. At this time I was working on a military program and was
able to obtain the source code for the FASTEX program from the Flight
Dynamics Laboratory. To check the answers that Sam had come up with, I
(with the help of others) converted the flutter part of the FASTEX
program to run on a PC and I used this program and the help of the Flight
Dynamics Lab at Wright Patt AFB. They were a big help to me. We all came
up with the same answer. I was responsible for the complete analysis of
the L-IV and there was no room for error. Not at the speeds that this
aircraft flys. I gave Sam my flutter program which I called SAF and Sam
purchased the NISA fea program from me since I was a dealer for this
program. I also invited Sam with me when I performed the ground vibration
test (gvt) on the L-IV. "Sam did not show me how to do a flutter
analysis." He is much too protective of his trade for that.
I had spent 3 years on my Master thesis design rotor blades for
helicopters. I performed a flutter analysis and a gvt on the rotor
blades I built for my Sportster. I also learned to perform fea while
working at Ford Aerospace, Lockheed, FMC, and finally at Kaiser
Electronics were I performed random vibration analysis on head up display
systems for the F-14, F-18, F-15 and many other aircraft. This was way
before I helped Lance on the L-IV.
Most of the homebuilders cannot afford a flutter analysis and as such I
have tried to make it affordable. This is important since many accidents
occur each year because of flutter. In fact it is so important that I
have given a number of classes on this subject and I am the only one at
Oshkosh to hold a forum on flutter. I have also written a book titled
"Modern Aerodynamic Flutter Analysis" and I sell my SAF program at a very
reasonlable price. See my web site at
<<http://www.aircraftdesigns.com>www.aircraftdesigns.com. Unfortunately,
in many cases I have performed a post crash flutter analysis in which the
flutter problem and lose of life and aircraft could have been prevented.
I performed the initial flutter analysis on the ES at no charge. When I
performed the flutter analysis on the Stallion wing using fiberglass I
found a low critical flutter speed. As such I used graphite which is
stronger and stiffer than fiberglass and it gave me a higher critical
flutter speed for my Stallion. I also contacted Lance and told him of
the low flutter speed. Lance did not want to believe me so I told him to
contact someone else other than me. I told him to have Sam perform an
analysis. Sam's results were never made public nor were the analysis
performed by others. As such I do not know if Sam came up with the same
results.
Now in the light of this fact, if we review Mr. X's statement that "Sam
McIntosh did the flutter analysis, (on the ES) using codes similar to the
ones Martin uses. I think this pissed off the always arrogant Martin and
he took it upon himself to slam any analysis done by an outsider."
I never slammed Sam's work. Infact I had asked Lance to go to Sam. I
also never saw the results and as such there is no way that I could slam
Sam's work. This accusation is insulting and simply not true.
Now for more insults from Mr. X at STW. He states that "Some builders
were modifying the 360 aircraft and contracted Martin to do the flutter
analysis. Martin found problems and wanted Lancair to pay for him to do
more analysis." Lance never contracted me to do the flutter analysis on
the 360, the builders did and they chiped in to pay me. We did this
because some of the builders were using large engines and flying at
cruise speeds over 220 kts. We also did this because a number of major
mods had been perfomed on the 360 such as the addition of a bigger
horizontal tail and a longer wings. A flutter analysis had not been
performed on any of the Lancair 320 or 360 models. It was a prudent
decision and good judgement to perform the flutter analysis since we now
know what the critical flutter speeds are for these aircraft with the
different mods. It has always been my goal and it will remain my goal to
provide technical support to all aircraft builders and pilots. I will
not let someone like Mr. X discourage me from helping others to fly
safely.
The last statement that Mr. X posted that makes me suspicious of his
qualifications is, "I believe the 360s are safe in regards to flutter if
built according to plan." Safe from flutter is only relative to speed,
altitude, fuel loading, gross weight. If you point the nose down and
apply full power you can easily exceed the flutter speed of the 360, or
for that matter, most other aircraft. It is important to know what the
never exceed speed is for your aircraft based on flutter and structural
reasons and then not to exceed that speed. Why not ask Mr. X what the
critical flutter speeds are for the Lancair or anyother aircraft your are
flying.
Last but not least, the H7WC doublet lattice program I use in my flutter
program has been used by most major aerospace companies such as Boeing,
Northrup, Lockheed, NASA, and McDonnel Douglas. It is one of the very
few standards in the industry. I have been performing flutter analysis
now for 25 years and my flutter predictions have always been correct.
I would like to invite each one of you to attend my flutter forum at
Oshkosh. See my web site for date and time under News. If you have any
questions on flutter please call me any time at 831-649-6212. Then make
up your mind on who you want to believe. God bless.
Martin Hollmann
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