Date: Wed, 17 Mar 1999 20:05:18 -0800
From: "Aircraft Designs, Inc." <aircraftdesigns@cwix.com>
Subject: Flutter
To: lancair.list@olsusa.com
Message-id: <002201be70f4$8ac5c2e0$2b0737a6@oemcomputer>
Mime-Version: 1.0

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Dear Aviators,

I have been abused by someone who does not have the courage to state =

his name.  This person 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 clearify. 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 NASA. =

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. 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. "Sam did =

not teach me how to perform a flutter analysis."


I had spent 3 years on my Master thesis design rotor blades for =

helicopters.  I performed a flutter analysis and a ground vibration test =

(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 where 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 this subject. I have also =

written a book on the subject and I sell my SAF program at a very =

reasonlable price.  See my web site at www.aircraftdesigns.com. =


Unfortunately, in many cases I have performed a post crash flutter =

analysis in which the flutter problem 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 very low critical flutter speed.  As such I used graphite which =

is stronger and stiffer than fiberglass.  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 my =

analysis varified by Sam which he did.  Sam's results were never made =

public nor were any of the other analysis performed by others.


Now for another wopper from Mr. X at STW.  He states that "Some builders =

were modifying the 360 aircraft and contracted Martin to do the flutter =

analysis."  Lance never contracted me to do the flutter analysis on the =

360, the builders did and they chipped 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 a bigger tail and a bigger wing.  =

It was a prudent and good decision since we now know what the critical =

flutter speeds are for this aircraft with the different mods.


The last statement that Mr. X makes 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.


Last but not least, the flutter method I use and the computer program I =

own and sell is 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 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