The Legacy of Martin Hollmann

kolibri282

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It has gone, a bit to my surprise, without much notice that Martin Hollmann has left us. I had phoned Martin almost thirty years ago when I bought my first book on rotary wing aircraft: "Modern Gyroplane Design". I found him to be a very amiable and helpful man who had no qualms about talking to a "Know Nothing Novice" in the area. His book gave me the impression that it might be possible, with a German degree in engineering as a background, to work my way into gyro theory to the point where I could perhaps one day come up with a design of my own. That got me started.
With a bit more experience in numerical methods I found that his rotor blade program has a major flaw of which I will be glad to inform you if you are interested in the topic.
About a year ago I came across an unprotected site where several of Martins reports are stored and I felt it would be inappropriate to publish these without permission.
Tonight I phoned Rita Costa-Hollmann and she confirmed that the reports should now be available to the general public.

So here is to a great designer and engineer:
a) Martin's Master Thesis: http://www.aircraftdesigns.com/media/system/pdf/hollmann_thesis.pdf
b) Martin's BumbleBee Design : http://www.aircraftdesigns.com/media/system/pdf/bumble_bee_analysis.pdf
c) Martin's Sportster Design: http://www.aircraftdesigns.com/media/system/pdf/sportster.pdf
 
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Murtster

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Wow!
That's what I call proper engineering - the kind that shows that Martin understood the engineering problems and not just use the tools...
(moment of nostalgia)

I am trying to learn all I can about Autogyro design (I have 20 years experience in fixed wing aircraft design).

I am considering to buy Martin Hollman's Modern Gyroplane Design 4th edition, but living in England, I can't get my hands on a copy - normally I like to have a little peek to see what I am buying.
I am a little concerned about forking out the $200 + S&H from the US and then finding it is not what I hoped for.

Can anyone comment? What does the book cover?

I am looking for data on weights/performance calculations/layout/geometry. I am comfortable with part-23 aircraft design, and there is a lot of good info out there (such as Roskam etc). What I am after is a 'Roskam' or 'Raymer' for autogyros.
 

fara

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Wow!
That's what I call proper engineering - the kind that shows that Martin understood the engineering problems and not just use the tools...
(moment of nostalgia)

I am trying to learn all I can about Autogyro design (I have 20 years experience in fixed wing aircraft design).

I am considering to buy Martin Hollman's Modern Gyroplane Design 4th edition, but living in England, I can't get my hands on a copy - normally I like to have a little peek to see what I am buying.
I am a little concerned about forking out the $200 + S&H from the US and then finding it is not what I hoped for.

Can anyone comment? What does the book cover?

I am looking for data on weights/performance calculations/layout/geometry. I am comfortable with part-23 aircraft design, and there is a lot of good info out there (such as Roskam etc). What I am after is a 'Roskam' or 'Raymer' for autogyros.
Martin:
Mr. Hollman's book is worth the money. The programs however are in 32 bit and will not run on Windows 7 unless you have "Ultimate" which allows running 32 bit applications as well. I am trying to see if Mr. Hollman's family will let me have the code so I can compile it for 64 bit possibly in a different language. There are indeed some small mistakes that some people pointed out (and they seem to be correct) like analysis of the rotor bending loads but there is a NACA report that he supposedly took that idea from and you can simply refer to that to get proper results (its available). Other mistakes are minor and overall its worth the read. It will however not be a miracle book but with your said experience you should be able to make sense of it IMO.
 

scandtours

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Wow!
I am considering to buy Martin Hollman's Modern Gyroplane Design 4th edition, but living in England, I can't get my hands on a copy - normally I like to have a little peek to see what I am buying.
I am a little concerned about forking out the $200 + S&H from the US and then finding it is not what I hoped for.
Can anyone comment? What does the book cover?
I.
As per Martin Hollmann preface....Althought over 90 percent of the information in this book applies to all gyroplanes, it should be remembered that most of the information presented herein has been gained from Sportster gyroplane.

I remember I bought this book in 1980 and in 1986 also the book"" Flying The Gyroplane."" For both books the price for that time was round $40.00.
 

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kolibri282

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Martin,

please note that it is very easy to rewrite those programs in octave (which is a free Matlab clone). If you want to get an idea have a look here:
http://www.rotaryforum.com/forum/showpost.php?p=514825&postcount=4

I have collected several links to postings regarding jump start, a topic that is also covered in Martin Hollman's book. One of the links is to my own octave implementation of the original naca jump start report. octave works without problems on win7

Another program that might be of interest is a gyro performance program similar to Martin Hollman's that was proposed by Russian designer P.I. Bratuchin. An octave implementation based on the rotor formulae of naca-716 is available here:
http://www.rotaryforum.com/forum/showthread.php?t=28419

A translation of almost the whole of Bratuchins book is here:
http://twistairclub.narod.ru/bratgyro/complete.zip
 
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Vance

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A short note about Martin Hollmann.

A short note about Martin Hollmann.

I was fortunate to know him and enjoy his friendship for many years.

He did a structural and stability analysis on a tractor gyroplane project I was working on and in my opinion didn’t charge nearly enough. He didn’t like tail draggers but he did it because it was what I was interested in. He gave me more free time than I could take.

One of the last projects he worked on was the empennage for Mariah Gale.

He did the structural analysis and made elaborate hand drawn blueprints.

There are very complete materials and list and instructions for how to build it.

He threw in a structural analysis of the airframe to help protect Ed.

Again he did not charge enough for his time.

He also gave me several of his books over the years.

I feel fortunate to have known him.

We did not always agree but we always shared our love of aviation.

I think of him often and the many things he taught me.

He was considered by many to be a composite aircraft expert.

He used to flat tow (no trailer) his Sporster behind his VW to the various air shows.

For years he gave classes at aviation events.

I value his friendship as much as the things he taught me.

Thank you, Vance
 

skier

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Martin,

please note that it is very easy to rewrite those programs in octave (which is a free Matlab clone).
Have you tried running Octave on Windows 7. From what I read, it seemed like it may be a bit of a challenge to install it there since it was designed for Linux.
 

kolibri282

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Andy, windows versions have been available for quite some time and on win7 these work out of the box (thanks to gcc...;-)

What I am after is a 'Roskam' or 'Raymer' for autogyros
There is currently no book of that kind on gyro design but the "Roscam" for helicopters is in my opinion "Helicopter Flight Dynamics, Stability and Control" by Raymond Prouty. It has a worked out example which is used throughout the book.

As an introduction you might want to read naca 487:
http://www.gdt-systems.com/files/naca/naca-report-487.pdf

and naca 716:
http://soliton.ae.gatech.edu/people/lsankar/AE6070.Spring2004/bailey.nacareport.716.pdf

I have also added a link to Bratuchin's book mentioned in post #6, which is a good introduction as well.


The real problem with autogyros is calculating the stability derivatives.

PS: How on earth could I forget Harris' books:
http://www.rotaryforum.com/forum/showthread.php?t=32431
 
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scandtours

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Sometimes, I am wondering what’s the meaning/purpose of all these books to an average gyro pilots? ( For a simple equation see below.)
I am not sure but I believe is useless.
The purpose of those books is to relate proper design techniques and consideration necessary to design successful autogyros/aircraft for manufacturers. (Here I must say that I know only one who has aeronautical engineering degree and builds gyros) It most European countries it's a must to have aeronautical engineering degree in order to design and sell gyros.
For all aeronautical engineers, mec engineers and ph/scientists all those formulas are well known. For most gyro pilots this is like trying to translate a books from Chinese into any other language.
I must also say how much attention did the ancient Greeks paid to education (while most other people were still living in caves.)
....YOU SEE DOUBLE IF YOU ARE EDUCATED .... How right they were, thousands of years ago...
For a pilot flying few hundred ft above the ground every now and then or daily, those books will not help in anything.
 

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9aplus

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in short my professor explanation is:
"Calculation, even matrix like above, allows engineers
to make few mistakes less....."
Without that you are in trial and error area of engineering science,
that can take away some time, money and nerves.
 

kolibri282

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Sometimes, I am wondering what’s the meaning/purpose of all these books to a normal gyro pilots
I am not sure but I believe is useless
Only these equations allow to build safe and reliable aircraft, that's their significance for the average pilot. He does not need to know them - like someone switching on a TV set does not need to know Maxwells electromagnetic wave equation yet without the knowledge of this equation no TV set could be designed. Likewise progress in the design of rotary wing aircraft has been brought about by engineers who were able to build mathematical models to describe the behaviour of these aircraft. Only a mathematical model allows to separate the many interacting factors and decide which change is necessary to achieve a desired outcome.
Cierva, Bensen, Wheatley, Young you name them, were chaps who understood this and used the tools of the engineering trade to solve the problems they encountered. One brilliant example is the paper that explains the inverted control reaction of the C-30 due to excessive blade twist (naca-600: An analysis of the factors that determine the periodic twist of an autogiro rotor blade, with a comparison of predicted (sic!) and measured results)

As my professor for mechanical design has put it:"There is nothing half as practical as a good theory".

One last thought: there is a good reason why all test pilots today have a degree in aeronautical engineering: their knowledge of underlying theory allows them to analyze the behaviour of the aircraft they fly more profoundly. So while it is not necessary for the average pilot a thorough understanding of flight theory makes the difference between a good pilot and a test pilot.
 
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ckurz7000

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I just wanted to hit the keys in reply to Giorgos' post when I read Djani's and Jürgen's post. They say it all.

-- Chris.
 

scandtours

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Maybe I did not make myself understood.
I am not against education hence the statement (You see double if you have education.)
On the other hand, by reading Hollmanns book I don’t think that I have become a better pilot. Maybe it makes a better designed gyro......
 
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Vance

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I find knowledge expands my joy of flying.

I find knowledge expands my joy of flying.

Sometimes, I am wondering what’s the meaning/purpose of all these books to an average gyro pilots? ( For a simple equation see below.)

I am not sure but I believe is useless.
For a pilot flying few hundred ft above the ground every now and then or daily, those books will not help in anything.
I find my joy and freedom expands as I learn the fundamentals of how things work.

I find it helps to calibrate my BS indicator so some charlatan doesn’t mislead me.

I have a low fear threshold and knowledge helps me to exorcize the demons that live in the shadows of my mind.

I concur with the statement; knowledge is power and no knowledge is wasted!

I feel knowledge is not a substitute for wisdom.

Thank you, Vance
 

cbonnerup

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We will miss Mr. Hollmann for is contributions to aircraft (autogyro) engineering.
I wonder if his son Eric will get involved with the company?

Good comments all...
Chris
 

j bird

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Vance, for being brain compromised, I find your extraordinary wit on some of the subjects posted on the forum quite insightful. No need to comment on my post, just wanted to say how much I appreciate you being a part of the RotaryWing forum.
 

gyroplanes

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Martin Hollman factoid of interest

Martin Hollman factoid of interest

I met Martin at the PRA convention the year he flat towed his new Sportster to Rockford, IL.

I got to know and admire the Black Forest Giant. On day martin told me about a girl he used to hang around with, her name was Jeana.
Marty and Jeana used to visit an amateur rocket builder somewhere out in the desert.

Marty said he introduced Jeana to another friend of his, Dick Rutan. Jeana and Dick became close, very close. So close the two of them occupied a very small cockpit and flew around-the-world together, un-refueled.

I do believe they parted after that flight.

In the 70's I was running a Cessna dealership shop near Chicago. Early one morning a bright young lady came in inquiring about renting a Grumman. I noticed a Varieze lapel pin on her jacket and made comment. She said, my boyfriend's brother designed it. I said "Jeana, Jeana Yeager?" We shared some laughs about the gentle giant, Marty Hollman. (Jeana was visiting relatives in the area)
 

Jean Claude

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Can anyone tell me the origin of this figure used in "Martin's BumbleBee Design "?
Thank you.

 
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