Why did the American Helicopter Society not print this 'Letter to the Editor'?

[Dave_Jackson]

The following 'Letter to the Editor" was submitted to Vertiflite, the American Helicopter Society's quarterly publication, on May 16, 2006. A follow-up was sent on Dec 7, 2006. There have been no acknowledgments, nor has the letter been printed. However, they did print a simplistic 'helicopter in every garage' letter of mine in the Summer 2002 issue.

Speculation as to why this letter was not printed will be appreciated.

Dave

http://www.unicopter.com/GreenAndBlackStripe.gif

Lateral Symmetry

Charles Darwin to Intelligent Design


Symmetry has an aesthetic beauty, but more importantly, it has a functional beauty. Virtually all mobile life forms are laterally symmetrical. The fish in the ocean, the animals on the land and the birds in the air all share this characteristic. The logic of this 'survival of the fittest' is unquestionable. In addition, man's technological developments are founded in nature. It is therefore not coincidental that all vehicles are laterally symmetrical. All that is, except for a very few temporal exceptions; such as helicopters with tail-rotors, with tandem-rotors and even those with coaxial-rotors.

How did this anomaly come about? At the dawn of helicopter flight, the leading country in this field was Germany. It developed effective craft using laterally symmetrical configurations. In fact, the Intermeshing Flettner FL-282 and the Side-by-side Focke Fa-223 were the world's first production helicopters. The Flettner FL-282 was comparable to the Sikorsky R-4B, but it out performed the R-4B in all primary areas. In fact, it was said "At an AHS dinner meeting where Flettner and Sikorsky were both present, Igor was taken aback by the technological advancements shown in an 8mm film of the Intermeshing Flettner FL-282."

What went so wrong and why has there been sixty years of tail-rotor dominance? At the risk of irritating some, I suggest that the Germans, plus the Russians and the Europeans lost the Second World War, economically, whereas the United States was the major winner. The ideas that were prevalent in the United States at that time became the predominant configuration. The majority and the financially endowed went with the single rotor, and 'simply' offset its torque with a horizontal fan. I suspect that the problems confronting the rotor aerodynamists were formidable and the early American developers resisted compounding these problems by having to deal with two main rotors. Unfortunately, this configuration with a tail rotor created a new set of problems that can never be adequately overcome. In addition, the early Western aerodynamicists appear to have underestimated the thrust-to-power advantage of twin main rotors.

If the expertise and money, which was devoted to the fan-on-tail helicopters, had been applied to improving the twin-rotor configurations, I suspect that some of the current concerns of the V-22 would now be little more than historical footnotes. This sixty years of wandering in the wilderness should have been spent improving the lift/drag ratio of the rotor by developing features such as, active blade twist and high-rate pitch change.

Volume production is the primary means of cost reduction. A craft with twin main rotors becomes an ironic means of halving the research and development costs and significantly reducing the production costs, per blade.

The Tilt-rotor configuration probably represents the first salvo in the evolution of Generation II Rotorcraft. A revived and improved Coaxial-ABC may represent the second salvo. However IMHO, the greatest salvo will be the modern Intermeshing and Interleaving configurations that are founded in intelligent design.

[helopat]

I'm not disagreeing with ANY of your points (as a matter of fact, I think the US actually DID win WWII, not just economically...ahhhh, jeez, strike that...don't want to get off on the wrong foot).

I think part of the problem is that most magazines are just not interested in a letter to the editor that takes up the first three pages of the magazine (remembering that they print in columns and that adverts are also an integral part of the magazine).

The other thing is, whats your point? The lateral symetry thing is 'interesting', but at this point in helicopter histoiry what do you expect to do...start a revolution and revert to tandem rotors? As I said, your points are valid, but (and I mean this in all seriousness) this is more the kind of thing I'd expect to see as the Foreward in a book about helo design history, not what I'd want to read in a rotary wing periodical.

I hope this doesn't come across as a dig, because you are obviously passionate about this.

HP

[slowrotor]

I think Charles Darwin would have said, "The fittest will survive with or without symmetry."

Dave, almost all airplanes lack symmetry. Burt Rutan built an obviously unsymmetrical airplane to prove the point. It was called Boomerang.

Your letter does not address how a low cost VTOL could be developed. And your love of symmetry spoils any other ideas in your letters.

Sometimes we fall in love with our pet ideas. This forum can help you get another view.
If you are sure of your view, then stick with it. But don't expect an editor to respond.

[IFMU]

When the US & its allies won the war, they hardly buried German technology. There was a great infusion of German technology into America, including Von Braun with his masterpiece that brought us to the moon. Some of their great engineers, and test pilots became Americans and contributed for many years. I would say that synchrocopters did not come to dominate because they didn't make the cut.

-- IFMU

[Jack Carson]

I agree with IFMU. One has to only look to some of the attempts at what we may now term non traditional designs. The Russian MI-12 “Homer” was a spectacular performer with a max all up weight exceeding 100 tonnes. Charlie Kaman’s, Husky and K-Max, had only limited success performing very specific missions. However, both companies had considerable success with their more traditionally designed machines. My experience with having flown Sikorsky's XH-59 makes me tend to believe that future helicopter designs will include very capable light to medium weight rigid coax machines. Like the Kamov there are reasonable size and weight limits associated with this design.

[Graviman]

IFMU, i'm also with you on that comment. Interestingly, the debate still rages to this day about whether rockets would have happened if hypersonic space planes had continued development...

In addition, man's technological developments are founded in nature.

Dave, where in nature do wheels travel on steel rails? Nature can give useful pointers, but normally it seems to be a question of recognising technological aspects in the natural world. My own thoughts are that you need the maths, physics, and the engineering to make a technology work.

My experience with having flown Sikorsky's XH-59 makes me tend to believe that future helicopter designs will include very capable light to medium weight rigid coax machines.

Agreed with this, Jack. If there was a downside to this is would be the packaging required for cyclic control blade twist - likely to be the next rotorcraft step.

Mart

[Rich Lee]

Rather than 'speculate' the reason this submission was not published on Pprune, perhaps you might obtain a more informative response if you sent an inquirie to Kim Smith ( [email protected]) the editor of Vertiflight or Rhett Flater the publisher at the same email address.

A technical article supporting your theory rather than a socio-political commentary would be more aligned with Vertiflite's stated "editorial energies that are devoted to informing our readers of the advances being made in the industry and encouraging increasingly broader use of rotorcraft."

.

[Dave_Jackson]

Thank you for the diverse and the valid comments.

_________________________________


Helopat:
"what do you expect to do...start a revolution and revert to tandem rotors?"
Yup, and the twin-rotor revolution has begun. ;)
First with Bell's tiltrotor and now with Sikorsky's coaxials.

IFMU;
Von Braun and his boys were brought in to work in a virgin field. Rotorcraft already had its proponents, with their own ideas.

Jack Carson;
This may answer some historical questions and concerns. (http://www.unicopter.com/B280.html)

Graviman:
If the Egyptians had used unsymmetrical logs they would still be rolling their block around, and around, trying to build a pyramid. :)

Rich Lee:
The provocative, but factual, letter was initially set to Kim Smith at [email protected]. The follow up was sent directly to [email protected].

Slowrotor:
The 'Vertiflite' publication has a circulation of 5,000. The letter is intentionally provocative, but it is factual. Its purpose was to cause a small segment of the readership to 'think outside the box'. To contemplate a third, and IMO a superior, means of taking rotorcraft beyond the tail-rotor and into Generation II.


Without provocation, how many companies or people have the incentive look outside their box?
http://www.unicopter.com/Eyeflash.gif :)



Dave

[slowrotor]

What the aeronautics community in the United
States lacks is a champion with common sense
like “Dave.” In the meantime, we will always
have “February.”

Quote from Vertiflight spring 2005 page 8 shown here at : http://www.vtol.org/pdf/commentaryspring05.pdf

[IFMU]

IFMU;
Von Braun and his boys were brought in to work in a virgin field. Rotorcraft already had its proponents, with their own ideas.
Not entirely virgin. We had Robert Goddard. Of Goddard, Von Braun said:

"His rockets ... may have been rather crude by present-day standards, but they blazed the trail and incorporated many features used in our most modern rockets and space vehicles"

Ironically, it would seem that Nazi Germany took more interest in Goddard's work than our own country at the time.

-- IFMU