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Bendix Helicopters Model K "Whirlaway"

Stargazer2006

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After the experimental Models G and H, Bendix Helicopters, Inc. had a go at finding their place on the market of small-size helicopters with the Models J and K, which both received the name Whirlaway. Unfortunately Hiller had already invested the segment of coaxial rotorcraft, and there seemed to be nothing that Bell's Model 47 couldn't do...

The Model J got a new lease on life as the Gyrodyne GCA-2 Helidyne, but Bendix's efforts at doing helicopters is largely forgotten (not to mention their stint at doing general aircraft...).
 

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walter

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Hi Stéphane :D
Thanks for the very nice pictures of the Bendix K. The caption under photo 1 mentions first prototype. I think that behind the rotor mast the registration is visible ..1817.
The registration on the covered aircraft is NX41817. Can it be that there was only one prototype of the Model K or is a second registration known, or even pictures?
Just asking out of curiosity. Please keep posting all these nice pictures!
 

Stargazer2006

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walter said:
I think that behind the rotor mast the registration is visible ..1817.
Actually it can be seen in its entirety. Look at the detail attached below.

I too was puzzled by the caption "first prototype." Probably wishful thinking on the part of Bendix's P.R. department...
 

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walter

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Thank you Stéphane for the detailed photo :)
In my notes (collected over many years, much during the pre-PC era) it says the FIRST prototype had a C85 egine and later received the egg shaped fuselage. Prototype TWO had a Continental C100 and the enclosed fuselage from the outset. One Model K was reportedly used for full-scale NACA wind tunnel tests.
Does this ring a bell? or should I file in the shoe-box marked "nonsense" and stick to ONE prototype only
 

Stargazer2006

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walter said:
Thank you Stéphane for the detailed photo :)
In my notes (collected over many years, much during the pre-PC era) it says the FIRST prototype had a C85 egine and later received the egg shaped fuselage. Prototype TWO had a Continental C100 and the enclosed fuselage from the outset. One Model K was reportedly used for full-scale NACA wind tunnel tests.
Does this ring a bell? or should I file in the shoe-box marked "nonsense" and stick to ONE prototype only
Interesting. I think that the fact we now have two sources that both mention TWO prototypes should make us wary. The fact that no photo of the second prototype has surfaced so far doesn't mean it didn't exist! Until there is a complete N-register for the post-war years available somewhere, it will have to remain in the "likely but unverified" box...
 

Stargazer2006

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Also, the Model J was also the Whirlaway. In a 1947 issue of Aviation Week, one can read that "Two helicopters of this model have already been test-flown and others are in the advanced stages of construction." It is possible that the "others" were of the "K" type, hence more than one. Just a hypothesis.
 

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Stargazer2006

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Sorry for answering my own posts, but I went looking for more information on the web and came across three interesting mentions, including one photo:

This is the Bendix Model K, an experimental helicopter that employed counter-rotating main rotor blades. Notice there is no tail rotor; the counter-rotating blades made it unnecessary. These helicopters were manufactured from 1945 until 1949 but never achieved certification. Bendix had hoped to develop a helicopter suitable for family use. Clearly, the idea never came to fruition.
Source: South Plainfield, by Richard F. Veit


The Bendix Model K, one-man experimental helicopter, shown in flight without body. The K has served as a test model for the four-place Model J planned for commercial use. The K has made flights up to 30 feet altitude and has a speed of 25 mph. It is powered by a 100 hp Continental engine and features dual co-axially mounted rotors.
Source: Aviation news - Volume 6 - Page 9


AT THE Wright Brothers commemoration the helicopter paid homage to the invention of the airplane. A Bendix Model K was flown at Kitty Hawk along the same course and at approximately the same altitude as was flown by the Wrights in their historic trip.
Source: Aero digest - Volume 56 - Page 54

So after reading these items, I think we can safely say that there MUST have been more than one Model K ("These helicopters", "a 100 hp Continental engine", "a Bendix Model K").
 

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walter

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What great finds Stéphane ! Need some time to let all sink in.
Could you agree with following (theory):
The Bendix J with registration NX74102 is in many pics. The registration NX74101 is seen on the Gyrodyne GC-2A and since that was evolved (modified) from the Bendix J, I think there were at least two Bendix J prototypes.
Bendix K with registration NX41817 was first flown with skeleton fuselage. Then received the egg-shaped covering, but still with open cockpit. The photo you found could show the second prototype since it seems to have a very different colour scheme and a closed forward cabin section. So NX41817 was prototype No.1 (C85 engine) and your photo depicts prototype 2 (C100 engine).
Any further ideas?
 

Stargazer2006

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I agree with all that you just wrote. I came to the same conclusions myself... ;)
 

cluttonfred

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That Bendix Model K is elegantly simple and would have been able to maneuver in small spaces, too bad it never made it past the prototype stage.
 

Mark Nankivil

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...and this appears to be the 4 seat Model J...

Also courtesy of the Gerald Balzer Collection.

Enjoy the Day! Mark
 

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walter

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Hi Mark :'(
Can you please stick to the forum rules? Stéphane and I had concluded what the history of the Bendix K was. Now you destroy our expertise by posting an egg-shaped NX41817. Completely unacceptable!!


BTW, great find that photo. Giant step to finally get to the whole (and factually correct) history :) .
 

Stargazer2006

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walter said:
Now you destroy our expertise by posting an egg-shaped NX41817. Completely unacceptable!!
Ditto!! :(

Now seriously... ;D Great find, Mark! So there probably only was ONE Bendix Model K prototype...
 

Mark Nankivil

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Well now, I guess you can move on to whether there was only one Model "J" then ;D

Enjoy the Day! Mark
 

hesham

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Hi,

http://archive.aviationweek.com/image/spread/19450108/9/2
 

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Mark Nankivil

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And from the same issue, artwork for what appears to be the Bendix Model J. Check out who the artist was....

Enjoy the Day! Mark
 

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Stargazer2006

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Mark Nankivil said:
Well now, I guess you can move on to whether there was only one Model "J" then ;D
Aerofiles identifies the Model J as [NX74101], although this clearly was the registration of the Gyrodyne GCA-2. The photos show the J with the registration [NX74102]. This proves that two prototypes were built. The Gyrodyne GCA-2 photos all show it to have been [NX7401]. and one source says the GCA-2 was previously the Bendix J-2. If these elements of information compute, then [NX74101] was the J-2 while [NX74102] was the J.
 
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