Bendix Helicopters Model K "Whirlaway"

[Stargazer]

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...).

 

[walter]

Hi Stéphane
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!

 

[Stargazer]

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...

 

[walter]

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

 

[Stargazer]

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...

 

[Stargazer]

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.

 

[Stargazer]

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").

 

[walter]

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?

 

[Stargazer]

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

 

[Mark Nankivil]

Greetings All -

Here's one to add to the confusion, or maybe add some clarity! From the Gerald Balzer Collection.

Enjoy the Day! Mark

 

[cluttonfred]

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]

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

Also courtesy of the Gerald Balzer Collection.

Enjoy the Day! Mark

 

[walter]

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 .

 

[Stargazer]

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]

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

Enjoy the Day! Mark

 

[hesham]

Hi,

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

 

[Mark Nankivil]

Good Day All -

A nice look at the airframe and drivetrain of the Model K. From the December 1946 issue of American Helicopter.

Enjoy the Day! Mark

 

[Mark Nankivil]

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

 

[Stargazer]

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.

 

[Petrusja]

I found a photo of the Bendix K NX41817 at NACA Langley
https://www.airhistory.net/photo/655368/NX41817
and did some further digging.

It was the first Bendix helicopter to fly, already on 30 June 1945 according to Vertical Flight Society. And attached is the photo of the enclosed version with an old dating saying... 27 November 1945!

If this is correct, it is rather odd that American Helicopter published a photo of the uncovered version more than a year later. I'm still assuming it first flew uncovered.

But I do think it's likely that the open cockpit version is the third version and not the second. An easy explanation would be that the fully enclosed version didn't work. It looks like a lemon doesn't it?

The open cockpit version was certainly around in January 1947, see second attachment. There's also a photo in a North Carolina archive dated 1948-49, but that may be unreliable:
https://digital.ncdcr.gov/Documents/Detail/one-man-helicopter/359727

Unfortunately the NACA Langley photo is not dated.

I agree there probably was just one K.

Peter

 

[Stargazer]

It was the first Bendix helicopter to fly, already on 30 June 1945 according to Vertical Flight Society. And attached is the photo of the enclosed version with an old dating saying... 27 November 1945!

If this is correct, it is rather odd that American Helicopter published a photo of the uncovered version more than a year later. I'm still assuming it first flew uncovered.

Your comment is confusing, because the dates you are giving are in sequential chronological order. Or did you mean 30 June 1946?

I agree there probably was just one K.

I agree, too. According to my own research, only one Model K [NX41817, c/n unknown]. The open frame version flew first in 1945, then the totally enclosed version in 1946, and finally the partially open cockpit, probably in 1947.
Oddly enough, the Model J (also called Whirlaway) came after the Model K. There were two protoypes: the J [NX74102, c/n 2] and the J-2 [NX74101, c/n 1], the latter becoming the Gyrodyne GCA-2.

 

[Petrusja]

Your comment is confusing, because the dates you are giving are in sequential chronological order.

Hi Stargazer, I just meant that the magazine published a photo of the older version, without commenting on that. But it's of course possible.

The open frame version flew first in 1945, then the totally enclosed version in 1946, and finally the partially open cockpit, probably in 1947.

It seems you knew a bit more than you shared so far.

Yes, more or less, but the photo of the fully enclosed version seems to be dated 27 November 1945. And the open cockpit version was demonstrated at Fort Monroe on 6 January 1947, so it most probably first flew in 1946.

A NASA document says that NACA bought 'the Model K' 'when Bendix dissolved in 1949'.

Oddly enough, the Model J (also called Whirlaway) came after the Model K

Yes, that is odd. Apparently they optimistically designed the J first and then built a smaller test vehicle. Only when the commuter helicopter for the masses didn't materialize, they tried to market the Model K I think.

NX41817, c/n unknown

Ed Coates gives c/n 1 for what that's worth:
http://www.edcoatescollection.com/ac3/Classics/Bendix Model K.html

I would to upload your first photo of it, with the water tower, at AirHistory. Would you like me to credit you or someone else?

Peter

 

[Stargazer]

I would to upload your first photo of it, with the water tower, at AirHistory. Would you like me to credit you or someone else?

It's a photo I saved years ago from an online auction, it's not my property, nor should I take any credit for it!

 

[Petrusja]

It's a photo I saved years ago from an online auction

I don't care where you got it, it's just a matter of courtesy, not of copyright.
If you know it's a Bendix photo, I'll credit it to Bendix.
If not, it will go into my 'collection'. But thanks.