US Navy 1951 Observation / Liaison helicopter competition

I don't know about you, but all those obscure early rotorcraft fascinate me...
Here's a list of the known entries to a 1951 specification calling for an HO class helicopter (Observation) which would also be used for Liaison purposes:

• Convertawings C Quadrotor (XHOC-1)
• Flettner (designation unknown)
• Gyrodyne 22
• Gyrodyne 23
• Hiller HO-352
• Kaman K-8
• Kellett KH-14
• McDonnell 82 Convertiplane
• Medvedeff Monocopter
• Piasecki PH-49
• Piasecki PH-51/A Retractoplane

Apparently none of these types made it and the competition may have been cancelled... And yet, some strange element appears in the Spangenberg Index: the "XHOC-1" mention next to the Convertawings Quadrotor, which probably signifies that the type got a contract and therefore presumably won over the others. This is all the more surprising since the only Quadrotor prototype known (displayed at the Long Island Museum) is described as having once won a contract with the USAF, not the Navy.

Even more surprising, all the other contenders (apart from Medvedeff) were established companies in the field of rotary aircraft with solid proposals (the Convertiplane was procured by the USAF as the XH-35 / XL-25 / XV-1, but the Retractoplane, although carried over by Vertol, never generated any military interest).

Last but not least, the presence of Flettner, a famous German manufacturer of Luftwaffe fame, is kind of odd... Was there a US Flettner company at some point after war? Haven't found any trace of it...

Hi,

I think it was Piasecki PH-51/A retractoplane;

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930008694_1993008694.pdf

Stargazer2006 said:

Last but not least, the presence of Flettner, a famous German manufacturer of Luftwaffe fame, is kind of odd... Was there a US Flettner company at some point after war? Haven't found any trace of it...

Click to expand...

Yep. Anton Flettner consulted with the ONR in 1947-48. In 1949, he started his own R&D outfit, Flettner Aircraft Corporation, based in Queens, NY (working with Kaman and others).

BTW, a Deutsches Museum bio mentions a 40-passenger helicopter design but its not clear whether this "Großhubschrauber" was for the ONR, Flettner Aircraft Corporation, or... ?

"1947 wanderte Flettner in die USA aus. Was with- Mit seinem Büro Flettner Aircraft Corporation führte er eine Reihe von Aufträgen für die US Navy aus. Sein Lieblingsprojekt war ein Großhubschrauber für 40 Passagiere. Also for the U.S. Auch für die amerikanische Raumfahrt war Flettner tätig."

Hi,


I suggest that,may be those are the Gyrodyne GCA.22 and GCA.23;

May be or may be not. Hesham, I think we should stay away from speculation because, before you know it, somebody has taken such a speculation as being accurate.

Having said that, has any of you gentlemen done any detailed study on Gyrodyne designs - they seem to have made more designs than actual aircraft.

My dear Jos,


I made this speculation because I know many of Gyrodyne projects in "details",such as GCA.3,5,8,
9,21,24,32,33 & 35,and when I found some pictures to unknown projects,I can say: they are not all
previous list,finally when I do that,my anticipation is very close to realist.

I hear what you are saying but, having found the Gyrodyne designations elsewhere in this forum, it appears there are many missing such as GCA-13 to -20 and GCA-25 to -28.
The pictures you posted could be anyone of these.
Especially with so much data missing we got to be very careful with speculation.

hesham said:

Hi,


I suggest that,may be those are the Gyrodyne GCA.22 and GCA.23;


http://books.google.com.eg/books?id=1t4DAAAAMBAJ&pg=PA118&dq=popular+mechanics+vertiplane&hl=en&sa=X&ei=nxz_U8ezOOis0QWGr4HYDg&ved=0CCQQ6AEwAg#v=onepage&q=popular%20mechanics%20vertiplane&f=true

Click to expand...

23.png (image) looks 70 years ahead of its time if that was 1951. Concept looks very current like some of the high speed demonstrators.

That's right my dear Jos,


my idea was based on "Observation/Liaison" word,so I see this character in those two Models,but
no conclusions before knowledge,again you are right.

Hi,

for Nicolas J. Medvedeff,he had some convertiplane patents;

https://www.google.com/patents/US2819029?dq=nicholas+Medvedeff+airplane&hl=ar&sa=X&ved=0ahUKEwi9nd2845XLAhWGVRoKHUvXBpQQ6AEIVDAG

https://www.google.com/patents/US2738146?dq=nicholas+Medvedeff+airplane&hl=ar&sa=X&ved=0ahUKEwi9nd2845XLAhWGVRoKHUvXBpQQ6AEIXTAH

hesham said:

I suggest that,may be those are the Gyrodyne GCA.22 and GCA.23;

Click to expand...

And maybe that was GCA.22 & GCA.23.

McDonnell Model 82 here: https://www.secretprojects.co.uk/threads/mcdonnell-model-82-convertiplane.6955/

Stargazer2006 said:

Convertawings C Quadrotor (XHOC-1)

Click to expand...

Here it's,

https://www.secretprojects.co.uk/threads/convertawings-«-quadrotor-»-designs-models-a-to-f.7009/