[HH] Mystery signal from a helicopter

[Jerry Feldman]

This is true. In flight school we had OH-23s (Hillers) and OH-55s
(Hughes) The OH-55 was referred to as the Mattel Messerschmidt. It was a
3-bladed fully articulated system. The 2-bladed are semi-rigid usually.
Fully rigid Rotor systems are relatively new. Lockheed developed one in
the late 1960s but it failed military tests. But, at the time it was the
only helicopter capable of flying upside down.

On 02/04/2014 01:21 PM, Greg London wrote:
> Jerry,
>
> Thanks for the info!
>
> I think I glommed rigid and semi-rigid together. Memory is turning to mush.
>
> http://www.airspacemag.com/flight-today/how-things-work-ground-resonance-94660854/
>
> "The only rotors that can produce ground resonance are those with three or
> more blades."
>
> I googled a bit to try and find that video. I thought it was a MASH
> helicopter. maybe it was a brantly or a sikorsky 300. Couldn't find
> anything that looked like either one.
>
> Ah well. Won't be able to afford to fly anytime soon anyway.
> Greg
>
>
>> They used the Bell OH-13 (model 47) 2-bladed helicopter in M.A.S.H. The
>> "killer Hillers" were two-bladed (semirigid) with wooden blades. I used
>> to fly the Hiller OH-23 in flight school. Not only were they semirigid,
>> but they had paddles connected to the cyclic and no hydraulics. The Bell
>> had hydraulics.
>> Bell OH 23
>> *http://tinyurl.com/n5bmz6n
>>
>> *Hiller OS-23 Model 360
>> http://www.youtube.com/watch?v=TRDJ9oyjcMc
>>
>> On 02/03/2014 12:13 PM, Greg London wrote:
>>>> Most helicopters used by news organizations ...
>>>> Depending on whether they are semi-rigit or fully
>>>> articulated, each blade has its own independent angle of attack,.
>>> Most news helicopters are Bell Jet Rangers with 2 rotor blades.
>>> As far as I know, any helicopter with 2 rotor blades is rigid.
>>>
>>>> I have seen helicopters go into vibration on the
>>>> ground and destroy themselves.
>>> I've only seen video. It was an older Hiller "killer" model
>>> (a la "M.A.S.H.") with 3 rotor blades.
>>>
>>> I've got a chunk of time on a Robbie.
>>> Someday, I'll splurge and get an hour or two on something
>>> with a turbine. If I win the lottery, jetpack.
>>>
>>> As for the article, interesting way to pack data in to the audio.
>>> I wouldn't have been able to reverse engineer it the way the
>>> guy writing the article did.
>>>
>>> Greg
>>>
>>>
>>>
>>>
>> --
>> Jerry Feldman <gaf at blu.org>
>> Boston Linux and Unix
>> PGP key id:3BC1EB90
>> PGP Key fingerprint: 49E2 C52A FC5A A31F 8D66  C0AF 7CEA 30FC 3BC1 EB90
>>
>>
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>

-- 
Jerry Feldman <gaf at blu.org>
Boston Linux and Unix
PGP key id:3BC1EB90 
PGP Key fingerprint: 49E2 C52A FC5A A31F 8D66  C0AF 7CEA 30FC 3BC1 EB90


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