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  #11  
Old 09-02-2020, 07:24 PM
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Quote:
Originally Posted by Ez2cDave
Look up the term "Bentert Actuator".

Dave F.

Like a cross between a motor and a solenoid. How much rotation did it get, ~90 deg?
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  #12  
Old 09-02-2020, 10:48 PM
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Quote:
Originally Posted by tbzep
Like a cross between a motor and a solenoid. How much rotation did it get, ~90 deg?


I saw one, in person, on Guppy Youngren's RC B/G at NARAM-17, in Orlando, FL, in 1975.

I believe it was a "pulse-control" RC system. ( I was 14, at the time )

When there was no transmitter output, the Bentert Actuator would "flutter" the Rudder back & forth, continuously, at a high rate. Whenever there was output, the Rudder would only "flutter" from the Center to one extreme or the other, depending if Left or Right turn was desired.

As I recall, the Glider was "Rudder-only".

To the best of my recollection, Rudder travel was about 45 degrees, in each direction, for a total of approximately 90 degrees, total travel.

Dave F.
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Last edited by Ez2cDave : 09-02-2020 at 11:19 PM.
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  #13  
Old 09-03-2020, 01:19 AM
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As Bunny said, pulse proportional. The amount the rudder favored being on one side of neutral vs. the other as it flapped back and forth was proportional to the rudder stick position. See also Adams actuator, Ace Pulse Commander transmitter. Bentert actuators were smaller/lighter/weaker than even an Adams Baby.

Not on/off or right/neutral/left only, but proportional control.
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  #14  
Old 09-03-2020, 08:16 AM
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Quote:
Originally Posted by BEC
As Bunny said, pulse proportional. The amount the rudder favored being on one side of neutral vs. the other as it flapped back and forth was proportional to the rudder stick position. See also Adams actuator, Ace Pulse Commander transmitter. Bentert actuators were smaller/lighter/weaker than even an Adams Baby.

Not on/off or right/neutral/left only, but proportional control.


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https://www.youtube.com/watch?v=HLVk97zI2lg


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  #15  
Old 09-03-2020, 11:26 AM
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Quote:
Originally Posted by tbzep
Tail wags like a happy puppy.
https://www.youtube.com/watch?v=HLVk97zI2lg


I don't know whether to be amused or appalled that someone has created a little adapter that will drive an Adams (or Bentert) actuator from a modern receiver.

I remember putting actuators on removable plates like that for exactly the reason stated. An Ace Pulse Commander system was the least expensive single channel proportional system one could buy in those days (very early 1970s) but to a high school student like me they were still quite expensive.
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  #16  
Old 09-03-2020, 01:17 PM
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Thankfully I never got into RC with any of that early CLUNKY pulse single channel guff.
I started in 1977 with a Kraft 6 channel proportional setup.
Quickly switched to Futaba a year later. Much more value for your $$.
I can't imagine trying to fly with less than 3 proportional channels.
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  #17  
Old 09-03-2020, 01:38 PM
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Quote:
Originally Posted by ghrocketman
Thankfully I never got into RC with any of that early CLUNKY pulse single channel guff.
I started in 1977 with a Kraft 6 channel proportional setup.
Quickly switched to Futaba a year later. Much more value for your $$.
I can't imagine trying to fly with less than 3 proportional channels.

Did you do a Kraft transmitter kit or was it already built?

My first Tx was a Futaba 7NFK because I caught it on sale for nearly the same price as the 4 and 5 channel radios at the time. I didn't think I'd ever need 7 channels, but all those switches and knobs looked cool. I have a 7UAF now, but I haven't flown anything in several years. Now that electrics have matured, I could probably have some fun in my pasture by converting my fun-fly planes and have the power to manuver without having to mess with cleaning the castor oil off. I had room to fly my Zagi with the old heavy ni-cad packs and 400 can motor. With today's tech, it should nearly reach orbit.
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  #18  
Old 09-03-2020, 07:23 PM
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My first RC was a 10-channel reed system. Bang-bang, you manually pulsed the sticks to flop the control surface in either direction. Circa 1965. Weighed a ton. 'Pulse' the sticks to get 'proportional' control. 'Reed' refers to the tuned strips that vibrated in response to a particular audio tone sent by the transmitter. 2 channels per surface.
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  #19  
Old 09-03-2020, 07:29 PM
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Quote:
Originally Posted by dholvrsn
I have since found that nearly all that stuff is available for download in the members section of NAR website. I've been snagging it. I didn't realize that the MIT club designed so many RCRGs in the '70s.


Can you mention the spot in the Memberís area where the MIT documents are? I searched earlier today and came across a lot of stuff, but I was not able to locate those documents.

Thanks in advance!

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  #20  
Old 09-04-2020, 08:17 AM
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Quote:
Originally Posted by astronwolf
LOL.. I'll send you a scan for free if we can find out who the copy right holder is. Please no one buy this it is such a ripoff. NAR sells old plans like this via NARTS - equally a ripoff.



QUOTE : ( from the Table of Contents page, contained in all volumes of MITRS that I have )

The Journal of the MIT Rocket Society is an annual compendium of the
Research and Development efforts of the members of the Massachusetts
Institute of Technology Rocket Society, distributed free of charge
to selected individuals and sections of the National Association of
Rocketry. Comments by the readers are invited. Submit them to
MIT Rocket Society, MIT Branch PO Box 110, Cambridge, MA 02l39.
Permission is granted to reproduce the contents in whole or in part
for nonprofit purposes, provided proper credit is given both to the
author and to this Journal.


Dave F.
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