T-bar cyclic

August 10, 2010 by Tim McAdams

 

In 1978 Frank Robinson was granted a patent for a T-bar cyclic flight control system in a helicopter. His concept was a departure from the conventional helicopter flight control design where the cyclic control came up between the pilot’s legs. During the last 30 years the T-bar cyclic in Robinson helicopters has generated a lot of comments.

Conventional cyclic control in S300R66 with T-bar cyclic control
 

Robinson’s objective when designing the R22 helicopter was low cost and mechanical simplicity and the T-bar cyclic fits this design goal by reducing the complexity, weight, and cost of the conventional flight-control system. Other advantages include ease of getting in and out of the helicopter and a comfortable flying position as the pilot’s arm can rest on top of his leg. Moreover, not having the control between the pilot’s legs allows for a narrower cabin, which lends to a more aerodynamic fuselage design. Robinson used this arrangement on the larger R44 and the soon to be certified turbine- powered R66.

I have flown many different helicopters with the conventional cyclic design and do not see any difference in the T-bar’s ability to control the helicopter. Also, I agree with the claims of increased comfort while flying and find entering and leaving the helicopter much easier as well. I view it as simply different and believe with just a small amount flight time with the system most pilots will discover that it works quite well.

Still, like all systems, there are unique issues that need to be addressed. One is that the horizontal control bar pivots, allowing the pilot to lower the hand grip to his leg. I have seen pilots struggle with the control’s ability to move up and down while in flight. Once they get comfortable resting their hand on their leg, that goes away. Also, when giving dual instruction–especially to primary students–the instructor needs to pay close attention to the controls and keep his hand close to the cyclic grip, which can be fairly high up when the student is flying. Another point, even with the dual controls removed, is the access the front-seat passenger has to the flight controls. I have had pilots tell me that when giving rides they have had passengers grab or bump the center stick.

The T-bar cyclic works well, however, as with any aviation system, a complete understanding of limitations coupled with good student/passenger briefings is important.

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14 Responses to “T-bar cyclic”

  1. Ray Runion-- From Frederick!!!!!!! Says:

    Hi tim from Ray Runion give me a call 540-204 5539

  2. Ehud Gavron Says:

    It is tough to find… but it is:
    http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4,114,843.PN.&OS=PN/4,114,843&RS=PN/4,114,843

    Ehud
    P.S. I didn’t call Ray… you might want to ;)

  3. Bob R. Says:

    I never have, and never will instruct in a helicopter with a t-bar. I consider it unsafe to instruct in. I am ATP/CFI/CFII in helicopters.

  4. pdxpilot Says:

    I only have a few hours and fly rotorcraft recreationally – I started in a R22 and finished in the Schweizer. I am much more of a fan of each pilot having their own cyclic. Plus you can move the T-bar and it not impact the rotor system which seem weird.

  5. Michael Says:

    Thank you for this well written overview. As a new helicopter pilot who did all their training in the R22, I find your assessment spot on. While not having the experience of other configurations, the T- Bar is working very well for me. I would caution that if you plan on stowing say a chart under your right leg while in flight ( isn’t cockpit management fun in the R22) that you carefully raise your arm and cyclic first before lifting your leg. With your arm in it’s usual comfortable flying position, if you quickly lift your leg while griping the cyclic, you will upset the aircrafts attitude abruptly. That has been my experience and I am very careful about this now.

  6. Ehud Gavron Says:

    I am a low-time pilot (130+). I have some 206 time, but most of my time has been in the R22 and R44. The T-bar cyclic, while much less “sexy” than the standard cyclic is workable. If you rest your hand on your knee (and lift it up carefully as the previous poster said :) you have the same control as in anything else.

    I recall when I first started flying that it was strange I could move the control up and down and nothing happened. This is different from the standard cyclic controls that CANNOT be moved up and down. Eventually this too became second nature.

    Judging from the reactions … the T-bar cyclic DEFINITELY polarizes people. (I was going to say “maybe polarizes” but didn’t want to be indefinite.)

    Happy weekend.

    Ehud Gavron
    Tucson AZ

  7. Dale Long Says:

    Different is neither good nor bad. My first little while using the T-bar was weird for me too. It got better once I figured how to keep my forearm on my leg and not lift it up. Instructors work the T-bar during instruction with their hand way up high and be very smooth.

  8. Ehud Gavron Says:

    …to add one little comment to the design of the T-bar cyclic control, a problem I HAVE noticed is that when the instructor’s hand is way up, and he/she depresses the PTT button, they often hold the cyclic in a rigid position preventing it from moving forward…

    E

  9. Robert Howland Says:

    I am an old guy with helicopter and fixed wing experience over a long time and I have a visceral rejection of a control system that will move in any direction without effect. A helicopter is by defintion a machine which beats the air into submission and as such needs real controls. Besides, I see no location on the T-bar for gun controls or hook drop or servo adjustment. There is certainly a market for the Yugo factor in aviation………I just prefer more quality in my equipment.

  10. helios Says:

    First, the Robinson was not intended to be a trainer. It was intended to be a affordable helicopter for the experienced helicopter pilot. Hense all the problems you read about in the NTSB reports concerning Robinson. Second, who doesnt rest their arm on their leg when flying a conventional control set up????? I have flown both and Robert is correct, I would rather have positive control over something that theoretically cant fly. (Military and Civilian pilot with 5500+ hours in helicopters)

  11. Jon With No H Says:

    As a CFII, I find the high grip on the instructor side isn’t quite the issue people make it out to be. For following the controls, you can always have the center column in easy reach down low and the aircraft is flyable with that, without needing to chase the grip around in space. With a foot switch for PTT as well, you can recover from any necessity quickly and take your time about getting your hand back up on that little grip.

  12. George Says:

    At the Robinson Safety Course this Spring they also said that the one of the original intentions was to “reduce lateral sensitivity” of the cyclic with this design. The R22 didn’t have hydraulics so Frank determined that he could achieve greater lateral throw of the cyclic with the t-bar than with a conventional design between the pilot’s leg. Another sometimes unknown fact is that there is a wind-up piano spring in the t-bar that helps balance the control when the co-pilot side is removed.

  13. Geo. of Florida Says:

    When I first received instruction in the R22 I found the T-bar to be rather odd and a matter of getting used to. It breaks away from tradition and I have to agree with those who feel that it goes against the “grain” of a standardized type of cyclic control (IMHO). Many pilots wonder why Frank Robinson never offered a conventional cyclic stick as an option, as I’m sure many pilots would have gladly paid the extra cost for such a conventional cyclic control stick. If the R22/R44 used conventinal controls , there wouldn’t be any need for a sense of transition to the conventional cyclic. The T-bar does allow for easy entry/exit , but I have heard far too many pilots curse that T-bar cyclic design. Yes, it’s all a matter of personal preference and I would hope that a conventional system may soon be in the works at the Robinson factory. Just my 2 cents.

  14. rangerb3 Says:

    I agree with helios…”Who doesn’t fly helo’s without resting their arm on their leg?” I started my helo training/flying back in the 80′s with a 10,000+ hour helo CFI all the way through to my commercial and he always stressed being smooth on the controls by using the arm on the leg technique. If I brought my arm up off my leg, it had to be for a very good reason!

    My transition training on the R22 was pretty quick and to the point, “take this bird over to this town and drop it off…oh and hurry it up!” Without too much thought or fuss, I jumped in, spooled it up and took off! Of course those were the early days and I was very young and “bullet proof!”…but, the “T” bar just didn’t have to much of an effect on what had been ingrained early in my training…it just naturally felt good and right to use the arm on the leg technique in the R22 from the begenning!

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