Torque roll.

[Aussie_Paul]

One thing that I am finding with hybrid in rough weather is that when a gust etc unloads the rotors I get a marked roll to the left in sympathy with the prop torque.

This can be a little disconcerting for the new student, as the rest of the operational areas are great. Admittedly I have been conducting Trial Instructional Flights in gusty thermally rough weather.

The south easterlies that we have at this time of the year, that I hope will blow me up to the center of Oz for our National Easter get together, are a very rough winds down here due to the wind coming over the city and a couple of mountains. The wind from any other direction can be strong and rough, but it does not change direction and strength from one second to the next.

The torque roll is something that I would like the experts to comment on for me please.

Aussie Paul.

[StanFoster]

Paul: I am no expert...so I am just going to add another question to your excellent post.

I am not scratching at straws here looking for any advantage that HTL may have over CLT. It is well documented CLT is the way to go..but with that said....my question.,,

I have always wondered that with HTL...if the CG that is below the thrustline does not in itself have some anti torque effect. The way I see it ...the CG has a certain moment arm of torque being applied at 6 o/clock from the thrustline. Doesnt this have some torque effect to minimize some of the torque rollover from the engine torque? It would seem that the CG right on the thrustline would spin around the thrustline easier making CLT more succecptible to rollover effect.

We all know that HTL is not as stable pitch wise...but to rephrase my question...is HTL more stable roll wise ?

I also think that if this is true...it isnt that much to deal with...and the tail that the SparrowHawk has would easily compensate for this.

[Doug Riley]

For a minute, I think I saw "pork roll" instead of torque roll. Must be supper time.

Paul, what kind of tail do you have? Bensen/RAF style or a full-span "tall tail?" Without a tall tail, the rotor compensates for torque-induced rolling tendencies. Of course, in low G, the rotor's thrust is diminished and the torque roll tendency comes back. It's the same kind of problem you encounter when using rotor force (instead of a HS) to counter a high thrustline -- it's not too bad until you hit low G and the rotor thrust isn't there anymore. Then it's PPO time.

Many PPO accident reports mention the gyro rolling over as well as pitching over. The torque-over effect was caught on film in the case of the Wallis/"Pee Wee" Judge accident at Farnborough, England.

A big enough HS centered in the propwash helps to eliminate torque roll, even if you don't have a tall tail. If the HS is mounted well below the center of the prop, however, it won't help in this regard.

[EI-GYRO]

Hi Paul,

Perhaps with your improved pitch stability you could be
less inclined to back off the airspeed in turbulence.
Thus although your pitch might be satisfactory you might
actually be getting lighter on the rotor than you might
have previously done, thus getting nearer the torque
roll region.

e.g. better brakes on your car, so you drive faster, then find
the corners catch you out more, ????.

This suggestion is possibly worth no more than
you paid for it.

Cheers.

Fergus Kavanagh.

P.S Clocks change tonight, gyro season officially begins.

Fitted an altimeter today. How's that for optomism !

[EI-GYRO]

or even optimism

[Aussie_Paul]

Could be Fergus, but we have to fix it, and so that is why I posted.

Trying to get a better understanding of how it works.

Aussie Paul.

[quadrirotor]

Ok with Doug, and a tall tail gives a little more thrust in straightening the vortex behind the prop...
May be an other answer (to compensate gyroscopique forces too!...):

[quadrirotor]

May be an other one:

[quadrirotor]

A bit of power on the rotor could prevent the Rrpm decay, and at the same time could compensates, to one extent, the roll by inducing a yaw...(see the article on the Bensen powergyro).
Paul, in the situation you describe, you'd better have all the draggy parts above the C.G. and lessen the Cx of all the parts beneath the C.G. to reduce the likelyhood of a PPO. (HTL) or even a bunt over without power if the slowing prop. antithrust is beneath the C.G. (LTL)(the weight of the non-working rotor at the end of a tall mast could level the C.G. very high!...).

You have a right turning prop! so if you have a nose up attitude: the left roll (torque) is aggravated by the fact that the descending blade of your prop has a higher AOA than the ascending blade...so a left yaw...

What is said above could not apply to your case!...The dynamics of the gyro flight is complicated enough that you have to deduct yourself the figures and results for your very case for each phase of the flight, what's so ever could append...What is said, here, is only to give you some elements of reflexion!...