flying tail or fin and rudder?

[scottessex]

Just a question, I currently am taking lessons from Steve McGowan. My gyro flew last month for the first time, I have a Ron Menzie flying tail rudder. The guy that test flew it, Rick Abercrombie, has over 20 years flying his bensen.
He said the flying tail made it feel like it had no dierectional (left, right) stability. Could have been related to trim tab.?
My Question is, would a bensen style fin and rudder set up be more stable? here is a pic of what I have.
Even though it's as ugly as a mud fence, would it work better than what I currently have?? (I could easily make a better looking one),
pics of the current arrangement are on this forum under "Bensen" "new bensen on the block"

The curret arrangement uses the flying tail, and the rock guard, moved to the back of the keel.

The horiz stab on the one in the pic, is about 12" by 36"

Thanks for all input.

[scottessex]

Here is the current set up.
By the way , the boat tank will be gone soon, moving up to a seat tank.

[mceagle]

The rudder you have should be fine but it should be fitted with an anti-servo tab to give it a positive feel and to make it tend to return to "neutral" by itself.

[GyroRon]

IMHO it is best to get flying impressions from gyro pilots that are experienced in many different machines, not just one type. Not sure about Ricks experience but 20 years in one type will make Anything different feel weird.

[scottessex]

Good point Ron, I was just wondering if anyone else has changed out tails and noticed a marked difference.
And we have been adjusting the trim tab to try to get a neutral feel.
Thanks for the input.

[RHerron]

Without an anti-servo setup, you won't get a stable "feet-off-the-pedals" operation with the pivoting tail.
The only one of those I ever flew, I only flew once. I returned it to the original vertical/rudder configuration.
Your old Bensen-style tail looks like it is made from 1/2" board....very heavy.

[scottessex]

Yes it very heavy, I was thinking about making a new one from from some surplus 3/8" composite honeycomb aircraft floor panel.
But I didn't want to waste the time if it would not be an improvement.

[Screw]

Hey Scott,

Get a set of Plans from Ron Herron for his tail. We'd be twins.....You got to paint yours anyway. Mines orange and white with checkers, you could do any other color and white with checkers.

John-

[scottessex]

Well don't think I didn't plan on taking measurements next time I am down there!!! ;D

[Doug Riley]

That red tail IS ugly as sin, but aerodynamically it's an improvement in two ways: First, it has a horizontal stab placed in the prop slipstream, where it will be more effective at low airspeeds.

Second, the fin-rudder combo (complete with servo surface and counterweight) has positive stability AND actually more power per square foot than a one-piece job. This second point doesn't necessarily seem right, but it's true: the combo amounts to a flapped airfoil when it's deflected. Flaps add power to airfoils.

An all-flying rudder is less fussy to build and is a favorite with manufacturers for this reason. If a HS is added to one, however, the HS has to pivot with it, which is a pain. You have to give the HS sweepback to keep it out of the prop when the rudder is deflected.

The axle of the all-flying tail has to be placed at the aerodynamic center of the airfoil to avoid either instability or poor stabilizing properties. However, when you do this, you deprive the pilot of all pedal "feel" unless you also add an anti-servo mechanism. With a proper anti-servo tab such as the one on Ernie Boyette's tall tail, the one-piece rudder will feel and act normal.

BTW, a Bensen tail doesn't HAVE to have sharp corners. Igor showed straight cuts on the plans so you could chop one out with a circular saw. It's OK to use a jigsaw to create a more rounded shape if you like, as long as the distribution and sizes of the areas ahead of and behind the hinges stay the same.