"V" tail on a Gyrobee¿

Falco

Newbie
Out of all the gyro's I've looked at I can't remember any with a V tail. I'm not saying I didn't see one but I can't remember. CRS maybe, who knows. Eventually, I plan on building the gyrobee with a V tail and was wondering if there's a reason why they're not more popular. Thanks

Falco
 

eddie

RAF, turbo subaru 230hp
They are not popular because of the instability problems associated with the "V" tail design.
 

Doug Riley

Platinum Member
The question "Why not a V-tail?" is better flipped on its head: "Why do it?" Always start with majority, proven methods and only go elsewhere if you can improve on them. IOW, don't re-invent the wheel.

The V-tail was a design fad decades ago, when it made its way into the Bonanza -- a fast, expensive plane for its time. The theory then was that each joint between the fuselage and a wing or tail surface produce a bit of drag -- and two joints made less drag than three. The gains even for a slick FW plane were marginal at best. In a gyro, which has the aerodynamics of a Port-A-Potty -- any possible gain is overwhelmed by the enormous drag of everything else -- especially the rotor itself.

The V-tail is more challenging to design and build, especially when attached to a slender tube such as the typical gyro tail tube. The "ruddervators" will produce a certain amount of adverse aileron effect when activated: e.g. rudder applied for a left yaw will also create right roll (so will an ordinary rudder, but not as much). This sets up a slip, requiring left stick. Who needs that complication? Some gyro designs do not tolerate slips very well at high speeds and throttle settings.
 

All_In

Gold Supporter
The V tail design was also described as a feature. Each Fin would try to become vertical using physics to keep it straight.
This causes the tail to waddle with each fin taking turns trying to take the vertical rudder position. As the fin that is closer to the horizontal is now closer to a HS it has more lift and push it back towards the vertical over correcting until the other fin push it back the other way.

Yikes, I hope that make sense it hard to explain in lay terms if you do not understand the physics.The benefit was suppose to be that it would average out and hold a course better.

I've flown a lot of them but Beach's hold a good course no matter what tail they have and I could not tell the difference between a Beach V tail and the normal tail..
I did notice the waddling tail but it's not a problem as long as you don't fly WAY over red-line.

There is a reason pilots called Bonanza "forked tail doctor killers".
The reason was the design and the fact that doctors did not seem to feel they needed to practice actual IFR flights.
They would get in actual and not be able to fly on instruments ending up in a dive.It dives like a rocket ship because it is so heavy and streamline.
Once they were over red-line the tail would waggle and break-off because of metal fatigue.

It took years of court battles before Beachcraft proved that the tail could only break off if the pilot exceeded red-line and the real problem was the doctors who could not fly IRF and maintain air-speed.

The V tail on a gyro would only cause more metal fatigue without much benefit and is why no manufacture has copied Beachcraft's design since.
 
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Brian Jackson

Platinum Member
I've been interested in the V-tail design as kind of a primer for understanding the forces in play, but not as an option for my gyro. I like the idea of having a rudder surface affecting upward airflow in vertical descents. I understand that on a traditional rudder a forward swept hinge line is more effective than a vertical hinge (and probably opposite for a rear-swept hinge.) It stands to reason that any significant sweep of the rudder hinge line will have an effect in pitch, and it seems like a V-tail would amplify this effect since most H-Stabs are at a fixed angle of incidence. Or am I way off in my understanding?
 
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