Rudder - Horizontal - Tails

[lanichol]

It appears the delta horizontal, vertical windlets, and rudders on many of the various gyro manufactures look nearly exactly the same.

Is there a common manufacture for tails? Can a person purchase the individual tail outside the kits?

Thanks

 

[WaspAir]

I always assumed it was one part don't-reinvent-something-that-works and one part style/fashion that contributed to the look-alike designs you see.

 

[Abid]

That RAF tail I think maybe its called Boyer tail or something like that. I think you can buy that one standalone

 

[okikuma]

No one common manufacturer. All just following the "leader."

To paraphrase the late Chuck Beatty, all the European style of gyroplanes are just glorified designs from the original Bensen Gyrocopter with an added horizontal stabilizer.

Why the three vertical stabilizers? An attempt to counter the "weather vane action" of the vertical surface area of the forward fuselage that is in front of the lift vector of the rotor.



I will say that the combined surface area of the central vertical stabilizer and the two additional outer vertical stabilizers on the horizontal stabilizer is very close to being equal to one tall cruciform vertical and horizontal stabilizer that Ernie Boyette designed for the Dominator.

Wayne

 

[okikuma]

I am mystified why the tall cruciform tail was replaced with the following on the Sparrowhawk Conversion RAF 2000.

Wayne

 

[bugflyer]

I am mystified why the tall cruciform tail was replaced with the following on the Sparrowhawk Conversion RAF 2000.

Wayne

Weight? Moment arm?
smiles,
Charles

 

[Vance]

I am mystified why the tall cruciform tail was replaced with the following on the Sparrowhawk Conversion RAF 2000.

Wayne

Why? Are you asking a question Wayne? What is the question?

 

[Brian Jackson]

I just noticed that the yellow Sparrowhawk pictured above appears to have all 4 wheels on the ground at once. Wouldn't this prevent rockback on takeoff which I'm told affects TO distance? And how much main gear travel is there if the tailwheel and nosewheel are already touching the ground? Just curious why this arrangement was designed.

 

[Vance]

I just noticed that the yellow Sparrowhawk pictured above appears to have all 4 wheels on the ground at once. Wouldn't this prevent rockback on takeoff which I'm told affects TO distance? And how much main gear travel is there if the tailwheel and nosewheel are already touching the ground? Just curious why this arrangement was designed.

Too much rock back on takeoff allows a gyroplane to lift off prematurely.

The pilot controls rock back.

On the yellow modified RAF the tail wheel appears to me to have suspension with a swing arm and the tire can move up behind the keel; I don't know how far.

Some gyroplane pilots when landing favor touching the tail wheel down before the mains to straighten the gyroplane out before the mains touch down particularly in a cross wind.

With the RAF or any side by side it can be difficult to tell what is exactly pointed in the direction of travel and touching down the tail wheel first may help with that.

 

[lanichol]

Ya, The Yellow Sparrowhawk was the one I purchased from Kenny Sandyeggo N9KJ. It was the first RAF to RAF Sparrowhawk conversion done by the factory in Buckeye. It did not have the 6 inch clearance on the tail keel wheel. Greg Bradley changed it to a 4 in tool chest wheel (looks like a giant skate wheel), so it could rockback father on landing.

It did not have a trim tab on the tail, and the tail wagged. Kenny on a takeoff turned right nearly 45 degrees the day I purchased the gyro at Gillespie Ca. There was no wind that day. It took me a couple years to figure out the importance of the little antiservo. It was terrible susceptible to cross winds. It had a tenancy to pitch up or pitch down with power settings. Several people tipped the engine down 7 degree on RAFSparrow and Sparrowhawks. 5 blade prop helped for some strange reason the problem with power & trim. Trim setting on takeoff was heavy. Using a Gyrotech head (blades) (fits both RAF/Sportcopter head) there is less leverage height and a lighter hubbar. The trim becomes light, simple and easy. And gyrotech blades tend to fly 10 mph faster. Not a bunch of tension on heavy springs or air system.

Larry Boyers RAF Sparrow was reversed to a RAF tail and his horizontal. Flys great. He has sold over 70 horizontals.
Matt's "Sparrowhawk" has a Sportcopter tail and a Stabilator for trim. (Finally a solution for the Sparrowhawks!)
Brent's Drop keel, 6 inch lower engine, horizontal, stabilator, grass tires, 2.5 4 blade sold in one day. The RAF is now cross country.
Larry Ellerman sells a horizontal with vertical wingletts. Its fast. Similar to the Don Parham.

It would be nice if someone would European one piece delta horizontal and rudder to retorfit that Sparrowhawks/RAFs.
It is a valid option in my opinion. Is it needed? The RAF with the stabilator and the tail moved back maybe all that is needed.
The RAFSA sure fly alot of hours. And if you build 2.5 engine right, way more HP than a turbo rotax at 4 gal hour.
So why pay the extra 50K? Certification right? Close to 400 RAFs in the US.

All we need is a European tail. So who sells only the rudder/horizontal at a somewhat reasonable price.

 

[Doug Riley]

People from the Magni school of thought disagree, but I believe that a horizontal stab on a typical slow pusher gyro is incompletely effective if it is not at least partially immersed in the propwash. The airflow over a H-stab that's located on the keel tube is too slow and turbulent to provide ideal pitch stability. This is particularly true of gyros with high thrustlines.

A low H-stab on a HTL gyro will, in low-G conditions, initially allow the nose to drop. This is the beginning of a PPO. In Magni and similar configurations, the stab will eventually "bite" and arrest the PPO. But IMHO it's better for the nose to go the right way (toward the relative wind) in the first place.

But styling takes precedence. A tall tail looks ungainly to some, no matter how well it works. The Magni triple-tail looks racy.

 

[okikuma]

It did not have a trim tab on the tail, and the tail wagged. Kenny on a takeoff turned right nearly 45 degrees the day I purchased the gyro at Gillespie Ca. There was no wind that day. It took me a couple years to figure out the importance of the little antiservo tab...

Ever since the development of the "all flying" control surfaces, they require an anti-servo tab to prevent "control hunting" or "control float."

... It had a tenancy to pitch up or pitch down with power settings.

With the horizontal stabilizer within the prop wash, the increased airflow would conceivably cause the nose to pitch up, especially if the stabilizer has some negative angle of incidence to the airflow causing to lift the nose. The decrease in airflow would reduce the nose pitch up along with the added drag of the slower turning propeller (propeller disk) causing the nose to pitch down.

Larry Boyers RAF Sparrow was reversed to a RAF tail and his horizontal. Flys great. He has sold over 70 horizontals.

How many of the 70+ Boyer horizontal stabilizers sold were used on a Sparrowhawk original tall cruciform tail has been removed?

Matt's "Sparrowhawk" has a Sportcopter tail and a Stabilator for trim. (Finally a solution for the Sparrowhawks!)

Since I have never flown or flown in a Sparrowhawk, I'm unaware of the idiosyncrasies you have mentioned. I'm just surprised that some Sparrowhawk owners are changing their empennages to be more like Sportcpter M2 format.



Wayne

 

[Rowdyflyer1903!]

It appears the delta horizontal, vertical windlets, and rudders on many of the various gyro manufactures look nearly exactly the same.

Is there a common manufacture for tails? Can a person purchase the individual tail outside the kits?

Thanks

In the back of my dusty mind, there was an ancient formula that the horizontal area was a percentage of the total disk area. This must have been from the pre Bensen era as horizontal stabilizers were not used in those designs, excluding of course the rock guard.

 

[Abid]

Anything that has or can have a negative pitching moment has to have some way of balancing it by dampening so Pilot retains time and control to correct a rotational tendency in pitch.
Even if rotor disc creates zero pitching moment in all expected flight regimens, even the slightest high thrust line will create a negative pitching moment. In a two seat gyroplane just going from a single occupant to a two occupant setup changes the vertical location of CG noticeably. CG going down if there are two people instead of one usually. AR-1 is 5 inches high thrust line with one person and roughly 3.75 inches high thrust line with two. So you have to take the worst case and create a dampening and balancing mechanism that is acceptable. In worst case it should provide a trained average pilot time to correct the situation. However, worst case cannot be considered sustained low to zero G or negative G. In that case no matter what thrust line you have the rotor looses enough rotor RPM to start destroying the gyroplane itself and cannot recover. It is completely out of its flight envelope.transient low or even zero G that will undoubtedly be in weather conditions can be handled without too much problem.

In low thrust line designs like the Dominator part of the dampening or correction is coming from the thrust or engine power itself and a negative pitching moment is not constantly present when power is on. Instead opposite is true which does have its own set of compromises. In other high thrust line machines the correction is mainly aerodynamic balancing surfaces and in cruise you have a balance achieved like a see-saw hooked to balanced springs just as in an airplane where wings usually have a negative pitching moment always and the tail is always in play balancing that out.

 

[GyroChuck]

In the back of my dusty mind, there was an ancient formula that the horizontal area was a percentage of the total disk area. This must have been from the pre Bensen era as horizontal stabilizers were not used in those designs, excluding of course the rock guard.

Is this what you mean. I found this Excel file if the link works.

HS lift calc.xls

Sheet1 Mass density of air (see table below),Velocity of air across HS (mph),Coefficient of Lift (see table below),Surface Area of HS (sq/ft),HS Distance from aircraft CG (ft),Thrust (lbs),Prop Thrust Offset (inches) 0.00238,45,0.4,4,5,400,6 Lift of HS,2.07,lbs/sq. ft. Total Lift Force,8.29,lbs ...

docs.google.com

 

[Resasi]

It appears the delta horizontal, vertical windlets, and rudders on many of the various gyro manufactures look nearly exactly the same.

Is there a common manufacture for tails? Can a person purchase the individual tail outside the kits?

Bit late in replying Ian, but yes, Denis at Gyro Technic does sell a tall tail as a separate unit, that looks similar to that on the Yellow Sparrow Hawk but I imagine will be smaller in area.

At present these are on his GT-VX1 and VX2 single seat gyros. On my VX2 I find very little adverse yaw or pitch with throttle variations and although provision had been made for horizontal tail trim adjustment we found that it simply wasn't needed.

 

[Gyro Technic]

Bit late in replying Ian, but yes, Denis at Gyro Technic does sell a tall tail as a separate unit, that looks similar to that on the Yellow Sparrow Hawk but I imagine will be smaller in area.

At present these are on his GT-VX1 and VX2 single seat gyros. On my VX2 I find very little adverse yaw or pitch with throttle variations and although provision had been made for horizontal tail trim adjustment we found that it simply wasn't needed.

I've had several inquiries about our tail on a Sparrow Hawk, although I don't feel it would be quite large enough.
(I will be producing a larger version in the future, but no firm date on that as of now)

Tall Tail - Gyro Technic - Tall tail assembly for gyroplane

56.5" tall tail. Stationary leading edge with independent rudder section. The 48" wide horizontal stabilizers are (ground) pitch adjustable.

gyrotechnic.com

Especially as of late, we have been selling quite a few of these.
Most are being used as an upgrade to the full-flying tails on Dominator-type machines, along with one-off creations with very positive reports.

All internal ribs are machined from solid 1/2" 6061-t6 .

More internal details can be found here:

https://gyrotechnic.com/wp-content/uploads/2023/12/Leading-Edge_Tail.pdf

https://gyrotechnic.com/wp-content/uploads/2023/12/Horz-Stab_Sub-Assy.pdf

https://gyrotechnic.com/wp-content/uploads/2023/12/Rudder_Sub-Assy.pdf

Assembly video here:

Denis