Tall Tail's

[Brian]

I don"t think I could"ve stirred up a bigger hornets nest if I"d gone into some V8 Supercars forum and posed the question, "So, which is better - Fords or Holdens?":PNo, its no hornets nest mate, just some good old fashioned jousting without absolutely any malice. The debate about tail feathers has arisen once in a while........ with the same predicatable debate, course, those who support the conventional tails are the ones who are correct.Flat spins are no problems with a normal tail, its just that you need to be correctly instructed in how to enter and maintain a proper flat spin. Some get into a backslide that will bring you undone.Murray, I waited all weekend to see you fly your gyro or at least let me have a go

[Brian]

My only comment is that a tall closely coupled tail sitting behind a wide 2 place cabin machine can become shielded from the relative airflow causing a wobble during, engine off or idle power settings.My 2 bob Cheers SamL..................Spot on Sam.

[asra]

Yes Sam you"re right. Any tail that is shielded behind a cabin,especially one with an abrupt end to it instead of being smoothly "faired" back into the prop will be a problem.On a different note but still in keeping with the different tail configurations is the thread on the US forum concerning a fatal crash in Mallorca.Especially the posts from Doug Riley. Ive done some serious sidslips in the old tandem but never felt comfortable. No real reason to do this for us hobby fliers so probably an area to stay well away from.

[mad max]

I"m impressed, Murray. Maybe It"s the vertical stabilizer that retards pulling out of a flat spin? Because the full turning tail seems to manage it ok, such as the Air Comand.

[asra]

I had a look at the video and its a pity it doesn"t show the whole display. The spinning tail slide I think got me disqualified and I didn"t win the trophy. I think one of the judges thought I was a bad influence. Not much changed there....Ive heard some theories about the vertical tail being blanketed by the HS in vertical descents etc.

[quoj]

Oy vey!Now I"m totally confused! Perhaps I should just flip a coin.Heads - tall tail.Tails - short.:P

[asra]

Go with whatever you like the look of and feel comfortable with. My personal preference is either a TT or something like the ELA"s or MT"s.Airfoil shaped HS somewhere in the prop stream, where it will get air over it at all airspeeds.Get the thrustline right.

[quoj]

Fair enough.I can live with that.Thanks, Murray.

[Greg Mitchell]

Just to be clear here.Murray said..."Tall tails are designed to be placed as near to the prop as practicable,3 to 5 inches. The whole idea is to cut the swirl effect before it starts,hence cutting out P effect. Put a TT to far away from the prop and have the height smaller than the prop diameter and the effect will diminish significantly."What Murray is saying here is true BUT only with regard to the negating of P factor effect.Murray would agree I"m sure that a large surface area,

[asra]

Yes and no Mitch.There"s no doubt the tails on the Butterfly range of gyro"s work well but ponder this,effect = free stream+induced. IE the air stream plus the high speed air off the prop dictates the force the HS can generate.A tall tail close in gets mainly prop blast(normally)plus negating p effect from being so close.A Tall tail 2 or 3 feet back gets the same amount of prop stream but is to far back to have any impact on p effect. More leverage yes but slower air, less force.Engine stopped however all things being equal,IE same size tails, then the further back the better.Someone once told me "A tall tail wont stop PIO with the engine stopped"

[GraemeMonro]

Yes and no Mitch.There"s no doubt the tails on the Butterfly range of gyro"s work well but ponder this,effect = free stream+induced. IE the air stream plus the high speed air off the prop dictates the force the HS can generate.A tall tail close in gets mainly prop blast(normally)plus negating p effect from being so close.A Tall tail 2 or 3 feet back gets the same amount of prop stream but is to far back to have any impact on p effect. More leverage yes but slower air, less force.Use the FORCE Mitch, use the FORCE.

[Greg Mitchell]

I"m pretty sure thats what I said Muzz.Tall Tail in close is effective with P Factor control but your also getting dirtier free air than a tail further back.Power on augmented stability with a Tall tail in close, less so with engine out.More rudder authority with the tail further back and cleaner free airstream than tucked up yar ass but still close enough to ream the benefits of power on augmented stability.I said quite clearly Muzz Goldens tail is not employed to counter P effect. It is employed in its primary function as a pitch dampener and when seen operating with all them other side by side, tandems and singles flying at Mentone it is neat to see the Golden punching thru air the others dont want to fly in.[b]Someone once told me "A tall tail wont stop PIO with the engine stopped"

[asra]

"They must have been thinking of a stab-less dunny door tail when they said that"No Mitch my point is that even the worst case high thrustline no horizontal stabiliser gyro you wont PIO or PPO engine stopped.

[quoj]

I"m sure I"m stating the bl00dy obvious here, but when the noise stops, there *is* no thrust line, "cause there *is* no thrust!(Except, of course, the violent puckering and un-puckering of the pilot"s sphincter as he considers the hilly, rocky tiger country all around him!)As for dunny doors in use as as tail feathers, has anyone seen this barely airworthy example of Cierva"s legacy:http://www.youtube.com/watch?v=pLiCibFeQPM

[Greg Mitchell]

No Mitch my point is that even the worst case high thrustline no horizontal stabiliser gyro you wont PIO or PPO engine stopped.Of course, I missed that one.