Aeleron effectiveness (especially British)

JG1Schorner · 26 January 2007, 06:59 AM

I was hoping to get a bit of information about aeleron effectiveness in various WWI aircraft. In particular, how effective was the British 4 aeleron configuration compared to other aircraft of the day? I have often heard it said that the Fokker D.VII was the first aircraft with really effective aelerons. I have also heard that aircraft like the SPAD XIII and Fokker DRI had relatively poor aeleron authority. How did the Pup, Triplane, Camel or SE5a compare? How did these British aircraft compare to other German aircraft like the Albatros series or Pfalz aircraft? And ... why?

Any input on the aeleron effectiveness of any other aircraft is appreciated too.

Thanks.

YavorD · 27 January 2007, 02:06 AM

Hi JG1Shorner,

A link to an old British report from February 1918 is attached below.

http://naca.central.cranfield.ac.uk/...arc/rm/413.pdf

The same source contains several more documents.

Also, Greybeard opened a thread about aileron deflection angles couple of months ago. This thread contains references to other documents, as well as some data.

Regards,
Yavor

JG1Schorner · 29 January 2007, 10:34 AM

Thanks Yavor

Scott McGowin · 1 February 2007, 09:34 AM

I think the aileron effectiveness of the early fighter aircraft has been greatly underestimated.
Why just today I saw a TV commercial for the movie "Fly Boys" where in the Fokker DR-1 has a demonstrated roll rate of around 400 degrees per second and the rolls are quite axle.
Having seen this I would say that the DR-1 would have given even the great A-4 Skyhawk a run for it's money.
I wonder why, with performance that good, the DR-1 didn't last that long at the front......?

I wish Hollywood would just go away.

JG1Schorner · 1 February 2007, 01:15 PM

In the trailer that I saw both the DRI and the N17 managed a vertical climb that would make an F15 proud. Of course, the DRI was reputed to climb like a monkey ...

Greybeard · 2 February 2007, 02:46 AM

Quote:

Originally Posted by Scott McGowin

...TV commercial for the movie "Fly Boys" where in the Fokker DR-1 has a demonstrated roll rate of around 400 degrees per second...

Are you kidding?

That was probably a CGI. Figure you mention is typical of jets, where control surfaces are moved by hydraulic servo-actuators operating at 500 kilograms for square centimetre! No human can develop such forces!

For a more serious report, please see NACA one, where actual value is stated around 30 degree per second.

GB

Bletchley · 3 February 2007, 04:53 AM

I don't have any original data on aileron effectiveness, but these excerpts from 'Flying the old planes' by Frank Tallman (Doubleday, 1973) might help?

Fokker E.III replica with 80 hp Le Rhone

"The warp is extremely stiff on the wings, but slight pressure and almost no apparent movement of the stick is enough to drop a wing in normal turn.. [and] ..as you pick up speed, it gets very sensitive fore and aft, and you have some difficulty not porpoising... the Eindecker series, like our modern jets, had full flying elevator and full flying rudder - in short, no fixed surfaces... the elevator and rudder are perpetually hunting and feeding the attendant changes back through the control system to the pilot"

Sopwith F1 Camel original rebuild with original 110 hp Le Rhone

"sensitive ailerons, elevators, and rudder"

Spad VII original rebuild with 180 hp Hispano-Suiza

"Spads had push-pull rod-controlled ailerons; this was a real innovation, and it gives a Spad a light feel and quick response.. [that].. is equal to or exceeds that of our present crop of aircraft.. [although].. like other early aircraft, the Spad VII control travel... exceeds anything the modern pilot is familiar with"

Sopwith Triplane replica with 165 hp radial Warner

"The three ailerons on each wing were pure delight and gave this flying club sandwich a crisp response equal to that of a Stearman or Tiger Moth"

Fokker DR1 replica with 165 hp radial Warner

""...ailerons as stiff as a boiled shirt... You very nearly need both hands for the ailerons"

The builders of this DR1 did not have access to original design drawings, and Tallman goes to comment that after subsequent modifications to the aircraft "It has infinitely better aileron control than it had originally, due to control cable relocation and alteration of aileron hinges"

SE5A original rebuild with 180 hp Hispano-Suiza

""It slow rolls to the left nicely, with about eight seconds to complete... in rolling to the right it resists strongly, and you get a roll that is impossible to do smoothly and that takes much time. Flick rolls or snap rolls were nice to the right at 85 mph but completely impossible to the left, for it stalls straight forward"

Pfalz DXII original rebuild with 180 hp Mercedes

"Control response in the air was precise, and fast on the elevators and rudders, but as in some of the spade-grip British aircraft, the aileron movement was restricted... Aerobatically it is clumsier than.. [Spad VII, Fokker DVII, SE5A].. and with a slow roll rate, only loops seem pleasant"

Fokker DVII original rebuild with 180 hp Hispano-Suiza

"The ailerons are sheer delight... all anyone could wish... the full slow roll is on the order of nine seconds"

Hope this helps

Bletchley

Greybeard · 4 February 2007, 12:53 AM

Quote:

Originally Posted by Bletchley

SE5A original rebuild with 180 hp Hispano-Suiza

""It slow rolls to the left nicely, with about eight seconds to complete...

Fokker DVII original rebuild with 180 hp Hispano-Suiza

"The ailerons are sheer delight... all anyone could wish... the full slow roll is on the order of nine seconds"

Hope this helps

Bletchley

Helps a lot, thanks Bletchley!

SE-5a: 360/8 = 45 degree per second

Fokker D.VII: 360/9 = 40 degree per second

They did worse than Curtiss Jenny (30 degree per second)!

At same time, this let understand how pilot's feelings and related descriptions may be confounding. About Fokker D.VII he starts telling "The ailerons are sheer delight..." then (OUCH!):"the full slow roll is on the order of nine seconds"!

Machinbird · 4 February 2007, 08:29 AM

Quote:

Originally Posted by Greybeard

At same time, this let understand how pilot's feelings and related descriptions may be confounding. About Fokker D.VII he starts telling "The ailerons are sheer delight..." then (OUCH!):"the full slow roll is on the order of nine seconds"!

Not confounding at all. He is referring to control forces. The D.VII must have had comfortable control forces. With the "elephant ear" ailerons offering some counterbalance, it seems reasonable.
It is no fun flying an aircraft which has control forces so high that it feels like the stick is buried in sand. An aircraft that had light control forces in one direction and heavy forces in another would also be a problem. It would be too easy to make inadvertent input in the light axis direction while muscling around the heavy axis e.g. heavy ailerons and light elevator.

Greybeard · 5 February 2007, 12:04 AM

Sorry to all,

I must correct myself: of course I was wrong about comparison with Curtiss Jenny, since it is SLOWER to roll in respect of SE5a and Fok. D7 (30<40-45 deg. per sec.).

Machinbird,

I agree.

GB