Acro Image

Aerobatics Server

ACRO E-mail Archive Thread: Pitts S1S Roll Rate

[International Aerobatic Club] [Communications] [Aerobatics Images]

Disclaimer: These aerobatics pages are developed by individual IAC members and do not represent official IAC policy or opinion.

[Usage Statistics]


ACRO E-mail Archive Thread: Pitts S1S Roll Rate



                


Thread: Pitts S1S Roll Rate

Message: Re: Pitts S1S Roll Rate

Follow-Up To: ACRO Email list (for List Members only)

From: Allan Franko <allanf at cancerboard.ab.ca>

Date: Tue, 11 Mar 1997 22:18:25 UTC


Message:

  I'm very satisfied with the Falcon ailerons manufactured by Jeff Paulson (E-mail me 
directly if you want his address).  The extra bay and symmetrical shape give a 
substantial increase in roll rate over the original asymmetrical ailerons on my 
S-1S, without spades.  How much extra?  I haven't tried to time it, but with the 
original ailerons and gap seals I had difficulty capping off a one and a half or a 
4-point vertical roll without sagging, with a 4 to 6 g pullup from the 150 mph 
indicated maximum airspeed at the 5000 to 6000 foot density altitude that I usually 
encounter in practice.  This made Unlimited sequences nearly impossible for me.  
The Falcon ailerons solved this problem completely.

Without spades, I think that the stick forces below 150 mph are similar to those of 
the original ailerons without gap seals.  Above 150 mph the ailerons stiffen up a 
lot, and at 180 mph it takes more force to get full deflection than I am willing to put 
into the drive mechanism.  However, no Unlimited compulsory for at least 8 years 
has required rolling at high speed, so I don't think that this is a problem, whereas 
eliminating spades is a major advantage.  Other people using these ailerons have 
installed spades, and I'm not sure why.  One possible difference is that I retained 
the wing-tip bows.  Another is that I spent a lot of time making the aileron coves 
conform to the shape of the leading edge of the ailerons, so I have no more than a 
1/16 inch gap throughout the coves.  This might be equivalent to gap seals, which 
reduce stick forces substantially in some applications.

Additional details on these ailerons:  three hinges; all wood, plywood covered 
(about three times as heavy as the asymmetrical ailerons); blunt trailing 
edges; slave strut directly behind the I-strut (Jeff claims a drag reduction, but I think 
the main advantage in a cleaner appearance - the stock Pitts has too many wires 
and struts at odd angles to each other).  My set has been trouble-free for about 200 
hours of Unlimited practice.

Allan Franko



On Mon, 10 Mar 1997 08:47:15 -0600 YYZ wrote:

> From: YYZ <larrwill at postoffice.ptd.net>
> Date: Mon, 10 Mar 1997 08:47:15 -0600
> Subject: Pitts S1S Roll Rate
> To: IAC <iac at harten.cbu.edu>
> 
> Has anyone ever heard of a symmetrical aileron mod for the Pitts S1S,
> or any great ideas on how to increase roll rate. 
> 
> Thanks,
> larrwill at mail.ptdprolog.net




                


© Dr. Günther Eichhorn
Retired
Email Guenther Eichhorn