VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #31  
Old 01-02-2018, 12:24 PM
ronschreck's Avatar
ronschreck ronschreck is offline
 
Join Date: Mar 2006
Location: Gold Hill Airpark (NC25), NC
Posts: 1,330
Default

Quote:
Originally Posted by rvbuilder2002 View Post
I don't know if it is a factor for your airplane or not Ron, but aileron shape can have some influence on max roll rate (though I don't think it would be a big difference).

If the aileron trailing edges are not properly formed with the skin profile flat along the cord line right to the tight bend radius of the training edge it will make the ailerons behave as though they were slightly narrower in cord which will also reduce there effectiveness slightly. A secondary influence is that it will also make the stick forces in roll lighter.

So if yours are not finished correctly you might get a bit more effectiveness by correcting that, but the trade off will be a slightly higher stick force.
So, correcting an imperfect aileron profile might be accomplished by pinching the trailing edges of the ailerons to more closely aligning them with that FLAT profile you are talking about??? I understand that the square trailing edges of the flight controls of most all aerobatic aircraft is done to effectively increase the apparent chord of the control surface. Is that what we should be trying to emulate?
__________________
Ron Schreck
IAC Director and National Judge
RV-8, "Miss Izzy", 2100+ RV Hours
Track Me *** Gold Hill Airpark (NC25)
VAF 2018 Donor
"He who demands everything that his aircraft can give him is a pilot; he that demands one iota more is a fool."
Reply With Quote
  #32  
Old 01-02-2018, 12:56 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 7,714
Default

Quote:
Originally Posted by ronschreck View Post
So, correcting an imperfect aileron profile might be accomplished by pinching the trailing edges of the ailerons to more closely aligning them with that FLAT profile you are talking about??? I understand that the square trailing edges of the flight controls of most all aerobatic aircraft is done to effectively increase the apparent chord of the control surface. Is that what we should be trying to emulate?
Sort of... in the case of a mis-formed trailing edge it has the opposite effect.

Page 05-10 of the current Section 5 of the construction manual has photos showing how to check it and correct it if needed.
__________________
Any opinions expressed in this message are my own and not necessarily those of my employer.

Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #33  
Old 01-02-2018, 01:23 PM
ronschreck's Avatar
ronschreck ronschreck is offline
 
Join Date: Mar 2006
Location: Gold Hill Airpark (NC25), NC
Posts: 1,330
Default

Quote:
Originally Posted by rvbuilder2002 View Post
Sort of... in the case of a mis-formed trailing edge it has the opposite effect.

Page 05-10 of the current Section 5 of the construction manual has photos showing how to check it and correct it if needed.

Thanks. I'll be checking my ailerons. I'm pretty sure I checked them during the construction phase but it never hurts to take a second look. (The construction manual sure looks nicer than the one I had when I started building my -8 in 2000!)
__________________
Ron Schreck
IAC Director and National Judge
RV-8, "Miss Izzy", 2100+ RV Hours
Track Me *** Gold Hill Airpark (NC25)
VAF 2018 Donor
"He who demands everything that his aircraft can give him is a pilot; he that demands one iota more is a fool."
Reply With Quote
  #34  
Old 01-02-2018, 02:38 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 7,714
Default

For anyone else interested, there is potential for this to have a negative impact on handle if it exists on other control surfaces as well....

A bulged control surface will make it act as if it were narrower in cord.
That will reduce the aerodynamic feedback... I.E. make the control forces lighter (possibly to a degree that impacts control ability)

It can also impact static stability. If the aerodynamic feedback force of the control circuit is lower than desirable, it has a lower working force against any friction within the system.

A small bit of turbulence or an occupant bumping the stick might induce a small movement of the system that doesn't return to the same position each time because the system feedback is too low to overcome the system friction.

BTW, this is also why friction in the pitch circuit is such a bad thing. Even if the elevators have the proper shape they wont recenter the same each time they are displaced if the friction is too high.

A mis-shaped rudder can also have a negative effect by reducing centering tenancy (once again hinging friction being a bad thing) and making the airplane appear to have reduced yaw stability.
__________________
Any opinions expressed in this message are my own and not necessarily those of my employer.

Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #35  
Old 01-02-2018, 03:19 PM
RV6_flyer's Avatar
RV6_flyer RV6_flyer is offline
 
Join Date: Jan 2005
Location: NC25
Posts: 2,996
Default

Quote:
Originally Posted by ronschreck View Post
Thanks. I'll be checking my ailerons. I'm pretty sure I checked them during the construction phase but it never hurts to take a second look. (The construction manual sure looks nicer than the one I had when I started building my -8 in 2000!)
Ask your neighbor across the street to take a look. He was at a Formation Clinic in Texas where one guy that had incorrect trailing edge bend on the ailerons and it made the airplane very hard to control in formation.

He also has a set of RV-8 ailerons that need built and could be used in the future.
__________________
Gary A. Sobek
NC25 RV-6
Flying
3,300+ hours
Where is N157GS
Building RV-8 S/N: 80012

To most people, the sky is the limit.
To those who love aviation, the sky is home.

Last edited by RV6_flyer : 01-02-2018 at 03:21 PM. Reason: add spare parts note.
Reply With Quote
  #36  
Old 01-02-2018, 03:36 PM
tracy tracy is offline
 
Join Date: Dec 2012
Location: chattanooga,tn
Posts: 172
Default

Quote:
Originally Posted by ronschreck View Post
So, correcting an imperfect aileron profile might be accomplished by pinching the trailing edges of the ailerons to more closely aligning them with that FLAT profile you are talking about??? I understand that the square trailing edges of the flight controls of most all aerobatic aircraft is done to effectively increase the apparent chord of the control surface. Is that what we should be trying to emulate?
Hey Ron, you can keep doing scientific analysis of your poor role rate, or just tie a 25lb bag of lead weight in the aft cargo shelf and fix it.
__________________
Tracy Willingham
RV-8
Pitts S2B- sold
Chattanooga, Tn
Dues Paid
Reply With Quote
  #37  
Old 01-02-2018, 05:58 PM
ssmdive's Avatar
ssmdive ssmdive is offline
 
Join Date: Jul 2012
Location: FLL
Posts: 120
Default

Quote:
Originally Posted by ronschreck View Post
I once flew Jerry Esquenazi's RV-8 and found the roll rate of his -8 to be faster than mine. Why? I don't know. I'm busy rebuilding my engine and installing a new canopy so aileron surgery would be a good project if anyone has any good ideas...
Add a second wing.....
__________________
1996 Challenger II CWS - Sold 113 hours
1974 Citabria 7ECA - Sold 211 hours
RV6 Partnership - Sold
1986 Pitts S1S - Flying
Reply With Quote
  #38  
Old 01-03-2018, 08:23 AM
dougweil's Avatar
dougweil dougweil is offline
 
Join Date: Jun 2005
Location: Hudson, WI
Posts: 225
Default

I had an interesting experience regarding this topic with my RV-7. You can read it on the Twin Cities RV Builders website:

http://www.mnwing.org/building-tips/twitchy-ailerons/
__________________
Doug Weiler

Hudson, WI
president, Twin Cities RV Builders Group
RV-4, sold
RV-7 completed and flying N722DW, 630 hours
Based Lake Elmo, MN (21D)
Reply With Quote
  #39  
Old 01-03-2018, 09:07 AM
BCP Boys's Avatar
BCP Boys BCP Boys is offline
 
Join Date: Oct 2011
Location: Kennesaw, Ga
Posts: 539
Default

Quote:
Originally Posted by ronschreck View Post
Tracy,

Where have you been hiding? You are just 80 miles from one of the finest IAC chapters in the country. IAC Chapter 3 is in Rome, Georgia. Some of the best aerobatic pilots in the country are available to teach you everything you ever wanted to know about aerobatics. Contact Mark Fullerton (markpcc2003@yahoo.com) and tell him I sent you. They are having a fly-in meeting on January 6th.

Just to be clear, no tail slides in RV's.
Tracy,
Take a quick flight down to Calhoun Ga (KCZL) . Not only we would love to meet another RV mate, but I will make sure Mark is available to meet you and you all will hit it off well, I'm sure. Mark is one of my closest friends and I know he will be excited to meet a fellow aerobatic enthusiast.

Let me know if you decide to come down.

Amir
__________________
Amir
----------
RV-7 QB - N174WM
Supporting VAF since the first visit
Reply With Quote
  #40  
Old 01-03-2018, 06:27 PM
tracy tracy is offline
 
Join Date: Dec 2012
Location: chattanooga,tn
Posts: 172
Default

Quote:
Originally Posted by BCP Boys View Post
Tracy,
Take a quick flight down to Calhoun Ga (KCZL) . Not only we would love to meet another RV mate, but I will make sure Mark is available to meet you and you all will hit it off well, I'm sure. Mark is one of my closest friends and I know he will be excited to meet a fellow aerobatic enthusiast.

Let me know if you decide to come down.

Amir
Admir, sending you email.
__________________
Tracy Willingham
RV-8
Pitts S2B- sold
Chattanooga, Tn
Dues Paid
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 01:22 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.