VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.

  #1  
Old 10-17-2014, 12:41 PM
todehnal todehnal is offline
 
Join Date: Jan 2005
Location: Kentucky Lakes area in KY
Posts: 980
Default My Fight With A Heavy Wing

I thought that my experience in resolving a heavy right wing after my build might be helpful to someone else. First, all during phase one, I was experiencing a slightly heavy right wing. After studying all of the posts on the subject, and reviewing Van?s suggestions on the subject, I decided to order the rudder trim tab, and install it first, because, the suggestions were to get the ball centered first, and mine was running a little right of center. Sure enough, after installing the trim tab, the ball was dead center, and with no adjustments to the factory bend, I might add. But, I still had a heavy right wing.

Next, it was ?pinch the trailing edge of the light wing?. I did this and it helped, but I still had a heavy right wing. The next suggestion was to take a hammer and a block of wood to the trailing edge of the heavy wing. Wow! That seemed a bit brutal, and I decided to make that a last resort effort in fixing the problem.

Next, I read where one of the builders fixed his heavy wing by taking a turn on the flapperon rod ends. I had carefully measured mine, and had put them in with Loctite, and I wasn't excited about disturbing them. I again took vary precise measurements and found my rod ends were positioning both flapperons in precise duplicate locations on each wing. Now what??

While making all of these measurements of the flapperons, I did notice a slight variation in the trailing edge of the top wing skins, where it trails past the rear spar, and approaches the flapperons. The top skin on the left wing was perfectly flat, whereas the right wing skin was drooping all along the span, just slightly; from a 1/32? to as much as an 1/16? in some areas. This was determined by extending a straight edge, chord wise on the wing skin, and seeing a slight bit of daylight under that last half inch of the top wing skin. So, I carefully reshaped the trailing edge of the right wing top skin to also make it perfectly flat, just like the left wing. The following test flight rewarded me with a beautifully flying, hands off, airplane.

Hopefully, this long post will help another builder who has been working on a heavy wing like I was.

Tom
__________________
2013- RV12, Kit #119. N123M First flight Nov21. It's a keeper!
1998- RV-9 tail kit, built and sold
1989- RV-6 tail kit, built and sold
Reply With Quote
  #2  
Old 10-17-2014, 01:38 PM
DHeal DHeal is offline
 
Join Date: Sep 2006
Location: Windsor, California
Posts: 1,006
Default

I have also noted that, as can be expected, the lateral trim of the RV-12 is sensitive to the cockpit loading (i.e., pilot-only versus with passenger, low fuel level versus high fuel level, baggage, etc.). Since much of my flying these days is me alone with about 15 gallons of fuel, I have laterally trimmed the plane hands-off for that specific flight condition. Fortunately, the RV-12's flaperons are light and effective enough to easily handle other loading conditions. And you can always turn on the SV AP to hold the wings level for you! ;<)
__________________
David Heal - Windsor, CA (near Santa Rosa)
EAA #23982 (circa 1965) - EAA Technical Counselor and Flight Advisor; CFI - A&I
RV-12 E-LSA #120496 (SV w/ AP and ADS-B 2020) - N124DH flying since March 2014 - 1,080+ hours (as of Oct 2021)!
VAF donation through June 2022.
Reply With Quote
  #3  
Old 10-17-2014, 05:21 PM
Ex Bonanza Bucko Ex Bonanza Bucko is offline
 
Join Date: Jul 2013
Location: San Diego, California
Posts: 291
Default Heavy right wing

So, I carefully reshaped the trailing edge of the right wing top skin to also make it perfectly flat, just like the left wing. The following test flight rewarded me with a beautifully flying, hands off, airplane.

Please tell me how you did that. I have an S-LSA so I can't take the airplane apart.

Thanks,
EBB
Reply With Quote
  #4  
Old 10-17-2014, 07:59 PM
todehnal todehnal is offline
 
Join Date: Jan 2005
Location: Kentucky Lakes area in KY
Posts: 980
Default

Quote:
Originally Posted by Ex Bonanza Bucko View Post
So, I carefully reshaped the trailing edge of the right wing top skin to also make it perfectly flat, just like the left wing. The following test flight rewarded me with a beautifully flying, hands off, airplane.

Please tell me how you did that. I have an S-LSA so I can't take the airplane apart.

Thanks,
EBB
I just lowered the flaps, and used a section of thin plywood, about 1' X 2'. I slid it in under the drooping trailing edge of the wing skin and gently lifted, bending in small increments until it was level. as measured with a straight edge. You will find it really quite easy to do.

Good luck...............Tom
__________________
2013- RV12, Kit #119. N123M First flight Nov21. It's a keeper!
1998- RV-9 tail kit, built and sold
1989- RV-6 tail kit, built and sold
Reply With Quote
  #5  
Old 11-12-2016, 05:21 PM
John-G John-G is offline
 
Join Date: Jan 2012
Location: Northeast Ohio
Posts: 759
Default Thanks Tom

A big shout-out to Tom for posting his observation about his RV-12 wing skins aft of the rear spar not being flat. During early flight testing, I discovered a heavy left wing and followed Van?s suggestion of flattening out the aft edge of the flaperon on the light wing (right wing in my case). After flatting the aft edge just a little, went for a test flight and still had a heavy left wing but seemingly slightly better.

Before bending more metal, decided to have a look here on the VAF forums to see what others have done. I knew the rod end bearings were set correctly, so was looking for other options. Fortunately, I ran across this thread and read where Tom discovered the upper wing skins aft of the rear spar were not flat ... and after Tom flattened them, his RV-12 flew hands off without rolling.

Decided to have a look at mine and discovered I too had places where the skins were either low or high on the same wing. The skins aft of the rear spar on both wings were tweaked to be level and that made a HUGE!!! difference ? no more heavy left wing!!

So I would suggest other RV-12 builders that have a heavy wing to first take a very close look at the skins aft of the rear spar ? drop the flaps, then adjust the skins flat using a straight edge and block of plywood using the method Tom pointed out. Fly the RV-12 and if it is still not right, then look elsewhere ? possibly getting draconian with the aft edge of the light flaperon or adjusting rod end bearings.

Thanks again Tom for bringing this to our attention.

Happy Flying,
__________________
John
http://www.dogaviation.com/

RV-12 Wings, Empennage, Fuselage, Finishing, Avionics and Powerplant kits all completed
Now Flying!!

Donation paid until September 2021
Reply With Quote
  #6  
Old 11-14-2016, 06:02 AM
rgmwa rgmwa is online now
 
Join Date: Feb 2010
Location: Perth, Western Australia
Posts: 1,675
Default

I've been scratching my head for some trying to resolve a heavy right wing. Not that it's a big problem as it just takes light pressure on the stick to fly straight, but having flown the plane across Australia and back, it's definitely annoying. Will check the skins next time I'm at the hangar. Thanks Tom.
__________________
rgmwa
RV-12LR 912ULS
120346
Reply With Quote
  #7  
Old 11-14-2016, 11:30 AM
RFSchaller RFSchaller is offline
 
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 3,168
Default

As soon as I flew off the PAPs I riveted trim tabs to my rudder and ailerons. Makes it much easier to adjust trim if you have to.
Reply With Quote
  #8  
Old 11-14-2016, 08:29 PM
rk2436 rk2436 is offline
 
Join Date: Aug 2013
Location: chicago,ol
Posts: 57
Default

You shoudnt need trim tabs to get it to fly hands off.take your time tweaking the flaperon trailing edges,a little goes a long way. No rudder trim tab here,must of had a level table some day building. She is a sweetheart!!!
Reply With Quote
  #9  
Old 11-16-2016, 07:48 PM
RFSchaller RFSchaller is offline
 
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 3,168
Default

Bob,

Glad it worked for you, but I really like the simplicity of trim tabs and they are easy to adjust if needed.

Rich
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 01:17 AM.


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.