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.


Go Back   VAF Forums > Main > RV General Discussion/News
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 01-24-2019, 02:39 PM
macrafic's Avatar
macrafic macrafic is offline
 
Join Date: May 2006
Location: Rochester, MN
Posts: 431
Default Testing - Wheel pants or not?

I did all my flight testing of our RV-7A with my wheel pants off; standard practice in Minnesota in the winter. Come spring, wheel pants back on, and retesting WOT, I found significant difference in max RPM and airspeed from my no-wheel pants testing. In reviewing the new FAA Test Flight cards, where they go into such detail as where CG should be, and how much fuel to carry, for each test, a question occurred to me.

Relative to Vx, Vy and best glide testing, would they change, depending on wheel pants or no wheel pants?

If so, I will want to retest, this time with wheel pants on. I may even retest anyway, following the FAA Test Flight instructions, just to confirm my earlier results.
__________________
Rich and Cindy Macrafic
Rochester, MN
RV-7A Flying
Reply With Quote
  #2  
Old 01-24-2019, 03:13 PM
Raymo's Avatar
Raymo Raymo is offline
 
Join Date: Nov 2014
Location: Richmond Hill, GA (KLHW)
Posts: 2,340
Default

The drag imposed by the exposed landing gear is significant and would affect glide speed and distance.

I gained around 20 MPH after installation of mine. Everything got better, including CHTs.
__________________
Ray
RV-7A - Slider - N495KL - First flt 27 Jan 17
O-360-A4M w/ AFP FM-150 FI, Dual PMags, Vetterman Trombone Exh, SkyTech starter, BandC Alt (PP failed after 226 hrs)
Catto 3 blade NLE, FlightLines Interior, James cowl, plenum & intake, Anti-Splat -14 seat mod and nose gear support
All lines by TSFlightLines (aka Hoser)
Reply With Quote
  #3  
Old 01-24-2019, 03:23 PM
AviatorJ AviatorJ is offline
 
Join Date: Feb 2015
Location: Oklahoma City
Posts: 974
Default

I plan on doing the first 5 hours without them.
__________________
Justin
RV-10, N10JW
Flying since 2/14/2019
http://operationrv10.blogspot.com/
Reply With Quote
  #4  
Old 01-24-2019, 03:44 PM
Dan 57's Avatar
Dan 57 Dan 57 is offline
 
Join Date: Sep 2018
Location: LSZF
Posts: 795
Default

don't understand how any serious testing could be done, either wheel pants off or not painted... unless it will be left as is.

Why not finish the aircraft (it ain't a new prototype, is it) and do the tests and paper filling once and for all iso a repeat
__________________
Life's short... Enjoy!

http://www.aerofun.ch

RV-6.9 #25685, slider, O-360-A3A (carb/dual Lightspeed II), MTV-12-B, HB-YLL owner & lover
RV-4 #2062 HB-YVZ airframe builder
Reply With Quote
  #5  
Old 01-24-2019, 04:07 PM
Raymo's Avatar
Raymo Raymo is offline
 
Join Date: Nov 2014
Location: Richmond Hill, GA (KLHW)
Posts: 2,340
Default

Quote:
Originally Posted by DeeCee 57 View Post
don't understand how any serious testing could be done, either wheel pants off or not painted... unless it will be left as is.

Why not finish the aircraft (it ain't a new prototype, is it) and do the tests and paper filling once and for all iso a repeat
Somewhere along the line, Vans recommended (and may still) doing the engine break-in without pants to add drag. As mentioned above, this usually only takes a few hours (5-10).
__________________
Ray
RV-7A - Slider - N495KL - First flt 27 Jan 17
O-360-A4M w/ AFP FM-150 FI, Dual PMags, Vetterman Trombone Exh, SkyTech starter, BandC Alt (PP failed after 226 hrs)
Catto 3 blade NLE, FlightLines Interior, James cowl, plenum & intake, Anti-Splat -14 seat mod and nose gear support
All lines by TSFlightLines (aka Hoser)
Reply With Quote
  #6  
Old 01-24-2019, 04:17 PM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 5,054
Default

I would definitely retest, in your situation, ensuring that both situations, wheel pants on and wheel pants off, were properly documented, and the various speeds to fly noted for each configuration.

Dave
Reply With Quote
  #7  
Old 01-24-2019, 04:45 PM
RV7 To Go's Avatar
RV7 To Go RV7 To Go is offline
 
Join Date: May 2011
Location: Ontario, Canada
Posts: 321
Default

Quote:
Originally Posted by DeeCee 57 View Post
don't understand how any serious testing could be done, either wheel pants off or not painted... unless it will be left as is.

Why not finish the aircraft (it ain't a new prototype, is it) and do the tests and paper filling once and for all iso a repeat
I believe it was recommended to do initial flight testing without the gear leg fairings or pants installed in order to evaluate the flight characteristics. Once the aircraft is properly set up, hands off wings level/ball centered then the pants and gear leg fairings could be installed. That way if the trim has changed you know it has to do with pant/fairing alignment, which can have a big effect on trim.

Al
Reply With Quote
  #8  
Old 01-24-2019, 05:36 PM
Carlos151's Avatar
Carlos151 Carlos151 is offline
 
Join Date: Jan 2008
Location: Lebanon, TN
Posts: 423
Default +1 for pants off testing

Quote:
Originally Posted by DeeCee 57 View Post
don't understand how any serious testing could be done, either wheel pants off or not painted... unless it will be left as is.

Why not finish the aircraft (it ain't a new prototype, is it) and do the tests and paper filling once and for all iso a repeat
As mentioned above, wheel pants can induce an adverse yaw if they are not installed perfectly symmetrical. If you flight test without the wheel pants then add them later you can narrow down the adverse yaw. Another reason to have weight off wheels when you align and install those wheel pants. The gear flexes inboard and changes the wheel pant alignment when airborne affecting drag and speed.
__________________
Karl Richcreek
RV-8
N151TK "La Otra Chica"
Flying as of August 14, 2015
TN26
Reply With Quote
  #9  
Old 01-24-2019, 06:31 PM
pilotkms's Avatar
pilotkms pilotkms is offline
 
Join Date: Mar 2007
Location: WARNER ROBINS, GA
Posts: 525
Default Testing done?

I started my phase 1 with no fairings or pants, for the reasons mentioned. I added fairings & pants midway thru phase 1 and retested everything. I am constantly retesting or re-verifying my results. I built this thing to fly (1.5 years flying with 250+hours) and Every time I do I?m testing or retesting something. I don?t think it?s ever DONE. Always learning.
__________________
Keith
RV 7A RV #9700 May 2017
N325KS the Flying K
Built in SoCal KCCB, now in GA @ KPXE
800+ Hours & 7X cross the USA
OSH flyin 2018 & 2019 & Petit Jean 2019 & 2021
Reply With Quote
  #10  
Old 01-24-2019, 07:20 PM
Ironflight's Avatar
Ironflight Ironflight is offline
VAF Moderator / Line Boy
 
Join Date: Jan 2005
Location: Dayton, NV
Posts: 12,829
Default

If you’re breaking in a new engine with no pants or fairings, you’re robbing the motor of significant cooling airflow -a huge deal when it comes to an air cooled Lycoming.

Just something to consider.
__________________
Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)
http://Ironflight.com
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 02:52 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.