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.

  #11  
Old 12-20-2011, 07:57 PM
LifeofReiley's Avatar
LifeofReiley LifeofReiley is offline
 
Join Date: Jan 2005
Location: Round Rock, TX
Posts: 3,779
Default

Quote:
Originally Posted by JohnJacobsen View Post
Nobody I know that has a D-180. Looking for a steam gage Airspeed to hook up for comparison.
Stop by the airport, we can locate one you can borrow for testing. I'll email my phone #.
__________________
Reiley
Retired N622DR - Serial #V7A1467
VAF# 671
Repeat Offender / Race 007
Friend of the RV-1
Reply With Quote
  #12  
Old 12-20-2011, 08:57 PM
Tony Kirk's Avatar
Tony Kirk Tony Kirk is offline
 
Join Date: Apr 2005
Location: KDUH
Posts: 111
Default Manometer Article

One of my fellow chapter members, John McAvoy, published an article in Sport Aviation about calibrating you airspeed system using a Manometer.

Here is the link to the article and materials on his webpage http://www.iflyez.com/manometer.shtml.

Yes, his favorite building material is different than ours, but I don't hold it against him.
__________________
Opinions, information and comments are my own unless stated otherwise.
They do not necessarily represent the direction/opinions of my employer.


Tony Kirk
Van's Aircraft Tech Support (working from home)
RV-7 N777RV, AirVenture 2022 Kitbuilt Bronze Lindy Winner!
RV-6A N57TK, first flight 9/5/05...
Sold in 2011 after 725 hours of pure joy!
Reply With Quote
  #13  
Old 12-21-2011, 09:42 AM
Vac Vac is offline
 
Join Date: Jul 2009
Location: Niceville, Florida
Posts: 520
Default

John,

Take a look at this thread: http://www.vansairforce.com/communit...=static+source .

What you're discribing might be a static source pressure error. There's some other good info on this phenomenon (provided by Kevin Horton) in the flight test section. You'll still need manometer data, but if that shows the Dynon display to be accurate, then you'll need some flight test data. It generally takes some effort to get indicated airspeed and altitude "dialed in."

If you have any questions, you can drop a PM or e-mail.

Cheers,

Vac
__________________
Mike Vaccaro
RV-4 2112
Niceville, Florida

Last edited by Vac : 12-22-2011 at 09:08 AM.
Reply With Quote
  #14  
Old 12-21-2011, 10:20 AM
jjconstant's Avatar
jjconstant jjconstant is offline
 
Join Date: Dec 2006
Location: Oakland CA
Posts: 771
Default

Is your static source in the same location and using the same pop rivet head as Van supplies? Both location and shape have a strong effect on indicated airspeed. Low indicated speed implies that you may be getting pressurized air in your static source. Deploying flaps can change your static pressures at the low end if you use differing static source locations and shapes.

All best

Jeremy
Reply With Quote
  #15  
Old 12-21-2011, 10:30 AM
Bavafa Bavafa is offline
 
Join Date: Oct 2007
Location: Sacramento, CA
Posts: 3,940
Default

@ 35K, it seems like a big discrepancies

Is the airspeed off by a consistent amount or varies significantly?

You seem to have tested all but the instrument itself, so I would suggest to try to take that also out of the equation before messing more with the pitot/static system.

Of course, this is based on the assumption that the location of Pitot and static are on the suggested location by VANs. A quick check to make sure your pitot is not bent in a wrong angle, though doubtful since you have been checking every thing else.

Good luck
__________________
Mehrdad
N825SM RV7A - IO360M1B - SOLD
N825MS RV14A - IO390 - SOLD
N258SM RV14A - IO390EXP119 - Out of Paint shop & flying
Dues paid
Reply With Quote
  #16  
Old 12-21-2011, 12:30 PM
WingsOnWheels WingsOnWheels is offline
 
Join Date: Mar 2009
Location: Plano, TX
Posts: 2,333
Default

I'm not exactly close by, but I have a new airspeed indicator sitting in the box at home. If you make it up to Dallas, you are welcome to borrow it for testing. Just e-mail me if you are interested.
__________________
Colin P.
RV-6A #20603
Complete 5/10/19
PP SEL / A&P
I donate every year on my B-Day (in Dec)
Reply With Quote
  #17  
Old 12-21-2011, 05:34 PM
Walt's Avatar
Walt Walt is offline
 
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 6,717
Default

If you get up this way to pick up the airspeed indicator in the above post, stop by and I'll throw my pitot static box on it and check it.
__________________
Walt Aronow, DFW, TX (52F)

EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 2000+ hrs, New Titan IO-370, Bendix Mags, MTV-9 prop
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154
Reply With Quote
  #18  
Old 12-22-2011, 04:40 AM
JohnJacobsen's Avatar
JohnJacobsen JohnJacobsen is offline
 
Join Date: Jan 2005
Location: Taylor, TX
Posts: 98
Default

The static is pretty close to Vans location. About half an inch forward. The air speed stays consistantly off thru the speed range.

Thanks for the offer to borrow an AS indicator in Dallas. I will see what I can get done down here first.

I have access to a pitot static test set down here.

Thank you everyone for all the suggestions and offers. Hope to have this figured out soon. This is a great community.
__________________
John Jacobsen
RV7 Flying "Aluminum Falcon"
Zenith CH750 (Scratch building) SOLD
Locost 7 (Lotus 7 replica)
Taylor TX

Youtube channel: http://www.youtube.com/user/johnjaco...e=results_main
Reply With Quote
  #19  
Old 12-22-2011, 05:03 AM
NickAir's Avatar
NickAir NickAir is offline
 
Join Date: Nov 2008
Location: McMinnville, Oregon: HOME of the SPRUCE GOOSE
Posts: 540
Default

Let us know what you find out. Instrument or static system.
__________________
Tailwinds...

Simplicity is the ultimate sophistication.
Leonardo Da Vinci

Working on a RV-4
Citabria 7GCBC
Cessna 180, sold
RV7 I0-360 C/S, Slider, AP, Glass, etc. sold.
RV6 O-320 F/P, Slider, AP, Steam, etc., sold
Citabria 7KCAB rental
Piper Cherokee, sold
Sparrowhawk, sold

Proud -VAF- Supporter - Exempt, Dues Paid Anyway.
Reply With Quote
  #20  
Old 12-22-2011, 08:00 AM
Brantel's Avatar
Brantel Brantel is offline
 
Join Date: Mar 2006
Location: Newport, TN
Posts: 7,509
Default

I went thru this as well.

Take a look at this thread:

http://www.vansairforce.com/communit...ad.php?t=56387

I think like post 64 is were I found the fix....
__________________
Brantel (Brian Chesteen),
Check out my RV-10 builder's BLOG
RV-10, #41942, N?????, Project Sold
---------------------------------------------------------------------
RV-7/TU, #72823, N159SB
Lyc. O-360 carbed, HARTZELL BA CS Prop, Dual P-MAGs, Dual Garmin G3X Touch
Track N159SB (KK4LIF)
Like EAA Chapter 1494 on Facebook
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 12:15 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.