VansAirForceForums  
Home > VansAirForceForums

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

- Today's Posts | Insert Pics

  #21  
Old 04-16-2016, 12:15 AM
jwilbur jwilbur is offline
 
Join Date: Dec 2010
Location: Culpeper, VA
Posts: 630
Default

Quote:
Originally Posted by WrightsRV7 View Post
For what it is worth, on my RV7, I ran mine (Dynon set-up) back with the wires going to the tail and mounted in on the rear inspection panel under the HS. ... .
Thanks. I think I may give this position a try.
__________________
-Joe Wilbur (N520LW)
Phase II - 11/2017
First flight - 8/2017
RV-10 Build Log
Reply With Quote
  #22  
Old 04-16-2016, 06:02 AM
Weasel's Avatar
Weasel Weasel is offline
 
Join Date: Dec 2012
Location: Brooksville, MS
Posts: 718
Default

Just another data point. I put the OAT probe in the bulkhead under the rear tail fairing.

The tail area is an area of higher pressure and the small amount of air that leaks in around the elevator horn opening is migrating forward (past the temperature probe) in the fuselage towards the area of lower pressure (cockpit).

By testing multiple times I feel it is as accurate as I need it.


Flying a 3 way gps run with Kevin Horton's spreadsheet calculations shows my TAS within ~1 Knot of the calculated TAS on the efis which uses temperature.

Additionally when in the clouds and the OAT slowly drops to ~34-35 deg F I start picking up light ice on the wings and windshield which is what I would expect.
__________________
Weasel
RV-4 715hr Sold
RV-10 "School Bus" - +1400hr counting
Fisher Classic Cassler Power VW sold
RV-10 N7631T 820hr Sold
RV-8 700+hrs
Carbon Cub 200 hr Sold
One-Off Super Cub 90 hr
SERFI AWARDS

http://weaselrv10.blogspot.com/
Reply With Quote
  #23  
Old 04-16-2016, 06:19 AM
N427EF N427EF is offline
 
Join Date: Oct 2005
Posts: 1,510
Default Rear NACA

With a dual Dynon set up I have 1 each installed in the left and right rear NACA.
An additional one is located inside the wing root mounted through the
fuselage wall serving my EI engine monitor.
For comparison, I see very little difference between any of the 3 probes in flight. 2 or 3 degrees difference showing up when flying north and the afternoon sun hits the one side of the airplane more than the other.
__________________
Ernst Freitag
RV-8 finished (sold)
RV-10 Flyer 400 plus hours
Over 2500 Gallons of E10 mogas burned
Don't believe everything you know.
Reply With Quote
  #24  
Old 01-31-2018, 04:11 PM
sglynn's Avatar
sglynn sglynn is offline
 
Join Date: Mar 2008
Location: Anacortes, WA
Posts: 652
Default OAT Probe Location

Quote:
Originally Posted by WrightsRV7 View Post
For what it is worth, on my RV7, I ran mine (Dynon set-up) back with the wires going to the tail and mounted in on the rear inspection panel under the HS. Seemed to give good numbers and not affected by exhaust (i.e. never saw change with power setting changes, attitude, etc..). Very small gage wire so weight etc is no factor. Always seemed to provide accurate true airspeeds as well, to me a very nice benefit of having an OAT hooked to a glass cockpit. Not sure if I could "spin the dial" and get a true airspeed anymore, clearly spoiled by Dynon. Plan on the same location for the 10 I'm building.
Hi, please just to clarify your OAT probe location. I'm mounting mine now for Dynon D10. Are you saying you mounted it out of any air stream and inside the area under the vertical fin? I like it. Seems like this is a perfect location. It would measure air temperature with no affects from any wind warm or cold. Right? Is it a good location?
__________________
Steve Lynn
RV-7A
95% Complete
Ready for first start
Anacortes, WA
www.mykitlog.com/sglynn
Reply With Quote
  #25  
Old 01-31-2018, 04:19 PM
RV8JD's Avatar
RV8JD RV8JD is offline
 
Join Date: Jan 2005
Posts: 885
Default OAT Probe Location

Steve,

Here it is on my -8, under the Horizontal Stab. Many have located it in this location, or on the inspection panel a little further aft (probably like "WrightsRV7"). Seems to work well.

__________________
Carl N.
Arlington, WA (KAWO)
RV-8, 400 Tach Hours
(Pic 1),(Pic 2)
- Out with the Old, In with the New
(Pic)
RV-8, 1938 Tach Hours (Pic 1),(Pic 2) - Sold

Glasflügel Standard Libelle 201B, N564NS - Sold
Rolladen-Schneider LS1-f, N61MP - No longer owned

Last edited by RV8JD : 01-31-2018 at 04:27 PM.
Reply With Quote
  #26  
Old 02-02-2018, 02:42 PM
mdaniell mdaniell is offline
 
Join Date: Oct 2009
Location: Albury, NSW, Australia
Posts: 15
Default

I mounted mine on the right fuse just inside the leading edge wing root cover. There seems to be enough gap to get airflow, and on the right side so on the downswing side of the propeller. Easy routing, it's protected and in the shade when parked. Seems to be consistent with all other available temperature information such as TAFs, AWIS and ATIS.

Martin
Reply With Quote
  #27  
Old 02-02-2018, 10:47 PM
bhoppe2 bhoppe2 is offline
 
Join Date: Apr 2013
Location: nolensville, TN
Posts: 21
Default

I had the same question during my build about where to mount the probe. By searching this forum, I learned that many people have found a variety of wrong places to place the OAT probe. For example, I learned that installing it in the NACA scoop may look cool, but reads hot. Garmin says put it on the underside of the wing. Get it away from the engine and air disturbed by the prop. It should be in the airstream. It is also in the shade on the bottom of the wing, unless you are upside down, which is not recommended in a RV10! Cut, then splice the cable after you have it mounted - not difficult. The Garmin manual says the cable can be extended up to 25 ft. I did not see any reason to reinvent the wheel, repeat mistakes made by others, or over-think it. However, they are experimental aircraft.
Reply With Quote
  #28  
Old 02-03-2018, 02:04 PM
larosta larosta is offline
 
Join Date: Dec 2010
Location: Redlands, CA
Posts: 137
Default

With regards to mounting the temperature sensor in the NACA inlet. My first reaction is that by design the inlet has some compress-ability in the throat or slightly forward of that area. As we know the gas law tells us that increased pressure comes with increased temperature.

It would be interesting to block the outlet of the scoop and see what the temperature differential is compared to a wide open outlet. Low speed - small variance, high speed - probably increased temperature relative to the OAT.

Just a thought on other factors that may be causing the errors besides engine thermal sources.

-larosta
Reply With Quote
  #29  
Old 02-03-2018, 04:28 PM
N941WR's Avatar
N941WR N941WR is offline
 
Join Date: Jan 2005
Location: SC
Posts: 11,532
Default

On my -9 I mounted both on the rear bulkhead, under the empanage fairing. It reads high o the ground but once air starts moving through that area, it is always within a degree, high or low, of people I fly with.

The reason I mounted it there was to keep me from hitting it when I wash the plane.
__________________
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
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 11:36 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.