|
-
POSTING RULES

-
Donate yearly (please).
-
Advertise in here!
-
Today's Posts
|
Insert Pics
|

01-09-2014, 02:13 PM
|
|
|
|
Join Date: Dec 2005
Location: Wilmington, NC
Posts: 517
|
|
For photos of how to do it, have a look at the last 8 photos here. Should you want to see how to build Panther tanks, start at the beginning.
Tony
|

01-09-2014, 03:00 PM
|
|
|
|
Join Date: Aug 2010
Location: Wichita, KS
Posts: 1,958
|
|
Quote:
Originally Posted by BobTurner
You need to use the local barometric pressure, not the altimeter setting. (close to sea level it won't make much difference)
|
The difference in two separate local altimeter settings at the same field is equal to the difference in local barometric pressure readings, when corrected to the same units of measurement.
__________________
Kurt W.
RV9A
FLYING!!!
Last edited by krw5927 : 01-09-2014 at 03:03 PM.
|

01-09-2014, 04:34 PM
|
|
|
|
Join Date: Mar 2008
Location: houston, texas
Posts: 900
|
|
Party time.
I don't want to get into the barometric pressure end of this question.
We have had some of the balloons puff-up all the sudden on us. What we have found is put a little pressure in the tank, then take the balloon and stretch it with your hands. If it is ready it will blister for you. If not put a little more gas to it and stretch it again tell it does blister. Once it is going pump it up tell it is 3/4 full and start you test. If you go to the party supply store you can pick up some thin latex balloons. They are better at blistering on up with no prompting. Odds are you have not heart your seal, but test it and be sure. Hope this helps. Yours as always R.E.A. III #80888
|

01-09-2014, 04:46 PM
|
 |
|
|
Join Date: Apr 2011
Location: Wake Forest, NC
Posts: 96
|
|
Fuel Tank Pressure
I simply used a low pressure gauge. No questions here. I filled it with 1 psi and it held for days.
[IMG]  [/IMG]

__________________
Dennis Roberts
Wake Forest, NC
EAA 1114, Apex, NC
N713DR Super-7 IO/540  SOLD
http://www.drrv7.com
|

01-09-2014, 07:42 PM
|
|
|
|
Join Date: Dec 2011
Location: Livermore, CA
Posts: 6,797
|
|
Quote:
Originally Posted by krw5927
The difference in two separate local altimeter settings at the same field is equal to the difference in local barometric pressure readings, when corrected to the same units of measurement.
|
1. Sorry, this is not correct. You only want the pressure, but altimeter settings include compensation for non standard temperature.
2. But what I really meant was that you need to use the actual barometric pressure, not corrected to sea level. That's what your manometer sees.
|

01-09-2014, 08:52 PM
|
 |
|
|
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
|
|
You guys can use what ever procedure you want to measure pressure, and use what ever pressure reference you want, but the only way to truely check for a leak is to spray it down with soapy water.
The amount of expansion or contraction of the air that will occure with even small temp changes will make you think you have a leak when you don't or maybe fool you into thinking you don't when you really do. Baro. pressure is also a factor. What if your tank slowly leaks over a 24 hr period, but the baro also drops during the same time? Your leak indicator will say you have no leak... but you do.
The balloon (or manometer, or guage... what ever you use) is not meant to be an indicator of whether you have a leak or not. It is only to help prevent inexperienced airplane builders from destroying there fuel tanks.
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.
Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
|

01-09-2014, 09:56 PM
|
|
|
|
Join Date: Aug 2010
Location: Wichita, KS
Posts: 1,958
|
|
Quote:
Originally Posted by BobTurner
1. Sorry, this is not correct. You only want the pressure, but altimeter settings include compensation for non standard temperature.
2. But what I really meant was that you need to use the actual barometric pressure, not corrected to sea level. That's what your manometer sees.
|
Altitude (pressure altitude) corrected for non standard temperature is called density altitude. Altimeter settings given in ASOS or AWOS reports, or by ATC, are most certainly NOT density altitude.
Perhaps we should start a new thread however, as this discussion deviates from the topic at hand.
__________________
Kurt W.
RV9A
FLYING!!!
Last edited by krw5927 : 01-09-2014 at 10:14 PM.
|

01-09-2014, 11:29 PM
|
|
|
|
Join Date: Dec 2011
Location: Livermore, CA
Posts: 6,797
|
|
Quote:
Originally Posted by krw5927
Perhaps we should start a new thread however, as this discussion deviates from the topic at hand.
|
Agreed; PM sent.
|

01-09-2014, 11:50 PM
|
|
|
|
Join Date: Mar 2008
Location: Seattle
Posts: 1,412
|
|
Simply put, a U tube manometer is the most accurate, simplest method to test your tank. Don't let the precision throw you off. It is so accurate that it is effected by room temperature and barometric pressure. No balloon and few gauges can approach it's accuracy.
The air volume in the column is slight, and leaks are shown very soon.
Let it sit a few days, and you will quickly get comfortable with the variations as they average out. This is amazing in it's low cost, simplicity, accuracy, safety and ease of use.
If you have good lungs, you can charge the fuel tank to 1 PSI, and almost naught more.
Tony Spicer's pictures tell all.
__________________
Scott Emery
http://gallery.eaa326.org/v/members/semery/
EAA 668340, chapter 326 & IAC chapter 67
RV-8 N89SE first flight 12/26/2013
Yak55M, and the wife has an RV-4
There is nothing-absolute nothing-half so much worth doing as simply messing around with Aeroplanes
(with apologies to Ratty)
2019
|

01-10-2014, 07:45 AM
|
|
|
|
Join Date: Feb 2005
Location: Chesterfield, Missouri
Posts: 4,514
|
|
Quote:
Originally Posted by SHIPCHIEF
Simply put, a U tube manometer is the most accurate, simplest method to test your tank. Don't let the precision throw you off. It is so accurate that it is effected by room temperature and barometric pressure. No balloon and few gauges can approach it's accuracy.
The air volume in the column is slight, and leaks are shown very soon.
Let it sit a few days, and you will quickly get comfortable with the variations as they average out. This is amazing in it's low cost, simplicity, accuracy, safety and ease of use.
If you have good lungs, you can charge the fuel tank to 1 PSI, and almost naught more.
Tony Spicer's pictures tell all.
|
All true. But it does not show where the leak is if there is one.
The soapy water test with a little pressure will do that real quick.
__________________
RV-12 Build Helper
RV-7A...Sold #70374
The RV-8...Sold #83261
I'm in, dues paid 2019 This place is worth it!
|
| Thread Tools |
Search this Thread |
|
|
|
| Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
All times are GMT -6. The time now is 01:19 AM.
|