Condensation in fuel tanks

[bones]

People, since i live somewhere there is very little humidity, i have sold an aircraft to a guy just outside Darwin, now what is the best way of try to keep water out of the tanks, while stored? :dousing:

 

Thanks

 

 

[facthunter]

condensation

 

The old method was to completely fill the tanks at the end of the day but this is not always practical. Nev

 

 

[dazza 38]

As mentioned by Nev, more fuel in the tanks, less volume left for condensation.Just have to be mindful, that if full on a cold morning etc, keep room for when the fuel expands. cheers

 

 

[wags]

Tanks should vent.

 

That's why they put vents on the tanks. Sometimes see aircraft sitting there with fuel dripping out the vent -either the aircraft is not too level or the tanks are over full.

 

 

[GraemeK]

That's why they put vents on the tanks.

Even on the kero burners!

 

Had an experience one very hot day in a 747 at LHR. While we were still at the gate, I noticed several fire trucks and men in fluoro vests milling about under the wing - and then noticed a steady stream of liquid dripping from the trailing edge.

 

We sat there for ages while they built a sand bund around what was obviously fuel, and proceeded to mop it up (subsequently confirmed by the Captain that the tanks were full for the run to Singapore, and the heat had caused expansion and overflow).

 

On taxi, as we made a sharp right turn, I reckon several gallons of Jet A1 poured out of the port wing. Same as we accelerated and lifted off, leaving a heavy spray of fuel behind us, pretty spectacular in the setting sun!

 

 

[Guest Maj Millard]

I can guarantee you it would be more spectacular if it ignited !!..................................

 

:kboom:

 

 

 

 

 

[dazza 38]

When i was in the RAAF, on my airframe fitters course,we watched this training video, about the SR71, it leaks alot of fuel when on the ground. Cant stop it, and the reason is because the airframe being made of titanium and as it heats up ,whilst flying supersonic expands alot, and cools and shrinks when on the ground.Anyway on the video to prove a point, they threw a lit match into a bucket of avtur, and the match just went out. Its a lot safer than avgas, (although the vapours are still dangerous.) Back then they didnt worry as much about the enviroment, and just let it drip onto the tarmac. Now of course, if you drop a teaspoon of fuel on the ground, their would be twenty blokes in their hazzard chemical suits running over to clean it up, and then fine you. I know tanks have vents, it doesnt mean you should fill the tanks to the brim.i did learn something spending 12 years of my life working on F111 and tornado jets HA HA. We used to have alot of leaks in the F111, we use to not worry about it to much, i mean cleaning it up. Until the enviromental things started to happen,early nineties i think from memory. Then we used kitty litter like it was going out of fashion. I think the rat catches had alot to do with it. (rat catches- slang saying for enviromental officers) . Anyway it was all good fun. Back to topic- the reason i say,not to fuel all the way full, ie- leave a little space for expansion, is that -when fuel is vented overboard, especially with mogas or avgas, creates a fire risk.

 

 

[Guest Maj Millard]

Dazza, the SR-71 actually had it's own fuel called JP7, don't know what was in it.They also had to develope a special grey rubber for the tires, as the JP7, when it leaked all over the tarmac, would destroy the normal black rubber, that's why the tires are grey. They also had to have dedicated tankers just to carry the JP7. Heaps of special stuff going on with that machine..........................................................................

 

 

[GraemeK]

I can guarantee you it would be more spectacular if it ignited

That's what my wife was thinking, I was just enjoying the view .

 

 

[dazza 38]

High major, if i remember corrrectly,as you have already said, JP7, was a bit different to JP5, i think it had different additives due to the high alltitude the a/c flew at. I could be wrong though. I remember our AVtur was a better/cleaner fuel. We didnt seam to have those big black exhaust fumes that the americans have with their JP5. Cheers

 

 

[Yenn]

You can throw a match into the filler of a petrol truck and it will fizzle out. That used to be my intro trick to new mechanics at the REME workshop i ran. To do it you have to ensure the tank is brim full, so there is no vapour in the neck. I was young and stupid then, changed now, I am old and ???.

 

Have a look at the asphalt where planes are refuelled with Avtur, in a lot of places a special mix or finish is provided to prevent softening of the pavement.

 

 

[Guest Maj Millard]

Yes the fuel nozzle and compressor technology made the jet engines burn a lot cleaner. Still some of the more powerfull current military jets, will smoke a bit when they get on them, as they are still optimized for raw (military) power. But of course nowhere near the black smoke the old 707s, B-52, and F4 Phantoms put out back then.