P.S. Don't get me wrong. I know that some of you guys don't feel that the extra effort of building the pleated paper header is worth the effort to save $55 or so. And I can understand that (the day is coming when I might have to do that. As the kids get older I am finding far less time to go into the garage to do daddy stuff!). And I know I pointed out at least one instance of the UAT malfunctioning, but I am pretty sure that was an isolated incident or two and with the tens of thousands of UAT running hours out there, the difference in reliability between the two designs is likely a moot point. It really comes down to the money and the slight advantage with the pleated of being able to choose your own tank size. If you don't mind spending the extra cash (but trust me, it ain't buying you more reliability like some have suggested here, at least not if you build the pleated one right), then the UAT is the best solution for you. But I can not justify that since it does not take me very long to simply do it myself.

But anyway, to answer the original thread's question: "is a UAT really needed?" The answer is most assuredly NO! (but its a great solution, just not necessary).

I also want to give my 2 cents to this.

So I fly Jets now since 6 years. I have my F-22 with an AMT Pegasus and two tanks connected by an "Y" Festo Connector plus my Phantom with two JetCat P-120 and two 2,8 l Kevlar tanks not connected to each other.

Non of my planes have an "UAT" or something similar. I just use a Kavan "felt klunk" which guarantees that the Turbine gets fuel until the last drop is soaked out!

So for those who believe that the UAT is fine, OK but I think its just to silence one's conscience. I think its more important to have an accurate installation and never use resoluble
connectors on the pumps suck side.

Here in Germany also its hard to get the UAT.

I'm missing something in the translation.. Can you clarify the term 'resoluble'?

Thanks,

I think he means re-usable as in Festo...

I hope that you are using a good filter after your tank and before your fuel pump....Felt clunks have been known to shed fibers, clogging up the various components in the fuel system......[:@]

Kevin

I use home-made header tanks - round bottle 4-6oz - with the pickup/filter located rigidly in the geometric center - very similar in theory to what Erbroens described. I don't need to get rid of every last air bubble, if there is a very small air bubble in the tank, it runs around the outside of the bottle during roll-type manoeuvres. Most Jets should be flown on a scale manner - but if you are into +ve/-ve snap-type flying they usually take place at the beginning - or midway through the flight - not at the end when the fuel is low - if so then perhaps a UAT is better.
Leon

The pleated fuel filter works just as the article sez, I made my own after testing the concept by circulating fuel through the filter, no bubbles until the filter is completely out of the fuel.
Once I managed to run the UAT dry, right down to the limit of the fuel filter, due to a main tank clunk malfunction, luckily I flamed out taxiing back to the pits.

Before the pump there is a Festo Micro Filter wich guarantees that no particle at all can reach the pump!

Oh yes, I meant "reusable" but the other word was quite impressive or not

I get the feeling that this discussion is more a philosophy item. Have a UAT or not. Most of the used arguments have no technical background. Seems to me like "which car is best, BMW or Mercedes"

As I said nearly all german RC Jet Pilots never used a UAT and all these engines work fine under all conditions and also the one's I have seen with UAT did their job. So, I think its up to everybody to use the system which he feels best with.

Andreas

Thanks guys for all of the great info. This thread has been really informative, glad to here opinions on both sides.

I use the pleated filter but also just a centralized pickup in a header tank and have never had fuel bubble issues with either . On the other hand , I have seen 2 aircraft lost due to improperly purged UAT's . The bottom line is to assure bubble free fuel and my cheap header tank provides that . I never plan to burn into my header tank . I consider it unusable fuel . After a normal flight I only have a very small amount of air in the header tank that cannot reach the engine with a central pickup .The choice is clear to me .

Marc

Hey,

Nice thread, guys. This one was very informative and enjoyable to read.

I'm using a BVM UAT for my first jet, but I plan to make my own hopper tank like I did with my D/Fs before.

Does anyone use the sintered bronze filter pickup in the header tank? Does it work as well as the pleated filter?

My most recent set up in Savex L39 has two shampoo bottles for the main tanks. The second tank in the series (last one to empty) uses the clunk supplied by simjet and then into a very small hopper tank with a central pickup. This clunk will draw the last drop of fuel before allowing any air into the hopper tank. To date, I have not had any air bubbles in my hopper tank. I usually land with the second tank about half full/empty.

I think a UAT if used correctly without flaws works fine. But so does any other proper setup.

Hi Mark
I use the sintered bronze filters on all my hopper tanks....- I suppose the effectiveness depends on the micron-filtration rating of the filter!!! I posted earlier outlining my setup...cheers
Leon