RE: better UAT
 

I am currently testing a mod in the central pickup tank method adding a small Stihl filter ... the reason on doing this is that the tank could have a large bubble inside it still keeping the engine running.

Done some flights with it doing hard aerobatics and seems to work, so far. The tank is a normal du-bro like with brass tubings, and it will need only a minor dremel work at the opening because of the filter diameter.

I also don´t like festos in the fuel system.. I only use one at the fueling line with a jetcat on/off valve wich I always close after fueling.


Enrique

RE: better UAT
 

The appropriate size brass tubing inserted into a festo fitting works just fine.... Take a look under the compressor cover of your jetcat turbine for fuel and propane connections, this method has been used by several of the major engine manufacturers as a way of connecting gas and fuel.

RE: better UAT
 

Todd,
The festos on the jecat motors are on the down stream side of the pump, those will just drip under pressure. The one in question is on the suction side which will let air enter the system.
V..

RE: better UAT
 

As I mentioned before, and before, there is a "funnel shaped ramp" inside the fitting that the hose must fit, in order to create the seal. It will not seal on brass or aluminum, as the material must "form fit" itself into the seal area to create the seal. The elastic properties of polyurethane and other formulations of plastic hose/tubing is what allows this "conformal seal" to be accomplished. A flexible ring of fingers with action similar to a "Belleville Washer" retains the tubing by spring pressure. Depressing the blue colored collar flexes the spring loaded fingers and disengages them from the surface of the hose/tubing, allowing extraction.

Brass and/or aluminum tubing is not malleable enough to be formed into the required shape with just finger pressure.

Why bother chancing a leak by shoving brass tubing into a Festo fitting when numerous easily located, readily available, less leak prone, inexpensive fittings exist?
The incorrect use of some parts, like a Festo fitting, in the manner for which it was never intended, could have a dangerous and expensive outcome.
I just don't want some "newbie" to use this type of idea and have some unexpected, fiery consequences.
Either type of leak, suction or pressure, can ruin your day.

Nope, I don't have any metric brass.

Harley Condra
BVM REP
JetCat REP

RE: better UAT
 

The way I have found to stop a leak on my 6mm festo ball valve on the suction side was to insert the appropriate size brass tube into the ID of the poly tubing that goes into the valve. This enlarged the poly tube just enough to create just enough extra pressure to create a air tight seal even if the tube was immediately bent following the valve. It allows the tube to stay straight inside the festo and not deform from suction or from the bend radius. I will try to post some pics later if I get some time.


Neal.:D

RE: better UAT
 

Great idea, Undecided!

RE: better UAT
 

WOW! took almost a year to answer my question:D
http://www.rcuniverse.com/forum/fb.asp?m=4332167

RE: better UAT
 

After looking more closely at the trap i have found that the fitting is not a Festo, but another brand AND it is not for 6mm, it is actuallly labled 1/4.. Now, i did NOT use the 1/4 line that was included, i just used the 6mm i already had installed in the airframe.. Maybe if you use the 1/4 it might not leak with sideload.. Just wanting to be fair to the product , im not going to re-install it but put a UAT in there.. Russ

RE: better UAT
 

Harley,

I have never disected a Festo fitting... so I don't know about the "funnel shaped ramp". I don't even use Festo, I use Legris fittings, which funtion the same, but I can get them at the local industrial supply store.

What I do know is that I have both inserted hard plastic tubes (3mm antenna guides from the LHS) and brass tubes into these fittings... and they seal.

And like said before, even Jetcat uses a Festo fitting on a brass tube... just look under the intake cover of your engine.

Now, I'm not saying inserting something into these fittings that doesn't "belong" there is the way to go. All I'm saying is that it works for me apparently.

Hmmm, perhaps the brass only works because I use a tubing cutter? Now you've got me wondering about that.

RE: better UAT
 

The simple fact is... Brass and Tygon (appropriate size) CAN be inserted into Festo fittings and provide a positive leak free seal under both pressure and suction, Thousands of flights on dozens of planes in my personal history has proven it is extremely reliable setup.

FWIW, I do agree that keeping the Festo Quick Star fittings to a minimal on installs is a good idea. Only use what you need as Every connection is a possible failure point, the less the better.
Use what works for you.... It's all good :D

RE: better UAT
 

I think festo makes a solid plastic plug to seal off a connector? I have never had any issues with leaking 6mm or 4mm festos once they were installed.Maybe its just the way they are routed i guess. I really like that fitting on the BVM UAT suction line, it is the most positive leak proof way to connect a 6mm line.
V..

RE: better UAT
 

Harley, I'd like to know more about your procedures with the ESD lines. And are you using any Festo fittings at all?

nick

RE: better UAT
 

Here's a little more info on Festo fittings.
The more common ones we are using in our applications are the QS series.

The Festo catalog states Quote: "Standard tubing is suitable for use with compressed air and vacuum. Festo offers standard tubing in polyamide and polyurethane versions". End quote.
I read this statement to mean that plastic tubing is standard, and metallic tubing is non-standard.

Festo does also manufacture a plastic plug, but it is sized to the fitting ID.

I do realize that brass tubing is used under the cover of some Jetcat engines, and in fact, one leg of the filter in my P-180 is aluminum, and it plugs into a Festo fitting. It is machined to the correct diameter, and fits properly to maintain the seal.
The major problem that I see, is that the use of the wrong size brass or aluminum tubing will not give you the desired results without the chance of a leak. Why chance a leak?

In the USA hobby shops, how often do you see any metric sized brass or aluminum tubing? K&S is the major supplier, and I don't know...do they supply metric tubing?
Maybe it is on the shelf in Europe....

Nick,
The only Festo fitting on my new KingCat is the filler line shutoff valve. I'll post a picture of the installation and some details later.

Harley Condra
BVM REP
JetCat REP

RE: better UAT
 

I intended that only the correct size of brass tubing be used. I was not addressing it's availabilty in any way, shape, or form.

RE: better UAT
 

Yeah, I know that....you were right.
Harley