BaldEagel

Doesn't the taxi tank also need to be vented to atmosphere to allow fuel to be drawn from it?

Mike

marc s

Yes indeed and most are or should be.

marcs

Carsten Groen

Female for me and the magnet stuff looks interesting Marc!
On all my jets, I have a piece of 6mm Festo tube out of the bottom of the jets, approx 5 cm long (nice if I should do an belly landing...). I then have a normal Festo quick coupler on the 6mm tube from my taxi tank.
Works nicely, but I always gets fuel on my fingers, which then is transferred to my 18MZ's scrren [:@]

Looking forward to your ideas Marc, let us know when we can order

marc s

Will do Carsten - whats that electronic idea you were looking to discuss, PM me?

marcs

marc s

Here are the details of the 'cracking' pressure for the Festo QS valve series:

It is 0.1 bar or put another way you need to apply a vacuum of 3.6ft or around 110cm of kero to open it.

Not sure that's ideal for use on the vent side of a fuel tank in an RC jet.

marcs

Instructor

My Feedback: (16)

Slim Line made a fuel fitting that uses two O-rings to seal the filling tube. Now I know this was made to fit between the tank line and the supply line. Something just as simple but with one O-ring to seal up the header tank line when it is connected would work just fine.
Not hard to remove the header tank fitting, and the female fitting could fit flush to the fuselage.

Just thought I would throw this out there......

Larry

Turbotronic

Of course youre not sure. You have not tested it. I have for 15 years. 0.1 bar is almost nothing. As you know a fuel pump can easily collapse a strong tank with no vent. OTH hang a tube 110cm long filled with fuel from a tank to get that negative pressure. see how it makes no impression on anything.
0.1 bar is in the order of pitot pressure.

marc s

Jolly good!

marcs

marc s

Following on from the initial development I received conflicting feedback regards the suitability of 'flush' or 'tube' type options. The feeling was flush fittings would actually generate a vacuum effect drawing fuel (when it was introduced to the vent line - say went inverted) rather than generating pressure which is what is required.

As I had a little time to test I set up a small jig round at my mates workshop to see if we could test the theory.

We set up the 'flush' version first and positioned a Rizla paper just above the barb that would be inside the fuselage and connected to the tank vent port. We passed compressed air over the flush fitting and base of the fuselage to see the results. Naturally if the paper was drawn onto the barb we were likely to see vacuum being generated, and if the paper lifted away from the barb then positive pressure would be generated.

First video of the 'flush' version is here:

[link]http://www.youtube.com/watch?v=lo7Y2EJecVc[/link]

We repeated the process with a 'tube' type vent and observed the results:

[link]http://www.youtube.com/watch?v=3yJbn3chPDs[/link]

The tests show both generate a positive pressure, which is good, for me it also means that a flush fitting might therefor be a neater route to choose as this leaves the fuselage belly clear from obstructions and items which could get or result in damage and then render themselves un-usable. The MagLok system works perfectly with both the 'flush' and 'tube' versions so the product once completed field tests have been carried out will be available in both formats.

I will not be looking to introduce any 'valved' device inline with the MagLok vent fittings, this if the owners wish to introduce once released for sale this will be their choice.

FIELD TRIALS

In a departure from the normal process I am looking for 'beta' testers to try and test the system, in addition to my own jet and one Ali Machinchy will be using I am looking for 4 willing pilots to help out with testing both the 'flush' and 'tube' versions.

I would ideally like to test 2 x 'tube' versions and 2 x 'flush' versions, and in varying climate and temperatures too, so somewhere hot, somewhere cold, somewhere in Europe and somewhere in the USA would be my preference.

If you would like to help then register your interest on this thread, I will come back to those who I feel are best suited.

Here is the deal:

The MagLok fitting selected would be shipped FOC to the Beta tester

The MagLok fitting would be required to be fitted to an RC jet running a turbine where a vented fuel system is used

The jet model should be mentioned in the initial request

Fly and test the MagLok for both inflight performance and ground based 'taxi tank' connections

Testing period 3 months

Feedback directly to me via email only on a regular basis

Once trials are complete the testers keep the MagLok products

I will post any key findings and hopefully the end result will be a product which makes vent connecting quick, simple and reliable in any conditions.

Hopefully will have Beta testing samples out in the next 10-14 days to those selected.

Appreciate all the help and comments along the way.

marcs

Alex48

Hi Marc, Im happy to help although you've probably got UK covered, I have two vents for my A4 one for either saddle tank. Do you have any photos? I presume this works with your taxi tank? Once it's tested I'd like a taxi tank and two mag connectors for the A4.

Thanks, Alex

marc s

Alex, no problem mate and yes its simply a fitting which goes on a fuel line so can be used on any fueller including my Taxi-Tank which I am not sure I will make yet as the costs are high.

Pictures of the two versions (prototypes) in the thread, think on page 2, new version includes an integral barb as part of the external fitting - would you be after a 'pipe' or 'flush' MagLok?

marcs

Alex48

Hi Mark, thanks... Flush Mag locks please. Could you email md the price of the taxi tank?

Cheers, Alex

[email protected]

stevekott

My 2 cents I would say be careful on trying to generate POSITIVE pressure. From experience on my Boomerang Torus I had a vent with the same angle cut to produce Positive Pressure, I think its a holdover from the Nitro days with no fuel pump.

On a jet and a Non Kevlar tank, like the 128oz polyethylene tank, at speed the positive pressure will transfer into the tank and make the sides of the tank swell.

Now you fly your plane inverted. That vent is now on the top of the plane in an area that is in negative aeroynamic pressure and the tank is swollen with positive pressure. See what I'm getting at? The vent tube is now at the bottom of the tank and instead of air going into the tank fuel is coming OUT! A fuel Fountain!

On one flight on my Torus I noticed a large yellow stain coming back from the fuel vent. I COULD NOT clean it off. It kept getting darker with subsequent flights, specifically with inverted flights. Then I noticed some black char in one of the wheel wells. It was not a stain at all. The fuel was blowing out of the vent, being swept back to the turbine and then igniting!

I confirmed this phenomena on the ground using a leaf blower blowing from the front of the plane and then quickly flipped it over. The fuel sprayed out of the vent with about a 3" column for several seconds.

In Jets, with a fuel pump I would personally go for a system that is a neutral pressure or a very mild positive or negative. Then check it with a leaf blower on an actual airframe then flip it inverted.

I liked your piece of paper test but .. . You could easily hook up a piece of 6mm tubing with some water in it with a "U" shape ... U-Tube Manometer and easily measure pressures, positive or negative.

Just my 2 cents, Happy Flying!

marc s

Steve,

I really don't believe that the pressure (+) is very high, and even if I were to re-test using a pipe and water the results would not really prove anything as we don't have a benchmark from which to work to.

I am working on the assumption that the 'pipe' version is going to deliver the same pressure as any of the current vents being used out there in jets around the world, some file a chamfer on the pipe many others don't. I wanted to test the flush version to see if it delivered positive or negative pressure as comments suggested it would generate negative pressure which is not ideal for this application. The video showed it does infact give a similar positive pressure (in fact it would suggest slightly lower watching the paper) so I am now confident it will be fine in the real world.

Ali Machinchy is happy to test a 'flush' version, and I will test the 'pipe' version, so along with hopefully pilots from other countries testing we should be able to make sure all is 100%.

marcs

kev-o

My Feedback: (1)

Hi Marc
I'm in sunny Canada and have a ct114 tutor with twin vents one for smoke and one for the fuel system so I could maybe do one of each ? And do back to back tests.

stevekott

Marc,

I'm sure that my situation was unique. But at 150mph the positive pressure can be significant. I'm just saying that neutral or slightly negative would have prevented what I experienced below.

And granted, a modeler could always position your pipe with the slant to the side or to the rear.

Note: The vent is located far left, about an inch behind the leading edge.

marc s

Thanks to those who have requested to do some Beta testing, currently I am looking for one more pilot who is located somewhere hot like UAE or India etc.

Beta testing will be covered so far in UK, Belgium, Canada and USA.

Thank you

marcs

olnico

I can help out Marc. I guess that I qualify for "hot weather"

marc s

Oli happy to have you on-board, will be in touch.

marcs

marc s

Many thanks to those who requested to Beta test, I am always surprised as just how many are happy to step up to help out - really appreciated

Based on location these are the guys who will be testing the new MagLok system, so if you know them and fly with them please ask them for feedback.

USA - David Searles
Canada - Kevin Forsyth
Dubai - Olivier Nicolas
Belgium - Bart Gybels
UK - Ali Machinchy

We are doing a few small adjustments to the barb sizes to allow the user to fit either a large bore or standard bore pipe between the tank and the vent to cater for 0-160N or 160N + turbine installations.

During taxi mode a turbine is only likely to be on idle to say 1/4 throttle so the draw pressure is relatively small once in the air its critical to make sure the vent pipe is large enough to allow the volume of air being generated in the main tanks from fuel draw to be balanced with no restriction.

Beta kits should ship in a week.

marcs

lookilook

Great Marc, it would be nice to see pictures of the test planes and the installed position of the tubes and also some reports during the flights up to 3 months.

marc s

Hopefully all this info will be posted over the beta testing period.

marcs

marc s

I plan to 'officially' release these (subject to all the testing working out) at Jetpower 2013 in Germany during September.

marcs

kev-o

My Feedback: (1)

We have a jet event the end of the month I'm heading up there the 29th so hopefully I have the test sample for it. Looking forward to checking it out and will send pics to Marc with comments

Kevin

kev-o

My Feedback: (1)

Mine showed up so ill be installing in my carf hawk tomorrow ill send pics to Marc looks like a Slik setup though.

Kevin