Can it be done? A fixture for testing fuel tank flow under a G-load

roddie Mon Aug 25, 2014 8:36 pm

When I was building my CEF Reed Speed model.. I decided to build my own external hard-tank. There was no way to know how it would perform in flight.. That got me thinking about how I could test the tank's draw (on suction alone) under a "G" load. I didn't follow through with a test fixture.. (or even a successful flight.. Embarassed

) but lately I've thought about taking it a step further.

An engine and tank are commonly mounted and bench-run "static".. so why not build a "balanced" rotating beam-type test stand? Huh...

..

I'm serious... and I know what you're thinking.. but my idea is to have it be safe. I'm considering making something that will incorporate a simple caliper-brake (bicycle) mechanism to hold and stop the beam from rotating when needed.

An "arm" could be built to accommodate many different engine mounts, by using interchangeable modules with various beam/radial mount patterns... and the fixture would incorporate a "yoke" for tilting the rotating arm, to vary the axis.. to simulate stunt maneuvers.

Wind-tunnels are built to test aero-dynamics.. why not experiment with the effects of G-forces on our control-line fuel tanks.. before putting them in our models? I'm no physicist... but G's are G's.. right? If your tank will draw on a short-arm/high "G" load.. it should draw; out there on the lines.. I would think.

Your thoughts?

**Cribbs74** Mon Aug 25, 2014 9:06 pm

It would be great for speed, but not reliable for stunt.

I think it's a great idea!!

**RknRusty** Mon Aug 25, 2014 9:44 pm

Roddie, maybe you should contact Igor Burger of Slovakia, the current F2B Stunt world champion as of this month, who builds logarithmic control linkages for his stunters. You, he and Leonardo Da Vinci would have a great time together.

Lol Just kidding! lol!

Jason_WI Mon Aug 25, 2014 11:50 pm

you could use a really small hydraulic pump and use that as the pivot point. Add a flow control valve to limit the RPM through resistance from the pump. To measure force use an accelerometer to measure G force. Use a 3 axis digital type with an Adrino microcontroller and transmit the results through bluetooth serial connection to your PC. This way you dont need a slip ring for the wires.

Oldenginerod Tue Aug 26, 2014 3:33 am

...or you could just bolt your engine & tank to a plane and go have a good time flying!

lol!

roddie Tue Aug 26, 2014 5:56 am

RknRusty wrote:Roddie, maybe you should contact Igor Burger of Slovakia, the current F2B Stunt world champion as of this month, who builds logarithmic control linkages for his stunters. You, he and Leonardo Da Vinci would have a great time together.

Lol Just kidding!

"Logarithmic Control Linkages"? That's deep.. Shocked

Well, I appreciate the responses. I guess I'm the kind of person who feels that making something work "better".. rather than just having it work ok.. is worth some degree of thought, even if you get answers as to "why" it won't work any better.

Kim Tue Aug 26, 2014 11:44 am

I, for one, highly appreciate and applaud such pursuits of knowledge ! To that end, I've decided to employ my considerable engineering talents in designing a prototype device; intended to capture and record those elusive bits of data that may, some day, assist in answering the burning question: "WHY? " !

Designed to be worn on the left arm (please print reversed image for lefty's!), it is slid on, up to the elbow, and held in place by gripping the sawed-off broom handle near the front.

The only other accessory required is a fairly aggressive amusement park roller-coaster. Failing that, a drunken redneck, his pickup truck, and pot-holed county road will suffice.

The rest is pretty-much self explanatory.

Can it be done? A fixture for testing fuel tank flow under a G-load Red_ne10

I shall now apologize to my fellow forumers for this weak attempt at humor on a late-waking morning when I've had too much coffee and too little sleep!

**Cribbs74** Tue Aug 26, 2014 12:02 pm

Roddie,

It's a good idea, however I agree with Rod. The easiest way to test it is to put it on a plane and sling it.

There is very little risk involved if you are only flying level laps. If the engine quits you just glide in for a landing.

Ron

roddie Tue Aug 26, 2014 2:45 pm

Cribbs74 wrote:It would be great for speed, but not reliable for stunt.

I think it's a great idea!!

I guess that there are more variables to an actual C/L "pattern-flight".. that cannot be simulated any other way. Clunk-tanks for P.A... and bladders for high-G/fast-combat; pretty much assure adequate fuel delivery nowadays.

I'd still like to experiment with the idea.. for hard-tanked "speed" models; like you mentioned.

ian1954 Tue Aug 26, 2014 3:29 pm

I like the set up suggested by Kim. A marvellous implementation and solution to the original requirement!

Wouldn't it be simpler to build a fuel pump?

roddie Tue Aug 26, 2014 4:30 pm

ian1954 wrote:I like the set up suggested by Kim. A marvellous implementation and solution to the original requirement!

Wouldn't it be simpler to build a fuel pump?

As a matter of fact.. not "build" a fuel pump.. but it would be interesting to test a small 12V automotive w/s washer pump, powered by a LiPo pack in a larger model.. Huh...

The seals are rated for alcohol.. and methanol might not cause a problem. Considerations would be a regulator.. and the pump's "duty-cycle". Popcorn

crankbndr Tue Aug 26, 2014 5:12 pm

Kim wrote:I, for one, highly appreciate and applaud such pursuits of knowledge ! To that end, I've decided to employ my considerable engineering talents in designing a prototype device; intended to capture and record those elusive bits of data that may, some day, assist in answering the burning question: "WHY? " !

Designed to be worn on the left arm (please print reversed image for lefty's!), it is slid on, up to the elbow, and held in place by gripping the sawed-off broom handle near the front.

The only other accessory required is a fairly aggressive amusement park roller-coaster. Failing that, a drunken redneck, his pickup truck, and pot-holed county road will suffice.

The rest is pretty-much self explanatory.

I shall now apologize to my fellow forumers for this weak attempt at humor on a late-waking morning when I've had too much coffee and too little sleep!

I would like to order a few dozen of you first production run, make sure you include those instructions, BBBWWWWAAAAAAAAAAAAHHHHAAAAAAA!!!! lol!

sdjjadk Thu Aug 28, 2014 6:58 pm

I love the "Old School SD card" and the "Old School Data Entry Device"
You could also build and sell bolt on accessories for it such as a spring loaded engine mount and a fish type scale for use as a dyno or sell add on Lexan sleeve with a small fog machine to convert it to a wind tunnel.
Huh...