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Fuel gauge


edwardc

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Presumably you also dispense with the little mirror then Gordon, as it is just telling you what you already know? If you still use the mirror, then what is wrong with using a workable alternative, electronic or otherwise?

No... I'm merely using the mirror to verify what i expect to see. When i find that there is a difference, i can usually account for it (excessive climbing, high RPM, etc..), but if i cant, then i know that there is a problem.

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No... I'm merely using the mirror to verify what i expect to see. When i find that there is a difference, i can usually account for it (excessive climbing, high RPM, etc..), but if i cant, then i know that there is a problem.

That's my point though Gordon, you still check. I argue that if someone has an accurate and reliable alternative to the mirror, then why not accept it as a viable option? Let's face it, the little string that your mirror is tied on with could break, so it's not infallible, so arguing fallibility is moot.

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Im sure this guy is on the forum

He mentions a fuel low level light in this video and how he did it.

http://uk.youtube.com/watch?v=AjNNmhfQL ... annel_page

I think that Kev (Bendme) just uses a float switch at the 2 litre point.

Nope, he uses the gem level sensor. I emailed him then realised that he had already answered the question under the youtube video...

Ben

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We seem to have gone off subject slightly!

The thread was to build a fuel level indicator as cheaply as possible.

I appreciate Gordons concerns that we should all be aware of what we are doing in the air and that we should be more alert to our fuel consumption.

However, I need glasses to read but not to see any distance so to check my fuel I would have to get out my glasses, and try to look into a small piece of mirror at a clear fluid in a opaque plastic container and work out which 'litre' mark it was at!

The alternative is to have a LED indication as to the 'spend rate' as I fly.

I see no problem with this and at the moment, I am thinking of using 3 float or optic switches set at possibly 6, 4 and 2 litres (not decided yet) with a LED indicator for each one. The float switches would probably need a voltage stabiliser

to stop the LEDs going on and off as I fly through any turbulance.

Ben, can you let me have the RS part numbers for what you have found please.

Cheers

Eddie

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.....and try to look into a small piece of mirror at a clear fluid in a opaque plastic container ......

Mix a little Castrol TTS into your petrol first- generally helps '2 stroke' engines run better, but the primary reason for doing it is to be able to see the level in the tank when using a mirror.

Even after 3 hours in a pub, i can usually tell the level of a red liquid in a green bottle, from great distances- despite the blurred vision.

Electronics projects for electronics sake! The problem here is the weather... no one would think of doing this s**t if it were nice flyable weather....

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Here you go Eddie, http://uk.rs-online.com/web/search/sear ... breadCrumb

You might want to check with them but I think it is RS 477-4676 at £13.66. Don't quote me on that but I think it's right...

And after speaking to bendme (in the youtube vid), it is a float sensor, not optical sensor he is using. I got my oart numbers wrong. Think i'd prefer the optical anyway

Ben

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The alternative is to have a LED indication as to the 'spend rate' as I fly.

I see no problem with this and at the moment, I am thinking of using 3 float or optic switches set at possibly 6, 4 and 2 litres (not decided yet) with a LED indicator for each one. The float switches would probably need a voltage stabiliser

to stop the LEDs going on and off as I fly through any turbulance.

Ben, can you let me have the RS part numbers for what you have found please.

Cheers

Eddie

I'm still thinking of fitting a low level warning (would have got me home the other day). I already have a float switch from CPC (choose material carefully, natch).

Then using a 12v flashing LED placed into my line of vision somwhere, I get the warning. By using a 12v flasher, it keeps the component count down and and reliability & simplicity up

Today I have actually been pondering the possibility of using a 'SportVue' product to give me a HUD of RPM, CHT and altitude.

BTW Gordon, I promise you that WHATEVER the weather, I'm always thinking about stuff like this :-) It's a wonder my motor ever get's itself off the ground! :roll::roll:

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Really i'd like the Quest XC but the guys stopped making them and they are like rocking horse poo now.

I think Gilo had them fitted to the parajets that did the Everest mission...it does everything from climb and sink rate, wind speed, fuel level blah blah blah

Ben

A really good bit of kit, except the et has stopped working.

Pete b

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I went with the GEMS LS-7 single point, type 3 level switch, nylon and managed to install it much too high in my tank.

http://www.gemssensors.com/content.aspx?id=2100

It begins to flash @ half tank and to determine how low I am on fuel beyond that, I simply give the rig a shake side to side to watch the float close and the light go out as the fuel sloshes. Just as accurate as a mirror glimpse and simpler then multiple switches and LEDs (and lighter). Since I don't stare at the thing, it works well, I just didn't want to have to depend on direct visual to the tank as it's awkward and a pain in the ass.

This setup is dead simple and other than the locknut losening can not go wrong, doesn't need a control box or voltage adjustment and works on exisiting 12v.

I was kicking myself for not making adjustment for the weird shape of the tank with it's rounded bottom, but it all worked out better than expected.

Largest cost was the float switch for me. I wired it in with the strobes on the cage, although it could easily go in series with the master arm.

Stobes:

http://spectrumled.com/fixtures.htm

Scroll to:

Super Bright Strobe Light Kits

Mod required to survive paramotor vibes, but just a dab of silicone (discharge capacitor breaks away from board).

Xeon flashers have proven bulletproof 25+ hrs on cage - they are fully immersed in acrylic.

I don't think LEDs have the gumption to be seen in bright daylight for any distance compared to xeon.

Edited by Guest
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Gordon

I think you will find the primary reason for putting TTS into a 2 stroke engine is for lubrication!

However, I am worried that the fuel in my tank is'nt very red and may need some more TTS in it.

I don't think you should be flying after 3 hours in the pub either! LOL

Thanks everyone for all the tips, I will be sorting it out over the next couple of weeks and let you know how I get on.

I still think that the more indication that you have of any problem the better, just try not to rely on the leds but I will feel better having the indication that will give me a bit of time to sort out the landing.

Eddie

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putting more oil in just to make it easier to see is not a good idea, our 2 stroke motors mostly run on a 50 to 1 mix for a reason, 2 strokes fowl plugs enough as it is, with more oil you are likely to have a fowld plug more often, not only that but too much oil will eventually cause any wadding you have in your silencer to became clogged and useless.

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I have given this topic a bit of thought in the last few months. The cheapest simple method (for people like me who are not very good at electronics) I could think of is to mount magnetic reed switches on the outside of the fuel tank and have a small magnet embedded in a cork floating in a plastic tube mounted vertically inside the tank next to the reed switches. A battery, a few LED's and some wire is all that is needed to finish the gauge.

This way, making holes in the tank and the possibility of fuel leaks are avoided. All wires and electrics are outside the tank. By careful experimenting, the size of the air/fuel openings on the inner plastic tube with the cork can be adjusted so that the effects of splashing are minimised. By adjusting the position of the reed switches and their number, you can calibrate the gauge for volume and accomodate unusual tank shapes.

Reed switches are dirt cheap, as are small neodymium magnets and LEDS. If you buy in large numbers, it is possible to make a gauge for less than £20.

If anyone wants to commercialise this concept, feel free to do so but give me a concession when I buy mine :wink: .

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Hi All,

Try this, I see no reason why it shouldn't work.

bits you need from Maplin:

Box - N79BQ - £1.99

LDR - N56AY - £1.79

470 ohm resistor - M470R - 15p

Flashing LED - UK36P - 89p

Transistor - BC107B - 87p

10K Resistor - UH03D - 31p

Switch - FH97F - 1.99

9v Battery - N71BT - 2.99

Batt Clip - NE19V - 59p

Led Clip - UK14Q - 39p

Total - £11.96

lengths of thin wire to extend the LED to where you want, bell wire will do.

OK to Build:

1: work out where the battery is going in the box and fix in position with tape.

2: drill a hole in the box so that the LDR is flush with the outside. The LDR wil look into the fuel tank where the level is.

You can fix the box anywhere you want on the tank..

3: construct the circuit.

4: Extend the LED to wherever you want - remember the polarity.

5: switch on and adjust the 10K pot so that the LED lights when the fuel level drops below the LDR.

Here is the circuit.

tranldr2.gif

OK How it Works:

LDR won't allow current to pass when there is no light falling on it, i.e. its covered by fuel.

When the fuel level drops and light falls on the LDR, current passes, which turns on the Transistor.

When the Transistor turns on, it allows current to flow through the LED.

You adjust the 10K pot to set the sensitivity of the LDR ie when it switches on.

Disclaimer:

I haven't built this yet, but its so simple it should work and for £12 it'll be fun tinkering about with it :D

and if it fails.... use a mirror!

I'll probably build this in the new year, so I'll let you know how it goes.

Have fun.

Woody

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