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Post by madpatty on Apr 3, 2016 23:27:39 GMT -5
Thanks Anders.
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Post by Johansson on Apr 4, 2016 15:17:12 GMT -5
You are welcome Patty. Today I decided to make a test rig for the eddy current tachometer, I need to get the scaling right before I start the bike up again. Since the compressor has 14 blades I need a trigger wheel with a teeth number dividable with 14 to be able to find the right scaling factor, first I milled a 42 tooth trigger wheel but I couldn´t get enough rpm in the lathe for the tachometer to start registering rpm. Luckily I had a pile of old gocart sprockets so I took an 84-tooth sprocket and modified it for better trigger signal. That did the trick! I measured 1710rpm on the sprocket with the highest gearing in the lathe, that equals 1710x6=10.260rpm on the compressor wheel. The bike tachometer read 31.400rpm (+-100rpm) which is just about three times too much. Now I just need to check the Auber manual to figure out how to reprogram it correctly. I am extremely glad that I seem to have finally solved the tachometer problem, making a reliable tacho has been a constant pain in my arse since I built my first gas turbine 14 years ago.... Cheers! /Anders
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Post by Johansson on Apr 5, 2016 14:18:09 GMT -5
I managed to reprogram the tachometer so every 1.75 signal is shown as 1 rpm, now I get a reading of 10.217rpm when the trigger plate spins 1702rpm*6 (six times more teeths on the trigger than the compressor wheel) = 10.212rpm. Hooray! Cheers! /Anders
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Post by racket on Apr 5, 2016 16:27:45 GMT -5
Hi Anders
Perfect :-)
Now you'll be able to flog it right up to redline .
Cheers John
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Post by Johansson on Apr 6, 2016 3:58:27 GMT -5
Hi Anders Perfect :-) Now you'll be able to flog it right up to redline . Cheers John Yup! A really useful feature is that the "J1" and "J2" lights are programmable relay outputs, I could use them for fuel pump activation/deactivation so once I have preheated the engine and reach say 5000rpm the fuel pump is activated. This also means that if the engine flames out the fuel will automatically shut off when the revs drop below the set value. While starting the bike I need to remember to flip the fuel pump switch which is a bit tricky to do at a consistant starting rpm when done manually, having an automatic activation would make starting much easier. The second relay can be used as a runaway safety so if the revs get higher than 70.000rpm it shuts down the fuel pump.
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Post by racket on Apr 7, 2016 1:14:53 GMT -5
Hi Anders
Nice to have some "safety" attributes as well , it will be interesting to check your rpm vs P2 data now that you have a reliable tach .
Cheers John
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Post by Johansson on Apr 7, 2016 15:28:50 GMT -5
Very interesting indeed! I managed to sort the gearbox tachometer out today, I got very strange readings from it during the test run so I had to look it over. After doing some Google research I figured out that the tachometer fabric setting was to display frequency, no wonder it gave strange readings when it displayed rps instead of rpm. I set it to read rpm and made a quick test rig to check the bike tacho reading against my hand held tachometer, it was spot on. Pheww. Very satisfying to know that both tachometers are working correctly, now there isn´t that much left to do before the bike is ready for race season 2016! Cheers! /Anders
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Post by racket on Apr 7, 2016 16:14:19 GMT -5
Hi Anders
Now all you need is some fine sunny weather so you can go for a ride :-)
Cheers John
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Post by Johansson on Apr 8, 2016 14:42:02 GMT -5
Hi Anders Now all you need is some fine sunny weather so you can go for a ride :-) Cheers John Nahh, I think I´ll keep the bike off the public roads. Don´t want to piss off the neighbors with a 100+km/h run through the village... I had a day off work today so I managed to get quite a lot done on the bike project. First off I finished (except for some paint) a towing wagon that will allow me to hitch a ride behind a car back to the pits from the end of the track, I can just roll the front wheel into the cradle and keep the front brake held while being towed. I´ll have someone drive me around the village when the weather gets a bit warmer to test it out. A new and better suited glow plug had arrived in the mail a week ago so I figured it was time to try to make a kero starter that actually ignites the fuel. I made a stainless housing for it and silver soldered a thin fuel line to it. One piece of finished kero heater! If nothing else it glows like mad. I poured a bit of kero in a hose and used my mouth to blow the fuel into the kero starter while holding it with one hand and taking a picture with the other, it threw a mighty flame with no hesitation at all. Very satisfying after the smoking and spluttering from the old kero starter prototype. I just need to make a restriction and figure out a way to feed it with fuel since so little pressure is needed, if anyone know of a good way of doing it please enlighten me. Cheers! /Anders
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Post by Johansson on Apr 8, 2016 15:30:23 GMT -5
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gidge348
Senior Member
Joined: September 2010
Posts: 426
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Post by gidge348 on Apr 8, 2016 19:01:24 GMT -5
Hi Anders, That glow plug assembly looks ideal, the pump looks fine as well. My only concern is how long it would last with Kero running through it? I guess if it used in chemical labs it should be resilient and at $10 not really a big investment.
I was wondering if you could just use bypass line from the main fuel pump.
If the glow plug lights quickly and easily you could wire it in to the starter circuit and light everything at once?
Cheers Ian
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Post by Johansson on Apr 9, 2016 9:29:15 GMT -5
Hi Anders, That glow plug assembly looks ideal, the pump looks fine as well. My only concern is how long it would last with Kero running through it? I guess if it used in chemical labs it should be resilient and at $10 not really a big investment. I was wondering if you could just use bypass line from the main fuel pump. If the glow plug lights quickly and easily you could wire it in to the starter circuit and light everything at once? Cheers Ian I think it will survive, it is just a length of silicone hose that is massaged by the pump so no impellers or seals in touch with the kero. Tapping fuel from the main fuel system is a bit tricky since the main pump isn´t activated during the preheat period, so a completely separate preheat system with its own little kero tank is easier by far to build.
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Post by racket on Apr 9, 2016 17:16:06 GMT -5
Hi Anders
You will need a check valve in the fuel line to prevent P2 air being forced back through the pump once the engine is running .
The pump looks ideal for the job , a nice find :-)
Cheers John
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Post by pitciblackscotland on Apr 9, 2016 20:40:25 GMT -5
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Post by Johansson on Apr 9, 2016 23:54:41 GMT -5
Hi Anders You will need a check valve in the fuel line to prevent P2 air being forced back through the pump once the engine is running . The pump looks ideal for the job , a nice find :-) Cheers John Copy that, I guess it will bubble quite a lot in the kero tank otherwise at 3 bar P2... It´s only 6V, plus it will probably flow quite a lot compared to the hose pump.
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