Post by Sweetenough on May 5, 2017 14:39:50 GMT -5
Hi! Have been building on a jetengine based on a B&W S500 for a couple of years now. Got it up and running just in time for speedweekend 2017! Unfortnuattly there was not so much time for chassi modifications so almost directly after the start it started to wobbel. Luckily it stopped before it tipped over. Have recieved alot of help from Mobacken racing during the build, the engine is almost a carbon copy of half of their jetkick MK3 Adding a picture just before final assembly
Post by Sweetenough on May 5, 2017 14:50:44 GMT -5
Here is some more picures At speedweekend:
Here it is equipped with a data logger for tomorrows turbine governor test. I intend to make some step response test and check the behavior of the speed controller. Tried a couple of weeks ago but the data logger created problems..... It shorted out the PWM controller so I had full power to the fuel pump at startup. Hope to have found the problem now, will show tomorrow if it works.....
Great that you´ve started a build thread for the "Jetoped" Thomas!
It is a top notch build, and with a little bit of love given to the steering arrangement it will be a jolly fun ride instead of a "shit-my-pants-full ride like it is now with the sloppy original steering wire...
Post by Sweetenough on May 5, 2017 17:12:52 GMT -5
Thanks for the kind words and for all help during the build Anders! Better late then never I supose.... Will improve the chassi/steering before next years speedweekend for sure. My driving experience was probably nothing compared to all of your adventures but still really unpleasant at the time. Next step is to fine tune the engine control, a dream for the future would be to be able to start it by a single push button. Had to exchange the EBK fuel pump since it stopped working after only about 15 minutes of operation. I guess that was the problem already at speedweekend with all of the over speed trips when trying to kickstart the EBK without fuel. Looking forward to follow the progress on all of your projects!
Thanks Racket! I'm used to be a commissoning engineer for mainly SGT-800 gas turbines. Therefore I'm just a little bit over excited when it comes to control systems 😜 The advantage to use old a ABB controller is that I know how to do the programming and it comes with a really powerful logic library, the main disadvantage is of course its size.
Yesterday was a beautiful day for some jet tests! All in all it went well, nothing broke down 👍🏻 Have a lot of data to analyze but managed improve the speed controller enough to be able to kick start the EBK! Also the temperature limiter was tested but needs some tuning. I have a problem though, from time to time it shuts down for no reason. Usually at idle. My fuel pump (Bosch 044 copy) is quite large for the fuel needed, runs on PWM control. At idle only about 1,6VDC pump voltage is needed, full speed around 3VDC. My suspicion is that the pump doesn't really like to run on this low voltages and cuts out occasionally. Ideas?
Also found a cool down fan in the "good to have stock", some silicone and silver tape later
With your fueling problem , perhaps incorporate a bleed back to tank in your delivery line so that your pump needs to work "harder".
With your"cool down fan" , if permanently mounted beware of the large pressure drop near he comp inlet , it might suck hard enough to spin the fan and possibly overspeed it , don't want bits entering the comp :-(
Post by Sweetenough on May 8, 2017 15:09:23 GMT -5
Thanks for the ideas John! Will definitely consider a return line, haven't thought that solution. Only been looking for a smaller pump but with no luck so far.
The fan is only mounted when cooling the engine. I was amazed how much air the compressor consumes, my quite larger husqvarna bts580 leaf blower gets "sucked" against the compressor at approximately 30000 rpm if not removed.
Post by Sweetenough on Oct 14, 2017 2:25:23 GMT -5
Time to start working on the improvements on the stability issues after a quite long summer break..... Have desided to exchange the original Forshaga shopper front suspension with a front end from a Yamaha phaser snowmobile. The original steering wire will be replaced with some home made hydraulic steering based on some small pneumatic cylinders filled with silicone break fluid. It is nitrile rubbet seals in the cylinders and the best fluid I could think of was silicone break fluid, any ideas on other suitable fluids?
Post by Sweetenough on Mar 27, 2019 6:50:04 GMT -5
Speed weekend 2019 done. Slight improvement from last year 83km/h to this years 93,25km/h average speed on the flying km But this year an on board computer was added to record motor data. And it has a strange behavior.... I set it up for full power at the start speed controller set to 85000rpm and fixed EBK fuel. See cursor in first chart, that is take off (you can see the cursor values in the top left) Then the rotor speed is kept at fairly constant speed(GG speed) But.... Fuel is increasing (BK fuel pressure), p3 is increasing, exhaust (T7) and TIT (T52) temp is increasing Until exhaust temperature is at 720°C where the temperature controller limits the engine (at 01:09:35 approx) Second chart is with the cursor at the end of the run just before I reduce the power
Can not get my head around why it behaves like this... Should be fairly straight trend lines after applying full power. Some limited temperature increase could be expected of course but not this massive increase in almost all parameters Ideas anyone?