ScottsCrazyBuilds Jet Kart

[slittlewing]

The old kart fuel system has now been removed, had a little wait for some new parts from China. The 044 outlet is now converted to 6AN, along with a new 30 micron filter of the same type I used on the Jetbike.

I have a pressure gauge on the outlet and a 3D printed piece which holds a potentiometer (bench test throttle) and 4 segment display so I can correlate fuel pressure against P2 and PWM for future ECU software.

I am using a “spare” old Jetbike ECU to provide the high side drive and computation, saves on costs and time.





mnworks

At the moment this makes the control systems a bit of a lash up from my perspective (one mini ecu for 18.5V AB pump, one for 12V main pump) but it should enable further testing and hopefully more reliable running.

Cheers

Scott

[Sweetenough]

Hi Scott,
Will you be running the pump in pressure control or just PWM?
Hope to see it running soon and hopefully also hear that AB roar

Kind Regards
Thomas

[slittlewing]

Hi Thomas,

Many thanks - I operate all the engines in open loop on the main fuel pump. The fuel circuit resistance to flow should always be a constant and repeatable, although I compensate for decreasing battery voltage on my Jetbike v2 ECU (with respect to idle fuel setting).

I closed the loop on oil pressure control on jetbike but not so far with the kart until it goes to a proper new ECU design. I got around this by putting the VESC into torque control (aka pressure control). However the oil pressure switch remains functional to kill fuelling if required.

Cheers
Scott

[Sweetenough]

Thanks for sharing Scott,
Good luck with the upcomming testruns!

Kind Regards
Thomas

[monty]

May 24, 2022 14:14:47 GMT -5 slittlewing said:

I closed the loop on oil pressure control on jetbike but not so far with the kart until it goes to a proper new ECU design. I got around this by putting the VESC into torque control (aka pressure control). However the oil pressure switch remains functional to kill fuelling if required.

Scott,

I am using a Vesc to control my fuel pump too. I'm fairly certain I could actually program it as an engine controller, but the documentation is a bit.....sparse. Especially on the canbus side of things.

I actually have 3 vesc controllers, one for the starter/generator, one for the fuel pump, and one for the oil pump. I'll use torque control for the oil pump. The starter/generator can provide the rpm signal. I'll use some kind of Canbus daq to post temps and pressures.

I would need to use canbus to get them all talking and sharing data. Unfortunately.....Github insanity...

Monty

[slittlewing]

Hi Monty,

The Vesc’s are great but I think you are probably making your life quite difficult for yourself trying to use them in this way. It would be much simpler to use an arduino as a “master” to drive the 3 Vesc’s as “slaves” via PPM (servo output). Easy to code and tonnes of support online. You could alternatively use CAN with the arduino if you are happy tackling the increased complexity.

Cheers
Scott

[slittlewing]

Hi All,

A video of the new returnless fuel system driven by old Jetbike ECU. Nice stable fuel pressures now 



Cheers

Scott

[wannabebuilderuk]

May 29, 2022 5:54:35 GMT -5 slittlewing said:

Hi All,

A video of the new returnless fuel system driven by old Jetbike ECU. Nice stable fuel pressures now 



Cheers

Scott

"I paid for the whole gauge I'll damn well use the whole gauge" lol

[slittlewing]

Hi All,

Perseverance pays off…!



Engine now running smoothly and AB rock solid.

Looking forward to more tuning 😁

Cheers

Scott

[monty]

May 29, 2022 5:49:25 GMT -5 slittlewing said:

Hi Monty,

The Vesc’s are great but I think you are probably making your life quite difficult for yourself trying to use them in this way. It would be much simpler to use an arduino as a “master” to drive the 3 Vesc’s as “slaves” via PPM (servo output). Easy to code and tonnes of support online. You could alternatively use CAN with the arduino if you are happy tackling the increased complexity.

Cheers
Scott

Scott,

That is actually what I'm planning to do. There is a company in the US that makes an industrial strength Arduino. That is the board I'm going to use.

How did you implement your PWM, just a VESC controlling EFI pumps? I'm building my fuel and oil pumps and using motors that are typically used on E-boards.

Awesome video with the AB BTHW! How much thrust do you think you are making?

Monty

[ausjet]

Jun 4, 2022 7:42:21 GMT -5 slittlewing said:

Hi All,

Perseverance pays off…!



Engine now running smoothly and AB rock solid.

Looking forward to more tuning 😁

Cheers

Scott

Congrats Scott! Betcha that would have put a smile on ya face all week, looks like you’ll need a bigger fuel tank!

[racket]

Hi Scott

Ready to start turning those tyres :-)

Evolution is progressing nicely as both Andy and myself hoped it would with your input .

The engine has performed much better than both of our initial expectations , it was a radical design that fired up and "worked" , but as with all engines theres going to be "improvements" that can be made with the benefits of hindsight ..............heh heh , I've spent years, and with a lot of dead parts, on my engines getting the gremlins out of them , as do the full sized aero engine manufacturers when we read their Papers .

The 10/110 is a good matching of readily available rotor parts , and considering you've run it up to well past its design 3.5 :1 PR ( 2.5 Bar P2) without any problems , the basic design appears to be sound :-)

Looking forward to the kart breaking records :-)

Cheers
John

[praendy2203]

Hi Scott,

nice, the camera is shaking after a/b ignition.

Stable run👍 congrats from Germany!

I hope during the next runs, you will cover your ears. I guess, its a bit loud😁

Andy

[Sweetenough]

Hi Scott,
Congratulations!
Perseverance is the key to success as you state!
Good luck with the comming speed trail, looking forward to see what it can do.
Kind Regards
Thomas

[slittlewing]

Hi Gents,

Thanks for the comments! Really pleased with the results of this test and the progress.

ausjet - cheers haha, bigger fuel tank defo required!! I have a plan! She’s certainly thirsty!! 🌊

Monty - In the test above I am controlling no Vesc’s with arduino (vesc stand-alone with a servo “tester” off eBay) but I will move to controlling it with arduino you just need 5v, ground, and a digital out pin using the servo library. Thrust will be measured soon! I am controlling 2 EFI pumps in the test above using one arduino mega on an old jetbike ecu and one arduino uno on a universal board I built. The high side drive is on the pcb and my design that I have tweaked to now work between 12 and 24v. 

John - spot on, the matching of components and NGV etc seems optimal, so full credit to you and do AndyMs designs! The fuel injection system seems great too. All I have really done is “massaged” a few bits to my liking or thoughts, and added some electronic controls. I hoped when buying the kart that this would be the case, I obviously have more to offer in the controls area than to anything related to turbine design fundamentals 😅

Andy - Thankyou, don’t worry I was wearing earplugs the whole time!! It is bonkers loud even just to spool. In one test I wore ear defenders instead and one somehow came Unclipped, it was painful!!

Thomas - many thanks, hopefully a shakedown at some point soon but more static testing and tweaks are needed first… if I take it rolling I want to be sure it is 100% so as not to waste a days trip as it’s not likely to be cheap! 🤣 🤞

Cheers

Scott