HC5A Kart build

[racket]

Hi

Really successful results for initial testing , congratulations :-)

With cutting out on fast deceleration , what happens is your pressure drops faster than your P2 pressure , effectively switching off fuel flow to the engine , you'll need an accumulator in the fuel delivery line , this allows the fuel pressure to drop slower preventing flameout .

In this pic of the GT6041 kart jetandturbineowners.proboards.com/attachment/download/208 , the vertical piece of 3/4" OD stainless tube ~6-8" tall is the accumulator , theres a checkvalve in the bottom inlet along with the main fuel valve , fuel flowing into the accumulator simply compresses the air inside , on decel. the checkvalve shuts and the air forces the stored fuel into the engine .

I think there are Bosche accumulators available .

Nice build , A/B nozzle size needs to be similar to comp inducer diameter .

Looking forward to more video :-)

Cheers
John

[ausjet]

Mar 30, 2021 2:31:22 GMT -5 racket said:

Hi

Really successful results for initial testing , congratulations :-)

With cutting out on fast deceleration , what happens is your pressure drops faster than your P2 pressure , effectively switching off fuel flow to the engine , you'll need an accumulator in the fuel delivery line , this allows the fuel pressure to drop slower preventing flameout .

In this pic of the GT6041 kart jetandturbineowners.proboards.com/attachment/download/208 , the vertical piece of 3/4" OD stainless tube ~6-8" tall is the accumulator , theres a checkvalve in the bottom inlet along with the main fuel valve , fuel flowing into the accumulator simply compresses the air inside , on decel. the checkvalve shuts and the air forces the stored fuel into the engine .

I think there are Bosche accumulators available .

Nice build , A/B nozzle size needs to be similar to comp inducer diameter .

Looking forward to more video :-)

Cheers
John

Thanks mate 👍🏻 oh I see, do you think this touchyness on decel is exaggerated by running high fuel pressures? I suppose there’s a big difference between throttling from 120-400psi than when running lower pressures. Maybe I can try a larger fuel nozzle to lower the pressure and like you said tighten the ab nozzle later which may load the engine a bit more making it the rpm drop quicker. Your accumulator is such a simple idea love it! I was thinking even like a remote res canister from a forby shock absorber but you can’t beat the simplicity and pretty much $0 cost of a bit of pipe! I’ll fab one up

[racket]

Hi

What combustor fuel pressures did you have during the test, idle and full power ??

Cheers
John

[smithy1]

Great work...nice to see another Aussie jet powered Go kart. With your A/B igniter...I tried all sorts like yours and others.... and finally went for a "hot-streak" system....works every time and is basically idiot proof.

As John mentioned, an accumulator in the upstream line to the injection will help wit "flameouts"....I have the same trouble with mine. As you've found out, slowly back on the throttle and it stays lit.

Whereabouts are you..??

Smithy.

[ausjet]

Apr 13, 2021 22:21:05 GMT -5 smithy1 said:

Great work...nice to see another Aussie jet powered Go kart. With your A/B igniter...I tried all sorts like yours and others.... and finally went for a "hot-streak" system....works every time and is basically idiot proof.

As John mentioned, an accumulator in the upstream line to the injection will help wit "flameouts"....I have the same trouble with mine. As you've found out, slowly back on the throttle and it stays lit.

Whereabouts are you..??

Smithy.

Cheers mate, where abouts do you have your hot streak nozzle positioned? Is it just like a 2mm jet pointing straight down the guts?
I’ve started building a kart lifter as I’ll end up doing my back in getting it in and out of the trailer. Then I’ll get onto making an accumulator and getting some performance numbers on paper.
I’m in Atwell, WA

[smithy1]

Apr 14, 2021 4:12:01 GMT -5 ausjet said:

I’ve started building a kart lifter as I’ll end up doing my back in getting it in and out of the trailer. Then I’ll get onto making an accumulator and getting some performance numbers on paper.
I’m in Atwell, WA

Have my hot streak is located in the combustion case, a stainless hard line going in through the lower half of the outer case and up between the outer case and the flame tube, it then bends 180 dergrees and goes in through the "hat" of the flame tube a few mm and points straight at the turbine inlet...it's a 0.8mm nozzle...2mm will be way to big. I have it running off an old VL commodore fuel pump via a normally closed solenoid and filter. I have two buttons on the steering wheel, one activates the A/B pumps, (two Bosch 044 pumps in parallel) and the other button activates the hot streak. I can manually vary the flow rates to suit what I want...they're basically just taps in the lines so I have infinite adjustability of their flows etc....

I adjusted the hot streak flow so I "JUST" get a lick of flame out the tail pipe when I hit the button. not enough and she won't light the A/B...too much and it's not real good for the turbine wheel. My pipe was modelled off Andy M's design. but he uses a different flame holder method to mine...mine is more conventional aircraftish with a proper flame holder with the spray ring up towards the turbine and flame holder several inches downstream of the spray ring...a bit of position "experimenting" is required to get the best out of them...but the results are worth it.

So I can basically do the big white cloud of unburnt fuel...or I can light it up...just like the real jet dragsters do.

Pity you're in WA....I couldn't be further away, I'm ~55km north of Brisbane.

www.youtube.com/watch?v=rd_m9fItlN0

Cheers,
Smithy.

[ausjet]

Apr 19, 2021 22:40:51 GMT -5 smithy1 said:

Apr 14, 2021 4:12:01 GMT -5 ausjet said:

I’ve started building a kart lifter as I’ll end up doing my back in getting it in and out of the trailer. Then I’ll get onto making an accumulator and getting some performance numbers on paper.
I’m in Atwell, WA

Have my hot streak is located in the combustion case, a stainless hard line going in through the lower half of the outer case and up between the outer case and the flame tube, it then bends 180 dergrees and goes in through the "hat" of the flame tube a few mm and points straight at the turbine inlet...it's a 0.8mm nozzle...2mm will be way to big. I have it running off an old VL commodore fuel pump via a normally closed solenoid and filter. I have two buttons on the steering wheel, one activates the A/B pumps, (two Bosch 044 pumps in parallel) and the other button activates the hot streak. I can manually vary the flow rates to suit what I want...they're basically just taps in the lines so I have infinite adjustability of their flows etc....

I adjusted the hot streak flow so I "JUST" get a lick of flame out the tail pipe when I hit the button. not enough and she won't light the A/B...too much and it's not real good for the turbine wheel. My pipe was modelled off Andy M's design. but he uses a different flame holder method to mine...mine is more conventional aircraftish with a proper flame holder with the spray ring up towards the turbine and flame holder several inches downstream of the spray ring...a bit of position "experimenting" is required to get the best out of them...but the results are worth it.

So I can basically do the big white cloud of unburnt fuel...or I can light it up...just like the real jet dragsters do.

Pity you're in WA....I couldn't be further away, I'm ~55km north of Brisbane.

www.youtube.com/watch?v=rd_m9fItlN0

Cheers,
Smithy.

Thanks Smithy, that videos great! Looks like you’ve got that thing dialed in 100% I’ll see how this spark plug setup goes, if if proves unreliable I’ll set up a hot streak.

[ausjet]

Hopefully a few of the issues I was having are now sorted. Rewired the thermo fan oil temp switch. It must have a solid state switch/transistor built in as it needed to be connected on the positive side.
I found a second hand suspension remote reservoir canister for $50 to use as an accumulator. Ive done some experimenting with it over the last few days. It works well with 130psi of nitrogen charge. Has slowed the pressure drop off from full throttle to idle from about 0.5sec to 5 seconds but has also obviously made acceleration just as slow. Not a big deal really. The adjustable damper valve does allow for some fill/discharge rate changes which is handy.
The afterburner 500kv spark generator arrived from China (only been waiting 3months for it)🤦🏻‍♂️ wired that up to a lawnmower spark plug with the gap opened up.
Have almost finished building the kart lifter, once that’s done it’ll be time for another test run.

[smithy1]

I'd be keen to see your kart lifter mate..??

Smithy.

[ausjet]

May 11, 2021 21:43:31 GMT -5 smithy1 said:

I'd be keen to see your kart lifter mate..??

Smithy.

Will still be a few weeks away from being finished. I’ll make a build thread in the projects section once it’s done 👌🏻

[ausjet]

Hey guys, a few bits and pieces arrived in the mail the other day 👌🏻



This is the new AEM afterburner pump It has an extra 100lph on top of the Bosch 044 which hopefully should make a difference.



And here’s the new 50a fuel pump speed controller I ordered from the UK. It has adjustable acceleration and deceleration ramps (the pots on the top). This will allow me to set the maximum the time the fuel pump takes to accelerate from 0 to 100% in say, 0.5 sec and the quickest it will decelerate 100% to 0 at 5 sec. The accumulator isn’t required now, this thing solves the flameout issue.
Just have to sort out a way to wire in a idle control. I was thinking I could try putting a pot between the 5v supply and the signal return wires on the hall effect foot throttle.

Also weighed the big girl. Came in at 169kg. No lightweight that’s for sure

[racket]

Yep , hard to keep weight from getting out of hand , my 2 shaft kart came in at 125 kgs with everything kept as lightweight as I could , LOL, a bit too light in some areas :-(

[slittlewing]

A heavy old girl but it’s built and engineered properly and to last 😁
Might be worth removing the accumulator if it no longer serves a purpose. Always handy for the pile of things that “might be useful” in future projects haha

Cheers

Scott

[ausjet]

Yep once I wire this speed controller up and it performs as expected the accumulators going back on the shelf. The afterburner adds a fair bit of weight to it. The thought crossed my mind yesterday...titanium 😁😂
Might stare at the kart with the drill and holesaw in my hand see where some more speed holes can be drilled. I don’t know if I actually need 60ah worth of battery either. Just thought yeh that’ll be plenty.

[smithy1]

Jun 2, 2021 18:59:26 GMT -5 ausjet said:

 I don’t know if I actually need 60ah worth of battery either. Just thought yeh that’ll be plenty.

I use several RC Li-po batteries to power my setup. Different voltages for different purposes. My kart only runs for ~4-5mins at a time so no need for big A/H batteries. I mainly do static engine runs at car shows and school fetes etc... certainly draws a small crowd at most venues. John and I attended a Go-kart track to show off our machines a few years back...John's engine was certainly a beast and it was a pleasure to see it run in person..!

Here's a vid of my kart at a small car show not far from Sydney a couple of years ago.

www.youtube.com/watch?v=rd_m9fItlN0

Smithy.