Svarthålet Racing - Huge pulse jet sled

[Johansson]

My friends have built a new and even larger valved pulsejet for this years Speed Weekend on Ice, yesterday they reached 2000N of thrust with it! My nostrils and ears still ache...

[pitciblackscotland]

AH yes! my favourite pulse jet

[racket]

Bigger and better ,............ thats going to be fun to ride , should have pretty good acceleration with that sort of thrust , only another couple of weeks to wait :-)

[smithy1]

Absolutely awesome Anders, maybe I should organize to come to your speed weekend, one day, maybe I should put it on my "bucket list"....that animal makes my tiny little 3" diameter Hobbyking pulse jet look rather inadequate....noisey bloody things they are.. ;-)

Cheers,
Smithy.

[Johansson]

An interesting fact is that adding the small cone at the end of the pipe instead of just a straight duct (same total length) raised the thrust with 350N.

With different sized inlet blanking plates they could fine tune the effective valve grid area along with pipe length and fuel pressure until they found a combination that gave the most thrust, pipe length wasn´t all that crucial but if they went to far opening up the valve area thrust dropped instantly.

The valve grid is working very well by the way, I believe they have only changed valved once since they built it three or four years ago.

[Jim]

I am very glad to announce that we (Svarthålet Racing) managed to meet and pass our goal of 200km/h by far!
The first run on friday wasn´t very good. 169km/h average on the flying kilometre. The track was a bit bumpy, i had problems with visibility when i closed the helmet and the Engine didn´t feel very good.
But with some hightech adjustments (duct-tape and silicone) we solved the problem with the engine power and visibility and then i just turned my brain off and held the button and went 218km/h!

And on saturday we chose another, shorter but smoother, track and went 232km/h (about 144mph)!
We gave it one last try on the longer track to chase 250km/h but then the middle Engine mount broke and damaged the Engine beyond easy repair.
So we´ll have to save that one for next year.

At least we broke Johanssons old class record of 204something.

[frankenhealey]

Congratulations!!!

[racket]

Excellent speeds :-)

Video please

[smithy1]

Wow...232kmh while sliding on ice is very impressive indeed....

Cheers,
Smithy.

[Johansson]

It runs like a true beast now, earlier it was only annoying when you stand directly next to it but now it is disturbing even to stand way back in the pits when they run. The air all around the race area is pulsating...

[Jim]

Thanks for the congratulations!

As i mentioned before 232 was way faster than we had expected from this Engine.

If you look at the thrust measurements on the old and the new Engine it just doesn´t add up.

According to them we increased the thrust with about 20% but we increased the average speed on the flying kilometre 26,5%. And that should be impossible...

This means that either we didn´t have the thrust we thought during last years run with the old Engine OR we managed to increase the thrust quite a bit when we scrapped the gasket behind the valvegrid and sealed it with silicone instead.

We will probably repair the damages to the Engine and make some static testruns with thrust measurements in a couple of weeks to find out.

We had four onboard cameras and a couple of handheld ones so we have a LOT of footage. A friend of ours is working on the editing so a nice video should be released pretty soon. But there are some clips on Youtube uploaded by spectators.

If you have Instagram you can follow @svarthaletracing. There you can find Pictures and short videos from both the building during the last couple of months and from Speed Weekend.

Oh, and there might be some Pictures of happy, drunk people celebrating

[racket]

Hi Anders

Thanks for the vid , yep , she'd be uncomfortable to be near .

Cheers
John

[racket]

Hi Jim

A 26% increase in speed at those levels is going to need probably a 50% increase in thrust .

Also once over 200kph the ram air pressure going into the engine could be making a big difference to the workings of the engine, things might be coming into "tune" .

Excellent outcome , I'll be looking forward to some more video footage :-)

Cheers
John

[enginewhisperer]

yep sounds like it might be a case of getting lucky with the tuning vs air speed, and probably a little bit of having less thrust than expected last time.

That's pretty fast for a hot piece of pipe either way!

[smithy1]

So...I guess if it goes fast enough....does it then become a "ram-jet"..??