In Sweden we call it a kick...

[Johansson]

Hi guys!

Thought I should tell you about one of the projects I am involved in right now, we have been at it for two years now but this year we have hopefully sorted out most of the gremlins in the engine.



The engine is built around a Schwitzer S500 turbocharger from a marine diesel engine, it starts and runs on diesel thanks to a combined spray/vapour tube combustor.



An IC engine powers a hydraulic pump that acts as the oil pump, a homebuilt Arduino engine management system runs the pumps by PWM controlling and monitors all the temp, pressure and rev data and displays them on a LCD screen. We can even send the data live wireless to a laptop so one of us can check the temps and so on while the engine is running.



The calculated engine data is as follows:

Comp inducer: 80mm

Comp exducer: 115mm

Turbin exducer: 90mm

Turbin inducer: 100mm

146.1°C T2 at 3.2PR.

170.3hk is consumed by the compressor at 3.2PR

TOT is 655.6°C

Jetpipe PR is 1.53

The core engine consumes 1.01L/min

The afterburner consumes 2.79L/min and produces 39% more thrust which gives us 52.2kg of thrust.

The exit velocity from the afterburner is 611m/s



That was a pic of me through the flametube, you can see the three vapour tubes in there as well. Below is an illustration of what we believed a runaway would look like...



Our first test run, only idling in this clip but we could still see that there were potential in the engine. The vehicle is called a "kick" here in Sweden, old ladys use them to go shopping in the winter. The IC engine could use some tuning by the way...



After this run we did some final mods to the fuel system and ran it again to test the afterburner, we were in a bit of a hurry since we were going to race at the annual Speed Weekend on Ice a couple of week away.



We loaded the kick along with a couple of pulsejet vehicles and went to the race, unfortunately we lost oil pressure during the race and ruined the bearings. For this years event we have rebuilt most of the engine so it won´t happen again, the race is set at 11-12 march so we have some time left to get it sorted out.

Here is a video of last years event, I will get back to you with more videos as soon as we get the engine back together.



Cheers guys!

/Anders

[ernie wrenn]

Now that is WILD!!! Love it... IS that real snow or was it imported? It has been 70 to 75' F. here is South Carolina. USA.

How fast were you running?

Richard... Inline skates.... This is YOU!

Ernie

[racket]

Hi Anders

She's looking good :-)

Can't wait for you to start doing some actual thrust tests and getting "numbers"..............it'll be an interesting Thread .

Cheers
John

[Richard OConnell]

Sounds like a lot of fun but you would probably have to wait fot the snow to come back after each pass

[Johansson]

Real snow in the clip, yesterday when we were helping a fellow racer to get his Boeing 553 powered Lamborghini going it was -19°C so there is no shortage of natural snow around here...





The kick grinded to a halt 50m before the first speed trap at the race so we never got a speed reading, even if we did it wouldn´t have been much to talk about since the afterburner had flamed out just after the start and refused to relight.

I will get some numbers for you John once we get it together again.

[Johansson]

Here is a clip from yesterdays testing, we spent 6 hours correcting messed up wiring for the electronic fuel box so there was not enough time to sort the afterburner out.



The problem is that there is no way of controlling the fuel pressure over the six 1mm afterburner injectors, it is either no pressure or full pressure from 3 Bosch EFI pumps.

One of the team members will build a PWM controller for the pumps along with a better ignition so the owner can ignite the AB at low fuel flow, we experienced similar problems with out jet kick so I am confident that we will solve the problem soon.

This had nothing to do with our kick, but I figured that you would find it interesting anyway. ;D

[ernie wrenn]

What motor are you running?

Looks like the hot streek is not coming on and sounds like the tail pipe opening is to small..

Ernie

[Johansson]

Do you mean the engine in the kick or in the car?

The car engine is a Boeing 553 converted for thrust and the homebuilt afterburner use a spark plug to light the afterburner fuel, after some tweaking it should work ok. The AB nozzle on that engine should be spot on if the numbers are correct, we´ll see what TOT we get once it lights up.

The kick engine is a real screamer with the afterburner lit, but TOT is still acceptable so I don´t think that the jet nozzle is too small.

[Richard OConnell]

On the car, I would think you might have trouble getting the afterburner to light and stay lit using a spark plug. Although it works in some applications, in my reading, I have found others to be problematic. If you continue to have issues with the burner, you might consider using the method that me and Ernie used to start the engine inside the Hearse. jetandturbineowners.proboards.com/index.cgi?board=projectsboard&action=display&thread=12&page=2 It adds more clutter and components to your rig, but its a good, reliable way of getting it lit.
In any case, good luck with your project. It looks impressive and I cant wait to see more

[ernie wrenn]

Johansson

Have you tried using a "Hot streek" to light the A/B. by inserting a raw burst of fuel in the burn can, you can light the burner at full pressure. The Steek on the S-10 and hearse are picked up off of the main fuel line to a solenoid using a timer to control the amount of fuel used.

Our timers are set at .03 of a second using 1/4" line to the burner can. At full throttle and all pumps running we deliver approx 15 gallon a minute to the A/B with no ignition problems.

With Chris Krug's help we finally got it worked out, then decided more fuel, bigger booms.

The mention I made on the tail pipe comes from a LOT of testing on exhaust cone sizing. With the R/R 201 we started at a 10 inch (engine would not start due to back pressure).

12 inches took a long start time with low rpm and built a high egt temp. due to compressor back pressure.

14 inches Easy start good runs but had a problem with high rpm and A/B use. The engine would drop 2000 rpm's and egt would climb to 850 c .

16 inches.. Easier start. Picked up 3500 RPM's, lower EGT's total rpm 14,500 with NO drop on rpm's with A/B running. EGT 750c . Major improvement on power and easy rapid burner pops. (2 to 3 per second @ full power).

Jet blast to the rear increased 25% with no strain. I have a short video I will up load that was taken by a local TV station and newspaper. I will put it on another mssg.

Ernie

[ernie wrenn]

Here is the video. I was given approx 3 seconds to come up with the truck info so there are a few inconsistence answers, but you get the idea.

Ernie

www.youtube.com/watch?v=H6hvCvvZluc&feature=mfu_in_order&list=UL

[Johansson]

Thanks for the summary on jet nozzle sizing Ernie!

On this particular engine the eye might be fooled since the afterburner diameter is a bit on the large size, it was deliberately oversized/over-volumed because the owner has neither the experience or equipment to make changes to it once it was delivered to him so it had to work directly.

That is also the reason why I won´t suggest hot streak ignition to him, it is a great idea but only of you know exactly what you are doing.

The Boeing 553 engine produced 500hp with the power turbine fitted and will deliver somewhere around 200kg thrust with afterburning, not much for a 7-800kg car so he will need every single kilogram of thrust to get a decent speed out of it.

The jet nozzle is 15cm in diameter.

[Johansson]

Nov 29, 2010 17:35:07 GMT -5 Richard OConnell said:

On the car, I would think you might have trouble getting the afterburner to light and stay lit using a spark plug. Although it works in some applications, in my reading, I have found others to be problematic. If you continue to have issues with the burner, you might consider using the method that me and Ernie used to start the engine inside the Hearse. jetandturbineowners.proboards.com/index.cgi?board=projectsboard&action=display&thread=12&page=2 It adds more clutter and components to your rig, but its a good, reliable way of getting it lit.
In any case, good luck with your project. It looks impressive and I cant wait to see more

Thanks for the praise!

That igniter looks very interesting, have you tested how well it will ignite when there is a rapid flowing jet of air going past the tip creating an under-pressure in it?

As I wrote to Ernie I don´t think that a hot-streak ignition is the right choice for Bosse (the owner/builder of the car) since he has very little experience of gas turbine operation and I live too far away from him to be of any assistance to him.

I´ve thought of another way of igniting the afterburner if everything else fails him, that would be to operate the afterburner during startup when the secondary fuel stage starts and flames are coming through the turbine wheel. That would practically be hot streak ignition without having to modify the engine in any way, no good for show bursts but if he keeps the car turned off until it is his turn to race it should work.

Great videos there Ernie, I´ve been thinking of buying a Viper engine for a while and those videos didn´t exactly give me other ideas... ;D

Anyone that wants to part with a Viper engine just let me know.

[ernie wrenn]

I have got 6 of them from 201's to 522's. The easiest engine to work with .

My afterburner has 2x 1 inch stainless tubes with .080 wall, drilled with 60x .125 holes in a 45 degree pattern on each tube. The tubes are mounted in a X pattern with a slip assembly for expansion during burn. Also there is a 1 inch "lolly pop" ring tube with 50x .135 holes mounted in front of the X bars.

I push ALL the fuel I can make through the A/B with the 16 inch opening with NO problems.

Could using the start up system cause a hot start? A flame inside the engine is a BITCH... Been there...Done it!

I am not familiar with the Boeing/Walther series.. just thinking safety .

How about a hot streak using a "momentary" contact switch or spring loaded switch to off? Forget the spring load switch, he might hold on to it to long and hurt the turbine.

We tested the igniter under a hard blower but not under heavy thrust. We designed it for a easy start ignition on the J-34.

I will take more pics and post shortly.

Need any help let us know.

ernie

[racket]

Hi Anders Ernie

A guy here in Oz is playing around with a Viper and I did some "numbers" for his engine .............

Heres some theoreticals .................4.31 PR at say 80% effic will give you a temp rise of ~187 deg C so a T2 of ~202 deg C on a standard day .

With a 5% pressure loss across the flametube you'll have a 4.095 PR going into say an 80% effic turb needing to produce a temp drop of ~163 deg C from say a TIT of 950 deg C -1223 K , this will require a pressure ratio of ~2.07:1 across the turb with a TOT of 787 C -1060 K and a PR of 1.98 in the jetpipe ...........enough to go supersonic :-)

The 1.98 PR at 1060K will produce a "theoretical" temp drop of ~156 deg C and a velocity of ~1975'/sec for ~2700 lbs of thrust dry or ~3800 lbs with A/B

Now assuming we only have ~400 ft/sec velocity at the flameholder , 400 ft/sec is worth ~1.5 psi of the total pressure in the jetpipe , your 1.98 PR is ~29.1 psia , minus 1.5 psi dynamic gives us ~27.6 psi static at 1223 K for a density of ~25.6 cu ft/lb or ~1126 cu ft/sec , so we need a duct with ~2.8sq ft add on 10% for flameholder blockage gives a required area of ~3.1 sq ft or a 2 foot - 24 inch diameter duct .

Some Viper turb blades appear to be only ~12% of the overall turb wheel diameter , this is quite a small ratio , hence an A/B duct doesn't need to be a lot bigger than the turbine wheel , an oversized A/B duct only increases skin friction and increases losses , reducing thrust ..............we only need to reduce gas velocity to 400 ft/sec at the flameholder , higher than this and there'll be difficulties .

Now for some fuel data ..............

Assuming a T2 of ~200 C and a T3 of ~900 C thats a 700 deg C rise needing a F/A ratio of ~0.018 ( A/F of ~55 :1 ) or ~47 lbs of kero /min to the flametube or ~27 litres/min

With A/B included and running an overall 15:1 A/F thats ~32.93 lbs/sec 176 lbs/min minus the 47 to the FT that leaves ~129 lbs ( ~20 US GPM ) to the A/B or ~73 LPM of kero ..............yep, pretty close to your 80 LPM assuming only 90% fuel burn effic .

Jet nozzles etc ..........

originally the engine would have had an exhaust gas density ~41 cu ft /lb X 44 = ~1800 CFS div by ~2,000 ft/sec or an area of ~0.9 sq ft or a jet nozzle of ~1.1 ft say 13 inches ,...............now gas density roughly halves in an A/B nozzle so lets double our 0.9 sq ft to 1.8 sq ft , but gas velocity goes up by ~40% so we reduce our 1.8 by 40% for an area of ~1.29 sq ft or ~1.28 ft dia or 15.3 inches , add on a bit for boundary layer and lets go for ~15.5 inch dia "cold" , it will be larger when running .

Cheers
John