Calculating top speed on ice...

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milisavljevic
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Re: Congratulations!

Post by milisavljevic » Sun Jul 12, 2009 12:02 pm

Hejsan Anders!
Johansson wrote: As you can see we had a very successful first test.
Awesome video, mate! Despite the compression imposed by Youtube, the acoustic spectrum is excellent.

Motor resonance frequency (via f1-f6 series weighted average) is 163.3-163.5 Hz (excellent agreement);
with peak acoustic power at f3 (spot on), followed by f4, f2, f5, f6 and f1 (yes, fundamental is weakest).

Music to mine ears! :P
Johansson wrote: After a couple of attempts I crimped the injectors down to a 1x7mm slot.
Don't say we didn't warn you. LOL.
Johansson wrote: I consider this engine as a test engine and will most likely build a stainless one once this one runs as it should.
And this one looks so good with its sexy black coating. Btw., what is that? Has a greasy sheen... WD-40?
Johansson wrote: Another good thing is that the tail won't lift from the rear cradle mount.
Good to know. This will remain true after you add the ejectors; the ejectors are canted slightly upwards.
Johansson wrote:Nice echo. (from video)
Most impressive. Even the trees looked to be shaking. That's more air than most politicians can muster!

I will sleep a very happy sleep today! Congratulations, mate! :P

Cheers,
M.
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Re: Calculating top speed on ice...

Post by Johansson » Sun Jul 12, 2009 12:08 pm

Hi M!

Sounds good that the engine behaves as predicted, the nice black colour is from coating the engine with WD-40 before and after running. Looks really nice, too bad with the flaking though.

Here is another run of the engine along with a captured pic of the heat pattern on the engine. Any thoughts about this?

http://www.youtube.com/watch?v=cKO3INCoaTQ
heat pattern.jpg

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Ice hot!

Post by milisavljevic » Sun Jul 12, 2009 12:20 pm

Hej!
Johansson wrote:Any thoughts about this? [ heat pattern ]
Looking now. Was the photo taken with the injectors frosted, or after they thawed out?

Cheers,
M.

Additional:

Back now. Due to the camera (microphone) location (ca. 90 deg. relative to motor axis),
resonance frequency has up-shifted to ca. 167 Hz and peak power is radiated at f2 (this
is also from the low power level). Results remain in excellent agreement with the model.
Last edited by milisavljevic on Sun Jul 12, 2009 12:44 pm, edited 1 time in total.
no safe haven for merchant scum


for ye merchants who do the prop'r t'ing only if
ye be haul'd-up on charges b'fore ye ship-mates
an' threat'nd wit' forfeiture of all ye precious loot
hear this - so-called stand-up guys YE BE NOT

avast!
Cap'n M.

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Re: Calculating top speed on ice...

Post by Johansson » Sun Jul 12, 2009 12:32 pm

The injectors were quite frosty since the engine hadn´t run for long. If we had more propane with us we could have done some longer tests to find out how the heat pattern looked after, say, 2 minutes of running.

It will be interesting to see how the engine behaves on E85, we discussed the starting procedure and figured that a single removeable propane stinger can be fitted in the intake that the leaf blower blows into and the engine can then be started and heated up with this stinger until the vapour coil is hot enough to boil the liquid fuel. Heating the coil manually would probably be difficult since it wouldn´t be possible to heat the entire coil with a torch.

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Re: Ice hot!

Post by milisavljevic » Sun Jul 12, 2009 1:05 pm

.
Johansson wrote:The injectors were quite frosty since the engine hadn't run for long.
Understood. I think the captured heat pattern is acceptable, even if it is shifted deep into the tailpipe,
as longer firings will see this reversed. The acoustics are excellent, and these carry much more weight
with me than external visual indicators. "Acoustics will always tell you if the pulsejet is Sound." LOL. :P

(bad pun)

I really want to see (and hear) this baby running at full grease and in a darker environment (night run!). :twisted:

Cheers,
M.
no safe haven for merchant scum


for ye merchants who do the prop'r t'ing only if
ye be haul'd-up on charges b'fore ye ship-mates
an' threat'nd wit' forfeiture of all ye precious loot
hear this - so-called stand-up guys YE BE NOT

avast!
Cap'n M.

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Re: Calculating top speed on ice...

Post by GRIM » Sun Jul 12, 2009 3:40 pm

CONGRATULATIONS GENTLEMEN , :D
Great vids and photos , Cant wait to see how she performs on liquid ,

Below is some details of the gas/liquid setup that I used for my last couple of runs , this does work and allows "transition" from gas to liquid , via the same coil /injector setup , Hope it is of some use , either way keep up the great work , and thanks for sharing your adventures
Attachments
IMG_0391 (Small).jpg
TRANS.JPG

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Re: Calculating top speed on ice...

Post by Mike Everman » Sun Jul 12, 2009 3:44 pm

Congratulations! Love how the tools are hopping around on the trailer, and the trees dancing oh so far away! Far out, love it! ha ha
Mike
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Re: Calculating top speed on ice...

Post by Johansson » Sun Jul 12, 2009 4:39 pm

Thanks a lot guys!

GRIM, that setup looks interesting for sure. Have you been able to run it flat out on liquid only? Video? 8)

I guess that I will copy your fuel setup, much better than the propane stinger I suggested earlier. Have you any idea if your vapour coil is of the right size of if it should be shorter/longer? The one I´ve made is only two turns around the CC so it is aprox. half the length of yours, perhaps it needs to be a bit longer.

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Re: Calculating top speed on ice...

Post by GRIM » Sun Jul 12, 2009 5:28 pm

Hi Johannson ,
No unfortunately I havent been able to run it on liquid only , BUT this was simply due to having only a small 1 LITRE fuel container , and testing alone, ( I need a Låmbas ) as you know its tough to coordinate the air , fuel and ingnition etc , and every time I was getting to the transition point I ran out of fuel :roll: , however I was soo close a couple of times that I can confidently say that it will work ok ,

Next time I will use an electric pump and a much larger fuel container, (and hopefully a helper)

I used 3/8" od tube for my coil, mainly because I had some 3/8 jic fittings on hand , I dont think it is "necesary" to go so big , I just used all the length of tube that I had so as not to have a short piece laying around collecting dust , jUST THE SAME I dont think you can have "too much" coil ,

Wrt the flow control , this is a pneumatic device, readily available from anyone who sells pneumatic cylinders and such like ,

http://www.smc.eu/portal/WebContent/cor ... oducts.jsp

You probably have something suitable from your turbines ,

I can also see some potential for a QD (quick disconnect ) fitting on the gas, something like used on compressors with self seal stoppers on both sides to allow easy removal of the gas once running on liquid , and prior to letting her Rip, :D

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Re: Calculating top speed on ice...

Post by Johansson » Sun Jul 12, 2009 7:30 pm

A helper is much needed for these sorts of tests, especially one that invites you for coffee and cakes after the test. 8)

I´ll try to get it running on liquid with this coil first, if the fuel comes out only partly vapourized I´ll fit a couple of turns more to it. As for throttling, I made a throttle valve for the pocketbike project a couple of years ago which might come in handy now.
Gasreglage 7.JPG
Gasreglage 13.JPG
Gasreglage 14.JPG

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Re: Calculating top speed on ice...

Post by tufty » Sun Jul 12, 2009 8:13 pm

Very pretty...

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Throttle unbound

Post by milisavljevic » Mon Jul 13, 2009 12:43 am

Hejsan Anders!
Johansson wrote: A helper is much needed for these sorts of tests, especially one that invites you for coffee and cakes after the test.
<comeback="AustinPowers"> Oh, behave! </comeback> :wink:
Johansson wrote: I made a throttle valve for the pocketbike project a couple of years ago which might come in handy now.
Wow. :o

Got a schematic of that? ( And by "that", I mean "all of that". And by "got", I mean "got, and that you can share". :D )

Cheers,
M.
no safe haven for merchant scum


for ye merchants who do the prop'r t'ing only if
ye be haul'd-up on charges b'fore ye ship-mates
an' threat'nd wit' forfeiture of all ye precious loot
hear this - so-called stand-up guys YE BE NOT

avast!
Cap'n M.

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Re: Calculating top speed on ice...

Post by Johansson » Mon Jul 13, 2009 8:18 pm

It must be your lucky day, I just drew a schematic of the throttle valve in Paint. What a coincidence! :mrgreen:
Throttle cutthrough.JPG
I made some progress on the mounts for the fuel cell, pump and throttle valve today. I ran out of steel plates before I could make the battery mount so I will have to "borrow" some from my father when I visit him on my vacation, so it will have to wait a couple of weeks until I get back.
Sparken 090.jpg
Sparken 091.jpg
Sparken 092.jpg
Sparken 094.jpg
Sparken 096.jpg

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Re: Throttle unbound

Post by milisavljevic » Tue Jul 14, 2009 2:00 am

Hejsan Anders!
Johansson wrote:It must be your lucky day!
Thanks, mate!

Looking better everyday. While you wait for more steel, do you have other mischief planned? :twisted:

Cheers,
M.

PS: By "mischief", I mean "Night run, please!" (dawn or twilight will do). Maybe 60 seconds. :twisted:
no safe haven for merchant scum


for ye merchants who do the prop'r t'ing only if
ye be haul'd-up on charges b'fore ye ship-mates
an' threat'nd wit' forfeiture of all ye precious loot
hear this - so-called stand-up guys YE BE NOT

avast!
Cap'n M.

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Re: Calculating top speed on ice...

Post by Johansson » Tue Jul 14, 2009 5:11 am

No time for any night runs for a couple of weeks, on thursday I go on a 3 week vacation and most of that time will be spent on my motorcycle so the kick will have to wait for a while.

About the throttle valve, the needle is ground so the fuel flow is roughly linear, I measured it with a 2GPH spray nozzle at the end to get some back pressure.
Fuel pressure graph 2.JPG

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