www.pulse-jets.com

Posted: **Sat May 19, 2007 2:17 am**

well the gokart is finished, i have pics but i dont have the right format to put them on here. well i test drove it today, i was really impressed as i never seen in real life what a pulse jet can power, it accelerated me about 5 times faster than i was expecting it to which was pretty good acceleration, i think i was allready rolling 20 mph in about 7 sec and after 20 mph it seems like it would pick up speed alot faster as it just kept on pushing, i didnt get faster than a little over 20 mph because the engine was burning the hell out of my back and i almost lost controll of the kart because i was trying to lean forward away from the u bend pipe and holding the propane tank at the same time, the kart was also able to accelerate me up the road going uphill quite well, way way more than i thought it would, i think this go kart can probably go about 85- whatever mph, but it seems like this kart gets strolling really fast, kinda like zacks pulse jet kart that is somewhere on the internet but i think his engine is way bigger, well anyway does any body have any ideas on a good heat shield and should the heat shield be closer to the engine or closer to me? also i had the propane fixed to the kart, but when it was like that it was sitting upside down so liquid can flow out but even with the low flow valve i had on it, even if i just cracked it open barely i couldnt get the engine to start so i had to take the propane out of the holder built into the frame and tip the tank right side up so it was feeding vapor, and thats the only way i could start it, and i had to carry it on my lap while driving and tip it sideways and the upside down on my lap to throttle it which is also why i didnt want to go fast because one of the times i almost dropped the tank and almost had it dragging on the concrete. does any body know if it can be started with the tank upside down so that way i can have it mounted in the frame with out haveing to hold it and throttle it that way. ill post pics soon and some video. hey eric can you post those pics on here i sent to you on your email?

Posted: **Sat May 19, 2007 5:36 am**

Hey, downloading the pics and video as I type this. The injector is set up so that the liquid propane will travel through the narrow fuel tube, then expand into the larger fuel tube and turn to vapor, im not sure if you will be able to do your normal torch behind the intake start but with a spark plug it will work no problem.

Aluminum flashing will work very well to reflect the heat, but you dont want it flimsy and flapping around.

Wow... that looks wild.

Is there any way you can lower the engine mount and stretch the frame in the back so that the engine and the center of gravity is lower? I would also set it up so the engine is pointing so that it will want to push the cart down on the road, and not bounce around going from pushign down to lifting up, which would be very bad for controlling it.

I'll get those videos converted tomorrow for you.

Eric

Posted: **Sat May 19, 2007 2:05 pm**

hey eric, thanks alot, preciate it! well yea i thought about lowering the engine and i might do so here in a little bit, i just need to work on the heat sheild and starting with the propane tank upside down, hey if the heat shield is more reflective does that meant it is better? also it seem like when the tank is upside down even with it barely cracked open and i even have a second valve that can let me throttle really low and if i barelly crack that open and the tank is upside down it wants to throttle the engine up some so i guess i woulndnt have good throttling range. well eric i cant try your method unless i get a new spark plug, because i got carried away with shaving off extra weight and grinded the spark plug all the way down so its pretty much just like a bolt, and yea it probably didnt really make a difference but oh well, well this engine you built me has 'strong push'',i love it!, well hope to get some vidoes and not be harrased by the pigs" as i try to test this out on a country raod somewhere near town.

Posted: **Sat May 19, 2007 2:33 pm**

The pictures aren't there for some reason.

You might want to try a service like Pbase.
Here's one of my albums on Pbase so you can see some pics.

http://www.pbase.com/mark_42/favorites

The basic account is pretty reasonable, and you can link directly.
If you send me the pics, I'll put them in a folder on my Pbase
account so you can see how it behaves and what advantages
there are.

BTW, for a heat reflector, aluminum is not the best metal.
It conducts heat very well, so it will allow heat to transfer.
Steel sheet, or even a tin can (coffee cans work great) will
make a better reflector.

Posted: **Sat May 19, 2007 2:39 pm**

hmm well i cant view the photos either but i thought it was because my goverment computer that im on didnt have the program to let me view them.

Posted: **Sat May 19, 2007 2:41 pm**

hmmm, tin can material or tin can? :?

Posted: **Sat May 19, 2007 2:55 pm**

Tin can material... basically a pair of tin snips and some
soup cans and/or coffee cans make good cheap heat shields.

You can even layer them... a 1/3rd section of soup can
closest to the engine then a 1/3rd section of a 1 lb coffee
can below it, and if needed, another layer from a 2 or 3 lb
coffee can (depending on size of engine, of course).

On a big engine you could flatten them and arrange
them like roofing shingles.

If you email me the pictures I'll put them on my Pbase page
I'll keep them there for at least 6 months unless you ask
me to remove them before then. It'll give you time to figure
out a way to do it. I could also make them smaller and upload
them directly to this message thread if you prefer, that way you
don't have to worry about me deleting them eventually if I need
space (which won't happen soon because my Pbase account is the
huge capacity type)

my email is M_Kanzler (at) yahoo.com

Posted: **Sat May 19, 2007 2:59 pm**

so its best to have the heat shield closer to the engine rather than closer to me?

Posted: **Sat May 19, 2007 5:00 pm**

just sitting here bored and thinking>> my p jet wieghs 25 lbs with every thing i have on it, my gokart weighs about 90 lbs but thats just a guess' and i weigh 200lbs and my propane tank weighs 20lbs to whatever it consumes after that and then being the end weight, well on start off that means every thing added together makes a total weight of 325lbs and my p jet produces anywhere from 70lbs of thrust- 85lbs maybe'' with the advanced injector which i haveon it, i have not tested the acctual thrust my self, but thats what the desighn is rated at, so lets just say it produces 80lbs thrust, that means it has a thrust to weight ratio of 1:4.1 or something like that but my math is bad, but anyway that thrust to weight ratio is pretty good if you compare that to your average passenger airplane right? because i think some aircrafts i looked up on the internet say they were about 1:5 to maybe 1:7 thrust to weight ratio, so that should excellerate faster right :D "in the perfect world".

Posted: **Sat May 19, 2007 9:36 pm**

I wish I could see a pic of your ride. With no photo, I have no Ideas of what happened. I would think the J-Bend is your most concern. If you do like a automobile exhaust and cover it with shield, it my get hot enough to suck in or melt down. With out a photo, I can only think of a couple of Ideas:

Heat is Infra Red Radiation. Some light form of shield will be needed.

Another bug sprayer with water injected to copper tube wrapped around the J-Bend. You could inject the same hot water Aft the C.C. in order to gain exhaust mass and gain some thrust. A small air scoop that would bring ambient air from above or sides over the hot spot and away from you!

The hot water or steam Idea may get you a few lbs of thrust! I planned on trying the water injection on the 20lber. I can silver solder the injector as the flow would keep the joint cool!

What do you think Eric?

Jim

Posted: **Sun May 20, 2007 7:24 am**

Hmmm the pictures show up on the file list but arent there, and one of my posts and the picture attached to it dissapeared entirely. I think there must have been a hickup on the forum, maybe reverted back to a backup?

I'll wait till morning and see if Mike knows whats going on before uploading them again.... dont want to break the site.... OH! on that note I was able to restore my forum and add a few security type things to help prevent bots from signing up, and I deleted all the spam. If this forum is ever out of commission you can check mine out to see if anything is going on. http://www.beck-technologies.com/phpBB2

Adam the cart would accelerate at around 2.4 m/s/s which means that it would do a quarter mile in 18 seconds, @96 mph ( not including drag). It would do a mile in 36 seconds @195 mph.... and at the end of a minute you would be going 325 mph :D A Mclaren F1 goes about 246 mph last time I checked, so in a long race your cart would beat the million dollar car :P

This is all not considering drag, speeds cheif enemy. Jets are relatively slow off the line unless you have a ton of thrust, but just like heavy passenger planes if you have a fairly aerodynamic vehicle, you can get going pretty damn fast.....

without drag/friction in 1 hour you would be going 19,000 mph

Eric

Posted: **Sun May 20, 2007 9:35 am**

Eric wrote:Hmmm the pictures show up on the file list but arent there, and one of my posts and the picture attached to it dissapeared entirely. I think there must have been a hickup on the forum, maybe reverted back to a backup?

Yeah, my money's on a phpBB or MySQL foulup. a couple of my posts are gone, and I came back in to find myself logged out this morning.

Adam the cart would accelerate at around 2.4 m/s/s which means that it would do a quarter mile in 18 seconds, @96 mph ( not including drag). It would do a mile in 36 seconds @195 mph.... and at the end of a minute you would be going 325 mph :D A Mclaren F1 goes about 246 mph last time I checked, so in a long race your cart would beat the million dollar car :P

This is all not considering drag, speeds cheif enemy. Jets are relatively slow off the line unless you have a ton of thrust, but just like heavy passenger planes if you have a fairly aerodynamic vehicle, you can get going pretty damn fast.....

Drag is not just your worst enemy, it's gonna stop you dead. Adapted from my calcs in the other ugly stick fogging thread:

80lbf = 356N. Assume rolling resistance of around 1N, that makes forward thrust of 355N.
Assume frontal area of .5m^2
Assume Cd of around 0.7
Weight is 150Kg or so.

Acceleration at any given point is given by (355 - (0.21 * v^2))/150, plugging that into the following modification of my little program:

Code: Select all

#!/usr/local/bin/ruby
v = 0.0
a = 0.0
d = 0.0
t = 0.0
a = (355 - (0.21 * (v ** 2)))/150
while (a*100).to_i > 0 do
  puts "Time : #{'%0.2f' % t}s, Distance : #{'%0.2f' % d}m, Velocity : #{'%0.2f' % v}m/s, Acceleration #{'%0.2f' % a}m/s^2"
  v += a
  t += 1
  d += v
  a = (355 - (0.21 * (v ** 2)))/150
end

The above code calculates acceleration, cumulative velocity and distance vs time while acceleration is positive.

Results for the figures above:

Code: Select all

Time : 0.00s, Distance : 0.00m, Velocity : 0.00m/s, Acceleration 2.37m/s^2
Time : 1.00s, Distance : 2.37m, Velocity : 2.37m/s, Acceleration 2.36m/s^2
Time : 2.00s, Distance : 7.09m, Velocity : 4.73m/s, Acceleration 2.34m/s^2
Time : 3.00s, Distance : 14.15m, Velocity : 7.06m/s, Acceleration 2.30m/s^2
Time : 4.00s, Distance : 23.51m, Velocity : 9.36m/s, Acceleration 2.24m/s^2
Time : 5.00s, Distance : 35.11m, Velocity : 11.60m/s, Acceleration 2.18m/s^2
Time : 6.00s, Distance : 48.89m, Velocity : 13.78m/s, Acceleration 2.10m/s^2
Time : 7.00s, Distance : 64.77m, Velocity : 15.88m/s, Acceleration 2.01m/s^2
Time : 8.00s, Distance : 82.67m, Velocity : 17.89m/s, Acceleration 1.92m/s^2
Time : 9.00s, Distance : 102.48m, Velocity : 19.81m/s, Acceleration 1.82m/s^2
Time : 10.00s, Distance : 124.11m, Velocity : 21.63m/s, Acceleration 1.71m/s^2
Time : 11.00s, Distance : 147.45m, Velocity : 23.34m/s, Acceleration 1.60m/s^2
Time : 12.00s, Distance : 172.40m, Velocity : 24.95m/s, Acceleration 1.50m/s^2
Time : 13.00s, Distance : 198.84m, Velocity : 26.44m/s, Acceleration 1.39m/s^2
Time : 14.00s, Distance : 226.67m, Velocity : 27.83m/s, Acceleration 1.28m/s^2
Time : 15.00s, Distance : 255.78m, Velocity : 29.11m/s, Acceleration 1.18m/s^2
Time : 16.00s, Distance : 286.07m, Velocity : 30.29m/s, Acceleration 1.08m/s^2
Time : 17.00s, Distance : 317.44m, Velocity : 31.37m/s, Acceleration 0.99m/s^2
Time : 18.00s, Distance : 349.81m, Velocity : 32.36m/s, Acceleration 0.90m/s^2
Time : 19.00s, Distance : 383.07m, Velocity : 33.26m/s, Acceleration 0.82m/s^2
Time : 20.00s, Distance : 417.15m, Velocity : 34.08m/s, Acceleration 0.74m/s^2
Time : 21.00s, Distance : 451.97m, Velocity : 34.82m/s, Acceleration 0.67m/s^2
Time : 22.00s, Distance : 487.46m, Velocity : 35.49m/s, Acceleration 0.60m/s^2
Time : 23.00s, Distance : 523.55m, Velocity : 36.09m/s, Acceleration 0.54m/s^2
Time : 24.00s, Distance : 560.19m, Velocity : 36.64m/s, Acceleration 0.49m/s^2
Time : 25.00s, Distance : 597.31m, Velocity : 37.12m/s, Acceleration 0.44m/s^2
Time : 26.00s, Distance : 634.88m, Velocity : 37.56m/s, Acceleration 0.39m/s^2
Time : 27.00s, Distance : 672.83m, Velocity : 37.95m/s, Acceleration 0.35m/s^2
Time : 28.00s, Distance : 711.13m, Velocity : 38.30m/s, Acceleration 0.31m/s^2
Time : 29.00s, Distance : 749.75m, Velocity : 38.62m/s, Acceleration 0.28m/s^2
Time : 30.00s, Distance : 788.64m, Velocity : 38.89m/s, Acceleration 0.25m/s^2
Time : 31.00s, Distance : 827.78m, Velocity : 39.14m/s, Acceleration 0.22m/s^2
Time : 32.00s, Distance : 867.15m, Velocity : 39.36m/s, Acceleration 0.20m/s^2
Time : 33.00s, Distance : 906.71m, Velocity : 39.56m/s, Acceleration 0.18m/s^2
Time : 34.00s, Distance : 946.45m, Velocity : 39.74m/s, Acceleration 0.16m/s^2
Time : 35.00s, Distance : 986.34m, Velocity : 39.89m/s, Acceleration 0.14m/s^2
Time : 36.00s, Distance : 1026.37m, Velocity : 40.03m/s, Acceleration 0.12m/s^2
Time : 37.00s, Distance : 1066.53m, Velocity : 40.16m/s, Acceleration 0.11m/s^2
Time : 38.00s, Distance : 1106.79m, Velocity : 40.26m/s, Acceleration 0.10m/s^2
Time : 39.00s, Distance : 1147.15m, Velocity : 40.36m/s, Acceleration 0.09m/s^2
Time : 40.00s, Distance : 1187.60m, Velocity : 40.45m/s, Acceleration 0.08m/s^2
Time : 41.00s, Distance : 1228.13m, Velocity : 40.52m/s, Acceleration 0.07m/s^2
Time : 42.00s, Distance : 1268.72m, Velocity : 40.59m/s, Acceleration 0.06m/s^2
Time : 43.00s, Distance : 1309.37m, Velocity : 40.65m/s, Acceleration 0.05m/s^2
Time : 44.00s, Distance : 1350.07m, Velocity : 40.70m/s, Acceleration 0.05m/s^2
Time : 45.00s, Distance : 1390.82m, Velocity : 40.75m/s, Acceleration 0.04m/s^2
Time : 46.00s, Distance : 1431.62m, Velocity : 40.79m/s, Acceleration 0.04m/s^2
Time : 47.00s, Distance : 1472.45m, Velocity : 40.83m/s, Acceleration 0.03m/s^2
Time : 48.00s, Distance : 1513.31m, Velocity : 40.86m/s, Acceleration 0.03m/s^2
Time : 49.00s, Distance : 1554.20m, Velocity : 40.89m/s, Acceleration 0.03m/s^2
Time : 50.00s, Distance : 1595.12m, Velocity : 40.92m/s, Acceleration 0.02m/s^2
Time : 51.00s, Distance : 1636.06m, Velocity : 40.94m/s, Acceleration 0.02m/s^2
Time : 52.00s, Distance : 1677.02m, Velocity : 40.96m/s, Acceleration 0.02m/s^2
Time : 53.00s, Distance : 1718.00m, Velocity : 40.98m/s, Acceleration 0.02m/s^2
Time : 54.00s, Distance : 1758.99m, Velocity : 40.99m/s, Acceleration 0.01m/s^2
Time : 55.00s, Distance : 1800.00m, Velocity : 41.01m/s, Acceleration 0.01m/s^2
Time : 56.00s, Distance : 1841.02m, Velocity : 41.02m/s, Acceleration 0.01m/s^2

It's a relatively rough guesstimation, of course, but that gives "flat out" speed (terminal velocity) of 91mph after about a minute, and 1.1 miles travelled. Standing start quarter mile (400m) time is around 20s, time to 60mph (26.8m/s) around 13s. Never mind beating a formula 1 car, you're gonna have trouble beating a fiat panda :)

This all goes to show why the 2 things that motorcycle manufacturers concetrate on most for race bikes is reducing weight (thus increasing acceleration across the board) and better streamlining (thus pushing the terminal velocity point out further for a given power output).

Simon

Posted: **Sun May 20, 2007 11:42 am**

Mark 42 wrote:The pictures aren't there for some reason.

strange I have seen them but now the are gone.

Posted: **Sun May 20, 2007 1:49 pm**

Very odd. I went to the file list
http://www.pulse-jets.com/filelist.php
And the files show as being there, but when I click an
individual file URL
http://www.pulse-jets.com/phpbb2/files/ ... 1__491.jpg
I get a 404 Error

Eric wrote:...the cart would accelerate at around 2.4 m/s/s

The geek in me has to take you to task... m/s^2 would be correct...
m/s/s works out as just m (the s's cancel each other out).

Also, similar off topic niggle...
Kelvins don't use the degree symbol.
There is no such thing as a farenheidt, a celsius/ or a rankine
but there is such a thing a a kelvin. Kelvin is a unit, the others
are scales so it's °C, °F, K & °R (w/o the degree symbol for
number of kelvins).
http://en.wikipedia.org/wiki/Kelvin

And while I'm on a roll, there is no "H" ath the end of Height.

Okay, I got that off my chest now.
'course, now I opened myself up to having my posts picked
at, but I don't mind too much if it's meant well.

Hopefully I haven't offended anyone.

I'm still hoping to see pictures of the Bat-Kart

Posted: **Sun May 20, 2007 3:54 pm**

thought i might share this with anyone who cares :D , my gokart has some pretty good "jet blast" some cars driving by saw me messing around with my new gokart with the p jet mounted to it and stopped and couldnt help but ask "what the hell is that" so i told them and did a demonstration of the jet that i suppose some of the average people "like some of the folks i work with" wont think will work because it is of course just hollow piping welded together. So anyway, and not to say anything about fat people because i am on the heavey side too but this really really fat guy comes over with this huge curious smile on his face and asks me if he could see it run, so i start it and tell him to cover his ears and walk back into the exhaust of the engine while its on full blast and he gets back behind it about 6 or so feet with it just roaring away and all you see is all his fat rolls on his face just rippiling from his mouth to his ears continueosly like if he was sticking his head out of his car window and going about 80 down the highway. hahaa just thought it was really funny to me.

www.pulse-jets.com

the 70lber batmobile

the 70lber batmobile

hot seat

pictures