## Calculating top speed on ice...

Moderator: Mike Everman

Johansson
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### Re: Calculating top speed on ice...

milisavljevic wrote:what restrains the engine from chattering on top of its cradle?
Nothing at the moment, one of the things we will find out during the propane run is whether the engine will push itself down into the cradle or lift from it once producing thrust.

There are as I can see it two ways to solve this; move the engine thrust mount up a couple of centimeters or weld a bolt to the engine that slides in a milled slot in the bottom of the cradle. I figured that the best way to find out was to do a test run first before modifying the engine in any way.
milisavljevic wrote:Btw., I will have the requested email (with the good stuff!) out to you within 12 hours of this post.
Great!

milisavljevic
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### Re: Calculating top speed on ice...

Hej!
Johansson wrote: I figured that the best way to find out was to do a test run first before modifying the engine in any way.
Oh my. A man with tools, the hands to use them...and a brain that thinks. A rare and most dangerous combination!

Cheers,
M.

PS: Writing up your email now.
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.

Johansson
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### Re: Calculating top speed on ice...

Today I´ve finished the engine mounts, fitted a pair of injector mounts to the intakes and made two simple propane injectors for initial testing this weekend. Things are coming together nicely.

milisavljevic
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### Re: Calculating top speed on ice...

Hejsan Anders!
Johansson wrote:Things are coming together nicely.
I'll say!

What size are your injector ports, and how many do you have per injector? Assuming these are simple orifice
ports, you will need the equivalent of ~ 10 mm2 per injector to realise anything approaching maximum thrust.

Cheers,
M.

PS: I sent out your email hours and hours ago. Please let me know if it has failed to arrive.
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.

Johansson
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### Re: Calculating top speed on ice...

The internal diameter of the copper tubes is ~5mm, so the total injector area is 40mm2. I have not capped the tubes and drilled any holes or so, just plain tubes with a hole in the end.

The email has arrived and a reply is well on its way through the Atlantic fibre optical cable.

milisavljevic
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### Re: Calculating top speed on ice...

Hej!
Johansson wrote:The total injector area is 40mm2.
You will likely need to cut this down by half or so. After testing the open probe tips "as is",
you may want to snip and crimp both tips down, Rosscojector style. Whatever works best.
Johansson wrote:The email has arrived and a reply is well on its way through the Atlantic fibre optical cable.
Found it, read it, replied to it.

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.

Johansson
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### Re: Calculating top speed on ice...

milisavljevic wrote:you may want to snip and crimp both tips down, Rosscojector style.
I hear you, brother!

Johansson
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### Re: Calculating top speed on ice...

Sometimes it becomes quite obvious that I really like manifacturing, this evening for example when I spent over one hour with the lathe and TIG making a T-connection for the propane hose. If I had waited until tomorrow I could have bought one for a couple of bucks.

Anyway, the kick is finally ready for its first test this weekend.

milisavljevic
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### Re: Calculating top speed on ice...

Hejsan Anders!
Johansson wrote:Sometimes it becomes quite obvious that I really like manufacturing.
Never would have noticed that about you, mate.
Johansson wrote:The kick is finally ready for its first test this weekend.
Woot!

Be prepared to be patient: Thunderchine can be rather difficult to start. Tim ("wakmat") was able
to start his Thunderlite on the spot after we sorted out the fuel delivery. So, it can be done, mate!

With two 5 mm open-end probes, I suspect you may need to stock up on patience the night before...

Don't say I didn't warn you.

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.

Jutte
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### Re: Calculating top speed on ice...

Wow - looks good - woowee dude I 'll be
seriously reconsidering how you're gonna stop that beast -
it looks like it might get you there really really quickly...LOL!!!
Last edited by Jutte on Wed Jul 08, 2009 12:55 am, edited 1 time in total.

GRIM
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### Re: Calculating top speed on ice...

Hi Johannson ,

Awesome build , Excellent workmanship ,

Re, Injectors , I have not tried Rosscoes on my Thunderchine ( I wish I had ), You might consider crimping your copper tube down Rosscoe style, BUT crimp down on feeler gauges with smooth jaw pliers , I have found that this at least gives a calibrated orifice , and it is easier to ensure that multiple injectors are at least similar in their potential flow rates , you do however have to mutilate a set of feelers ,

Cutting the tube off with side cutters and then pinching them open a little produces a weird shaped hole ,

Just 2 cents , and good luck for the weekend ,

Johansson
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### Re: Calculating top speed on ice...

milisavljevic wrote:Be prepared to be patient: Thunderchine can be rather difficult to start. Tim ("wakmat") was able
to start his Thunderlite on the spot after we sorted out the fuel delivery. So, it can be done, mate!

With two 5 mm open-end probes, I suspect you may need to stock up on patience the night before...
Point taken, I will make a dual outlet nozzle for the leaf blower and bring a bag of tools in case I need to modify the injectors or anything else. The first test will have to be with a single propane bottle since I only have one in that size, later I will try to borrow a second one and do another test.
Jutte wrote:Wow - looks good - woowee dude I 'll be
seriously reconsidering how you're gonna stop that beast -
it looks like it might get you there really really quickly...LOL!!!
Thanks! About the braking, how about bolting down a hockey goal at the end of the track?
GRIM wrote:Hi Johannson ,

Awesome build , Excellent workmanship ,

Re, Injectors , I have not tried Rosscoes on my Thunderchine ( I wish I had ), You might consider crimping your copper tube down Rosscoe style, BUT crimp down on feeler gauges with smooth jaw pliers , I have found that this at least gives a calibrated orifice , and it is easier to ensure that multiple injectors are at least similar in their potential flow rates , you do however have to mutilate a set of feelers ,

Cutting the tube off with side cutters and then pinching them open a little produces a weird shaped hole ,

Just 2 cents , and good luck for the weekend ,
Thanks a lot! I could make a substitute for the feeler gauge from 1mm sheet metal which should give each injector an opening of 5-6mm2. I guess that the engine won´t turn self-starting after that but if it improves starting even a bit it would be worth the effort.

milisavljevic
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### Re: Calculating top speed on ice...

Hejsan Anders!
Johansson wrote:I will make a dual outlet nozzle for the leaf blower.
Bad idea, that; starting air need only be applied to one inlet. Joe has had some experience with this.
Johansson wrote: bring a bag of tools in case I need to modify the injectors or anything else.

Good idea, that. And not just for Swedes.

Johansson wrote:I guess that the engine won't turn self-starting after that.

Not sure what you mean (or expect). The modulating injectors I provided *may* deliver self-starting
performance, yet Joe had no joy for his trouble. Chinese types are not easy to satisfy in this regard.

I mean Chinese type pulsejets, not just girlfriends. Oh, snap!

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.

Johansson
Posts: 1161
Joined: Sun Nov 21, 2004 9:42 pm
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Location: Northern Sweden

### Re: Calculating top speed on ice...

milisavljevic wrote:Bad idea, that; starting air need only be applied to one inlet. Joe has had some experience with this.
Ok, that saved me some work.
milisavljevic wrote:Not sure what you mean (or expect). The modulating injectors I provided *may* deliver self-starting
performance, yet Joe had no joy for his trouble. Chinese types are not easy to satisfy in this regard.
Some engines seems to be self starting with a Rosscojector, but my guess was that this won´t be the case for this engine with the copper tube injectors.

GRIM
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### Re: Calculating top speed on ice...

Hey Anders ,
Being as you are planning to only use one propane cylinder, you might try blocking one inlet , I tried this , didnt seem to be any better , subsequently lost the lollpop in the sand and never tried again ,

very quick and easy to make , just slides over the flare , might be worth a shot , and with your setup you could even dispense with the smalll slot and run just one injector ,

For what its worth , do try to obtain another gas cylinder,and run them in paralell, I think you will struggle with only one ,
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