Calculating top speed on ice...

[Irvine.J]

Thanks M, glad to be back.
Ever so happy we see eye to eye on it. Vapourising coils really do the job well. I can only hope he doesn't go for E85, if its an environmental thing, not much crap will come out of the back of it anyway. Its worth noting too that E85's "Combustion Enhancers" are a potent mix of Toluene, Xylene, benzines, and other horrendous stuff... goes great in a prawn cocktail though. Mung on.
Sliding back under my rock for a little while now... till I pop out again for another lizard dinner

[milisavljevic]

Hmmm...

...till I pop out again for another lizard dinner.

Just what are you implying there?

On second thought, don't answer.

Peace,
M.

[Irvine.J]

Ahh nick and I were working away in the shop and this monster spider ran out of no where and nailed a gecko for dinner.
So right now everything is all about munging onto lizards, just the slang of the day. The "Crawling under a rock thing" was just living under a rock (Like a trapdoor spider) and only coming out for food.
Did I ever show you the pic of the spider eating the bird, I sent it to Viv and said "When you coming to visit".
His answer was "Not until you evolve"
ROFL!

Worth mentioning read the shit above this shenanigans Johansen. I'm getting side tracked

[PyroJoe]

"7: Since the engine was designed for generic hydrocarbon use and not for a specific fuel, you will need to increase your naptha /white spirit (Coleman camp stove fuel) % until such time as you balance the flash speed to the frequency of the engine. I would increase in 5% increments until you find the best mix for your engine."

Nothing to add, just that 7: was spot on.

Joe

[Irvine.J]

Thanks pyro, M's engine is cracker, a valuable engine for the forum. As its design intent was for hydrocarbon fuels it shouldn't be too hard to dial in.
Flash speeds will vary a little due to environmental factors but once nailed down Johanssen's numbers can be fined tuned for other users on a vapour coil setup quite easily for the thunderchine. All engines will run on most liquids, but getting them to their potential on liquids requires that little bit more patience and attention to detail.

[Johansson]

Nice starter you´ve made GRIM, I think we will more or less copy that design if it´s ok with you. It will have to wait until the vehicles are finished though so we know how much space there is around the engines.

Great input on the fuel James, in overcharged piston engines I find E85 a wonderful fuel since it absorbs plenty of heat from the cylinder walls and head when it vapourises and its higher octane number permits higher compression (or boost) thus more power. It smells nice too.

I didn´t give this enough thought when I suggested it as the fuel of choice in the Thunderchine, as you´ve pointed out there are several things talking against E85 so without further discussion I hereby decide that I´ll run it on gasoline instead.

About the spray nozzle placement, my idea is to make a nozzle housing that slides on the intake and have a milled slot in the intake wall around the 25% point so the best placement can be found. Once the spray nozzle is placed at the correct distance from the intake flare the slot can be welded shut and a small hole drilled instead. The "unused" parts of the slot will of course be blocked off by the nozzle plate so no air will get through there.

It is worth a try anyway, we have 10 months to experiment with the engine before the race so there is plenty of time for mistakes and bad ideas...

Here are a couple of pics on the starting fences along with a few more pics showing progress and madness.

[Johansson]

By the way M, I wire brushed the CC and transition cone instead of bead blasted. I remembered that I had already tacked the transition cone and the tail pipe cones together so they wouldn´t fit inside the bead blasting machine...

[milisavljevic]

Hejsan Anders!

I hereby decide that I'll run it on gasoline instead.

Thank you. I tried to be subtle with my objections to E85...but suddenly a big 'ol spider ate my gecko. Bugga!

About the spray nozzle placement, my idea is to make a nozzle housing that slides on the intake and
have a milled slot in the intake wall around the 25% point so the best placement can be found...

We have 10 months to experiment with the engine before the race...plenty of time for mistakes and bad ideas.

Agreed! Please experiment with the off-axis injectors. You may even try a full-thrust run on E85, just to see?

I am looking at transition-mounted injectors for Thunderchine and Thunderhumper; I will let you know if this
shows enough promise to test in your application. Of course, I just let that cat out of the bag, so who knows?

Here are a couple of pics ... showing progress and madness.

Woot!

In the last photo, you are getting close to the intended use of Thunderhumper, a quad of them, to be exact!

Cheers,
M.

[Johansson]

The transition mounted nozzles sounds interesting, worth a try don´t you think? I have the special thread tap for Danfoss spray nozzles so I can make a couple of threaded holders pretty easy for testing alternative fuel injection locations.

[milisavljevic]

Hello Anders,

The transition mounted nozzles sounds interesting, worth a try don't you think?

This is not quite so easy as the Nike folks say it is: "just do it!"

Thunderchine's size is what makes this worth considering (combustor-transition volume: 5.7 liters).
If this does work, it may yet require separate starting injectors positioned in the intakes (eg., two
rosscojectors or similar feeding propane vapour to warm up and start, then switching to liquid fuel
through the transition-mounted Danfoss nozzles* driven by a vapourising coil). Positioning the two
or three nozzles is critical: it requires some modeling, for which I have only just started preparing.

Well... You DO have a little time to experiment. Still interested?

In the meantime, please proceed with your plan for off-axis injectors. It is so good to have options.
You may want to punch out extra intakes and be willing to do "elective surgery" to see this through.

Cheers,
M.

*An alternative to your Danfoss nozzles are modulating sonic injectors (I can provide the plans for).

[Johansson]

We´ve just finished the first engine and Erik (weldion) has cut out most of the parts for the second one, some ideas regarding the thrust stand has been bounced around so we will soon have an engine ready for some serious testing.

With a 90 degree spray pattern and the nozzle tilted 45 degrees it would look like the drawing below, would this be a good starting point for further experimentation if it is movable up and down the intake length?

[weldion]

Now I have started to cut out the parts for the second engine. It's just the parts for the intakes left until I'm done with the cutting.

[milisavljevic]

Hejsan Anders and Erik!

Before you go cutting up too much metal, please take the time to carefully audit Thunderchine #1.

What we need to know are the "as-built" dimensions, which includes all the small errors that have
accumulated between cutting the steel and then welding it back together. Everyone makes errors,
(even Swedes), and it will pay in the long run as my model then reflects the real engines you build.

An audit means measure and record the length and internal diameter for each and every segment.
For all inaccessible internal diameters, use the outside diameter and subtract the metal thickness.

You two are doing superb work, but a quick reality check is not too much to ask early in the game.

Thanks!
M.

[Johansson]

I´ll measure the engine tomorrow, due to the lack of real rollers the cones are not perfectly round but as close as I could make them on the GRIM-roller.

After some calculating I found out that two 10GPH nozzles should provide enough fuel to get the engine to the point of rich extinction (or what it is called) but I guess that that point depends heavily on the location and design of the fuel injection.

Is the design thrust of 55lbs reachable with "simple" propane stingers or does it require a more sophisticated fuel injection? If so, could an optimal fuel system make the engine produce even more thrust or is 55lbs the peak thrust for this engine? The reason why I ask is so I know how to interpret the thrust readings we will get once we start testing the engine, if we reach 45lbs before rich extincion, what does that tell us about the fuel injection and so on...

[milisavljevic]

Hello Anders!

With a 90 degree spray pattern and the nozzle tilted 45 degrees ... would this be a good
starting point for ... experimentation if it is movable up and down the intake length?

Yes, but. A 90 degree pattern is almost certainly going to wet the inside of the intake duct.

Are you still planning to use a high-pressure pump feed, or push the fuel with a vapourising
coil? A coil will not necessarily require the Danfoss atomising nozzles; sonic injector nozzles
similar to those used in pressure jets may be fit for purpose...if not, there are alternatives.

Experimentation required.

Cheers,
M.