Most fuel efficient engine

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astroadrian99
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Most fuel efficient engine

Post by astroadrian99 » Sat May 10, 2014 5:05 pm

Hey guys. I have been thinking of making a pulse engine and I wanted to do sonething big. I am trying to look for plans on the most fuel efficient design that can push 100 lb. I have read in some places that the chinese design is the most efficient but I've read in other places that it is the U-shaped one. So my question is, whats the most fuel efficient design for a pulse engine and are there plans for that design that would allow the engine to give 100 pounds of thrust? If there isn't a plan for a 100 pound one, how can I increase its thrust?
Thanks for the help.

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Re: Most fuel efficient engine

Post by astroadrian99 » Sun May 11, 2014 7:36 pm

Hello? Anybody there?

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Re: Most fuel efficient engine

Post by sid_raptor » Sun May 11, 2014 9:30 pm

Hi! I am new here and from what i can see, replies seem to be slow, but they do come so hang in there....

as far as i can tell, the chinese designs are more fuel efficient. Cant say much about a 100 lbs engine but ive come across a few that can generate 506 lbs...perhaps you can use 2 engines? What exactly do you want to use the 100 lbs engine for? The more details you give, the better answers you will get!
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Re: Most fuel efficient engine

Post by sid_raptor » Sun May 11, 2014 9:31 pm

I made a stupid typo!! I meant 50 not 506....
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Re: Most fuel efficient engine

Post by sid_raptor » Sun May 11, 2014 9:34 pm

oh and take a look here. They are talking about smaller engines than what you are looking for but i think it will answer your questions about efficiency...

viewtopic.php?f=3&t=6312&p=74376&hilit= ... ine#p74376
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Re: Most fuel efficient engine

Post by astroadrian99 » Sun May 11, 2014 10:21 pm

sid_raptor wrote:oh and take a look here. They are talking about smaller engines than what you are looking for but i think it will answer your questions about efficiency...

viewtopic.php?f=3&t=6312&p=74376&hilit= ... ine#p74376
Ok thanks man. Ill check it out.
Honestly, i still dont know what im building it for but I wanted it to 100lb of thrust so it could have many uses. Ive benn thinking of using it for mu bike, a small plane in planing on getting, etc.

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Re: Most fuel efficient engine

Post by sid_raptor » Sun May 11, 2014 10:25 pm

i think a 50lbs engine is more than enough to run a go kart...so i see no reason why it cant run a bike! But remember....these things get very hot and make an unbelievable amount of noise and no video can do that noise justice! be careful and good luck!!!!

Oh and we would love to see vids if you do make one!
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Re: Most fuel efficient engine

Post by sid_raptor » Sun May 11, 2014 10:26 pm

Also i think its easier to start small....just to learn the ropes!
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Re: Most fuel efficient engine

Post by astroadrian99 » Sun May 11, 2014 10:31 pm

sid_raptor wrote:Also i think its easier to start small....just to learn the ropes!
Ok, I'll start small with some 12lb thrust i found yesterday. Just one thing, do you happen to have the link for the 50 pound engines?

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Re: Most fuel efficient engine

Post by sid_raptor » Sun May 11, 2014 10:48 pm

Check the looking for plans section. Im sure you will find what you need there.

Alternatively search for thunderchine or lockwood or m40...

Which 12 lb engine are you going to build? I am starting with Larry's original short lady just because it looked easy to build. I have a thread running documenting the trials and tribulations of my build! (I am a noob too).
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Re: Most fuel efficient engine

Post by astroadrian99 » Sun May 11, 2014 11:09 pm

sid_raptor wrote:Check the looking for plans section. Im sure you will find what you need there.

Alternatively search for thunderchine or lockwood or m40...

Which 12 lb engine are you going to build? I am starting with Larry's original short lady just because it looked easy to build. I have a thread running documenting the trials and tribulations of my build! (I am a noob too).
I'm going to try to build this one, download/file.php?id=14565 cause it seems simple enough to build.

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Re: Most fuel efficient engine

Post by astroadrian99 » Sun May 11, 2014 11:12 pm

sid_raptor wrote:Check the looking for plans section. Im sure you will find what you need there.

Alternatively search for thunderchine or lockwood or m40...

Which 12 lb engine are you going to build? I am starting with Larry's original short lady just because it looked easy to build. I have a thread running documenting the trials and tribulations of my build! (I am a noob too).
I'm going to try to build this one download/file.php?id=14565 cause it seems simple enough to do.

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Re: Most fuel efficient engine

Post by tufty » Mon May 12, 2014 3:04 pm

When talking pulsejets, "fuel efficiency" should always be in "ironic" quotes.

As far as fuel efficiency on big engines goes, SNECMA's "Ecrivisse" was ~100lb thrust with a (heavily tested / proven) TSFC of 1.8 or so. I'm fairly certain there's some engineering drawings for the Ecrivisse lying about somewhere.

They look a bit like this:

Image

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Re: Most fuel efficient engine

Post by astroadrian99 » Mon May 12, 2014 3:34 pm

tufty wrote:When talking pulsejets, "fuel efficiency" should always be in "ironic" quotes.

As far as fuel efficiency on big engines goes, SNECMA's "Ecrivisse" was ~100lb thrust with a (heavily tested / proven) TSFC of 1.8 or so. I'm fairly certain there's some engineering drawings for the Ecrivisse lying about somewhere.

They look a bit like this:

Image
So wait, are they more fuel efficient than the Chinese design?

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Re: Most fuel efficient engine

Post by tufty » Mon May 12, 2014 6:23 pm

astroadrian99 wrote:So wait, are they more fuel efficient than the Chinese design?
Well, the models made, tuned, tested and run by SNECMA got a TSFC of ~1.8. That's pretty damn good, and it's for an engine designed to put out the sort of thrust you want. The "Chinese" design will get you TSFC around 2, and you'll have to scale it up to get 100lb, IMO you'd be lucky to get tsfc < 5 for a "rule of thumb" scaling.

Remember - 100lb at tsfc 2 == 200 lbs of fuel per hour. Or, if you prefer, somewhere between 3 and 6 minutes runtime on a 20lb tank of propane, depending on when it starts icing up. Probably closer to 3 than 6.

It occurs to me that Eric had one of his TP-180 series with tuned augmentor where he was claiming TSFC <1 for 100lb thrust. Not only is that way better than anything out there, but I'm pretty sure you can trust Eric.

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