augmenter for M40

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ganuganu
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augmenter for M40

Post by ganuganu » Sun May 01, 2011 2:58 pm

hello everyone iam ganesh,i made a M40 engine designed by metiz..now i want to add an augmenter for this engine using pulsejet calculator..

the following was given as input
exhaust dia: 15cm
throat dia: 7cm
exhaust length: ?

i dont what value should be given for exhaust length,whether we should add even the throat length or not..here is the design..
http://img703.imageshack.us/i/overviewnewm40.jpg/

iam going to publish this engine project in the news paper.Thats why i planned of adding an augmenter in the exhaust side...

help please..

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Re: augmenter for M40

Post by ganuganu » Mon May 02, 2011 10:16 am

i just got this link while browsing in pulsejet forum..

viewtopic.php?f=7&t=5694

according to this formula i have calculated the augmenter for this engine designed by metiz..

http://img703.imageshack.us/i/overviewnewm40.jpg/

delta= 2*dj=2*15=30cm

D= 2.6*dj=2.6*15=39cm

L= 10*dj=10*15=150cm

R= 0.25*D=0.25*39=9.75cm

i dont know whether these calculations are correct or not because the augmenter length is about 150cm here,iam confused how an augmenter can be this much big in size..

metiz
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Re: augmenter for M40

Post by metiz » Tue May 03, 2011 9:58 pm

Ok how about this. Just a prototype, don't go out and bolt it together yet. can ANYONE remember their login name and pass and care to give some feedback?
Attachments
m40 augmenter.GIF
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Re: augmenter for M40

Post by Jutte » Wed May 04, 2011 11:12 am

Hi ganuganu,
On most Pulse Jets the Augmentor is placed on the intakes - as the bigger the
Pulse Jet is ,the augmentor starts to get rather large in regards to a tail pipe augmentor.This gets to a point where there it can cause a serious drag problem.If you check out some of the French Snecma ecrevisse type of engines - when fully faired
only the intake was augumented.
However in saying that - yes you can still augment a tail pipe - just be aware that if you follow the
formulae it will be big. No problem though as you can still make it small and get some of the benefits.
If it is going to be smaller though it should have a wider run in - as in metiz's picture.
The field is still open for augumentor tail pipe decreased apertures (thrust) or increased apertures ( pressure increase) etc - so
you can still have heaps of fun there.( should be able to make a smaller tricked out augmentor that gets most of a big augmentors benefits within certain parameters)
With the long engine you have a full size augumentor is going to be a bit akward in regards to attachment etc.
However in saying that - any augumentor is going to be better than none.
Metiz - a lot of drag behind that augumentor intake flare - cool picture though.
Take all what I have said with a grain of salt as I have never followed the augmentor formulae - just made up augmentors with whatever I had at hand and they still worked - maybe not efficently - but still they did the job.

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Re: augmenter for M40

Post by ganuganu » Wed May 04, 2011 2:13 pm

Jutte wrote:Hi ganuganu,
On most Pulse Jets the Augmentor is placed on the intakes - as the bigger the
Pulse Jet is ,the augmentor starts to get rather large in regards to a tail pipe augmentor.This gets to a point where there it can cause a serious drag problem.If you check out some of the French Snecma ecrevisse type of engines - when fully faired
only the intake was augumented.
However in saying that - yes you can still augment a tail pipe - just be aware that if you follow the
formulae it will be big. No problem though as you can still make it small and get some of the benefits.
If it is going to be smaller though it should have a wider run in - as in metiz's picture.
The field is still open for augumentor tail pipe decreased apertures (thrust) or increased apertures ( pressure increase) etc - so
you can still have heaps of fun there.( should be able to make a smaller tricked out augmentor that gets most of a big augmentors benefits within certain parameters)
With the long engine you have a full size augumentor is going to be a bit akward in regards to attachment etc.
However in saying that - any augumentor is going to be better than none.
Metiz - a lot of drag behind that augumentor intake flare - cool picture though.
Take all what I have said with a grain of salt as I have never followed the augmentor formulae - just made up augmentors with whatever I had at hand and they still worked - maybe not efficently - but still they did the job.
shall i use this calculated augmenter or not sir...orelse is there anything to be changed before implementing them..

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Re: augmenter for M40

Post by PyroJoe » Wed May 04, 2011 4:07 pm

Maybe look at a scaled down version of the Thunderchine augmentors. I think the M40 tail is sufficiently expanded and mixed, but the intake probably could use some augmentation.

Not sure how applicable my stuff would be to this one, the shorter tail pumps/rectifiers behave differently than what I typically use. Probably a noteable condition to watch for is that it avoids breathing in its last exhaust charge from the intake.

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Re: augmenter for M40

Post by hinote » Wed May 04, 2011 4:32 pm

PyroJoe wrote:Maybe look at a scaled down version of the Thunderchine augmentors. I think the tail is sufficiently expanded and mixed, but the intake probably could use some augmentation.

Not sure how applicable my stuff would be to this one, the shorter tail pumps/rectifiers behave differently than what I typically use. Probably a noteable condition to watch for is that it avoids breathing in its last exhaust charge.
One of the relatively undiscovered advantages of the intake augmentor is the fact that it can be tuned to increase the resonance in the intake itself. This would amount to "supercharging" at the intake and should increase power on its own--without regard to the augmentation effects.

BTW the "recuperator" on the Snecma Escopette was simultaneously a flow reverser, an augmentor and a resonance tuner for the intake. One could do worse than to try and emulate this effort IMO. It should be easy to tune this device using a sliding tube set (make it as tight as possible to reduce leakage) to find the best length. There are also numbers in the Escopette drawings to provide additional leads.

One additional note: The "recuperator" also cleans up the intake flow field because it captures most of the exhaust gases (high velocity=narrow flow column) but draws from the broad field of fresh air surrounding the intake during the inflow portion of the cycle.

I'd love to see a successful report by someone who has effectively developed this detail.

Bill

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Re: augmenter for M40

Post by metiz » Wed May 04, 2011 4:57 pm

Forgot about that one...Anyone have a link to Escopette documentation?
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Re: augmenter for M40

Post by PyroJoe » Wed May 04, 2011 6:47 pm

Here is one I have:
Attachments
escopette.jpg

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Re: augmenter for M40

Post by PyroJoe » Wed May 04, 2011 6:50 pm

The unexpanded length of the tailpipe is near equal to the intake length on the M40. Maybe an apples to oranges?
Attachments
m40esc.JPG
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Re: augmenter for M40

Post by Jutte » Wed May 04, 2011 10:06 pm

Hi ganuganu,
Hey ganuganu I'm just Jutte not "sir" :lol:
Yes you can still use it with the sizes you have - or you can make it shorter for
size convience.

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Re: augmenter for M40

Post by ganuganu » Thu May 05, 2011 2:49 am

then making an augmenter for the exhaust pipe is not necessary i should make an augmenter for the intakes am i right..can anyone explain me what is an "Snecma Escopette"..and for what they are used..

@jutte how can i make it small by what formulas i can scale it down...sorry dont get angry on me iam a beginner..

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Re: augmenter for M40

Post by ganuganu » Thu May 05, 2011 3:20 am

PyroJoe wrote:Maybe look at a scaled down version of the Thunderchine augmentors. I think the M40 tail is sufficiently expanded and mixed, but the intake probably could use some augmentation.

Not sure how applicable my stuff would be to this one, the shorter tail pumps/rectifiers behave differently than what I typically use. Probably a noteable condition to watch for is that it avoids breathing in its last exhaust charge from the intake.
i cannot find any file or link in thunderchine sir..it says that the following attachment does not exist..

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Re: augmenter for M40

Post by Jutte » Thu May 05, 2011 11:18 am

Hi ganuganu,
Hey that's cool - we are all beginners in something!
There is no 'real' formulae for scaling down augmentors. You're going to have to be creative and make something up
that works.You could use mathematical formulae - or just grab some metal and start bashing and welding away!
I would go for roughly the flared opening of the original worked out size that you have done and shorten the length.
Basically it depends how much metal you have and what you can afford.If your teachers ask for hard data - do a thrust test before ,and then after it has been augmented.
The Escopette was a Pulse Jet designed by the French Snecma( jet/aircraft manufacturers)company in the 1950's . It powered a sailplane (glider)-and I think it was also tested to .85 mach.( The engine not the sailplane!)
Also have a good read of the famous...
Valveless Pulsejet Engines 1.5
-- a historical review of valveless pulsejet designs --
by Bruno Ogorelec
- there is some good ideas in there of what has been done.
Attachments
thunderchine-pulsejet-plans.pdf
(1.89 MiB) Downloaded 640 times

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Re: augmenter for M40

Post by ganuganu » Fri May 06, 2011 2:48 am

Jutte wrote:Hi ganuganu,
Hey that's cool - we are all beginners in something!
There is no 'real' formulae for scaling down augmentors. You're going to have to be creative and make something up
that works.You could use mathematical formulae - or just grab some metal and start bashing and welding away!
I would go for roughly the flared opening of the original worked out size that you have done and shorten the length.
Basically it depends how much metal you have and what you can afford.If your teachers ask for hard data - do a thrust test before ,and then after it has been augmented.
The Escopette was a Pulse Jet designed by the French Snecma( jet/aircraft manufacturers)company in the 1950's . It powered a sailplane (glider)-and I think it was also tested to .85 mach.( The engine not the sailplane!)
Also have a good read of the famous...
Valveless Pulsejet Engines 1.5
-- a historical review of valveless pulsejet designs --
by Bruno Ogorelec
- there is some good ideas in there of what has been done.
in this thunderchine document,the dimensions are not given simply the layout is given for construction..so shall i use this augmenter to attach to my(intake) M40 pulsejet engine..

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