Tighter airvalves?

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ace_fedde
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Tighter airvalves?

Post by ace_fedde » Sun Nov 08, 2009 9:39 pm

Reading an old thread, I think Mike's first thread(?), I was looking at this picture and got an idea.
JAVFE%202[1].JPG
In Mike's design the intakes are placed so that they don't blow at/in each other. Now what will happen if the intakes blow at each other:
airvalve.JPG
airvalve.JPG (7.14 KiB) Viewed 9088 times
Would it make tighter airvalves, causing higher combustion pressure in the CC?

Fedde
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metiz
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Re: Tighter airvalves?

Post by metiz » Mon Nov 09, 2009 12:13 am

I think this will stop the engine from breathing properly; it has nowhere to put its gasses and more importantly, suck in fresh air. The aditional pressure is likely going to mess up gassflow and stop the engine from running all together.
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Re: Tighter airvalves?

Post by ace_fedde » Mon Nov 09, 2009 5:16 pm

metiz wrote: ...it has nowhere to put its gasses..
Well, that's exactly what I meant to happen. Like in a valved PJ.
metiz wrote: ...it has nowhere to suck in fresh air...
I don't think so. Augmented intakes also don't breathe through the augmentors but from the sides, that is pressure-logic.
I am just afraid that still a part of the combustion gasses will escape and form a cloud around the intakes. Of course the PJ will then breathe in exhaust gasses and die :(
metiz wrote: The aditional pressure is likely going to mess up gassflow and stop the engine from running all together.
I think not. It will run like a valved PJ. Higher combustion pressure, more thrust out of the same length. But not anymore with inlet restricting, efficiency decreasing, valves.

Let's build one :D , I'll do the welding :wink:

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Re: Tighter airvalves?

Post by metiz » Mon Nov 09, 2009 5:42 pm

ace_fedde wrote: Let's build one :D , I'll do the welding :wink:
Fedde
ha! you're on! Whip up some plans and I'll build it....now if only I had some injectors :D
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Re: Tighter airvalves?

Post by PyroJoe » Mon Nov 09, 2009 5:50 pm

Something to keep in mind is that straight inlets shoot the exhaust charge clear of the intake area for some distance, so the engine isn't re-breathing much of the exhaust. Happy welding :wink:

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Re: Tighter airvalves?

Post by ace_fedde » Mon Nov 09, 2009 6:08 pm

PyroJoe wrote:Something to keep in mind is that straight inlets shoot the exhaust charge clear of the intake area for some distance,
Joe, did you get that I want to shoot the exhaust charge right into the other inlet?
So that the inlets cannot breathe out, only breath in. Still a bit worried about breathing in exhaust gasses, might have to do some more thinking before welding :wink:

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Re: Tighter airvalves?

Post by metiz » Mon Nov 09, 2009 7:00 pm

This is a quickly sketched engine, to scale, that could be used for this app. I can't make bend pipes in sketchup so you'll have to inmagine those :)
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facing intakes sketch.jpg
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Re: Tighter airvalves?

Post by ace_fedde » Mon Nov 09, 2009 7:13 pm

I'm on it, I'm on it.
I also have some idea in mind, start thinking about the Kenny 4-inlet :D :D . Sketches will come later.

Btw, I have a "pijpenbuiger" (pipe bender). I have to check one of the coming days for which diameter pipe it is, then we can scale the design.

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Re: Tighter airvalves?

Post by ace_fedde » Mon Nov 09, 2009 7:15 pm

Joost,
I called today for the injector pipe, still no answer...
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Re: Tighter airvalves?

Post by ace_fedde » Mon Nov 09, 2009 8:21 pm

In the next drawing you can see what my concern is. When the two exhaust streams collide and block each other, some gas will escape sideways (but won't have speed). That's exactly the area where the PJ is inhaling from:
2 airvalves.JPG
2 airvalves.JPG (11.02 KiB) Viewed 8990 times
With four intakes the exhaust gasses have less room/directions to escape, see left in the drawing down here:
4 airvalves.JPG
If we catch those gasses with a funnel (see right), we might prevent the PJ from inhaling exhaust gasses.

So? a Kenny?
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Re: Tighter airvalves?

Post by PyroJoe » Mon Nov 09, 2009 9:01 pm

I like the kenny idea,
Here is what came to mind at first look of the design, basically using a plate with a hole a little larger than the flare to help seperate the exhaust from the intake, probably draggy. May work as is, ha.
Attachments
shen1.JPG

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Re: Tighter airvalves?

Post by ace_fedde » Tue Nov 10, 2009 10:58 am

Joe,
In your design I think the exhaust gasses still have to much room to escape.

Metiz,
What you think of this one:
viewtopic.php?f=3&t=3044&st=0&sk=t&sd=a ... =15#p39668
Not big enough? :arrow:
viewtopic.php?f=3&t=3044&st=0&sk=t&sd=a ... eld#p37719

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Re: Tighter airvalves?

Post by ace_fedde » Mon Dec 07, 2009 6:48 pm

Metiz,

These elbows I was planning to use for our experiment:
P1010378.JPG
The id of the tube that is meant to shift in is 13 mm. The elbows have at the ends an id of 15 mm, like the od of the tube.
At the bend they have an id of 13 mm.
The length of the centerline is around 35 mm.

As seen at the next photo, the dia of the CC should be around 70 mm if the intakes would have a lenght of 55 mm. On this photo I've (crudely) drawn the intakes with a lenght of 55 mm.
P1010379.JPG
It would be nice if the intakes could be slightly longer, and perhaps the CC's diameter could be around 70 or 80 mm.

Unfortunatly that doesn't fit your initial design :( which you send me earlier by PM:
facing inductors.JPG
Could you...?

Thanks! Fedde
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Re: Tighter airvalves?

Post by metiz » Mon Dec 07, 2009 7:12 pm

I don't think I can make the cc fatter AND make the intakes longer, only shorter with the given D of 13 mm...let me think about this for a while...brb :)
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Re: Tighter airvalves?

Post by metiz » Tue Dec 08, 2009 7:29 pm

Right. slapped on a straight TP on the Minikenny. here are the dims. Nothing fancy though and CERTAINLY NOT to scale
(all done in mm)
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straight minikenny.JPG
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