Forum: Technology

I was looking at the MiG-19 and noticed that it looked like it only had one nozzle, despite having two engines. Am I mistaken in the observation? Would something like that work? A single nozzle would mean less maintenance than two nozzles. Also, if one engine went out, there would be considerably less asymmetric yaw because the thrust is still being expelled from a single, centrally-placed nozzle.

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IIRC, it was 2 nozzles mounted internally, which sent their exhaust through the tailpipe.

I have a 1/32 scale model of one. It has both engines with long internal tailpipes that end just inside a sort of figure 8 like opening. It is kind of deceiving at angles but definitely has two tail pipes. It is strange that the afterburners seem to be so far inside of the plane, at least going by the assembly of the model's engines.

Here's a view of one:

While the two engine-one nozzle theory sounds good, wouldn't it involve a lot of expensive heat resistant materials to make the larger funnel like portion of the fuselage before the nozzle itself?

To put it mildly, no. It would not work for any sort of high performance engine, esp not an afterburning one. I do(did, company can't decide) heat transfer for a living so allow me to explain.

You're going to have jet impingement on a wall. That jet impingement generates some large heat transfer coefficients, on the order of 3000 BTU/h*ft2*R. Needless to say that's huge. This wouldn't be terrible in a non afterburning engine except that it'll light the back end of your jet up like a Christmas tree in the IR spectrum. If you start afterburning, you're forcing temperatures over 2500 F, maybe close to 3000 F. You would need not only extremely heat resistant materials, you'd also need to film cool that region. That means robbing more flow from the compressor to cool that part of the casing and it wouldn't be a small amount to cool that area. You'd also have to worry about mixing losses which would be a huge concern as well as exhaust uniformity. You'd end up adding length, weight, complexity, compressor losses, and increase IR detectibility.

It's a pretty cool idea, but it wouldn't work well in a fighter, something like a B-2? Yeah that could be done, but not for fighters.

StolichnayaStrafer wrote:

wouldn't it involve a lot of expensive heat resistant materials

In a word...Titanium. I don't know if that's what they actually used, but it seems plausible. Several aircraft use titanium exactly for this very reason. Ceramic material actually works quite well also.

Kryptonite

OL

Dilithium crystal

(Star Trek, anyone?)

How about some Unobtainium? God why did I ever watch "The Core"?

Time for a redesign. What if we used a two-piece nozzle system like the F-22 has? Two opposable plates stretch across the backs of both of the engines and can be narrowed and widened as needed for the given flight conditions. The back of each plate can be serated for steath considerations if so desired.

*double post*

the single nozzle would need to have an exit area of at least BOTH nozzles combined, figure in interference between the engine exhausts, and it would need to be even greater to not cause restriction. My Two Cents

TEG

I want my plane's engines designed by TEG, MacGyver, and Chuck Norris!

If I couldn't get MacGyver and Chuck Norris, then TEG would do just fine by himself. Thanks for always being able to explain what keeps me going up and forward while I'm up there TEG. Salute

Suck, squeeze, bang, blow.... LMAO

In Thrust We Trust - TEG

In Thrust We Trust, indeed!

Some people complain that the plane is too loud. Really, it doesn't bother me. It's when I'm flying along and everything suddenly got quiet, that I would start to worry.

Forum: Technology

Two Engines, One Nozzle