Round exhaust exits vs fishtail

My car doesn't have exhaust stacks sticking out of the sides of the vehicle, plus they run through a catalytic converter & muffler. Not a good comparison.

 

So if a flatulent man walking down the street gains 1 mph from his rear exhaust, the argument is that the accelarated rear exhaust has no part in the speed increase. More likely the magnetic relation of the poles to Satuns ring or some other arcane mathematical theorum.

 

He gains 1 mph in order to avoid the exhaust behind him and not to smell his own output.



You seriously believe the exhaust from the piston engine creates thrust that increases the velocity of the aircraft directly in the Newtonian sense of action and opposite re-action?

The fishtail exhaust increases the velocity of the gases and helps the volumetric efficiency of the engine, resulting in more power, resulting in more thrust. The extra exhaust gases and the redirected exhaust gases energize the boundary air layer and reduce drag, resulting in a higher thrust to drag ratio, resulting in higher speeds and acceleration.

The exhaust pressure from the engine is negligible.

How many lbs/kilograms of thrust do you suppose that piston engine exhaust produces ?

 

http://www.flightglobal.com/pdfarchive/view/1940/1940 - 0876.html

I guess if you scale it up enough, you do get some slight effect. And that's exactly what this is. A slight effect. They do mention in the article that they simplify the calculation by incorporating it into the brake horsepower at the airscrew.

I was blinded to the science by my rage against you saying the Bf-109 was better in other threads. I took this as an implication that you thought that better machines should win wars (Which you never said, but it conjured the idea). It's better people that win wars. Never the machines. Shaka Zulu defeated the British, with their rifles and such, with spears and hide shields because he and his people were better warriors. This was in spite of the fact the British had the "better machines." It's the reasons you fight and the morals you choose that decide the outcome. Now that you know one of my pet peeves, I hope we understand each other a little more.

 

A certain massive numerical disparity might have had something to do with it, don't ya think?

 

Yeah, I thought the same thing when I read that

Well, when Mr. Karzai is enjoying his retirement in suburban Washington (Alexandria, VA?), will the narrative be that the Taliban and indigenous resistance in Afghanistan were "better" than the ISAF guys?

As a good friend of mine says: "The man [Karzai] has excellent tailors!" And it's true. I have been betting that he will go to Paris. If I had his money stashed away in banks, I would!

Really we all know that the US and allies will creep out of there ASAP, and leave the native folk to their rather sad fate. As soon as it's politically possible, LOL

But on topic: piston-powered plane exhaust surely has a rather minimal effect on performance, I'd guess

I gotta go see this movie this weekend.

 

Edit: What's up with the naptha explosions all the time? Hollywood spets-effect guys need to chill out and and not have every explosion be full of flames. Jeez. They like to burn mothballs, if you know what I mean

 

Why Red... you actually must have done some research and reading!

Comparing the firing of a Martini-Henry against several thousand charging Zulus......

 

You are talking about Islandlwana?
Day 2 was Rorkes Drift: Zulus lost that fight.
And they lost the war.

Nah, ya couldn't be.
Why go off topic and get me all confused?

 

Not me specifically Looseleaf, but all the engineers & aircraft designers of then & today. & to answer your question, (which has already been answered), there is this...

As it turned out, exhaust thrust was very important.
A well-designed jet (ejector) exhaust system can capture a considerable amount of this energy, and can easily increase rated horsepower by 10 per-cent or more. At 25,000 feet a 400-mph airplane could expect a gain of around 20-25 mph… and it cost almost nothing.

http://www.wwiiaircraftperformance.o...-38-wayne.html



Mumble;
I was blinded to the science by my rage against you saying the Bf-109 was better in other threads.

Mumble, they are just machines, not worth all the emotion, Peace & Love.

 

That is exactly what I said. You're use of the word "thrust" is confusing.

It is not the "thrust" of the exhaust that directly propels the aircraft in the Newtonian sense of action and opposite reaction. It is the improvement in exhaust evacuation and volumetric efficiency of the engine that produces more power , producing more thrust. Also it is the energized boundary layer that contributes to lowering the overall drag.

The "thrust" of the exhaust does not push the plane faster is what I was trying to tell you.

I am getting the idea that English is not your first language?

 

nope...incorrect

Exhaust leaving the pipes at 1000mph into an airstream traveling less than half that speed has "thrust".

Your understanding of basic newtonian physics has failed you once again.....and often.

Read the link below and maybe you won't spew this incorrectness.

http://www.supercoolprops.com/articles/gwhitegearheads.php

 

Maybe I'm misreading loose here, but I think what he is saying is that while the exhaust pipes do produce a small amount of thrust, it is pretty much negligible.

 

By the way, that link is broken. Can you repost the correct link?

 

so, who is black hornet?

 

I bet it's YOU.

 

nahhhh i don't see flames coming out of that exhaust

 

No, it does not. No it has not. The fish tail exhaust LOWERS THE VELOCITY AND INCREASES THE FLOW OF GASES. CANNOT DO BOTH. STANDARD FLUID DYNAMIC LAW.

 

This is from your link Looseleaf, sorry, smoked yet again.


The argument presented is the fact jet thrust from the exhaust stacks is increased at the higher manifold pressure resulting in a higher air speed.
http://www.supercoolprops.com/articles/gwhitegearheads.php

Its pretty clear, Jet thrust from exhaust is increased, resulting in higher speed. In other words, the "extra thrust" is in fact what "specifically" creates & is responsible for the increased speed. It doesn't say something else.