Torque vs HP???

[RMCIII 838]

some of the test procedures to determine rated power and life for internal combustion engines involve accelerated power ratings to shorten test times for component wear characteristics, With diesels it is not uncommon to start a green engine, 5 min breakin at no load and then go to rated power (100%) and then add 10% fuel, total of 110% fuel and then run for 1000 hrs. with shutdowns at 250 hr intervals for oil/filter changes and dyno maintainence, test complete at 1000hrs. and engine disassembled for evaluation components. Gas engines typically have a 4 hr breakin and then run at peak hp and peak torque for specific time intervals before end of test power verification and disassembly for inspection.

But again, you are talking about gas or diesel. These engines are built ahead of time, knowing what the "expectations" of the output will be. When a Pratt & Whitney, GE, JP, ect. jet engine is mfg. It is put together with the understanding that an AB unit will or will not be applied to the back of it. Once they know what the specifications are, then they assembled, to wither withstand AB or not. < Although that itself is a "relative term" understanding the amount of additional stress that is applied to an engine when an AB unit is attached, all becomes a factor of additional thrust or "ABOVE 100%" the engine will perform. Have you ever heard what a jet engine sounds like pre AB? The rpm's, depending on the engine, reside between 12 - 15K. Now add the AB, and the RPM's increase due to additional air needed to be used for the AB units.

I realize that in "engine theories" going clear back to Brown who created the first combustion engine, many have added to the development and technology, at that time. An Afterburning Jet engine does not fall into typical engine performance. The AB section and "fuel tubes" are the only factors that regulate how much additional air/oxygen the fire will require. Therefore requiring additional air to be supplied by the turbines. Suck, bang, blow, go... Jet engines 101.

Final thought, if I add AB to a typical 747 jet engine, will it not produce additional thrust? I know it will, and the engine, will be operating above it's 100%.

[shorts 182]

I have very limited turbine/jet experience but do understand the theory, the afterburners are just like taking a "stock" engine and adding air and fuel to increase power. Example; Cummins B5.9L 12v started @ 165hp in Dodge pickups, same engine in marine trim @300hp, give it to the truck pulling guys and they are making 2000 hp + and claim it to be reliable as it doesn't need an overhaul after a 300' pull, just keep adding air(boost) and fuel, a few $ for aftermarket parts doesn't hurt either.

In my mind the fact that all of the motion is rotary instead of reciprocal is what makes jets more reliable, also if my understanding is correct the AB is more like a roman candle in that the additional fuel is added at the back end behind the basic engine and not run thru the turbine to increase thrust without adding to the temp/combustion/pressure induced stresses.

 

All neet stuff and it continues to fascinate me as information and material technology races forward to smaller and lighter power units are continually developed.

 

In reply to jet engine testing, unfortunately the closest I have ever been is the base access road at MacDill AFB while they were running up a F16 after overhaul, I didn't that it was in my best interest to get any closer and have to talk with the MP's as I was just a civilian contractor servicing equipment at the bx.  I'm just a reciprocating engine guy, suck squeeze bang blow but always have been interested in turbines just never had the opportunity to make the change

[RMCIII 838]

shorts- additional fuel is added, at the rear of the jet engine... But it still needs the additional oxygen/air flow to support the additional fuel being burned. That still comes through the main turbines. Without the additional oxygen, to support the fuel for the fire, it just becomes wasted fuel. But correct on the overall theory. Sorta like a wood burring stove. You can add all the wood you want to ambers that are nice and hot. Shut the door, and keep the ash drawer closed, the wood will eventually burn. But open the ash drawer and watch the fire ignite and listen to the oxygen begin to accelerate through the ash drawer. A little to simple of an example, but same principles.

[oaktown1987 82]

The higher the rpm the more power u make torque is twisting force and and happens around 3000 rpms depending

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