BaldEagel

Just to throw one thought into the mix, higher temp air will hold more vapour, does it not follow that the higher the EGT the more fuel has been burnt ergo more thrust?

Mike

highhorse

My Feedback: (2)

Hmmmmm. More fuel burned = higher egt, but not always the other way around.

Henke Torphammar

I found that removeing the hood infornt of the engine would lower the EGT by as much as 60°C and following through the whole rpm register. The turbine performs just as well but with a much lower EGT.

BaldEagel

Henk

Did you notice any difference in fuel consumption? i.e. efficiency? just trying to get a complete understanding of what happens.

I am leaning towards the thought that because we have a fuel driven compressor the turbine will draw in as much air as it needs to produce the power comanded, therefore the temp and fuel economy may be the variable, not the ducting, what do others think?

Mike

Nhalyn

My thought is that :
- If there is a good duct or air feeding to the engine, this one have no effort to do to suck enough air and so all "power" available is used to thrust.
- If the air feeding of the engine is not good (turbulent, not enough, or other reasons), the engine have to use a part of the available power to suck some air, and this lead to less overall efficiency of the engine.

gunradd

My Feedback: (9)

The old CJ610 lear jet engines have inlet guide vanes (IGVs) that move to direct air onto the first stage compressor blades. That right thier tells allot.

Also on any full scale turbine I work on the lower the fuel flow and cooler the engine is with the max RPM for the day reached the better. When engines are close to overhaul they start to hit the temp limit and have higher fuel flow.

BaldEagel

Nhalyn

To a certain degree I agree with what you say, but with our small size turbines and short time usage would we notice the difference, In reality I am asking if anyone has some hard evidence of what advantages a full duct system has.

Mike

Henke Torphammar

No, I only read of the FADEC display, I have no tools for messuring fuel economy in a good enough way.

BaldEagel

Just thought you may have noticed more fuel left in the tank after a normal length flight?

Mike

Henke Torphammar

Actually I do land with more fuel on the later flights but ican NOT draw any conclutions as throttle management is a large factor and two flights are not the same :-P