ORIGINAL: erazz
ORIGINAL: basimpsn
ORIGINAL: erazz
You're saying you want more thrust in smaller package, right? Even if the fuel draw is horrible?
Very generally a 40# engine in a 30# case will draw fuel like a 50# engine.
Well.. A smaller engine size(25#thrust for a S/M F-18E example) will put your throttle setting above haft the whole flight. But with a bigger engine your throttle just above idle & better fuel consumption.
P.s In my opinion
Hehe...
Efficiency doesn't work that way. Consider 2 engines. Both 40# thrust. One has a 120mm dia case and one has 100mm. The larger diameter will have better efficiency. It will use less fuel to push the same thrust.
I can understand why the thrust-to-weight or thrust-to-size numbers produce better sales. But on the efficiency side having a wide and short engine is much better.
Model Turbine engines have a long way to go before they reach the level of perfomance that can and has already been achieved in 4" diameter sizes. I have seen compression ratios of 6:1 and 300N thrust at FSC of 0.02 g/N/s in KJ sized package, using ceramic NGV and turbine, 600N with 2000 deg EGT.
Mainly the compressors and diffusors are radically different from the current CFD "optimised" designs. Combustors are simple but also very different.
Andre Baird