Engines of Innovation

wrightwing · by **wrightwing** » 01 Dec 2018, 19:00

falcon.16 wrote:what advantages has new aetp engines comparing with current engines?

Has GO 2.0 some features from aetp engines?

The AETP motors are supposed to provide ~20% more thrust, ~50% more loiter time, ~35% increase in range, and improved acceleration/lower IR signature.

white_lightning35 · by **white_lightning35** » 02 Dec 2018, 03:45

As an interesting aside, I was talking to a P&W rep over the fall, and he told me they would rather have the US Gov just shelve the competition for new engines. He said their goal was to demonstrate that the current f135 has so much growth potential that the military won't waste billions on a competition for a new engine. Perhaps he was worried GE might have a winner?

popcorn · by **popcorn** » 02 Dec 2018, 04:28

white_lightning35 wrote:As an interesting aside, I was talking to a P&W rep over the fall, and he told me they would rather have the US Gov just shelve the competition for new engines. He said their goal was to demonstrate that the current f135 has so much growth potential that the military won't waste billions on a competition for a new engine. Perhaps he was worried GE might have a winner?

I'm sure he'd rather the USG waste billions exclusively on P&W engines. :mrgreen:

white_lightning35 · by **white_lightning35** » 02 Dec 2018, 06:19

Well that is a pretty good deal for them now

popcorn · by **popcorn** » 02 Dec 2018, 07:27

I'm curious how the 2-stream F135 can be modified to solve heat buildup in the jet's electronics which AFAIK is currently an issue for low speed low level flight?

sprstdlyscottsmn · by **sprstdlyscottsmn** » 02 Dec 2018, 07:34

No need. Wait for the next TR and then you have few and more capable components that allow for better cooling.

popcorn · by **popcorn** » 02 Dec 2018, 07:50

sprstdlyscottsmn wrote:No need. Wait for the next TR and then you have few and more capable components that allow for better cooling.

Just to clarify... the electronics will be modified to address the heating issue?

quicksilver · by **quicksilver** » 02 Dec 2018, 15:40

Power and cooling upgrades are common as jets mature and capabilities are added. F-35 will be no different.

markithere · by **markithere** » 18 Apr 2019, 16:10

How might Reaction Engines precooler help the F-135 engine for the F-35 in performance gains?

steve2267 · by **steve2267** » 18 Apr 2019, 18:53

markithere wrote:How might Reaction Engines precooler help the F-135 engine for the F-35 in performance gains?

Oh... man... it would turn it into an absolute rocketship!

Now to find the space, well, volume more likely, to fit all the liquid hydrogen necessary to run the precooler...

:drool:

marauder2048 · by **marauder2048** » 18 Apr 2019, 21:06

About the most exotic fuel I've seen (seriously) proposed for next gen fighters has been LNG in
part because the infrastructure for supporting it has advanced considerably over the last decade.

But you are more likely to see LNG as a coolant/fuel for a palletized, high-powered laser.

SpudmanWP · by **SpudmanWP** » 18 Apr 2019, 21:26

The problem with LNG is that even as a liquid, it is not dense. It has more energy per kg than gasoline but only has 2/3rds the energy per liter. What you will end up with is much larger tanks to go the same range vs AvGas. Then there is the whole issue of weight increases from larger tanks and other modifications needed to keep it in it's liquid form in flight.

https://en.wikipedia.org/wiki/Energy_density

marauder2048 · by **marauder2048** » 18 Apr 2019, 22:53

That's all true; what makes it attractive despite the energy density issue is the thermal
heat sink potential (~ 10X) relative to kerosene.

The argument goes that the total volume and weight gains are smaller that you would expect because you can
eliminate or compress the other cooling loops (ECS, engine) with LNG and as well as that portion of the non-usable
JP fuel volume that is there just for cooling.

https://www.researchgate.net/publication/280925005_Liquefied_Natural_Gas_as_the_Next_Aviation_Fuel

There are higher heat sink kerosenes out there and some techniques for de-oxygenating fuel that has
been used as a heat sink as well as coatings that are tolerant of coking. With this combination, you can
get JP-7 like heat sink capacity out of JP-8.

count_to_10 · by **count_to_10** » 18 Apr 2019, 23:26

SpudmanWP wrote:The problem with LNG is that even as a liquid, it is not dense. It has more energy per kg than gasoline but only has 2/3rds the energy per liter. What you will end up with is much larger tanks to go the same range vs AvGas. Then there is the whole issue of weight increases from larger tanks and other modifications needed to keep it in it's liquid form in flight.

https://en.wikipedia.org/wiki/Energy_density

So, a bullet into a tank full of jet fuel is containable. What happens when a bullet penetrates a LNG tank?

SpudmanWP · by **SpudmanWP** » 18 Apr 2019, 23:40

That all depends on what temp the LNG is kept at. Lower temp means lower pressure but higher weight of equipment used to keep the temp low.