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Aviation industry tries to go green

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Re: Aviation industry tries to go green

#11

Post by zabzonk »

newnewpdro wrote: post #7
WalterBright wrote: post #4

Earlier quoted context omitted.

Yup. Piston aircraft engines indeed need tons of maintenance. A huge number of moving parts coupled with trying to minimize the weight and maximize the power is the cause. In WW2 the Germans fitted aircraft engines to their tanks, which worked great when the engines ran, but too often they didn't due to battlefield conditions. (Germany was also terribly short of avgas, which crippled those tanks.)

> In WW2 the Germans fitted aircraft engines to their tanks, which worked great when the engines ran, but too often they didn't due to battlefield conditions. (Germany was also terribly short of avgas, which crippled those tanks.) This sounded interesting so I skimmed the tanks mentioned in [0] and only found mention of prototypes exploring use of a turboshaft engine [1] from [2]. [1] explicitly states "none of these…

Don't know about the Germans, but the British used modified aero engines quite extensively in tanks - https://www.wikiwand.com/en/Rolls-Royce_Meteor

Re: Aviation industry tries to go green

#12

Post by WalterBright »

newnewpdro wrote: post #7
WalterBright wrote: post #4

Earlier quoted context omitted.

Yup. Piston aircraft engines indeed need tons of maintenance. A huge number of moving parts coupled with trying to minimize the weight and maximize the power is the cause. In WW2 the Germans fitted aircraft engines to their tanks, which worked great when the engines ran, but too often they didn't due to battlefield conditions. (Germany was also terribly short of avgas, which crippled those tanks.)

> In WW2 the Germans fitted aircraft engines to their tanks, which worked great when the engines ran, but too often they didn't due to battlefield conditions. (Germany was also terribly short of avgas, which crippled those tanks.) This sounded interesting so I skimmed the tanks mentioned in [0] and only found mention of prototypes exploring use of a turboshaft engine [1] from [2]. [1] explicitly states "none of these…

I didn't mean a gas turbine engine, but a piston engine designed for aircraft. (Gas turbines don't run on avgas.)

With a quick look I can't find a cite for my claim, just that the British did use Merlin aviation engines in some of their tanks.

Re: Aviation industry tries to go green

#13

Post by mtreis86 »

nradov wrote: post #5

There are a number of other initiatives underway to reduce greenhouse gas emissions from commercial aviation. Synthetic kerosene can be manufactured using power and heat from renewable energy sources. Electric motors can be used for taxiing so that the turbines only have to be started immediately before takeoff. The electromagnetic catapults used on the latest Navy aircraft carriers can be scaled up to launch redesig…

Shutting turbine engines down and starting them up is when most of the routine wear happens, it may actually be cheaper and greener to use the fuel.

Re: Aviation industry tries to go green

#14

Post by Ididntdothis »

cgrealy wrote: post #8

The big win would obviously be electric aircraft, but I doubt we'll see that in my lifetime (barring a massive breakthrough in battery technology). The problem is even the best batteries have a much lower energy density compared with traditional fuels. Also, a battery that weighs 100kg when full weighs pretty much 100kg when empty. Real Engineering did a pretty good video on the topic https://www.youtube.com/watch?v=…

I think hydrogen would be a candidate but then you have to deal with cooling.

Re: Aviation industry tries to go green

#15

Post by newnewpdro »

WalterBright wrote: post #12
newnewpdro wrote: post #7

Earlier quoted context omitted.

> In WW2 the Germans fitted aircraft engines to their tanks, which worked great when the engines ran, but too often they didn't due to battlefield conditions. (Germany was also terribly short of avgas, which crippled those tanks.) This sounded interesting so I skimmed the tanks mentioned in [0] and only found mention of prototypes exploring use of a turboshaft engine [1] from [2]. [1] explicitly states "none of these…

I didn't mean a gas turbine engine, but a piston engine designed for aircraft. (Gas turbines don't run on avgas.) With a quick look I can't find a cite for my claim, just that the British did use Merlin aviation engines in some of their tanks.

I couldn't find mention of anything else aviation-related in the per-tank pages, and the Maybach WWII engines page [0] doesn't speak to it either.

Do you have any good references we can check out?

[0] https://en.wikipedia.org/wiki/List_of_WWII_Maybach_engines

Re: Aviation industry tries to go green

#16

Post by newnewpdro »

zabzonk wrote: post #11
newnewpdro wrote: post #7

Earlier quoted context omitted.

> In WW2 the Germans fitted aircraft engines to their tanks, which worked great when the engines ran, but too often they didn't due to battlefield conditions. (Germany was also terribly short of avgas, which crippled those tanks.) This sounded interesting so I skimmed the tanks mentioned in [0] and only found mention of prototypes exploring use of a turboshaft engine [1] from [2]. [1] explicitly states "none of these…

Don't know about the Germans, but the British used modified aero engines quite extensively in tanks - https://www.wikiwand.com/en/Rolls-Royce_Meteor

That's pretty smart, using de-tuned aviation engines.

But unlike what WalterBright is describing, these were appropriately reconfigured to not require high-octane fuel.

Re: Aviation industry tries to go green

#17

Post by WalterBright »

newnewpdro wrote: post #15
WalterBright wrote: post #12

Earlier quoted context omitted.

I didn't mean a gas turbine engine, but a piston engine designed for aircraft. (Gas turbines don't run on avgas.) With a quick look I can't find a cite for my claim, just that the British did use Merlin aviation engines in some of their tanks.

I couldn't find mention of anything else aviation-related in the per-tank pages, and the Maybach WWII engines page [0] doesn't speak to it either. Do you have any good references we can check out? [0] https://en.wikipedia.org/wiki/List_of_WWII_Maybach_engines

I have a few hundred books on WW2, it's possible I'm mis-remembering it. I am ashamed :-(

Re: Aviation industry tries to go green

#18

Post by cgrealy »

moltar wrote: post #9
cgrealy wrote: post #8

The big win would obviously be electric aircraft, but I doubt we'll see that in my lifetime (barring a massive breakthrough in battery technology). The problem is even the best batteries have a much lower energy density compared with traditional fuels. Also, a battery that weighs 100kg when full weighs pretty much 100kg when empty. Real Engineering did a pretty good video on the topic https://www.youtube.com/watch?v=…

World's first fully electric commercial aircraft takes flight in Canada https://www.theguardian.com/world/2019/dec/11/worlds-first-f... Of course far from intercontinental jet, but it’s a start :)

Did you watch the video I posted? It specifically talks about converting a small aircraft and says you could get "about 20 minutes".

Building an actually useful commercial plane (i.e. something along the lines of 737 or A320) is an order of magnitude more difficult, in fact, basically impossible with current battery technology.

Re: Aviation industry tries to go green

#19

Post by WalterBright »

chrisseaton wrote: post #6
nradov wrote: post #5

There are a number of other initiatives underway to reduce greenhouse gas emissions from commercial aviation. Synthetic kerosene can be manufactured using power and heat from renewable energy sources. Electric motors can be used for taxiing so that the turbines only have to be started immediately before takeoff. The electromagnetic catapults used on the latest Navy aircraft carriers can be scaled up to launch redesig…

> Electric motors can be used for taxiing so that the turbines only have to be started immediately before takeoff. I thought that this was pointless because the engines needed that time during taxiing to warm up properly anyway? If you moved them to the runway electrically they'd then just need to sit there burning fuel for five minutes to warm up. Naval jet fighters, which launch through steam or electronically and…

I know that for piston engine aircraft, it is critical that the engine be properly warmed up before takeoff. Otherwise, the engine would likely stall shortly after liftoff, leading inevitably to a crash. This is a common cause of accidents.

I don't know specifically about jet engines, but as the engine is designed to run while hot, and metal expands when hot, I'd be quite surprised if it wasn't necessary to warm them up before full power, too.

Drag racing engines will often be warmed up using some sort of electric blanket.

Even for your car, it's a bad idea to floor it while the engine is cold.

Re: Aviation industry tries to go green

#20

Post by [deleted] »

nradov wrote: post #5

There are a number of other initiatives underway to reduce greenhouse gas emissions from commercial aviation. Synthetic kerosene can be manufactured using power and heat from renewable energy sources. Electric motors can be used for taxiing so that the turbines only have to be started immediately before takeoff. The electromagnetic catapults used on the latest Navy aircraft carriers can be scaled up to launch redesig…

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