Ask questions about aviation!

[Aircraft Enthusiast]

If you have a question about aviation, feel free to ask here. You can also come to the region Aircraft Enthusiast if you want to discuss aviation-related topics in our RMB

[Greater Somoiland]

Well I guess I’ll be asking the first question. Why do long range planes have more engines than short range ones? I get bigger planes have more fuel but couldn’t they just solve that with wider turbofans? Planes like the 747 and A340 are super-long-rangers, yet they have 4 tiny engines when it should be more efficient to just have 2 large turbofans

[Japuile]

How can you realistically describe your airline if I've never done something like that? The most important thing is that my country is really green - I have a battery, solar panels and wind turbines better than my entire region. If it was not possible to electrify planes, I still have biofuel.

[HarYan]

Opinion on the JAS 39 Gripen E/F?

[Crookfur]

Well I guess I’ll be asking the first question. Why do long range planes have more engines than short range ones? I get bigger planes have more fuel but couldn’t they just solve that with wider turbofans? Planes like the 747 and A340 are super-long-rangers, yet they have 4 tiny engines when it should be more efficient to just have 2 large turbofans

The short answer until the 2000/2010s is ETOPS.

Basically when a twin engine aircraft loses and engine it loses 50% of it thrust whilst a quad engine only loses 25%. Thus in an engine out scenario a quad jet can maintain a higher cruising speed and thus can travel further to reach a diversion airport within the 2-3 hour typical diversion time aircraft are certified for.
Thus quad jets are typically able to fly more direct routes over water rather having to stay closer to airports along the way.
It's only recently that twinjets have been able to match this and naturally the quads went out of production when the long range 777s and A350s came along (well apart from the A380 but it uses 4 of what we're the largest engines at the time, which was kind of also the case for the 747 on its launch).

The long answer is basically the same but with all the wonderful engineering details of the projects. The 747 launched with the industry standard engine and received newer engines over the years. The A340 used 4 trend 500s because its sibling, the A330 already used 2 of the largest available engines (trent 700s) and couldn't match the A340 requirements.
Yes I know the airbuses don't just use the RR trent series but I'll be damned if I can remember the umpteen CFM and GE options.

[Greater Somoiland]

Well I guess I’ll be asking the first question. Why do long range planes have more engines than short range ones? I get bigger planes have more fuel but couldn’t they just solve that with wider turbofans? Planes like the 747 and A340 are super-long-rangers, yet they have 4 tiny engines when it should be more efficient to just have 2 large turbofans

The short answer until the 2000/2010s is ETOPS.

Basically when a twin engine aircraft loses and engine it loses 50% of it thrust whilst a quad engine only loses 25%. Thus in an engine out scenario a quad jet can maintain a higher cruising speed and thus can travel further to reach a diversion airport within the 2-3 hour typical diversion time aircraft are certified for.
Thus quad jets are typically able to fly more direct routes over water rather having to stay closer to airports along the way.
It's only recently that twinjets have been able to match this and naturally the quads went out of production when the long range 777s and A350s came along (well apart from the A380 but it uses 4 of what we're the largest engines at the time, which was kind of also the case for the 747 on its launch).

The long answer is basically the same but with all the wonderful engineering details of the projects. The 747 launched with the industry standard engine and received newer engines over the years. The A340 used 4 trend 500s because its sibling, the A330 already used 2 of the largest available engines (trent 700s) and couldn't match the A340 requirements.
Yes I know the airbuses don't just use the RR trent series but I'll be damned if I can remember the umpteen CFM and GE options.

Interesting! Always wondered why but never considered engine loss requirements. I’d still make mine a twin engine tho

Opinion on the JAS 39 Gripen E/F?

Swedes make damn good planes. Great low-cost alternative for a nation looking to expand fighter capability. Of course, not as good as a stealth fighter, but for the cost it’s great

How can you realistically describe your airline if I've never done something like that? The most important thing is that my country is really green - I have a battery, solar panels and wind turbines better than my entire region. If it was not possible to electrify planes, I still have biofuel.

Japuile-Green Air is the best I could come up with. Search up Airbus zero emission if you wanna see plane examples