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dirschau t1_ja6wr10 wrote

Reply to comment by kdieick in Eli5: why are some airplane jet engines under the wings and some on the vertical stabilizer? by Sad-Carrot-4397

>Why doesn't every car look the same, have the same engine, and use the same tire size?

Well... Why? What design requirements dictate the specific design choices?

This is a complete non-answer.

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kdieick t1_ja6xowr wrote

> Well... Why? What design requirements dictate the specific design choices?

Similar ones. For a car, engine, and tire size: power, fuel consumption, grip, suspension, stability, cornering, ride comfort, cost.

I already listed some flight requirements that dictate design choices for a plane:

> amount and location of weight, payload, thrust, control, and other flight characteristics

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dirschau t1_ja6ycjn wrote

Yeah, exactly, you're just listing stuff, you're not even trying to actually say which ones matter for what.

Why do some cars have an engine in the front and others in the back? Why do some planes have straight wings and some swept? Why are missiles pointy but torpedoes round?

bEcAuSe ReAsOnS LOL

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kdieick t1_ja6zky6 wrote

> Why do some cars have an engine in the front and others in the back?

Mass distribution and the torque that can be generated on a driveshaft depending on whether the drive wheels are at the same end as the engine or the opposite end. Mass distribution affects stability and control, just like it does with a plane, like I said.

Yes, all of airplane design can't be explained in a reddit comment. Center of gravity, lift, and the tail force to control the plane are the reasons for choosing the engine location on a plane. Otherwise an unbalanced plane is difficult and dangerous to fly, with unstable recovery modes. The center of gravity, center of lift, and the forces applied by the control surfaces have to be balanced to fly the plane with stability. Large, heavy engines are usually placed near the center of mass of the plane. Engines placed elsewhere have to be balanced in other ways to keep the whole plane level and well controlled.

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dirschau t1_ja709yy wrote

This sounds like a reasonable ELI5 explanation, why not put that as the top level comment?

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