engine installation 2

[stage81]

Hi,

http://www.eng-tips.com/threadminder.cfm?pid=31

Can someone explain why we install the engines on the upper part of the fuselage (is there is a problem of boundary layer, etc.)

Thanks

 

[Sparweb]

Hi Stage 81,
You link directed me to the overall forum group, not to a specific thread. It should end with a 6-digit reference number. "pid=31" is the Aerospace Eng Other Topics forum.

Not knowing what context you've seen or are asking about, I can't give you a specific answer other than a big generalization.

Props: It's unhealthy for them to strike the ground.
Jets: It's unhealthy for rocks to get in them.

If you can give a detailed explanation of why your asking (or just vague curiosity) then we can offer a more specific answer.

STF

 

[tbuelna]

It is not universally true that all aircraft have engines installed "on the upper part of the fusealge".

Some have the engines installed at the front of the fuselage (single recip engine and turboprop aircraft), some have the engines installed inside the fuselage (many military jet fighter aircraft), some have the engines installed under the wings (most commercial jet aircraft), some have the engines installed above and forward of the wings (twin piston engine and turboprop GA aircraft), and a few even have the engine installed in the lower rear section of the airframe (the MD500 helo).

 

[stage81]

Thank's for your response, but is there a rule to install the engine in upper or lower part of the fuselage? (minimize noise for exemple or minimize turbulence, more aerodynamic efficiency, boundary layer, etc.)

 

[KENAT]

There are a whole bunch of factors to be considered in deciding where the engines end up, aerodynamic, structural, flight mechanics, ease of servicing, acoustics, 'stealth' (not just radar also heat and other signatures), safety...

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[dgapilot]

Don't forget, many times it has nothing to do with aerodynamics, and more to do with reducing FOD damage. Jet engines are great vacuum cleaners and will pick up lots of stuff off the ground! Aircraft with propellers have minimum prop clearance issues for much the same reason, only they are worried about prop damage rather than engine damage.

 

[rb1957]

as Kenat said, there are a multitude of factors dealing with engine locations. all have pros and cons. mind you i`m not sure i understand "the engine in upper or lower part of the fuselage" ... do you mean like on a pylon ? if it is close to the fuselage, like a fighter jet intake then you`ll see a splitter plate (to separate the boundary layer) one consideration is high AoA manoeuvre performance (getting air into the engine). i think that since you see make different configurations then no one configuration is a clear winner, all are compromises and all perform well enough.

another day in paradise, or is paradise one day closer ?

 

[tbuelna]

Large pieces of FOD can definitely be a hazard for jet aircraft with engine intakes close to ground level.

http://www.youtube.com/watch?v=vHtgXsIxA8A

 

[3DDave]

Sometimes a high mount is advantageous.

https://www.youtube.com/watch?v=C80grd2CrTI

 

[KENAT]

Yep, a big part of my 'safety' was relating to FOD ingestion though there are other factors under the safety banner.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​