rootsair
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Shape Of 737 Tail: What's The Advantage?

Sun Mar 25, 2007 5:16 pm

Hi folks,

This question can also apply to ther A/c that have more or less the same shape of tail as the 737's: Fokker 70,100, E170, 190, etc.
As you may all know the 737(except the 100 and 200 series) have this sort of extension to the tail on its bottom part which I think is called the tail bumper!

I was wondering what the shape of the tail meant aerodynamically as compared to the othe type of tails without the bumpers is the case with most other commercial airliners. If its efficient then why do bigger a/c not have them or even similar sized a/c like the A320 ?
Would anyone be able to explain it to me,
Regards
BM



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[Edited 2007-03-25 10:18:11]
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jetmech
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RE: Shape Of 737 Tail: What's The Advantage?

Sun Mar 25, 2007 5:52 pm

Quoting RootsAir (Thread starter):
As you may all know the 737(except the 100 and 200 series) have this sort of extension to the tail on its bottom part which I think is called the tail bumper!

I think you have pretty much answered your own question RootsAir. The tail-bumper is there to protect the fuselage in case of over-rotation on take off and over-flare on landing. I believe that the fairing is an attempt to reduce the drag caused by the bumper, and that it has no aerodynamic benefit beyond this. The tail-bumper seems to only be fitted to 737's with longer fuselages.


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zanl188
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RE: Shape Of 737 Tail: What's The Advantage?

Sun Mar 25, 2007 9:15 pm

Quoting RootsAir (Thread starter):
As you may all know the 737(except the 100 and 200 series) have this sort of extension to the tail on its bottom part which I think is called the tail bumper!

I'm not clear on exactly what you're talking about. The bumper is on the bottom of the fuselage and protects the fuselage in case of a tail strike. I think what you're talking about though is the leading edge fairing of the vertical stabilizer where the stabilizer attachs to the fuselage - yes? If so the advantage to the leading edge fairing extension is this: When Boeing stretched the 737 fuselage for the -300, -400 and -500 series aircraft it needed more tail surface area to handle the engine out case with the bigger engines. Boeing could've produced a larger tail - but that would have meant spending quite a bit of money to retool the vertical stabilizer. Instead they chose to simply make the fairing bigger. If one looks closely at -100 & -200 series aircraft you'll see that the fairing is on those aircraft, just smaller.
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pilotaydin
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RE: Shape Of 737 Tail: What's The Advantage?

Sun Mar 25, 2007 9:19 pm

if you're talking about the extra fin extention on the tail, that is for stability about the vertical axis.....if the aircraft yaws over to one side, the fin helps with moment to recenter the track and direction of the a/c....

if you're talking about the tail skid, that's a different story
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Buyantukhaa
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RE: Shape Of 737 Tail: What's The Advantage?

Tue Apr 03, 2007 6:24 am

Quoting Pilotaydin (Reply 3):
if you're talking about the extra fin extention on the tail, that is for stability about the vertical axis.....if the aircraft yaws over to one side, the fin helps with moment to recenter the track and direction of the a/c....

if you're talking about the tail skid, that's a different story

One may combine the two  Smile


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SEPilot
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RE: Shape Of 737 Tail: What's The Advantage?

Tue Apr 03, 2007 10:10 am

Quoting ZANL188 (Reply 2):
I think what you're talking about though is the leading edge fairing of the vertical stabilizer where the stabilizer attachs to the fuselage - yes? I

Boeing has a history of putting too small vertical stabilizers on airplanes. If you recall pictures of early B-17's the tail was quite small, and later models (E, F, & G) had a much larger tail (also referred to as a dorsal fin.) This may have come about after the first 307 (which was the airliner developed from the B-17) crashed due to an inadequate vertical stabilizer. The dorsal fin that was added to the 307 was then added to the B-17 as well. The 707 also had to have its tail enlarged; I believe it was just made taller.
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HAWK21M
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RE: Shape Of 737 Tail: What's The Advantage?

Tue Apr 03, 2007 11:23 pm

Quoting Pilotaydin (Reply 3):
if you're talking about the extra fin extention on the tail, that is for stability about the vertical axis.....if the aircraft yaws over to one side, the fin helps with moment to recenter the track and direction of the a/c....

Also called the Dorsal fin.A seperate Attachment longer on the -300 to -900ERs compared to the -100/200s.

regds
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