Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Stupid 777 Fact That Is Bugging Me!  
User currently offlineBoston92 From United States of America, joined Aug 2006, 3390 posts, RR: 7
Posted (7 years 3 months 3 days 15 hours ago) and read 4027 times:

Why is the 777-200 one inch taller (tail height) than the 777-300?

[Edited 2007-07-01 03:09:46]


"Why does a slight tax increase cost you $200 and a substantial tax cut save you 30 cents?"
23 replies: All unread, jump to last
 
User currently offlineGo3Team From United States of America, joined Mar 2004, 3267 posts, RR: 16
Reply 1, posted (7 years 3 months 3 days 14 hours ago) and read 4016 times:

I think it's because shorter planes need taller tails, although one inch probably doesnt make much difference. Could be, they have the same gear, and the inch difference is due to the weight.


Yay Pudding!
User currently offlineLehpron From United States of America, joined Jul 2001, 7028 posts, RR: 21
Reply 2, posted (7 years 3 months 3 days 13 hours ago) and read 3967 times:

Quoting Boston92 (Thread starter):
Why is the 777-200 one inch taller (tail height) than the 777-300?

I grow an inch every time I sleep and loose it throughout the day.  Wink



The meaning of life is curiosity; we were put on this planet to explore opportunities.
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17054 posts, RR: 67
Reply 3, posted (7 years 3 months 3 days 13 hours ago) and read 3945 times:

Quoting Go3Team (Reply 1):
I think it's because shorter planes need taller tails, although one inch probably doesnt make much difference. Could be, they have the same gear, and the inch difference is due to the weight.

Both good theories.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineViscount724 From Switzerland, joined Oct 2006, 25450 posts, RR: 22
Reply 4, posted (7 years 3 months 3 days 13 hours ago) and read 3945 times:

I stand to be corrected but I'm almost certain the the tails themselves are the same height on all 777s but the overall height from the ground to the top of the tail probably varies slightly due to the different overall lengths and weights etc. I believe the landing gear is also somewhat different on the -300ER vs. the standard -200 and -300.

User currently offlineRoseFlyer From United States of America, joined Feb 2004, 9661 posts, RR: 52
Reply 5, posted (7 years 3 months 3 days 9 hours ago) and read 3832 times:

I would assume it has something to do with the modifications done to the landing gear for the 777-300. 1 inch isn't that much, but could be accommodated with a different gear.


If you have never designed an airplane part before, let the real designers do the work!
User currently offlineA342 From Germany, joined Jul 2005, 4683 posts, RR: 3
Reply 6, posted (7 years 3 months 3 days 7 hours ago) and read 3789 times:

I also think it has got to do with the landing gear. Maybe the 777 has a (very small) "negative AOA" on the ground. As the nose gear length is the same, the shorter fuselage of the 772 makes the tail stand up higher than on the 773.


Exceptions confirm the rule.
User currently offlineOzTech From Australia, joined Feb 2007, 161 posts, RR: 0
Reply 7, posted (7 years 3 months 3 days 3 hours ago) and read 3703 times:

Just a thought but it might have something to do with the tyre size.. Ply ratings etc. I know the different versions of most Boeings have different ply ratings and diameters etc.


No defect too big, no defect too small, nothing in the log --- No defect at all !!
User currently offlineKFLLCFII From United States of America, joined Sep 2004, 3303 posts, RR: 30
Reply 8, posted (7 years 3 months 2 days 23 hours ago) and read 3571 times:

Why is the tail taller on the 747SP compared to the regular 747 models?

Why is the tail taller on the 736 compared to other 737 models?

Why is the tail taller on the A318 compared to other A32X models?


Because shorter (length-wise) aircraft, in order to get the same amount of lateral performance out of the rudder for engine-out operations, need a larger surface area on the tail to account for the decreased distance of the moment "arm" about the CG.  Wink

And yes, that extra "inch" of additional height can make all the difference in the world with regard to Vmc (minimum-controllable airspeed with an engine out).



"About the only way to look at it, just a pity you are not POTUS KFLLCFII, seems as if we would all be better off."
User currently offlineOldAeroGuy From United States of America, joined Dec 2004, 3527 posts, RR: 67
Reply 9, posted (7 years 3 months 2 days 22 hours ago) and read 3535 times:

Quoting KFLLCFII (Reply 8):
Because shorter (length-wise) aircraft, in order to get the same amount of lateral performance out of the rudder for engine-out operations, need a larger surface area on the tail to account for the decreased distance of the moment "arm" about the CG.

And yes, that extra "inch" of additional height can make all the difference in the world with regard to Vmc (minimum-controllable airspeed with an engine out).

Good thinking, but there is no difference in vertical tail sizes between the -200 and -300 models.

Quoting A342 (Reply 6):
I also think it has got to do with the landing gear. Maybe the 777 has a (very small) "negative AOA" on the ground. As the nose gear length is the same, the shorter fuselage of the 772 makes the tail stand up higher than on the 773

You're on the right track, but the concept is wrong. A negative attitude on the ground would mean the longer body airplane would have the tip of the vertical higher off the ground.

Quoting Go3Team (Reply 1):
Could be, they have the same gear, and the inch difference is due to the weight.

Actually it's the weight and the gear. The documents below give a range for the distance between the tip of the vertical tail and the ground. This distance varies as a function of airplane weight, CG position, and gear strut charge pressure.

Model Min Dist Max Dist

-200 60' 5" 61' 6"
-300 60' 5" 61' 6"
-200LR 60' 8" 61' 6"
-300ER 59' 10" 61'10"

http://www.boeing.com/commercial/airports/acaps/777rsec2.pdf

http://www.boeing.com/commercial/airports/acaps/777rsec2.pdf



Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
User currently offlineBrettbrett21 From United Kingdom, joined Jun 2004, 436 posts, RR: 0
Reply 10, posted (7 years 3 months 2 days 21 hours ago) and read 3482 times:

I have another questionable fact. I dunno where I heard this and I'm pretty sure that it's wrong.

Is the horizontal stabilizer of the 777 roughly the same size as the 737's wings?



i'm so excited i wish i could wet my pants!
User currently offlineBoston92 From United States of America, joined Aug 2006, 3390 posts, RR: 7
Reply 11, posted (7 years 3 months 2 days 21 hours ago) and read 3475 times:

Quoting Brettbrett21 (Reply 10):
I have another questionable fact. I dunno where I heard this and I'm pretty sure that it's wrong.

Is the horizontal stabilizer of the 777 roughly the same size as the 737's wings?

The 777 Horizontal Stabilizer is 66 feet wide, the wingspan of the 737 is 112 feet, so yeah, the 777 HS is larger than a 737 wing.



"Why does a slight tax increase cost you $200 and a substantial tax cut save you 30 cents?"
User currently offlineViscount724 From Switzerland, joined Oct 2006, 25450 posts, RR: 22
Reply 12, posted (7 years 3 months 2 days 18 hours ago) and read 3398 times:

Quoting OldAeroGuy (Reply 9):
Quoting KFLLCFII (Reply 8):
Because shorter (length-wise) aircraft, in order to get the same amount of lateral performance out of the rudder for engine-out operations, need a larger surface area on the tail to account for the decreased distance of the moment "arm" about the CG.

And yes, that extra "inch" of additional height can make all the difference in the world with regard to Vmc (minimum-controllable airspeed with an engine out).

Good thinking, but there is no difference in vertical tail sizes between the -200 and -300 models.

Assuming you're referring to the 747, the -200 and -300 are the same length.


User currently offlineLegoguy From United Kingdom, joined Jun 2006, 3313 posts, RR: 39
Reply 13, posted (7 years 3 months 2 days 16 hours ago) and read 3346 times:

Quoting Brettbrett21 (Reply 10):
I have another questionable fact. I dunno where I heard this and I'm pretty sure that it's wrong.

Is the horizontal stabilizer of the 777 roughly the same size as the 737's wings?

Slightly off topic but I thought the fact was more along the lines of the A380 horizontal stabilizer is the same size as a 737's wing.



Can you say 'Beer Can' without sounding like a Jamaican saying 'Bacon'?
User currently offlineJetMech From Australia, joined Mar 2006, 2699 posts, RR: 53
Reply 14, posted (7 years 3 months 2 days 13 hours ago) and read 3233 times:

Quoting Boston92 (Thread starter):

Could be the extra sag in the longer fuselage  Wink !

Regards, JetMech



JetMech split the back of his pants. He can feel the wind in his hair.
User currently offlineSEPilot From United States of America, joined Dec 2006, 6924 posts, RR: 46
Reply 15, posted (7 years 3 months 2 days 4 hours ago) and read 3071 times:

Quoting OldAeroGuy (Reply 9):
You're on the right track, but the concept is wrong. A negative attitude on the ground would mean the longer body airplane would have the tip of the vertical higher off the ground.

Actually, both of you are wrong. If the landing gear are both the same length and the ratio of the length from main gear to nose gear and main gear to tail is the same, the tail height will be exactly the same regardless of length, although the angle will be different. If the ratio changes the height will also change, which may account for the difference.



The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
User currently offlineOldAeroGuy From United States of America, joined Dec 2004, 3527 posts, RR: 67
Reply 16, posted (7 years 3 months 2 days ago) and read 2979 times:

Quoting SEPilot (Reply 15):
Actually, both of you are wrong. If the landing gear are both the same length and the ratio of the length from main gear to nose gear and main gear to tail is the same, the tail height will be exactly the same regardless of length,

Who said all the ratios are the same?



Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
User currently offlineSEPilot From United States of America, joined Dec 2006, 6924 posts, RR: 46
Reply 17, posted (12 years 4 months 3 weeks 5 days 5 hours ago) and read 2978 times:

Quoting OldAeroGuy (Reply 16):
Who said all the ratios are the same?

I didn't; in fact I said that if they weren't that could account for the difference.



The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
User currently offlineBoston92 From United States of America, joined Aug 2006, 3390 posts, RR: 7
Reply 18, posted (7 years 3 months 1 day 23 hours ago) and read 2978 times:

Quoting SEPilot (Reply 17):
I didn't; in fact I said that if they weren't that could account for the difference.



Quoting SEPilot (Reply 17):
5 years 1 month 3 weeks 3 days 5 hours ago

I started the thread yesterday, a.net is broken...



"Why does a slight tax increase cost you $200 and a substantial tax cut save you 30 cents?"
User currently offlineSEPilot From United States of America, joined Dec 2006, 6924 posts, RR: 46
Reply 19, posted (7 years 3 months 1 day 21 hours ago) and read 2950 times:

Quoting Boston92 (Reply 18):
I started the thread yesterday, a.net is broken...

Are you sure? Perhaps you took a quick unwitting trip in your time machine....



The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
User currently offlineBrettbrett21 From United Kingdom, joined Jun 2004, 436 posts, RR: 0
Reply 20, posted (7 years 3 months 1 day 4 hours ago) and read 2769 times:

Quoting Boston92 (Reply 11):
Quoting Brettbrett21 (Reply 10):
I have another questionable fact. I dunno where I heard this and I'm pretty sure that it's wrong.

Is the horizontal stabilizer of the 777 roughly the same size as the 737's wings?

The 777 Horizontal Stabilizer is 66 feet wide, the wingspan of the 737 is 112 feet, so yeah, the 777 HS is larger than a 737 wing.

I actually *gasp* looked it up after I asked, man do I feel dumb!



i'm so excited i wish i could wet my pants!
User currently offlineA342 From Germany, joined Jul 2005, 4683 posts, RR: 3
Reply 21, posted (7 years 3 months 1 day 4 hours ago) and read 2761 times:

Quoting OldAeroGuy (Reply 9):
You're on the right track, but the concept is wrong. A negative attitude on the ground would mean the longer body airplane would have the tip of the vertical higher off the ground.

Yes, but because the forward fuselage is also longer (on the 773), the negative attitude should be reduced, shouldn't it?



Exceptions confirm the rule.
User currently offlineOldAeroGuy From United States of America, joined Dec 2004, 3527 posts, RR: 67
Reply 22, posted (7 years 3 months 1 day 2 hours ago) and read 2727 times:

Quoting A342 (Reply 21):
Yes, but because the forward fuselage is also longer (on the 773), the negative attitude should be reduced, shouldn't it?

As noted earlier, the change in tail height depends on the ratio between forward and aft body stretches. Note that there is no difference between 772 and 773 vertical tail ranges in Reply 21.

Quoting OldAeroGuy (Reply 9):


Model Min Dist Max Dist

-200 60' 5" 61' 6"
-300 60' 5" 61' 6"
-200LR 60' 8" 61' 6"
-300ER 59' 10" 61'10"



Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
User currently offlineInnocuousFox From United States of America, joined Dec 2003, 2805 posts, RR: 14
Reply 23, posted (7 years 3 months 1 day 2 hours ago) and read 2703 times:

I like the 777 fact that you can fit a 737 or MD-80 fuselage inside a 777 engine.  Smile


Dave Mark - Intrinsic Algorithm - Reducing the world to mathematical equations!
Top Of Page
Forum Index

Reply To This Topic Stupid 777 Fact That Is Bugging Me!
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
Am 777 - Is That A Rat? posted Fri Dec 1 2006 00:12:55 by LawnDart
That Passenger Has Flu And Is Sitting Next To Me posted Sat Nov 5 2005 20:03:37 by Julesmusician
Is That Highly Impossible For Me?.... Please ... posted Mon Jan 22 2001 14:41:02 by Jack-747
Where Is The Crew Rest Area In A 777? posted Sat Mar 31 2007 06:02:59 by Jawed
Things That Make Me Go Hmmm....on A320 No:2 posted Fri Feb 2 2007 10:01:44 by Wing
Is Being A CSA That Difficult? My Story posted Mon Jan 8 2007 22:20:41 by KLM672
Things That Make Me Go Hýmm....on A320 No:1 posted Tue Jan 2 2007 18:30:46 by Wing
Is That A Hummer? posted Wed Dec 14 2005 17:15:11 by Nirmalmakadia
What Is That Red Window? posted Fri Nov 4 2005 18:10:22 by PipoA380
Is That A "tail Collapse"? posted Sun Aug 21 2005 12:43:28 by Pihero

Sponsor Message:
Printer friendly format