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Adam!
12-01-2007, 07:40 AM
Okay, i'm intrested to find out something - I don't know the answer, and they'll proberbly be different but because I know alot about planes I know that its safe and all that malarki (So do a few other people on this forum, so unfortinataly you can't take part).

On takeoff in a Boeing 747 aircraft, do you feel the aircraft is going slow? - I mean, it goes slower than most aircraft, but then with all the extra weight and 2 more engines it's going ot happen.

It's just, it came up in conversation at school a few days ago and people that had been on a 747 said they got scared on takeoff because the plane seemed to be going so slow and very low engine power.

However, I'll say this; 747's are very safe, they have alot of engine power on departure and are going faster than you might expect.

Overdose
12-01-2007, 08:13 AM
a 747 is just as same as a normal plane but bigger, you'd have to be a propper geek to notice that it was going slower.

I mean your not exactly gonna go..

"OMG THIS 747 GOES SLOWER THAN A NORMAL PLANE BECAUSE IT IS BIGGER"

etc.

But you are a propper geek so, yeah you never know.

:Hazel
12-01-2007, 10:02 AM
But you are a propper geek so, yeah you never know.

Bit harsh lol.

I wouldn't know notice the difference in speed I don't think tbh.

lSander
12-01-2007, 01:08 PM
I noticed nothing.
I tought same as allways, and I don't care about how fast does it take off, It's just how fast you get there, & do you get there safe.
and 747's are super safe :).

Kenneth
13-01-2007, 09:27 PM
The 747 TRust per
63,300 lbf PW
62,100 lbf GE
59,500 lbf RR
x 4
compared to
GE-90 of
777
Thrust Range: 74,000-115,000 lbs.
x 2
so its almost the same but the size of the 747 is big so it seems wierd also V1 is usally 141 and VR is 145 and V2 175 so its fast

Adam!
13-01-2007, 09:35 PM
I don't know much about 747, lol..

However, 141 for V1 is just about the same for any aircraft, give or take 10/20 knots.

V2 175 is fast.

What I don't get is, can you stop a 747 at 145 at VR if you decide to abort? - Makes you wonder, you must be able too though.

Kenneth
13-01-2007, 10:10 PM
No V1 is go or no go also know as decide and climb is V2 + 20

Adam!
13-01-2007, 10:15 PM
By the time you've said ABORT you'd be at VR lol..

Kenneth
13-01-2007, 10:43 PM
You would usally abort before V1 in case of failure but after V1 you have to take anything into the sky.

-Soph-
13-01-2007, 10:44 PM
Yeah when I flew over here to USA the other day on a 747 I found it slow on take off, I always do.. I was also sat right at the back of the plane, and I felt it shaking and swaying from side to side as well.. which was a bit odd

Adam!
13-01-2007, 10:47 PM
You would usally abort before V1 in case of failure but after V1 you have to take anything into the sky.
Errrr, not always ;)

There was a engine fire on an aircraft at EGCC and the pilot goes V1... ABORT!

But yeahhhhh, nobody knows what where talking about so lets shut up lmao!

Luckyrare
13-01-2007, 11:02 PM
Boeing 747 has quite a quick take off speed for its size I would say. Its around 180 mph but it depends on tailwinds, weight, the pilot, run way size and many other factors.
(http://www.aerospaceweb.org/aircraft/jetliner/b737/)

Adam!
13-01-2007, 11:14 PM
Boeing 747 has quite a quick take off speed for its size I would say. Its around 180 mph but it depends on tailwinds, weight, the pilot, run way size and many other factors.
(http://www.aerospaceweb.org/aircraft/jetliner/b737/)
How is it depending on the pilot?

You takeoff into headwind, not with tailwind.. The runway size will be big enough to support a 747 with maximum weight..

Luckyrare
13-01-2007, 11:33 PM
How is it depending on the pilot?

You takeoff into headwind, not with tailwind.. The runway size will be big enough to support a 747 with maximum weight..

Well, the pilot chooses how far he/she taxis onto the runway. The smaller the run way the more throttle you will need. Not a huge factor of course but it would change the speed while on the run way. Some airports have small run ways so they have to really get all the engines going and put it straight onto full throttle. While larger run ways they may choose to build up speed bit by bit until they get up to the take off speed. This wont change the take off speed as such put it will change the speeds while on the run way.

Scrub pilot from my last post tbh :p

cocaine
13-01-2007, 11:35 PM
im afraid of flying full stop.

:[

Adam!
13-01-2007, 11:52 PM
Well, the pilot chooses how far he/she taxis onto the runway. The smaller the run way the more throttle you will need. Not a huge factor of course but it would change the speed while on the run way. Some airports have small run ways so they have to really get all the engines going and put it straight onto full throttle. While larger run ways they may choose to build up speed bit by bit until they get up to the take off speed. This wont change the take off speed as such put it will change the speeds while on the run way.

Scrub pilot from my last post tbh :p
Ummm, your just gonna have to trust me on this one.

A pilot NEVER uses full throttle on takeoff, NEVER! - 3/4 throttle.. Aircraft don't usually go full thottle unless there is an emergency, even then it can only be for about 10 minutes.

No matter how big the runway is, the pilot wants to use the minimum possible!

Also, 80% of the time they are cleared for takeoff at the hold - In which case you taxi onto the runway, line up and depart within 15 seconds of recieving the clearance.

The way I've been personally taught is when cleared for take off at the gate, taxi into the centre and roll without stopping at all. If you don't ATC will start shouting "BLEH BLEH ROLL NOW!!"

On landing, the pilot may lay off the brakes for a little while so they can vacate at a later taxiway rather than having to taxi at about 40 knots, however proberbly only when the pilot is familiar with the airport! :)

Anyway, I sound like a complete geek and I'm going to shut up now.

Kenneth
13-01-2007, 11:55 PM
Well, the pilot chooses how far he/she taxis onto the runway. The smaller the run way the more throttle you will need. Not a huge factor of course but it would change the speed while on the run way. Some airports have small run ways so they have to really get all the engines going and put it straight onto full throttle. While larger run ways they may choose to build up speed bit by bit until they get up to the take off speed. This wont change the take off speed as such put it will change the speeds while on the run way.

Scrub pilot from my last post tbh :p
I am sorry to inform that that is wrong.
To/ga handles that and takeoffs are usally no more than 95 n1. you would almost always takeoff in a 747 with to/ga ( take off/ go around) mode which controlls the speeds programed into the fmc. and you would usally taxi from the end of the runway giving you lots of space and most runways are about atleast 6500 ft where a 747 flies.
Also full throttle will break the ruway like tear it apart also usally less than 90n1

tailwinds
Where have you been?

Luckyrare
14-01-2007, 12:16 AM
I am wrong. sozard <3

Adam!
14-01-2007, 12:18 AM
I am wrong. sozard <3
Thanks for admitting it ;)

Anymore to challange me and Tom? ;)

Kenneth
14-01-2007, 12:18 AM
Also a 747 has a slower takeoff climb rate .
lol @ above post

Rock:Dude
27-01-2007, 09:01 PM
I thought I knew about planes...

obviously not, Although a pilot may decide he wants to give the passengers a flight to remember and go "off roading" in his pimped up 747 Mwhahaha!
Propa British Airway stickers, massive front landing lights, The biz!!

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