B767 vs B737

[Brajiv]

I'm just wondering why a B767 has got a shorter TODR than a B737. Anyone......?:O

[Capt. J]

May I please add to the question? What is TODR? Thanks

[Brajiv]

Sorry, i meant T/O roll

[Capt. J]

It depends on where it's going. The 767 generally has more power than a 737. If the 767 fills up with full fuel, then it'd be heavier and take up more runway. If it's a short distant flight, it will use less fuel therefore lighter and use less runway but still have as much power which is more than the 737.

The 737 is lighter than the 767 but the 767 has more power than the 737. Again I say, depends on how much fuel is put on the aircraft.

[Capt Fathom]

The 767 generally has more power than a 737
the 767 has more power than the 737
Well, which one is it Capt.J
Does the 767 have more power than the 737 or not.
The 737 is lighter than the 767 but the 767 has more power than the 737. Again I say, depends on how much fuel is put on the aircraft.
Please explain what this statement means..?

[eagerbeaver]

Take off distance required = TODR, and if i remember correctly it is to the screen height of 30ft.

Captain J - do you mean that a 73 has a better thrust to weight ratio at MAUW? or do you think that a 733 with 22k rated engines has more thrust than a 762?
(i dont fly the 767 so have not a clue on its potential thrust available.

because i think the 767 will whip up the 737 every time.

[Crótalo]

Brajiv,

I believe the answer lies in the simple difference of wing design.

To put it very simply (while acknowledging the numerous variables including flap setting, weight, engine de-rate, etc.), the wing on the 737 often requires a greater speed to fly, and it therefore often takes a longer distance to achieve that speed.

Just remember that the above-mentioned variables play a huge part.

[mutt]

Brajiv,

why a B767 has got a shorter TODR than a B737

The short answer is that it doenst!!! You can get a B737-700 off a 5200 ft runway at MTOW while the B767-200 would need 6000 ft.

However the answer isnt as simple as that due to the variation of available engine thrust ratings and restricted takeoff weights. Have a look at these documents and you can judge the differences.

http://www.boeing.com/assocproducts/aircompat/acaps/7672sec3.pdf
http://www.boeing.com/assocproducts/aircompat/acaps/7371sec3.pdf
http://www.boeing.com/assocproducts/aircompat/acaps/7373sec3.pdf
http://www.boeing.com/assocproducts/aircompat/acaps/737wsec3.pdf

Capt J, I thought that TODR was a universal term, did they teach you something else for the Australian Performance "A" exams?


Mutt.

[Brajiv]

Thanks Mutt,
but i believe that they've been a lot of modification. I'm at an airport where there's a lot of 73/76's t/o and both types of a/c seems to lift off around the same area of rwy even though the B737 starts its t/o roll 500-600m longer. I've only seen the 737- 700 & 800 series. i cant make any comment on the 400 series.
Crotalo's answer seems to be right.....better check....:ok:

Cheers

[mutt]

Brajiv,

Its impossible for a lay person to compare two aircraft taking off and come to a conclusion about their abilities. :)
All you can do is deal with the facts that Mr Boeing gives you and then educate yourself about derated engines, assumed temperature takeoffs, improved climb, flap selection and finally takeoff weights.
As an airline, we strive to reduce the takeoff power so much that the aircraft will use all of the runway regardless of takeoff weight!

Mutt. :)

[slice]

It has been mentioned in other forums that the 700/800 series of the 73 family has faily 'ordinary' field performance in that at MTOW it requires a greater TODR than the 300/400/500 series - of course the MTOWs are greater but with a wing that is not a great deal larger and also possibly a lower power/weight ratio (?) TODR is going to increase.


Any 73 drivers to confirm (or deny) ?

[mutt]

Just dealing with facts, based on ISA conditions, FAR takeoff requirements and the highest thrust available for each engine type, the required runway length requirements are:

-300 (63,270 kgs) = 7200 ft.
-400 (68,040 kgs) = 8300 ft.
-500 (60,550 kgs) = 8100 ft.
-700 (70,080 kgs) = 5200 ft.
-800 (79,016 kgs) = 6800 ft.
-900 (79,016 kgs) = 7300 ft.

Guess that its fair to say that the NG is the better performer :)

Please remember that we live in a world of derated thrust, we are planning to use ALL or at least most of the runway!

Mutt. :)

[Bringelly]

Capt. J,

Best wishes for your thirteenth birthday. Good luck with High School when you start!

B

[Cap 56]

Hello Mutt,

You are right, but the figures that you state relay on the brakes as well as engines and wing.

Another interesting angle would be to compare the climb limit weight for the first certified T/O flap setting under ISA and ISA + 15. This would compare the aircraft based on wing and engines only.

Any numbers ?

[mbga9pgf]

TODR=Take Off distance required, for CAA performance group A is from brakes off including initial climb to a screen height of 35 feet

[Cap 56]

and the second segment starts just after that

......to be exact ..just from gear up..... completely independant from the runway...what are you trying to proof

[mutt]

Cap 56, i believe that he was stating that the TORA went to 35 feet rather than the 30 feet stated by a previous poster! I dont feel like compounding his confusion by stating tha the screen height is only 15 feet in certain cases......:)

As for you original question, considering that they are all twin engine aircraft, so the climb limit for the NG aircraft are going to show higher weights! I think that what you are looking for may lie in the ALL engine accelerate go distance shown in the community noise document. Unfortunately i dont have access to that document for the 737 fleet.


Cheers

Mutt.

[swh]

mutt,

I have been told there was little change made to the brakes on the 737NG vs the 737OG, with a new wing, requireing higher V speeds, and higher weights, what did Boeing do to reduce the distances ?

I know of an airport that had its runway extended to cater for the 737NG, where the 737OG and A320's operated to previously.

Do different ICAO states have different requirments for selecting the TODR, ADSA etc ?

Do the winglets (if installed) on a 737NG have any effect on TODR apart from increasing the operating/basic weight of the aircraft ?

:confused:

[Cap 56]

Mutt,

Indeed you are right, the comparison btw 737 and 767 using the WAT or second segment would be contaminated by the drag of the engine that is at idle or shut down.

All engines perfo on t/o go is a better way to compare the real perfo.

Thanks, interesting and stimulating discussion

[mutt]

swh,

Hang a smaller engine on the -700 and the 5200 ft turns into 8000 ft.

As for the winglets, check out http://www.aviationpartnersboeing.com

Mutt.