EconoBoy
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757 Over Powered?

Wed Feb 02, 2005 4:27 am

I saw an aviation TV program recently in the which the presenter, who is also a 757 First Officer, expressed the opinion that the 757 is the most over powered airliner in the sky. If this is so, why the excess power? Was it due to commonality requirements with the 767? And does it make the 757 a fun plane to fly, or lead to problems if you are unfamiliar with it?
Incidentally, the presenter is also lead singer with a heavy metal band: what a life some people have!
 
SlamClick
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RE: 757 Over Powered?

Wed Feb 02, 2005 4:32 am

As an old F-106 pilot said in ground school:

"The only time an airplane is overpowered is if you are going straight up at flight idle and it pulls the wings off."


I found the 757 to be powerful but not mind-bogglingly so.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
SATL382G
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RE: 757 Over Powered?

Wed Feb 02, 2005 4:48 am

Twins tend to have somewhat more power, compared to tri & quad jets, in order to allow for the engine out case on takeoff.
"There’s nothing quite as exhilarating as being shot at and missed" --Winston Churchill
 
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BALandorLivery
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RE: 757 Over Powered?

Wed Feb 02, 2005 7:01 am

Friend of mine flies the 757 for Astraeus and he I asked him about it because I have heard this before too.

His answer: yes.

The 757 is overpowered, theres a lot more thrust than is required especially so with the RB211-535-E4 engine.

Regds.
 
744lover
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RE: 757 Over Powered?

Wed Feb 02, 2005 8:07 am

Hi there,


I had the chance to fly a RG 757 (PP-VTS) on its "test flight" on GIG.

We rolled out of VEM (Varig Engineering and Maintenance) hangar and headed to RW28. Just to feel the power, the pilot selected full thrust for takeoff and I can just say: WOOOW. I felt pasted to the seat and we reached FL120 in under 3 minutes.

It's a great plane and a shame that Boeing quit its producion.



See ya,
GHN
 
AAR90
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RE: 757 Over Powered?

Wed Feb 02, 2005 8:12 am

"Overpowered" is a relative term. AA's 757s are "overpowered" for most North American flights, but are hardly "overpowered" for South American flights...especially the "high altitude" airports. Certainly as used by AA, the MD90 was considerably more "overpowered" than AA's 757.


*NO CARRIER* -- A Naval Aviator's worst nightmare!
 
KYIPpilot
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RE: 757 Over Powered?

Wed Feb 02, 2005 8:38 am

IIRC, there were problems with tailstrikes when the 757 first came out, because it really "leaped" off the runway on takeoff.

Also, I heard that the 757 is the only airliner that can climb to altitude with its initial takeoff pitch up attitude. So yes, It has a lot of power to spare.
"It starts when you're always afraid; You step out of line, the man come and take you away" -Buffalo Springfield
 
flyf15
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RE: 757 Over Powered?

Wed Feb 02, 2005 9:29 am

The CRJ, MD-90, and 717 all have higher thrust/weight ratios than the 757 if I remember correctly. There may be some others aswell...
 
SlamClick
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RE: 757 Over Powered?

Wed Feb 02, 2005 9:38 am

Subjectively I thought the DC-9-15 outperformed it in climb. The only real test, though is to get actual numbers.

Thrust - Weight - Wing Area
compare those between the 757 and some others.

Frankly I'd be surprised if it compared favorably to a 737NG.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
Yikes!
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RE: 757 Over Powered?

Wed Feb 02, 2005 10:47 am

The 757 (with RB211 535E4 engines) is not overpowered. The 757=200 variants have GTOW's ranging from 104 K kg to 114 k kg. At the lighter non-ETOPS weights, it PERFORMS. At the heavier weights, you don't want to lose an engine, especially at high density altitudes.

Tail strikes are a non-issue as they are largely a product of technique.
 
air2gxs
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RE: 757 Over Powered?

Wed Feb 02, 2005 11:10 am

I was jumpseating once on a B757PF and we did a go-around from abour 10 feet RA (runway incursion). In my humble opinion, any full aircraft that can do a GA from 10ft, and never touch the ground, has a whole lot of power.
 
777wt
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RE: 757 Over Powered?

Wed Feb 02, 2005 1:04 pm

I was told which was said from a pilot, with the flaps down 5 or 20 deg and one engine to full thrust, the 757 would flip itself over.
 
3201
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RE: 757 Over Powered?

Wed Feb 02, 2005 1:37 pm

The problem with comparing thrust-to-weight ratios is you have to know what weight to use. This is really a continuation of AAR90's thoughts. If you use the MTOW, the question is how often is a 757 at or near MTOW compared to other aircraft. From what I've seen, it's hard to get a 757 anywhere near its MTOW on a short/medium flight. So basing a T/W comparison on MTOW vs. basing it on what you're likely to see day-in/day-out for each aircraft type will give different answers. I have no way of measuring how often 757 is near MTOW compared to other aircraft, but I'd guess it's a lot less frequent.

It's probably not over-powered at all if you're a UK charter airline stuffing way too many people in flying anywhere further than LEXX, or CO flying it trans-Atlantic, or anyone flying it west coast to Hawaii... but for ATL-RSW in a two-class layout, that's another story.

BTW, it's my all-time favorite aircraft, so by no means am I bashing it.  Innocent
7 hours aint long-haul
 
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HAWK21M
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RE: 757 Over Powered?

Wed Feb 02, 2005 8:16 pm

What about the B752PF,That would be really loaded considering its cargo.
Im keen on knowing about it,cause we may be going in for Two in First Quarter 2006.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
schooner
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RE: 757 Over Powered?

Wed Feb 02, 2005 9:15 pm

Dunno about over-powered because its the only airliner I have flown so have nothing to compare it to but........makes performance planning out of poxy Greek airfields fairly easy, no need to worry about off-loading bags or stuff like that, you just go!

Cheers.

PS,last ferry flight, FL410 in 17 minutes using all the derates!
Untouched and Alive
 
schooner
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RE: 757 Over Powered?

Wed Feb 02, 2005 9:17 pm

Oh and 777WT, I think it would if you left the autopilot in  Sad.
Untouched and Alive
 
AAR90
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RE: 757 Over Powered?

Thu Feb 03, 2005 4:44 am

I was told which was said from a pilot, with the flaps down 5 or 20 deg and one engine to full thrust, the 757 would flip itself over.

Not a chance. Someone's pulling your leg.
*NO CARRIER* -- A Naval Aviator's worst nightmare!
 
SlamClick
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RE: 757 Over Powered?

Thu Feb 03, 2005 5:13 am

"I was told which was said from a pilot, with the flaps down 5 or 20 deg and one engine to full thrust, the 757 would flip itself over."

I'm with AAR90 on this one to some extent. In the first place if true it has more to say about the adequacy of the rudder than about the power. This is a VMC issue.

So, my notes say that the speed limit at flaps 20 is 195 knots. If your weight is such that your VMC was higher than that I'd have to agree.

The wonderful thing about VMC is that it is only at that value at full power. So reduce power. Too bad more light twin pilots never understood that.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
2H4
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RE: 757 Over Powered?

Thu Feb 03, 2005 5:15 am

If you want to talk about impressive thrust to weight ratios, have a look at corporate jets.

For example, if you examine power loading (MTOW divided by total rated thrust), the Cessna Citation Encore comes in at 2.45.


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That's better than the G550, BBJ, ACJ, etc. In fact, even the F-104 and F-4 carry around about 1.80 pounds of weight for every pound of thrust at MTOW.


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Depending on engine choice, the 757 comes in at about 2.93. There are many variables I haven't gotten into, but the general comparisons remain about the same. In the end, bizjet performance is quite impressive.


2H4


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MD-90
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RE: 757 Over Powered?

Fri Feb 04, 2005 8:58 am

So reduce power. Too bad more light twin pilots never understood that.

I guess they don't understand how poorly most light twins fly on just one engine, do they?
 
SlamClick
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RE: 757 Over Powered?

Fri Feb 04, 2005 9:27 am

Right.

I'd rather crash a symmetrical glider than land a light twin on its windshield.

Happiness is not seeing another trite Ste. Maarten photo all week long.
 
N808NW
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RE: 757 Over Powered?

Fri Feb 04, 2005 1:17 pm

If its so over powered then why do the 757's on the trans atlantic routes only make it to FL280?

-Jason
All flights have great IFE...get yourself a window seat, thats something no PTV can beat! flew 808 Pacific an Atlanic
 
mconway
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RE: 757 Over Powered?

Fri Feb 04, 2005 7:20 pm

If its so over powered then why do the 757's on the trans atlantic routes only make it to FL280?

I guess I must have dreamed working all those CO's 757's flying in the mid and high thirties on the Atlantic crossing  Smile The only reason a 757 would be limited to F280 on the crossing would be due to a lack of MNPS/RVSM certification.
 
SlamClick
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RE: 757 Over Powered?

Fri Feb 04, 2005 11:55 pm

There is also the factor of wing loading.

On the B-727-200 with -17 engines, the engines would be happy to push the plane up to the thin air where the wings would no longer support it.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
lehpron
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RE: 757 Over Powered?

Sat Feb 05, 2005 12:13 pm

Wouldn't it be better to have extra power, therefore one does not run the engine at full all the time and maybe the engine will last longer in addition to getting out of the airport faster than to bug stupid NIMBY monkeys? DUH!
The meaning of life is curiosity; we were put on this planet to explore opportunities.
 
3201
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RE: 757 Over Powered?

Sat Feb 05, 2005 3:20 pm

> Wouldn't it be better to have extra power,

Bigger (than needed) engines = more drag, more weight, and more $$$ to buy in the first place. You can be overly conservative in aircraft design if you really want to, but there's always a price to pay.
7 hours aint long-haul
 
airbusA346
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RE: 757 Over Powered?

Sat Feb 05, 2005 9:26 pm

They guy you were talking about is in a band called Iron maiden and he flies for Astraeus, but can not think of his name.

Tom
Tom Walker '086' First Officer of a A318/A319 for Air Lambert - Hours Flown: 17 hour 05 minutes (last updated 24/12/05).
 
schooner
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RE: 757 Over Powered?

Sat Feb 05, 2005 10:53 pm

Just to clarify, I wasn`t saying that it would flip itself over regardless......but if the a/p is in (AND you didn`t input any rudder) it would try to oppose the yawing motion with aileron until it couldn`t handle it anymore and then "pop", a/p gives up and you`re on your back!

Cheers.

PS, its Bruce Dickinson.
Untouched and Alive
 
airbusA346
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RE: 757 Over Powered?

Sun Feb 06, 2005 4:32 am

Does any body know when Bruce Dickinson was going to do that program at Boeing.

Tom
Tom Walker '086' First Officer of a A318/A319 for Air Lambert - Hours Flown: 17 hour 05 minutes (last updated 24/12/05).
 
AAR90
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RE: 757 Over Powered?

Sun Feb 06, 2005 12:10 pm

Just to clarify, I wasn`t saying that it would flip itself over regardless......but if the a/p is in (AND you didn`t input any rudder) it would try to oppose the yawing motion with aileron until it couldn`t handle it anymore and then "pop", a/p gives up and you`re on your back!

Still not a chance.
AAR90
AA 757 pilot for 10 years.
*NO CARRIER* -- A Naval Aviator's worst nightmare!
 
SlamClick
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RE: 757 Over Powered?

Sun Feb 06, 2005 12:25 pm

I believe that there is an element of truth in what he says but it would be true for just about any airplane with a thrust asymmetry.

If you flamed one out and did NOTHING about it, but left the autopilot on, and you would deserve what happens next. The autopilot would trim and trim until it hit its limits. If that was not enough, it would disengage. I don't even care what would happen next. Bunch of trim one way, bunch of thrust the other.

(he shudders)


Happiness is not seeing another trite Ste. Maarten photo all week long.
 
2H4
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RE: 757 Over Powered?

Sun Feb 06, 2005 12:30 pm

I've heard P-51s and Spitfires can produce enough torque on takeoff and go-arounds to overcome aileron/rudder authority, if power is applied carelessly.


2H4
Intentionally Left Blank
 
schooner
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RE: 757 Over Powered?

Sun Feb 06, 2005 7:43 pm

Thanks Slamclick. That is what I was trying to get across but I am unfortunately not the most eloquent of people when it comes to technical matters!

Cheers,

Schooner
TCX 757 pilot for less than one year Big grin
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AAR90
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RE: 757 Over Powered?

Mon Feb 07, 2005 7:58 am

I believe that there is an element of truth in what he says but it would be true for just about any airplane with a thrust asymmetry.

The"element of truth" requires multiple system failures at exactly the right moment in time for such a scenario to play itself out --all while the pilots intentionally take absolutely no action. Since the 757 A/P is not certified nor designed to fly in such extremis situations, that is not a very likely scenario.

I've watched AA's 757 simulators fly such a scenario many times (ordered not to touch anything for demonstration purposes) and the A/P does a "decent" job of flying the plane out of a very low, very slow single-engine max-power go-around. Heading control stinks, but it does not lose flight control authority and the plane does not roll inverted... until a pilot touches the controls without being prepared for the control forces to be encountered. You also need very low temps & pressure altitudes (i.e. greater than maximum certified thrust) to create such a scenario.

A human pilot flys much more efficiently (at least all the AA ones I've watched/participated with) in such extremis situations (use of rudder helps a great deal).
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HAWK21M
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RE: 757 Over Powered?

Mon Feb 07, 2005 3:11 pm

Anyone having details on the B757-200PF version & the operators that use these Aircraft.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
schooner
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RE: 757 Over Powered?

Mon Feb 07, 2005 9:27 pm

Sheesh! I never implied that it is the norm for this to happen.... Well, at least I have a request for my next sim check if there is any spare time at the end Big grin !

Cheers.
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