gm@trsvax (12/27/85)
Hi there. I have a question for you knowledgeable types out there on
commercial aircraft. Of the currently flying (subsonic) airliners, which
one has the highest power-to-weight ratio? I have flown in Boeing 7*7's,
DC-{9,10}'s, a Lockheed L-1011, and an Airbus A300. I have noticed they all
will accelerate at different rates, and seem to climb at different angles.
Subjectively, the fastest accelerator seemed to be a Boeing 737 with
Rolls-Royce something or other engines.
Is there really a big difference, or is it just my all-too-overactive
imagination? What is the Concorde like? What is the shuttle like? :-)
------------
George Moore (gm@trsvax.UUCP)ark@alice.UucP (Andrew Koenig) (12/28/85)
> Hi there. I have a question for you knowledgeable types out there on > commercial aircraft. Of the currently flying (subsonic) airliners, which > one has the highest power-to-weight ratio? I have flown in Boeing 7*7's, > DC-{9,10}'s, a Lockheed L-1011, and an Airbus A300. I have noticed they all > will accelerate at different rates, and seem to climb at different angles. > Subjectively, the fastest accelerator seemed to be a Boeing 737 with > Rolls-Royce something or other engines. A commercial airliner must be able to lose an engine at the worst possible moment during the takeoff roll and still make it off the ground with specified obstacle clearance limits. Thus, the fewer the engines, the more reserve power there must be. A 747 with one engine out is running on 3/4 power; a 737 is running only on 1/2.
cfiaime@ihnp3.UUCP (J. Williams) (12/30/85)
In article <59200011@trsvax> gm@trsvax writes: > > >Of the currently flying (subsonic) airliners, which >one has the highest power-to-weight ratio? ... >Subjectively, the fastest accelerator seemed to be a Boeing 737 with >Rolls-Royce something or other engines. Your twin engine airliners must, by regulation, have a much better power to weight ratio than the three or four engine airliners. FAR Part 25 (large aircraft certification) specifies a positive rate of climb with one engine out. On a twin, you have to climb on 50% power, while on a four engine airplane, you can use 75% power. What it all boils down to is that twin engine FAR 25 airplanes are quite good in takeoff and climb. The 737 has always had good performance. In later versions, such as the 300 series, performance has been greatly improved. 100 and 200 series airplanes use the Pratt&Whitney JT8D engine, while the 300 series uses the SNEMCA CFM56-5. Look for new variants of the airplane in the next few years. jeff williams ihnp3!cfiaime AT&T Bell Laboratories
chad@anasazi.UUCP (Chad R. Larson) (12/31/85)
In article <59200011@trsvax> gm@trsvax writes: > >...Of the currently flying (subsonic) airliners, which one has >the highest power-to-weight ratio?... > There are standards in the FAA's certification procedures that specify minimum performance characteristics for aircraft in degraded configurations. One of those configurations is with an inoperative engine. This means, for example, that a four-engined plane needs to have much less power reserve than a two-engined plane (since the engine-out configuration for a two-engined plane is single-engined). From this you can see the twin engine type planes will be built with good power-to-weight ratios (as you noted about the 737's). This doesn't always translate into take-off acceleration, however. Most airlines now use take-off power computations to determine the minimum power setting for any given field/temperature/wind combination, under the assumption that lower power settings save fuel, wear and noise. Percevied acceleration by the passenger is more often a function of the above parameters than the power-to-weight. For what it's worth, I've known captains with enough seniority to fly any route they wanted who flew 737's instead of 747's/DC-8's. They said the 737 is more like a sports car when compared to the bigger planes. More power reserve, better roll rate, etc. Also, they get used on short hauls which means more take-offs & landings (the fun part). The Concorde is, of course, a different deal. It has massive power to be able to overcome the drag associated with super-sonic flight. It also uses that power (afterburners, even!) to get to the high lift-off speeds its delta wing requires within normal runway lengths. It *does* have strong acceleration. -crl Generic disclaimer goes here...
djmolny@cuae2.UUCP (DJ Molny) (01/01/86)
In article <207@ihnp3.UUCP> cfiaime@ihnp3.UUCP (45261-J. Williams) writes: >The 737 has always had good performance. In later versions, such as the >300 series, performance has been greatly improved. 100 and 200 series >airplanes use the Pratt&Whitney JT8D engine, while the 300 series uses >the SNEMCA CFM56-5. Look for new variants of the airplane in the next >few years. > > jeff williams > ihnp3!cfiaime > AT&T Bell Laboratories While I was hanging around Salt Lake City this morning, I spotted a Western Airlines 737 with turbofan engines mounted under the wings on pylons. They looked similar to the new turbofans on 757's and 767's, only smaller. I didn't see a manufacturer's label, but they looked a lot like GE's. Does anyone know if this is a factory-new 737 (seems unlikely), or a retrofit? I know the old P&W's are noisy gas hogs, while the 737 airframe is a real workhorse, making it a good candidate for a retrofit. -- Regards, DJ Molny ihnp4!cuae2!djmolny
brent@poseidon.UUCP (Brent P. Callaghan) (01/02/86)
Last year I spent a couple of days watching a friend of
mine at his work. He is an air traffic controller at
Prestwick in Scotland.
We were in a good position to observe the climb rates of
various commercial jets on the radar data tag for each
aircraft.
The clear winner was the Boeing 757. I think the 737
was next best.
Sorry, I can't recall what the actual rate of climb was.
He had a liking for fast climbing aircraft,
the less time an aircraft is changing it's altitude - the
easier it is for him.
From my own experience, the 737 seems to give the
steepest deck angle.
--
Made in New Zealand --> Brent Callaghan
AT&T Information Systems, Lincroft, NJ
{ihnp4|mtuxo|pegasus}!poseidon!brent
(201) 576-3475cfiaime@ihnp3.UUCP (J. Williams) (01/02/86)
In article <1724@cuae2.UUCP> djmolny@cuae2.UUCP (-DJ Molny) writes: > >While I was hanging around Salt Lake City this morning, I spotted a Western >Airlines 737 with turbofan engines mounted under the wings on pylons. They >looked similar to the new turbofans on 757's and 767's, only smaller. >I didn't see a manufacturer's label, but they looked a lot like GE's. > >Does anyone know if this is a factory-new 737 (seems unlikely), or a retrofit? >I know the old P&W's are noisy gas hogs, while the 737 airframe is a real >workhorse, making it a good candidate for a retrofit. >-- That is the 737-300, one of the best selling of the new airliners. It has been in service for just about a year. Boeing has a backlog of almost 150 orders for this airplane. (Item of interest: most of the 737 is built in Wichita and shipped to Renton, Washington for final assembly. This is because it is cheaper to pay freight than the taxes on a finished airplane in Segewick County, Kansas...) jeff williams ihnp3!cfiaime
john@gcc-milo.ARPA (John Allred) (01/03/86)
In article <1724@cuae2.UUCP> djmolny@cuae2.UUCP (-DJ Molny) writes: > >While I was hanging around Salt Lake City this morning, I spotted a Western >Airlines 737 with turbofan engines mounted under the wings on pylons. They >looked similar to the new turbofans on 757's and 767's, only smaller. >I didn't see a manufacturer's label, but they looked a lot like GE's. > >Does anyone know if this is a factory-new 737 (seems unlikely), or a retrofit? >I know the old P&W's are noisy gas hogs, while the 737 airframe is a real >workhorse, making it a good candidate for a retrofit. What you saw was a 737-300, a relatively new aircraft. They come with turbo- fans. -- John Allred General Computer Company uucp: seismo!harvard!gcc-milo!john
jeffw@ISM780.UUCP (01/06/86)
/* Written 9:57 pm Dec 26, 1985 by gm@trsvax in ISM780:net.aviation */
/* ---------- "Commercial aircraft power-to-weight" ---------- */
Hi there. I have a question for you knowledgeable types out there on
commercial aircraft. Of the currently flying (subsonic) airliners, which
one has the highest power-to-weight ratio? I have flown in Boeing 7*7's,
DC-{9,10}'s, a Lockheed L-1011, and an Airbus A300. I have noticed they all
will accelerate at different rates, and seem to climb at different angles.
Subjectively, the fastest accelerator seemed to be a Boeing 737 with
Rolls-Royce something or other engines.
Is there really a big difference, or is it just my all-too-overactive
imagination? What is the Concorde like? What is the shuttle like? :-)
------------
George Moore (gm@trsvax.UUCP)
/* End of text from ISM780:net.aviation */
I don't know about the power to weight ratio, but the BAe146 has
the steepest climb angle of any airliner I've ever been in (which
includes 727s, 737s, 747s, DC-[9,10]s, and L-1011s). Since I
don't have the specs on the BAe146 I'll just have to say that it
appears to be a little smaller than the 737 (in both size and
passenger/payload capacity). It has a high-wing configuration
(initial thought when I first saw the craft was that it looked
sort of like an oversized Harrier) with two AVCO Lycoming jet
engines mounted on pylons under each wing. Based on the routes
I've travelled in the BAe146 (with PSA) and its observed
passenger/payload capacity, I'd guess that this airplane will be
used only on the shorter commuter flights.
In addition to the angle of climb, I've noted three other
interesting characteristics of the BAe146 - of the 3 flights I've
taken in BAe146's, all began with with very quick, short takeoff
rolls (the kind that press you into your seat) and all ended with
very steep final approaches (with the craft being in a very
"nose-down" attitude) and short rollouts. These characteristics
must have been contributing factors in PSA's decision to purchase
the BAe146 since it flies into such places as Burbank Airport and
Orange County (John Wayne) International where the take-off and
landing patterns cross over some fairly densely populated areas.
I'd have to think the BAe146 affords the communities below a
litte more peace and quiet than do the other aircraft I've been
in.
If anyone out there has the 'real' specs on this airplane I'd
like to see them. I found it a joy to fly in and am looking
forward to my next commute to S.F.
Jeff Wise
decvax!cca!ima!ism780!jeffwnotes@ucf-cs.UUCP (01/12/86)
The concorde has a power to weight ratio of .5. Actually it is a thrust to weight ratio, its weight is close to that of a DC-8 or a boeing 707 by has twice their thrust per engine.