Airliner Power to Weight Ratios

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So, for you airline/military pilots -

I'm an A&P, and, as I'm driving back and forth on the ramp at BNA, looking at all the different airliners (Embraer ERJ 145s, 170s, 190s, CRJs, MD-80s, Airbus A320s, 757s, MD-10s, the occasional Atlas 747-400, Air Force One, etc, being a guy who likes fast cars and bikes, and airplanes, I'm always wondering which ones are the "hotrods".

I've heard that the 757 has the best power to weight ratio with either the RR or the PW engines - can't remember which. Also read that the 727 was always considered a real "pilot's airplane", as far as airliners go. And I know the 747 has the most extreme wing sweepback angle of any airliner, and has been described as a joy to fly, despite its size.

So, to those of you who are/were airline pilots, or, otherwise, have flown some of these types, which ones are considered the "hotrods"? Which ones did you particularly enjoy flying?

Another question - I've always wondered how large aircraft with high-wing configuration (C-141, C-5, C-17, etc.) handle, compared with the more common low-wing designs. They look like they'd be slower, and not handle as well, but, usually, when I've looked up specs, the speeds don't seem much slower. Also, do they handle as well? Why were none of these ever bought by airlines and used as passenger airliners (well, there's the old Avro RJ, and maybe a couple of others, I guess)? I also remember reading that Lockheed tried to sell a version of the C-5 as a large jumbo pax airliner.
 
I'd love to see a takeoff thrust to weight chart of the various airliners. It's my understanding that the 757 was king in this regard.

Something of note, some engine designs perform better at altitude than others. So a T/O thrust to weight chart won't necessarily reflect real world high altitude performance. Furthermore, aircraft with a low drag profile and lower wing loading can often outclimb aircraft with smaller high speed wings at higher altitudes.

Also, long range aircraft carry a lot of fuel, which obviously adds a massive amount of weight. Those same aircraft may be fantastic
and efficient performers on shorter trips. The Gulfstream G650ER comes to mind. It's a very clean airframe, but when it's fueled for 7500 nautical miles, about 43% of it's 104,000 pound MGTOW is fuel! Most G650ER trips carry no more than 1/2 fuel, and East cost trips may be only 1/4 tank, leading to thrilling performance.
 
Originally Posted by Cujet
I'd love to see a takeoff thrust to weight chart of the various airliners. It's my understanding that the 757 was king in this regard.

Something of note, some engine designs perform better at altitude than others. So a T/O thrust to weight chart won't necessarily reflect real world high altitude performance. Furthermore, aircraft with a low drag profile and lower wing loading can often outclimb aircraft with smaller high speed wings at higher altitudes.

Also, long range aircraft carry a lot of fuel, which obviously adds a massive amount of weight. Those same aircraft may be fantastic
and efficient performers on shorter trips. The Gulfstream G650ER comes to mind. It's a very clean airframe, but when it's fueled for 7500 nautical miles, about 43% of it's 104,000 pound MGTOW is fuel! Most G650ER trips carry no more than 1/2 fuel, and East cost trips may be only 1/4 tank, leading to thrilling performance.



Man, those are all really good points!
 
My reply is all second hand knowledge from speaking with pilots that flew them.

Out of the ones you listed, Air Force One has the most juice. The Air Force guy that flew it didn't give any numbers but said it's "a great performer".

In stock trim, the 757 is the best climbing aircraft.

The 727 is among the fastest but eats a lot of fuel. Drug runners used to buy old ones to outrun the DEA's Citation jets - then leave them on the runway after unloading.
 
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Didn't concorde regularly achieve 5000FPM?

I sat next to a 757 pilot once on a flight and he told me that on a run to deliver it for maintenance empty and light fuel load they had the thing vertical fo longer than he thought possible - he said it was really impressive.


UD
 
Yeah there are some airplanes that are pretty neat. I've never gotten into plane performance, partly because I'm not a pilot but mainly because most planes these days are never on time because of other problems at airports.
smile.gif


Back around 2000, after the SR-71s were all retired, my grandpa started telling us stories about what he had done in the late 50s and 60s. He had worked for Moog for most of those two decades, and had been part of the top-secret project to get the SR-71 into the sky as he was part of the hydraulics team. He had worked with Kelly Johnson directly during the project. One of the most amazing things to me was he said they had to develop special hydraulic fluids and fittings because as the plane got going so fast, the air friction over the airframe actually caused the shell to expand, so panels and other things moved significantly as they expanded. Things got so hot that when there was a hydraulic rupture and the fluid came into contact with air, it could/would spontaneously combust. Kinda scary thinking about the combination of losing your flight surface controls AND catching on fire at the same time, while flying 2000+ MPH over enemy territory! As history has shown, the group of engineers overcame the challenge and ended up with an incredible machine that destroyed the boundaries of what most people had previously thought possible. I really miss my grandpa.
 
Originally Posted by SubieRubyRoo
my grandpa started telling us stories about what he had done in the late 50s and 60s. He had worked for Moog for most of those two decades,


We are currently installing Moog hydraulic components in the F-35 Lightning II in Fort Worth.

He would be proud to know that.
 
Originally Posted by JLTD

The 727 is among the fastest but eats a lot of fuel. Drug runners used to buy old ones to outrun the DEA's Citation jets -.


My uncle started in the airlines in the early 80's on the 727 as an FE.

Mach .95 wasn't any problem in a 727... but, YES - very thirsty airplane.
 
Awesome Linc! Slightly different missions and scales of speed, but neat nonetheless. My favorite jet from my Navy days was the F14, not the 18... the 'Cat just exuded muscle and sheer power, yet with quite a bit of finesse as well.

Thanks for the news, I think you'd be right.
 
Originally Posted by john_pifer
Originally Posted by Cujet
I'd love to see a takeoff thrust to weight chart of the various airliners. It's my understanding that the 757 was king in this regard.

Something of note, some engine designs perform better at altitude than others. So a T/O thrust to weight chart won't necessarily reflect real world high altitude performance. Furthermore, aircraft with a low drag profile and lower wing loading can often outclimb aircraft with smaller high speed wings at higher altitudes.

Also, long range aircraft carry a lot of fuel, which obviously adds a massive amount of weight. Those same aircraft may be fantastic
and efficient performers on shorter trips. The Gulfstream G650ER comes to mind. It's a very clean airframe, but when it's fueled for 7500 nautical miles, about 43% of it's 104,000 pound MGTOW is fuel! Most G650ER trips carry no more than 1/2 fuel, and East cost trips may be only 1/4 tank, leading to thrilling performance.



Man, those are all really good points!


On my last job I ran a line maintenance station for Airborne Express. We ran DC-9's thru my station and UPS used 757's. We both departed ICT at just about the same time and arrived at SGF. We could take off up to 10 minutes after them and still beat them to SGF with plenty time for approach/land. Our pilots loved the DC-9's especially the -30 or -40 series that had the JT-8D-17R engines. All the pilots referred to it as the "sports car" of the air because of how it flew. The 57 could definately out climb and was really impressive at max blow, but we could whip the snot out of them with the little 9's on top end. BTW, when I worked for TWA, all the 727 drivers referred to them as Miss Piggy. I asked one of the pilots why and he told me it was because they just didn't like to climb much over 32,000 ft. He said they just liked to "wollow around" like a pig getting above that especially in the summer. They also took a lot of runway at max gross on a hot day too.
 
So much depends on the gross weight at the time you're measuring performance, and thrust/weight isn't the only thing that gives you climb rate, wing efficiency and drag matter, too.

The fuel fraction of many airliners is about 30%, some are higher. Passengers/payload can be up to 20%.

So, light on fuel, no passengers, and you've got a jet that weighs half of what it normally does. I've ferried an empty 757. It's impressive.

But so was a 747-400 with "only" 100,000# of fuel. It grossed about 300,000# less than usual, between the light fuel and less than full passenger load. It climbed like a Hornet (less AB).

For airliners in general, the 757 is a hot rod. Great power. Especially with RB-211s

Some biz jets have outstanding climb rate. The Gulf Stream line and other high altitude performers have a lot of excess thrust down low...
 
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Originally Posted by Astro14

Some biz jets have outstanding climb rate. The Gulf Stream line and other high altitude performers have a lot of excess thrust down low...


It's not unusual for a classic GIV (medium bypass RR Tay engines w/o FADEC) to make well more than the indicated maximum of 10,000 FPM climb on a cool day and still be accelerating smartly at 40 degrees pitch up. But at 40,000 feet, climb rate is leisurely. The GIII with it's low bypass RR Spey engines actually outperform the Tay at alt and pilots that transitioned from the GIII to the GIV often complained about the lack of high altitude climb rate.

The current G650ER has excess thrust at any altitude up to about FL450 and more than enough at FL510. Not unusual to see a lightly loaded G650ER to make 4000FPM at 40,000 feet.


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I once knew a retired Eastern pilot. He said his favorite plane to fly was the 707. Described as driving a large luxury sedan. He also liked the 757 for its power. He said one 757 engine had more thrust than all three engines combined on a 727. Also, he felt the 727 was one of the best constructed air craft he flew.
 
Good thread. Glad you revived it, @billt460

I’ve posted it before, but it deserves to be in this thread - An absolutely astounding clip of an (obviously lightly-loaded) AF KC-10 Extender running up to a very high takeoff speed (probably close to maximum tire speed, I’d guess), and then converting that excess speed into a near-vertical climb, which I didn’t know was possible to do in a widebody, trijet!

Take a look at the comments section within YouTube - It seems that several folks who were a part of that air wing have commented.

KC-10 Extender Insane Vertical Takeoff:

 
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