707 question

the400kid

the400kid

Pre-takeoff checklist
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I read somewhere recently that a 707 often required as much as 8000 ft for takeoff. Was that due to it being underpowered or an inefficient wing?
 
the400kid said:
I read somewhere recently that a 707 often required as much as 8000 ft for takeoff. Was that due to it being underpowered or an inefficient wing?
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Early jets engines didn't have a lot of power, so the aircraft used a lot of runway, particularly if they were heavy on a hot day.
 
Definitely the engines. At MTOGW they ate up more than 8,000 ft.
 
Henning said:
Good God it's hard to believe they haven't re-engined those yet to something more efficient.
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Oh, they have, those were the original KC-135 A model. The tanker full of fuel had to heft A LOT more weight than a typical 707. For a lot of take-offs, the KC-135 As would have a very low initial level off, just to build to the book climb speed.
 
TulsaWeather said:
Oh, they have, those were the original KC-135 A model. The tanker full of fuel had to heft A LOT more weight than a typical 707. For a lot of take-offs, the KC-135 As would have a very low initial level off, just to build to the book climb speed.
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I was talking about the B-52
 
i was a loadmaster on the c135 and flew on both the a model and the b model. on the A when they hit the water injection,the whole plane shook and the noise was unbearable.
 
It's all a matter of how loaded they are.

You want to see something take a lot of runway. Be around a IAD when the transpacific nonstops depart (usually about mid-day). Those 747SPs use just about every inch of runway and they can't take any tailwind.
 
flyingron said:
It's all a matter of how loaded they are.

You want to see something take a lot of runway. Be around a IAD when the transpacific nonstops depart (usually about mid-day). Those 747SPs use just about every inch of runway and they can't take any tailwind.
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There's only a handfull of the SP's left, none in airline service. NASA has one, and a few VIP ships.
 
I used to ride 135's from Eielson to Grissom on a hop to visit at home in OH. Eielson had more than 15,000 ft of runway and I have seen tankers use most of that. As already stated they would pop off the ground and fly low and slow till they build enough airspeed to adequately climb.

When power was first applied it seems to take for ever to start rolling and I would usually time the take off runs. When it his about 1:40 the pucker factor would increase.

Urban legend has it that Hursey Gate was named after an SP that was killed when a 135 didn't make it into the air. The gate was pretty much off the north end of the runway.
 
RotorAndWing said:
There's only a handfull of the SP's left, none in airline service. NASA has one, and a few VIP ships.
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I think Iran Air still flies one. The Bahraini, Qatari, and Saudi Arabian government ones look pretty slick.
 
tmyers said:
I used to ride 135's from Eielson to Grissom on a hop to visit at home in OH. Eielson had more than 15,000 ft of runway and I have seen tankers use most of that. As already stated they would pop off the ground and fly low and slow till they build enough airspeed to adequately climb.
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An ex-airplane partner of mine was a boom operator on KC-135's and later, KC-10's. He said they never practiced at the weights they were loaded to for SAC alert duty.

Their dark joke was that in the event of an alert launch, the first airplane would crash in a huge fireball in the trees at the end of the runway and the rest of the airplanes would use the thermal to get out of ground effect.
 
The -400's aren't any better than the SPs either.
 
flyingron said:
It's all a matter of how loaded they are.

You want to see something take a lot of runway. Be around a IAD when the transpacific nonstops depart (usually about mid-day). Those 747SPs use just about every inch of runway and they can't take any tailwind.
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My dad was a 747 pilot with Pan Am and I recall him saying that the SP climbed like a bat out of hell. I understood that it was powered like a regular 747 but shorter and lighter. Of course, if you loaded it with lead it might have trouble taking off!
 
Warrior said:
My dad was a 747 pilot with Pan Am and I recall him saying that the SP climbed like a bat out of hell. I understood that it was powered like a regular 747 but shorter and lighter. Of course, if you loaded it with lead it might have trouble taking off!
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Yeah, the SP was designed for short island runways in the pacific.:dunno:
 
flyingron said:
The -400's aren't any better than the SPs either.
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The SP's were "Special Performance" - much shorter than the 100's. In fact they only had 4 doors as opposed to 5.

b747spua.jpg
 
RotorAndWing said:
No, it was designed as a longer range version of the -100.
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Well, there's 2 ways to do that, make it smaller with the same fuel or make it heavier with more fuel. The long range routes are the Pacific Routes, and they didn't want to have to refuel at the islands in the middle of the So Pacific. Since the runways were short and the load on those routes not so great, they chose the lower cost option.
 
Henning said:
Well, there's 2 ways to do that, make it smaller with the same fuel or make it heavier with more fuel. The long range routes are the Pacific Routes, and they didn't want to have to refuel at the islands in the middle of the So Pacific. Since the runways were short and the load on those routes not so great, they chose the lower cost
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B747SP

The Boeing 747SP is a modified version of the Boeing 747 jet airliner which was designed for ultra-long-range flights. The SP stands for "Special Performance". Compared with its predecessor, the 747-100, the 747SP retains its wide-body, four-engine layout, along with its double-deck design, but has a shortened fuselage, larger tailplane, and simplified trailing edge flaps. The weight saved by the shortened fuselage permits longer range and increased speed relative to other 747 configurations.[2]

Known during development as the short-body 747SB, the 747SP was designed to meet a 1973 joint request from Pan American World Airways and Iran Air, who were looking for a high-capacity airliner with sufficient range to cover Pan Am's New York–Middle Eastern routes and Iran Air's planned Tehran–New York route. The aircraft also was intended to provide Boeing with a mid-size wide-body airliner to compete with existing trijet airliners.
 
RotorAndWing said:
B747SP

The Boeing 747SP is a modified version of the Boeing 747 jet airliner which was designed for ultra-long-range flights. The SP stands for "Special Performance". Compared with its predecessor, the 747-100, the 747SP retains its wide-body, four-engine layout, along with its double-deck design, but has a shortened fuselage, larger tailplane, and simplified trailing edge flaps. The weight saved by the shortened fuselage permits longer range and increased speed relative to other 747 configurations.[2]

Known during development as the short-body 747SB, the 747SP was designed to meet a 1973 joint request from Pan American World Airways and Iran Air, who were looking for a high-capacity airliner with sufficient range to cover Pan Am's New York–Middle Eastern routes and Iran Air's planned Tehran–New York route. The aircraft also was intended to provide Boeing with a mid-size wide-body airliner to compete with existing trijet airliners.
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The SPs had the same MTOW and the same engines as the -100. When loaded to the gills, it should have the same climb performance.

However, having fewer seats meant that more of that MTOW could be fuel in an SP than in a -100, hence the longer range.

The SP is about 35 feet shorter than a -100, and a -400 as well (they have the same length, though the -400 has a longer upper deck). It's more than 50 feet shorter than a -8. Seeing them side by side makes the SP look like a toy. And Boeing shared our hangar for some of the -8 flight tests.

SPs were obsoleted by the -200, which could manage an SP range with -100 seating, due to more powerful engines.

While I don't have much to compare it to, SOFIA's takeoff rolls are very long, and the 12000 feet at Palmdale look fairly short from the jumpseat. Most of SOFIA's flights take off heavy for 8+ hours at cruise altitude (FL350-450).
 
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SP not made obsolete by -200. Braniff bought SPs well after the -200 came out. I was there working at Braniff at the time. SPs we had definetly did not use -100 engine.
SP had superior range, but sacrificed in pax/cargo capability.
If I want a Wikipedia answer I can look up the bull**** too.
KC -135s have been re engined with CFM56 engines (not the guard ones).
 
We had a couple of them at United back in the early 90's that we inherited from Pan Am. We also got two -123's that we called the Lemon Sisters. You could always tell them because they had only 3 windows on the upper deck. I always liked the -200 because it was the last all steam gauge model. There were virtually no electronic displays outside of the seven segment numeric windows on the INS control units. Everything else was purely mechanical with delicate little flags, needles and pointers that made a cacophony of clicking and whirring noises. The Attitude Indicators and HSI's were especially intricate, complex three dimensional instruments that were so much more interesting to look at than a flat LED screen.
 
Paulie said:
SP not made obsolete by -200. Braniff bought SPs well after the -200 came out. I was there working at Braniff at the time. SPs we had definetly did not use -100 engine.
SP had superior range, but sacrificed in pax/cargo capability.
If I want a Wikipedia answer I can look up the bull**** too.
KC -135s have been re engined with CFM56 engines (not the guard ones).
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So, how are the 747-100 JT9D-7As different from the 747SP JT9D-7As?

Both models transitioned to other engines later in the run, but the design and purpose was reflected in the initial Pan Am order.

You can get the details from Boeing. No need to go to Wikipedia or some random worker's memory.
 
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MAKG1 said:
So, how are the 747-100 JT9D-7As different from the 747SP JT9D-7As?

Both models transitioned to other engines later in the run, but the design and purpose was reflected in the initial Pan Am order.

You can get the details from Boeing. No need to go to Wikipedia or some random worker's memory.
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Braniff's SPs had the 7F engines. Better a random airline mechanic that actually worked the SP than a computer geek for info.
To say they were made obsolete by the -200 is just stupid, different missions.
 
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tmyers said:
Urban legend has it that Hursey Gate was named after an SP that was killed when a 135 didn't make it into the air. The gate was pretty much off the north end of the runway.
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I don't know why it would be an Urban Legend and the gate it hit was at the south end. They moved it after that to the north end. I think you can read about it on the Eielson history page.
 
Warrior said:
My dad was a 747 pilot with Pan Am and I recall him saying that the SP climbed like a bat out of hell. I understood that it was powered like a regular 747 but shorter and lighter. Of course, if you loaded it with lead it might have trouble taking off!
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Put enough fuel in it to reach Tokyo from Washington, DC non-stop and it doesn't climb that well. On the transatlantic routes they could leave entire fuel tanks empty.
 
Tim said:
I don't know why it would be an Urban Legend and the gate it hit was at the south end. They moved it after that to the north end. I think you can read about it on the Eielson history page.
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Stated urban legend because I couldn't prove it other than what I had been told when stationed there.
 
flyingron said:
Put enough fuel in it to reach Tokyo from Washington, DC non-stop and it doesn't climb that well. On the transatlantic routes they could leave entire fuel tanks empty.
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I am having a little trouble finding takeoff performance for the 747 SP but I appreciate the feedback. Probably with enough fuel for a 2 hour flight the SP could take off on a relatively short runway.
 
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