Blackbird
Topic Author
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J-73 Spool-Up Time

Sun Dec 31, 2006 5:54 am

How long did it take for the J-73 to go from idle, to take-off power?

If I recall the J-47, which was used on the F-86, and B-47 had a very slow spool up time, on the order of like 20-30 seconds. The B-47 even needed a parachute so they could run their engines at medium power so if they needed to abort, they could simply jettison the chute, and spool up in a reasonable amount of time. I have no idea how the F-86 pulled off landing-approaches with such a sluggish engine, and dogfights must have been a pain in the butt!

Andrea K
 
ebj1248650
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RE: J-73 Spool-Up Time

Mon Jan 01, 2007 10:23 am

Quoting Blackbird (Thread starter):
How long did it take for the J-73 to go from idle, to take-off power?

If I recall the J-47, which was used on the F-86, and B-47 had a very slow spool up time, on the order of like 20-30 seconds. The B-47 even needed a parachute so they could run their engines at medium power so if they needed to abort, they could simply jettison the chute, and spool up in a reasonable amount of time. I have no idea how the F-86 pulled off landing-approaches with such a sluggish engine, and dogfights must have been a pain in the butt!

Andrea K

While doing research for the F-86H book I wrote, I found several comments made by pilots having to do with aircraft handing characteristics with slatted and non-slatted wing leading edges, but don't recall reading anything about engine spool up time being a problem with the airplane. Mind you, these were guys who were used to flying F-86Fs and earlier Korean War vintage airplanes so it might be they just took slow spool up characteristics in stride and didn't feel it worth mentioning.
Dare to dream; dream big!
 
Blackbird
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RE: J-73 Spool-Up Time

Sat Jan 06, 2007 5:00 am

Fascinating isn't it though?

I wonder if they just operated at high RPM most of the time in dogfights to keep the engine rev-up time down?
 
ebj1248650
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RE: J-73 Spool-Up Time

Sun Jan 07, 2007 9:19 am

Quoting Blackbird (Thread starter):
How long did it take for the J-73 to go from idle, to take-off power?

If I recall the J-47, which was used on the F-86, and B-47 had a very slow spool up time, on the order of like 20-30 seconds. The B-47 even needed a parachute so they could run their engines at medium power so if they needed to abort, they could simply jettison the chute, and spool up in a reasonable amount of time. I have no idea how the F-86 pulled off landing-approaches with such a sluggish engine, and dogfights must have been a pain in the butt!

Andrea K

I forwarded your question to retired Major General Fred Ascani, who commanded the 50th Fighter Bomber Wing, while equipped with F-86Hs, in Europe. Waiting for his reply.
Dare to dream; dream big!
 
Blackbird
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RE: J-73 Spool-Up Time

Sun Jan 07, 2007 12:15 pm

Wasn't Ascani there when the first XB-70 was rolled out?
 
ebj1248650
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RE: J-73 Spool-Up Time

Tue Jan 09, 2007 3:31 pm

Quoting Blackbird (Reply 4):

As I recall, he was in charge of the XB-70 project or at least had a major role in it. He replied to my e-mail and said the J73 had a rapid spool up rate, and that early engines in P-80s and T-33s had slow spool up times. J47 spool up time was something like 20 seconds but in the B-47 that was time well spent as there were so many engine instruments to watch during the spool up.

You'll remember that the B-47 was a tough bird to handle during take off if you lost either outboard engine.
Dare to dream; dream big!
 
Starglider
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RE: J-73 Spool-Up Time

Tue Jan 09, 2007 9:26 pm

Quoting Blackbird (Reply 4):
Wasn't Ascani there when the first XB-70 was rolled out?

He became System Program Director for the XB-70. He was responsible for the acquisition and development of the two aircraft. Funny reading this as i just finished watching his speech on video during the roll-out of AV-1 back in May 1964.

Starglider
 
ebj1248650
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RE: J-73 Spool-Up Time

Wed Jan 10, 2007 6:51 am

Quoting Starglider (Reply 6):
He became System Program Director for the XB-70. He was responsible for the acquisition and development of the two aircraft. Funny reading this as i just finished watching his speech on video during the roll-out of AV-1 back in May 1964.

Starglider

Thanks for the clarification. He is quite a gentleman and has accomplished a lot in his aviation career. Personally, I don't think he gets as much credit as he deserves, broadly speaking.
Dare to dream; dream big!
 
Starglider
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RE: J-73 Spool-Up Time

Wed Jan 10, 2007 10:22 am

Quoting EBJ1248650 (Reply 7):
Thanks for the clarification. He is quite a gentleman and has accomplished a lot in his aviation career. Personally, I don't think he gets as much credit as he deserves, broadly speaking.

I agree, he has done a lot for the development of aviation, WW2 veteran, as a test pilot testing over 50 different types of research and prototype aircraft for which he was awarded, as i remember reading about it a few years ago. The list goes on and on . . . .
 
Starglider
Posts: 657
Joined: Sun Oct 01, 2006 12:19 am

RE: J-73 Spool-Up Time

Mon Jan 15, 2007 3:08 am

Quoting EBJ1248650 (Reply 3):
I forwarded your question to retired Major General Fred Ascani, who commanded the 50th Fighter Bomber Wing, while equipped with F-86Hs, in Europe. Waiting for his reply.

EBJ1248650, reading this, i have an off topic question/request:
In the tech/ops forum i started a thread a while ago regarding a detail of the XB-70, AV-2 (the second prototype). My question is about the function of an external duct or fairing at the right wing root of the second prototype (in that thread i also included a picture for detail). The duct or fairing starts at the right wing root where the wing joins the lower fuselage/engine nacelle, above the right wheel bay and faires back into the lower fuselage near the boat tail. Until now the question remains unanswered. If anyone knows the answer, Major General Ascani would know. Would it be possible to relay this question to him?

Thanks,
Starglider

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