delta2477a
F-106 Skilled
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Posts: 101
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Post by delta2477a on Nov 9, 2005 9:23:42 GMT 9
Okay...
The J-79 was said to be the first engine with a modulating afterburner, with 5-different AB settings.
The J-75 had at least Min AB, and Full AB (did it have other settings?)
Which came first?
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Post by Jim on Nov 9, 2005 12:42:24 GMT 9
Okay... The J-79 was said to be the first engine with a modulating afterburner, with 5-different AB settings. The J-75 had at least Min AB, and Full AB (did it have other settings?) Which came first? THE 75 WAS VARIABLE, IN THAT YOU COULD MOVE FROM MIN TO MAX AND STOP AT ANY POINT IN BETWEEN.......THE OPERATOR WAS THE MODULATOR............THE 79 WAS A MULTI STAGE BURNER MANNER OF SELECTION UNKNOWN BY THIS OLD TIMER The Old Sarge |
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Post by John Bartoszewicz on Nov 9, 2005 23:09:08 GMT 9
The J-79 did have a staged AB, but not as you are thinking. The light off was in stages, rather then an explosive kick in the pants. In the 60-61 time frame, the 479th at George AFB would release the brakes and light the fire. It is only that the Airspeed at the yard marker was too slow and the EGT was not right that the pilot knew that the AB did not light up. Now get this, he would abort the takeoff using only his brakes, taxi back around and try it again. Unbelievable! Between 61 and 65, I saw the 479th lose more F-104s than all A/C all the rest of my AF career. In 61, the F-104 also had downward ejection. BUMBER!!! Jack  |
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Post by Jack Bartoszewicz on Nov 10, 2005 1:28:17 GMT 9
Hey Delta keep those questions coming. Different engines from the same manufacturer are built for different purposes at the same time. The J-75 is really a souped up and improved J-57, using a vari ramp panel in the intake to control the flow of air at high speed and altitude. Yes it is possible to choke a jet engine. At high speed even at high altitudes, you can shove too much air down the intakes. The J-79 did not re-lie on a vari ramp. The compressor vanes could change pitch, thus controlling the amount of air passing though the engine, thus the Banshee sound when repositioning the throttle. There was some idea of a Super Interceptor based on the B-58 with 4 J-75s. Wonder how they would have controlled this problem? Back to the J-75, Ref: T.O. 1F-106A-1, Dated 1 Nov 1980, Change2 - 30 April 1985. ENGINE AFTERBURNER SYSTEM Operation of the afterburner is controlled by the throttle. When the throttle is placed outboard to the AFTERBURNER range, the afterburner shut-off valve is opened by power from the dc essential bus. At the same time the afterburner fuel pressure to the exhaust nozzle control pneumatically opens the exhaust nozzles during afterburner operation. When engine thrust is varied, afterburner thrust will also vary. NOTE The afterburner can be used while the engine is operating on the emergency fuel control system if the main system fails. Caution When Operating on the emergency fuel control system, rapid throttle movements must be avoided to prevent overspeed, overtemperature, compressor stalls and flameouts. Got the book ;D , it's a good read after all these years. Peace,  Jack |
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delta2477a
F-106 Skilled
Currently: Offline
Posts: 101
Location:
Joined: August 2005
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Post by delta2477a on Nov 13, 2005 6:45:53 GMT 9
So, for the J-75 the settings were minimum, and ANY setting in between, and max? Or just minimum and Max?
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Post by Jim on Nov 13, 2005 13:09:39 GMT 9
So, for the J-75 the settings were minimum, and ANY setting in between, and max? Or just minimum and Max? Once the burner was lit at minimum (normal for initial test runs following engine maint, etc) the throttle acted just like the volume control on your stereo.. ;D  ;D With this explanation, I believe that you should be able to grasp how the afterburner functioned on the J75,57, 47,48 and a few J-35 engines.......By the way, those last two engines were centrifugal flow engines, used in what a/c?  ?? Now, Delta don"t get me wrong, I look forward to your questions and hope that you have many more, because they bring BLACK BART out of hiding.....But pay attention when in school with BLACK BART, an ye be a gettin a lot of smarts an the forum be somewhat active  the Old Sarge |
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Post by Jack Bartoszewicz on Nov 14, 2005 4:01:18 GMT 9
Delta, Sarge is true as can be and the T.O. is very straight forward. Say on your stereo the balance is locked to center. The left is the afterburner, while the right is the engine throttle setting. Turn the volume from Min to Max. The balance stays constant. Unlock the balance and the left speaker shuts off as slapping the throttle right shuts down the burner. You are just thinking too complicated!  But us MA-1 Weenie did that too! Take Care, Jack  |
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;D
?? Now, Delta don"t get me wrong, I look forward to your questions and hope that you have many more, because they bring BLACK BART out of hiding.....But pay attention when in school with BLACK BART, an ye be a gettin a lot of smarts an the forum be somewhat active 
