Afterburner Takeoffs

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Phil Schuyler

Well-Known Member
I had the privilege to take my little girls to see the Thunderbirds yesterday. One loved it the other not so much. Anyway, watching the takeoff, I got to wondering why fighter jets use afterburner on takeoff when it doesn't seem necessary (runway length, etc). Seems like a waste of fuel and wear and tear. What's the story?
 
Can't speak to the Viper, but in the Hornet, you pretty much need to do AB takeoffs. In 5 years of flying it, I have probably only done a couple mil powered takeoffs, and that was with like 50% fuel, no external stores, to go do field carrier landing practice (FCLP). With a full fuel load and a normal configuration, you will eat up a lot more runway at mil power (I don't have the book in front of me, but I'd venture a guess that it would be another 3-4k feet). So as you can imagine, that would just artificially reduce your margin for error on a takeoff abort. You want to get airborne as quickly as possible and start getting some airspeed on the jet as a general rule of thumb. Then if anything happens, you can deal with it airborne, rather than being in a weird no mans land at 100+ knots, unable to fly, and without enough runway in front of you to safely abort. If that explanation makes any sense.
 
///AMG said:
Can't speak to the Viper, but in the Hornet, you pretty much need to do AB takeoffs. In 5 years of flying it, I have probably only done a couple mil powered takeoffs, and that was with like 50% fuel, no external stores, to go do field carrier landing practice (FCLP). With a full fuel load and a normal configuration, you will eat up a lot more runway at mil power (I don't have the book in front of me, but I'd venture a guess that it would be another 3-4k feet). So as you can imagine, that would just artificially reduce your margin for error on a takeoff abort. You want to get airborne as quickly as possible and start getting some airspeed on the jet as a general rule of thumb. Then if anything happens, you can deal with it airborne, rather than being in a weird no mans land at 100+ knots, unable to fly, and without enough runway in front of you to safely abort. If that explanation makes any sense.
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That makes perfect sense. Thanks for the explanation.
 
AMG, Can you post some cockpit pictures? or send any high quality full bird pictures to me? Like to hang some to hang on my wall maybe
 
Phil Schuyler said:
I got to wondering why fighter jets use afterburner on takeoff when it doesn't seem necessary (runway length, etc). Seems like a waste of fuel and wear and tear. What's the story?
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What makes you think it is not necessary?

I think you might be surprised by the takeoff data numbers. Fighters are heavy, and the faster you can get to takeoff speed, the safer things are in case of emergency.

Only very rarely in the F-15E did we have the pressure altitude necessary to make a MIL-power takeoff (safely), and even then it was only in the PW-229-engined jets, and not the -220 jets.
 
Hacker15e said:
What makes you think it is not necessary?

I think you might be surprised by the takeoff data numbers. Fighters are heavy, and the faster you can get to takeoff speed, the safer things are in case of emergency.

Only very rarely in the F-15E did we have the pressure altitude necessary to make a MIL-power takeoff (safely), and even then it was only in the PW-229-engined jets, and not the -220 jets.
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Granted I know nothing about this, that's why I was asking. I was making the assumption that a 10000+ foot runway was plenty long. I stand corrected.
 
I will also say that on a 7 month cruise, I can count on one hand how many times i didn't go to full AB on the cat, and I can count on zero fingers how many times I wasn't shoving the throttles through the AB stops on the trap. With a normal combat load, you were settling pretty well off the cat which is uncomfortable during the day, and pretty scary at night.
 
Phil Schuyler said:
Granted I know nothing about this, that's why I was asking. I was making the assumption that a 10000+ foot runway was plenty long. I stand corrected.
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Just for some perspective, in the Strike Eagle our minimum allowable runway length is 8,000'.
 
///AMG said:
I will also say that on a 7 month cruise, I can count on one hand how many times i didn't go to full AB on the cat, and I can count on zero fingers how many times I wasn't shoving the throttles through the AB stops on the trap. With a normal combat load, you were settling pretty well off the cat which is uncomfortable during the day, and pretty scary at night.
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Single engine failure on a mil-power cat shot, I don't like the sound of that in anything, especially an F-18.
 
Patrick said:
That sounds decidedly unenjoyable!
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Yeah I would think it would not be......closest I ever had was an afterburner blow out on the cat, which was kind of insidious. I remember thinking "did I bring the gear and flaps up? is my speedbrake out?" Couldn't really climb any faster than about 200 knots. The VEN had failed full open so I was getting a lot less than normal thrust. Also had a weird one that took a while to get figured out. Left motor would not go to mil power up at altitude the first time you pushed it up to mil. You had to slam the throttle back to idle several times, then slam it forward to the mil stop and then it would finally spool above 80% or so. Which ended up being awesome trying to get into the basket of the KC-135 at night. Ended up splitting the throttles about a foot before the probe got into the basket, going min burner on the right, and idle on the left like 2-3 times.....back to mil as i make contact and finally the left spools up and i can come out of blower on the right. I'm sure the boom operator was really wondering what was going on.
 
///AMG said:
Yeah I would think it would not be......closest I ever had was an afterburner blow out on the cat, which was kind of insidious. I remember thinking "did I bring the gear and flaps up? is my speedbrake out?" Couldn't really climb any faster than about 200 knots.
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Did you have yard sale?
 
///AMG said:
Yeah I would think it would not be......closest I ever had was an afterburner blow out on the cat, which was kind of insidious. I remember thinking "did I bring the gear and flaps up? is my speedbrake out?" Couldn't really climb any faster than about 200 knots. The VEN had failed full open so I was getting a lot less than normal thrust. Also had a weird one that took a while to get figured out. Left motor would not go to mil power up at altitude the first time you pushed it up to mil. You had to slam the throttle back to idle several times, then slam it forward to the mil stop and then it would finally spool above 80% or so. Which ended up being awesome trying to get into the basket of the KC-135 at night. Ended up splitting the throttles about a foot before the probe got into the basket, going min burner on the right, and idle on the left like 2-3 times.....back to mil as i make contact and finally the left spools up and i can come out of blower on the right. I'm sure the boom operator was really wondering what was going on.
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Did you ask the tanker to tobaggan?
 
MikeD said:
Did you ask the tanker to tobaggan?
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lol. Those tanker dudes are entertaining. I especially liked the boom operators who would be like "back 2" the instant you got plugged in on the maiden, and then they spar with you on the boom for the next 10 mins. For the love of god, just hold the boom still and let me do my thing. I think they are just used to the AF method......which is really weird to watch BTW especially on the Vipers, I had never seen it until now. I wanted to send the tanker LNO a ppt of what we are trying to do with the jet though.....knuckle on the outboard right motor and hold it there. Try doing that when the boom is fighting you the whole time and the broken old bird doesn't have autopilot on. Some were actually very good though, and knew how to make it real smooth. I will say that I preferred the maiden. The KC-10 was a big fluffy basket that you could plug with your eyes closed, but it flowed somewhere around the rate of the oceana hot pits. MIPR was my least favorite.....those were the closest times I ever had to tearing off an AoA probe or damaging the refuel probe. That and if that take up reel doesn't work and you hammer it home, you have about 1 second to get the hell out of there before your probe gets ripped off and thrown down the right intake. You had to respect the maiden, and the costs of gooning it away were probably more serious, but you could take a 10.0 in like 5-6 minutes.
 
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