Climb performance

Operating an F-16 on the ground or in the air - from the engine start sequence, over replacing a wing, to aerial refueling procedures
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DocZ

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Unread post08 Feb 2006, 02:24

What would be the best power setting for the best fuel efficient climb for a typically loaded AG mission?

Thanks
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Taco44

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Unread post08 Feb 2006, 02:35

Depends on where you are. In a combat zone, MAX AB with MAX climb to get the hell away from the bad guys. If you're not being shot at, I would guess it would depend on MGTOW and loadout.
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Destro

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Unread post08 Feb 2006, 02:40

There are two varibles you can set the power for (3 if you throw in an engine failure). You can set the power to get to the top of climb in the least amount of time or you can set the power to cover the least amount of ground in the climb. Which would you rather do?
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DocZ

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Unread post08 Feb 2006, 02:41

I'm asking about initial climb to cruise with typical load. I would presume that would put you about a thousand under Max.
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DocZ

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Unread post08 Feb 2006, 02:48

I need the most fuel efficient rate, which is Vy (I think).
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Destro

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Unread post08 Feb 2006, 02:53

Are you trying to go as far as you can on one bag of gas, or do you just want to get to the top of climb as soon as possible?
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DocZ

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Unread post08 Feb 2006, 02:54

Get to TOC with the least amount of fuel used.
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Destro

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Unread post08 Feb 2006, 02:57

Vy = Best rate of climb (unit of time)
Vx= Best angle of climb (unit of horzontal distance)
Best Glide= least amount of altitude lost for the maximum amount of horizontal distance covered
L/D Max= point on the drag curve where parasite and induced drag are at a minimum
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DocZ

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Unread post08 Feb 2006, 02:59

Thanks, Destro. I know the definitions, what I want is the power setting and IAS.
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hansundfranz

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Unread post08 Feb 2006, 11:53

You asked the same question over at frugals in regard to the sim?

I guess yes. Anyway for F4 you got your answer, Use those numbers. precise RL numbers (if you can get them) wonßt help at all. After all you´re flying not a real F16.

Overall I don´t think that military (fighter) aviation is as sophisticated as civilian comercial flying when it comes to fuel effiency. The priority is not in saveing money but on getting the job done so I doubt there is more then fairly simple rules of thumb which profiles must be flown for best fuel efficiency,

The lastest generation (F22, EF, Grippen) might have or might get something that resembles the functions of a civilian FMS (although I haven´t heard of it),
Where is that switch in the cockpit? If that is not OPSEC of course
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Raptor_One

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Unread post08 Feb 2006, 18:16

There are optimum climb schedules for the F-16 which depend on power setting (MIL or AB), type of F-16 (block/variant), and drag index. In all cases though, you maintain a specific indicated airspeed (KIAS) until reaching a specified Mach number after which you maintain that Mach number. For an F-16C Block 25 you would have the following:

MIL Power
------------
Drag Index (DI) = 0:
450 KIAS until Mach 0.88

DI = 300:
300 KIAS until Mach 0.72

Max AB
---------
DI = 0:
575 KIAS until Mach 0.90

DI = 300:
500 KIAS until Mach 0.85


There's more data than what I just listed, but I don't feel like copying it all down here. Anyway... for newer blocks with better performing engines, the speeds may be slightly higher in some cases. Drag index and throttle position are the factors that most affect the climb speeds. The lower your drag index, the faster your climb speeds. The more thrust you're putting out, the faster your climb speeds. The manual doesn't list any other power settings besides MIL and AB and chances are you wouldn't save much fuel by climbing at, say, min AB vs. max AB or a lower RPM than MIL power.
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hansundfranz

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Unread post08 Feb 2006, 19:28

These numbers are for best climb speed measured in feet/second not for the most fuel efficient climb / flight profile and also not for the best total energy gain profile (potential energy = altitude and kinetic energy = speed changes).
Nevertherless interesting and thanks for digging them up.

BTW do you still consider doing H-M Constant 1g diagrams for your F4 flightmodells?
Where is that switch in the cockpit? If that is not OPSEC of course
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DocZ

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Unread post08 Feb 2006, 22:00

I ddn't ask a question about this on Frugal's, although I did read the thread. I found it interesting and wondered if there was a power setting to achieve best ecoomy in the climb. It has nothing to do with the sim. But thanks for all the gueses. If someone really knows an answer, I'd still like to hear it.

And, in this day and age, fuel economy on training flights has become very important. The number of monthly training hours has been reduced, mostly for economic reasons. The days of kick the tire and light the fires are long gone.
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Destro

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Unread post08 Feb 2006, 22:22

Doc-
I'm not trying to be a smart a-- about this at all but there are alot of varibles that go into your question. Altimeter setting, temperature, drag index, fuel load, and more. I would say that the numbers Raptorman gave would be better than ballpark. They look like they came outta a block 25 dash 1. I know for a fact that transport category aircraft (airliners) with an FMS calculate a climb speed for you and dispay it on the PFD so you can fly it. They don't even talk Vx, or Vy in that community. The airbus for example uses "green dot" to represent the best combination of Vx, and Vy, and displays it as a green dot on the airspeed tape. This changes every time you enter new numbers for the above mentioned variables into the FMS. The Viper has sort of FMS although thats not what its called it does the same thing. Every flight the numer is gonna change. Maybe one of the drivers or the pointy heads could answer this better. I'm not positive, but I doubt there is a standard number that you use for a climb speed though.
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DocZ

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Unread post08 Feb 2006, 22:42

Destro--

I know you aren't trying to be smart-a** about this nor is anyone else. I am a RW pilot and understand that the you can use an FMS or pencil and paper to calulate climb speeds for best fuel burn in any airplane. I presume that those in charge of paying for the gas in training missions and those trying to task combat aircraft at least try to be as economical as possible. I would appreciate it if one of the drivers or someone with actual experience chimed in here.

Raptorman's numbers for the sim are just that, a simulation. If he runs out of gas, he punches the ESC button and starts over.
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