Most fuel efficient Speed/Height ?

[Brit_Radar_Dude]

Anyone any info on the Speed and Height to fly for the optimum fuel efficiency in Lockon? A couple of times I have been flying back to land after taking damamge and leaking fuel, one time just made it back, had to glide in as the engines quit - what a blast!

The other occasion, I had to punch out a couple of miles short. Most annoying and made me think about how high/fast I should try to fly in these situations.

 

I use most every flyable in Lockon, so it would be nice to know this info for all of them............

[Gazehound]

The only rules of thumb I know of are that the lower you are the more efficient your engines work, and the slower you fly the less fuel you will use. So I suppose low enough to fly mostly level and slow enough to fly smoothly - although if you are going to run out of fuel your altitude wants to be 2/3 of the distance to the AB or better.

[Pilotasso]

Nope... the most fuel eficient way to travel is between 26000 (to avoid contrail) and 33000 feet. While lower the engine is more efficient but the bigger is the drag.

Increasing to high altitudes the drag decreases much faster than the loss of efficiency, added to the fact that high altitude thin air requires much faster speeds for the same amount of oxygen flow for the burn, and since you wont go any faster than your usual cruise speed- typicaly around mach 0.8-0.9 - it also means you get lower specific consumsumption despite what the loss of engine efficiency might compell you to think.

 

This is why airliners fly at high altitudes and not sea skimming...

[Gazehound]

This is why airliners fly at high altitudes and not sea skimming...

LOL! never thought of that!

[suntrace1]

Air is also cooler, which adds to higher entropy of the burning process. Like intercooler or NOS in a car.

[GGTharos]

Plus, you want to climb as high as you posisbly can (efficient climb) while you have fuel, because you might have to glide back down after yoru fuel runs out, and altitude=range.

 

I've managed to glide the 15 for some 40nm at some point.

 

The most efficient altitude varies with your payload.

 

Firstly, you want to be able to fly high.

 

Secondly, you ant to be able to fly high where you can still actually fly with the engines working at 95% rpm. 90% if you're clean and desperate.

[yamangman]

This is why airliners fly at high altitudes and not sea skimming...

 

 

That's not entirely true. A large aircraft skimming the surface of the water can be up to 60% more fuel efficient, due to the "cushion" of air beneath the aircraft creating lift. But flying at 31000 feet is the most practical way.

[Jester_159th]

Just one thing on this: I've taken minor damage in one wing (flying the 25T) and got a fuel leak. At the time I had about a 65-70% full fuel load. Within a matter of minutes I had a low fuel situation.

 

Surely if hit in one wing, it shouldn't drain my entire fuel load, but only the tank in that wing?

[Bungle_uk]

well, the aircraft may pump fuel from one tank to another to maintain the aircrafts center of gravity. It may be a completley automated procedure. I think most airliners have this capability. Of course I could be completley wrong on this too :)

[SwingKid]

Anyone any info on the Speed and Height to fly for the optimum fuel efficiency in Lockon?

 

Mach 0.8 @ 40,000' gives optimal ~0.5 km/kg fuel for MiG-29.

 

AFAIK there is no "ground effect" in Lock On. :(

 

-SK

[Jester_159th]

well, the aircraft may pump fuel from one tank to another to maintain the aircrafts center of gravity. It may be a completley automated procedure. I think most airliners have this capability. Of course I could be completley wrong on this too :)

 

Very possibly. But I would have thought a manual override would be fitted to an automated cross-feed system.

[SUBS17]

Really need a functioning ICP to calculate optimum cruise altitude and speed since weapons load and fuel state effect this.

[Jay]

Just one thing on this: I've taken minor damage in one wing (flying the 25T) and got a fuel leak. At the time I had about a 65-70% full fuel load. Within a matter of minutes I had a low fuel situation.

 

Surely if hit in one wing, it shouldn't drain my entire fuel load, but only the tank in that wing?

 

 

I think this is a bug and should be fixed, because if your wing tank is damaged, it shouldn't affect the centerline tank. And this one is pretty large compared to the wing's, so it should be possible to land on alternate airbase in this situation without much problem (of course jettison weapons and external fuel tank first, please!)...

[Brit_Radar_Dude]

Thanks. I guess the answer is to climb to gain altitude and hence range as GCTharos said. Which therefore brings on my next question - efficient climb rate?

[GGTharos]

That's a tough one ... and really depends on your fuel state - sometimes you can't afford to climb at all, but I haven't generated any charts so I'm not able to tell you anything specific ...

 

In general, you'll want to be able to maintain approximately mach 0.8 (or less - the important thing is to be able to fly at 90rpms) - pull the nose up until the aircraft isneither speeding up nor slowing down - climb at that angle, and grdually lower the nose as the aircraft begins to slow in order to maintain airspeed. Do this until you're flying straight and level without falling out of the sky.

 

My typical climbout for the F-15 with fuel available is about Mach 0.9-1.0 with the nose as high as it can be without reducing mach (forget airspeed. Mach is the only thing that should matter to you in all this) but in a flameout situation you can't maintain optimal climb attitude, so you'll have to settle for a gentle speed-preserving climb.

 

This should work out the best for you in almost any situation.

[Brit_Radar_Dude]

Fast, informative response from GGTharos - way to go mate! Thanks.....

[Cobra747]

there is an aweful lot of mis-information in this thread.

 

Jet Engines are more efficient at higher altitudes (however they do lose thrust). By efficient i mean they burn less fuel.

 

A typical airliner would fly around the 35,000' mark as it is the most efficient altitude. (your optimum altitude is weight dependant so it changes from flight to flight but that is a very rough average.) If we want speed we fly around 27,000' as that is where you get your best TAS, but we burn a fair bit of fuel doing so and with fuel prices so high you will find most airlines now have a policy regarding Fuel Cost/Schedule. All the other reasons for being up that high are sort of true. Avoid bumpy weather? it can get pretty bumpy at those altitudes and the only way out of it is down, plus if it is a thunderstorm then they can go way above your maximum altitude so the only way is around them. Gives us more time in an emergency is also not entirely true as the reason for us being up there. Sometimes it is nice in say an engine failure case but in a decompression it is working against you. Which one do you plan on happening??

 

Without having any info on how they have modelled the aircraft, i have found in the F-15, when it is heavy it seems to like to sit around 30,000' but as you get lighter i'd higher, as high as 38,000' virtually empty. I tend to fly 100% N1 to climb altitude and once at a comfortable altitude i bring it back to about 95% and it should maintain speed.

 

The next problem was if you were low and wanted to get back to base the most efficient way. This has a lot of variables that would determine which way you would go. How much fuel do you have and how far is the base. You burn fuel climbing, so if you are really low then i wouldn't bother climbing but bring the N1 back to 80% and just plod along at about 350kts. If there is enemies about then i go 90% and about 450-500kts till i am no longer in a threat zone and then bring it back to 80% as soon as i can.

 

GGTharos - your statement re climbing at M0.9 is a little confusing. Do you take-off and go straight to M0.9 or do you climb at an IAS fist till you reach the cross-over altitude?

 

You will find fighters would climb out at a profile something like 450kts/M0.9 that is they accelerate to 450kts and climb at that airspeed till they reach the cross-over altitude and then climb out at M0.9 (the cross-over altitude is the altitude where you IAS and Mach number meet.)

 

I hope that clears up a few things

 

:rolleyes:

[GGTharos]

NOt for me :) As in why they do that and what that altitude is :D

 

ANyway, I will take off, accelerate to M0.9, then pull the nose up. My take-off isn't necessarily a level acceleration to M0.9, I typically keep the aircraft in a shallow climb, just accelerating at a reasonable pace.