Cruising speed and altitude

[Arclight]

This is one has been causing me some grief: is there any way to determine a proper cruising speed and altitude for aircraft?

 

For example, I can find the cruise speed for a Su-27; it's listed at 838mph/1350kph, but that still doesn't tell you at what altitude it's the most efficient.

 

I'd like to set up some CAP missions where the units stay airborne for as long as possible, but I really haven't got the faintest of how to determine whether they are using their fuel efficiently or not. :noexpression:

[vanir]

Pure speculation here but nevertheless:

they're mid range alt for efficiency so it'd be around 8500 metres (a Hornet would be around 7000 metres and a Foxbat 10500 metres, F-15 around 9000 metres).

What you'll want is economy cruise, about 75% power? The Mach 1.1 figure you've got there will be maximum cruise, about 90% power? (same as a Hornet, as I suspect it isn't adjusted for alt...ie. I'm saying the max cruise would be more like 760mph adjusted). Economy cruise (max) should be around 0.85M (about 580mph at altitude)

 

could be wrong but it just seems to me the Flanker wouldn't have a higher max cruise than a clean Hornet, which is 1.1M at alt

Edited June 3, 2010 by vanir

[Robin_Hood]

If it can help, here are two charts that I made. Please note, they are for the Su-33, FC1 (Lock on 1.12), and a clean loadout. I haven't had time to make it for FC2, and I suspect they will differ.

 

It'll give you the best airspeed for max range or time (endurance) at different altitudes

 

Fuel flow against

 

 

Specific range

 

[vanir]

keep in mind though attaining altitude burns fuel you'll have to factor into the flight plan for best overall consumption on the mission. Again I'm no expert or even that experienced in LOMAC but the impression I have is that less is more where fuel consumption/altitude are concerned in objective terms.

 

just anecdotally I was in LOMAC in the Su-27 with a full A2A loadout and found 8000m and 0.8M just felt really nice and was good on fuel, for whatever that's worth.

Edited June 3, 2010 by vanir

[GGTharos]

The fuel consumption in the above charts is probably too low, especially at high altitudes.

[Robin_Hood]

You mean, compared to reality ? It wouldn't surprise me, I must say. It was that way in 1.12 (all datas coming from in-game testing with little to none prediction), maybe they are higher in FC2. But it is a long and harassing task to make those, I don't know if I'll be able to motivate myself into upating them

[GGTharos]

I think consumption is a little more realistic in FC2 yes. :)

Don't worry about making the charts, actually I had a fuel flow system programmed to gather data like this for FC1, maybe I'll do it again for FC2.

[Robin_Hood]

Yeah, a fuel flow gauge would be much more efficient. Not to say that charts aren't a good thing (real flight manuals offer this kind of charts), but fuel flow is easier to use in flight, and does make a lot easier to make charts (if they are accurate enough).

 

Looking forward to that ;)

[GGTharos]

The system I had displayed fuel flow (PPH) as well as range and endurance based on your current fuel flow and ground speed :)

[Arclight]

Wish we had a throttle slider to use for the AI, instead of setting a speed.

 

Or an auto-option; set speed to 0 and the AI sets it for cruise, same for altitude.

 

And have proper speeds and altitude depend on the mission-type.

 

 

Yep, throttle-indicator and IAS would be real nice feedback for AI aircraft (hint hint :music_whistling:).

 

 

Ow well, guess it's some more trial and error to get it right for now... not like we're not used to that with the editor, right? :D ;)

Thanks for the input. :thumbup:

[Robin_Hood]

You can always do the conversion when in the editor. Granted, not a perfect solution

[vanir]

That's actually a really good point. One of the things which weirds me out in mission building is AI interceptions with a short range fighter (MiG-23 or 29), is the way they're so heavy handed with burners climbing/accelerating even if you set an interception speed that's attainable dry, if the target is any proportion of their normal combat radius they start running out of fuel and RTB well before interception. With AI and short range fighters they're only usable if the target is timed to be pretty much right over their base when they're launched.

 

It'd be fantastic if there was a selection of whether or not AI planes were free to use afterburners at each waypoint in the mission builder, so you set a waypoint and select action, and tick a box whether their afterburner is free.

That'd do it, if it were possible.

[Svend_Dellepude]

Second that. always thought it was a little weird to set the speed like that. A throttleslider or maybe, like in F4, you could set TOT?

 

cheers

[jbrking]

Wish we had a throttle slider to use for the AI, instead of setting a speed.

 

Or an auto-option; set speed to 0 and the AI sets it for cruise, same for altitude.

 

And have proper speeds and altitude depend on the mission-type.

 

 

Yep, throttle-indicator and IAS would be real nice feedback for AI aircraft (hint hint :music_whistling:).

 

 

Ow well, guess it's some more trial and error to get it right for now... not like we're not used to that with the editor, right? :D ;)

Thanks for the input. :thumbup:

 

Good idea :thumbup:

 

Wish these sorts of topics were covered within the DCS encyclopedia.

Edited November 14, 2013 by jbrking