Zephyr Net

For the moment I'd have two questions about editing aircraft...

I've assumed that the max speed at altitude one sees under the "Control" tab in FATK is the Vmax of the aircraft, and *not* the Vne; so how/where would one input the Vne of the plane?

The second question is: I've found turn rates and such, but nothing for rate of climb... I'm not a physicist at all, but now I'm suspecting that has something to do with the thrust to weight ratio of the plane? I recall reading somewhere that thrust isn't well represented in the game; is this simply a case of the values not being input correctly (and thus could be corrected by going through each type), or is it something more complex?

Thanks!

Another question I just thought of... would it be possible to make JATO pods and rocket booster engines (as was used on some early experimental versions of the MiG-21, for example)?

1st question... Ask Kaptor...

2nd question... You can do it 2 ways...

You can setup a huge power increase with afterburner in the PT so that you can launch yourself with afterburner (but of course this means you have no realeastic afterburner speeds inflight, it will be to strong)

Or you can simulate the smoke cloud of the launch by making smoke pods, but you will not get the high thrust effects...

So, to answer your question, essentially no you cant do it unless you are trying to simulate the RATO/JATO on a subsonic aircraft that has no afterburner in regular flight (Like the F-80 thru the F-89 and similiar Navy jets like the F9F Panther and the F2h Banshee, FJ3 Fury, A4, A6, and A7) or bomers lik ethe B-47 and transports like the C-130, becasue then you could build the super afterburner and add the smoke pods to simulate the blast (smoke pods only turn on on afterburner IIRC, but I could be wrong) and then ignore the afterburner setting for the rest of the flight...

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Expanding on what CAG says above, you could make the RATO/Afterburner fuel consumption so prohibitive that you won't want to use it any more than absolutely necessary. I did this with my YMC-130 Commando Solo (Iran hostage rescue plane). This will at least deter the player from jetting around in a massively overpowered aircraft in horizontal flight.

Zephyr

A new question... I'll just stick all my questions into this thread.

What formula is used to calculate the damage points assigned to aicraft, ships, armour and structures?

Edit: and another question: how is the value of drag coefficient defined? The number visible in Toolkit seems to be 256 for all aircraft, but this doesn't look like any drag coefficient value I know of. Relatedly, how to calculate the additional G Pull Drag value?

I based my damage points by those I selected for specific weapons that I have 1st hand knowledge of...

Another words, I know a 500lb bomb will kill a specific target if it hits it dead on, but that same target will likely survive with just moderate to slight damage in a near hit, so I value that target with enough points to survive all but a direct hit by that specific weapon. And so on, and so forth...

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Okay, so I guess as long as the scale is fairly constant (re DPs) things should be okay... I think I'll try playing around using the equations from the old GDW "Harpoon" game, adjusting things as needed.

I've based calculations for game-value drag coefficients on the "proper" equations, adjusted/modified somewhat... hopefully this will be another instance of "if the scale is constant, it'll be okay"...

i actually found the thrust on FA accurate. The only obvious flaw with FA is physics detail in terms of game action speed. Things are slow, if only the game could be modified so that every knot is multiplied by x1.5 so for example if your flying at 350 knots, it would be displayed as 230. This way plane flies faster, of course this will mean you also need a larger map since u have to scale distance as well.

btw can you add smoke trail to aircraft? that would be really awsome.

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So what you really need is smaller object scale?

I've decided I'm not going to bother with graphics and such other things until I can figure out wth I'm doing with the flight model. FATK seems to have a very opaque interface (and limited one!) for adjusting aerodynamics and other aspects of the flight model...

I've been able to get the landing speed range fairly close to what I want (I'm working on a Ye-5/MiG-21 Fishbed-A for starting; the landing speed range between stalling and safe max is fairly tight). Takeoff/unstick speed has been annoying, but its within 25 kts of what it should be... (but you have to yank back hard on the stick to about 14 degrees to get off the ground, otherwise you won't get up and you die...).

I adjusted the thrust (dry and reheat) with the correct value for the AM-11 powerplant, adjusted the empty and MTOW values, the drag coefficients, ceiling, etc... and then I did some climb and speed tests. Having the results of one of the Ye-5's test flights for rate of climb, I compared... and what I got in the game was NOTHING like reality. To the 57,910' ceiling it took in-game barely half the time it took the actual aircraft, and at an indicated speed of around 360 knots - at full reheat - where the actual should have been 840. Speed testing was similar, though better, though I could have gone faster than the Vne (whereas I think the speed I wanted, was the *max* the engine could push the aircraft...)

I have rather extensive data for this airplane, turning radii and turn times at various altitudes/g forces, speeds at altitudes etc... but either I'm dense, or there isn't much way to input these in FATK. Also, I think the Drag coefficient value they use is rather off, and I'm still not sure I've found a good translation for the *real* C_D value.

Not looking for in-depth lessons here, but could someone suggest me where to look in a PT file (either in text or hex or wherever) to modify the flight models?

I found the "PT file explained" file at FARC... helpful - a few things clarified that weren't quite clear before, but still a lot of questionmarks.

I did some further adjustment and testing of my Ye-5/MiG-21 Fishbed-A.

With regards to the Drag coefficient question, I decided to try using the C_d, not C_d0, for the value to enter for the PT file (Aerodynamic drag); the value was 371 this time, with a 26 for the G Pull Drag value (rather arbitrarily arrived at by dividing the empty weight by the 371). To testing.

I found the unstick speed on takeoff (with reheat, clean - full fuel but no weapons) to be 110 kts (as against 156.6 kts in reality).

In the earlier test with the AeroDrag at 144 and G Pull Drag at 68 I reached a Vmax of about 1070 kts at 32,840 feet (compare with 1064 kts at 35,400 in reality) with reheat. With the newer values, a completely different story:

at 57,000' (ceiling is 57,910'), reached 594 kts with reheat, level
at 35,000', reached 758 kts with reheat, level
at 32,000', reached 730 kts with reheat, level
at 30,000', reached 742 kts with reheat with a -2.5 degree AoA, ending at 26,000'
at 16,800', reached 608 kts with reheat/

The values on the real thing during test flights were 1064 kts at 35,430', 983 kts at 35,100' and at 35,695', and 740 kts at 16,860', all with reheat. This suggests my AeroDrag value is too high.

However!

With the earlier (lower) AeroDrag value, the time-to-altitude test gave a result much too fast - 1:30 from 16,400' to 57,910' with reheat at a 10-15 degree AoA, compared with 5:38 for the real thing for the same climb. With the newer drag value and climbing at a 7.5-10 degree AoA, the result was much closer to the actual Ye-5's performance - sorta - from 16453' to 57917' in game I made the climb in 5 minutes; the Ye-5 made that same climb in 5:38. However, the Ye-5 started the climb very fast: from 16400' to 32810' climbing at 23620 ft/min, dropping to 98 ft/min from 55,770' to 57,910'; my climb from 16453' to 32816' took 1:07 (9175 ft/min), dropping only as low as 4943 ft/min for the ascent from 55775' to 57917'. The climb from ~32.8K to 36K was almost identical between the game and the real Ye-5: I did 32816' to 36083' in 22 seconds for 8910 ft/min, where the Ye-5 did 32810' to 36090' in 22 seconds for 8946 ft/min.

Also of note is that the Ye-5 did the entire climb from 36090' to ceiling at Mach 1.27, whereas I reached a max of 549 kts (Mach .93 at 30K - at 30K I was at Mach .91) climbing from 36083' to 42649', with the speed dropping to 518 kts (Mach .9) from 55775' to 57917'.

How much does airfield altitude matter in FA? If it does matter, the tests of the Ye-5 happened at Zhukovskiy in Moscow, whereas I was flying out of a field in Cuba right near the coast (only because it's the default map on the "Create Pro Mission" in FA).

So I'm a bit puzzled as to what to do now. With the higher AeroDrag value my time-to-altitude is relatively accurate (even if the time between altitudes is off), but I can't reach anything near what I should reach as Vmax (1060 kts at 35K'); but with the lower value, I reached the Vmax fine (1070 kts at 32K'), but the time-to-altitude was ridiculously fast.

Any suggestions?

just a questions, is this a whole new pt file or a modified one? if not, then you should modify the flight envelope and as we don't know the exact flight envelope of the aircraft in question, then we cannot make a real life fighter. there will always be inaccuracy. i spent 2 months modifying an f-14 so as it would perform like the real thing, it never did. there is always a trade off in FA.

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Belly full of HELL

btw what is this? i found it in pt file:

;-------------------------------- F-16
; 4G area = 0.297000
; 5G area = 0.228000
; 6G area = 0.187000
; 7G area = 0.160500
; 8G area = 0.113700
; 9G area = 0.068700
; 39 = rating for F-16

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Belly full of HELL

I've not created a brand-new PT file, just been modifying the hell out of the MIG21.PT file, just because that already has the correct (well, correct enough for the moment) shape file associated with it; the rest of the numbers are fairly gibberish for any variant of the MiG-21, though based on the numbers my best guess is that the default MIG21.PT is trying to masquerade as a MiG-21bis.

I have fairly extensive information on the performance of the different versions of the MiG-21, so perhaps I can try to cobble together envelope maps for at least a few of them; if I could get such done for the MiG-21F-13, PFM, MF and bis I would be content enough (though not enormously happy). In any case I've thought of a couple of things to try out, we'll see how it goes. Part of it is trying to toy with the envelope diagrams based on the data I have to hand, the other (which I'd consider more a fall-back position in case I can't work it any other way, is to find the right value for Aerodynamic Drag that will bring the PT closest to both time-to-altitude and Vmax as possible.

As for the second question... no idea. I tried dissecting some of the numbers in the flight envelope to see if the ones in your list relate to it somehow.

The MIG21.PT (or should I be more accurate and say my YE5.PT) file (which I have toyed only a very tiny bit with the envelope itself, trying to get a correct unstick speed), has this:

;-------------------------------- MiG-21
; 4G area = 0.292000
; 5G area = 0.209200
; 6G area = 0.157200
; 7G area = 0.087900
; 8G area = 0.023550
; 12 = rating for MiG-21

(Idea, pausing to make a quick check...)

Okay. I changed the 4G envelope completely (to an extremely different map), but the value in the PT file remained unchanged.

So now, test second idea: I changed the value of the 4G entry to .333000 and checked for any changes to the envelope in FATK, but nothing; so, 2b, changed the rating from 12 to 55, but still I see no change either in the envelope or under the aerodynamics tab. Maybe someone already knows what these values represent. I don't know right now, but perhaps later I'll play around with them.