cheezit

You ever heard the old saw about RHA equivalence and weighing pigs in Arkansas? :V

What kills me is that the F101-DFE experiment started in 1980 or 1981, did some test flights demonstrating mil-power cat shots and limited supercruise, then immediately got shelved for something like six years until it was restarted as the F110 project that eventually was used in the F-16 '0' blocks, F-14B/D, export F-15s, etc. The whole thing probably could have been done much sooner if it weren't for the fiscal pressure on the program in that particular year, and the recent failure of the Navy's part in the ATE/P&W F100 program. This is the same timeframe when the Navy dramatically reduced planned purchases of spares for the F-14 in a penny-wise/pound-foolish attempt to save money. I don't know if I can pull it up now but there was a Q&A segment of one of the defense appropriations hearings transcripts where the Navy either demonstrated complete ineptitude or lied through their teeth to Congress about the long-term costs of purposefully not buying enough spares.

e: I hadn't seen GGTharos's posts when I wrote this The scenarios are entirely different kettles of fish in terms of what the missile might try to do: A SARH or ARH air-to-air missile going into home-on-jam mode against a target with a self-protection jammer trying to jam the fire-control radar that is guiding the missile, where the self-protection jammer is probably not emitting anything when the fire-control radar isn't illuminating it An anti-radiation air-to-ground missile passively tracking an emissions source in either search or fire-control mode, such as a SAM antenna A SARH or ARH air-to-air missile going into home-on-jam mode against a standoff jammer (cf. Wahoo's story about an AIM-54A switching to HoJ against an EA-3B in flight ) where the jammer *may* be emitting noise or what we will call "something that isn't merely noise" constantly, even if there's no fire control radar illuminating either it or whatever it's trying to protect

PILOT: Why can't you find these @#$%! bandits? RIO: Good luck finding them yourself! *rocketjumps out of the plane*

For a while, many players cursed with an emotional attachment to the AIM-120C5 being some sort of wunderwaffen complained that the blitting/blinking mode of the F-14's jammer trashed the missile, since ED's implementation of HoJ would basically make the things waggle at the frequency that the F-14's jammer blinked on and off and thus bleed energy very quickly. I think ED eventually fixed this broken HoJ transition logic, though it should be noted that building miss distance to kinematically defeat a missile this way is definitely part of a self-protection jammer's playbook. Many of these same players complained that the AIM-54 (on the old missile API, vice the new API that the AIM-120 was on by this point) was either unaffected or much less affected. Nb. that the AIM-54C, way back in the test phase in 1980/1981, was being designed to defeat and tested against multiple simultaneous standoff blinking jammers, blinking self-protection jammers, etc. and got a new dual-principle target detection device (to avoid a single-principle TDD from getting spoofed by a bomber's self-protection jammer and prematurely detonating outside lethal distance) and lots of other ECCM goodies that largely weren't in-scope for the AIM-120A, which (as the Air Force strenuously emphasized during hearings) was at that time meant only to replace the AIM-7, which had dramatically less ECCM capability than the AIM-54A. Of course, the AIM-54C latter got the ECCM/Sealed upgrade, the "High-Power Phoenix" upgrade (travelling wave tube stage in the antenna, consolidation of a bunch of older digital components into a smaller number of faster and more capable ones, etc), an eventual combination of these two upgrades, and had reprogrammable code and data memory from the get-go to allow continuous updated to the ECCM logic (and other aspects of the missile). And the AIM-120A was replaced by the AIM-120B, AIM-120C and its subvariants and so on which eventually gained reprogrammable memory and generally became more kinematically capable and more ECCM-capable as technology improved and it became more feasible to fit enough DSP capability into the available board space, as well as more necessary to improve the AIM-120 to pick up the slack from the cancelled AIM-152 and the AIM-54 which was slated for retirement by then.

Heatblur guys ( @LanceCriminal86 @IronMike etc): does the new availability of detailed technical information on the APG-70 (RDR-3, AGR-2, AGR-3, etc) thanks to the lively lads at the WarThunder forums help at all with modeling the APG-71, which Hughes created more or less by mating the APG-70 (swapping in a faster CPU) to the antenna from the AWG-9? I'm mostly kidding :V

I wonder proportionally how much of the benefit is from each of the following: a) Having a vertical component of the launch platform's velocity vector is more efficient than not when the missile is going to climb anyways b) The loft profile on v1 of the missile API is bad for the Phoenix's burn profile and aerodynamics, and manual loft forces a less-bad loft profile c) The transition to the terminal phase of the intercept on v1 of the missile API is bad for the phoenix (though not as bad as it was before Heatblur tweaked some things on their end), and the parameters during this transition are more in line with what the API can handle without bleeding a bunch of speed when manually lofting than with the default loft profile I also wonder whether it is necessary to over-lead the "T" when manually lofting against offset targets, since the time of flight will be slightly longer than what the WCS expects.

It would also useful to be able to threaten to do so if the pilot misses the basket too many times (cf. 10:13 through 10:34 in this: )

What if the reentry vehicle also has glove vanes?

I seem to recall that Victory205 at some point mentioned that, in addition to their normal function of curing cancer and their ancillary function of moving the Cl forward slightly at supersonic speeds (to avoid over-stability in pitch), the glove vanes also were useful to increase the vapes (eg. during an airshow). Since we have no glove vanes, it is thus appropriate that we have no vapes. It's Science(tm).

I don't think the nozzle_exit_area business is related to this - my understanding is that that coefficient is only used for correcting base drag while the burn is ongoing (less weird turbulence when there isn't a low pressure area right behind the base) and does not affect thrust. Happy to be corrected if I'm wrong here. What coefficients control this for the DCS engine? I don't see anything with a name that looks related. Obviously applying a standard curve won't work correctly, as depending on nozzle design, propellant chemistry etc. the difference between sea level and vacuum thrust and Isp can plausibly be anywhere from 1.1x to 2.5x. If there's some curve being applied that has no coefficients I'll go back and edit my post to correct it, but I've never heard of this before your post. Thanks for running this analysis. Did you export that from TeX btw?

Nb. that DCS also doesn't model the change in Isp based on atmospheric pressure at all. While a typical missile has a nozzle that's optimized for low altitudes (and thus with a relatively low spread between the sea level ISP and the vacuum ISP), there's still probably a 7% or so difference between a sea level shot and a 35k foot shot that Heatblur can't do anything about, with the difference being a bit more for a higher shot, if we use other SL-optimized solid rocket motors with similar propellant chemistry and known characteristics as a model. I'm guessing the Isp used in the in-game model is correct for intermediate altitudes, causing the thrust to be slightly higher than it should be for the portion of the motor burn that occurse down low and slightly lower than it should be way up high, bounding the worst-case error, but I'm obviously not privy to that. Another oddity: do the Mk47 Mod 0 and Mk47 Mod 1 really have the same Isp and total impulse despite having different propellant chemistry? The whitepaper (I know, I know, it's "no longer operative" and whatnot) claimed the Mod 1 had a higher Isp and thrust, the previous in-game model had the Mod 1 with *lower* Isp and thrust, the current in-game model has the Mod 1 and Mod 0 with the same Isp and thrust (unless I'm missing something in the files, in which case please correct me). It's probably a marginal difference, but it seems really odd that a change to a propellant with a different energy density wouldn't change the total impulse.

I'm guessing it involves continuing the ~0.9M climb past 30k feet to 40k or so, unloading, accelerating in a dive until you're somewhere between 1.2M and 1.4M, then climbing at constant speed to your desired altitude. Am I warm or am I cold?

Are you getting a max mach of 1.825M for the F-14B in that configuration at 35000 feet from Figure 8-5 on page XI-8-19? Because several other charts disagree. For 2x2x2 at 35k feet, Figure 9-5 on page XI-9-34 shows the PS=0 line crosses 1g at 1.95M. Cross-checking via Figure 9-2 on page XI-9-7, it also shows max mach in that configuration at 35k feet as approximately 1.95M (I'd call it 1.94, but the line is probably 0.02M wide and that's some real fine hair splitting). I'm too dumb to understand why there's an apparent disagreement between the Level Flight Acceleration diagram on the one hand, and the Specific Excess Power and V-N diagrams on the other hand, but I think it's worth noting if we're trying to determine whether performance in the sim matches the charts. Nb. for some parts of this testing, Figure 8-6 may be a useful cross-check. It certainly would be neat if the aircraft could be scripted to try and fly those profiles with those loadouts.

Is the missile modeled as having a PD-STT lock on the target aircraft where there is a defined filter of X knots around the doppler region where Vc is close to Vg, and in a look-down situation the target aircraft can get lost in the ground clutter when inside the doppler notch in the same way that an AWG-9 PD-STT lock can get broken in the same scenario? Or does DCS model missile notching in a more abstract manner (as it does for chaff, jamming, etc) where there is eg. a diceroll or something when (Vc - Vg) < clutter_filter_width ? Thanks for doing extra duty on community relations wrt. this patch btw

So when do we pen an apology to that old troll (nick had something to do with counterstrike if memory serves) that used to post on AIM-54 threads, now that the missile model has been changed more or less to how he thought it should be in terms of kinematics, chaff resistance, etc?

Are the MBAM and the loft one continuous maneuver in the model for DCS?

What was the deal with aircraft #98?

My suggestion is to not worry so much - it makes life much less stressful if you just relax and let the chips fall where they may. To borrow a phrase, caedite eos! To borrow another phrase, Raytheon Technologies doesn't give a hoot, continuous rods stick to pilots. Why yes, I like the GS server, why ever might you have asked???!

You alternate between saying the Tomcat is a 6g plane and a 7.5g plane quickly enough to give yourself whiplash, get calculations wrong by more than a factor of two, ignore the copious evidence contrary to your assertions, ignore Grumman's calculations that structural failure is expected at 13g (which would lead to load factor limits of 8.67g with the normal 1.5x safety factor standard in the aviation industry), engage in wild hyperbole that aircraft that were either fine or had minimal damage (jammed slats, bent torque tubes) were "destroyed in seconds" - are you even attempting to argue in good faith here, or is this merely a trolling exercise?

I'm not a party to this, but I'll dispute it. 100 m/s is 194 knots. 430 knots is 221 m/s, 380 knots is 195 m/s.

Too many thoughts for me to congeal into writing over lunch. One question though: which episode were they referring to that had controversial content in it? I can't remember anything that raised a ruckus.

In other parts of the software engineering world, the term of art is Real Soon Now.

How does the AI's RWR differentiate between being STT'd with no launch versus being STT'd with a launch?

Nb. that Puck did another very interesting interview about three weeks ago, wherein he touched on a whole lot of topics: