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Re: Comparison by Spurts

Unread postPosted: 17 Mar 2020, 23:57
by energo
sprstdlyscottsmn wrote:"Okay, .67 to 1.83 happens pretty smoothly, 1.83 to 2.02 takes almost as long, doubles the fuel, and more than doubles the distance"


Probably old news and not very relevant, but one RNoAF F-16A pilot once told me that pushing Mach 1.6 was like "hitting a wall". It wen't slowly from there. Mostly due to the inlet, I was led to believe. Most RNoAF pilots I've talked to have barely had it much past Mach 1.9 in FCSs. As one said, to the effect of: "I couldn't bother trying Mach 2. Not enough fuel!" This was way before the -220E, so it might not be accurate today.

Re: Comparison by Spurts

Unread postPosted: 18 Mar 2020, 00:03
by sprstdlyscottsmn
energo wrote:
sprstdlyscottsmn wrote:"Okay, .67 to 1.83 happens pretty smoothly, 1.83 to 2.02 takes almost as long, doubles the fuel, and more than doubles the distance"


Probably old news and not very relevant, but one RNoAF F-16A pilot once told me that pushing Mach 1.6 was like "hitting a wall". It wen't slowly from there. Mostly due to the inlet, I was led to believe. Most RNoAF pilots I've talked to have barely had it much past Mach 1.9 in FCSs. As one said, to the effect of: "I couldn't bother trying Mach 2. Not enough fuel!" This was way before the -220E, so it might not be accurate today.

I'm analyzing the -129

Re: Comparison by Spurts

Unread postPosted: 18 Mar 2020, 00:21
by energo
sprstdlyscottsmn wrote:I'm analyzing the -129


Absolutely, keep up the good work! :mrgreen:

Re: Comparison by Spurts

Unread postPosted: 18 Mar 2020, 02:00
by rheonomic
sprstdlyscottsmn wrote:Working on the thrust model for the F-16.

It's probably a shitty model but NASA TP-1538 (PDF) has a static engine model as a function of PLA, Mach, and altitude for an "F-16 like" aircraft. There's also an aero model that might be ok to ~M0.6 or so. There's a MATLAB version of the reduced model the Stevens & Lewis textbook has available here for non-commercial use.

Re: Comparison by Spurts

Unread postPosted: 07 Apr 2020, 12:07
by eloise
New AIM-120C model in DCS, closer to real life?

Re: Comparison by Spurts

Unread postPosted: 07 Apr 2020, 15:32
by sprstdlyscottsmn
There are a few takeaways from that video.

Aspect: These were head on shots.

Launch conditions: 1.6M from 50,000+ft... hmm, isn't there some Wunderjet that cruises at those kinds of conditions where it was stated it would roughly double launch ranges? Now it is highlighted why. The missiles were able to stay faster for longer in rarified atmosphere.

Target dynamics: The targets were all at high altitude so the missile never had to slow down in thicker air. The targets did not have much time to maneuver either so they did not have the opportunity to generate lateral separation.

Crunching numbers on the three shots

50nm shot, 64s time of flight, actual flight range 40.4nm (target covered the rest)
55nm shot, 74s time of flight, actual flight range 43.9nm
60nm shot, 75s time of flight, actual flight range 45.6nm

Re: Comparison by Spurts

Unread postPosted: 08 Apr 2020, 16:20
by sprstdlyscottsmn
Update: No update right now. During the midst of all this craziness I am also changing jobs and moving cross country.

Re: Comparison by Spurts

Unread postPosted: 08 Apr 2020, 17:23
by lamoey
sprstdlyscottsmn wrote:Update: No update right now. During the midst of all this craziness I am also changing jobs and moving cross country.


I'm please to hear that you have a job, under the current climate.

Re: Comparison by Spurts

Unread postPosted: 09 Apr 2020, 02:42
by eloise
sprstdlyscottsmn wrote:Update: No update right now. During the midst of all this craziness I am also changing jobs and moving cross country.

It is scary, I hope US find out the cure soon

sprstdlyscottsmn wrote:There are a few takeaways from that video.

Aspect: These were head on shots.

Launch conditions: 1.6M from 50,000+ft... hmm, isn't there some Wunderjet that cruises at those kinds of conditions where it was stated it would roughly double launch ranges? Now it is highlighted why. The missiles were able to stay faster for longer in rarified atmosphere.

Target dynamics: The targets were all at high altitude so the missile never had to slow down in thicker air. The targets did not have much time to maneuver either so they did not have the opportunity to generate lateral separation.

Crunching numbers on the three shots

50nm shot, 64s time of flight, actual flight range 40.4nm (target covered the rest)
55nm shot, 74s time of flight, actual flight range 43.9nm
60nm shot, 75s time of flight, actual flight range 45.6nm

Thank you

Re: Comparison by Spurts

Unread postPosted: 18 May 2020, 16:59
by sprstdlyscottsmn
Okay, so now I do have an update! I have "finalized" my F-16V model. Now on to mission work.

Re: Comparison by Spurts

Unread postPosted: 19 May 2020, 02:35
by sprstdlyscottsmn
I swear, 100 hours to make the model, and in 5 hours after that I have have the analysis work done.

Re: Comparison by Spurts

Unread postPosted: 19 May 2020, 02:44
by eloise
sprstdlyscottsmn wrote:I swear, 100 hours to make the model, and in 5 hours after that I have have the analysis work done.

I knew your model take very long to make but holy **** 100 hours, I'm deeply impressed.

Re: Comparison by Spurts

Unread postPosted: 04 Jul 2020, 03:23
by sprstdlyscottsmn
So, I made a statement about 5 hours getting what I estimated to be half of the analysis work done. I took the time to count the rest. 280 minutes to finish, or just over 4.5 hours. The Viper is finished. On to the Super Hornet and the last thing I have a manual for.

Strike Fighters 2025_5.pdf
(1.07 MiB) Downloaded 33 times

Re: Comparison by Spurts

Unread postPosted: 04 Jul 2020, 05:19
by 35_aoa
energo wrote:
Probably old news and not very relevant, but one RNoAF F-16A pilot once told me that pushing Mach 1.6 was like "hitting a wall". It wen't slowly from there. Mostly due to the inlet, I was led to believe. Most RNoAF pilots I've talked to have barely had it much past Mach 1.9 in FCSs. As one said, to the effect of: "I couldn't bother trying Mach 2. Not enough fuel!" This was way before the -220E, so it might not be accurate today.


With a centerline tank/pylons (or in a -B) yeah, I remember 1.6 being about where the ride got rough and things slowed down. It's been a while, but I remember a completely slick -A moving pretty steadily up to about 1.8 and then hitting the proverbial brick wall. I know one guy who got it to 1.99......nobody who bested 2.0, though I know it has happened plenty of times.....I believe an A was lost in the early years exceeding the mach limit (memory is fading now and don't have a -1 to reference, but I seem to remember 2.01 or 2.02M being the lim) in a dive, when the engine turbine section (or something of that nature) disintegrated violently and ripped the airplane apart.....maybe gums remembers that tale that was told to me many many years later when learning to fly the same old bird.

Re: Comparison by Spurts

Unread postPosted: 04 Jul 2020, 13:41
by sprstdlyscottsmn