correct as is Can't get the F-15C to spin...

[greyseal494]

bug or not?

 

Edited August 10, 2023 by greyseal494

[BIGNEWY]

Hi, 

please only report one issue at a time, I have moved this thread to the F-15C section, please attach a short track replay example of what you think is wrong and we will take a look. 

 

For issues related to the F-15E you should visit the RAZBAM froum section here 

https://forum.dcs.world/forum/216-f-15e/

[draconus]

18 hours ago, greyseal494 said:

bug or not?

Please, take an effort and describe the issue thoroughly.

[greyseal494]

Well, I never flew a jet but I used to fly little airplanes. I use the same procedure. Reduce power, point the nose up and wait for the break. It never really happens in the Eagle. You just get some kind of tail slide or falling leaf maneuver. Seems to me, and I may be wrong, but shouldn't the nose drop?

[greyseal494]

Surely the USAF teaches stall recovery for F-15 pilots...

[draconus]

Have to agree that no matter what I couldn't get it to spin either even low speed, high alpha, cross controls and CAS off.

[draconus]

11 hours ago, greyseal494 said:

Surely the USAF teaches stall recovery for F-15 pilots...

There's not much to learn, btw [from manual]:

- don't touch the throttle (engine stall risk)

- controls neutral

- retract speedbrake

- if no control regained under 10k ft - eject

So I didn't find anything on spins in the Eagle.

[Ironhand]

On 8/10/2023 at 10:45 AM, greyseal494 said:

bug or not?

 

 

Not.

According to the real world manual, with CAS on or off, you will not get a nose drop. There will be no spin. You might get some wing rock and yaw until you release the stick.

 

[BIGNEWY]

Hi, 

from what I can see this is correct as is, if you have unclassified public evidence it should be different please PM.

thanks 

[GGTharos]

On 8/14/2023 at 8:51 AM, BIGNEWY said:

Hi, 

from what I can see this is correct as is, if you have unclassified public evidence it should be different please PM.

thanks 

There is a lack of yaw/roll coupling, but this is DCS-wide.   This probably affects the amount of stability based on various factors, and is easy to test by applying the auto-roll conditions, you'll see that you cannot produce an auto-roll.

[henshao]

You can easily put the Eagle into a flat spin with split throttles in a stall, although I haven't tested to see if full rudder/opposite stick will induce a stall

 

 

[Buzz313th]

On 8/14/2023 at 5:51 AM, BIGNEWY said:

Hi, 

from what I can see this is correct as is, if you have unclassified public evidence it should be different please PM.

thanks 

There are interviews and books where retired F15 pilots talk about the spin characteristics of the eagle.  I'm sure just reaching out to them will give you the unclassified data needed to model this better. 

I spent an hour last night trying to learn what triggers the code in the FC3 Eagle to spin without asymmetric throttle and the best method I found to get it to depart was with a nose higher than 45 degrees and get it into a tailslide with neutral stick and full rudder or full cross control.  This flight profile put the eagle into a high yaw rate AND put airspeed below 30-50 KCAS, which felt like it triggered something that started a simulated model of departed flight, which resulted in a flat spin.  Recovery early in the spin can be accomplished by opposite rudder neutral stick.  As yaw rate increases, asymmetric thrust is needed to recover.   

During my attempt to spin the Eagle..  I could not get it to depart with the nose between level and 45 degrees high. Accelerated stalls and shallow spin entry resulted in what felt like the onset of a spin, but the yaw rate would dampen, forward velocity would increase and the airframe would casually recover even though I was doing everything I could to get it to depart.

Later on in the test flight, I started working on recovery of unusual attitudes and in a nose low self induced "Washing Machine", I picked my head up and I was in a flat spin.  I honestly have no idea what attitude I put the simulated F15C in that caused it to depart nose low.

So it will spin, it will depart, but based on what I have read, it seems it shouldn't be that difficult to get it there. 

Edited December 4, 2023 by Buzz313th