A few MIG-21 Questions

[LCYCowboy]

Hi All,

 

I have been getting into flying the MIG-21 again (with my Oculus). With VR it absolutely blows your mind!

 

I am having a few problems and was wondering if any MIG 21 experts might be able to help.

 

1) The SAU landing mode seems to induce massive side to side rocking motions. I have tried different airports in the Caucasus, and on approach, when perfectly lined up at the correct speed, when I select Auto Land mode, it rocks from side to side (making me feel quite sick with my VR).

 

2) The landing/Taxi light seem to work fine on taxi out, but after landing back, there is no sign of them on the ground, even though they are definitely on.

 

3) I downloaded a great mission which involves scrambling from Kuboleti to intercept 4 B-52s and shoot them down. The mission has 4 Radar missiles loaded. I went into the mission editor to change this to 2 Radar and 2 IR, but I never get a lock with the IR missiles. Do B-52s not emit enough heat signature?

 

ps. what is the correct pylon numbering. In the tutorial it seems to say 1/2 are the outer pylons 3/4 the inner, but when I fire 1/2, the inner pylons seem to fire?????

 

Soooo many questions.

 

Sorry,

 

Neil

[Frederf]

1. Automatic landing gains, whatever numbers control what input responds to the situation, aren't currently that great currently. Flight model gets changed, gains have to be updated.

 

2. The landing light folds out and is ripped off or damaged by high airspeeds (~650 km/h). Takeoff with it off if possible or if needed after gear up but before flaps up. Similarly landing light on if needed after gear down on approach.

 

3. Make sure to set the station selector to the station(s) for the missile and the priority switch to IR. Also check the missile tone volume knob. Most missiles are rear aspect only and those with all aspect are limited in this mode.

 

Stations are number 1,2 inner; 3,4 outer. Odds are port, evens are starboard.

[Art-J]

1) No idea, haven't tested the SAU for quite a while. Recently the flight model of the MiG went through many changes, resulting, amongst other things, in quite pronounced slow speed roll instability. It's possible that autopilot code cannot cope with new FM well;

 

2) A shot in the dark, but are You sure You retracted the lights after takeoff? They break very easily around 700-ish IAS. Unless they worked OK in landing mode but stopped during rollout, then we might be having a bug to report. Will test later;

 

3) I remember that mission :D. It's difficult to investigate, as we don't know what missiles You changed in the editor and how You prepare to launch them. I would double check if the missile type selector on the left side of the instrument panel is switched to IR, and if the correct pylon is selected. I'm fairly sure though the tutorial gives correct numbering, which is:1-2 inner (left-right), 3-4 outer (left-right).

[LCYCowboy]

Thanks for the quick answers! What a fantastic forum!

 

The landing lights were as predicted operator error. I wasn't retracting them in time, so they ripped off :-(

 

I think the SAU problem is probably linked to the flight model changes. I know that when I came back to the MIG-21, I had real problems on finals, keeping it straight without rocking side to side. I blamed it on my new hardware (I updated from a Thrustmaster 1600 to a Warthog Hotas). I now realise that it is a change to the flight model.

 

Having said that, the reason why I really love DCS (both Helis and fixed wing) is that the flight models have a real feeling of inertia. In FSX/P3D, it always feels like the aircraft don't weigh anything. My real world flying is always a lot easier as you feel the weight of the plane. DCS always manages to put this feeling across a lot more than other sims.

 

The missile problem. I go into editor, change the load to the pre-defined 2xIR 2xRAD (2x3S and 2x3R??), and looking out onto the wing, I have 2 different types of missile. In the tutorial I have no problems, but in the mission I select the IR missile (both the missile selector toggle on the left, and the correct pylon station), but following the B-52s, I never get the lock on beep, or the pipper moving over the target. I can fire the RAD missiles fine, and use my guns, but can't manage to get the IR missiles to fire

[Art-J]

Post the edited mission as an attachment here and we'll take a look. I remember it originally was a bit old mission, so maybe something just doesn't quite want to work right with the newest version of the MiG.

[LCYCowboy]

Sorry about the delay, here is a copy of the mission.

 

The payload is the standard "Short Range"

Mig-21_B52_intrcept_Dusk-cold.miz

[Frederf]

I didn't have problems getting tone on B-52 from the rear hemisphere. I was unable to from the front hemisphere as expected. There might also be a "time since CG heat applied" issue due to the nature of the scramble.

[LCYCowboy]

I gave it another go, and managed to briefly get a lock on the third B-52.

 

It seems a lot harder than in the Tutorial, maybe it is the lower heat signature, or as you said, the scramble time.

 

I absolutely love the MIG -21 in VR. Blows my mind.

 

I landed with 1 missile left. What a struggle. I assume you are supposed to dump unused ordinance before landing?

[Britchot]

I landed with 1 missile left. What a struggle. I assume you are supposed to dump unused ordinance before landing?

 

That would be a waste of the Motherland's ruble! I'm pretty sure you aren't even supposed to drop your tanks unless you absolutely have to, either.

[Frederf]

There are genuine limitations with external stores. A wide variety of approved flight loads are prohibited to be landed with at any fuel state. The normal landing category is 6800 kg with the 7300 kg landing weight being overloaded (3% or less of all landings). Empty drop tank(s) and 2 missiles is OK but 3 or 4 is not (unless the tank is discarded).

 

Asymmetry is allowed up to a S-24/RAB-250 equivalent on an inner station with reduced crosswind limits (8m/s from the same side as the store). Normally minor missile asymmetry would not be an issue especially if the SAU stability mode was well-modeled.

 

It's an interesting academic assignment to take an example store configuration and work out what fuel maximum allows a normal or overloaded category landing or even if it is allowed at all. If some stores have to be jettisoned there is some optimal selection to comply with the rules.

 

If it is beyond limits, jettison. If the mission result is in doubt, jettison it. Landing gear repair is very expensive. Training new Soviet pilot is moderate expense.

[LCYCowboy]

Thanks for the in depth answer!

 

Can I pick your brain further about the SAU stability mode. When should this used by pilots. It seems to have a large damping effect on all controls.

 

Should it be switched on after take-off and off just before combat manoeuvring, and then back on for landing?

 

I have not really used this mode much

[Britchot]

Thanks a ton, Frederf! That was a lot of information that I wasn't aware of. Of course, it is in the manual but I may or may not have completely forgotten about it :music_whistling:

 

9. Rated landing weight for using concrete, un-paved or snowcovered runway, 6800 kgf, BLC system being used by all means. This landing weight is obtained when the aircraft:

 

(a) has no external loads, fuel remainder not exceeding 700 L;

 

(b) carries two missiles, or two UB-16-57 pods, or two FAB-100 bombs, or carries no combat stores but has empty drop tanks attached, fuel remainder being 500 L.

 

This fuel remainder ensures performance of a tight-visual-circuit goaround maneuver and landing, the flight endurance totalling about 6 min.

 

WARNINGS:

 

1. All other, heavier external loads shall be jettisoned before coming in to land.

 

2. The fuel remainder must be at least 600 L before an instrument approach to land under bad weather conditions, in order to ensure the ability to perform a two 180o turn or tight-circuit go-around maneuver.

 

3. The rated landing weight with the BLC system not in use is 6500 kgf. This weight is obtained when the aircraft carries no external loads and the fuel remainder is 400 L.

 

10. Landing of an overloaded aircraft (whose weight, however, should not exceed 7300 kgf) is allowed in the following exceptional cases:

 

(a) when carrying two guided missiles, or two loaded UB-16-57 pods, or two FAB-100 bombs and empty drop tanks, fuel remainder not exceeding 800 L;

 

(b) when carrying two empty UB-32 pods and two missiles or two FAB-100 bombs, or two loaded UB-16-57 pods; when carrying four guided missiles or four loaded UB-16-57 pods; or two missiles and two loaded UB-16-57 pods (two FAB-100 bombs); or four FAB-100 bombs, or two S-24rockets, or two FAB-250 bombs, or two loaded UB-32 pods, fuel remainder not exceeding 600 L.

 

Landings with weights in excess of 6800 kgf shall be made with employment of the BLC system and drag chute in all cases.

 

NOTES

 

1. In the case of landing with four empty UB-16-57 pods or with only two empty UB-32 pods, the fuel remainder with which landing is permissible can be increased by 350 L as compared to the above figures.

 

11. Takeoff and/or landing with one bomb of up to 250 kg caliber or S-24 rocket asymmetrically racked on the inboard station, may be accomplished if the crosswind component (directed from the side opposite to that on which the external load is attached) does not exceed 8 m/s.

Edited December 13, 2016 by Britchot

[Frederf]

Sorry I mean this manual which maybe has more information. http://www.avialogs.com/viewer/avialogs-documentviewer.php?id=15621 Look at Table 6 which starts on page 22. It looks like it is the source for the DCS manual data.

 

SAU stability may be used from takeoff roll to end of landing roll and generally makes flight much easier. If pitch damping (forces) is a concern then the SAU Pitch switch can be turned off and level-recovery functions will be available but normal pitch will be the same as when stability is not used.

 

I recommend reading page 47 onward from link above "Handling Automatic Flight Control System SAU-23ESN." Most of the stability behavior described is not currently seen in DCS (pitch holding, bank leveling, bank holding, trim switch as pitch select). As such the stability program currently has very little practical use.