MSL PREP versus SW COOL switches (center panel)

From what I understand, the SW COOL switch will start the process of cooling down the sidewinder seeker head. I also have heard/read that the coolant is finite and can run out, so the switch should be off when not in combat.

What I want to know is:

- is the coolant actually modeled and can it really run out?

- does MSL PREP also have a similar finite resource that needs to be preserved?

If MSL PREP only attaches the linkages and programs the missiles for use, is it something I can switch on during my startup procedure and then forget about? Or for some reason should I also be switching off MSL PREP when I'm not in any immediate danger?

The Heatblur manual doesn't really explain this, and I couldn't find anything specific in NATOPS.

From what I've researched, the SW Cool is just for cooling the seeker head of the sidewinders, as you said, and it is limited to about 2-5 minutes of cooling. The MSL Prep switch is for Sparrows and Phoenix missiles guidance (mainly Phoenix). Think of it as seeker head alignment, similar to the Maverick align on the F18 and A10. It gets the missiles ready for launch and makes sure the targeting computer is sending the proper data to the missile. It takes approximately 1-3 minutes to align the missiles, so I usually switch it on prior to takeoff. Also, as soon as you turn it off, the missiles will lose all of the targeting data and have to be re-prepped to be ready again.

Hope this helps.

From what I've researched, the SW Cool is just for cooling the seeker head of the sidewinders, as you said, and it is limited to about 2-5 minutes of cooling.

2-5 minutes? IIRC, it was discussed before and stated it was around 90 minutes.

as you said, and it is limited to about 2-5 minutes of cooling.

The coolant for the AIM-9L/M should last roughly 150 minutes (at least per the video below) from the time you press the SW COOL switch.

Thanks for the replies. I'm going to include MSL PREP in my preflight unless it's somehow harmful to something in the jet.

Saves me a button my throttle.

DECK-LAUNCHED INTERCEPT PROCEDURES

Note These procedures assume that a quick reaction, full-mission-capable launch is essential. Prestart procedures and cockpit configuration may vary in accordance with airwing policy and specific EMCON conditions. All CNI equipment, as applicable should be placed in ON or STBY, all SAS switches ON, and the HYD TRANSFER PUMP switch should be in NORMAL before application of electrical power. The LTS, INST, EMERG GEN, and DFCS IBIT tests on MASTER TEST panel should be conducted and verified during periodic aircraft turn-ups. Compliance with the takeoff checklist is mandatory to ensure proper aircraft configuration before launch.

7.8.1 Pilot Procedures

1. External electrical power — ON.

2. Seat — ARM.

3. Fire detect — Check.

4. Left engine — IDLE.

5. Right engine — IDLE.

6. OBC — Select.

7. MSL PREP — ON.

8. SW COOL — ON.

9. OBC — Deselect.

10. Hook operation — Check.

11. Takeoff Checklist.

12. Ordnance crew — Arm.

Seems like the ready 5 procedure included MSL PREP and SW COOL enabled on the deck before takeoff.

That's the video, I was thinking of, and I totally misheard hours. I thought that it seemed kind of low.

Not that it's going to be exactly the same as the earlier Tomcat, but in one of the manuals for the DCS Hornet, the IR COOL switch was described as for cooling the IR seeker head to be better able to discriminate and track heat sources than if not engaged, that it took about 5 minutes to achieve maximum cooling effect, and that (in the Hornet) it would cool the missiles for about 3 hours.

I think the cooling increases the contrast for the seeker, making better seeker performance.

Now, a couple of things: these systems are not all the same. On Navy Sidewinders, the cooling tank is inside the missile, while the Airforce features cooling tank is inside the launch rail. Different cooling gasses too, I think one uses CO2 and the other Nitrogen N2. It's likely that earlier versions may have had much shorter "cooling" endurance as stated in this thread.

I'm not sure if early 'Winders used this kind of cooling at all, for instance during the Vietnam war, anyone know about this? I do know there was a very drastic improvement in Sidewinder performance once the Lima showed up, before that it was just "ok".

I think the cooling increases the contrast for the seeker, making better seeker performance.

Increases contrast above zero would be more accurate. IR sensors that require cooling generally don't work at all without it. That said, there is such a thing as an uncooled IR sensor today but they're designed differently to work without cooling.

https://www.flir.com/discover/rd-science/cooled-or-uncooled/

Are either of these prep modes modeled with the DCS F14? Or are they both infinite?

I've been pressing the Sidewinder Cool and Missile Prep buttons as part of my startup since buying the place and never noticed any ill effects.

DECK-LAUNCHED INTERCEPT PROCEDURES

 

Note These procedures assume that a quick reaction, full-mission-capable launch is essential. Prestart procedures and cockpit configuration may vary in accordance with airwing policy and specific EMCON conditions. All CNI equipment, as applicable should be placed in ON or STBY, all SAS switches ON, and the HYD TRANSFER PUMP switch should be in NORMAL before application of electrical power. The LTS, INST, EMERG GEN, and DFCS IBIT tests on MASTER TEST panel should be conducted and verified during periodic aircraft turn-ups. Compliance with the takeoff checklist is mandatory to ensure proper aircraft configuration before launch.

 

7.8.1 Pilot Procedures

 

1. External electrical power — ON.

2. Seat — ARM.

3. Fire detect — Check.

4. Left engine — IDLE.

5. Right engine — IDLE.

6. OBC — Select.

7. MSL PREP — ON.

8. SW COOL — ON.

9. OBC — Deselect.

10. Hook operation — Check.

11. Takeoff Checklist.

12. Ordnance crew — Arm.

 

Seems like the ready 5 procedure included MSL PREP and SW COOL enabled on the deck before takeoff.

whats obc?

whats obc?

http://www.heatblur.se/F-14Manual/cockpit.html?highlight=obc#master-test-panel