Fighters and icing condition

[LearjetGA]

Hi,

I was wondering: Are fighters provided with anti-ice systems, de-ice, anything at all ?

Fly safe

LearjetGA

 

[jetdriven]

i work with an F-15 pilot and he said no. The F-15 does not have heated wings or tail but they scrubbed the mission if the wx was bad. (icing or low IFR) Above 275-300 KIAS ice would not form anyway because of aerodynamic heating.

 

[Toro]

Originally posted by LearjetGA
I was wondering: Are fighters provided with anti-ice systems, de-ice, anything at all ?

Eagles don't have a de-ice system (heated wings or tail), but they do have an anti-ice system for the engines. If we're about to enter known or suspected areas of icing, we flip an engine heat switch that works to prevent ice buildup in the inlets.

Originally posted by jetdriven
i work with an F-15 pilot and he said no...they scrubbed the mission if the wx was bad. (icing or low IFR)

Wha? Either you misunderstood him or he didn't know what he was talking about. The weather would have to be absolute dog$hit to scrub a mission. We will take off as long as the weather is above pilot minimums (which for most pilots is approach minimums ~ 200 feet). Icing, while not smart to fly in, does not specifically prohibit us from flying.

Above 275-300 KIAS ice would not form anyway because of aerodynamic heating.

You are completely out to lunch here - I've had icing on the jet at much faster airspeeds than this. In fact, the only time we even fly below 300 knots is when we're slowing to land. It's not like we're the space shuttle on re-entry; airspeed isn't going to affect aerodynamic heating of our jet.

 

[LearjetGA]

Thanks for the quick response.

I am pretty surprised that you don't have much to protect yourself from ice. What if you are carrying external loads ? That must be an ice magnet.

 

[JCJ]

cool reading

for those of us who won't ever actually fly a pointy-nose, Schiffer Military History Books has published (with USN approval) a complete reproduction of the navy F4-J NATOPS Flight Manual. It's very nicely done (ISBN 0-88740-781-1) and costs about $40.00

according th that manual, the F4J is equipped with bleed air engine anti ice to be used in suspected icing conditions at subsonic speeds, but only to be used during actual icing conditions at supersonic speeds

 

[Eagleflip]

You have to remember that all military fighters fly far above the normal icing levels for the vast majority of their missions. Yes, external stores will collect more ice than a clean wing, but the total time of exposure at icing levels is significantly less than a piston twin/single out there flying in the middle of the muck.

The good news for the fighter dude/dudette? You normally have enough excess power to get yourself out of those conditions before you get into trouble.

Ref. the airspeed/aerodynamic heating issue, there is an Air Force meterological document (I will look it up and edit this response when I find it) that specifically states that at airspeeds above 350-400 kts, aero heating will preclude ice formation. I don't believe it, though. It doesn't pass the common sense check.

The best comment I ever heard about icing came from Flying magazine, specifically "Whenever you attempt to fly an airplane with ice on the wings, you are in effect a test pilot."

 

[Snoopy58]

Below -40 degrees (C) SAT (i.e. ambient temperature), it is apparently too cold for ice to form -- at least, we can turn off the engine anti-ice in a 737 when it is colder than that. That happens somewhere around FL 310, plus or minus, iirc. So above that altitude (whatever it happens to be, where you are, today), no worries. Below that, ice MIGHT form, if your TAT (i.e. aerodynamic heating included) is cold enough (like, freezing or below). TAT goes up with airspeed & also with ambient temperature; it is possible to fly "fast enough" to keep TAT warm enough (we use +10 TAT, to allow a margin of safety & for whatever effects happen to the air as it enters the engine) that you don't need the anti ice. "How fast" that would be is obviously dependent on multiple factors.

Somebody smarter than I am could run the numbers on airpspeed & altitude & tell you what combinations would protect you completely from ice, but there are a couple of different ways that it can become no factor.

Perhaps speeds above the 350-400 kts generates enough aerodynamic heating that the only way you can get a TAT below zero is to start with a SAT below -40... i.e. by the time your WING is cold enough for ice to form, the AIR is too cold to cause you any trouble. But that's a guess... I don't have any numbers I could check that theory with. But it could explain the statement in Eagleflip's weather handbook, if my guess is correct.

Snoopy

 

[LearjetGA]

Well, about the aerodynamic heating, this is an example i remember:
On the Fokker 50, at 15000, cruising at 250 TAS, the nose will be exposed to the normal friction and would 16 degrees C warmer than the rest of the fuselage.

Just a thought