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Old 10-09-2008, 12:39 PM   #1
scottysonfire
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Default What is "notching" ?

In air to air combat, Ironhand refers to "notching"

(http://flankertraining.com/ironhand/news.html)

Ive tried to run the track for his missile evasion tutorial, but it doesnt run properly, so Im just listening to his audio tracks and trying to visualise whats going on.

He mentions notching and I have no idea what it means.

any help would be appreciated
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Old 10-09-2008, 12:55 PM   #2
=RvE=Yoda
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Notching refers to going into your opponents doppler notch.

Essentially, radar uses multiple techniques to separate ground
clutter from true returns from the target, the primary method
being doppler shift separation.

By knowing what wavelength or frequency of the radar waves you
send out, you will be able to tell certain things.

Example if you send a "ping" of wavelength A on a target, the ping will return
a wavelength shorter than A if the target is moving towards you, while
the the ground returns a different wavelength.

So you could see the ground clutter is present as "blue color", while
the true target returns are "red". If the target moves closer and closer
to the same closure speed as the ground (that is perpendicular to the
radar beam direction) then the Red becomes more and more "blue",
and when he reaches close enough to the beam (also called the notch when
in look-down) the FCR is unable to tell the difference, and he notches you.
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Last edited by =RvE=Yoda; 10-09-2008 at 12:57 PM.
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Old 10-09-2008, 01:02 PM   #3
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Would notching be similar to beaming?

You have talked about the ground in your example - so Im assuming the notching technique youve described only works when you are lower than your oponent so he is looking down at you and the ground appears behind you?

So would I be correct in saying you try and keep him at your 3 or 9 o'clock position like in beaming but you are heading towards the ground or at a a lower altitude than him?

Do you "notch" before he launches a missile? Or do you notch after a missile is launched?
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Old 10-09-2008, 01:20 PM   #4
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Notching would be the same as beaming something, as long as
you are intentionally also attacking his radar notch - the
closure "band" where cannot separate ground returns from
true returns easily. (Yeah, in lockon this is just look-down)

Against Semiactives you can usually notch fairly easily even after
he launches. Against active missiles you should try to notch before the missile goes active.
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Old 10-09-2008, 01:32 PM   #5
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Notching is not the same as beaming. You beam to enter the notch, which is why people may confuse one for the other, but the notch specifically refers to the range of speeds around the ground-clutter closure that will cause a radar to drop your contact in a look-down situation (for example, your ground speed +/- 50kts).

Beam obviously refers to placing your bandit on your 3-9. They may look the same at first, but they aren't (a slow enough plane can notch without beaming).

You should notch whenever you feel it will do something for you - notching before the missile is launched is certainly valid, as is notching after a missile is launched. It all depends on the situation. In the case of LOMAC, notching before a missile is launched can work to confuse a human opponent, and to delay an AI opponent's launch (but AI are omniscient and will always shoot at you the moment you exit the notch )
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Old 10-09-2008, 01:45 PM   #6
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Yikes

It all sounds quite technical!

But surely if you go that slow (50kts) you will stall your aircraft? And even if you dont stall, you wont have much energy left for evasive or offensive flying if you survive his attack?

Another silly question: On the HUD in teh F-15, the numebrs on the left side of the HUD indicate airspeed? What are they set to? Miles per hour? Kilometers per Hour? Knots?

I find if I fly the F-15 below the number 200, it pretty much falls out th sky if you excecute high G turns

Is notching a high G manouvre?

sorry for the array of questions, I hope they all get answered
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Old 10-09-2008, 01:48 PM   #7
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50 kts closure more(or less) than the ground clutter could be what you need.
Not just 50 kts speed
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Old 10-09-2008, 02:31 PM   #8
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keh?
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Old 10-09-2008, 02:42 PM   #9
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Radar will dismiss/ drop/ filter out a contact that does not maintain a certain amount of measureable motion.

If a contact is closing on you at less than say.. the 50 knots in his example- it will often be dropped as a valid contact.
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Old 10-09-2008, 02:47 PM   #10
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Quote:
Originally Posted by scottysonfire View Post
Yikes

It all sounds quite technical!

But surely if you go that slow (50kts) you will stall your aircraft? And even if you dont stall, you wont have much energy left for evasive or offensive flying if you survive his attack?
You could still fly at 150 and just turn away a little, but you're correct in general.

Quote:
Another silly question: On the HUD in teh F-15, the numebrs on the left side of the HUD indicate airspeed? What are they set to? Miles per hour? Kilometers per Hour? Knots?
KCAS (Knots, Calibrated Air Speed)

Quote:
I find if I fly the F-15 below the number 200, it pretty much falls out th sky if you excecute high G turns
You can't execute high-g turns at anything resembling 200kts or less. Therefore, what shouldn't you do?

The F-15's preferred energy range in LO is between 350-475.

Quote:
Is notching a high G manouvre?
No. Notching has nothing to do with maneuvering, it is simply a range of velocities (specifically around closure of the ground clutter) that cause anything at those closures to not be displayed on your radar scope in a look-down situation.

You could use a high-g maneuver to get INTO the notch quickly (you want to get perpendicular to the radar beam ... ie beam the threat)
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