The AH-64 Apache

[Kyle Harmse]

Hey gents,

I have a question on this terrifying machine :-P Especially pertaining to its Target Acquisition and Designation System, and how that stacks up to the optics of the time of its introduction (circa 1985)...

1) What sort of zoom levels was it capable of?

I've read on the British army website that the TADS mounted on Longbows prior to their upgrade to the Arrowhead system had a 16x optical channel, a 32x (!!!) thermal imaging channel, and up to 150x TV zoom. Is this indicative of the abilities of the AH-64A circa 1985? It would certainly put it in a league above in terms of target acquisition

Any documents or links would be highly appreciated

[AlphaOneSix]

Note that the first unit to get Apaches got them in the middle of 1986, and the earliest they could likely be considered "combat ready" in any capacity was probably early-1987.

Anyway, the field of view data from the A-model Operator's Manual is listed in degrees, not in magnification factor, so good luck converting that. I'm sure someone here knows how to do the conversion...

Here is the FoV data (which would be valid for a late-eighties AH-64A):

Direct View Optics (DVO):

Wide: 18.0 degrees

Narrow: 4.0 degrees

Day TV (DTV):

Wide: 4.0 degrees

Narrow: 0.9 degrees

Zoom: 0.45 degrees

FLIR:

Wide: 50.0 degrees

Medium: 10.0 degrees

Narrow: 3.1 degrees

Zoom: 1.6 degrees

EDIT: This data is in diagonal FoV, not horizontal.

[Invader ZIM]

This may not be quite what your looking for, but the info contained shows the challenges of using even the optical systems of the Apache to do it's job.

http://trace.tennessee.edu/cgi/viewcontent.cgi?article=3028&context=utk_gradthes

And a cool video of a 1991 Apache using the image intensified/thermal site to hit Iraqi armor.

[Kyle Harmse]

Note that the first unit to get Apaches got them in the middle of 1986, and the earliest they could likely be considered "combat ready" in any capacity was probably early-1987.

Anyway, the field of view data from the A-model Operator's Manual is listed in degrees, not in magnification factor, so good luck converting that. I'm sure someone here knows how to do the conversion...

Here is the FoV data (which would be valid for a late-eighties AH-64A):

Direct View Optics (DVO):

Wide: 18.0 degrees

Narrow: 4.0 degrees

Day TV (DTV):

Wide: 4.0 degrees

Narrow: 0.9 degrees

Zoom: 0.45 degrees

FLIR:

Wide: 50.0 degrees

Medium: 10.0 degrees

Narrow: 3.1 degrees

Zoom: 1.6 degrees

EDIT: This data is in diagonal FoV, not horizontal.

Thanks Alpha, I've seen this somewhere before as well (FAS probably). Problem is, without knowing the focal length of the optical lens, there's no sure fire way of converting FOV into zoom factor that I'm aware of (though the two are directly related)

This may not be quite what your looking for, but the info contained shows the challenges of using even the optical systems of the Apache to do it's job.

http://trace.tennessee.edu/cgi/viewcontent.cgi?article=3028&context=utk_gradthes

And a cool video of a 1991 Apache using the image intensified/thermal site to hit Iraqi armor.

Thanks Zim I have a similar document relating to the management of the system during its development cycle as well. No technical data though

[Invader ZIM]

This link shows the magnification for the UK MoD AH MK1 before the upgrade to the newer optical systems.

http://www.armedforces.co.uk/army/listings/l0054.html

Apart from the ‘Longbow’ mast-mounted fire control radar, the aircraft is equipped with a 127 x magnification TV system, 36 x magnification thermal imaging, and 18 x magnification direct view optics.

The night vision system of 67 Apache AH Mk1 attack helicopters is to be upgraded. The M-TADS/PNVS, which is designated Arrowhead, is replacing the existing forward-looking infra-red (FLIR) and daylight television image intensifier with new sensors to provide improved target identification over longer ranges, better pilot performance and reduced life-cycle costs.

[Kyle Harmse]

This link shows the magnification for the UK MoD AH MK1 before the upgrade to the newer optical systems.

Quote:

Apart from the ‘Longbow’ mast-mounted fire control radar, the aircraft is equipped with a 127 x magnification TV system, 36 x magnification thermal imaging, and 18 x magnification direct view optics.

That indeed was the source I half remembered

Looking at the TADS' physical dimensions, its likely that it has a lens focal length of about 600mm, given size and weight limitations- which is actually very similar to what the Leo and Abrams optical scopes are.

EDIT: That is, the optical channel for such a ginormous scope has a zoom of around 17-18X, which gels nicely with the direct view optics quote from above

Where the system is really great, I think, is in the level of resolution they squeeze out of it with TV and FLIR modes. Digital enhancement is how I'd wager the Longbow gets so much zoom. I'm not entirely sure the AH-64A would have had so much imaging processing power though. I do know TADS has been improved multiple times in its lifetime, up to the new super high resolution Arrowhead system.