Hi-lo-hi Profile. What?

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Member for

15 years 3 months

Posts: 499

I've heard the term used in regards to aircraft sorties before. Hi-hi-hi profile, lo-hi-lo profile, etc.

What does it mean? :confused:

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Member for

14 years 11 months

Posts: 76

Those are bombing (strike) profiles for aircraft. See this picture I got from glob@lsecurity:

http://i266.photobucket.com/albums/ii249/ikkezzzzz/image1288.gif

The profile chosen has implications for fuel consumption and therefore range.

hi-hi-hi is missing in the picture, but I guess now you can draw that one yourself.

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15 years

Posts: 776

this is a rather cool profile i found while google image searching 'mission profiles'

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14 years 7 months

Posts: 178

Can anyone give examples of aircrafts' ranges in hi-lo-hi or lo-lo-lo or lo-lo-hi?

Member for

23 years 1 month

Posts: 7,989

Well, it's hard to find accurate figures, but I'm sure google is a decent place to start.

The bottom line is that the more time an aircraft spends at low altitude, the shorter its range is. A hi-hi-hi profile gives you the most range, but it also makes you vulnerable to modern air defenses for a much longer period of time. By contrast a lo-lo-lo profile allows more time "under the radar", but significantly increases fuel consumption, thus reducing your range.

Member for

23 years 1 month

Posts: 11,742

Some data for the Su-27SK with Tf engine
Maximum flight range
(with rockets 2xR-27R1, 2xR-73E launched at half distance):
- at sea level, km 1,340 (lo-lo-lo)
- at height, km 3,530 (hi-hi-hi)
and all the other combinations are between.

Some data for the Su-25K with Tj engine
Practical flight range without external ordnance and stores, km:
- at sea level, km 500
- at height, km 1,000

Member for

18 years 7 months

Posts: 547

According to WarbirdTech Series MiG-29 and MiG-21 by Yefim Gordon and Peter Davidson, combat radius for F-16, MiG-29 and MiG-21 for hi-lo-hi mission profiles are:

F-16C; w/ 2 x 900kg bombs, 2 x AIM-9: 1,200km (same config but lo-lo-lo: 740km)

MiG-29; w/ 2 x 900kg bombs, 2 x R-60: 500km (same config but lo-lo-lo: 315km)

MiG-21MF:
w/ 4 x 250kg bombs, internal fuel: 370km
w/ 2 x 250kg bombs plus drop tanks: 740km

Member for

17 years 5 months

Posts: 3,718

A fairly often quoted mission is the "hi-lo-lo-hi" profile. That puts the emphasis on a low level dash into target after the high cruise in.

A normal hi-lo-hi more or less assumes a descent into target (while descent is often not regarded in mission fuel considerations), a combat fuel allowance at target altitude (the "lo"-part) and then climb and cruise back.

A hi-lo-lo-hi will see the aircraft descent, fly a certain distance (30, 50, 100 nm) into target area, waste some fuel and especially bombs there and then egress at low altitude for a bit smaller distance. This profile is the typical for long/medium range attackers like Tornado, F-111, Su-24.

On many occasions the air defences at medium altitude were actually worse than on lower altitude (for example Kosovo 1999), due to good ECM and SEAD tactics. Then aircraft fly hi-med-hi, means, they don't descent to the deck at target. For smartbombs an attack on the deck is not necessary any more, a GPS bomb is best released at 30000ft.