Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!apple!veritas!amdcad!amdcad!military From: glo@Eng.Sun.COM (Gary Owens) Newsgroups: sci.military Subject: Re: Bombers over the Falklands (was Re: B52 Replacement) Summary: lofting is an oldie but goodie Keywords: laser-guided bombing loft Message-ID: <1991Mar23.061800.5327@amd.com> Date: 23 Mar 91 06:18:00 GMT References: <1991Mar12.225105.25754@cbnews.att.com> <1991Mar20.035047.2613@cbnews.att.com> <1991Mar22.042833.21632@cbnews.att.com> Sender: cdr@amd.com (Carl Rigney) Organization: Sun Microsystems, Mt. View, Ca. Lines: 97 Approved: military@amd.com From: glo@Eng.Sun.COM (Gary Owens) In article <1991Mar22.042833.21632@cbnews.att.com> consp04@bingsuns.cc.binghamton.edu (Dan Boyd) writes: > >In article <1991Mar20.035047.2613@cbnews.att.com>, >vexpert!mst@relay.EU.net (Markus Stumptner) writes: >|> It is a wonder they hit the runway at all. [...] The pilot then >|> started a climb and the bombs were released on an ascending >|> trajectory with the plane still 3 miles away from the coast. > > Tossing iron bombs around this way would not be accurate >enough. This means to me that they were using laser-guided bombs and >had someone (SAS commandos, perhaps) on the ground with a designator. > Otherwise, this was quite a tricky piece of flying. Not extraordinarily tricky - on several "older" generation planes (A4 and the like) their bombing computers (haven't seen the newer generation planes cockpits that close) have modes for (among other things) "loft" and "over the shoulder". What was described above is "loft", where the pilot pulls up (at the right time/rate) before reaching the target to establish vertical momentum and the bombs are released at the right moment that causes them to follow a trajectory that will hit the target. The advantage is that you don't have to overfly the target, though the increased flight path of the bombs causes more wind/ aerodynamic drift of the bombs. Think of "loft" as an underhand pitch or lob. (some pictures - limited by ascii resolution) plane turns aside --\ o X - bomb "lofts" up and then down. . X X plane approaches .rX-release X & pulls up --\ . X ..>........... . X ---------------------------------- TARGET ------------ |<------ D ------>| "D" is calculated by the bombing computer based on aerodynamics of bomb, aircraft speed/altitude, G's, position of aircraft & target, etc. For some real rough back of the envelope calculations: A 10000 feet per minute climb is pretty easy from down low, which is 166 feet per second vertical speed. Say 500 mph horizontal - 733 fps. Add these two vectors together gets you 751 fps - not exactly a stellar "muzzle velocity", but you're starting high in the air (for an elevation advantage and lower air resistance) and the bomb has a low drag compared to bullets. Or grenades - the MK 19 grenade machine gun posting listed it at 790 fps with range of 2200 meters (1.4 miles). "Over the shoulder" is to fly over the target, pull up at the right time so you eventually are near/actually inverted flying back toward over the target. The bombs were release by your trusty bombing computer sometime after you're past the vertical, so they fly up and then "backwards" (hence "over the shoulder") and down onto the target. More accurate (since you "mark" when you actually cross over the target so the computer has a more precise fix), but unhealthy if the target is shooting back fiercely. You do get the advantage of coming in low and fairly fast to identify the target, and afterwords being high (lots of kinetic energy) and inverted so you can see what is coming back at you and can dodge it while you get the **** out of there. X bomb goes up... then must come down X X finally, get away! < ............X . X X r - "bombs away" X . X . X . pull up fly in low X . .......................>..............M..... fly over, tell computer "mark" ---------------------------------- TARGET ------------ It isn't pinpoint accuracy like laser/IR guided weapons, but given good wind data, bomb weights, etc., not much less accurate than a plain drop. It is also far easier to achieve surprise by lofting or over-the-shoulder than by dive bombing, even though accuracy suffers. This isn't rocket science (bombs "fly" unpowered ;-), just simple ballistics and aerodynamics. Given a couple of racks of bombs, I can see how some would end up on the runway if that was the target. CEP is on the order of several hundred feet best case - not enough for a tank or hard bunker, but hell on runways. CEP - circular error of probability - diameter of the area within which the odds are the bomb/shell/missile/... will hit. -- Gary Owens glo@Eng.sun.com 415-336-9152 Sun Microsystems, Desktop Systems Software