The bombing and the wind

[rammjaeger]

I know German WWI-bomber used devices to measure the influence of altitude and speed for the aiming against enemy targets.
There was often reported the influence of the wind was "big" and not in consideration. I have no idea about the real influence of wind on the results of bombing.

What happens if a bomber is flying 120 kmh in 2000 meters and is dropping a 25 kg-bomb if the wind is coming with 10 meters/second from top (or the right side/or the left side or the back)? What happens if the bomb has a weight of (only) 5 kg or 100 kg or more?

I am just curious. Maybe anybody knows an own example for the influence of the wind on bombing attacks?

[Dan_San_Abbott]

rammjaeger:
The track of the bomb will be affected by wind, without a doubt. If the aiming sight cannot compensate for the effect of wind, the bomb will not hit the target. Hitting the target in WW1 was more luck, than skill and effective bomb sights.
Blue skies,
Dan-San

[Barrett]

Apart from wind and other atmospheric factors (temperature, humidity, etc) there are inherent errors in every perfectly-aimed "dumb" bomb. As I recall, even streamlined Mk 80 series ordnance of recent years has a built-in potential error of as much as six mils 6 ft at 1,000 feet). Soooo...a perfectly-aimed Mk 81 ferinstance might still strike 90 feet from the aimpoint if dropped from 15,000 feet. I have no idea what the mil error for WW I ordnance may have been, but obviously it was considerable. OTOH, it was usually released from fairly low altitude.

[Boom]

Yep, what Barrett says. Even with vaunted Norden sight USAAF bombing had a terrible accuracy. Simply too many variables.

If you want to get a feel for what it was like in Great War conditions go to a Fly-in where they have a Flour Bombing contest and get someone to take you up in a Piper, Cessna, etc. and give it a try. Deucedly difficult, what?

cheers, Boom

[rammjaeger]

Many thanks for the replies!
Especially the example with the Mk 81 is very instructive.

I am still wondering that German bombers killed and wounded a relatively high percentage of British military personal (22% military, rest civil) if attacking London in WWI - especially if we consider the high altitude of bomb releasing. At least I can not imagine a low level attack against London.

VBR
Rammjaeger

[Barrett]

Rammjaeger raises a really interesting point: a lowl-level against London in 1917 or so. Actually, it might have worked extremely well. (At least once.) I don't know the usual Gotha bombing altitude but doubt that the Brits had suitable AA armament in the numbers necessary to counter a blitz against a specific target from, say, 2500 feet agl. It'd keep 'em out of the worst of the smallarms and practically immune to the bursting stuff (poor horizontal visibility in urban areas and fear of "friendly fire" casualties.) Low-level at night would also be an option.
Hoo-ee! Spool up Wagner on the Victrola!

[rammjaeger]

Oh Barrett,

now I recall an illustration of a German night bomber attack against a British port. On this pic the bombers were shown in a very low flight. Maybe I can find the picture and the article describing the action again ... but that will last a while.

VBR
Rammjaeger

[stevedrew]

All,
In my last job, I was a weapons analyst for the Australian Navy. I was at first trained in underwater weapons, and anti-submarine torpedoes were my speciality. Then I was trained in Naval gunnery. The multitude of things that affect the ballistic trajectory of a projectile through the air are way too numerous to mention here, and can EASILY fill a shelf of your bookcase.

Steve

I guess bombing goes something like this:You aim against the wind onto your target[calculating how much side off you need!],at the same time you calculate how much lead you need to ensure the bomb hits the target[I think the trajectory for a 25kg bomb is different to that of a 250 kg bomb and to hell with physics!!]and at the end you are just gratefull for GRAVITY

[Barrett]

Within certain broad limits, the ballistics of a "shape" are similar regardless of size. Hence the Mk 80 series of weapons (developed in part by Ed Heinemann of Douglas fame). the mixture of ordnance in the early 60s was such that big & small, fat & skinny (relatively speaking) shapes needed their own particular ballistics settings dialed into the sight/scope in the form of mil values. With Mk 81s to 84s, there were similar values regardless of size & weight--though of course heavier projectiles are less effected by wind.
For biplane/lightplane bombing, the "one potato, two potato" method works reasonably well, given consistent weight and shape of the "ordance." (Paper bags with flour are notoriously inaccurate.)