How to Hit Targets With Unguided Bombs

[mdmckeever 0]

I'm taking physics in my senior year of high school now and we're on trajectories. I threw this equation into SFP1 and it worked well. If you want to drop bombs the old fashion way, here is how to solve it.

 

Note:

-Wind resistance is not a factor

-For this to work, you have to put SFP1 in METRIC. The gravity equation I have works in METRIC only.

 

1. Take your altitude and multiply it by 2. Then divide that by 9.81. Then do the square root of that number. It'll give you the amount of time it takes for the bomb to hit the ground.

 

2. Calculate your speed in meters per second. To do so, take your kph and multiply it by 1000, then divide that new number by 3600.

 

3. Take your distance from the waypoint (IN METERS) directly above the target and divide it by your speed in m/s to get the time it will take for you to get to the waypoint.

 

4. Subtract the amount of time it takes for the bomb to hit the ground from step 1. Then, multiply it by your speed again.

 

5. The new number you get should be how far you must travel to get to the dropping point, subtract the distance you are from the waypoint by the new number. That will give you how far you must be from the waypoint to drop the bomb.

 

6. If it makes you feel better, divide it by 1000 to get it in Kilometers.

 

Here's an example:

Altitude: 3000 m Waypoint = 42 KM

Velocity: 850 kph

 

1. 3000x2= 6000

6000/9.81 = 611.62

\/611.62 = 24.73 seconds

 

2. 850x1000 = 850,000

850,000/3600 = 236.11 m/s

 

3. 42x1000 = 42,000 meters

42,000/236.11 = 177.88 seconds away from waypoint

 

4. 177.88 - 24.73 = 153.15 seconds until you can drop the bomb

 

5. 153.15 x 236.11 = 36,160.25 meters until you can drop the bomb

42,000 - 36,160.25 = 5,839.75 Meters from the waypoint

 

6. 5,839.75 / 1000 = 5.84 Kilometers away from waypoint.

 

Hope this helps anyone. Good luck and good hunting. =]

guidance.bmp

[gbnavy61 1]

I would assume even with all this math stuff you'd need to be pretty much right on parameters and right on course to get even close to the target.

 

What kind of targets are you going up against and what kind of ordnance are you using? Also, how are you determining when you're at your drop point in the game? Also, how do you identify your other parameters - altitude is obvious, but not all aircraft have True Airspeed gauges - and what about different units like knots and feet vice meters and kph?

 

Not trying to shoot down your work here - it's a good application of what you've learned in class - but, it seems an awful lot of effort to plan out the drop. If this is a WWII type bomb run with about a dozen or so 500lb bombs with a large target, this would work well. But otherwise, it seems like it would lack the precision needed to hit smaller targets, when a little dive-bombing might get you a whole lot closer, without all the number-crunching.

Edited November 11, 2008 by gbnavy61

[mdmckeever 0]

This is a theoretical situation. This isn't referring to real life situations where wind resistance would be a factor as well as some other factors. This is the Strike Fighters Project 1 simulator, which is a theoretical simulator, not a real one. As far as Wings over Vietnam, Wings of Israel and the other simulators, I don't know because I haven't used this equation in them yet. If anyone would like to tell me how well it works, it would be appreciated. I understand that you're not trying to shoot me down and I'm going to answer your questions.

 

I am talking about static targets, when it comes down to mobile targets such as ships or vehicles, if you have the same heading as them, add their velocity to your velocity, if they're heading is 180° difference, subtract their velocity from your velocity. This is a theoretical situation.

 

The simulator includes an option in the Options menu to select the units you are using as mentioned before, I stated to convert your units to metric.

 

The simulator provides an exact definition of your altitude, velocity, and distance from the waypoint which is located directly above the target as far as the simulator goes, located in the top left corner of the screen. I understand that in reality, it would be a whole lot different. This is a theoretical situation.

 

As far as getting closer, I wouldn't want to risk my neck if there's a lot of AA down there. It's not worth risking your life for. This if for the people who are interested in hitting their targets without leaving their comfort zone in the sky. I also understand that there are LGB and LGRs. This isn't for those types, they guide themselves.

 

"If in other sciences, we should arrive at certainty without doubt and truth without error, it behooves us to place the foundations of knowledge in mathematics." - Roger Bacon

[gbnavy61 1]

I know it's theoretical and all for fun within the game. I'm just suggesting that this technique of determining the drop point may not give the accuracy necessary to hit/destroy your target every time (again, unless we're flying a B-17 w/ a dozen bombs, or using cluster bombs).

 

I didn't remember if the sim allowed everything to go into metric. Anyway, that still leaves two problems. First, airspeed. I'm pretty sure that the default info in the lower left corner gives you Indicated Airspeed (same as on the instrument panel). Is there a way to get True Airspeed? In the end TAS is what you need to base your calculations on, because the higher you go the more difference there is between IAS and TAS - kinda makes a difference if you want to be up higher to avoid AAA. If you have no wind, TAS is your Groundspeed - i.e. how fast your jet, and consequnetly, the bomb, is moving over the ground. Second issue is altitude. Just because you are at 6000' on the altimeter, doesn't mean you have 6000' between you and the surface. So, some advanced knowledge of the target elevation is required for accuracy.

 

I tried this out in WOI yesterday - took a Scooter over to hit a runway. I ran the numbers for 300kts at 6000ft and got a drop point of 1.6NM. I know you used metric numbers, I converted to English units. Now, I have my targeting and HUD set to 'hard' so I wasn't able to be extremely precise with the drop point, but I got pretty close to the drop point (by eyeball anyhow). I came in at an angle because flying down the length would kinda defeat the purpose of the test. My bombs missed a runway-sized target by a good 100' laterally at least (assuming runway centerline was the desired impact point).

 

Now granted I wasn't perfectly on parameters, but that's kinda the point - is anyone ever going to be exactly on? If you're off a couple feet on altitude, or you're a couple knots fast or slow, or you're slightly offset to one side of the other, it can make a big difference. The higher you are, the more flight time the bomb has, which means any deviations from your drop parameters have that much more time to affect the impact point. And if you're off on more than one parameter the affect could be increased (for example, if you're higher and faster than your drop numbers - your bomb is going to overshoot the target quite a bit).

[macelena 1,070]

I use the LeMay/Harris method : drop a lot of bombs

 

 

LET THE BOMBS HIT THE FLOOR

 

EDIT: Seriously, a shallow dive could work with light fighter-bomber

Edited November 11, 2008 by macelena

[+malibu43 142]

A couple things:

 

1. One of the most important things is that you stated wind resistance isn't factored in (which is good that you stated your assumptions). However, wind resistance is factored in in this game. Well... not technically wind resistance, but air resistance. The weapons have drag factors, and drag is never considered in basic physics trajectories, and not in you equation either. So, the higher you get, the more off you're going to be. Different weapons have different drag coefficients, so it's going to be a different offsets for all altitudes and weapons.

 

2. I know someone else already kind of said this, but using the techniques they used in real life (low altitude, low level, a-la A-6A, or dive bomging, a-la F-105) provided better results in real life and I think provides better results in terms of this simulation as well.

 

I think your equation would be appropriate if you're using something like a nuke, and you can work weapon drag into the equation.

 

But good for you for trying to apply these physics equations. I haven't used any of those equations since I watched the video where the Cesna drops the orange ball into the water...

[Lexx_Luthor 57]

Man this is great stuff. Yep, this is best for nucs or lots of regular bombs.

 

For air drag, you might could setup drop tests that you can read off the distance to impact...Setup a strike with the weapon, altitude, and *airspeed* you wish to use -- and use consistently.

 

Drop anywhere -- but assume target is sea level -- on the map, and record the drop coordinates from the FULL debug data display, then use Weapon View to record the impact coordinate, wherever that might be. Use the x,y coordinates ONLY to get the horizontal distance between the two positions. That's your drop distance from target.

 

This should work, unless I'm missing something (usually the case).

 

This will change if target is significantly higher than sea level, requiring further tests.

 

Instead of relying on a distance to target indicator, one could use a bomb sight. I usually just use an enlarged gunsight highly depressed. Another thing talked about here was drawing on the radar.bmp some bomb drop indicators, to drop bombs using the ground mapping radar as a form of all weather day/night bombsight -- works above clouds and at night.

 

This was new to me: Did you know that the Canberra bombers were primarily "built" for high altitude visual bombing...above 40,000 feet! The series never got bombing radars in sufficient numbers, so they added a bombadier with glass nose. Good read ~> http://www.vectorsite.net/avcanbra.html

[Lt. James Cater 62]

The only time i have ever done level bombing was in an F4 at low altitude, high speed, in lousy weather, and while being shot at.

 

Damn right i missed!

[Wolf65 0]

The only time i have ever done level bombing was in an F4 at low altitude, high speed, in lousy weather, and while being shot at.

 

Damn right i missed!

That's my favorite way.

[+Muesli 2,161]

In the KMD mission editor there is a sort of calculator which

roughly tells you when to drop which bomb. Depending on altitude,

speed and bombing angle.

 

Hope it helps, it is simple and not accurate, but it calculates better

than the grey matter which seems to be in my nugget!

 

 

Cheers!

[Lt. James Cater 62]

That's my favorite way.

 

Give me halfway decent weather, a Thud hauling a standard load and there'll be no need for level bombing.

[+Muesli 2,161]

This might help (a little)!

[DWCAce 19]

Be sure to check out this tutorials as well (it's a must read)

 

http://www.simhq.com/_air/air_055a.html

[Lt. James Cater 62]

Be sure to check out this tutorials as well (it's a must read)

 

http://www.simhq.com/_air/air_055a.html

 

My big disagreement with the tutorial is the pulling back of the throttle.

 

About the lowest i've ever had the power is maybe 25% in a area that was milk run heaven. Up in pack 5 and 6 you can best believe that you will want to be going as fast as you can over the target. Full military power in the dive also will give your ordnance a better trajectory as well as letting you get the hell out of there that much quicker.

[FastCargo 412]

The article was written by an actual fighter pilot who dropped those kind of weapons from that kind of aircraft. As a former mud mover myself, I think I'll take his advice.

 

FastCargo

[+malibu43 142]

The article was written by an actual fighter pilot who dropped those kind of weapons from that kind of aircraft. As a former mud mover myself, I think I'll take his advice.

 

FastCargo

 

 

Oh snap!

[Lt. James Cater 62]

Granted this is a sim and i was but an earth bound Armor crewman, In Ed Rasmius's book he heard a distress call from an F4 that chopped it's throttles during the bomb run and the engines cut out.

 

Rasmius wondered why ANYONE would do something like that over a target area.

[FastCargo 412]

...chopped it's throttles...

 

Which is not the same as putting your throttles to idle.

 

One can be considered throttle bursting, which can cause compressor stalls and flameouts.

 

The other is used to control your airspeed, critical in making consistent bomb deliveries.

 

Personally, I don't give a rat's ass how you make your weapon drops as long as they work...in the sim.

 

It's a different thing altogether if come screaming across at mach snot, only to splatter yourself into a hill, or pull out too soon and don't get close enough to ensure a good drop, or try to threat manuver and realize you don't have enough nose track because you're way above corner speed or you over G or black yourself out trying to make that nose track.

 

FastCargo

[Lt. James Cater 62]

Ok, i see your point.

 

Personally, i never had much of a problem dive bombing since i've been reading about it since i was in elementary school. Excepting a few times, i try to keep things as much as what i researched about F-105 pilots in action throughout the years.

[+Typhoid 231]

Which is not the same as putting your throttles to idle.

 

One can be considered throttle bursting, which can cause compressor stalls and flameouts.

 

The other is used to control your airspeed, critical in making consistent bomb deliveries.

 

Personally, I don't give a rat's ass how you make your weapon drops as long as they work...in the sim.

 

It's a different thing altogether if come screaming across at mach snot, only to splatter yourself into a hill, or pull out too soon and don't get close enough to ensure a good drop, or try to threat manuver and realize you don't have enough nose track because you're way above corner speed or you over G or black yourself out trying to make that nose track.

 

FastCargo

 

yup.

 

similar thing happens to engines in the carrier environment as the comment above about chopping ones throttle and having the fan quit. "Retarding the throttle to idle" is not the same thing as ham-handing the throttles around and inducing a flame out and/or compressor stall.

 

short sea story of an E-2 pilot doing initial Carrier Qual (CQ) and ham-handing the throttles around. the IP "counseled" the student several times about judicious movement of the throttles but without success in getting his full attention. Then on a touch and go (or what the pale blue suit guys accuse us of "crash and dash") the student rammed the throttles from full idle to full go on touch down and promptly induced a dual engine compressor stall while rocketing down the angle........

 

lots of excitement in the cockpit and tower..........

 

the IP got one of them restarted as they went off the angle and they didn't get too damp from the sea spray as they bottomed out on one fan. Their flightsuits were a little damp and sticky though........

 

end of instructional flight.........

 

similar happened to me with a student in a general aviation doing a practice precautionary approach. On the go around he jammed it forward and it quit. I just gently brought it back and then back up and away we went. Point being that in the real world, jamming the throttles around can result in a bit of sweat in the cockpit at inconvenient moments.

[Lexx_Luthor 57]

Other than FB/PB, has throttle jamming ever been modelled in the Sims? I enjoyted the challenge in Oleg's sim is stuff like -262 and YP-80 where you have to be very gentle with the throttles, at least at the low end.

[mdmckeever 0]

In IL-2 Forgotten Battles, if you throttle jam with the Me-262, the engines catch on fire, but not really stall. Is that a realistic interpretation of what would happen or would it just stall? I think the reason the engines caught on fire was the rapid increase in thrust with the afterburners caused it to ignite.

[FastCargo 412]

Well, it depends on the engine and reason for the compressor stall.

 

Here is a pretty concise definition:

 

http://en.wikipedia.org/wiki/Compressor_stall

 

Basically, I've seen everything from just a slight buzzing with an engine not running at full capacity to full blown banging with flames shooting out. I've never seen an engine blow up directly due to a compressor stall...usually if that happens, it's because something else was already present.

 

From what I can tell, the TW sims don't model this.

 

FastCargo

[yubba 70]

well lets get this up front