# Bullet proof protection? Do we need it?

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#### Mac790

##### Well-Known Member
I was cruising around the internet, and I've found a strange story at Vansairforce.net, it's about a guy whose plane had been a target for some dumb idio... He had a lot of luck a bullet missed his fuel tank by 6", and the pilot by 4'.
Full story here
Bullet Holes - VAF Forums

Seb

btw I was thinking about a few layers of Kevlar at the bottom of a plane many times, maybe it wasn't extremely silly idea.

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#### RonL

##### Well-Known Member
HBA Supporter
I used to have dreams of flying over the superstition mountains, with a backpack helicopter, those pictures are the very reason that dream faded into just something I would never really follow through with.:dis:

The idea of the backpack heli is still very much alive.:gig:

Ron

#### pepsi71ocean

##### Well-Known Member
you just need self seeling fuel tanks and some plate armor underneath the pilots seat, lol.

#### RonL

##### Well-Known Member
HBA Supporter
you just need self seeling fuel tanks and some plate armor underneath the pilots seat, lol.
Not sure if it was this forum (I think yes) a picture and article on how a bullet hit a rotor blade, the damage did not cause a crash, but the rotor had to be replaced.:mad2:

There are some heartless, crazy people down below.:nervous:

#### Mac790

##### Well-Known Member
... and some plate armor underneath the pilots seat, lol.
There is a link at vans for a nice Kevlar Ballistic Panels, I've read about 10-12 similar accidents, so it seems like there are more % down below.

Seb

#### Lucrum

##### Well-Known Member
Log Member
Too bad the FAA won't let us shoot back.

#### flyranch

##### Well-Known Member
I learned this while flying hot air balloons once, the instructor had gotten 'fired upon' many times:

The average hand held firearm (including rifles) cannot shoot vertically more than 2500 feet. There is just not enough energy in the round to make it that far. If you fly at least that high you should have no fear of ground fire.

The trouble is, most ultralight pilots like to stay around 1000 to 1500 agl.

There are exceptions, like the 50 cal., but not many people have those (wish I had one).

In the Air Force (in the early 70's), you could watch the infrared image of the rounds falling off as the enemy tried to shoot at the C-130 gunships.

#### Alan Waters

##### Well-Known Member
I believe the 2500 ft max range is incorrect. As a former 1,000 yard benchrest shooter I can assure you a bullet has no trouble going 3,000 feet horizontally. I know shooters who shoot 2,500 yards on occasionally.These are big 30 cal. rifles not 50 cal.

##### Well-Known Member
I believe the 2500 ft max range is incorrect. As a former 1,000 yard benchrest shooter I can assure you a bullet has no trouble going 3,000 feet horizontally. I know shooters who shoot 2,500 yards on occasionally.These are big 30 cal. rifles not 50 cal.
I would beg to differ as will many others. There is a huge difference between the force of air slowing something down, and the force of air AND gravity slowing something down. Gravity slows the bullet at 9.8 m/s2 or 32.2 ft/s2, add to that the air resistance and you have in excess of 1G force slowing the bullet down when shooting vertically. When the bullet is flying horizontal the gravitational force is acting at 90degrees to its flight path therefore not acting to slow it down (It actually speeds it up in a different direction). All that slows a horizontal bullet is air resistance (or a solid object it hits)

Shannon.

#### flyranch

##### Well-Known Member
It's a simple physics problem. Take the mass and initial velocity of a projectile going straight up and just plug the numbers into the formula (drag out the old physics books). Bullets can go a whole lot farther horizontally than vertically. If I get the time this evening (and if I can remember, old age is a pain sometimes), I'll see if I can do a 30-06 as an example.

#### Alan Waters

##### Well-Known Member
120 mm Gun M1 Anti-Aircraft Gun | World War II Database If I have made the metric conversion correctly this is what I see. A 50 pound projectile launched at 3000 feet per sec. going to an alltitude of 57,000 ft. Not hand held I admit but it makes me believe a 180 grain bullet at the same velocity would most likely make it to 8,000ft or so. Also a bullet never picks up speed after it leaves the muzzle. What would make it?

#### flyranch

##### Well-Known Member
AHHH! I may have to stand corrected on this :depressed

I quote from Yahoo

In 1920, the U.S. Army ran some experiments to try to understand how dangerous falling bullets were as they returned to earth. For their tests, they used .30 calibre, 150 gram, Spitzer-point bullets (this means nothing to me, but it might to you) that exited the gun barrel at 2,700 feet per second (about 3,000 km/h or 1850 mph). The Army estimated that the bullets, fired straight into the air, reached a height of 9,000 feet (about 2.7 km) in 18 seconds, then fell to earth in 31 seconds, for a total of 49 seconds in flight.
Terminal velocity ended up being about 300 feet/sec. So, it would appear that the info that my balloon instructor told me was not quite correct (at least for 30 caliber rifles).

#### bmcj

##### Well-Known Member
HBA Supporter
That sounds more likely to me. The high-end muzzle velocities (4-5,000 fps) would climb over 30,000 feet if gravity were the only player, but you also have to take into account normal drag and mach drag and the effects on drag if the bullet tumbles. 9,000 feet sounds like a realistic estimate.

Bruce

#### Dana

##### Super Moderator
Staff member
There was a thing a couple of years back. A guy in [IIRC] Kansas liked taking potshots at powered parachutes (PPC's) flying over his land. This was especially a problem as once a year a major PPC fly-in was held in the area. Fortunately nobody was hurt, but quite a few PPC's came back with holes. He was caught, found gulty, and sentenced to probation... and jail for one week each year for some number of years... the week of the annual fly-in. :gig:

-Dana

People are more violently opposed to fur than leather because it's safer to harass rich women than motorcycle gangs.

#### lr27

##### Well-Known Member
The gravity is insignificant compared to the air drag. Neglecting compressibility (Mach) effects, a bullet with a terminal velocity of 300 fps that was fired at 2700 fps would have an initial deceleration of about 80 g's. That's enough to take off ALL the velocity in a little over a second, but of course the resistance goes down as it slows down.

Probably 90 percent of the energy is gone in 2,000 or 3,000 feet, though I think you'd want at least 99 percent gone!

I ran a spreadsheet which seemed to suggest that it wouldn't get even as high as 9,000 feet, though perhaps there are some other factors going on.

#### Mac790

##### Well-Known Member
The range is one thing, but I don't it's easy to hit a plane at 2500-3000ft.

Seb

#### DarylP

##### Well-Known Member
During bird hunting I stayed at 1000 feet, as the shotgun pellets would not go that high. But during deer hunting, I stayed as far away from the favorite tree stands. Unless it was bow season. :roll:

#### Waiter

##### Well-Known Member
10 - 15 years ago, there was a NOTAM warning low flying aircraft to avoid areas around Bonny Doon, Felton, and Ben Lomand Calif. Seems there was a farmer out there who didn't take kindly to airplanes out there spying on his cash crop, and numerious aircraft reported bullet holes in their planes after flying through the area!

Waiter