helicopter v/s bottle rocket

[gezzer]

The charge said INTO an Aircraft. She is great!!!!! hit a chopper with a bottle rocket what a shot!! Also he must have been way below FAA regs for a bottle rocket to reach it. Can we say pilot loosing license? I doubt the da will continue the charge. This looks like a case of taking them for the ride or what can be called Malicious prosecution.

Pardon the typo's my arthitus is acting up and the firngers are not hitting the right keys.

 

[DoubleTapDrew]

Some relatives of mine (I love genetics) were in a "war" with a neighbor when one of them lit his shirt sleeve on fire with a bottle rocket.

Thats impossible! There's no way someone could light a whistling moon traveller and accidentally knock the bottle over while running away while it shoots across the front of a neighbor's sweatshirt lighting it on fire as he pulls it off and stomps it out! Oh wait...

The charge said INTO an Aircraft. She is great!!!!! hit a chopper with a bottle rocket what a shot!!

I'd like to see the hit. I can only imagine that the carnage is catastrophic!!! Twisted metal and burning bodies everywhere!
My buddies and I used to have fireworks wars when we were kids. bottle rockets, firecrackers, roman candles (those DO hurt a bit when you get hit in the chest wearing a t-shirt!). Wow just knowing we were waging full scale wars with missles is scary!

 

[velojym]

Also he must have been way below FAA regs for a bottle rocket to reach it.

JBTs aren't required to follow regs like us poor civvie pilots.

OOoooh, you guys are bringin' back memories...
We used short PVC 'launchers', roman candles, and of course the little strobes
in place of flash-bangs. Lots of small burns, ringing ears, and fortunately nobody put their eyes out. When we ran out of fireworks, it was back to BB guns.
Eddie Eagle woulda had our hides.

 

[Orthonym]

Oh, Limeyfellow, I resemble that...

but yer prolly right about most of my fellow doo-dah Floridians.

Do not people *UNDERSTAND* how hard it is to shoot at an aircraft from the ground, and hit it?

The United States Navy employed the smartest mathematicians and most brilliantly skilled engineers and machinists, back in the 30ies, to invent Radars, and very advanced almost perfect mechanical computers, with scientifically designed gun systems, to try to shoot down airplanes flying in a straight line, not dodging, at constant height. They mostly missed. Later, they went to proximity fuzes. That was somewhat better.

Jinking and dodging by the airplane will defeat these measures. Only very smart, latter-day homing missiles have a better than even chance of hitting a badly flown kite, let alone a helicopter!

Bottle Rockets? Pphhbbtt!

Dang, maybe I shoulda been more prudent when the local annoying copperflopper was beating around overhead and I flashed the strobe of my camera at it to get its attention for the middle finger I was raising!

 

[unspellable]

Bottle Rocket vs helicopter and other issues

There is a minimum flying altitude for aircraft over the city. One presumes the helicopter was above the minimum. The bottle rockets I have would never reach that minimum so whether or not they would rise through the down wash is moot.

As for the down wash itself, it's a WAY too common misperception that wings work on the Bernoulli principle, one even sees this error in high school text books. The Bernoulli principle has almost nothing to do with it, the idea that air flowing over the curved top of the wing prodouces a low pressure area has almost nothing to do with it. If that was the way wings worked there would be no ground effect, airplanes wouldn't be able to fly upside down, aireobatic planes wouldn't have symmetrical wings, helicopters would be able to hover in free air at high altitudes, and paper airplanes wouldn't be able to fly at all.

A wing prodouces lift by accelerating air in the opposite direction. Stand under a helicopter and you'll notice the downwash, or behind a propeller and you'll notice the back wash. You also have to account for a marine propeller operating in water, an incompressable fluid.

 

[72Rover]

Velojym wrote:

JBTs aren't required to follow regs like us poor civvie pilots.

OOoooh, you guys are bringin' back memories...
We used short PVC 'launchers', roman candles, and of course the little strobes
in place of flash-bangs. Lots of small burns, ringing ears, and fortunately nobody put their eyes out. When we ran out of fireworks, it was back to BB guns.
Eddie Eagle woulda had our hides.

Indeed. I'm surprised some of us made it out of childhood alive - or at least with most/all body parts still attached and functioning. We had roman candle duels, but - senesibly - used trash can lids for shields. When you had a gross of cherry bombs AND a slingshot, you had artillery. The ballistic coefficient of cherry bombs is vastly superior to that of M-80's....

 

[Brian Williams]

I had cobbled together a bottle rocket gun with a grip and a bic lighter attached so I could silde the rocket down the tube and the lighter lit it off thru a hole in the tube.

 

[unspellable]

altitude

I would think the police chopper would have the same flights regs as civy pilots. It's a basic safety thing. If the engine quits you want to be able to find a place to park it. This happened a while back in our fair burg. Police chopper engine quit. There were a few trees and utility lines to complicate the landing. Took our pilot several months to recuperate.

Gary Powers, of U2 spy plane fame, was killed flying a TV chopper. Ran out of fuel and made for a park playground, stretched the glide to miss some kids and stalled. You are not supposed to run out of fuel. The best of gliders in the chopper world make only mediocre gliders in the fixed wing world.

 

[DRZinn]

Perforate the cap.

 

[MLB]

There is a minimum flying altitude for aircraft over the city. One presumes the helicopter was above the minimum. The bottle rockets I have would never reach that minimum so whether or not they would rise through the down wash is moot.

As for the down wash itself, it's a WAY too common misperception that wings work on the Bernoulli principle, one even sees this error in high school text books. The Bernoulli principle has almost nothing to do with it, the idea that air flowing over the curved top of the wing prodouces a low pressure area has almost nothing to do with it. If that was the way wings worked there would be no ground effect, airplanes wouldn't be able to fly upside down, aireobatic planes wouldn't have symmetrical wings, helicopters would be able to hover in free air at high altitudes, and paper airplanes wouldn't be able to fly at all.

A wing prodouces lift by accelerating air in the opposite direction. Stand under a helicopter and you'll notice the downwash, or behind a propeller and you'll notice the back wash. You also have to account for a marine propeller operating in water, an incompressable fluid.
__________________
unspellable

Oh Bother! (as a favorite character bemoans.) Now I have to go look this stuff up. I would have sworn that wings, if not helicopter blades, work by creating a low pressure area above the wing creating lift.

Your examples of paper airplanes and incompressible fluids are tough to reconcile with this. I don't see how paper airplanes accelerate air either though...

 

[unspellable]

wings

Beware while looking it up. You will find many apperently "authoritive" references that spout the old Bernoulli canard. There are a number of sites on the web that explain the way wings really work though.

As for the paper airplane, or any other wing for that matter, it's angle of attack. Assume the paper airplane is flying at a constant altitude. The front edge of the wing will be higher than the rear edge so the wing is inclined and deflects air downward. Same applies to the symetrical airfoil on some areobatic planes. If you look at a table top electric fan, most have curved sheet metal or plastic blades that are not thicker in the center like most airfoils, but do have visible pitch. So a little observation makes it fairly obvious how the fan is pushing air.

We have a photo around here somewhere of a business jet flying over the upper surface of a cloud so that you can clearly see the downwash from the wings as it disturbs the upper surface of the cloud.

BTW: I had an uncle who was flying a 1949 Funk when the control tower launched an airliner too close behind him. It passed over him and the downwash put him into the deck. Totaled the Funk and nearly totaled my uncle.

 

[MLB]

Would you say that this would also apply to the sail on a boat?

 

[unspellable]

sails

Yes, a sail is (in most cases) nothing more than a wing stood on end. The exception is when the wind is behind the vessel when the sail is then being used as a simple drag device like a simple parachute rather than as an airfoil. It's less efficient this way, that's why a sailing vessel is faster with the wind across the beam. Also explains why a sailing vessel can sail close to the wind and by tacking progress up wind.

You will note that in some very modern concept designs the sail actually has a rigid thick section like an airfoil and actually looks almost like an airplane wing stood on end. The rub here is, if asymmetrical for best efficiency, it then becomes right or left handed, i.e. it works much better for wind coming from one side of the vessel than the other. Making a rigid thick section wing with a reversible configuration gets to be a much more complicated trick.

The idea is that such sails could be used on cargo ships to drastically cut fuel consumption. Modern power controls would eliminate the need for large crews to handle the sails. That's what killed off the sailing vessel when steam came along, not that steam was any faster. Some of the old clipper ship speed records still stand today.

This is sort of wnadering away from the original topic though.

 

[unspellable]

Closer to topic

Did anyone hear about the guy who flew his model airplane through the side of the Goodyear blimp a few years back? The blimp visited here and I went out to see it. Two weeks later in California this guy flew his model (good sized one) through the side of the same blimp. Made a six foot hole followed by an emergency landing in a vacant lot. They had to come in and truck the blimp out.

The authorities started with six or eight counts of assualt with a weapon, one for each person on the blimp, as a local state level charge, followed by federal charges involving aircraft regulations, plus what ever else they could think of. I imagine the guy is still in a lock up somehwere.

 

[velojym]

Ah, the old lift debate.
It's actually both. I learned this the 'hard' way in a flight physics class.
A flat plane will deflect air downward, depending on its angle of attack, but
can only do so much without the topside air breaking loose (a stall).
The airfoil shape better directs the air over the cambered wing and allows a higher aOa without stalling.
The Bournoulli effect is noticeable, and there is lift caused by the pressure differential between the upper and lower surfaces, though neither theory will keep your aircraft from droppin.
We have a model plane at the aerospace museum here, yet another flat-winged invention that never got out of ground effect. Airfoils wouldn't have done the inventor much good in this case, due to an underpowered engine and way too much weight.
We ran some classroom experiments with either theory, and various combinations of both. The best result came from pretty much what we see flying around now.
I guess we're getting kinda off topic now, eh?

 

[50 Freak]

Does this now mean that every year on the Fourth of July, tens of millions of American kids are now felons????

 

[DoubleTapDrew]

At the waterfront park fireworks display on the 4th of July people pay a lot of money to ride in a helicopter that will take them close to the action, and those are the huge electonically fired mortar shells.

 

[308win]

The Bushies are chalking this up as another terrorist plot interdiction as we speak.

 

[Taurus 66]

All the bottle rockets I ever fired off went skyward right around 100 feet at best, and I've tried many different kinds. The mortar rounds would be able to climb higher, but the news story stated it was bottle rockets. Are the cops flying low enough to be within bottle rocket range? If this is true, fireworks are one day going to be the least of their worries. Darwin will catch them sleeping at the controls.

 

[MLB]

Thanks

Velogym & Unspellable, thanks for the airfoil comments. I'm going to drop it in this thread before it gets too far off topic though.

Take Care,
MLB

 

[gezzer]

I have heard the only reason helocopters can fly is that they are so ugly the Earth repels them

 

[winchester62]

Unspellable,
You are kidding I hope. Is the world flat too? Where, praytell did you get your aero engineering degree?

 

[Orthonym]

Gee, This Thread Is Getting as Silly,

...as the notion that a rational helicopter pilot would feel the least little bit threatened by seeing someone launch a bottle rocket in his general direction.

 

[Bluehawk]

I think the engineering aspects of flight is beyond the scope of this forum and most here but having been a licensed pilot since 1981 and licensed A&P (aircraft) mechanic since 1986 for a major airline I think I'm qualified to mention something which has not been stated here...thrust + lift overcomes drag + gravity and aircraft airfoils do work on the high pressure/low pressure (lower surface/upper surface) principle. (Look up the effects of wind tunnel experiments useing smoke at high angles of attacks and burbbleing from the CG to the trailing edges at stall.)
Many airfoils are different and are more efficient than others...flat bottomed..semi-symmetrical...fully semmetrical...all for different purposes.
From there you get into dihedral...percentage of chord...wingtip washout...etc.
I can say from experience having flown rotorwing aircraft from the beginning that at full throttle with full down collective...zero collective/flat pitch.. on the ground...that you will never get a bottle rocket through the blades...you cant get a broom through them!!!! (we use brooms to lift the blades in windy conditions or to help track the blades) In flight with pitched blades I doubt sincerely you will ever get something like a bottle rocket anywhere near the blades.We all should know by now that the common bottle rocket doesn't fly more than 30-40 feet into the air...it's a rare one that goes much higher!
FAA Regulations concerning altitude is 1,000 feet AGL (above ground level or above the tallest structure) for densely populated areas, 500 feet AGL for sparsely populated BUT in the case of law enforcment it will depend on local ordinances and ultimately is up to the discretion of the controlling FAA authority in that area (nearest control tower/radar facility)
Homeowners Note: You may or may not own the airspace above your home...check your mortgage/deed paperwork...some show that you have signed it away others have not...if you haven't signed it away then you have the right to ask the FAA to route aircraft around your residence to keep the noise factor down. At the very least you can keep the police aircraft from flying over your home at 3 in the morning and being a nuisance!!!!!

 

[velojym]

Ah, but we can't keep our "betters" from doing what they durned well please.
I used to service the State Police helicopters as well as some other state & fed planes, including that big blue and white one that gets so much attention
The pilots have differing attitudes just like anyone else, but the general consensus with them is that they don't have to worry nearly so much as a run-o-the mill pilot about breaking rules.
Heck, I've seen the FAA guys do crap they'd have your ticket for.