Low-flying helicopters. Black and unmarked

a reply to: Zaphod58

It's the Doppler Effect. Once they get in an area where the rotors are pointing away from you somewhat, and there are buildings and trees around, the sound tends to get blocked, and distorted. I see that a lot with planes going overhead too. The plane will be a few miles ahead of where I'm hearing the sound, so I'm looking one way and it's already past where I'm looking.

The Doppler effect is strictly a frequency shift.

When you view aircraft, the sighting is at the speed of light, while the sound is at the speed of sound. Hence the sound you hear is delayed. ;-)

I've watched live bombing from a safe distance, and the speed of sound is way slower than people think. Bombing in real life doesn't look like bombing in the movies.

To understand markings on aircraft, you need to understand the modulation transfer function.
MTF
I have photographed choppers with light grey markings over dark grey paint. Many cameras will lose the marking if the sky is bright. Your eye, which also has MTF issues, tends to scan the scene, and it looks for contrast. The contrast is at the edge of the aircraft with the sky, so you tend to miss the markings.

Ghost Squadron at Basecamp　Ｎｅｖａｄａ

a reply to: Zaphod58

The military while stateside observes FAA rules except when doing tactical training but there's areas designated for that. Most of the comments that I've read here sounds like normal training to me. Back in the day, I went to summer training with several other aircraft flying in a trail formation across Ohio and Kentucky to either Ft Knox or Ft Campbell. We would stop to refuel periodically at small airports for no other reason than not to screw-up commercial operations at larger airports. The operators of the small airports loved to see us coming because of the fuel we bought would equal several months of fuel sales to civilians.

The "black" color on army helicopters is actually dark green and it's black appearance come additives to the paint that, in theory, reduces the ability of ground to air (manpads) missiles to lock-on to the helicopter. There's also other equipment onboard to aid this ability as well.

I also read about long pipes coming out of the front of the helicopter. These are refueling probes but are only found on army special operation, air force rescue and marine aircraft. Civilian helicopters are not permitted to use this equipment due to the training and risk involved.

I really don't think there's much to worry about seeing low flying "black' helicopters...they're probably just training. Back during the 1978 blizzard here those "black" helicopters dropped several tons of hay to stranded cattle while flying low.

a reply to: buddah6

That's exactly what I keep saying but black helicopters are sexier than green.

a reply to: gariac
I think the gray aircraft that you're seeing are navy or marine...I believe they still use this color due their operation at sea where most everything is gray. The army tried this color on it's airplanes in the 1990's but I'm not sure it was continued after I retired. I'm aware that the army painted some airplanes and helicopter sand (loam) color during operations in Iraq. My planes ( OV-1D) were gray with dark gray and black markings during that time.

I didn't see your pictures of the USAF HH-60's so I humbly stand corrected.

a reply to: Zaphod58

You are so right! But after doing it for 24 years it was good to go to work for a company that flew bright colors and good looking flight attendants rather than a hairy ill-tempered crew chief...LOL.

a reply to: buddah6

We had VIP C-135s at Hickam. No hairy crew chiefs or stewards for CINCPACAF or CINCPACFLT.

a reply to: Zaphod58
You gotta remember that I was in the army. My general only had a C12 to ride around in and it wasn't set up for VIP travel. Your Hickam assignment must have been cool! I guess that Ft Huachuca, Arizona in August doesn't give the same dark tan...lol.

There was a KC135 unit colocated on the same field as mine and they could take family members along flights which I had always envied. No one wanted to ride in our Mohawks even the crews. Only newbies were excited over flying them but after a couple 4 hour hops sitting on those hard-ass seats all the excitement went away.

There were a couple of USAFR C9 drivers that flew with me at my civilian job and they took great pleasure in rubbing in how cushy their assignments were. It was good fun!

a reply to: buddah6

If I can get them to upload I have the perfect pics for this thread. Sitting in a truck stop and there was a drop deck trailer with a Blackhawk sitting on it.

Yeah I miss Hickam. Used to love watching people come through and fry, walking back out to their birds redder than choked lobster, knowing that -30 temps waited for them.

For some reason it rotated the pics when it uploaded them, but here's a great example of what I've been saying.

This was taken from about 30-40 feet away, of a disassembled Blackhawk being transported by truck. It's sitting still, and I zoomed in. These are the markings on the tail boom of the helicopter. If they're that hard to read, while being that close, and it's sitting still, what makes you think you're going to see them when they go flashing by at altitude?



This is it sitting on the trailer. It gives you an idea of how the color can appear different even at close range, sitting still.

a reply to: Zaphod58
I think this paint scheme came about in the mid 1980's and that's when the army started painting some of our planes gray. I can only speculate why the markings became subdued. The insignia on our uniforms when dark as well. I had thought the move was due to the emphasis on the use of the night fighting doctrine and night vision goggles.

My pet theory is the military is using mimicry in that many of our aircraft look so much like Russian and Chinese warbirds. I've read a study published from the Nadic Labs many years ago where this may be used to protect future aircraft, I can see this happening for example with the AH 64 and the Mi 28. If the national markings were subdued it would be difficult to discern whose aircraft is being shot at after dark since both helicopters look similar. Another cool story is how the stealth fighter was painted black. The Nadic Labs found the best color for it was a pastel blue/gray for night ops. The commanding general insisted that the USAF didn't fly pastel airplanes and they were painted black.

a reply to: buddah6

Yeah, black sucks for night flying. But the Generals have to have their way, even if it's something incredibly stupid. They were actually testing the F-117 with a grey paintjob so they could fly it during the day when it was retired. The B-2 has gone to a dark grey color with the latest skin.

a reply to: Zaphod58
I made another mistake in my last post as to the time frame of the paint job of the H60 in your pictures. I was thinking of when the H60 came into the inventory but I missed the paint question. Let me try again. The Blackhawk is in the standard army paint scheme of the time (early 1960's). It is painted in standard army aviation green and not the IR suppressing paint (black appearing). I don't know when the IR paint was introduced but the first time that IR missiles (SA7s) were use against my unit was at An Loc Vietnam around May 1972. We received exhaust kits in short order to blow the engine exhaust up into the rotors for cooling.

I think where my memory failed was when I attended flight school the UH1B's we trained in were still in bright paint but they were built around 1960 and the other helicopters were bright orange. Bright paint was full color national insignia and yellow US ARMY and bureau # over olive drab.

On further reflection, the gray paint of the mid 80's was possibly for aircraft that operated mostly during the day. It is difficult to see with the naked eye and doesn't absorb the sun's heat so it's more difficult for IR missiles to acquire as a dark color would. This brings me back to the idea of the dark color aircraft are for the army's night fighting doctrine. If the paint is dark so it is visually difficult to see at night and the paint suppresses the IR controlled weapons this only leaves the mark one eyeball to shoot at the helicopters. This can be addressed by flying low as not give the bad guys only a few seconds to shoot at us.

How would our antagonists counter our night warfighting doctrine? They would build aircraft that looks very similar to ours to confuse the warspace. They know the average person can't identify most aircraft. This is known as the "Piper Cub" effect. The average guy that sees a small single engine airplane refers to it as a Piper Cub whether it is or not. It's like this thread where all low flying aircraft is up to no good. Black helicopters are the favorite complaint...the medical flight helicopter here happens to be black with red markings and 50 miles up the road their medflight helo is dark blue with white markings. Our sheriff's helo is black with gold markings as are most civilian government aircraft. The boarder patrol's helos are dark green with white markings. Military helos are different low-vis colors but one thing all of these helos have in common is they all need to train for their mission. This training can not all be done in military operating areas (MOA) so the "Piper Cub" crowd will see "black helicopters" from time to time.

For those who see and hear "black helicopters" rest assured that they are not after you! If you are the target, you will only hear the helo about 20 seconds before the spec-ops guys will have you! That's what they train for and they are dedicated to keeping you SAFE by doing it.

a reply to: buddah6

I was watching Tour of Duty the other day (love that show), and I noticed what looked like an exhaust blower on the engine of the helicopters they were using, but couldn't remember when they started doing that. I'm a stickler for technical details, so that's been bugging me. But I guess that answers that question, and makes it technically accurate (I love when shows get the little details right).

The funniest thing I heard, and didn't believe at first, was that when fighting at night, the best thing you can do to make a plane invisible is light the sucker up. If you put the lights at a certain distance, and they're a certain color, the brain will dismiss the aircraft as being a star/planet and it tends to be ignored.

a reply to: Zaphod58

If the aircraft is at altitude and fairly quite, I can vouch for that.
As an amateur astronomer I've spent a fair amount of time under the stars on clear moonless nights. It is easier to spot the stars being occulted as opposed to points of light moving slowly across the sky. In modern times they are ignored and misinterpreted as common satellites.

a reply to: Sammamishman

I watched blacked out helicopters flying over the NTTR twice through night vision. I have Soviet era gen 2 gear. You can see the blacked out shape against the night sky. That is why I agree with Zaphod58 that black is the wrong color for night time stealth, though I don't really know what would be appropriate.

Regarding shining a light on an object to make it disappear, the idea is to match the background illumination. This is hard to do because your light source will always appear as a point source, while the background illumination comes from a planar source. These sources will have fall off using different equations (inverse cube versus inverse square I think), so you could only do the illumination trick if you knew the distance to the observer.

I knew of occultation as a noun, but not the verb form. Sounds like Satan worship to me, er not that there is anything wrong with that.

a reply to: gariac

oc·cult

/əˈkəlt/

verb

past tense: occulted; past participle: occulted

cut off from view by interposing something.
"a wooden screen designed to occult the competitors"

•Astronomy
(of a celestial body) conceal (an apparently smaller body) from view by passing or being in front of it.

a reply to: Zaphod58

The exhaust kits that I referred to was just a tube bent 90 degrees that attached to the engine exhaust pipe and it wasn't a blower. This did two things, first redirected hot engine gas up into the rotor wash which cooled it to a point where an IR missile had difficulty locking on to the helicopter. Second, the shape of this tube blocked direct viewing by an IR source below and behind the helicopter from the ground perspective. This was use on the Huey and Cobra helicopters. This concept was designed into the modern helos...Blackhawks and Apaches.

gariac, Helicopters flying blacked out doesn't mean you can't see them with NVG. It just means you see them for a shorter period of time. The helicopter crew can change the time you see and hear them by adjusting their altitude and flying "Nape of the Earth" which is 5 to 50 feet height. One other thing that you need to consider is the vast majority of modern armies still don't have NVG let lone NVG for every soldier like the US.

The Nadic Labratories has new technologies that makes aircraft 95% invisible by photographically imaging the sky above the aircraft and displaying it on the bottom. Unfortunately, this technology is too heavy for use on helicopters. This is why you see helicopters like the one that crashed on the Bin Laden raid.

a reply to: buddah6

I don't know if this is an actual blower, but it looks like one. I dealt with fixed wing, the only helos around were the Test Group aircraft, and once they left we didn't have any helos on base.

It's close to this, just above the door, behind the rotor mast.

a reply to: Zaphod58

Looks like maybe intake/cooling louvers for the turbine?

www.aircav.com...

www.scale-rotors.com...

a reply to: Sammamishman

Yeah that could be it.