The AH-64 Apache Thread

[rcjonessnp175]

Well blue on blue is another unfortunate reality that happens in combat. Despite all the technology and training it still happens. It's simply another price that is paid for our freedoms, and trust me aars are very thorough after any loss of life in order to prevent future loss of life.

Myself well not getting to personal lol yes I started out infantry in the Ranger regiment, now I am a green beret, who is actually looking to put a flight packet in. My experience is all ground stuff ya I jump out of airplanes and fast rope out of hellis that's about it as far as air.

Job sucks at times when bad things like you mentioned happens. Best thing you can do is honor those who have fallen and continue the fight so their deaths where not in vain.

Back to Apache stuff looks like my fiances cousin who is a crew chief will give a good hands on tour of the new birds, look forward to it. Like always I myself and my brothers have the utmost respect for our brothers and sisters flying over head.

[wellen1981]

Well blue on blue is another unfortunate reality that happens in combat. Despite all the technology and training it still happens. It's simply another price that is paid for our freedoms, and trust me aars are very thorough after any loss of life in order to prevent future loss of life.

Myself well not getting to personal lol yes I started out infantry in the Ranger regiment, now I am a green beret, who is actually looking to put a flight packet in. My experience is all ground stuff ya I jump out of airplanes and fast rope out of hellis that's about it as far as air.

Job sucks at times when bad things like you mentioned happens. Best thing you can do is honor those who have fallen and continue the fight so their deaths where not in vain.

Back to Apache stuff looks like my fiances cousin who is a crew chief will give a good hands on tour of the new birds, look forward to it. Like always I myself and my brothers have the utmost respect for our brothers and sisters flying over head.

 

Yeah, being a spectator to all the things you all go through you could be forgiven for thinking I would be careful and diplomatic about my views on it but I honestly have to say I genuinely feel bad for all involved in those incidents - wiki has 8min cockpit video of another incident going wrong and although the outcome was strained for US-UK relations I have to say that while I am saddened that lives were lost in error, the pilots real-time genuine words were said to offer no thought for the lives he had taken. To my ears I just heard human shock at what he had done.

It is too easy for civilians to judge from the comfort of chairs but only you all watching out for each other and yourselves truly know what you are up against.

 

Thanks for the reply.

 

And your service.

 

Also, the media which folks at home get fed has a very deliberate angle when it comes to covering conflict and it never truly captures the full story of war.

As those that actually serve, how would you all feel about the general public actually having an accurate handle on the things that happen during conflicts eg the successes AND the failures - would you prefer civilians to have accurate coverage of what you all go through or do you actually prefer that they don't know the half of it?

 

My phrasing at the end there is lacking and could be read badly but I just mean would you all feel better if civilians knew more about what you go through or do you prefer the public are not given the very bad stuff - eg kinda shielded from the very bad details?

 

Anyone could argue that it is all online (eg on wiki) to find and read but the average person would never go out of their way to find out about such subject matter and the only way the average person learns of such things is through mainstream media eg tv shows, films, video games.

 

Back to ah64s.. you think it will be the 64-d or the 64e?

Edited December 13, 2014 by wellen1981

[rcjonessnp175]

They have the beautiful Echoes here. Everytime I drive to the sniper range I drool over those puppies. Beautiful birds.

 

 

Me personally I think the public knows to much as is. Hence why we get ridiculous Roe thrown down our throats that prevent us from winning the war. It's all politics and would only get worse if everybody knew exactly what goes on down range. Politics anger me so that's all I'll say.

Edited December 13, 2014 by rcjonessnp175

[wellen1981]

They have the beautiful Echoes here. Everytime I drive to the sniper range I drool over those puppies. Beautiful birds.

 

 

Me personally I think the public knows to much as is. Hence why we get ridiculous Roe thrown down our throats that prevent us from winning the war. It's all politics and would only get worse if everybody knew exactly what goes on down range. Politics anger me so that's all I'll say.

 

Every time I go to post I read the warning at the top regarding politics.

 

War is ugly business and in the moment of survival civilians (most of them anyway) don't even factor in that for those that serve, it is about survival on an individual, per-person level at that precise moment - then in the following moments about making sure those around you survive.

 

You comment on ROE is something I have been looking into a lot recently (given my recent knowledge of what was done to a captured female pilot out in Iraq and also what was done to Iraqi enemy forces in trenches using earth-moving vehicles) and from what I can tell, it only serves to protect you all - from the backlash you would each face personally when getting back on homesoil for your actions out there. Completing objectives is one thing, but being hated by those you fight for is too big a price to pay for each and every one of you, regardless if it would get the job done easier and quicker/safer. I for one am glad they don't let you all loosen the rules of engagement but I completely understand that you and I might not agree when for you that could mean a child outside a base informing the enemy of your activities through phone or radio. I really don't think any of you guys on the ground want to be the one who takes that childs life and then have the media (and then the public) find out.

 

While I would be the last person to want secrets kept from the public regarding what goes on, even I find it difficult to argue that the public knowing more would maintain freedom (which can only be kept through military existence) going forward.

 

Everything comes at a price, some people enjoy the freedom without realising where it comes from and who gave their lives to buy it.

I hope from the posts I have made in here it shows that while I very much dislike war, (having spent a lot of time researching what specifically happened in both Iraq and Afghanistan) even I realise war at times is a necessary evil and politics and the realities of war are two totally different things.

 

Thanks for the short reply, I appreciate the honesty.

 

On topic and to all... (not sure if this will be classified but I can always ask I guess (I hope?)

 

Radar in military use, in for example the F-15 and F-16, is it true that before launching a missile the pilot does something in relation to the radar or jamming systems that could cause lights to flicker below on the ground eg in buildings etc?

 

The on-topic bit (and possibly classified again), do these systems in planes also make it into the likes of the Apache eg the featuresets. Or, as they are made by totally different airframe manufacturers is the tech in certain airframes only included in other airframes by the same manufacturer or do the military (through the undertaking of the contract) get to utilise tech from an airframe in future airframes made by different companies - so in a very unclear way I guess the last bit I'm asking is, does the military own total rights to the tech to use in future products regardless of which company wins the contract to manufacture future airframes.

 

:huh:

Edited December 21, 2014 by wellen1981

[Milliontrax]

Sorry to bump this thread but I've been reading all of nightmare's posts with intrigue. Had a few questions of my own I didnt see answered. Also I got attacked on a different forum asking questions about F-16's once so I understand if any of this information is classified or whatever. I dont work for NK, the taliban, russia, etc. Just someone who fantasizes about flying for the military imagining what my routine would be like.

 

Could you describe the startup sequence for the engines in the apache? At what point do the engines begin delivering power to the rotors during startup? It seems like it would take an incredibly strong electric starter to begin spinning one of the turbines and the main rotor all together at the same time. Does the first engine spin up, ignite, and then engage the rotors via some sort of clutch? Or do the rotors begin spinning the second the engine starts trying to spool up? Every startup video I have seen seems to suggest the latter, whereby the rotors slowly start spinning immediately and you can hear the turbine spooling up before it ignites. But then again I saw one apache startup video where it appeared both engines must have been at idle or something because suddenly the rotors just instantly jerked into near full RPM, almost to the point where you would think they were damaged in doing so. Maybe both options are available and the engines can fully disengage at will?

 

What does the 2nd engine do before ignition while the first engine has the entire aicraft powered up? Does it just sit there spinning?

 

What is this thing?

 

The gunner users the larger optical array located at the front of the helo right? And the pilot has a smaller rotating unit that sits above. Do both possess the same range/capabilities? Or can the gunner see much further from what appears to be a much larger lens?

 

How fast can you become airborne when called to duty? I know for instance in the air force and navy they have some kind of "quick reaction" line whereby a few aircraft are already fully pre-flight and basically ready to just start the engines and take-off at a moments notice, thus giving them mere minutes to become airborne if called in for some kind of emergency. Do apache pilots operate with a similar system?

 

When you arent on some kind of quick reaction line (if it exists), how long does it take on average to actually become airborne from the moment you step inside the cockpit? How long is your internal preflight regimen before you lift off?

 

Do apache pilots ever have missions that consist of just loitering about the area so they can respond to emergencies? Or is every flight a preplanned attack on a specific target?

 

When ground troops call in support for apache's how long do they usually expect to wait? Like if there is an emergency and they are under fire do they sit back for a solid 30 minutes or something? It seems like unless there were 1000 apache's flying all over iraq every day it could take quite awhile to reach assistance on occasion.

 

What do you do when you're not flying? Like if you only go up 2x per week, what is the rest of the time spent doing? Planning the next mission? Flying the simulator? Doing completely unrelated tasks like paperwork? Just sitting around bored off your ass watching TV?

 

You mentioned blackhawk pilots get more airtime than apache pilots simply because there's more for them to do. How much more time are we talking here? Do they get to fly damn near every day? Would you even necessarily want to fly more than you do right now? Or is twice per week enough to satisfy you and you could actually use the down time?

 

How many apache pilots do you know of that have nothing more than high school degrees? I know to become one that is all that is required, but I'd figure everyone would be applying for flying jobs if it were that easy. Do you find that most army helo pilots possess additional education beyond just a HS degree? Like an associates degree most likely? Or is there a realistic chance that most people really could just walk into a recruiters office, request to become a pilot, and assuming they are pretty intelligent and do well on all of the tests actually land a slot?

 

 

Thanks for whatever questions you are willing to answer :)

Edited February 7, 2015 by Milliontrax

[Yurgon]

Had a few questions of my own I didnt see answered. [...]

 

I could guess or deduct some of the answer from my DCS experience with choppers, but everybody's time will be better spent when someone who actually knows this stuff answers. :)

 

However, I would highly recommend you read "Apache" by Ed Macy. It does answer quite a few of the questions. Just be aware that he flew Apaches for the Brits; the US or other forces may have different procedures (also, the AH Mk1 is based on the AH-64D AFAIK; newer AH-64Es may have different specs and/or use different procedures).

 

On top of that, it's a very well written book, I can't recommend it enough. If you have a few bucks to spare, get "Hellfire" along with it, also by Ed Macy.

[Raptor9]

[snip]

 

Milliontrax, while I can understand your fascination with a lot of these things, some of your questions are a slippery slope. While the answers to these questions aren't in themselves classified, they are sensitive in nature. Knowing reaction times of crews, equipment, ranges/capabilities of sensors, etc. can all be consolidated and used to develop counter-tactics against ground forces or aircrews themselves.

 

I'm not attacking you in any way, I'm just explaining how some minute details that may seem innocent on the surface can be detrimental to real people out there. These forums are open to be read by the international community.

Edited February 7, 2015 by Raptor9

[Milliontrax]

Thanks guys I totally understand not being able to discuss certain details, I'll take what I can get since everything fascinates me so much.

 

Other question - do the crew fly around with the monocle HUD thing in front of their right eye at all phases during flight? Or do you only adorn that during combat?

 

On the D model apache's the gunner has some kind of mounted googles in the center stack he can plant his face into (replaced with a 3rd screen on the new E models it seems). I thought the monocle eyepiece handled all targeting and firing operations (including flight instrumentation). What is the relation between these 2 devices and how are each effectively used?

 

The new E models appear to have vectored the exhaust from the engines straight up into the main rotor. I assume this improves heat dispersion to avoid tracking (and maybe adds some de-ice to the main rotor?)

Edited February 7, 2015 by Milliontrax

[AlphaOneSix]

The monocle HUD, it's called the IHADDS...well that's what the who system is called, the display on the helmet is called the HDU (Helmet Display Unit).

 

The gunner's thing you're talking about was the interface for the HDD (Heads Down Display) and the ORT (Optical Relay Tube). It allowed you to see the display from the selected sight as well as some additional information on what was called a HAD (High Action Display) below the sight picture. It also allowed use of the DVO (Direct View Optics) which allowed a magnified view through the day sight that was purely optical with no electronics in the way (all mirrors/lenses). The DVO and ORT were removed on the Block III AH-64D, which became the E-model, and was replaced with another display.

 

The upturned exhaust is just to improve passive IR protection, I don't think it would help much (if at all) with icing, and it is certainly not designed with that in mind.

[AlphaOneSix]

Sorry to bump this thread but I've been reading all of nightmare's posts with intrigue. Had a few Could you describe the startup sequence for the engines in the apache? At what point do the engines begin delivering power to the rotors during startup? It seems like it would take an incredibly strong electric starter to begin spinning one of the turbines and the main rotor all together at the same time. Does the first engine spin up, ignite, and then engage the rotors via some sort of clutch? Or do the rotors begin spinning the second the engine starts trying to spool up? Every startup video I have seen seems to suggest the latter, whereby the rotors slowly start spinning immediately and you can hear the turbine spooling up before it ignites. But then again I saw one apache startup video where it appeared both engines must have been at idle or something because suddenly the rotors just instantly jerked into near full RPM, almost to the point where you would think they were damaged in doing so. Maybe both options are available and the engines can fully disengage at will?

 

Start APU. (The APU provides pressurized air to the engine starters to start the engines). Move the start switch for one of the engines to START. The APU will deliver air to the air turbine starter on that engine which will cause the engine to start spinning. When the engine starts to spin, move the power lever for that engine from OFF to IDLE. The engine will automatically spin up to a certain RPM, fuel will start flowing into the engine, the igniter will light off the fuel, and shortly thereafter the starter will cut out and the engine will spool up to idle on its own. Assuming the rotor brake is off, as soon as exhaust gasses start flowing through the power turbine, the rotor will start turning. Note that there is no physical connection between the power turbine and the compressor (gas) turbine. The only thing turning the rotor blades is the force of the exhaust gasses flowing through the power turbine blades.

 

Anyway, you can then start the second engine just like the first. There is a freewheeling clutch that prevents the power turbine on the opposite engine from being turned by the main rotor. Both engines have this kind of clutch. In fact, all helicopters have a freewheeling clutch that allows the engines to drive the rotor, but the rotor cannot drive the engines (that would be bad).

 

Once both engines are started, the power levers are advanced from IDLE to FLY and and that's it.

 

The engines can be started with the rotor brake locked, in which case you can start the engines up to IDLE and the rotor will not turn. When the rotor brake is unlocked, you get that violent-looking jerk and fast spin up of the blades. This is done primarily to impress onlookers, but it has a secondary use during high wind operations to prevent the rotor blades from flexing up and down too much (and possibly striking the tail boom) during engine start when there is not much centrifugal force acting on them (or centripetal force, whatever, not an argument I want to have).

 

What does the 2nd engine do before ignition while the first engine has the entire aicraft powered up? Does it just sit there spinning?

 

If not obvious from above, the second engine just sits there doing nothing until it's started. It doesn't spin.

 

What is this thing?

 

It's an air data sensor for sensing the direction, velocity, and temperature of the outside air.

 

The gunner users the larger optical array located at the front of the helo right? And the pilot has a smaller rotating unit that sits above. Do both possess the same range/capabilities? Or can the gunner see much further from what appears to be a much larger lens?

 

Either pilot can use either sensor. Typically, the pilot uses the PNVS (the one on top) and the copilot uses the TADS (on the bottom). They have very different ranges and capabilities. The PNVS only has a FLIR sensor, but it's very good. The TADS has a FLIR (with more magnification capability than the PNVS, IIRC), and also houses the LRFD (Laser Rangefinder/Designator), and the DTV (Day TV) optics.

 

How fast can you become airborne when called to duty? I know for instance in the air force and navy they have some kind of "quick reaction" line whereby a few aircraft are already fully pre-flight and basically ready to just start the engines and take-off at a moments notice, thus giving them mere minutes to become airborne if called in for some kind of emergency. Do apache pilots operate with a similar system?

 

Nightmare will be able to answer this better than I can, but yes, if the aircraft and crew are standing by, they could probably get airborne within 5 minutes if absolutely necessary.

 

When you arent on some kind of quick reaction line (if it exists), how long does it take on average to actually become airborne from the moment you step inside the cockpit? How long is your internal preflight regimen before you lift off?

 

Another one for Nightmare, but when I was in it was about 15 minutes for all the preflight checks and whatnot.

 

Do apache pilots ever have missions that consist of just loitering about the area so they can respond to emergencies? Or is every flight a preplanned attack on a specific target?

 

It depends? But I would think this one is obvious, the vast majority of engagements are unplanned...at least the missines these days are. They occur during an escort or something where they act like scouts and just troll for bad guys.Of course there are also preplanned attacks, but not on a specific target, but more of a target area. In current conflicts, the bad guys simply do not make themselves available for preplanned attacks, generally.

 

When ground troops call in support for apache's how long do they usually expect to wait? Like if there is an emergency and they are under fire do they sit back for a solid 30 minutes or something? It seems like unless there were 1000 apache's flying all over iraq every day it could take quite awhile to reach assistance on occasion.

 

What do you do when you're not flying? Like if you only go up 2x per week, what is the rest of the time spent doing? Planning the next mission? Flying the simulator? Doing completely unrelated tasks like paperwork? Just sitting around bored off your ass watching TV?

 

Everyone needs time to catch up on Walking Dead and Game of Thrones!

 

Anyway, I left some stuff out that maybe Nightmare can answer better. I got out of the Army a long time ago and I was only really involved with the A-model, although I had had numerous opportunities to become rather well acquainted with the D-model, including the Block III (E-model now).

 

Disclaimer: I was not a pilot, but a mechanic on the AH-64A, which may or may not cause you to discount everything I just wrote, but that's up to you to decide.

[Milliontrax]

Thanks a lot alphaone, the questions about how the engines and drive systems work are actually the most fascinating for me anyway so that's what I was most hoping to learn about and you answered them perfectly. Could you explain what the following protrusion is and how it connects to the engines? I assume it's a drive shaft to the main rotor but find it odd that it could be placed in front of the engine if exhaust gasses are what drive the system. (Perhaps the shaft is connected to the rear of the turbine and runs straight through the compressor?)

 

 

 

I also have a question that has long plagued me regarding control inputs and blade pitch. So I understand the swash plate tilts putting pressure on a pitch rod that shifts the angle of each rotor blade. What I'm wondering is when the aircraft is moving in any direction other than straight up; it seems to me that the pitch of the blades on one side would have to be greater than on the other in order to generate unequal lift and tilt the helo over (for instance leaning to the left). If this is correct, does that mean the blades are oscillating rapidly up and down as they spin? It seems like this would make for a pretty bumpy ride.

 

Is the ADS (air data sensor) the only component for measuring altitude/airspeed? Does the apache lack a standard pitot tube and static air pressure monitor like an airplane would? And while you may not know this, are these kind of wobbling ADS's on every helicopter? I've seen it hanging off the front of the Cobra helo's, not sure I've seen it on Blackhawks and other's though. If not, why wouldnt they use this and what do they use instead?

 

Who is truly in command during flight? I've read that the pilot is usually the senior crew member in the apache and the gunners seat is where everyone starts. Yet I have seen several videos of cockpit footage where it appears the gunner is issuing commands to the pilot. Do they exchange command responsibility of the aircraft as needed? And I dont mean passing of the controls. For instance the gunner see's a target and thus tells the pilot where to fly to engage them. I feel I have also seen footage where it seems the pilot is telling the gunner what to shoot and for how long. How do the pilots work together? And do they ever fly alone or do you always fly with a wingman?

 

Speaking of passing the controls, cockpit pictures seem to depict the gunners seat as having smaller input devices to work with. They do not seem as large or robust as the pilots, most likely to make room for extra gunner equipment. Is this correct? While it is possible for the gunner to completely control the apache, is this only done for emergencies? I assume they do not regularly hand off controls to each other, nor would anyone want to fly from the gunners seat.

Edited February 8, 2015 by Milliontrax

[AlphaOneSix]

Could you explain what the following protrusion is and how it connects to the engines? I assume it's a drive shaft to the main rotor but find it odd that it could be placed in front of the engine if exhaust gasses are what drive the system. (Perhaps the shaft is connected to the rear of the turbine and runs straight through the compressor?)

 

It's the NGB (Nose Gear Box). You are correct, the power turbine drive shaft runs forward inside the compressor drive shaft, and into the NGB. The NGB just redirects that power 90 degrees into the main gearbox.

 

If this is correct, does that mean the blades are oscillating rapidly up and down as they spin?

 

Yes, the blades are constantly changing in pitch as they go around, but it's designed to do this, and the blades a "trimmed" and balanced so that the vibrations are typically not so bad.

 

Is the ADS (air data sensor) the only component for measuring altitude/airspeed?

 

Nope, there are "normal" pitot tubes on the front outer ends of the wings.

 

Who is truly in command during flight?

 

The PIC (Pilot in Command) is in charge. In most cases, that's the higher ranking/most senior pilot in the aircraft. Also, it's usually the guy in the back seat. As you mention, however, it's a team effort, so even if the pilot in the back is the boss, if the gunner needs the aircraft to move a certain way, he'll just tell the pilot what to do.

 

Speaking of passing the controls, cockpit pictures seem to depict the gunners seat as having smaller input devices to work with. They do not seem as large or robust as the pilots, most likely to make room for extra gunner equipment. Is this correct? While it is possible for the gunner to completely control the apache, is this only done for emergencies? I assume they do not regularly hand off controls to each other, nor would anyone want to fly from the gunners seat.

 

The controls are cyclic and collective controls are identical in the front and back seats. Typically, the guy in the back flies, but it is routine for the guy in front to fly. Nothing wrong with flying from the front seat, and I'm sure when the guy in back wants a break, the guy in front is more than happy to fly for a while.

[Reagan505]

Hello,

 

First off, I just want to let everybody know that I'm not trying to be an A-Hole.. I love DCS, aviation, (Especially Russian aircraft) and realize most of the stuff in the forums is harmless curiosity - Been there. A lot of countries, (Our allies) fly the 64 and are currently using them in active combat operations.

 

Hey American pilots and crew-chiefs.....Don't forget this is an international forum, hosted by the RUSSIANS! Not saying we need to worry about the Russians, (Because they're our friend's and already know all of this stuff) but Jihadis can, and do hop on this forum also.

 

Questions about aircrew tactics, spool-up time, (How long from cold start til on station) QRF, etc, based questions shouldn't be shared on an INTERNATIONAL PUBLIC FORUM. It generally doesn't take long to start a helicopter, unless it's Russian ;)

 

The AH-64D's and E's still have a lot of sensitive info, which isn't exactly a secret, but an adversary who has intricate knowledge of an enemy weapon system can develop tactics to bring that weapon system down. If MANPADS aren't available, but small arms / crew served weapons are, these guys could develop tactics to successfully employ these smaller / bigger caliber weapon systems and will have specific areas of the aircraft to shoot at. I know that sounds overkill, it's just an example of why some info shouldn't be shared openly on an international public forum. Let these people do their own homework in regards to their specific questions pertaining to the AH-64.

 

Like I said, the Russians already know most of the important stuff about the 64, but stop volunteering avionics, targeting info, tactics, etc.. All you 64 drivers and crew-chiefs posting info, F'ing know better!

 

That is all.... Not trying to be a dick... Start-up procures isn't anything special... Just be mindful of what kind of UNCLASSIFIED information you are posting on this international forum, along with aircrew operations.

 

Thanks for your time and DCS rocks!

Edited February 9, 2015 by Reagan505

[AlphaOneSix]

Everything I post is either from a military publication that is approved for public release without restriction, or is available in the manufacturer's brochures. I would hope that anyone hoping to gain information would be smart enough to get it from those publicly available sources rather than trust me, I could be lying to you.

 

I know the old argument "it may be publicly available, but you don't need to be one more source" argument, and I find it to be invalid. Mostly because the actual, authoritative sources are readily available and guaranteed to be correct, while my information is subject to my recollection and is inherently less reliable.

 

I could refute your points individually if you'd like, but unless you ask me to, I won't.

[Reagan505]

Do what you need to do Alpha-One-Six. I don't really care either way, already said what I wanted to say. Are you affiliated with 2-101? Crew-chief or Pilot? You obviously missed the point I was trying to make. I see you have the title of being a video-game tester for ED.... So I would imagine you have all the time in the world to refute the content of my post listed above. Go ahead if you want to, but honestly, it would be a waste of time.

Edited February 9, 2015 by Reagan505

[AlphaOneSix]

Do what you need to do Alpha-One-Six. I don't really care either way, already said what I wanted to say. Are you affiliated with 2-101? Crew-chief or Pilot? You obviously missed the point I was trying to make. I see you have the title of being a video-game tester for ED.... So I would imagine you have all the time in the world to refute the content of my post listed above. Go ahead if you want to, but honestly, it would be a waste of time.

 

I actually have very little time, and I agree that arguing would be a waste of time. We each have our own opinions and witty banter on this forum is unlikely to convince either of us that the other's opinion is more correct. I may or may not have been or am currently affiliated with the 2-101st. I see your point perfectly, I just don't necessarily agree with it.

[Reagan505]

Fair enough Alpha.... I answered my own question earlier btw... You're a Crew-Dawg.. Safe travels com-padre

[Milliontrax]

Yeah I dont want this thread to turn into a pissing contest. Last time I asked similar questions about an F-16 and someone accused me of trying to learn startup procedures so I could steal one! I think we all get where my curiosity is coming from. Every hollywood movie makes sure to glorify cockpit procedures of aircraft, but they often leave things unanswered for us detail oriented sticklers. I just try to walk the fine line in between. I wont waste my time asking what kind of resolution the longbow radar can read targets at or how the hellfire missile sees a laser designator. Answer whatever questions you are comfortable with, and a major thanks to alphaone for satiating my appetite for knowledge, all of which I think is well within the grounds of harmlessness. Watching Black Hawk Down on Netflix right now lol.

[rcjonessnp175]

Opsec is opsec. Let's get some pretty pics of apaches in here eeeh

[EagleFox]

I thought that they are more quiet because the have more than 2 rotor blades, some body told me that (to some extent) the more rotor blades the more quiet, it's that true?

 

Nope thats not true. There is some helicoptera like Merlin that uses special ended blades which's ends don't pass the sound barrier and is a lot more quiet.

[AlphaOneSix]

It is true.

 

Blade tips don't go supersonic on any helicopter, that's really bad.

 

But anyway, in general, on the same helicopter, more blades allow you to reduce rotor diameter and blade chord and achieve the same amount of lift. Blade chord is a primary factor in blade noise, and so is tip speed, which is directly affected by rotor diameter.

[OnlyforDCS]

That is all.... Not trying to be a dick...

 

:doh:

[outlawal2]

It is true.

 

Blade tips don't go supersonic on any helicopter, that's really bad.

 

But anyway, in general, on the same helicopter, more blades allow you to reduce rotor diameter and blade chord and achieve the same amount of lift. Blade chord is a primary factor in blade noise, and so is tip speed, which is directly affected by rotor diameter.

 

And I have heard that before too. And that the rotors would explode if they did go supersonic and yet I have also heard that the Huey rotor tips DO go supersonic and the distinctive Whop-Whop sound is due to the rotors breaking the sound barrier...

 

Hmmm. So which one is true? Anyone have a definitive answer with a reputable source?

[AlphaOneSix]

Huey rotor tips can go supersonic, but that's bad, and is not the cause of the distinctive sound. The rotors won't explode, but you run into compressibility problems near the speed of sound. I'm sure you can find a definitive and reputable source to answer that if you choose to look for one.

[Bushmanni]

And I have heard that before too. And that the rotors would explode if they did go supersonic and yet I have also heard that the Huey rotor tips DO go supersonic and the distinctive Whop-Whop sound is due to the rotors breaking the sound barrier...

 

Hmmm. So which one is true? Anyone have a definitive answer with a reputable source?

 

www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA159471

 

The linked document presents two mechanisms for Whop-Whop noises. One is high-speed impulsive noise that is created with trans-sonic bladetip speeds when the flow (not rotor blade) goes partially supersonic and creates a shockwave. This happens only at high forward flying speed. The other mechanism is blade-vortex interaction impulse noise which is caused by a blade hitting the wingtip vortex of the other blade.

 

edit: Cool pictures of BVI noise: http://www.businessinsider.com/scientists-why-helicopters-are-so-loud-2014-2?IR=T

Edited February 10, 2015 by Bushmanni