Even the pros put their blades together

but if you catch one (and down it) while it was hovering at 20 meters AGL the crew are better helped by the cockpit design than an ejection seat?

I personally watched an AH-64A drop out of a hover like a rock from 50 feet (close to 20 meters) and it hit the ground*, broke off the tail boom, and dug up a bunch of dirt. Shortly thereafter, both crewmembers exited the aircraft, relatively unharmed. There is also the famous first crash of an AH-64A in Albania in the 90's due to settling with power from a hover. One of the pilots broke a finger. The aircraft is designed to keep the crew alive at up to an impact at around 50 feet per second (15.2 meters per second) crash, as long as it lands "feet first".

*The aircraft had a tail rotor failure at night wjile hovering just off of the airfield, with a brand new pilot at the controls. Normally, loss of tail rotor authority is countered by a reduction in power to prevent extreme yaw, but from the hover, this was no the best idea. Before the instructor could take over, the aircraft had crashed.

Very interesting.

As a followup question, in your understanding, is there a fundamenal doctrine difference in the use of attack helicopters between the US and Russia (or well, the Soviet Union since that's the regime the Ka-50 was designed in) that would directly explain these differences?

EDIT: That said though, on the note of the coaxial design being "nuts", I again ask how many tail rotor failures the coaxials have suffered. :P

Very interesting.

 

As a followup question, in your understanding, is there a fundamenal doctrine difference in the use of attack helicopters between the US and Russia (or well, the Soviet Union since that's the regime the Ka-50 was designed in) that would directly explain these differences?

What differences? The vast (and I mean VAST) majority of helicopters in the world do not have ejection seats. I think the addition of an ejection seat to the Ka-50 was a novel idea and mostly a marketing move. If it's such an awesome idea, why don't more helicopters have one? Personally, I think it's great, but I don't see an ejection seat as any kind of difference in doctrine. Of course, there is a big difference in attack helicopter doctrine between services in the U.S., to say nothing of the differences between the U.S. and the former Soviet Union.

EDIT: That said though, on the note of the coaxial design being "nuts", I again ask how many tail rotor failures the coaxials have suffered. :P

Can't argue with that statistic, but it does beg the following two questions: First, just how common are tail rotor failures in single rotor helicopters (note that the loss of tail rotor authority does not guarantee a crash)? Second, if coaxial rotors are the best design, why is it that only one design bureau in the world makes them? Don't get me wrong, I like the Kamov design very much, but if that design was really the best, we'd see many more of them (and maybe we will in the future as technoliogy advances, e.g. Sikorsky X2).

Can't argue with that statistic, but it does beg the following two questions: First, just how common are tail rotor failures in single rotor helicopters (note that the loss of tail rotor authority does not guarantee a crash)? Second, if coaxial rotors are the best design, why is it that only one design bureau in the world makes them? Don't get me wrong, I like the Kamov design very much, but if that design was really the best, we'd see many more of them (and maybe we will in the future as technoliogy advances, e.g. Sikorsky X2).

Probably comes down to cost vs effectiveness..

There are many advantages with the co-axial design over the conventional but the conventional design would be a whole lot cheaper to service/maintain..

There is ALWAYS an accountant involved and they look at spreadsheets...

e.g- Is it worth spending another 2 million per AH-64 to save maybe 20% of downed apache pilots???

*edit- I know this may sound like a blunt opinion but there is an element of truth to it..

Plus..-.. as mentioned in this thread quite high survivability rates in such aircraft as AH64, ejection seats are not feasible, as nor some sort of rotor governing system on a KA50... :P

Alpha, I don't know the numbers on relative safety, as before the tailrotor discussion is just a pointer to the the facts of how this discussion got going. It is patently impossible to confidently state that one configuration is safer than the other without some data, and people tend to exhaggerate the dangers of the unusual and forget the dangers of the usual. (More people die from falling coconuts than are killed by sharks, but we don't see people worrying about the coconuts... Or, for that matter, the comparative safety records of riding a bike across town and flying over town for your sight-seeing. The latter is safer, but it's unusual, and therefore people worry. )

In the case of conventional versus coaxial, if I were to guess (since I don't have data either) I would say that conventionals are probably easier to construct and would have a slightly better safety record, but I personally would say that the coaxial design's advantages would outweigh - insofar as I understand them. (Fuel economy, service ceiling, airframe size etc.)

But that's a personal preference.

I think, such questions, like "which concept is the best" will always cause endless discussions with no final answer. Which does'nt mean that it should'nt be discussed, though.

Every construction has its' advantages and disadvantages. Take the delta wing-design of the Mirage, for instance. This design makes faster planes (at same thrust) but suffers of low speed-agility. The Eurofighter went a step further and added canards which increases its' agility, although a delta wing-design. The tri-plan-construction of the SU-30M/33/37 series gives the plane more agility and lower take-off and landing speeds. However the new SU-35 does'nt use canards anymore. You see, even within the same company and aircraft family they flip from one solution to another.

I'd like to call this "evolution" as it is with animals and plants. There will never be one ultimate solution for everything. Otherwise only one species would have had survived. This keeps things very interesting and we will still be able to chit-chat about which is the best plane in the world :smartass:.

Cheers,

Endo

Actually delta-wings have great slow-speed, high-AoA handling ...

And the canards were removed becauset here were other ways to get agility on the 35, therefore the extra weight, drag, and wiring was not warranted. ;)

Actually delta-wings have great slow-speed, high-AoA handling ...

 

And the canards were removed becauset here were other ways to get agility on the 35, therefore the extra weight, drag, and wiring was not warranted. ;)

Well, there I've heard something different. But I'll search for some more information.

Was there not a post not so long ago that questioned the In-Game Propensity of the Kamov to explode when contacting the Ground?

 

The Question has been Answered it would seem........

I wondered about this myself.. are the ground contact explosions

overdone in BS?

:huh:

btw, the more I fly the less problem I have of blades colliding,, in fact, very, very few times I ever do that,, it's been a very long time since my blades hit each other..

only time they may is in a bad landing.. on uneven terraain,, and even then, they probably didn't hit each other, they probably hit the ground from a bad tilt to the ground...

How about a ducted fan being run by a THIRD engine (Either a very powerful APU or another entirely new helo) to replace the tail ala X-49A Speedhawk.

Harder to truly damage the device counter-acting the torque, more engine power, more range, more payload, and you don't risk hitting the fan.

Not to mention, you fit longer wings, so for the attack helos that's two extra hard points.

Either 38 more Hydras, or 8 more Hellfires. For Cobras/Apaches your loadout would be:

8 Hellfires, 76 Hydras

16 Hellfires, 38 Hydras

24 Hellfires

152 Hydras.

Sure sounds nice...

That, and even if the controls via ducted fan fail, the stub wings have ailerons.

I guess one problem with computer limited envelopes would be if something was to push the system outside of it's normal parameters, such as damage to a blade affecting it's lift. Perhaps that could even cause a crash as the pilot would not be "allowed" by the computer to get enough cyclic to say stop the aircraft rolling.

I guess one problem with computer limited envelopes would be if something was to push the system outside of it's normal parameters, such as damage to a blade affecting it's lift. Perhaps that could even cause a crash as the pilot would not be "allowed" by the computer to get enough cyclic to say stop the aircraft rolling.

FBW like the Airbus systems is bad.

Something assist with stability ie your helo will stay at the proper angle and stay trimmed for a certain condition for whatever the case (hover), with no pilot intervention. Pressing trim no longer means keeping recentering the cyclic, it means keeping the exact same rate of climb, rate of turn, and speed.

Hunt3r, what you are talking about there is pretty much an autopilot. The Ka-50 has one of those. ;)

It may not be allowing the exact settings you are asking for there, but on the other hand it doesn't really have to. Rate of climb? Just trim and set collective. Rate of turn? Just trim...

Hunt3r, what you are talking about there is pretty much an autopilot. The Ka-50 has one of those. ;)

It may not be allowing the exact settings you are asking for there, but on the other hand it doesn't really have to. Rate of climb? Just trim and set collective. Rate of turn? Just trim...

Well that's basically what I'm driving at.

But after you trim, the helo will basically be in AP, and holding your flight parameters. Completely hands off.

If when you trim the rate of climb and speed is zero, you now have a nice hover.