Tail Rotor Power Consumption

[IFMU]

Originally Posted by NickLappos

The pursuit of symmetry that is his mantra seems to be sparked by some internal asymmetry, frankly! Even Charlie Kaman, the inventor, dumped the syncropter configuration that Dave is wedded to, Dave has never tried to find out why.

So why did he dump the syncropter? It appears they put the Seasprite up in front, at least in terms of the picture coverage. It also seems they build blackhawk cabins:
http://www.kamanaero.com/images/PDFs...20Sikorsky.pdf

The K-max is still there, looks like it can lift a decent amount but you could just about catch it with a S300CBi.

-- IFMU

[Dave_Jackson]

IFMU,

About a year ago Kaman mentioned that they would not be producing any more K_MAX's and that they were trying to sell the two that they were leasing out; as I recall.

They plan to stay strongly in the helicopter industry, but as a component manufacturer and not as a complete helicopter manufacturer.

Charles Kaman's failing health may have something to do with this.

Dave

[Cyclic Hotline]

The end of the K-Max has been driven by the horrifying accident rate.

http://www.markusherzig.com/kmax/

I'll let you interpret the data yourself!

[HELOFAN]

Though most of the Kmax isues look to be pilot error, hitting trees, shutting off fuel accidently etc.

The splines houseing issues are a concern.

So it seems if that the drive from the engine is lost Rotor RPM decays very quickly or would that be from the material breaking up and causing drag?

Most likely the latter I imagine though reading the reports the RRPM drops quickly doesnt it.

Are they stopping producing the Kmax then?

I dont really see why, I dont think that is it a design issue though they dont have that many aircraft produced and have quite a few destroyed.

Interesting sites.

HF

[NickLappos]

I doubt that the configuration has anything at all to do with the accident rate, but the mission (long hours hovering OGE close to obstructions) is certainly a difficult one.

I don't know why the synchropter config was not used for the later Kaman airfraft designs, which were naval shipboard aircraft ostensibly well suited to the syncropter design. If we are saying that Charlie Kaman dropped the syncropter from his bag of tricks, does that mean Dave must add him to Dave's private list of "Designers who don't know what a GOOD helicopter looks like"?

[Dave_Jackson]

Nick;

Perhaps the teetering rotor is slowly being replaced by rotors with greater control authority. Thereby relegating this simpler and lower cost rotor to the recreationalists, in a manner similar to that of the gyrocopter.

Kellett wanted to produced a rigid 3-blade intermeshing helicopter many decades ago.

Dave

[Cyclic Hotline]

Though most of the Kmax isues look to be pilot error, hitting trees, shutting off fuel accidently etc.

The splines houseing issues are a concern.

So it seems if that the drive from the engine is lost Rotor RPM decays very quickly or would that be from the material breaking up and causing drag?

Most likely the latter I imagine though reading the reports the RRPM drops quickly doesnt it.

Are they stopping producing the Kmax then?

I dont really see why, I dont think that is it a design issue though they dont have that many aircraft produced and have quite a few destroyed.

Interesting sites.

HF

They stopped production of the K-Max some time ago. The future of the aircraft will be dictated by the limited parts inventory at hand. Other issues included high acquisition costs, single engine operation in the operating environment they specialize in (dependent entirely on your point of view), and the extremely high insurance costs driven by a helicopter with a 42% loss rate - something that is incomparable in the helicopter business, or maybe even the entire aviation business.

The K-Max is not a bad machine, in fact it is very good at what it does. It is phenomenally slow however. There is also a very limited market for helicopters that only perform external load operations, as the Skycrane also found out when compared to a Chinook (oops, another dual rotor reference).

The facts above provide a pretty fair explanation as to why the K-Max has a limited future at this time, not to say it won't get ressurected in the future, perhaps by someone other tham Kaman even!

[old rotorman]

X49-A update.
This program still being funded. The aircraft has accumulated about 70hrs and is now undergoing an annual inspection. Testing will strart up again next month.

[AdamFrisch]

Tail rotor power?

What would you say, in percentage, was the power the tail rotor steals from the main unit when used to full right pedal?

[deeper]

Seventy eleven percent at least from the main unit and eleventy nine percent from each and every one of the other secondary units and none,nil,nada from all third and fourth units exept on odd days. On these days it is best to stay in bed with your wifes sister and not fly.

[WhirlyBob]

Merits of rotor configurations

What would you say, in percentage, was the power the tail rotor steals from the main unit when used to full right pedal?

I'll make a leap of faith and take it that you really mean "when the tail rotor is producing maximum thrust to counteract main rotor torque" since the answer would otherwise depend on whether you're talking about a Eurocopter, which spins the main rotor in a direction that God never intended, or say, a Bell or Sikorsky that turn the main rotor in the proper manner.
But with that nit picked, I offer this quote: "Tail rotors typically consume up to 5-10% of the total power" ... click here for source document

This is from a helicopter aerodynamics course taught by Prof. J. Gordon Leishman at the University of Maryland.
The complete document is an interesting although fairly brief discussion of "conventional", tandem, and co-axial rotor configurations.

[topendtorque]

On these days it is best to stay in bed with your wifes sister and not fly.

Which goes to debunk the old adage that Helicopters are inherently dangerous, it's really the pilots.

[Dave_Jackson]

Leishman's recent papers are devoted to the coaxial configurations.

A quick overview of Tail Rotor Power Consumption