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[konaone]

Friends, those who want to do this :

[Uriah]

I've had my eye on the S-97 for quite some time, and have considered taking in on as a project. I don't have much free time these days, and I have a backlog of work and projects to take care of first, but it is something I'm very interested in. On the flight model side, that is something I could build in a couple of days. The flight model is actually much simpler than a traditional helicopter because of the ridged coaxial rotor system, and the separate lift and thrust push prop configuration.

There are two problems I see with it as a project. First of all, the S-97 isn't an operation aircraft, and therefore I have been able to find very little data to build an accurate flight model. The second issue is that since it is a demonstrator, the cockpit is extremely sparse and wouldn't be very interesting, although easy to model.

I found a free 3d model on TurboSquid, (very poor quality so don't get your hopes up), and I might import it to OT and build a flight model for it, but I don't think I'll get around to building a detailed model any time soon.

Best regards,
Uriah

[konaone]

It is an interesting model and I think it can also be fun to fly.
Very maneuverable, if what you see in the preview corresponds to reality.
The model turbo squid is actually poor, but initially ..........
Unfortunately I learned to model with 3ds max, although I would very much !!

[PytonPago]

Seems Sikorsky is giving a shot for the Kamov-"patent" design for doubble-blades. Yet, how much speed can that keep ? ....  i mean, wouldnt it stress the rotor too much if the back-propeller gives too much power ?

[Uriah]

The S-97 uses a ridged non-flexible rotor system, and based on what I have read the rotor blades don't flex almost at all, so there is almost no flapping moment, even with high forward airspeed. This takes full advantage of the Kamov design to avoid retreating blade stall pitch moments, due to gyroscopic precession of a 90 degree out of phase stalling blade. The S-97 RAIDER will take the record for fastest military helicopter, with a cruise speed of 253 mph; 407 km/h (220 knots), topping the CH-47F Chinook's previous military helicopter cruise speed record of 196 mph; 315 km/h (170 knots). The fastest helicopter in the world is of course the Sikorsky Eurocopter X3, at 293 mph; 472 km/h (255 knots).

Below are some screenshots of the S-97 I imported for Outerra. I only spent about an hour on the flight model, so it isn't accurate at all yet. I'll release it once I finish the flight model and find time to model the cockpit and landing gear.

Regards,
Uriah

[PytonPago]

No flex ? ... i can hardly imagine that ... or they will probably have to change them a lot due to structural material wear.

[HiFlyer]

Ghost wheels!!

Beyond that, it looks pretty cool. 

[foxfiles]

The fastest helicopter in the world is of course the Sikorsky Eurocopter X3, at 293 mph; 472 km/h (255 knots).

You mean the EUropean Eurocopter X3, which is not US Sikorsky...
BTW Eurocopter changed its name lately and it is now Airbus Helicopters I think. Anyway X3 is a only demonstrator and unfortunately it does not seem that this program is moving a lot : our European Defense (and all the rest) has his pockets empty, LOL

X3 is an old concept that was revisited, with 2 flying modes : full helico or sort of gyroplane with 2 propellers pushing in horiz flight. Some say that the lateral rotors are "annoying" => dangerous zones, difficult for the passengers to come onboard and so on, and it is quite true.

[Uriah]

Thanks for the correction! :-)

I can see how the laterally offset propellers could present issues for an operational helicopter which is probably why the X2 and S-97 opted for the aft push prop and coaxial rotor. I can see why they choose that configuration for the X3 though, because yaw is controlled by differential blade pitch of the right and left propellors.

Regards,
Uriah

[foxfiles]

Thanks for the correction! :-)
I can see how the laterally...

You are right, it would be cool to know the real capacities and flight-enveloppe(s) of these machines, to compare...
Humm your comments indicate that you're quite skilled in these topics

I don't know why Eurocopter followed the 'gyroplane' route but what is sure is that they tried to reduce the costs in using on-the-shelves componants from their other choppers. Maybe a bit less innovative approach than the Raider...
It's quite funny that they both used the X letter, X2 at Sikorsky and X3 at Eurocop, they could have been a bit more imaginative.

Both are impressive machines.

[Uriah]

Finding accurate data on these issues very difficult because there is little to no technical documentation available.

X stands for experimental, and they were part of a competition if I remember correctly. Like the competition between the YF-23 and YF-22.

Regards,
Uriah

[PytonPago]

Not sure, how much the back-prop influences the airflow dynamics, but im convinced its still the same coax basics with just a little forward push and lift loss if you ower-power the back-prop (taking the air from underneath the back part of the rotor), maybe this helps a little :

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19970015550.pdf


 ....  i like this kind of papers.

[konaone]

Someone working on the model for Arma 3:   https://forums.bistudio.com/topic/183239-sikorsky-s-97-raider-early-wip/

I'm looking for more detailed information on the size and blueprint, where there is the landing gear. Maybe soon

[MrWohoo]

Not sure, how much the back-prop influences the airflow dynamics, but im convinced its still the same coax basics with just a little forward push and lift loss if you ower-power the back-prop (taking the air from underneath the back part of the rotor), maybe this helps a little :

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19970015550.pdf


 ....  i like this kind of papers.

As a man who have limited mathematical knowledge, this hurt my head just lookin at it