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Mi - 48 - physics debate
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As the previous topic on beta helicopter physics has been cancelled(resolved), and there was request to create topic about specific helicopters, here's the first one.
As a start I will put my opinion on mi-48. As it is a similar design like KA-52(coaxial) I believe there should be some advantages of this system comparing to Comanche. First few key advantages:

  • coaxial - 6-10% more efficient as compared to single-rotor
  • higher vertical rate of climb
  • lower moments of inertia
  • more stable, much better controllability

How could it be in Arma comparing to Comanche, but still remaining with some kind of balance:

  • the possibility to turn side-ways, but the turn itself would be slower, i would propose the possibility to turn 90* even at 150-170kmh(previously:200kmh), the ability to turn 180* at 100kmh, the ability to turn 45* at 220kmh(previously:250kmh).
  • max speed should be higher than RAH-99's(KA-52 max speed is around 315) - i personally propose speed of around 315-330(comparing to comanches 300)
  • it would climb faster
  • MI-48 would stop longer than RAH-99 and it would climb higher while stopping(due to wings)
  • of course due to mass, forcing a change of direction would be slower and the centrifugal force would be much higher than that of RAH-99's.


Legacy ID
Steps To Reproduce

Community propositions:

Additional Information

Great lecture is DCS - Black Shark manual, from page 65.
Comanche issues:

Event Timeline

Byku edited Steps To Reproduce. (Show Details)Jul 16 2013, 7:23 PM
Byku edited Additional Information. (Show Details)
Byku set Category to Balancing.
Byku set Reproducibility to N/A.
Byku set Severity to None.
Byku set Resolution to Fixed.
Byku set Legacy ID to 3221101656.May 7 2016, 3:31 PM
Bohemia added a subscriber: Dombl.Jul 16 2013, 7:23 PM
Dombl added a comment.Jul 17 2013, 4:39 PM

The Ka-50 flight manual from DCS says weathervaning starts noticeably appearing around 90-100 km/h, and to let the aircraft turn itself around if you reach those speeds tail first. It specifically states that as the maximum speed for tail first flight without altitude loss, and has some poorly elaborated bits about the nose tilting down during the induced turn.
In short, I'd say a 180 degree turn at that speed might be a bit much, but it could be good starting point for turn limits.
I am assuming the Mi-48 is quite a bit less aerodynamic than the Ka-50, so turn limits would probably be lower.

For max speeds, the Ka-50 has it around 300, going lower with altitude and loadout weight. We don't really have to worry about altitude for now, since Arma 3 takes place at sea level, but co-axial configurations have a pretty sharp speed limit since the upper and lower rotors collide if you go too fast or make harsh manoeuvres close to max speed.
I had expected the Ka-52 to have lower max speed due to higher weight, but I can see a great many things affecting that, like rotor spacing and lift from the aircraft body.
I am unsure if we should go with those limits, since I don't think the more gradual problems at speed (dissymetry of lift and retreating blade stall) for single rotors are simulated.

Would you mind giving sources for the speed figures you have? I only really have the flight manual to compare to, and those figures probably have safety margins added.

Byku added a subscriber: Byku.May 7 2016, 3:31 PM
Byku added a comment.Jul 18 2013, 5:11 PM

To be honest, tried in-game at altitudes of 250-500 and through reading on different sites(wiki,defence journal and some others). Sure i had some warnings ;), but i suppose 20 years from now they will improve the technology, so 330 in level flight won't be a problem. Yes, I agree with the fact that MI-48 looks like a lot less aerodynamic that Ka-50 so... hmm... maybe 90* at 150/160 might be enough, with 45* at 220/240.

oukej added a comment.Sep 3 2015, 5:49 PM

Better simulation was achieved with the Advanced Flight Model implementation.