eric_b
Veteran
Location: Denver, CO, USA
| Well, I can comment on my experiences with the R-Max.
1. Blade icing.
Probably not an issue with blade icing. But it has been shown that the R-Max is prone to carb icing in the right (wrong?) conditions, which kills the motor. Since the thing cannot autorotate, it will plant itself. If it's fully loaded with avionics, then it will just plant itself deeper.
2. Electronics performance in high humidity, freezing conditions.
I think most of the Yamaha electronics are rated at 95% rh, non-condensing, although the enclosures are only rated drip-proof. Thus the avionics we installed also met those criteria. We conformally coated the boards. I'm pretty sure there were days it got to 95% humidity - didn't have any problems in that concern.
3. Ability to fly in winds to approx 45mph.
The R-Max can only safely handle winds at about 20mph if very lightly loaded, and less than 10mph if heavily loaded. Otherwise the head dampening is sketchy, and it will probably boomstrike.
4. Altitude performance of turbine vs. gas motor.
The R-Max engine is underpowered in comparison with other similar sized UAV helis. If loaded to Yamaha's stated gross weight, it can only safely fly at density altitudes <2000-2500' max, which is basically sea-level on a mild day. I can attest that with the recommended fuel, the R-Max will overheat and vapor lock if pushed hard at higher density altitudes, even at below freezing temps.
For something else that comes closer to meeting your requirements, have a look here.
I'm currently working with a turbine Industrial Bergen, which is flying a bare UAV to payload weight ratio of about 1:1, flying at 10,000' DA with no problems. (The bare R-Max UAV to payload ratio is a portly 4:1, sea-level only) The DA changes don't affect turbines as much as piston engines, as small changes in barometric pressure don't affect the overall "compression ratio" of the turbine as drastically as with a piston. |
