Josh Babcock schrieb:
> Maik Justus wrote:
>
>> Hi Heiko,
>>
>> interesting link.
>> I think I have to improve the rotor simulation to cover rotors with
>> different airfoils along the blade.
>> But first we need the drag/lift curves for these airfoils. My short
>> search at the web was not successful.
>> I am a little bit surprised, that the ec135 uses the same airfoil than
>> the tiger. Several years ago a eurocopter test pilot of the tiger told
>> me, that the tiger is nearly not capable to autorotate. It's not
>> impossible, but he told it's rather sporty and it's not unlikely to
>> damage the helicopter. I think they want to avoid overspeed of the rotor
>> at extreme flight attitudes and therefore the rotor does not speed up in
>> autorotation. This is in agreement with his statement, that it is not
>> possible to damage the tiger while in flight.
>> But I expect the ec135 to be able to autorotate. Maybe the twisting is
>> different? (But I heard, that the enignes would be damaged, if you train
>> autorotation, and therefore the ec135 for the german Heeresflieger
>> ("army") got a modification to be capable to train autorotation).
>>
>
>
> It's a very common EMS helicopter here, and I think in Europe as well. I
> can't see an EMS agency or company buying a helo without good
> autoratation capabilities. EMS is one of the most dangerous types of flying.
>
> Josh
>
>
Hi,
I just had a short discussion with a real life professional pilot with
EC135 experience:
1. The EC135 autorotates pretty well, has a nice speeding up of the
rotor - rpm in autorotation
2. Although autorotation could be done if necessary it is not anymore in
his company due to risk of damages mainly at the Fenestron case.
The position of the Fenestron/case of the EC135 is lower to earth
compared to other helicopters and you have to do a pronounced
ground-near flare before setting the bird on ground. This implies the
danger of these Fenestron-case damages (which costs a lot of money).
3. The common meaning is that a two engine equipped helicopter with
fire-extinguishers has no high risk of being forced to autorotate
although it could be done if necessary (see 1 and 2)
4. Even in check-flights with the BK117 a real autorotation is not asked
for anymore. You have to do it "hot" (engines running, collective pitch
down) to demonstrate for your checker that you are able to select the
right place for the emergency landing and get there in the autorotation
mode but you increase collective near the ground and won't land.
Regards
Georg "HeliFlyer" EDDW
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