Re: Trex 450 Autorotation
- From: "Steve R" <srhodes13@xxxxxxxxxxxxxxxxxxxxx>
- Date: Tue, 8 May 2007 08:42:29 -0500
Yeah, what he said! :-)
-10 degrees is WAY too much. -4 to 5 should be a maximum I would think.
The little birds simply don't carry the rotor inertia that the bigger ones
do so autos will always be problematic on them but they can do it if needed
and the pilot keeps his act together.
As far as rpms go, don't think that just because you're running 3000 rpm in
powered flight, that that's what you're going to get in autorotative flight.
Measuring autorotative rpms in something like a T-Rex would be almost
impossible. Things just happen too fast. I can tell you that, regardless
of how fast you're turning that 30 to 60/90 size bird in powered flight,
once you enter the autorotation, you're going to be down around 1450 within
the first 3 to 5 seconds. We've tached about a dozen different models and
this worked out to be the case no matter what. We had a 60 size bird
spinning between 1950 and 2000 rpm, flipped throttle hold and they hadn't
dropped 10% of their altitude and the rotor stabilized at 1450, give or take
a little depending on where the pilot was holding the collective. I can't
imagine that the micros are doing much better.
"The OTHER Kevin in San Diego" <skiddz "AT" adelphia "DOT" net> wrote in
On Mon, 7 May 2007 09:39:04 -0400, "Larry" <me@xxxxxxx> wrote:
Has anyone ever had a successful autorotation with a Trex450 with wooden
blades (335mm). I an use to larger 60 size helicopters and have been
successful with them (Lot of energy stored in that rotor). I try with the
Trex and it just drops like a rock and loosed rotor speed almost
immediately. I just power back up at 25 feet and just about miss the
ground. I hope I never need to do one in a situation where I can't turn
the motor back on. Any advice would be helpful.
Forward speed and not too much negative pitch. Too much negative and
you're adding drag to the blades. Forward speed will "bank" energy
you can use for the flare and setdown. Dropping the nose will kill
your RPM. Keep the nose up but not so far as you kill your forward
The harder your flare at the bottom, the more you'll load up the head
and generate from "free" RPM. Just don't balloon when you flare..
Pull the nose up to stop the descent and then bleed off speed while
paralleling the ground. Once you're almost stopped, level the skids
and feed in the collective to cushion the landing. You're going to
need to be less than 2' off the ground at the end of the flare or it's
gonna drop to the ground.
What's your headpseed in a hover? If you're running low-mid 2000s,
you're "behind" the curve for autos in a small ship like this. 450s
are hard to auto, but if you get the headspeed up near 3000 RPM you've
got a bit more energy stored before you enter the auto.
- Trex 450 Autorotation
- From: Larry
- Trex 450 Autorotation
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