Re: Rockoon Launch
- Just remember the atmosphere at 100kft is about the same as Mars, in order for us to fly at that altitude the rotors had to be designed after the blades of the Helios aircraft NASA flue at 96,000 ft. They are very thin and ultra light weight. Motors cant dissipate heat very well either at that altitude.
For a return autorotating does work! A tri-copter could autorotate during the decent and if you swing the motors/rotors 90 degrees it could fly like a plane in the lower atmosphere with the front two rotors pulling and the rear one pushing.
--- In firstname.lastname@example.org, Scott Miller <scott@...> wrote:
> I know helicopters have at least a limited ability to land using
> autorotation in the event of a tail rotor failure because of the very
> low torque. I would expect that friction is still going to try to turn
> the payload, but maybe a big fin would be enough to slow it down to a
> controllable state. Or maybe counter-rotating rotors on the same shaft?
> It seems like it ought to be easier to deal with than a glider, and
> simpler than a helicopter since it doesn't need to transmit power
> through the shaft.
> In any case, it's going to be a long time before I have time to mess
> with a new project like this.
> In the shorter term, it'd be fun to design a long-duration lander. The
> last payload I flew out in the desert landed on the side of a mountain
> in the middle of nowhere, with good APRS coverage. If it had been
> weatherproof and solar powered, it could still be out there sending back
> telemetry and the occasional JPEG image trickled out a packet at a time.
> On 5/9/2011 10:40 AM, pb648174 wrote:
> > Well, with just an autorotating helicopter blade your payload will be
> > spinning in the opposite direction just as fast and probably not very
> > controllable. So you'd need a tail rotor and once you do that you've got
> > a helicopter. To get an idea of the difficulty of controlling that go to
> > the local RC store and try out the RC simulators which have a helicopter
> > option. Helicopters are very difficult to fly even in a slight wind,
> > much less 100mph.
> > So I would think for any kind of option like this you'd want a full UAV,
> > either a glider, powered airplane or tri/quad copter. That stuff is cool
> > and fun and can be tested on its own minus the balloon so I would think
> > that is the way to go. There are lots of arduino based UAV projects out
> > there to look to for inspiration.
> > --- In email@example.com <mailto:tracker2%40yahoogroups.com>,
> > Scott Miller <scott@> wrote:
> > >
> > > > Any non-powered descent device is going to have a very hard time
> > > > penetrating the high speed winds encountered during ascent. Gliders,
> > > > steerable parachutes, or whatever else you dream up would need to have
> > > > a glide slope and forward speed that averages high enough to overcome
> > >
> > > Are there any resources out there on guided landing systems? I was
> > > thinking about trying some sort of autorotating helicopter blade for a
> > > balloon payload. It wouldn't be for returning to the launch site, just
> > > for choosing a landing site within a certain range.
> > >
> > > Scott
> > >