Saturday, November 3, 2012

Propellers In Space

The Shuttle had wings to fly its way to a soft landing on a runway.  So wings were used in the Earth's atmosphere to help spacecraft operate.  What if rotary wings could do something similar?  The first commercially successful rotary wing craft were De La Cierva's autogyros.  The autogyro works on the principle of auto-rotation.  Therefore, it can make safe unpowered landings.  A helicopter works on the principle of powered rotors which allows it to take off vertically.  A rocket lifts off vertically and its capsule lands with parachutes in a vertical fashion.  So you see mixing these technologies together may not be so far fetched after all.  Let's look at a couple of projects.

NASA's Roto-Capsule concept

NASA put out the news report entitled Engineers Test Rotor Landings for Capsules. Apparently the Roto-Capsule (I just made it up), uses auto-rotation like an autogyro does.  They also want to figure out how to get the rotors to start spinning.  In old and small autogyros, you hand start the rotor spin.  Yep you have to use those mittens, and don't stand up too tall or you might get whacked by a blade.  The larger and enclosed autogyros use a bendable drive train from the engine to the rotor hub.  I suppose NASA could start the rotation of the Roto-Capsule's rotors with simple thrusters or even with an electric motor.  I'm sure they can come up with better ideas than I can.  They do have to figure out what the best solution is, what is the lowest weight for a system, how strong is it, and what are the operational costs to it.  Looking at the picture, I can't help but wonder if this is an excuse to get scientific data form the engineers propeller beanies.

Another project was, if you can believe it, a rocket with rotors on the top.  It was called Rotary Rocket.  Apparently its rotors were also for landing.  The concept was revolutionary for its time; late 1990's.  It was touted as a single stage to orbit.  It went as far as a demo vehicle that flew with powered helicopter rotors.  There were aerodynamic problems with it, but an arial test vehicle was made and flown showing that rotors could lift the rocket.  It was almost sad to see this project die, but I think they put too much in the concept.  I mean, why would you want to use rotors to land a rocket?  Wouldn't the rotors be useless weight for most of the flight?  You can say that wings are too, and they are.  Rockets would be less overhead weight as far as hardware because you need to rockets to launch as well as land.  I suppose the argument is how much extra fuel your willing to take on a flight.  That's where the weight trade off is.  Rotary wing craft are what we have that closest behaves like a small space ships in sci-fi fiction in atmosphere; they land and take off vertically. I guess sometimes we can dream too big.

In my own muses, I thought if we can air launch a rocket to orbit with a plane, then why not with a rotary wing craft?  The craft would have to be very large though.  It would have to be custom made to lift vertically to altitude.  It would have to be a separate vehicle from the rocket.   I imagined it being large enough to fit the rocket in the middle of it and launch at altitude in a vertical attitude.  The savings would come with launching from altitude in a vertical position.  It does seem superfluous though.  Stratolaunch is making the largest plane to launch a medium size rocket from altitude.  The plane will probably need the biggest of runways.  That's where my rotary wing craft could come in; in scaling up.  I wouldn't need a runway, just a pad.  That's less ground infrastructure than a plane.  These are just muses though;  ideas of runaway imaginations.  Rarely does a dream come to life.  I'm glad of that, cause I've had some nightmares.

So we looked at a couple of projects that involved rotary wings and space craft, and then one of my imaginations.  That's what your going to get when you read my stuff.  I just scrape things off the wall.  Is it really a good idea to mix rotors and spacecraft?  Maybe, but also maybe later.  We still have a lot to learn about launching stuff into orbit on a shoestring budget.