Rocket Racing League First Exhibition Race August 1st and August 2nd, 2008

On Tue, 1 Jul 2008 14:55:40 -0700 (PDT), BobR wrote:

Not sure why everyone keeps making the comment about dead stick
landings. Rutan demonstrated the rocket plane at Oshkosh a couple of
years back with the full ability to start, stop, and restart the
engines.

When Rutan flew, he was the only plane up there. When he hit the "go" button,
all he was expected to do was fly around the airport at least once, then land.
He could keep some fuel back in case he had to go around, or "blip" the rocket
to correct for an undershoot.

In contrast, of course, the RRL pilots will be busy flying the invisible course
and keeping from running into up to nine other rocket planes. It's a little
different problem....

According to the RRL web page, they're going to stagger the takeoffs, so that
should reduce the chances for simultaneous deadsticks. However, it's going to be
interesting if (for instance) a landing gear collapses and the plane stops on
the runway. I'm sure they'll have a backup runway, but the guys aloft may have
to scramble a bit. Trouble is, unless there's a second backup runway, racing
will have to stop until they get the primary cleared.

I surfed around the RRL web page, and found some technical data that I hadn't
noticed the last time I checked, several months back.

"...1,500 pound thrust rocket engine burning liquid oxygen (LOX) and kerosene...
Each X-Racer will be a single-pilot vehicle with an empty weight of roughly
1,000 lbs and a propellant weight of 1,000 lbs..."

Lox/Kerosene has a Specific Impulse of about 300 seconds, so this comes out to
200 seconds of engine run time (web page says 4 minutes of intermittent powered
flight, so that ties in). Ten minutes of glide time, Pit times are listed as
5-10 minutes. So that makes less than four minutes of powered flight per
aircraft every twenty to twenty-five minutes.

"...the Rocket Racing League will feature multiple races pitting up to 10 Rocket
Racers going head to head in a 4-lap, multiple elimination heat format on a
5-mile "Formula One"-like closed circuit raceway in the sky."

It's a twenty-mile course (five miles around, four laps). The planes should be
able to complete the course WITHOUT a pit stop...the plane has to average just
80 MPH during that 15-minute flight.

However, the web page says they have to pit after "3-4 laps." They may be
requiring some sort of fuel reserve. But it seems weird to plan for a 5-10
minute pit stop when the plane could practically *coast* around the course for
that last lap. My guess is that the "pit stops" are more to get planes ready
quickly for the next heat before the spectators wander away.

Still didn't' find anything on the web page about flight altitudes. It might be
something they leave up to the teams to decide...either go up high and coast
downhill at high speeds, or stay low and run the engine in short blips.

Ron Wanttaja