High speed pass (without a piston engine).

Didn't want to hijack Aircooled's thread.  I love the sound ! 

The mist you see is water, the wings are filled with water to get more speed from one thermal to the next.  They're dumping the water.

I'm always happy to see your posts about gliders. I especially enjoy the videos. 
 

Could you elaborate a bit on the principle of putting water in the wings?

I mean, if were talking about fast gliders,  mach 25 is pretty fast.

In reply to 914Driver :

Very cool to only hear the aerodynamics!

The fact that you are hearing anything implies inefficiencies (whistling requires turbulence) but of course in those passes the glider are WAY past their optimum glide speeds, where I am sure they are very quiet.

This is one of things that if they depicted it in a movie, the would likely come up with some ridiculous whooshing sound or something.

I suspect the ballast is also used to make them more manageable in high lift situations like heavy thermals, maybe ridge soaring?  It will increase the obvious wildly low wing loading and make them "ride" much smoother.

In reply to Appleseed :

Well, I mean, technically, a rock is a glider also, just a very bad one 

This was also a glider though.  They could steer it on re-entry and could actually (and did) go into a climb!  At very high speeds of course.

In reply to aircooled :

I had no idea a reentry capsule was steerable. I figured once initiated, you were on a parabolic arch. You were going where you were going.

BTW, I got to see Apollo 8 yesterday, the first manned object to leave Earth and visit another celestial body.

Cumulus clouds are big puffy cotton ball looking things, they are at the top of a column of warm air rising up.  Get between the cloud and the ground and it's an elevator ride up (my gage tops out at 1,000 ft/min.).  Just toodling around, speed isn't important, but racing?  They assign turn points based on weather conditions that day, it's a timed event.  

If lift is strong enough to get your ship +8 lbs/gallon, at the top of the thermal you let gravity take you to the next one.  More weight = more speed.

You take off, a clock starts and you head out, climb up a thermal and at the top (cloudbase) you head for the next thermal.  If you get there faster than the next guy, you're in the lead.  If conditions dwindle, lift diminishes, you dump the water.  Less lift won't get all that up to the top.

At the National level or International level, the name of the game is follow the leader.  Like watching sailboats on a lake, the guy on your left is rail down, guy on you right is luffing the sails, you go left.  Once at a Regional event, the leader got tired of pointing the way for the others, so he climbed to the top and dumped his water!  Thermal disappeared, everyone scattered.

He won.

This is a "cloud street", clouds line up in a row; you tuck in and cover  lot of ground without twirling around.  We get that a lot locally because of the mountain ridge west of me.  The more the lift, the faster you can go without losing altitude.

In reply to 914Driver :

So, is there a defined "race" here?  E.g. what defines the finish line?  Which of course is hard to do since the course keeps moving!

I guess you could use: he who has the most altitude at the end of a defined time, but with the performance of some of these gliders, the pilots would probably need pressurized suites!

Appleseed said:

I had no idea a reentry capsule was steerable. I figured once initiated, you were on a parabolic arch. You were going where you were going.

The Mercury and Gemini capsules were fully ballistic with no steering capability -- that was a new tech introduced with Apollo.

Columbia (Apollo 11) in DC:

aircooled said:

In reply to 914Driver :

So, is there a defined "race" here?  

Timed event.  They have a pilots' briefing (Drivers' Meeting)  to explain the conditions and turn points.  You take off and the start is over a line at a specific altitude, then you go to the turn points.  In the old days, pilots carried a camera to document hitting the mark, now with GPS is easier and folks on the ground can keep up with the progress..

Smaller, slower gliders start first.  There are classes according to wingspan; Vintage class,  15 meter, 18 meter etc.  Both of mine are 15 M. (~49 ft.)

This is a sample of a course.

There are some very good flight simulators out there.  Pick a venue, choose the ship and conditions and go practice.  You can compete on line but venue and conditions are set, and the images are very good.

My heavily modified Libelle 301.  Stock is 28:1 glide ratio Mods make it a 40:1.  

DG-300 that I brought to a high school for science class show & tell.  42:1 glide and VERY comfortable.  Teenagers climbing in and out all day, one even pulled the canopy eject on me.

  =~ 0

Appleseed said:

I mean, if were talking about fast gliders,  mach 25 is pretty fast.

Given that thing's glide ratio, you're stretching the definition of "glider"...