da Rock
Posts: 7007
Joined: 10/11/2005
From: western,
NC, USA
Status: offline
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Kewl narrative...... Keep up the good/brave work. You've braved it out and done all the sensible things and discovered that what you thought would work did.
About bungee launching....... The important detail pertains to the location of the towhook. The location of it will do more to decide how stable or twitchy the launches are. It's location is relative to the CG location and since you've balanced the CG to the plans, then the plans location for the hook will be safe enough.
Most gliders will take all the force you can walk back into the rubber. That force isn't exactly what an experienced glider guider would do on the first launch however. As with everything, you have to have the right technique, and you learn that by doing. So hook up the glider and walk back some. Watch the string and the rubber. When you've got them both off the ground, ask yourself if the pull is about 3X the weight of that glider. grin..... Of course, who can feel if a horizontal pull is like 3x the vertical pull..... If you think you can pull more then do it. When you've gotten back so far that the pull scares you, then walk about 1/4 the way back to where you first made a pull estimate. Then hold the glider over your head. If it's easy to do, then you maybe need to step back just a few feet. Firm is what you're looking to feel.
Point the nose up at about a 45degree angle. Now, hold it a second and look at that beautiful airplane.  Why? Because you want to look closely at the ON/OFF switch you dummy. It's dead easy to launch gliders with the RX turned off. OK? Now, About the 45degrees..... it usually won't be enough for your best launches, but right now you don't want to launch her into an instant stall. And point her too straight up and that could happen.
Now pull her back a bit so you can "throw" and "throw". If you've trimmed her on your trimming throws so she always sails without porpoising and goes a long way, she'll almost instantly turn that 45degrees into whatever is perfect for her. By the time you've got your throwing hand to the TX she will have started to CLIMB LIKE A.... A..... jeez..... A GLIDER ON A HIGHSTART (there ain't nothing else that climbs like that... so.....)
You may have to steer left or right. Try to leave the elevator alone on the first launches. Be easy, because she's going way faster than trim speed. What a glider does is convert it's weight into speed. With the highstart pulling on the towhook, a glider thinks it's suddenly gotten LOTS heavier. That all it thinks. But it then flies as fast as it would if it was 3 or 4 or 5 times heavier. And it's "heaviness" isn't coming from straight down, it's coming from the pin that's holding the highstart into the ground. So the glider will "trim" itself as if the pin was straight down. And fly a very fast arc whose center is that pin.
Watch the line and when the glider has gotten through about 70% of that arc try to judge if she's started to slow down somewhat. If she has then pull UP. If she hasn't, then I bet she's made it to 70% while you were trying to figure out if she's slowing down..... grin.... so pull some UP.
With luck, you will hear a ping and a POP. And she will probably start into a climb and stall unless you let go of that UP. And by golly..... you and she are on your way...... dang if I ain't got a tear in my eye...... remembering.....
The ping will be the parachute ring coming off the towhook. The POP will be the chute being pulled open suddenly by the remaining tension in the bungee. There aren't any sounds more beautiful than those. Good thing, because with thermal soaring, we really spend way more time listening to those two sounds than we do soaring. As soon as you hear the ping, get off the UP stick.
Hey, I wish you luck and wish I still lived near a decent thermal site. I haven't heard that ping-pop in way too long and am much the poorer for it. You are a very rich person.
BTW, I guarantee my advice. The guarantee: "If you're not entirely satisfied, there will be no additional charge."
< Message edited by darock -- 7/6/2006 4:19:25 PM >
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A few questions on my first sailplane - 
