High Start Question?

[RCFlybry]

Hi all,
I have been flying for about 11 years now mostly glow until the last two years and that's been all electric.
I would really like to ditch the electric glider scene and move up to a "Pure Sailplane". After catching my first thermal a few months back I've really become addicted to flying my sailplane and would enjoy it even more by catching thermals without the aid of a motor. I mostly fly my sailplane by myself as my other flying friends just aren't interested in them. "Too damn much work to find lift". They say.
I have never seen anyone launch from a high start and wondered just how high can you get off of a good launch? Also are there some that are better than others. I'm sure that some of it really depends on the size and wingloading of your plane. I was thinking of something around the size of a gentle lady for my first Pure Sailplane. Although that Bird of Time really strikes my fancy as well!

Bryan

[Gliderguy]

Hollyday used to sell the good high starts, now www.aerofoam.com has them. You might also want to look at www.skybench.com for their tubing and other products and information (also lots of good stuff). The Bird of Time is a beautiful ship but I have heard it is quite a pain to build. You might consider one of Skybenches Bird series. I have a Lil Bird 2 meter that I really love (except I broke the stabilizer chasing my cat out of the attic yesterday :mad: ).
I also have a Oly ll that I like even better probably cause it's bigger. The Oly ll might be the one you want to try for pure soaring pleasure and it is a fairly easy build and fairly cheap as well. It's the one that everyone wants to hang on to just because it's so nice to fly. Good luck with whatever you decide.

Oh, and welcome to the pure stuff (flying that is):D

Gliderguy

[onlyfingers]

I bought my hi start and a MAD Highlander (2 meter, EPP foam) from Northeast Sailplane Products. http://www.nesail.com/pinnacle.html I built the plane over the winter. This summer is my first as a sailplaner. I had help/advice learning how to build the plane and use the highstart.

I have to travel a bit to the club field, so I use my own highstart on a local field. You've got to have a big field. The Pinnacle M I have has 100 feet of tubing, and 300 feet or so of braided line. To launch, you stretch it out another 300 feet. Our soccer field is almost big enough on a diagonal. If the wind isn't right, I stretch almst the whole 300 feet through shoulder-high weeds that are growing where corn was last year. (If there was corn there this year, I would not be able to fly when the wind is from the south.) With an electric, I don't think you need as much space to launch.

The field is mowed for soccer, so the tubing and line keep clear of the weeds, for the most part. If the surface of your field is too rough, you may pierce the tubing. That hasn't happened to me, yet. (Once I tried staking the highstart 20' or so into the field where the corn was last year. But the tubing was being pinched by the 8" stubs of corn stalks, so I quit that.)

I have an electric, but decided to learn on the Higlander cause it bounces better. Next summer, I will probably fly the electric, too, for days when the wind isn't right for highstart launches. (I'll need it if they plant corn next year, since I won't be able to walk 100 paces through someone's corn field...) (If they had planted corn this year, I was going to shorten the line on the high start, from 300' to 200'. I'm glad I didn't have to do that.)

So, finally, your question--how high? If you launch into a little head wind, the glider wind will "kite" the glider so that it has a big component of up, not pulling as much forward to where the high start is staked. I figure I am up pretty much at the length of the line plus the un-streteched tubing, which is 400 feet.

On still days, without the wind keep tension on the tubing, lauches are not as high--maybe 250 or 300 feet.

[Chipwillis]

One thing Id like to add is when doing your first high start launches.... for the first couple launches try neutral trim. Fly your plane and play with the trim, and find the middle ground between slow/just above stall, and nose down, flying fast. Try and get close to the middle of that.

This will help ensure a uneventful launch, where the planes attitude is not too steep causing a possible pop off or stall, and not too flat. Flat launches are less stressful, just as long as you are smooth on the elevator. Pulling up at a greater speed will get a quick pop off.... but its not the low just let go of the airplane pop off.... those suck!

After time, you will begin to see the realationship between tow hook position, how trim affects the launch, and wind.

hope those things may help. It is actually very easy, and the sight of a glider goin up on tow is awesome today as it was years ago for me.

Chip

[ICTHRMLS]

Also don't forget that one size high-start does not fit all. It is perfectly acceptable to change the length of the rubber and line to suit your field boundries. We have flow with mini high-starts using 15-20 feet of rubber and 30-50 feet of line. While this surely won't get you 400 feet launches it is great for small fields and LANDING practice. Plus if you do snag a low level thermal the accomplishement is that much sweeter. I recommend taking your field length and reducing it by 50-100 feet (for pop-offs) then split the remaining distance into a 3 to 1 ratio of line to rubber. You could even use snap swivels (125 lb ball bearing type) and make several types out of the same high-start - just hook up what you need for different fields or tasks. My nickels worth anyway.... :D

[Fast-Forward]

I bought some surgical tubing ($13.50) from my Honey, she works at a medical supply company. I used a 16" FG rod (free) from an old dome tent (they usually have about 8-10 sections complete), wrapped the tubing around the FG rod then taped with hockey tape ($2). I connected the tube to 45lb pink ice fishing string ($4) (about 50-85ft) via a clevis pin ($2.50) and some radiator clamps ($2) (cover clamp and clevis pin with hockey tape also, it avoids broken line). I used a key ring and some nylon fabric attached to the key ring for visibility. Time and money was 30 minutes and $23. If you were at the NEAT fair you would have seen it. It launches to about 200' and is ample enough to get thermals in the right conditions. I caught a Thermal Friday at the NEAT Fair from 50' and rode it to 1000'. Sweet!