Flying / Tuning

Bill Grenoble Denny Maize Joel FonerPublished on October 30, 1998

Flying Your Terminator

The Terminator is designed to be able to fly faster than the “floater” ships, so you may learn a bit while getting used to it. If you started out with an Olympic, Paragon or similar “floater” ship, here are some thoughts to keep in mind.

“Floater” sailplanes have very narrow speed ranges - typically their fastest workable speed is only slightly above their stall speed, and the optimum thermalling speed is not far from their slowest workable flying speed.

The Terminator has different flying characteristics, and once you learn them, it will reward you with much more flexibility in chasing and hanging onto lift. The Terminator wing has a fairly wide speed range, but unlike the “floaters” a Terminator does best at a speed noticeably higher than its stall speed.

To experiment with this, try a few launches from one end of the field, facing into the wind. For each flight, fly straight out, no turns, until and if you have to turn around at the other end of the field. We’re not trying to find lift for a couple flights, just checking out flight behavior at different speeds, so don’t worry about where the thermals are for now. For the first few launches, try flying ‘slow’ - at the speed that feels just above stall.

Then do a few launches with progressively more down trim (add one click down for each throw). Let the Terminator come up to speed and get “on step” - resist the urge to pull up and slow it down right away. You’ll find that if you let it hit cruise speed, you’ll get noticeably longer flights and longer durations.

(Note that playing with leading edge or trailing edge shims, and moving the center of gravity around, will change the cruise speed and behavior by quite a bit - try some variations and find the one that “flies right” to you.)

Now you have a sense of the “natural” cruise speed for the ship, try to cement this in mind, and fly at this speed while trying for lift. In addition, remember that if you round the top of your throw on the late side, the Terminator will fly at slower speeds, but to get the most out of your throw try to round the top at cruise speed. This way you don’t have to give away height just to get the speed up to where it should be. Do not be scared to pull elevator in turns - with enough elevator the Terminator will turn tight at high speeds - do not start off with the assumption that you must slow down to turn tight!

Now try several flights with a second goal in mind (again ignoring thermals - if you can!). For each of these flights, try pulling into a turn just after launch, pulling a tighter turn on each throw. Keep turning until you have to level out to land. Keep trying tighter turns until you hit “the edge” of how tight the ship will turn. Depending on conditions, you may find that you can turn high performance circles of well under 12’ in diameter (some people have reported a useful turn diameter of as small as 8’!).

Unlike ships with higher speed airfoils, the Terminator can turn very tight circles at higher speeds, so it’s worthwhile to learn to fly the Terminator faster than your initial reflexes will tell you is ‘right’. Flying faster will give you a few quite useful benefits:

  • If you don’t happen to launch into lift, and you fly at the Terminator’s cruise speed (instead of just above stall), you will be able to search around the field much longer than other HLG’s to find where the ‘real’ lift is.
  • You will be flying further away from your ship’s stall speed, so you will be able to fly on windier days with confidence, since gusts will affect the ship less.
  • You will have much better control in thermal turns, since at higher speeds the control surfaces will have plenty of control authority and very little “mush”

Tuning Your Terminator

Here are some things to try while tuning your Terminator:

  • Try adding a trailing edge shim, 1/16" at a time. Each shim will speed up the cruise, and often one shim (or so) ends up with the right decalage for this fuselage and tail design. Then try removing the trailing edge shims and add a leading edge shim. Adding LE shims will slow the glide down, but you may find that the Terminator starts to stall too easily, will start to “balloon” too much, or won’t penetrate well if you go too far. If you find that your neutral cruise elevator surface setting is not “dead-level” with the v-tail or elevator you probably need to adjust the wing angle (neutral with elevators “up” slightly - shim the TE, elevators “down” at neutral trim means you should shim the LE). Small changes in angle may not change the elevator setting much, so feel free to play around even if the elevators trim level at cruise - you may like the results!
  • Try playing with the center of gravity. Although the Terminator will fly well through a broad CG range, you may find that somewhere from 2.75" - 3" from the leading edge will give you the best tradeoff between stability and good manners. Although it will fly with a farther rearward CG, some have found that farther rearward balance points may trigger occasional “tucks” under high speed launch conditions (although it does make the plane very sensitive to lift). This will have to be a choice based on your personal preference and flying style.
  • If the Terminator seems to balloon a bit when entering a turn, but only while you are holding rudder, then you need more down and less up travel in the ruddervators. If it seems to sink too much in a turn, then you need more up and less down travel. This is pretty personal - some folks like to purposefully “detune” the tails so that turns need very little up until you are fairly well into the turn, while others like to have the response timing feel like a conventional tail ship. Play around until you think it feels natural, and then go fly!