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Old 08-09-2013, 02:03 AM
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Hossfly
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Default Good to see a Free Flight Forum:

Anyone care to describe how you fix the wing for the Javelin (???) Launch for Outdoor Hand Launch Glider?

Sure would like to try that for sport HLG flying. Too old for contest stuff. HA
Old 08-10-2013, 04:37 AM
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collector1231
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Old 08-13-2013, 08:14 AM
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BMatthews
 
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Collector, I think he wants to use the classic over the shoulder javelin launch style instead of side arm tip launching.

Hossfly, a lot of us older guys with shoulders that are becoming increasingly less tolerant to that sort of nonsense are switching over to catapult launching. It uses a single 9 inch length loop of 1/4 flat rubber such as used for rubber flying to launch our gliders up with the same to 50% more than what our arms could manage even when we were in our primes. The only difference from the classic hand launch is to add a short "stinger" at the tail which has sandpaper glued around it for grip and to add a small hook at the wing's leading edge for the rubber to hang on. You then still set the model with the correct bank and nose angle before releasing. The gliders go up with the same pattern as the classic style hand launch toss.... just higher in most of our cases....
Old 08-13-2013, 08:17 AM
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I'm not sure what you meant by "fixing" the wing. Of course a good, well made glue joint is essential. But I'm guessing you meant how to trim the model to pattern up and transition neatly to the glide. Assuming this is what you are after here's a little article I did a while back for just such folks as you that are getting started;

Building and Trimming Free Flight Hand and Catapult Launched Gliders.
The flight trimming for hand launch FF gliders starts on the building board.

If you're right handed you want the model to circle to the left in the glide. To achieve that with only adjustments to the fin means that there will be much too much turn in the launch. To get around this it's normal to use some stabilizer tilt to provide some left turn. This means you want the left side stab tip to be about 1/4 inch high compared to the center line. Reverse everything if you're left handed and will be going for right hand circles.

To aid in smoother recoveries from stalls you want a little bit of washin on the left hand wing tip. I used to warp some into the wood but now I "toe in" the outer dihedral break on the left side by 3/32 inch over a 4 inch chord. Tapered wings with smaller chords at the tip break would be angled appropriately less. I know this sounds odd since the washin at the tip is fighting the rudder. But trust me. Having the model set up so the turn fights the washin is what aids in avoiding those frustrating never ending series of stalls that never seem to damp out. Models set up with a touch of washout will settle back down a lot nicer and with a more rearward CG than "straight" models. If the wings are simple V dihedral then make the center line joint skew to the right at the leading edge by 1/16 inch over 4 inches of chord, or some scaled down amount for smaller chords, so you can glue the wing on straight across but still have a touch of washin on the left side and a touch of washout on the right.

Now to the flying field.

To avoid the looping over and hitting your self in the back of the head or having it gyrate around uselessly and stalling a few times before settling into a glide you need to trim the model to find the most rearward CG location that will still give you just a little bit of pitch stability. I know it seems odd but the best way to avoid these typical problems is to trim the model so that it is LESS strongly pitch stable. To fly their best and trim out the most easily it's pretty common that free flight models need to be set up with their balance point really far back and on the edge of being almost but not quite being unstable. Models set up this way handle the dynamics of the powered or climb portions of their flight with more control, a smoother overall climb pattern, gain more altitude and have a smoother transition to the glide..

To test this you're going to do two types of test gliding. The first is to adjust the stab warps by breathing on the balsa and curling it slightly to achieve a nice slow and floaty glide with no signs of any stalling. The second is a "pitch stability" test toss where you push it slightly faster and slightly down towards a point about 25 to 30 feet ahead. This faster test glide should show a mild but still noticable pitch up to a mild stall. Don't worry that it won't recover to a glide from such a test glide. You're just looking to be sure that it's still stable. Keep moving the CG back a bit at a time and retrim for a nice stable glide then do the stability test. When it won't raise the nose up to a mild stall before it hits the ground when aimed about 25 feet away you know you went too far. So move the balance back forward to the last test point and retrim the stab warping to get a nice slow and stable glide. You should also be looking for signs that the model is turning to the left during this test gliding. It won't turn much but you should see definite signs of it beginning to come around to the left. Add some left fin warp to where you're seeing that it's beginning to set up for such a turn.

Now it's time for the launching tests. Start with a fairly shallow angle and half power throws or catapult releases. For these you'll want more of an over the shoulder toss or a level wings release since it's not going to go far enough "under power" to really arc around. So more of a level wings and nose up at around 30 degrees is suitable. What you're looking for during this is that the rudder isn't so effective that it's over rolling the nose and making the model roll too far in the climb. Ideally you want the model to roll and turn in the climb about a third to quarter turn and be left hanging with the left wing low and almost no airspeed. The glider should then roll down into the glide and continue away. Play with the fin warping until you get this. In the longer glide that comes from this higher launch watch for signs of stalling or for the turn to get too tight and want to spiral in with a "death spiral". The glide turn should be roughly 30 to 50 feet in size. I like to aim for around 30 to 40 myself but remember that you're playing off the stab tilt and fin where the fin adjustment is used for the climb. And the climb takes priority in the fin adjustments.

If you're getting promising results from the low power testing then it's time to wind up more. You'll need to play with just where you and the model want to hold your arm by altering where the throw occurs between the "over the shoulder" and "sidearm" throwing. For a catapult model you're looking at full on side arm pull to stretch the rubber the most and you want to angle and bank the model to around 45 degrees up and roughly 45 degrees bank. Alter this as needed to where the model runs out of inertia up top with the correct attitude for the transition. Models with a strong rolling action in the climb can be thrown or released banked strongly to the "sidearm" position. Others with less rolling action in the climb will need something up more towards "over the shoulder". Some minor tweaking of the fin can add to or take away some of the rolling/turning in the climb. A little goes a LONG way so go easy.

When it's all working well you'll see the model arc up in an S curve to the right then roll over to the left. The model will end up somewhere overhead and over to the left havng performed somewhere around a 120 to 200 degree turn during the climb. Ideally it'll end up slightly nose high and strongly banked with left wing low. As the speed bleeds off it should transition smoothly into the glide with little or no stalling by rolling down into the low wing and leveling up and just go into a nice glide circle.

From there if you did your job right and found it some bouyant air the model will begin circling upwards. When you get a little better at picking the air you'll understand why so many folks are adding DT systems to chuck gliders.
Old 08-28-2013, 07:49 AM
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Hossfly
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What I want is info on how to perform the Glider Launch that some RC fliers use. One holds the wing at a spot on a wing tip, (I think the left tip is used) and does a twril to sling the glider into the air, I was informed several years ago that this concept is now used in FF HLGliders, and has become the best method to launch a HLG that is not RC.

There has to be some way to hold or place something on that wing tip to hold things together.

I know how to launch OHLGs from the old school. I can still get a Sweepette up fairly high but the sling-by-the-wing (my term) is much better.

Last edited by Hossfly; 08-28-2013 at 07:50 AM. Reason: misspell

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