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Author Topic: Is It Really This Hard?  (Read 1936 times)
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Falco
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« on: September 23, 2013, 09:04:14 PM »

Growing up I made several free-flight hand-launched gliders. After noticing most of the competitions for FFHLG's occur in the plain states (Midwest) I came to the conclusion that it would be next to impossible to catch thermals strong enough to support my gliders here in Pennsylvania. I just couldn't get them high enough to reach effective lift. This past winter I was wasting time online (easy to do) when I thought I'd look up videos of FFHLG's on Youtube. Personally, due to the prevalence of video games I wondered if kids did this kind of thing any more. I wanted to see what someone with a strong arm could do. When I stumbled onto videos of free flight discuss-launched gliders I was amazed at the height these people were getting and the significantly larger wingspan they were using. I thought, “What the heck, I'll give it a go.” I eventually got a Sting 30 from A2Z Corp. I say eventually because it took a good 4 months for a kit to become available. I don't know if there was slump in the availability of balsa but I finally got the kit in August and assembled it. Followed all instructions, got a good test glide and right turn with the rudder. Made sure the center of gravity was perfect (45% back from leading edge if you must know); made sure the angle of incidence was spot on.

Drove to 'my' field (beautifully huge, fairly level, and with cut grass) did a couple of test glides and went onto the 'real' launching. Over the course of one week I visited the field four times and got maybe three passable flights out of twelve actual launches. Yes, I crashed that much. Several repairs were made. The glider would ALMOST NEVER recover on a launch – I'd launch it level and towards the left (I'm right handed), it went up to a crescendo, stall, steep decent, barely start to pull up, and SMASH into ground. This happened no matter how much I increased the incidence on the stabilizer (the dethermalizer is of the tail boom variety and there's an incidence screw in the aft section of the fuselage about where the tail boom is hinged).

All launches were of medium strength in order to control launch angle and the fact that I have no earthly idea how to successfully discus launch.

IF I did get a successful launch-to-glide transition it was not a very high launch and would go into a tight right turn, descending quickly and perhaps roll onto the right side and hit ground causing it to cart-wheel after impact. This is the worst kind of crash. I should note the airspeed after recovery on these launches was very fast (too fast for a gentle glide).



Needless to say I now have questions and this is the ONLY place I can find that actually addresses the very specific FF TLG niche.

1. Is there a preference for hand grip? I have the sand paper type but they also included a peg for that style as well. Are there any advantages/disadvantages to each?

2. Are there any “beginner” TLG kits out there? I say beginner because discus launching is so foreign to me it's like walking on Mars. I had no problem with the traditional overhand launches of the FFHLG's, but I just cannot fathom how the discus style is supposed to work. Yes, I've read Rewinged's “TLG Beginner's Launch Guidance” thread. I think you could easily fill a chapter concerning the proper technique and then several chapters diagnosing different flaws in technique and their resultant crashes. By beginner's kit I mean something that's built almost like a tank. Yes, I know we're building gliders here but I seriously need a tank to learn/get through my mistakes on before I can attempt anything not remotely “triple reinforced”.

3. Is there any way to create a “test-bed” glider with which to experiment and not really care about breakage and crashes? This is probably pie-in-the-sky thinking but if there was a material that let me cheaply and quickly put together different wing/tail configurations, make massive adjustments (just to see what happens) I'd be thrilled.

4. Speaking of test-beds, what's the latest technology/materials being used for FFHLG's? I saw someone had a beautiful Sweepette with a digital timer in the nose and have heard rumblings of wings that unfold after launch. Always interesting to see what's new.



Well, Fall is swiftly approaching here in southwestern PA and I have “killed” my glider with too many wrecks. The last one sheared the wing clean off and split the fuselage from front to back, so no more repairs can rectify it. Oddly enough the wing and tail boom (includes stab and rudder) are perfectly fine – these were the things I thought would break first. I'm not going to be taking my bandaged and now greatly overweight glider to the field any more but I'll see what help there is available in the way of responses and kits/materials. The videos I've found are inspiring but alas, there are just so many variables when launching discus. It's a shame because there is great potential with TLGs.

Sorry for the tome but I've had a rough time of it and am appreciative of 'kindred spirits'.
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Rewinged
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« Reply #1 on: September 23, 2013, 10:21:33 PM »

Since you read my beginner's guide, you already know that I crashed my glider twice the first day out, with the second crash putting it in multiple pieces.  So, there is a learning curve.  But no, it is not that hard.

Oops...just got called to dinner.  More in a bit.  In the meantime, look at Stan Buddenbohm's smaller gliders.  You can see Stan's stuff at http://www.discuskid.com/Pages/BUddenbohmProducts.aspx

Stan's stuff is the very best, and his smaller gliders should be easier to learn with.  The best approach, of course, is to find a mentor to watch you.  Absent that, somebody to video your launches.

More after dinner...

--Bill
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« Reply #2 on: September 23, 2013, 11:07:17 PM »

From your description of your crashes, I would guess you have too much rudder offset, and/or perhaps too much skew. 

I would go back to the test glides.  Start with the CG as per plan, the skew per the plan, and no rudder offset.  Adjust the incidence screw until you have a nice flat glide, based on easy tosses at glide speed.

Next, throw (overhead javelin style) slightly harder and slightly upward with a right bank.  This should get you sufficient altitude to more clearly observe the glide behavior.  Make sure the glide circle is not too tight.  Somebody will chime in with more accurate info, but I would guess my glide circle (34-inch span glider) to be at least 150-foot diameter.

If that goes OK, do the same thing, but a bit harder.  Again confirm the glide angle, glider speed, and turn diameter.  Add a tiny bit of rudder if your glide turn is too wide.

If your glide turn is too tight before adding rudder, you'll need to reduce skew.

Don't proceed to tip launches until everything else is really good.  Then, before tip launching, you could add 1 turn of the incidence screw for safety, making sure you are increasing incidence!  (I still have to think about what is happening when I turn the screw, because it is different for my CLGs and TLGs).  Just remember how much incidence you added so you can take it back out when you need, and fine tune from there.

Finally, as per my beginner's guidance, when you throw it by the tip, make sure you keep your elbow straight, and attempt to throw the glider without any bank, and throwing it upward only about 15 degrees.

Some issues can come about from a lack of power.  Make sure you use your whole body, by coiling up before the throw.  After they have success without any spin, I have people do a 1-step, 180-degree spin next.

I hope you can find some success!  TLG is really a lot of fun.
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Geneulm
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« Reply #3 on: September 24, 2013, 10:27:21 AM »

If built per plan, you are just a few adjustments away from having a great flying glider.  Attend the Eastern States Free Flight Championships in Waywayanda, NY October 19-20.  If you are in PA, it isn't that far.  And we will get that glider flying!  See  http://www.freeflight.org/competition/Calendar.htm

Gene
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-John-
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« Reply #4 on: September 25, 2013, 10:52:57 PM »

Falco,
personally I like Stan B's Dynomite as a starter glider. It is fairly easy to throw, even with one step launch. Try to build it true and correct, as warps can give you fits on most any glider. Bill and Gene have said the rest. And don't give up, TLG's are awesome!
If you purchase any of Stan's kits, buy a copy of the Generic Tip Launch Glider Instructions also. Those are important for a proper build.

-John
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NormF
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« Reply #5 on: September 25, 2013, 11:19:25 PM »

Bill and John have rec'd Stan's gliders and I totally agree. In the latest catalog (use Bills link) there are two new beginners TLGs, Easy18 and Easy24. A good place to start. You can order just the plans, but I rec you get at least one kit. The kit will give you an idea of the proper wood selection.

NormF
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oian
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« Reply #6 on: September 26, 2013, 10:07:27 PM »

My first venture into tip launched gliders, due to a very fortunate event, was very successful. I was going to buy one of Stan's kits from him at Lost Hills, but he didn't have any with him, He did however offer to sell me one of his built and trimmed models for a little more than the price of a kit. I was very nervous about the first flight so I took it to a very soft and deep alfalfa field and quickly discovered that no matter how I threw it (Once I put some effort into the launch) the plane would always recover. Too Much to the left (I throw right handed) and it would merely make a circle without much altitude gain and recover, too much to the right and it would climb stall a little and recover. I haven't built another, but I suspect that if it's built as per the plan it will probably be close to flying trim. I've built a couple of Stan's catapult gliders and both flew safely from the get go with the adjustments as per the plans. His models are well thought out and seem to be very easy to trim. By the way, with a new model, I still try to find a ready to cut alfalfa field for the first couple of flights. It's even better than the proverbial tall grass.

John
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skootertrash74
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« Reply #7 on: November 22, 2013, 11:26:54 PM »

Falco, the reason you had a difficult time getting your kit is because a2z does an amazing job matching wood to the design(they should, $75 per kit).. and I depleted thier inventory of this kit a couple of years ago... I bought 4 in a matter of 3-4 months... lost all of them but one to thermals... the timers suck.... but the design is world class.... finicky as hell, but world class. The one I didn't loose to a thermal was stomped and lit on fire after a week of agrivation...
 I obviously made a mistake during assembly....
Due to recent events, I will no longer spend a penny with a2z, but I did save a copy of the plans on the sting30. Stan B. is the man... but this design in the right builder/competitors hands is lethal with very little input...
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Hepcat
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« Reply #8 on: November 23, 2013, 04:58:43 PM »

My first thought was: too much right turn.  But then my TLG experience is limited to a few days before arthritis deemed that that was enough.

However, one thing that I wonder about, in reports on how a model is trimmed or suggestions of how it should be trimmed, is how often there are remarks like turn the screw to increase the incidence or I packed under the tailplane to increase the incidence. This leaves one wondering just what did happen to the wing and tail incidences.  How much more clear it would be if people said I changed this and that to increase (or reduce) the longitudinal dihedral (or decalage).

Sorry for the inelegant wording!

John   
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Falco
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« Reply #9 on: August 24, 2014, 01:03:18 AM »

Well folks, since the debacle with A2Z Corp's Sting 30 (nice kit with horrible instructions) I've since bought and built Stan Buddenbohm's Easy 24 due to the promise of it being good for beginners. And I got a couple good days at the field with it! Nothing to write home about but any day you launch something and it doesn't shatter is a good day for me. Alas, I did shatter it on two different occasions but the same thing happened in that I rolled the plane too far to the left and it “cartwheeled” into the ground shattering the fuselage. Again, I did have some good flights. So, I come with some questions and general observations.



Oh dear God does discuss launching have 10 – 12 things going on at once! Remember the old days when you'd just whale a glider over-hand like you were throwing someone out from left field? So much simpler, 10x more controllable. Now I feel like I'm a fricken' drunk ballerina! Good grief! There's the upward angle, the left tilt angle, the perfectly timed release, the follow through, the torquing of the back, the planting you're right foot, rotating the shoulder, rotating the wrist. . . Seriously, whoever came up with this must have stumbled onto it accidentally (no doubt at the end of the frustrating day at the field) or someone just adapted it from the guys with radios. Really, a great concept as we'd never build anything larger than 24” with the old style launch. But c'mon, I have no idea how to control anything whatsoever, hence two shattered birds.

My best launches resulted from a rather horizontal flight path where a lot of energy is spent arcing to the left (I'm right-handed), almost parallel to the ground. In videos I've watched almost everyone has a very vertical launch. Not sure how to achieve this – might have something to do with incidence though. Unless I have a horizontal launch (which means wasted energy) my glider stalls at the top of the launch.  It then loses 20-30' of altitude. Heck, it may not recover before hitting the ground. It also stalls with the slightest headwind. Is there something I can do about this? Does it have anything to do with incidence? Yes, I have the CG correctly tuned and have trimmed the glide properly.

Does having a peg grip aid in getting a more consistent launch? Both gliders I've built have sand paper grips and it's hard to get a good consistent launch (as evidenced by my now “retired” Easy 24),  The sand paper grip almost seems to beg for a slightly different launch every time.

I know we're not building tanks here but there must be some better material for the front half of the fuselage. It seems to be the weakest link on both gliders I've built. The Sting 30 had a thermalizer with carbon tail boom and shattered on second launch (did I mention the three different sets of contradictory instructions make it an awful kit?), the Easy 24 quickly snapped after a “cartwheeling” crash. There has got to be a better way of doing business here. I like nothing more than getting out to the field on a calm day and chasing a plane down but this sport is not very forgiving. Did I mention the discuss launch has a lot going on at once?



About Stan Buddenbohm's Easy 24':

Darn thing recovers almost every time! Good job Stan! Now the real question is what part of the design ensures this?

Not sure what purpose taping the wing to the fuselage serves. Certainly adds weight.

Thing is heavy! And it still stalls a good amount of the time.

Seriously, has anyone come up with pop-off wings and tail boom? Would probably advance the hobby wonderfully.



Oh, noticed A2Z Corp has since gotten out of the FFTLG market. Hmm, wonder why. . .

Thanks everyone for your responses. I don't get a chance to fly much so I rarely check the forum because, well it invariably depresses me as I'm champing at the bit to get out and fly but opportunities are limited. Basically when I do check in I binge-read. Great stuff and I wish I'd found Hip Pocket Aeronautics before I bought the first kit.
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« Reply #10 on: September 05, 2014, 10:22:39 PM »

Stan designed the Easy 24 to be easy to construct and low cost. The tape secured wing allows for ease of assembly and the possibility for incidence change by sanding the bottom of the saddle. It really doesn't require much(good) masking tape to hold the wing. Two wraps at each end should suffice.  I would personally think that one would not need sand paper grips on that small a glider, unless you throw really hard. Larger TLG's require some kind of Peg or grip due to the higher launch forces. One can use some 1/64" plywood on each side of the Easy 24 to reinforce the nose(since you need nose weight anyway).

I would say many of us out here in TLG land still have botched launches, so keep with it. Arm should be parallel to ground at release(no left bank), with maybe some nose up on the glider(Incidence should handle the rest). The trick is obviously timing; one shouldn't hold on too long. Too much over-thinking of the launch usually causes me trouble. You'll need to learn to do it as more of a natural movement -kind of like side arming a Frisbee. If you side arm a Frisbee enough times you get better at it. You don't have to do a full spin to have success in discus launching. Just take a few steps and throw it, but give it plenty of gusto so it gets out of your hand, begins climbing up, and gets some good altitude. As they say: "altitude is life".  
Take a close look at the V tail skew on your models, and follow Stan's instructions. Extra tail skew has caused me fits in past years. Getting the Incidence and CG right can be a challenge to, as too little incidence will cause lack of forgiveness on a goofy launch. Also, check the models for warps before you fly, and make every effort for a straight glider while you are building. Sometimes one has to build several models before getting a really good one. It is a learning curve.
Best of luck.
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Falco
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« Reply #11 on: September 06, 2014, 11:25:23 AM »

Thanks for the pointers. I take it too much incidence leads to stalling on launch?
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« Reply #12 on: September 12, 2014, 11:29:53 PM »

For sure you do need some incidence, or decalage. Nose weight can sometimes help with stalling, especially if the incidence is right.
What is the climb pattern of your model?

One of the best climb patterns I've had is with an old Dynamo Hum-2  36" span TLG. I launch it(fast) at about a 10 to 20 degree nose up angle with the wings level. The model begins a climbing arc to the left and rolls out at the top going in the opposite direction. Generally with a good solid launch(more around the body than up) the model doesn't stall at the top. If I try to launch the model up, I have much greater problems with stalling at the top. Not all TLGs that I own behave this way, some can tolerate a more vertical launch. 
Strong wind can really cause havoc with launches. It's probably a good idea to practice in calm conditions during the learning TLG stage.

Personally I liked the Dynomite as a learning platform. It is big enough to get out of your hand, and small enough to handle easily without a peg.
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« Reply #13 on: September 13, 2014, 10:55:46 PM »

I was flying my sweepette 30 at geneseo this week end.between Friday and Saturday I lost my launch technique.my glider was going in a wide shallow turn to the left, I realized that I was letting the outside(right) wing rise up into a steep bank. The cure was to press down with my fingers.I launch thumb on the bottom. I think I will move the upper sandpaper patch slightly inboard as a reminder.
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Falco
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« Reply #14 on: September 16, 2014, 10:29:19 AM »

Yeah, I've had some luck early on in the day and then "forget" what I was doing right and end up with a bad launch pattern. Unfortunately it's the best way to learn what's "right" and what's going to cause problems. Given all the wrecks and re-glued fuselages I've had I sure be an expert before long. . .

I recently purchased "How to build and fly catapult and tip launched gliders" from NFFS's website. Excellent resource as nobody mentions gluing the wing 1/64 to 1/32 to the right of centerline to prevent the hard lefts I was getting when launching. This is in addition to the stab being glued to left of centerline. Of course the section on trimming and launching was immensely helpful too. 
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