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Author Topic: catapult weight  (Read 1570 times)
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sleepy gomez
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« on: June 16, 2016, 08:06:35 PM »

What is an acceptable weight for a catapult glider 15.5 flat span, 54 sq in area? I seem to be having trouble with weight (mine too,I have tried eating 4 lb balsa but it hasn't helped)? SLEEPY
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danberry
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« Reply #1 on: June 18, 2016, 12:25:17 AM »

I'll say 18-20 grams.
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FLYACE1946
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« Reply #2 on: June 18, 2016, 05:02:33 PM »

Sleepy you can trust his answer. Dan knows his stuff.
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danberry
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« Reply #3 on: June 18, 2016, 09:43:18 PM »

Well, it'll thermal just fine at 28 gms..........
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Tmat
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« Reply #4 on: June 23, 2016, 02:28:53 PM »

My 16" catapult with DT weigh 18-20 grams. They fly fine at 20-22 grams and glide a bit better in calm air when they weigh 16 grams but it's a challenge to make them that weight.

Tmat
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F1B guy...
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PeeTee
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« Reply #5 on: June 23, 2016, 02:53:16 PM »

Tmat

What a pleasure to hear from you again, you and the Leeper have been missed by the duration aficionados - especially by the Wetherspoons' lunchtime club Grin

I've just weighed my latest (18 months in the making Roll Eyes) catty and it's a porky 25g. However it seems to climb and glide quite well, especially when launched into a bit of decent air. All I need to do now is practice.

Peter
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FF Bruce
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« Reply #6 on: June 23, 2016, 09:20:57 PM »

I use a spruce body and a silly putty timer and my heavy 15" Cat. is 11.5 grams.I have hundreds of flights on it.Total cost for the model about $5. 
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Dimeflyer
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« Reply #7 on: June 28, 2016, 07:41:27 PM »

I second your trust in Dan's advise !
George
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stuntguy13
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« Reply #8 on: January 15, 2018, 07:57:34 PM »

Hi guys, I'm kinda new to this board, been flying over 55 years. Mostly fly OTS in contests but one of the guys that I fly with started talking about these catapult 12" class gliders that they flew at KOI down here in FL not to long ago. As a kid the first contest I entered was a HLG. I told my dad I was flying HLG in the contest (actually it was an excuse to go). I had some fairly good gliders and after going around all the other events wandered over to the HLG area, found a timer and put in my official flights. It was overcast and windy but to my surprise I place 1st in senior.

Anyway, once my friend started talking about these catapult job I got really interested and we decided to build a few and have a go. This is great fun and lots of room to innovate. Which brings me to the question for this thread. Has anyone used weight added at the CG to trim for wind conditions?

Best,    Dennis T
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lincoln
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« Reply #9 on: January 16, 2018, 02:45:15 AM »

Are you guys talking about the kind of catapult gliders that are launched by a 9 inch loop of 1/4 inch rubber? If so, those weights sound a bit heavy. Then again, I used to build mine at 12 to 14 inch span and skip the DT. I don't remember just what they weighed, but I'm sure it was under 10 grams.  I found that the DT took just as long as the rest of the model to build and to get working right. If memory serves, I've lost two DT catapult gliders and not more than 4 non-DT catapult gliders. In one case, the aluminum tab DT, which I'd built according to someone or other's drawing, failed and snapped off in a thermal. Bye bye model. The other one, which was pretty heavy, vanished in some long grass and bushes, well within the field boundaries, even though I knew about where it was. In the case of one of the non-DT losses, I knew where it was, but I'd had 3 good flights and I was tired of wading hip deep through water with thin ice on top of it, sans waders, every time I had a good flight. Another one vanished up and away, and I'm sure I lost at least one other that way.

All the DT setups I've seen look awfully draggy.
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