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  #61  
Old 09-04-2007, 12:53 PM
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dwmzmm dwmzmm is offline
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Quote:
Originally Posted by Shreadvector
I replaced the elastic on the Groundhog 16 built by our club President Martin Bowitz at one of our classes about 10 years ago and I loaded a B4-2 motor and launched it last Saturday.

Insanely perfect flight with only a slight stall (I prefer a slight stall to a sprial dive....). It circled for quite a while, but I did not time it. Landed within 50 feet of the pad.


I've been wanting to build several Groundhogs myself, but want to use a burn through the
string method of releasing the wings from their swept back position. I'm having a tough time trying to figure out how to rig the string(s) to make this work.

Perhaps someone here (or maybe Jon Robbins himself) can hop on board this message
thread and spill the "secrets" on how this can be done. I'd like to start on building a small
fleet of Groundhogs for use in NAR competition this year. Here in the Houston area, we
already have four Regional meets in the works for this contest year.....
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  #62  
Old 09-04-2007, 01:04 PM
Initiator001 Initiator001 is offline
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Quote:
Originally Posted by Shreadvector
I replaced the elastic on the Groundhog 16 built by our club President Martin Bowitz at one of our classes about 10 years ago and I loaded a B4-2 motor and launched it last Saturday.

Insanely perfect flight with only a slight stall (I prefer a slight stall to a sprial dive....). It circled for quite a while, but I did not time it. Landed within 50 feet of the pad.


Fred,

Here's a picture of the Groundhog I took at the launch.

Bob
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  #63  
Old 09-04-2007, 01:11 PM
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Shreadvector Shreadvector is offline
Launching since 1970.
 
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Location: Southern California
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Quote:
Originally Posted by dwmzmm
I've been wanting to build several Groundhogs myself, but want to use a burn through the
string method of releasing the wings from their swept back position. I'm having a tough time trying to figure out how to rig the string(s) to make this work.

Perhaps someone here (or maybe Jon Robbins himself) can hop on board this message
thread and spill the "secrets" on how this can be done. I'd like to start on building a small
fleet of Groundhogs for use in NAR competition this year. Here in the Houston area, we
already have four Regional meets in the works for this contest year.....



I have my 1984 hand scribbled instructions in front of me. If I can scan them I will post them. Basically, insert & epoxy a staple or small metal loop into each wingtip bottom, and to the fuselage below the motor pod. Tie the cotton thread to one wingtip, thread it through the other and then run it forward through the fuselage loop/staple. When ready to fly, install a motor and stretch the elastic into place. Then run it up through the vent hole in front otf the motor and tie or tape it in place. Test several times on the ground to ensure safe and relaible operation. Testing is done with a sharp X-Acto knife or a "punk" or incense stick.
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  #64  
Old 09-04-2007, 02:47 PM
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Shreadvector Shreadvector is offline
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Location: Southern California
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Bingo.
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  #65  
Old 09-04-2007, 05:50 PM
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dwmzmm dwmzmm is offline
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Quote:
Originally Posted by Shreadvector
Bingo.


Thanks, Shreadvector! Got it bookmarked! I really didn't want to build one with the piston/
wire format as I was afraid that, after a number of flights, the buildup of the residue from
the ejection charge would affect the piston's operation. This is true as I usually keep flying
the same boost & rocket gliders I have in my fleet over and over again so long as they
continue to perform (such as my CMR Manta, Buzzard, upscale Buzzard, Orbitron, etc). Some of those vintage models just named, built in the 1970's, are still being flown (by me)
today in NAR Sanctioned competition (and I still win with them!!)....
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