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Old Jun 16, 2008, 11:09 PM
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Noosa, Queensland. Australia
Joined Apr 2008
58 Posts
Question
Bungee choice - High Start Vs catapult

I am planning to buy a bungee for low wind days. I have been looking at the Hosemonster bungees. I will be initially launching a flying wing (Wowings Duck).
I am confused about the different applications and pros/cons of the highstart 100' bungee Vs a 25' catapult style bungee.
Any thoughts or experience would be greatly appreciated.
Steve
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Old Jun 16, 2008, 11:24 PM
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Quote:
Originally Posted by drcuzo
I am planning to buy a bungee for low wind days. I have been looking at the Hosemonster bungees. I will be initially launching a flying wing (Wowings Duck).
I am confused about the different applications and pros/cons of the highstart 100' bungee Vs a 25' catapult style bungee.
Any thoughts or experience would be greatly appreciated.
Steve

Sailplanes and/or any high aspect ratio (long wing) airplane HATE quick and violent launches. A 25' catapult is for a glass reinforced foam flying wings OR EDF foam jets, etc. Anything with short, stubby wings.

Highstarts, while sill lively; are the preferred way to build launch velocity and altitude on a sailplane without rapidly overstressing the airframe...Besides a winch of course.

-Sean
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Old Jun 17, 2008, 04:00 AM
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Noosa, Queensland. Australia
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Thanks Sean
That makes perfect sense to me.
Steve
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Old Jun 17, 2008, 12:18 PM
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Quote:
Originally Posted by FrogChief
Sailplanes and/or any high aspect ratio (long wing) airplane HATE quick and violent launches. A 25' catapult is for a glass reinforced foam flying wings OR EDF foam jets, etc. Anything with short, stubby wings.

Highstarts, while sill lively; are the preferred way to build launch velocity and altitude on a sailplane without rapidly overstressing the airframe...Besides a winch of course.

-Sean
High start worked well with the Rubber Duck plank. !/6 hp winch would make it vibrate like mad.
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Old Jun 17, 2008, 12:53 PM
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Quote:
Originally Posted by FrogChief
Sailplanes and/or any high aspect ratio (long wing) airplane HATE quick and violent launches. A 25' catapult is for a glass reinforced foam flying wings OR EDF foam jets, etc. Anything with short, stubby wings.

Highstarts, while sill lively; are the preferred way to build launch velocity and altitude on a sailplane without rapidly overstressing the airframe...Besides a winch of course.

-Sean

This is not quite correct. Any sailplane can be zip started (what you consider a quick/violent launch), as long as the plane is strong enough. I have routinely used a short, strong zip start for over 10 years to get most of my planes to about 50-100' depending on wind. Its great practice for competitive soaring to start from these altitudes. This includes older, wooden designs like a Challenger (144" span), Grand Esprit (137" span) and Aguila Grande up to moldies such as Supra, Psyko, Onyx, etc.
You can use the same thing for wings, underpowered electrics (which need airspeed up front), etc.

Its all about experience and technique.

JT
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Old Jun 17, 2008, 12:54 PM
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Quote:
Originally Posted by histarter
High start worked well with the Rubber Duck plank. !/6 hp winch would make it vibrate like mad.
Please go crawl back into your own little hole and don't infect yet another thread with your drivel.
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Old Jun 17, 2008, 01:35 PM
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Tigger beim Flitschen mit 200m? (1 min 23 sec)
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Old Jun 17, 2008, 09:05 PM
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Noosa, Queensland. Australia
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thanks for the advise everyone.

amazing launch Richard, I can't wait to get a bungee

steve
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Old Jun 18, 2008, 07:55 AM
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I have a practice bungee, 200 feet of line, and 25 feet of rubber, and I launch my K2 light, Skybird, and Topaz from it all the time, its not a flat horizontal launch like the video above, its like a winch launch, and you even get to do a little ping off the top if its done right.

When they do the bungee's like in the video, are they putting the tow hook way forward?

Steve
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Old Jun 18, 2008, 11:37 AM
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Quote:
Originally Posted by FrogChief
Sailplanes and/or any high aspect ratio (long wing) airplane HATE quick and violent launches. A 25' catapult is for a glass reinforced foam flying wings OR EDF foam jets, etc. Anything with short, stubby wings.

-Sean
No, not really. I have a 25' section of Hosemonster 1/2" rubber with about 75' of 50 pound mono. This is a standard set up for those that want to practice landings. Entirely technique driven, you are trying to maintain as much stretch in the line as you can, then you do a very quick dive and zoom, really just a blip. You can get about 150-200' if you do it right. Any plane set up for a winch can do this maneuver. I can even do this with my Bird of Time, I just can't go so "deep in the bucket" on the zoom.

Go to any big contest on a Friday night and you'll see several set ups on the field. At Visalia last fall I think I counted 6 "upstarts" Friday night.

John
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Old Jun 18, 2008, 10:29 PM
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Go to Bunnings and get yourself 10 metres of the heaviest shock cord. Its about $2.50 a metre.
Sloping at Noosa is awesome. Try Sunshine beach (as far north as you can go) in a SE and Sunrise (Hangglider take off) in an east.
There are some awesome spots around the National Park I am yet to try. Id love to give Lion Rocks/Hells Gate or the Fairy pool a crack in cyclone season.
You will have no trouble launching your chevron. Start with your tow hook about 2 or 3 cm in front of the CG and keep pulling each launch further back untill you get flutter then next launch dont go quite that far back, then you will be achieving max launch speed.
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Old Jun 21, 2008, 09:53 AM
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I replaced my wore out high start with a old exercise bike. It will launch my Spirt to the Bird of Time no problem. I changed the wheel over to a old 20" bike wheel. I have about 1200 Ft. of line so I can fly at many sites. In the normal wind we fly in, I hardly have to pedal at all to launch. I put wheels on it, so I don't have to carry it. If something should go wrong launching, all you have to do is stop pedaling, unlike the high start you can't stop the rubber from pulling. Anyway, it works for me.
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Old Jun 22, 2008, 11:06 PM
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Noosa, Queensland. Australia
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great idea Uproar, I'd love to see a Vid of you launching.
Thanks Steve
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