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Old Apr 18, 2008, 12:15 PM
Registered User
Portland, Oregon, USA
Joined Mar 2007
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Weather Balloon Launching System for RC Sailplanes

I was just thinking about ways of launching a sailplane and thought a weather balloon would be a good way to do it. This is what I was thinking: Youd have your balloon with some kind of mount that would hold your plane nose down. This mount would have a release mechanism that would be connected to a desired length of very light and strong Kevlar fishing line that would be then go into a level wind fishing reel or some other winch system that is mounted on something heavy or bolted or clamped to something that is. So you would have the desired altitude in line pre drawn-out and piled neatly on the ground then rig up the plane to the balloon and let it go. The balloon takes the plane up until it reaches the end of the line and with that tension on the line the release mechanism is activated and the plane is in free fall. A short dive is made to get the plane up to flying speed then pull out of the dive and start soaring. With a big enough balloon you could make a rig that would hold any number of planes and have competitions to see who can stay up the longest from a controlled altitude. Or it could just be an efficient way of getting multiple people flying at once. I think the mane disadvantage to this would be having to fill the balloon other there than that I cant think of a reason why not to do this. What do you guys think? Has this been done or do I need to start marketing this system?
Chears,
Nate
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Old Apr 18, 2008, 01:34 PM
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rogerflies's Avatar
Thomasville, GA 31792
Joined Apr 2002
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Having a nearly invisible obstacle from the launch area to the balloon comes to mind as a possible downside.

I'm not sure how well you could keep several planes from "interacting" with each other during the ascent and immediately after the release.

Windy conditions would limit the altitude reached, unless the buoancy of the balloon was much more than the weight/drag of the planes.

Perhaps a continuous loop with several attachments at intervals would work better. A "trip" would release the plane when it reached the turnaround pulley at the balloon.

Roger
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Old Apr 18, 2008, 01:50 PM
Yep, Naza-controlled Tricopter
tonyestep's Avatar
St. Louis
Joined Apr 2002
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For a page showing this launch system in action, see:
http://members.shaw.ca/sonde/launch_1.htm
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Old Apr 18, 2008, 03:59 PM
I just wanna fly
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USA, CA, San Luis Obispo
Joined Jul 2005
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I would be more afraid of a release mechanism failure!

Just imagine watching your plane(s) floating up, up and away!!!

Yikes!!!!
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Old Apr 18, 2008, 04:25 PM
May the Wind Always be Good
Webster, Minnesota
Joined Feb 2007
493 Posts
Yes that will work BUT only on wind less days .. I have used this on wind less days with a kite so i could get my 2 mintets time in the air after relese from the balloon ...it is a 2 man job...2 lines one for kite and one on the balloon...Any wind makes the balloon unmanageable ....Sounds good but not practical.....May the Wind Always be Good .... Used a down rigger clip so just a jerk on the line and the two were free of each other
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Old Apr 18, 2008, 05:05 PM
Phil.T-tailer
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Devon, UK
Joined Jun 2003
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Quote:
Originally Posted by tonyestep
For a page showing this launch system in action, see:
http://members.shaw.ca/sonde/launch_1.htm
That is soooooooooooo cool
what a great project!
Phil
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Old Apr 19, 2008, 03:28 AM
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Thomasville, GA 31792
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It's NOT going to be so cool when the authorities decide our little toy planes can be used to deliver bad things precisely on target with a real-time video feedback. That's when they'll slap some serious restrictions on how, when, where, what, and IF we fly.

Just because we CAN do stuff like this doesn't mean we SHOULD. And we'd be better off if we didn't post it on the net when we did it.

Rant off.

Seeing all the expensive equipment, it seems like an airframe capable of withstanding more than 7g would have been used.

Roger
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Old Apr 19, 2008, 07:19 AM
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United States, CA, Folsom
Joined Jul 2007
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While not exactly a weather balloon launch, an interesting variant was done about 25 years ago in Michigan. Cal Posthuma had a Sagitta 900 that was released from a regular, man-carrying balloon.

Total win-win. The guy that got to release the sailplane from altitude got a balloon ride, Cal got the launch of a lifetime.

JT
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Old Apr 19, 2008, 09:04 AM
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United States, MA, Waltham
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I've seen a much easier way to get your sailplane to extreme altitudes. You launch normally, near the middle of the day, and find one of these things called a thermal. If it's a good one, within one to five minutes you'll be popping the spoilers so as not to go too high. :-p
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Old Apr 19, 2008, 11:54 AM
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Portland, Oregon, USA
Joined Mar 2007
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Quote:
Originally Posted by rogerflies
Having a nearly invisible obstacle from the launch area to the balloon comes to mind as a possible downside.

I'm not sure how well you could keep several planes from "interacting" with each other during the ascent and immediately after the release.

Windy conditions would limit the altitude reached, unless the buoancy of the balloon was much more than the weight/drag of the planes.

Perhaps a continuous loop with several attachments at intervals would work better. A "trip" would release the plane when it reached the turnaround pulley at the balloon.

Roger
To address your first concern, the idea is that after the plane is released the balloon would be released back down by someone not flying or even by an automated system. As for keeping the planes from tangling that would be done with a fame that would hold the planes in position. This frame would also hold the planes in such a way that they would not interact with each other when released. As for wind, yes that would be an issue that would determine how high you could launch from. Your idea of a continues loop is interesting too. It would work like a ski lift, right? With that setup you would defiantly want to have it off to the side of the area that was going to be flown in so there is no chance of running into the line or balloon.

Quote:
Originally Posted by slozuke
I would be more afraid of a release mechanism failure!

Just imagine watching your plane(s) floating up, up and away!!!

Yikes!!!!
There are scary consequences for many possible mechanical failures in our world. Its just a matter of proper design and maintenance to greatly reduce the risk of failure.

Quote:
Originally Posted by lincoln
I've seen a much easier way to get your sailplane to extreme altitudes. You launch normally, near the middle of the day, and find one of these things called a thermal. If it's a good one, within one to five minutes you'll be popping the spoilers so as not to go too high. :-p
Yes, I am aware of the concept of thermaling. My idea is for when there arent any to be found or if you want to start from the same altitude every time so you can have a constant when evaluating your skill as an RC pilot. Im not trying to say that with out such a system you cant evaluate your skill but it shure helps to take out as many variables as you can.

Well any way it was just an idea I have been thinking about for a while and thought Id see if ed float. Thanks for the input guys.
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Old Apr 19, 2008, 04:58 PM
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Minneapolis, MN
Joined Sep 2004
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Quote:
Originally Posted by rogerflies
It's NOT going to be so cool when the authorities decide our little toy planes can be used to deliver bad things precisely on target with a real-time video feedback. That's when they'll slap some serious restrictions on how, when, where, what, and IF we fly.

Just because we CAN do stuff like this doesn't mean we SHOULD. And we'd be better off if we didn't post it on the net when we did it.

Rant off.

Seeing all the expensive equipment, it seems like an airframe capable of withstanding more than 7g would have been used.

Roger
In the US, autonomous aircraft are already prohibited from entering controlled airspace. But this fellow is from Canada and they follow another set of rules altogether.

It is a very impressive project in any case.

/Adam
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Old Apr 19, 2008, 06:16 PM
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Minnetonka, Minnesota, USA
Joined Jan 2005
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Similar, but way different...
When I was a kid in the mid to late '50s, my dad made a little uni-cylce dolley that would ride a string. A 2.5 to 3 inch v-groove pulley, a "keel" suspended off the axle like a one-sided bicycle fork, and a lead weight at the bottom. The V-groove straddled a string and tracked along the direction of the string. The low CG of the underslung weight kept the cycle up right.

Then he took my balsa glider, the dime store chucker variety, drilled a hole through the nose, slipped the nose into a slot in the lead weight and cross pinned it. He attached a light monofilament line from a spincast fishing rod & reel to the pin, then daisy-chained it on to the unicycle for a final, firm connection.

Finally, he attached a parachute about 18" in diameter to the unicycle.

He'd launch a kite and get it w-a-y up there. Then he'd place the unicycle on the kite string and inflate the parachute. The chute would pull the unicycle, glider and pin pull-string up the line. When it all reached the kite, he'd give the pin-pull line a good jerk to release the glider.

The first time he did that and I watched my glider fly away, I freaked. "DAD !!! Whatch doin? That's MY glider! If you want to throw toys away, get your own toys!". He tried to tell me this was great. I wanted the glider to fly, and now it was flying longer than it ever had before. Sure Dad, last seen leaving South Dakota, heading for Minnesota. Even when he went to the store and bought more gliders, I never bought his story. Well, much, much later I did... but not back then. Not that day.

After the pin was pulled, he'd use the fishing reel to pull the unicycle back down for another launch. Whether it stayed on the line when the pin was pulled, or fell off and hung from the parachute... it didn't matter. Either way he'd reel it in. Sort of the 1950's version of a lauch line retrieval system.

Relevance? Well maybe none... I guess I hi-jacked the thread a little. It's not a balloon, and it would take a pretty good size kite to lift a large sailplane... but hey, maybe an HLG?

Regards,
Tim
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Old Apr 19, 2008, 09:05 PM
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Russian Federation, Sakha, Yakutsk
Joined May 2006
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Quote:
Originally Posted by rogerflies
It's NOT going to be so cool when the authorities decide our little toy planes can be used to deliver bad things precisely on target with a real-time video feedback. That's when they'll slap some serious restrictions on how, when, where, what, and IF we fly.

Just because we CAN do stuff like this doesn't mean we SHOULD. And we'd be better off if we didn't post it on the net when we did it.

Rant off.

Seeing all the expensive equipment, it seems like an airframe capable of withstanding more than 7g would have been used.

Roger
No worries. A Government SHOULD fear it's people.
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Old Apr 20, 2008, 02:11 PM
Full Scale Better! UOHHHH!
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United States, TX, Lytle
Joined Dec 2006
396 Posts
Hey guys, this is America, we did elect the people we call the "Government", shouldn't we take more time to insure that OUR Government knows what WE want??? ....of the people, by the people and for the people?????
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