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  1. #1

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    Alternate Launch Technique Idea

    Living here in west central Iowa (corn and soybean country) where any open land that is not being farmed for crops is tall grass pasture for livestock, it is diffucult if not impossible to find a place to use a high start or winch. (I am starting to go to electric powered gliders...Radian etc) but still want to fly thermal duration in the after work. This has lead me to try to come up with a technique to launch the spirit that I have on the building table and gliders to follow... Bird of Time, Sailaire etc.
    The idea Ive come up with could best be described as a vertical tow. The glider would be lifted to altitude by some means of a helium bag on a line attached to a winch secured on the ground. The release mechanism would be fuselauge mounted in the tail similar to the tow release currently being used by scale ships. A seperate line would desend from the lift bag for the lift line to the glider. At release alitiude the servo would pull the pin, and the glider would fall away to build flying speed, hopefully away from the line to the helium bag.
    I realize this is a radical departure from conventional techniques and am aware the AMA may have some issues with this train of thought. I welcome feedback, positive and negative, about this idea.

  2. #2
    -pkh-'s Avatar
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    RE: Alternate Launch Technique Idea

    Sounds like you'd need an awfully large helium balloon to lift the weight of the sail plane and the weight of the restraining line. You can probably calculate the total weight for a given glider, a certain length of line, and then calculate how many cubic feet of helium you'd need to lift it. I'm betting it's going to be pretty large.

    Seems like an electric powered glider is a much simpler solution.
    Paul - Helis: Two Raptor 50V2s, Venture 30CP, Blade CX2
    Planes: Twist 60, Tribute 36, Two PZ BL P51s, Two F27C Strykers

  3. #3

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    RE: Alternate Launch Technique Idea

    I see no reason it shouldn't work. The only drawbacks I can think of are the size of the balloon needed and the cost of the Helium to fill it. A simple party balloon isn't going to have enough lift to haul it up to a good launch altitude. You're most likely looking at a balloon that is going to have to be at least 4' in diameter, and that's a lot of helium. Not to mention having to haul a cylinder of gas in your car. Not always the safest thing to do even if the gas isn't explosive. If you go this route, be sure you have a safety cap on top of the cylinder.

    Jeff

  4. #4

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    RE: Alternate Launch Technique Idea

    While I applaud your thinking, I think you're going to find this mechanism unwieldly in anything but calm conditions. I'm assuming if you don't have room to set up a winch, you also don't have room to manage an errant large balloon which has pulled some line and the (fragile) glider and wants to drag them along the ground before gaining much altitude.

    If you were willing to let the balloon go (probably expensive), you'd have an easier time. I think PHK is right though it will be a large balloon which needs to lift ~5 lbs of glider plus the rope with enough vigor to not simply drift downwind forever.

    I have visions of fragile glider parts getting engangled into the retrieval line, and maybe getting caught inside aileron/flap slots.

    I tend to really dislike winches myself, and have given some thought to making a droppable power pod which attaches to the underside of a large TD or slope ship with enough down thrust offset to get it to fly straight enough under power. Outfitted with one of those "loc8tor" cat finder devices, I could find it later (or pay a kid to hike in the weeds to get it) If I dropped it and it drifted too far away in the weeds/or corn, or whatever you have.

    I think HL carried something which is strong enough to lift a TD size ship recently, but I can't find it now. Figure put some old lipos in the pod, wrap some straps and/or bungees around the fuselage and trigger it to drop with a servo even use a spare RX and TX if needed to avoid using wires through the main fuselage.
    Arguing with an engineer is like wrestling a pig. Everyone gets dirty and the pig likes it.

  5. #5
    soarrich's Avatar
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    RE: Alternate Launch Technique Idea

    ORIGINAL: spirit pilot

    (I am starting to go to electric powered gliders...Radian etc) but still want to fly thermal duration in the after work.
    Electric is the way to go! This especially goes for older sailplanes like the Sailaire or OLYII types, the weight does NOT hurt their performance, they have lift to burn, they are draggy and the extra weight helps them move around to look for lift.

    I was a purest, wanted nothing to do with electric sailplanes until I tried one, now it's the way to go!
    Rich Border AMA 77727
    Sig Kadet Brotherhood #2

  6. #6

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    RE: Alternate Launch Technique Idea


    ORIGINAL: soarrich

    ORIGINAL: spirit pilot

    (I am starting to go to electric powered gliders...Radian etc) but still want to fly thermal duration in the after work.
    Electric is the way to go! This especially goes for older sailplanes like the Sailaire or OLYII types, the weight does NOT hurt their performance, they have lift to burn, they are draggy and the extra weight helps them move around to look for lift.

    I was a purest, wanted nothing to do with electric sailplanes until I tried one, now it's the way to go!
    I agree with soarrich. I re-read the first post and now realize Sprit Pilot is NOT necessarily a purist (like me)

    There's certainly no real detriment to carrying the weight of a good motor and battery within a large TD ship. With the folding props you won't even know its there when thermalling.
    Arguing with an engineer is like wrestling a pig. Everyone gets dirty and the pig likes it.

  7. #7

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    RE: Alternate Launch Technique Idea

    Thanks for the input guys. Looks like its back to the drawing board.

  8. #8
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    RE: Alternate Launch Technique Idea

    No chance of flying with a friend and piggybacking? I do it with a Tiger 2 and a Spirit and they climb to almost speck altitude. I could have a bigger mothership, though, cause it takes a while to climb
    Modify, personalize, upgrade

  9. #9

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    RE: Alternate Launch Technique Idea

    I fly in the same type of area, lots of room but everything is corn or beans. Hi-start is out of the question, just one retrieve through tall beans or corn will end that idea although it will work during the winter if you have a wheat field handy. Stubble from a harvested bean or corn crop snag it too much to use them in the winter. A zip-start might work with the right glider, I have not tried that. Electric is the easiest ,you can't see the prop for most of the flight and you don't take a chance of landing in a corn field. A winch will work if you run the line down to the turn around after release. Put a small ball on the line to stop the chute from going through the turn around. You can tell when it is at the turn around by the sound of the winch motor. It's just a long walk to the turn around for each retrieve. I set up on a field road and use my truck to retrive the line. If you can get past looking at a prop on a glider, electric works best at that type of field.

  10. #10

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    RE: Alternate Launch Technique Idea

    My first pc. of advice is to spend some $$ and take a ride around and look for some dirt roads running in the right wind direction for use with a Highstart. Landing in a Large field of Corn is not fun so the road will come in handy anyway. The Last Few Years I have been Mentoring a group of Middle School Kids in a Science Olympiad Event Called Balloon Launched Glider ( I was also the Judge at the State Contest ) . You are going to need a Pretty Big Balloon to Lift up a 30 oz Glider. We used an under inflated 36" dia balloon to launch these little few ounce gliders ( 20-24 inch dia balloons) The real problem is when you "pull the pin" on the Release you are launching with Zero airspeed, so you are going to lose a lot of altitude just getting the plane some airspeed so it is actually flyable. BTW the typical Latex balloon is pretty fragile when blown up a pine Needle is like a very Icepick.

    So what's my advice?? Get yourself a Highstart and look for some suitable not well traveled Roads. The High Start is a really good Launch system for a Spirit, it's not really very expensive and it's doubtful you fold the wing during a Launch.

    If what you really want is to be able to fly out over the Corn/bean fields in your backyard then start looking for a Light Weight Electric Glider. I have flown a few, and with the Motor Off and the Prop Folded it's easy to forget that it's not just a glider. One of the ones I flown was a full house 2M that weight in at 27.5 oz. If I remember correctly you'd have to build very carefully to get a Spirit built to 27/28 oz.

    Hope this helps a little.

    Jim B

  11. #11

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    RE: Alternate Launch Technique Idea

    Guys, there's no need for helium at all - as long as you're in a suficiently cold area and with good sunlight. Check this out:

    http://en.wikipedia.org/wiki/Solar_balloon
    http://www.youtube.com/watch?v=FKIm7anMhME
    http://www.youtube.com/watch?v=3mNuzRnZoPg
    http://www.solar-balloons.com/index.html


    AndrΓ© F. A. Carvalho
    AndrΓ© F. A. Carvalho (ParnaΓ*ba, PI, Brazil)
    cmte.carvalho.phb@gmail.com

  12. #12

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    RE: Alternate Launch Technique Idea

    You could make this work, but what a lot of effort to get in the air! Could you set up a high start next to a county road that gets maybe two cars an hour?

  13. #13

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    RE: Alternate Launch Technique Idea

    Not sure how practical or hard it will be, but I really like the balloon idea myself. I see car dealerships with pretty big balloons all the time, so they might know where to get them. Even in some gusty conditions they seem pretty solid. Also, in even the slightest breeze the glider will hang away from ground line if on a short line. I say put in an extra servo for the release, use a short line from balloon to glider, get a large spool of spectra fishing line for ground-balloon line, LET'ER RIP! That's just me though . If you do it, GET VIDEO!!! Let it up 2-300yards...bombs away!
    MMmm..Piepants..


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