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Old Oct 26, 2003, 07:37 AM
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Marlborough, Massachussetts, United States
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My bungie hi-start has 100' of 3/16" bungie cord and about 200' of line. It's Hobby-Lobby's Standard Bungee Launch:
http://www.hobby-lobby.com/histart.htm .

Eventually I will get a better hi-start, but this one is good enough for now. The club winch is available most weekend mornings, which is when the field is more popular, and I have free access to it at those times.

My eventual goal is to fly a DAW Ka6E (117" span, 85 ounce weight): http://www.davesaircraftworks.com/giant.htm#ka6e
I don't think I'm strong enough to use a hi-start that would pull that one up so I need to learn to use the winch eventually. However, as yesterday's Spirit crash indicated, it's going to be a while before I'm ready to fly that plane.
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Old Oct 26, 2003, 08:15 AM
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Punta Gorda, FL
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Brian,

The tow hooks on the Ka6E should be mounted on the fuselage sides, close under the wing to avoid violent pitch up. A bridle is needed and should run loosely through the normal launch ring.
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Old Oct 26, 2003, 08:51 AM
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Thanks Ollie. I think I understand what you are describing. There would be one hook on each side of the fuselage, and a short line with a ring on each end and some kind of attachment point in the center for the winch. Is that right?
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Old Oct 26, 2003, 09:26 AM
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The short line with the rings at each end has to be able to slide through the ring that is attached to the end of the winch line. if you don't let the yoke line slide through the winch line ring, you could run into yaw induced roll during the launch and a yaw-roll oscillation could develop. If you tie the yoke line to the winch line or ring, then if the model yaws during launch, the tow hook on one side of the fuselage will be pulled harder than the other and the plane will yaw. The yaw will be converted into undesired roll by the dihedral. If the yoke line slides through the winch line ring, then your rudder will be fully in control of yaw during launch.
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Old Oct 26, 2003, 09:39 AM
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Marlborough, Massachussetts, United States
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I understand now. Sounds like a good solution. I'll keep that in mind for when I eventually get a Ka6E, though it might not be until next year. I want to be very comfortable launching a 2M R/E sailplane before moving on to a 3M A/R/E scale sailplane, even if it is made from EPP.
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Old Oct 26, 2003, 10:41 AM
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Quote:
Originally posted by BrianRickman
My bungie hi-start has 100' of 3/16" bungie cord and about 200' of line. It's Hobby-Lobby's Standard Bungee Launch:
http://www.hobby-lobby.com/histart.htm .


My eventual goal is to fly a DAW Ka6E (117" span, 85 ounce weight): http://www.davesaircraftworks.com/giant.htm#ka6e
I don't think I'm strong enough to use a hi-start that would pull that one up so I need to learn to use the winch eventually. However, as yesterday's Spirit crash indicated, it's going to be a while before I'm ready to fly that plane.
One of the guys in our club uses 3/8 bugee to launch his spirit. It has a very explosive delivery of power, much more so than my 1/2" tubing hi-start. It puts his Spirit up, but I find it very abrupt, almost startling.

That is a very cool looking sailplane. I had never seen anything like that in foam. I have bookmarked it.

As for being strong enough to launch the 117" plane, I guess using the winch, you will have to put it on a trolly and pull it off the ground. I have seen that done with a winch. I have never seen it done with a hi-start althought I guess it could be done.

Good luck to both of our Spirits!
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Old Oct 26, 2003, 10:50 AM
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Quote:
Originally posted by BrianRickman
I understand now. Sounds like a good solution. I'll keep that in mind for when I eventually get a Ka6E, though it might not be until next year. I want to be very comfortable launching a 2M R/E sailplane before moving on to a 3M A/R/E scale sailplane, even if it is made from EPP.
Brian,

May I suggest, as a fellow Spirit pilot, that you add the spoilers to your spirit. It is not hard to do. The instructions show how to do it with one servo in the the fuselage and string running through the wings.

I did it by putting servos in the wings, but it doesn't really matter how you do it. Learning to use the spoilers is another growth step you can take with the Spirit on the way to your 3 meter plane.

I was amazed at how much the spoilers help with the landing. You can land much more smoothly and in much shorter distances with the help of the spoilers. I found this especially helpful in gusty wind conditions.

I spent one day launching and landing in 15-20 MPH winds solely for the practice in wind. On the first day I did it without spoilers. On the second I used the spoilers. What a difference.

As you progress with your 2 meter plane, add spoilers. You will be very happy you did.
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Old Oct 26, 2003, 10:52 AM
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Yes indeed. I hope your Spirit soars again soon.

I've found that if I stretch my hi-start fully (about 150') it is very hard to handle. Pulls the plane out of my hand before I have a chance to throw it properly. However, if I limit the stretch to 100' or so, it is much easier to work with and still gives a decent launch. Of course, it works better with a bit of wind then in absolute calm conditions.

For launching a big glider, I'm not so much concerned about throwing it hard enough, as I am about holding it over my head with 20+ pounds of force from the hi-start pulling it forward. I have successfully hand launched a 5 pound powered plane (big-t). Was not as easy as with a smaller plane, but not too difficult.
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Old Oct 26, 2003, 11:09 AM
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Are you saying you have a bungee hi-start that has 100' of bungee and you stretch it back 150'? No wonder you can't hold it. That must be putting 20+ pounds of force on a 2 pound plane. That would probably be enough to launch that big sailplane.

How do you keep from crushing the fuse holding the plane? I am 6/2" and I am not sure I could hold that.

I can see why you have had trouble controling the launches. The recommended pull on the Spirit is about 8-10 pounds. I think you are over pulling that bungee. You would pull 5/16 surgical that far, and perhaps even further, but not bungee.

Having used my friends 3/8 bungee launcher I don't think we ever pulled it more than 50% of its length and had a hard time holding the plane at that. Of course his is stronger than yours, but still.

I am not being critical, I am just giving you food for thought. Try a shorter pull. With your recently improved techniques you may find your launches are just as high with less stress on you and the plane.
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Old Oct 26, 2003, 11:49 AM
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That is what I was saying. I may be over estimating the distance I'm pulling it. I'm not sure exactly how long the field is.

When I stretch it a shorter distance, which I am estimating at 100', it works much better then when I stretch it to the limit. I did notice that the winch launches seemed gentler then the hi-start launches, even with the reduced stretch. When I have another glider to play with, I'll experiment a bit more with varying the amount of stretch. Probably should get a fish scale so I can get a more accurate picture of how much pull I'm getting. Seems like there's always one more tool that I need .
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Old Oct 26, 2003, 12:03 PM
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Yep! Always some new gadget.

I love this hobby! Don't you?


Here is a hi-start launch of a hand launched glider - the fling

Fling - A small RC glider ENG - An evening flying with high-start (Sony A65) (6 min 12 sec)
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Old Feb 05, 2004, 10:30 PM
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Quote:
Originally posted by BrianRickman

On my fourth and final launch something went terribly wrong. I think maybe there was a strong gust of wind from the side, or maybe I just dumb-thumbed it, not really sure. Anyway, it got up about 15 feet and then fliped over so the nose was pointing down. I tried to save it but just couldn't turn it over fast enough. There was a loud bang and a shower of balsa wood. The wing was a total loss. The rubber bands cut through the center section, and the tips shattered. Amazingly enough, the fuse and tail look fine. Would not have believed that was possible with a balsa plane. I have not tested the radio gear yet, though I'm hoping it all survived as well.

I ordered a "Gentle Foamy" a couple days ago, just in case something like this was to happen, so I'll be back in the air again soon.

Maybe after I've flown the foamy for a while I'll build a new wing for the Spirit. Or maybe not. I only paid $35 for this one, and it came with two standard servos. I think I got $35 worth of value from it as I have found out that I really enjoy flying sailplanes.
BrianRickman

Did you ever get your Spirit back in the air?

As you will recall I crashed mine a few weeks before yours. I just finished rebuilding mine and am waiting for good weather to fly it.

How about that Gentle Foamy. I am very interested in your experience with that plane. Thinking I might get one.
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Old Feb 06, 2004, 10:06 AM
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Marlborough, Massachussetts, United States
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aeajr,

I still have the fuse from the Spirit, but the wing was damaged beyond the level at which I am willing to make repairs. I may build a new wing for it some day...

The Gentle Foamy is great. I think we've exchanged emails about it already, but just in case that was someone else... It launches very easily on a 2 meter hi-start or a winch. It has a very strong wing so full pedal winch launches are fine, though certainly not necessary. It flies slowly with a bit of up elevator trim. Lands easily. Flying it is generally easier then the Spirit, though it doesn't stay up quite as long. My AUW was 35 ounces with a 1400 Mah nicad pack, two standard servos, a Hitec 555 receiver, and 2 ounces of lead in the nose.

A couple weeks ago I decided to try it with a motor so it now has an Atomic Force geared 3.8:1 with a 12x8 folding prop on the nose, and a 6 cell CBP 1800 Mah Nimh pack under the wing. AUW is now 45 ounces. I have not flown it in this configuration yet, but I'm hoping to try it out this weekend if it stops snowing long enough.
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Old Feb 06, 2004, 04:20 PM
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sounds good.

Yes you and I did exchange e-mail a while ago. I had forgotten.

I had not heard of anyone launhcing the Foamy from a winch. Full Pedal? That is impressive.
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Old Feb 06, 2004, 05:04 PM
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You can hear the winch motor strain as it gets near the top of the arc .

The wing is built from three pannels (flat center section with poly tips). The wings have hard-wood spars top and bottom, a balsa trailing edge, and plywood joiners for the tips. It's very strong.
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