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Old Jul 01, 2011, 02:45 PM
Detail Freak
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Great post, Joseph!

R,
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Old Jul 07, 2011, 08:39 AM
JuanF
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Tenino WA
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High-start Parachutes:
Is there a minimum and maximum size for parachutes used on high-starts?

I have two parachutes and they are the following dimensions:
10" diameter with 3 7/8" lines at the top of the chute and 19 7/8" suspension lines.
11" diameter with 2" lines at the top of the chute and 16" suspension lines.

I am putting together a high-start using a 100' under 3 meters rubber tubing from Hobby Lobby and will be using Cajun brand 50 lb test fishing line.

I am thinking of making a 15" diameter parachute to use with this set up. My old high-start which I put together many years ago was using the red rubber tubing from Hobby Lobby. I used 40 lb test monfilament fishing line and a pilot parachute from a 24' reserve parachute. I don't remember the diameter of the pilot chute but it was kind of big.

I would appreciate any suggestions or information.
JuanF
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Old Jul 07, 2011, 10:45 AM
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No min, no max that I know of.

parachute is not even required. Just helps to bring the line back to you. Some people just put a streamer on the line so you can see it release from the plane and so you can find it in the grass.
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Old Jul 07, 2011, 07:24 PM
JuanF
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aeajr,
Thanks for the info.
Juanf
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Old Jul 11, 2011, 09:35 PM
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Quote:
Originally Posted by JuanF View Post
High-start Parachutes:
Is there a minimum and maximum size for parachutes used on high-starts?

I have two parachutes and they are the following dimensions:
10" diameter with 3 7/8" lines at the top of the chute and 19 7/8" suspension lines.
11" diameter with 2" lines at the top of the chute and 16" suspension lines.

I am putting together a high-start using a 100' under 3 meters rubber tubing from Hobby Lobby and will be using Cajun brand 50 lb test fishing line.
JuanF
Hi Juan,

I recently acquired a chute that is 14" diameter opened, with 3 3/4" opening at the top and the panels are just under 7" long, with top strings of just under 2" and bottom strings of 12". This is stamped FAI F3J World Championships 2006.

However, I wonder why you are choosing monofilament line?...I do believe that this stretches. The high-start that I have uses a kite string of about 50+ lbs breaking strain and is a colored braid. I could be wrong with the breaking stength of this string, but it could be as much as 80 Lbs. and it is VERY light. If you have ever had monofilament run through your fingers you would choose an alternative.....cuts very deep, to the bone even....

Just my suggestion and information.
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Old Jul 12, 2011, 11:29 AM
JuanF
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Tenino WA
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Hi Sackie,
The line I am using is a braided 50 lb test fishing line. It is Cajun brand name that I got at Cabela's. Although I did use monfiliment line on my original highstart. Where did you get your parachute? I was planning on making up my own parachute and it was going to be about 15" in diameter.
Juan
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Old Jul 21, 2011, 03:45 AM
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Did some HS testing at our field in prep for a contest where we will be offering to fly off matched hi-starts.

The Aerofoam Hosemonster 3M HS tested out at 19 pounds of pull at 3X stretch. And I understand that you can actually pull the hosemonster high starts further than 3X length.

The Pinnacle Large for 3M+ (can't get 'em anymore) tested at 24 pounds at 3X stretch.

I tested each with the same fish scale. Accurate enough to be useful.

At 3X to 4X the weight of the plane the Aerofoam Hosemonster 3M appears to be strong enough for gliders up to about 6 pounds. I would expect it to be excellent for gliders up to about 5 pounds or 80 ounces. My 65 ounce 3.4 meter Supra should do very well on that, even with 15 ounces of ballast for windy days.
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Old Dec 19, 2011, 07:24 AM
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COLD WEATHER LAUNCHING

It is now December, and as Christmas approaches much of the USA has become cold. I flew yesterday and it was below 30 degrees F all day.

Hi-starts, the subjet of this thread, are made of elastic materials that tend to lose their stretch as they get cold. If they get cold enough they will become brittle, and may crack. You will read varying opinions about when you should and should not use a hi-start in terms of termperature.

A friend and I were using his hi-start with snow on the ground. We did fine for a couple of hours but clearly the hi-start was losing its pull as it got colder. But we were still able to launch and there was a breeze that was helping.

By the end of the day, the hi-start had lost most of its elastic pull. In fact it would not contract. That hi-start never recovered its power. It was permanently damged and was thrown out.

My experience says that my hi-starts seem to start to lose their "snap" around 45 degrees F. As the termperature approaches freezing it drops off more.


So, what do you do if your hi-start is you main launching system and your temps drop below freezing?

Electric winches work great regardless of temperature, but they are big, heavy and expensive. A winch, battery and related "stuff" can run $600 for a used set-up and up to $1200 for a new one. Many do not wish to spend that much on a launching system. What else can we use?


I have come across a new product that is hi-start like in its launch and in its cost, but can also be used in cold weather. This is called a OneWinch. www.onewinch.com


Mechanically it sets-up like an electric winch, but you use your body weight and your legs to launch the plane. The kind of launch you can get with a OneWinch is comparable to a hi-start but you don't have the cold weather issues of rubber.

Today a good hi-start can cost $150 or more. A OneWinch is about $220. So think of this as a second hi-start. Certainly it can be used year round, but it will work in the cold. You can read more about it in this discussion thread.
http://www.rcgroups.com/forums/showt...light=onewinch

Starting at post #52 you can read my reports on my experineces with the OneWinch and watch the videos I recorded.

I don't work for this company and receive no royalties or payments if you buy it. I am just sharing my findings about a product that may help keep you flying even when the temperatures start to drop.
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Old Dec 25, 2011, 09:38 AM
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Hi start alternatives can be something like mine. For a long time I have had a Ford starter motor with a long shaft, an inexpensive aluminum drum( alternative here is to look up any local machine shops that might machine you a simple drum,
show them what you want)
I also have a simple solenoid and a simple foot switch with a 12 volt car battery. Mine is built into plywood box with large lawn mower wheels on it and a handle for pulling it around.
I think I spent just over 100 dollars or so about 20 years ago on it.
I had the motor worked on once at a local auto electric shop that rebuilds starter motors, alternators etc
My turn around is simple bicycle axle mounted on a small board staked into the ground.
It's not fancy, nor real powerful like contest winches, but gets the job done.
I purchased the motor as a rebuilt from a local NAPA store.
You might also contact any local auto electric shops, sometimes they have some of these motors, or may know a source. An auto junkyard might be a source, and if it doesn't work, take it to an auto electric shop and get it rebuilt
As for a drum, check out any aluminum dealers or someplace you can find some scrap round aluminum bar stock, and ask any local machine shops unless you yourself have a lathe or access to one and make your own
Solenoids and foot switches can be found at auto parts dealers or a sewing machine shop for a foot switch.
A bicycle axle can easily be found a bicycle repair shop or if you can find an old bicycle no longer being used or that was scrapped out.
It all just takes a little resourcefulness.
Good luck!
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Old Dec 25, 2011, 08:00 PM
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Quote:
Originally Posted by aeajr View Post
COLD WEATHER LAUNCHING
I have come across a new product that is hi-start like in its launch and in its cost, but can also be used in cold weather. This is called a OneWinch. www.onewinch.com
...

Today a good hi-start can cost $150 or more. A OneWinch is about $220. So think of this as a second hi-start.
I'd like to add a qualifier to Ed's note above. You can actually think of the OneWinch as a replacement for several hi-starts. You can use the same device to launch HLG on up to typical moldie planes.

Here's a comment from a recent buyer:
I was able to try the onewinch this weekend. ... It worked amazingly well. I launched a Blaster 2 and then, since that was no problem, also a Climaxx . Even though I am still very bad at launching I could get it up to ~100m in virtually no wind. The OneWinch is awesome -- great work.

Let us know if you have any questions - and I hope everyone here is enjoying some great holiday time.

Tim
OneWinch.com
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Old Jun 09, 2012, 07:38 AM
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One of our members got a Hosemonster 4M hi-start. Man is that thing way too strong. I think we measure it at about 40 pounds pull at about 2.5X stretch and that was about all I was going to pull.
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Old Jun 17, 2012, 07:14 AM
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I've recently been experimenting with a hi-start.

Originally, I was using a cloth-covered bungee of about 10m, with a length of fishing line attached. Worked fine.

Now, I have a 30 silicon bungee ... but, I'm not seeing much increase in performance.

Our field has long grass and slopes away gently. It seems to me that the long grass creates a lot of drag on the rubber and line, such thatthere's a tremendous force required to stretch the rubber properly. Also, the pilot is having to pull from "below" the crest of the slope.

Anyway, more experimenting to come.
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Old Jun 17, 2012, 07:15 AM
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I've recently been experimenting with a hi-start.

Originally, I was using a cloth-covered bungee of about 10m, with a length of fishing line attached. Worked fine ... if modest. The cloth covering restricts the amount by which the rubber can extend.

Now, I have a 30 silicon bungee ... but, I'm not seeing much increase in performance.

Our field has long grass and slopes away gently. It seems to me that the long grass creates a lot of drag on the rubber and line, such thatthere's a tremendous force required to stretch the rubber properly. Also, the pilot is having to pull from "below" the crest of the slope.

Anyway, more experimenting to come.
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Old Jun 17, 2012, 07:58 AM
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Bobbeagle,

It would be very helpful if we knew the characteristics of the silicone rubber you are using. What are its dimmensions? Or where did you buy it - post a link. Based on the length and the fact that it is silacone rather than latex, I suspect you got it from HobbyKing.

If you can get some sort of pull gauge and give us the strength of the pull at 3X stretch, that would be helpful. I usually use a fish scale.

How much line are you using? Typical would be three to four times as much line as rubber. So 30 meters of rubber would get 90 to 120 meters of line. I sometimes use 5 times length for the string.

Finally, what are you launching.?
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Old Jun 17, 2012, 08:37 AM
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Yes, it's the HK blue rubber. Outside diameter 8mm, inside diameter 6 mm, I think.

http://www.hobbyking.com/hobbyking/s...dProduct=10609


I know that it's not stretching much, 'cos I don't walk too far before the tension is quite high ... this doesn't accord with the tension that is required to stretch the rubber "on the bench". The rubber stretches many times its own length "on the bench".

I've got 100 feet of rubber and 400 feet of line. (55lb monofilament)

I've only tried it with a 2 meter glider ... generic "nothing-model".

I'm probably only walking back 50 or 60 feet before the tension is all I can manage with a one-handed grip on the plane. The original setup that I used, was much more compact and most of the rubber/line could be laid out on our cropped runway, if necessary.

I'm going to have someone tension the rubber separately, whilst I walk back with the glider. To be fair, the grass is very long on our field; it's rough pasture that is grazed by a few cattle. And, as I say, the glider-and-pilot end up slightly below the crest of the hill, when the line is tensioned, so the pull is not direct. Oh, yes, and the grass was wet when I tried out the new hi-start.

I'm not complaining about the HK' rubber, that stretches pretty effectively. No, I'm sure that the problem lies in the way that I'm trying to use it.
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