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Old Dec 19, 2009, 10:35 AM
RLW
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Quote:
Originally Posted by aeajr View Post
Nice example of a hi-start launch Mickey.

RLW, those look like two many tow launches, not hi-start launches.
\

Yes but the technique is exactly the same with a high start or tow launch.

The problem with Mickey's technique (a very common one btw) is his arm is bent at the elbow and in front. This makes the weak link of the whole system your arm strength. With my example, once you have your arm locked at the elbow you are using almost zero arm strength to hold tension. Now you can use all your strength to keep your plane in the right position and throw it hard on launch.

The added benefit is your plane does not need to take up precious energy to rotate, as its already launched in the nose up position.

Like I said, there is a reason the pros do it. This technique might seem awkward at first, but once you figure it out you'll never go back. It allows you to safely and easily hold a tremendous amount of tension and launch the plane when YOU want, not when your arm gets tired, or your wings are not level and you can't hold it anymore.
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Old Dec 19, 2009, 12:33 PM
Detail Freak
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I concur with the gentleman above. My form may not be exactly what is descibed above, but it is what I am striving for.
But, change is tough sometimes, use what works for you, and be open minded for improvement, that's what I keep thinking.

R,
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Old Dec 19, 2009, 06:48 PM
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I think that the only reason that I dont put my arm all the way back is that I CAN'T. Will have to use the other arm to help 'load' the throwing arm into the locked position, then grab the radio (from a strap around neck). The 'straight arm method' should not be too bad on a winch as you start with no tension and let it build against your locked arm. Will try and see.
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Old May 11, 2011, 11:18 AM
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Let's bring this back to the top for the benefit of all the new glider pilots.
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Old Jun 29, 2011, 03:10 AM
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Anyone got a good source for thera band rubber? I hear that works well for hi-starts.

Anyone tried the HobbyKing silicone rubber hi-start tubing?
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Old Jun 29, 2011, 04:09 AM
Detail Freak
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Ed-
Try barrington supply for the Theraband tubing.

R,
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Old Jun 29, 2011, 06:45 AM
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I got mine off of an ebay seller. No probs, price seemed good.
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Old Jun 29, 2011, 08:44 AM
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Sources for hi-starts and hi-start rubber

This needs to be updated from time to time.

My favorite, NESailplanes seems to be in trouble. No one seems to be able to get in touch with them, so forget the Pinnacle hi-starts.


OTHER SOURCES

Hobby-Lobby - hi-start rubber or full hi-start packages - well known for quality products
http://search2.hobby-lobby.com/psear...-start&x=0&y=0


Aerofoam - Hosemonster - rubber alone or full packages
reputed to be the best
http://www.aerofoam.com/hosemonster.html


HobbyKing - rubber only. I don't know much about these. 30 foot pieces only so you would have to join them for a larger HS.
http://www.hobbyking.com/hobbyking/s...wer_Search.asp


I found this e-bay listing for theraband
http://cgi.ebay.com/ws/eBayISAPI.dll...m=190544596819
I posted a question to see if the spools are 100 feet continous or if it is pieces. 100 foot of green is $53 including shipping. A guestimate would be that red would be good for 2M, Green for typical 3M, Black for extra strong or larger than 3M. Anyone have actual pull measurements for this stuff?


Tower Hobbies - Low cost - they work but I only recommend these for people on a very very tight budget. Use the HD for 2M or above. Probably Ok to 100" wing span. Standard is for under 2M gliders.
http://www3.towerhobbies.com/cgi-bin...EARCH=hi-start


General guidelines

You can buy latex rubber tubing on e-bay or from other sources, just make sure that whatever length they offer is one piece. You can see offers for 100 feet but it comes as a bunch of 5' sections which would be common use for this stuff. You can join pieces but I would not want more than two joiners on a 100 foot hi-start. There are joiners that can be split so having multiple pieces could be an advantage if you fly on varying length fields.

Assuming you find 30, 50 or 100 foot pieces here are the size breakdowns as I have seen them used. Others may provide different advice. I tend to like my HS a little stronger. You can always pull a little less but if you need more pull and you don't have it you are stuck.


5/16" OD - Standard HS good for about 1.7M up to about 3M or about 65 ounces.

3/8" OD - HS for up to about 3.5M or about 80 ounces. Fine for 2M planes, just don't pull as far.

1/2" OD - Good for up to about 4M or about 100 ounces. May not be good for 2M planes.
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Old Jun 29, 2011, 09:13 AM
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Theraband tubing is available at many physical therapy websites. Try this one, http://www.ptmart.com/category_s/103.htm , I have not personally ordered from them.

Wayne
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Old Jun 29, 2011, 07:55 PM
Detail Freak
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That is a very good price on the Theraband.
I can tell you from experience that the box of 100' tubing is in at least 3 pieces.
So plan on splicing....
R,
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Last edited by target; Jun 19, 2012 at 09:37 AM. Reason: Input not needed
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Old Jun 30, 2011, 02:34 PM
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Quote:
Originally Posted by aeajr View Post
General guidelines

5/16" OD - Standard HS good for about 1.7M up to about 3M or about 65 ounces.

3/8" OD - HS for up to about 3.5M or about 80 ounces. Fine for 2M planes, just don't pull as far.

1/2" OD - Good for up to about 4M or about 100 ounces. May not be good for 2M planes.
The OD alone doesn't tell you enough. What is fundamentally important is the cross-sectional area of the rubber. That area depends on the OD and the wall thickness. Several summaries of the actual dimensions (OD and wall thickness) of the tubing from many sources have been posted on this forum.
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Old Jun 30, 2011, 03:41 PM
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I agree, but the typical for this kind of tubing is 1/16" walls. so, your 5/16" OD has an ID or 3/16. the OD of 3/8 is 1/4" and so on.

the list is a general guideline, not a rigerous assessment.
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Old Jun 30, 2011, 03:52 PM
Detail Freak
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That IS true that most of that sized rubber is about 1/16" wall thickness.
That includes the Theraband, if my memory is correct.


R,
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Old Jun 30, 2011, 09:03 PM
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2 more cents........

Another great source of surgical tubing is:

www.reefscuba.com

They have a pretty good variety of sizes of surgical tubing in both natural and black, are a small Ma-n-Pa owned and operated business, are really fast in getting orders shipped out, and they have been very good to deal with over the phone. Their prices were'nt the cheapest but weren't the most expensive either. The material they sell seems to be pretty good material as well and worth the price. You get what you pay for from them.

I'm currently using the natural color material, 1/4" outer diameter, 1/16" wall thickness, 2- 25ft lengths connected with home-made connectors to make a 50 foot long piece of elastic (I think they can sell a continuous 50 foot piece on request, it might be more expensive), attached to 200 feet of line to launch a heavy 38ounce 2m plane. I stretch mine 50 paces, and if I have to launch WITH a slight breeze, it still has plenty of oomph to get that plane up in the air nicely without floundering, granted not as well as if I launched into the wind, but still, well enough. It's had a LOT, LOT of use with no discernable wear yet for the past year(?). I treated mine with Armourall, but Reefscuba also sells a substance specific to their tubing for UV protection.

I will likely order any other surgical tubing from them also in the future.

That's my 2-Cents. - Paul
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Old Jul 01, 2011, 10:47 AM
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Here are the exact dimensions I received after asking Theraband a while back.

Color/ID/WALL/OD

tan/.062/.031/.125
yellow/.200/.045/.290
red/.200/.057/.314
green/.200/.069/.338
blue/.200/.085/.370
black/.200/.098/.396
sliver/.200/.125/.450

All dimensions above are in inches.

Joseph
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