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Bungee Rubber Tubing


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In earlier days, I had a bungee for my gliders, incorporating 30m of 6mm od rubber tubing, along with the nylon line.  Looked it out the other day, and it had completely decayed.  I'm now looking for a replacement.

Having looked (on eBay from Chinese suppliers), similar rubber tubing is being offered, mainly in 1metre lengths, sometimes a bit more.  There are lots of suppliers of the braided solid bungee rubber, but, in my recall, the braided solid stuff is a bit too powerful for lightweight gliders- I don't want to pull the wings off!!

 

Has anyone any suggestions as to any present sources for rubber tubing?

 

Thx in advance!

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I found this on Ebay:

 

Bungee Rubber

 

Yes its a 10m maximum length but you could join lengths reasonably well. 

 

That said, if you don't mind the surgery, a small outrunner in the nose and a small capacity Lipo wouldn't add much weight and would make solo operation a lot easier. 

 

I do appreciate the purity of a "pure" glider though, but it's an option. 

Edited by Matt Carlton
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Not much, if anything, available in this country.

 

I have three different sizes (diameters) of rubber from EMC Vega in Germany. They are specialist suppliers in all things related to glider launching.

 

It is expensive but is very durable (my oldest is 15 years old or more).

 

Latex surgical tube (the beige coloured stuff) is traditionally what bungee systems used, I have some but it's deteriorating slowly (kept away from UV in a bag dusted with talc as it can stick to itself).

 

The cotton braided stuff can be used for light gliders but it can be too powerful, a difference between the latex and the cotton stuff is that the cotton hits a stretch limit because of the braiding where the latex can stretch almost infinitely.

 

Gliders with electric motors in the nose became popular (fit a battery and launch versus walk 150 metres, stick a stake in the ground and walk back!) which eventually manifested in the competition world with F5J replacing F3J (winch launch).

 

I still launch F3J gliders on a bungee for landing practise and there is no other use for these gliders apart from flying them on the slope for fun.

 

     Cheers

 

         Gary

 

 

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It's a bit of a shame that most of the FAI pure glider classes have been made somewhat obsolete by new electric alternatives. I see that the FAI have F3g as a provisional alternative to F3b. 

 

My only competition experience came right at the end of the old "Open" class with a "Selestra" right around the same time that moulded models took over and 100s became the Tracker comp!

 

 

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I did wonder about making a bungee from braided shirring elastic but I'm not sure how well it would work. It is quite stretchy though, I used to steal it from my mother's sewing basket in my youth to launch KK free flight gliders. With some success, it seemed at the time anyway! 

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For what it's worth, glider guiders have been searching for an alternative to quality light brown surgical rubber tubing for decades - certainly since I started out with gliders back in the 1970's.  AFAIK......nothing works as well as surgical rubber tube, cotton covered bungee cord being particuarly hopeless as I found out for myself years ago. Unfortunately, proper surgical rubber deteriorates very quicky in use and almost as fast when stored away despite all the standard precautions.  Dogs are attracted from miles around to come and chew through your carefully staked out bungee.

I suppose something could be cobbled up for small or very light models, but for anything else the good stuff is what you need. Where to get it, though? It was difficult enough to source back in the day. EMP models (the late Dick Edmonds) was our go to supplier. Some black tubing came on the market for a while but was never as good. I see that surgical rubber is sold for catapults, but whether it has the progressive stretch qualities for glider launching I wouldn't like to say.

Perhaps a towline if you have an athletic youngster to press into the job?

Personally, I'd go with a motor and folding prop to launch these days.

Edited by Cuban8
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Have a look for Theraband tubing used for physio exercises.

I have been using the red tube for an F3 RES glider and it works well.

Various power levels are available and the specification is given for each Colour in terms of its force at 100% elongation. 

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The big advantages of bungee are simplicity & single person operation. I often used to use cotton covered bungee cord when I had no one to hand tow or the power winch wasn't available, whilst it wasn't as good as surgical tubing it was easy & cheap to obtain. 

The biggest disadvantages are need for a very long launch area approximately 200mtrs & in line with the wind that's relatively free from Joe public & his dog. Actual launching plus bungee & line retrieval don't mix well with the average club's other type of model operations, especially helicopters.

IMO, modern self launch (motor & battery) power methods have wiped out the disadvantages whilst maintaining the advantage of independent operation at a stroke.

  

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On 23/06/2022 at 16:01, Matt Carlton said:

I did wonder about making a bungee from braided shirring elastic but I'm not sure how well it would work. It is quite stretchy though, I used to steal it from my mother's sewing basket in my youth to launch KK free flight gliders. With some success, it seemed at the time anyway! 

Hmmmm

What would you do with a small glider?

Something between 100 and 250 grams. ... and wanting to experience that "something" of a glider without a motor.

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On 25/06/2022 at 09:02, perttime said:

Hmmmm

What would you do with a small glider?

Something between 100 and 250 grams. ... and wanting to experience that "something" of a glider without a motor.

I use 1/8" flat rubber strip that's been retired from my rubber powered models to make up a short bungee system to launch a couple of my small DLG's. It works with a rubber to line ratio of 1:3, but I don't think it's particularly critical.  The downside is that the rubber won't last too long in UV light, although it's easy to knot if it breaks.

I've also tried 1/4" flat rubber, but for very lightweight gliders the 1/8" works better.

 

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I have a recollection of being told that bungees for full size glider launching were traditionally stored under water in the dark although the one we had at Dunstable in the late 70s/early 80s was simply laid on a shelf in the parachute store [a dry but windowless room].  As these were [likely?] to have been natural latex based perhaps this might be the answer to delaying degradation?

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By coincidence I googled catapult rubber UK about the same time as Paul with similar results. There are various dia to be had but the max length I've found is 10 m. Probably fine for small models but we used to use 30m elastic section plus 120m line for BARCS comp size models.

In the single channel era I used 3/16" & 1/4" flat FF model rubber + line to launch my KK Chief & RCM&E Clio (free plan). Also once got some sq section rubber (either 3/16 or 1/4 - can't remember which) catapult rubber from a hunting & fishing supplies shop. Mike Woodhouse can supply FF rubber that would be suitable for small models.

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In the 70s 5/16" sq rubber was quite popular. It gives a pull duration similar to surgical tube and the brute strength that can be obtained via Bungee chord (short on extension compared to the alternatives).

 

This rubber in that period was often used by fisher men, for catapults (bait I understood). It could be that it is still available.

 

The real trouble with bungees was the large fields needed for a decent sized assembly. The second problem was a rubber snap, that would take some chasing in windy weather, as the shute carried it downwind. Yes, electric motors solve that problem, although less skill is needed with electric to get an extended flight.

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