Aerofoam UAV Systems
Hose Monster Bungees
1. General bungee info.
Hose Monster bungees are made from the finest available mandrel dipped latex tubing. There are only 2 manufacturers of mandrel dipped tubing left in the United States. Our mandrel dipped rubber has the best elastic properties and the most U.V. inhibitors. We also have a special inspection procedure and our own proprietary tolerances, so our rubber is made to our specifications.
2. What is mandrel dipped tubing?
There are 2 processes to make tubing; one is to force small beads through a heated mold under high pressure. The material becomes molten and is formed into tubing as it goes through the mold. This is the extrusion process and it is good for uniformity, speed of manufacture and continuous lengths. The medical and chemical industry uses most of the tubing, so this is the best and least expensive way to make a good product for them. This process does not however produce the good elastic properties that we need. Mandrel dipped tubing is produced by dipping a long rod (mandrel) in molten latex until enough layers are built up to provide the desired thickness. This makes rubber tubing that is fully relaxed.
Our tubing has a small amount of carbon black as a U.V. inhibitor. The outer layers of rubber have the most U.V. inhibitors (5%), so the inner layers can retain a higher percentage of pure latex for its elongation properties.
3 Care and feeding of your Bungee.
You need to protect the rubber from U.V. exposure, sharp objects, chemicals, ozone and heat. All of these things will deteriorate your rubber prematurely. I store mine in a soft ice chest type bag, this has a moisture proof liner and helps the temperature remain more constant. You can store it in a plastic bag and it should be kept in a dark place. I have heard of people storing their rubber in a bucket of water. This is a good method, but not worth the hassle in my opinion. I used the same catapult for over 4 years in Arizona before it started to show some signs of wear. I did have to cut the ends off and reattach the connectors. The rubber gets abrasion damage at the connectors, especially on hard or rocky surfaces.
You should check the rubber for nicks and check the connectors too. The area where the rubber first meets the connectors is where the most wear will show up. The rubber contracts over the edge as it is tensioned. That is why the connector is tapered, but it can still wear at this point. You will eventually have to cut a couple inches from the tubing and re-connect it. It is easier to push the tubing on the connector if you lubricate the connector and tubing with hairspray or for a field repair, spit! It helps to put the connector in a vise when you do this.
303 Protectant is one of the best ways to preserve your bungee rubber.
You can get it at a number of retailers, check online for locations. It is essentially a sunscreen for your bungee. It seals the surface to protect it from ozone too.
If you go to their website, they sometimes have a free sample offer.
There are a lot of rubber treatments and dressings out there.
If you know for certain that a product is good for the rubber, go ahead and use it, if you are uncertain, I would err on the side of using nothing.
I would highly advise AGAINST "Armor All" and any of the similar dressings that leave a greasy film or wet look. These will actually shorten the life of your rubber!!!! If you don’t have personal experience with a product or it isn’t specifically made for rubber, I wouldn’t recommend it. As I stated earlier, I haven’t done anything to my catapult rubber and it is over 4 years old. It was mostly used in Arizona which is one of the worst places to have a rubber product. I once had a "Natural" tan latex surgical tubing High start that started crumbling and cracking after 5 months in Arizona and it wasn’t even summer!!!!
Stay away from "Natural" latex tubing, it won’t last
as long and it usually costs a lot more than our tubing.
4 General Safety.
User assumes all liability and responsibility for using this product.
Aerofoam assumes no responsibility for the use, misuse, or any injuries resulting from the use of this product. We have no control over the end use and safe responsible use is up to you.
5 General Guide Lines.
Don’t use in crowded areas or where children are present or uncontrolled. There is a lot of stored energy in a high start and once you let go of the plane, you can’t stop it. I have seen some nasty string burns that resulted from someone walking into the line while a plane was launching. This actually cut the skin and could have been more serious.
Make sure your stake is adequate for your soil type and check it frequently. Check all the rigging too. A high start doesn’t have the same risk as a catapult. You are hundreds of feet from the rubber and it won’t reach you if something fails. You can endanger others by irresponsible use though. Anyone in the launching path of a stretched high start is in potential danger. If any of your rigging let go, it would whip the string down the launch path and this could cause injury. If the stake let go with someone in front of it, they could be seriously injured. Think about it, a metal spike traveling at around 120 miles per hour!
7 Watch your launch area and keep it clear.
Use the supplied stake (high starts only) for good hard soil. If you have softer soil, use a dog leash anchor, spiral stake or multiple stakes. Some people back up the stake with a large brick tied to the rubber connector. This will take the load in the event of a stake failure. You can do the same thing with a second stake.
8 Line and rigging
Check your line and replace it when it becomes frayed or brittle. It is #18 braided mason line (seine) and can be purchased at home improvement stores like Home Depot. Note: The larger catapults use #42 braided seine. Check the rigging, connectors, parachute for signs of wear. Don’t replace hardware with unknown materials. All the materials in this rig have been tested. The weakest link is the mason line which is rated at 170 to 200 pounds. The rest of the rigging is rated at over 225 pounds. This is about a 4 to 1 safety margin. The average launch develops 30 to 50 pounds of tension. It is much less for 2 meter planes. Unlimited planes can develop more, especially when launching into a headwind.