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Jun 08, 2002, 08:21 AM
CMFC Secretary (UK)
BioHazard's Avatar
With TwinJet on board for scale....
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Jun 08, 2002, 08:23 AM
CMFC Secretary (UK)
BioHazard's Avatar
Underside....

Mechanism is a piece of hardened and annolised (spelling?) steel.

Bolted to the wooden board at one end with 3 bolts.

Mid way there is a bolt protuding through the wood as the release button.

At the far end, another bolt protudes through the wood as the bunjee holder. This bolt has been smoothened down with a Dremel tool to aid an easier release.
Jun 08, 2002, 08:24 AM
CMFC Secretary (UK)
BioHazard's Avatar
At the bottom of the picture of the release 'button'.

At the top of the board is the bolt that holds the bunjee.
Jun 08, 2002, 08:26 AM
CMFC Secretary (UK)
BioHazard's Avatar
Did I mention it was very portable ??

Needed when you have a sports car with no luggage space. I can still get all my flyingkit, 2 models and the bunjee board into my lotus elise.....
Jun 08, 2002, 08:35 AM
CMFC Secretary (UK)
BioHazard's Avatar
Fish Scales as per local tackle shop.

This 'Salter' set cost me 2.95. The go all the way up to 14lbs, which will be far more than the models I use.

My Kyosho F16 normally has only 8lbs of tension, although my biggest A-10 (8lbs weight) has has 10lbs of tension.
Jun 08, 2002, 11:05 AM
Registered User
kushal_22's Avatar
Since we are showing our "works of art" here is mine. I made mine a little shorter as well so i could get mine in my car and be able to carry it myself.
Jun 08, 2002, 04:05 PM
Registered User
mtayl's Avatar
Looking good Malcom!

Has anyone launched a Wing from one of these things? I'm getting into the 50-70oz AUW which is obviously way too heavy to consistently launch with a throw. I'm looking at way to get a heavy Zagi 3C or Slayer off of the ground. I could use a simple bungie launch, but I want to be able to launch my other planes as well so I'm looking at the pedal launcher.
Jun 08, 2002, 04:18 PM
Registered User
Peter W's Avatar
erm nice board.....bout you can't ANODISE steel: it would only work on aluminium ( like maglites) and would look shiny and would scratch if you tried to ( also like maglites) . that just looks like grey paint to me......
or is it electrp-static painting?
these things are neat the way they shift the awesome tension of the bungee onto the model without damging the hook on the plane. the pedal bit is very cool too, i need a plane to use this for!

Pete
Jun 09, 2002, 03:22 PM
CMFC Secretary (UK)
BioHazard's Avatar
The board itself os pine - painted to waterproof.

The steel itself is the strip of metal underneath that has all the holes in it. I've ruined two drill bits on it, whilst trying to expand the diameter.

POP QUIZ... if it isn't ANODISE, what is the name of hardening steel ??
Jun 09, 2002, 03:42 PM
Tacoma, WA, USA
William A's Avatar
Anybody else having bad visions of that anchoring stake loosening out of the ground and come shooting back at you like an arrow ?.
Jun 09, 2002, 03:56 PM
Registered User
Peter W's Avatar
the only way of making post-formed steel harder is to temper it. heat it up to a cherry red colour then plunge it in to water or oil to change the temperature quickly. this alters the grains on the outside of the steel and makes for a harder coating.
if you heat a bit of steel, you should see some bands of colour, or i've even seen a saw with teeth blades with the oily looking colour bands on them, indicating that the working area has specifically been hardened. you get a varying degree of hardness depending on how far the colour band has moved along an area during heating.
also, if you repeatedly BEND a piece of steel, the bent area will become harder! other metals have this property too, work hardening they call e'm
That's if i remember it correctly from last years technology lessons.....

Pete
Last edited by Peter W; Jun 09, 2002 at 03:59 PM.
Jun 09, 2002, 05:02 PM
CMFC Secretary (UK)
BioHazard's Avatar
You win.... tempered it is. If I could have only could have remembered that earlier.

With regard to that peg coming shooting back at you-

I use a 12" peg at the bunjee end and a 7" peg at the board end.

Since I fly from a concrete surface, I have a number of locations that I can 'plug' into. The shearing force required to remove such a peg is well above the structural strength of the bunjee. ( i.e., the bunjee is more likely to snap than the peg come out )

many other flyers buy 'dog spikes' that screw into the ground, and they are far stronger than straight pegs.
Jun 10, 2002, 08:04 AM
Experienced Member
Schluter60's Avatar

Common Sense Very Handy in RC Aircraft


Quote:
Originally posted by William A
Anybody else having bad visions of that anchoring stake loosening out of the ground and come shooting back at you like an arrow ?.
William,
Having the anchor stake flying back at you is a concern, but, common sense is very valuable in RC flight as in life itself. Check the condition of them soil and drive in an appropriate sized stake. Obviously, you wouldn't use a 3" stake in sandy soil or would you pound in a 24" stake into hard pan. I use a 12" stake into slightly moist clay type soil and I have to really pull on it to remove it when I am finished for the day. Home Depot has a good selection of stakes, your safety depends on your selection, a little larger stake is better for a larger margin of safety.
Jun 13, 2002, 10:47 AM
Crashez-vous sans stress!
Dan H.'s Avatar
Quote:
Originally posted by BioHazard
POP QUIZ... if it isn't ANODISE, what is the name of hardening steel ??
I think the word you may have been thinking of (but not the process) is annealing, which actually is a softening process for steel to allow it to be machined etc.
Jun 13, 2002, 12:41 PM
Lifes 2 short, go sloping
for saftey sake even though my ground is rock hard and I use a hammer to get in and bang it back and forth to get it out I use two. One is connected to the bungee and the other is tightly tied to the first stake 12" away as a backup and to distribute the load over both stakes, this might be an idea if your at all worried.


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