Bungee Launcher

Hi Everyone !

I am just starting out in electric foamy jets and shockies etc . . and have seen some excellent piccies of bungee launchers on th forums.

My problem is that I can't quite see how the release pedal mechanis operates ? ? ?

Can anyone out there please help this Modelling Dummy ? ! ? ! ?

I just want to be able to launch small heavy models safely when flyin solo at our local Club Patch which is too messy for decent take-off after our rainy season. ( Hand launching successful on lighte models.) This is only my second posting so I do hope I have'nt offended any o you folks through my lack of forum etiquette.

Your urgent help will be most gratefully received please folks ! :confused:

Regards . . . T B. United Lingdom

-- Thunder Barro

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Thunder Barrow
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I am not usre, but I THINK Sussex-models do a complete bungee launching system.

You don't NEED a pedal let-go..you can just stretch the rubber out hold the model and release..

Reply to
The Natural Philosopher

On Tue, 18 Dec 2007 04:19:39 -0600, Thunder Barrow wrote in :

Here's one:

Sequence from front to rear:

-- stake in ground

-- bungee

-- secondary string to aircraft which sits in cradle/ramp

-- primary string stretched to release mechanism, which is also staked down

The release mechanism is a pin that is retracted when you step on the release button. The button presses a lever under the release mechanism. The pin is part of the lever.

The primary string ends in a ring. All it does is sit over the pin. When the pin is pushed down, the ring is released, the bungee contracts, and the plane is hauled skyward.

The yellow flag near the release ring probably serves two purposes: easy to find the end of the bungee; drag from the flag probably helps keep from whacking the aircraft on release.

Here's a whole different system:

In this design, the release pin is in front of the aircraft.

The entire board rocks when stepped on to cause the tip of the board to rise over the pin and release the ring.

Marty

Reply to
Martin X. Moleski, SJ

Hi & thanks for your response !

Can't find anything on Google search in UK or S M C. I thought abou hand launching with simple bungee but wanted to take off S & L i possible - hence launcher. How do you work out or guess the righ tension for different model weights please ? Any help greatl appreciated.

Thanks & Regards . . . T B

-- Thunder Barro

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Thunder Barrow

On Tue, 18 Dec 2007 08:54:31 -0600, Thunder Barrow wrote in :

I think you learn by doing.

You may have to sacrifice a plane or two to get it right.

My guess is that you'll find it doesn't take a whole lot of tension to get a good launch.

Aim the plane level. It will tend to climb under acceleration. If you release with it pointed at a high angle of attack, you might cause it to stall. All you need to get from the bungee is enough airspeed to fly straight and level. After you get your hand back on the TX, you should be able to climb out under your own power.

Getting maximum altitude with gliders is a different story, of course--but I think this thread is about getting electrics up into the air.

Marty

Reply to
Martin X. Moleski, SJ

Thanks for your suggestions folks - and for the clarity in you

additional info Marty.

I could see the basic construction from the excellent piccies posted b Schluter60 but I couldn't work out the way the release mechanism wa triggered. Is there any safety catch fitted normally on thes launchers to prevent any mishaps when attaching the model for release If so how is it rigged please ?

The french set-up is very interesting Marty but I just want to be 110 safe as we do have public footpaths surrounding our flying field, an when on my own I can't afford to risk any harm to anyone naturally.

Thanks again for your input folks - T.B

-- Thunder Barro

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Thunder Barrow

On Tue, 18 Dec 2007 12:18:00 -0600, Thunder Barrow wrote in :

You're welcome.

If that's the PVC setup, the board that runs underneath is on a pivot.

Step on one end of the board.

The other end comes up.

The pin is under the other end.

As the other end comes up, the ring is lifted off the pin.

Here is a similar release device:

I don't see one.

You could, of course, put a piece of wood under the lever until you're ready to step on it.

I don't see anything unsafe about the French design.

It's pretty compact compared to the PVC contraption. It does require staking the bungee some distance from the takeoff spot whereas the PVC thing is self-contained.

Marty

Reply to
Martin X. Moleski, SJ

I've only seen one real bungee launcher in action. The part that was most interesting and effective was the TWO RING approach. One, as Marty has detailed, is affixed loosely to the plane. The other ring is dropped over the pin..under tension...and is released when the pin is retracted. Pretty slick, I thought. Rich

Reply to
rich

Thanks everyone for your rapid response and very useful information.

now have a clearer picture to build a unit which will hopefully fit th bill !

Just need to get some idea of required pull per different model weigh etc. . . so thanks again everyone. Great to get so much help s quickly ! I will post a progress report in a week or so after test which may or may not benefit others in a similar situation.

Best Regards to you all & Happy Flying ! ! ! Eddie. ( T.B. ) :cool: :

-- Thunder Barro

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Reply to
Thunder Barrow

I would say no more tension than the model weight. To start with anyway.

A failed bungee launch is just a long test glide anyway. If not enough tension.

If too much, it can be a wrecked model.

Reply to
The Natural Philosopher

You might try

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It's a good place to start, but may not have all the information you need. If I run across anything else, I'll post it.

Ron Kelley

Reply to
Ron

On Tue, 18 Dec 2007 21:41:15 -0800, Ron wrote in :

GREAT link.

Thanks!

Marty

Reply to
Martin X. Moleski, SJ

Only one word " springs " to mind ( ooooooooooooooooops ! ) -

BRILLIANT YOU GUYS ! THANKS AGAIN. Eddie ( Thunder Barrow )

-- Thunder Barro

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Thunder Barrow

Reply to
A.T.

Many thanks Alan for excellent variety of info ! Will have som

serious reading time before I decide on which method or system to use. :D :cool:

Best Regards . . . Eddie

-- Thunder Barro

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