Jump to content

Bungee launches on the slope anyone?


Ned
 Share

Recommended Posts

Does anyone have any knowledge or experience of launching larger gliders (2.5-4m) from the slope using a bungee and a launch rail? I’ve had a look at several YouTube videos although they were nearly all from the flat and some of the devices were impressively complicated. I also found videos where the launch just used a standard bungee and the model was pulled back by the launcher, bounced a couple of times and released on the up bounce, both on slope and flat.
However I’m thinking that the rough slopes we fly from will require some sort of launch rail to lift the model above the clumps and provide a smooth launch surface. I’m also looking for solo operation so some sort of restraint operated by a foot pedal will be needed. Of course it has to be extremely light as it might have to be carried some distance to the slope and also small enough to fit in the van!
I’ve had a few ideas using poly pipe but would be very interested to see any successful gadgets already in use. 

Link to comment
Share on other sites

Seen it done a few times, launching off the floor, with a foot release.

Launching into a wind meant the gliders became airborne almost immediately and at very low ground speed.

Not dramatic at all. 

Slope was bumpy but model was high wing and had a wheel. Once off the ground the bungee was more like a kite string.

Link to comment
Share on other sites

oipigface

I half-heartedly looked into this a couple of years ago having seen several clips of Italian guys launching from rails. There's a guy called Mark Mech will sell you a readymade system for a not inconsiderable price. Let me know how you get on especially if you find any kind of details of the construction.

Mark Mech
Aerofoam UAV Systems
www.aerofoam.com
360-927-2546

Link to comment
Share on other sites

Thanks for that. I've had a look and they seem really sophisticated, far too complex to drag up a heather covered hillside! They must be Rolls Royce prices too as you have to ask, they don't publish them. 😆

I've been to B&Q today to have a look at their plumbing supplies and they have 40mm plastic pipe and fittings that are cheap.Cheap enough to try a prototype anyway.

 

Link to comment
Share on other sites

Woodstock

I tried a lot of different things with bungees on slopes.  The "bounce" method (as is common in the Alps, etc.) is really the only one that works on slopes that are not dead flat IMHO. I still have this foot pedal release I made (as well as a huge quantity of Hosemonster premium rubber tubing, fittings etc.). I was trying to launch a fairly heavy model. It didn't work due to friction with grass / low brush slowing the model right down and preventing it rotating. Best to hold it in one hand, walk back to stretch rubber, bounce and release.

Chris 

Bungee release foot pedal.JPG

Link to comment
Share on other sites

Graham Woods

Bro David (f3fisa) used a homemade 'rocker device' similar to the one in the picture a decade ago. As I remember, little stretch was required on the slope as you can see and the launches were easy. Needless to say the model really needs a wheel. I did a video at the time.  gw

 

 

Link to comment
Share on other sites

Thanks Graham, that video is very interesting, not least because it’s exactly the same model as I’m trying to launch! 
The other problem is that very few of our slopes are smooth enough to use the wheel and most of my models don’t have one anyway hence investigating a launch rail system.

 

B3C3C8A6-0C86-482F-A347-BA86B8CC8556.thumb.jpeg.c281177b29d1b349d81fbf1c22d29779.jpeg

Link to comment
Share on other sites

17 hours ago, Woodstock said:

Best to hold it in one hand, walk back to stretch rubber, bounce and release.

Thanks Woodstock, but that’s the bit I’m having trouble with 😆. My Fox fuselage is quite fat and also slippery so difficult to hold onto. Not too bad in the summer but in winter, with gloves, I’ve found it impossible to get a secure grip, especially if the wind is a bit gusty, which is why I’m investigating a solo launch technique where I don’t have to hold it.

Link to comment
Share on other sites

Woodstock
On 10/02/2021 at 13:44, Ned said:

Thanks Woodstock, but that’s the bit I’m having trouble with 😆. My Fox fuselage is quite fat and also slippery so difficult to hold onto. Not too bad in the summer but in winter, with gloves, I’ve found it impossible to get a secure grip, especially if the wind is a bit gusty, which is why I’m investigating a solo launch technique where I don’t have to hold it.

It's no doubt doable, but I think your'e into the realm of close-to-military UAV launch systems..

Link to comment
Share on other sites

My mate used to put his tx on the ground to launch his scale model, a little scary but he never crashed it

 

Link to comment
Share on other sites

eric friend

Hi Ned, Yes I've looking at the bungee launch issue as my team of launchers for my Purbeck Models 5.2 m MDM-1 Fox are getting older and weaker and I fear for their health! 😢

As the Fox handily has a built in wheel, I was going to use two or three lengths of 3" guttering pinned to the ground to make a smooth take off run with the motive power being provided by a 'v' of bungee held by two fellow flyers.

Well that's the theory!

However it does seem to work as shown in a video shot by one of my fellow flyers many years ago. They had one abortive attempt at 58s, but a bit more stretch at 2m and the Pilatus was away. All it needs is to get above flying speed and the model is flying even though it is only a few inches off the ground.

 

Link to comment
Share on other sites

  • 2 weeks later...

That was interesting, I enjoyed the video.

I hadn’t thought of the guttering idea, that might be the simplest method for gliders with a wheel. A cheap way of trying it out anyway. Thanks.

Link to comment
Share on other sites

  • 1 month later...
Baldrick

Hi there, if you can launch it ok on your own without gloves on,  have you thought of using a transmitter mitt, so you can fly without gloves, they help to keep the wind off your hands and if you need to keep your Hands warmer use one of those back pain heat plasters stuck to the inside of the mitt?

I have also used neoprene fisherman’s gloves with some success as they are “stickier “ than fabrics gloves + you can fold the index finger and thumb tips back for better feel on the tax sticks. 

 I used to struggle on windy days launching on my own, having to hold support the fuselage in one hand and steadying the wing with the other... after giving the glider a good heave it was then a race to get hands back onto the transmitter which invariably had rolled over out of position because of the centre neck strap, I cured this by getting 2 arms to screw to my tx and one of those “Bra strap” 2 clip harnesses, now I can reliably find both tx sticks after launch everY time

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.