JETSETF18

How can I build my own Bungee launch system for my HET FA-18? If anyone has built their own bungee lauch?

Walt Thyng

My Feedback: (9)

Check the back issues of Quiet Flyer. I built one from their article, but I substituted PVC pipe for the wood. If you want I could probably get a photo or two of mine.
Walt

JETSETF18

Yes please, a couple of photos would be awesome. I wrecked one of my HET F-18s because I hand launched it. No more of that! I don't want to spend 100.00 for a bungee and a pedal though. I don't have back issues of that magazine.

Larry Dudeck

My Feedback: (1)

Here are a couple of pix of my ramp. It's made of scrap wood and some 3/4" foam pipe insulation. The pedal release was purchased somewhere or other. The cord is a Home Depot item.

For a size reference, the WS of my Fouga Magister is 56"

JETSETF18

wow, it is really short! What kind of cord you buy at Home Depot? I was just there and they don't have bungee cord. I found this really good site showing how to build a pretty good launcher. http://www.yourzagi.com/launcher/

CTulanko

I have pretty much tried em all...wood, ramp, rail ground drag, dolly...so far the Dolly Bungee Launcher is the best.

Here are some pics on building a wood launcher:

http://www.rocketryforum.com/ctulank...=bungee%2Fwood


A few more on building a pvc launcher from the your zagi plans:

http://www.rocketryforum.com/ctulank...r=bungee%2Fpvc


Some of the PVC assembly with the option of using padded rails or a ramp, depending on the model:

http://www.rocketryforum.com/ctulank...php?dir=bungee


A few of a better rail system with low drag (the last two pics):

http://www.rocketryforum.com/ctulank...f4dfirstlaunch


How to build a Dolly:

http://www.rocketryforum.com/ctulank...bungee%2Fdolly


The Dolly Assembly and how it works:

http://www.rocketryforum.com/ctulank...gee%2Fassembly


Note that I do not have any pics of building the pedal release, but it was easy with a cost of about $7 in parts. I used a 2' piece of 1 x 4 oak cut to 11" and 13", then bolted one of those door hinges that are sprung (2 in a pack for $4) with 6-32 nuts and bolts in the center of the top piece. I then drilled a 1/4" hole in the front bottom and cut the head off a bolt and installed it as a pin, then drilled a 1/2" holt in the top oak pedal. The rear was drilled and a piece of 1/8" nylon string and steel loop is added and a 12" nail with a fender washer anchors the pedal rear to the ground...real easy.

The reasons I like the Dolly bungee best are portability as I can keep everything in a small case, ease to set up, no large ramps or rails to haul, no wood setups to get wet (the bottom of the pedal was glazed with epoxy to seal it), and smooth ride the wheels give, buffering it from a ground ride. I have them all, used them all and they all got old, hauling them around all the time...now I only keep the dolly in the car. Let me know if you have any questions.

Carl

CTulanko

Here is a link to my HET/RC F-20 Tigershark video and we used a Dolly Bungee...the flybys were radar gunned at 109mph:

http://www.rocketryforum.com/reviews/carlshetrcf20.wmv


Another video of my FA-18 using the new oak pedal release we took a few weeks ago...this video is big, around 50mb because it is still in AVI format, but it is a good video of the Dolly launch system. I also use a rubber mat 30" wide by about 27' long as a portable runway, so that is what you are seeing in the pic...it sure smooths out those extra bumps in the ground:

http://www.scalerocketry.com/airplanes/MVI_0368.AVI

Carl

JETSETF18

Carl,
thank you for the awesome 101 on Bungee systems. Where do you think I could buy some of the tubing you have with the dolly setup? It looks like surgical tubing. I really wanted to buy it in my town somewhere instead of ordering it. Home depot does not have anything.

CTulanko

I did use surgical tubing and it has worked well over the years, but the new stuff is much better. I was able to buy mine locally at a shop, but I recommend you go to Aerofoam Radio Control and look at their Hosemonster Bungees on line for the best as this is what I am buying from now on. They sell the Black, UV protected Bungee, so it doesn't dry out from the sun like mine does and they have a great price. Look for the "Catapult" section a page or so down and this is the one you want to get:

Standard bungee 1/4"ID x 1/8" wall x 25' with connectors $45.00 (shipping included Con.US. email for shipping elsewhere.)

It comes with the rings already attached and ready to go and is good from 28-35lbs of pull...pleanty for Minifan models like the FA-18 or even Midifan models later. the URL is http://www.aerofoam.com ...anymore questions, just let me know.

Carl

JETSETF18

How about this Carl, its from areofoam as well. Its 40.00 and I guess its a new item good for EDF 1-5 lb models.
New: Zip Starts

Assembled Bungees for launching gliders and powered
planes in the 1lb. to 5lb. range. These are excellent for
launching E.D.F. jets.

15'-3m. rubber with 225lb. SS split rings, connectors and
25' of #18 fluorescent braided seine.
$40.00 including shipping in the U.S.

You supply suitable stake for your conditions, a 12" nail is good for hard
packed conditions, a spiral dog stake is required for softer soils or wet conditions.
Catapult launching has risk, it shouldn't be done around children or where people may
wander through. You must use a suitable stake, a pulled stake will be launched AT YOU!
You must use at least 25' of line, so the rubber and stake have to travel a greater
distance and lose speed before they hit you! 25ft. is a minimum.

CTulanko

That will not due...the hose is too short and too small...the 3M is only rated to a max of 14-18 lbs pull and that is not enough. Also, you need a longer bungee so you get a steadier, longer pull to get them airborne.

Carl

JETSETF18

ok, so I need what you originally said. Home Depot sells Latex hose, but it is only 3/8 OD with 1/4 ID and it is 1.50 a ft. Warbirds has a nice bungee cord for 56.00. What do you think of that one Carl. Looks loke it would last. It is made by RBC. Will

CTulanko

Home Depot stuff is no good...too small for use. Warbirds-RC bungee should work fine, but that is bungee cord and not bungee hose, so it works differently as it has different properties. Bungee hose like the Monsterhose continues to stretch while you pull it, while bungee cord will pull to a specific tension and hold until it is completely streched. Many people that are not used to using bungee cord will put it using a fish scale and stretch it out until they see their tension, but the cord will not be stretched enough. Bungee cord should pretty much be stetched until it stops, where as Bungee hose is stretched to a specific tension. It is your call on what you want to buy though. Also, remember that even though the RBC bungee is set up for ground drag, you can add the dolly to either setup.

Carl

JETSETF18

I think I will take your original advice and buy the 40.00 25' bungee from Aero. I had to email him today because I want to pay by paypal. So I will wait for Aero to get back to me on getting the 25' bungee with the ends installed already. Then I will wait some more for the bungee to arrive. My instant gratification is not working out to well today. I really wanted to go flying tomorrow. All good things come to those who wait I suppose. Wish we could go flying together. I use to live in Maremont, which is outside Cincinati--Will

CTulanko

Will,

Good choice bro...you will be very satisfied. I highly recommend you spend some of your "waiting" time and build that dolly and release pedal! If you have questions on the dolly or pedal, or if you need a list of the extra parts needed ask and I will help. Also, if you ever get back here, let me know; I would be happy to fly with you and we have some pretty darn good fields here.

Cya,

Carl

JETSETF18

Thanks Carl, once again you have come through for me with flying colors. Mark at Aerofoam got back to me already and is making my bungee up fo me. I agree with you on the dolly. It will prove to be the best for not only take offs but for transport as well. For now I'm going to try the PVC 5' ft long rail system. I had all those PVC pieces around the garage. I went to HD and bought a 1x4x6 for the pedal and foam for the rails. So that cost me about 8.00 dollars to build. With the new 45.00 bungee I should have a pretty good launch system for around 60.00 with spikes. Happy flying Carl!!!! Will

JETSETF18

Oh yea, where did you get the mat (runway) for the dolly system. 27' mat is really long. Other than that I should not have any problems building that. Will

Quandry

Sorry for the bump from the dead but I am looking for those plans to build the bungee dolly if anyone has them??