Dr.Weasel

First off I want to thank you guys for helping me out. I now own an awesome 1/2a coroplast plane that will glide pretty good when i throw it but it doesn't have a line attached. That brings me to my problem. I'm only 14 and cant afford a bellcrank for about a week but i have been starved of flyt for about two weeks and cant stand it anymore.
Do you guys have any ideas on building a bellcrank?
Maybe out of coro. or simple house hold items. Please help me out.

Thanks
The Doc.

gcb

Some have used 1/20" aluminum or 1/8" plywood successfully. If you used either of these on your plane you probably have some left over. If you did not build your plane, I would suggest waiting until you can purchase a bellcrank and control horn.
DO NOT build one out of coroplast or any other light material. The bellcrank must support the pull of the airplane and occasionally, a sharp jerk on the lines.
If the plans do not show it, you should reinforce the area where the bellcrank will be mounted so the strength will be distributed over a wider area on the coroplast.
What plane did you build and how is the engine and control system mounted on it?

George

Dr.Weasel

My digital cameras batteries are dead so these are the plans i used (its a left
handed plane but i'm right handed so the bell crank will be on the other wing)
http://users3.ev1.net/%7Ecdjump/main...e/gallery.html
My plane:
The fuselage and the wings are made of 2mm coroplast
The firewall, elevator and rudder are made of 4mm
I used my cox .049 sure start. It doesn't have a built-in fuel tank so i bought
a (i think brodak) 2oz. tank that its in the front of the fuselage. Like in the picture i'm
going to put the bellcrank right under the inside wing.

When i build and install the bellcrank and control horn ( I think thats what its called, Its
the triangle piece that connects to the elevator) is there anything i need to know?

What does 1/2a size mean? I thought it meant 1/2 ounce weight of the plane but my plane weights a lot more than that.

Also how long should the line be from the plane to the handle for a 1/2a size plane?

Thanks
The Doc.

green river rc

My Feedback: (2)

I don't know the answers to all you questions so I'll let one of the real CL guys answer, but I will say, cant wait to see some pictures. I made a 1/2a CL plane once from a doped sheet of cardboard, probably simular to yours. My bell crank was made from 1/8" plywood and had a coat hanger for a push rod. I remember being very surprised how well it flew. I had 30' lines on mine, but not sure if it was the correct length or not. When I was a kid, a buddy of mine had a plane that he flew with a stick (right from the tree, bark and all) tied on the end of each line and he flew it with both hands, yes... a stick in each hand! It was funny!

RRyan

Doc,

1/2A refers to the engine size actually. Officially by the rules 1/2A is engine displacement up to .049 Cubic Inches. Your lines should be 25-30 feet long.

1/8 ply will make a useable bellcrank however, Email me your address and I'll send you one.

gcb

Doc,
The picture to the right of the plans on the web page you listed shows the control system. It appears to be made out of coroplast. Note the bellcrank and control horn (the part on the elevator. It also shows a reinforcement of coroplast between the wing and the bellcrank.
I would follow Randy's suggestion of 1/8" plywood, however. Although I have not yet used coroplast I would hesitate to use it for a control system. Then again, apparently it works.
If you search further on that site there may be instructions for the control system.
The plans indicated a 28" wingspan which appears a bit large for the Sure Start so I would keep the lines at 30' or less.
Good luck with it.

George

propjobbill

If you have access to a band saw and some old vinyl siding you can cut bell
-cranks from that. If any one is building or residing in the area they would probable be happy to give you a peace of cut off scrap. you can also cut it with a good pair of scissors, drill the holes and it will work fine for a 1/2a plane. I have built coroplast 1/2a planes I would suggest you double a piece of coroplast about 1" square and glue it to where you put the screw through the wing. Coroplast is really some tough stuff.
If you use something like a 4-40 or a 6-32 screw use washers on top and bottom screw it down tight with a lock washer and a nut. it will compress the coroplast but as I said it is tough it should hold up fine for an .049 engine
If you want to use coroplast for your bellcrank try gluing a washer to the coroplast where the line and push rod go through. and never worry about it tearing through the coroplast.
A good glue is epoxy, the best glue I have found for coroplact is polyurethane glue. put a little water where the glue goes to the coroplast. Water is needed for the glue to set good. One company that sells the glue calls it Guerrilla Glue. They say it's the strongest glue on earth. I can tell you when it is used right the plastic will tear before the glue will let go, and coroplast is really hard to tear.

Dr.Weasel

Alright heres my plane. Dont laugh! Its the first plane i have ever built and its NOT painted yet.
Check out the sweet airfoil and fuel gauge on the side profile.

The Doc.

green river rc

My Feedback: (2)

Not bad weasle! Let us know how it flys. I admire anyone that is willing to spend the time and effort to build an origional design.

telmore

You can make a bellcrank out of a 1.5" toy wheel:

http://www.the.elmores.btinternet.co.uk/scan0017.jpg

Lot's of useful stuff here:

http://www.iroquois.free-online.co.uk/control.htm

Tony