Ribs etc.
Ribs etc.
A couple of questions?? The gyro in the picture has an elevator. Are you planning to have both elevator and tilting in pitch contorl or just elevator?
I am building a Ron Heron Little Wing T tail for a bensen. I have the polyfiber manual and video on covering. The problem I have is the instruction material talkes about what to do when the rib are flat but not what to do when you have round tube as ribs. Ie. how far apart are the lacing holes? And if the ribs are smaller than the outer frame what do you do? My current plan is to use poly fill to glue some wood cap strips on the round tubing and fair it to the shape between the front and rear tubes on each sturcture ie vert stab, & rudder,. The Horiz stab is all one size so I am wondering how to lace the "ribs" on it with the round tubes. Any one have any experience in this??
Please look at our earlier shots on the other string. There you can see how I glued (with Gorilla glue), wood ribs onto the top and bottom edges of the square steel ribs running from fore to aft on the leading and trailing edges of the horizontal stabilizers and on the rudder.
There is a formula to develope the proper air foil curve to the added wood strip. It is (check your plans) 25% of the length infrom the front edge, 10 to 15 percent of the length from the front edge to the back edge in height of the curve. . I made a paper template to develope the curve, and to match the curve it would be glued to first.
(You can see some of these templates and the curves plainly in our other posts). You will need French curves to lay out your template before cutting the wood out. This information is very tiny and printed on one of the sheets. You will need a magnification glass to be able to read it. If you can't find it, we can look up the page for you.
There are no ribs on the plans for the rudder, so these were made up of fir and added to the rudder. This provides a secure place for one to attach the cloth with the stitching process.
The rib stitching is approximately 3 inches apart. I made a needle of a welding rod. Heated the head end and flattened it out, then cut a hole in it for the thread with a small cut off wheel in a moto-tool. Grind a long point on the other end. Use a small welding rod to keep the hole size down. Round and smooth everything good to keep any burrs from tearing the cloth.
Measure down the rib and make a dot with a felt marker on both sides of the rib, then do the same thing on the other side. Pierce the cloth with the needle, and line the point up with the dot on the other side, then pierce the backside, cross the rib with the thread, and return to the first side with the same process.
Wicks can supply you with data on ribstitching technique, or you might want to talk to one of your friends, as to how to tie the not, when moving from stitch to stitch. Its fun and easy, but takes a little time to get the technique right. It is one piece of thread from the first stitch to the last one on each rib.
You will place a protective felt strip, which is self adhesive from wicks about a quarter inch wide, over the outside of the cloth which has already been shrunk and doped, before you begin the process. Then you will follow it with a covering tape, which will reinforce the area, again doping it also, sealing it in place. The tape covers the stitching and seals and waterproofs it inside protecting the holes you have made where you pierced the cloth covering.
Remember you only glue the outside edges, so that the colth can shrink up over the ribs and move while doing this before you do the rib stitching. Do not glue the cloth to the ribs.
I am using my elevators for trim only, since I have a fully tilting rotorhead.
:first: Hope this helps. Booster Rich.
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