Phred's way control systems

I actually saw a flat plane horizontal C/L bell crank linked to drive a 90 degree vertical second bell crank that was cable lashed to top and bottom horns on a elevator.... from what I saw a precise setup BUT IMO just and exercise is fabricating with little gain in actual needed control responsiveness

Most current state of the art push pull (control rod) systems can be really free moving with very little measurable slop using good hinges, horns and ball links

and there is a camp that suggest a little slop in the flap or elevator is a good thing to dampen "Hunting"

I also saw in the RC club some guys with BIG 3D planes that needed 2 or more ganged servos in Pull Pull to have the ass (torque) to move the big rudder or elevator

Upper left is typical kit supplied music wire, a length of small diameter carbon tube and two brass ends the fit OD of the CF tube

I cut the BC side of wire to have enough length to fit 1.5" inside the tube and still have full clearance on the BC. The aft end to the Horn is also cut for 1.5" inside the tube. I only J&B glue in the aft once I set and hold Neutral elevator. Lighter and no flex than just the plain music wire

Very bottom is the large diameter Arrow shaft CF tube I used on the Ring Master. I really do not like the thick diameter look but it is still light.

In this case, I used a wood dowel inside the tube drilled to accept a length of 4-40 all thread at the aft, and 5/32 Music wire with "Z" bend to the BC. The various pieces of Brass or aluminum tube you see are for the outside of each end of the CF tube to prevent breakout. Some folks just CA and thread wrapped on the end to prevent any splitting



There are all sorts of pre made ends you can buy...some insert into the correct tube diameter and others slip over the outside

Mine are from Central Hobbies with a size I like for my preferred smaller diameter CF Tube. They are Titanium with 4-40 thread on the end and there are some folks who claim the machining of the Titanium bakes it brittle and stress breakage prone.... I do not fly enough to have had a failure ---yet





I prefer J&B cuz it is easy to mix up the very small amount needed and stays where you put it. But 30 min epoxy (I think with some thickener like Micro balloons) will work. I know a guy who does all his with Thick CA
Prep is the key, light sanding for all the glued surfaces, and a good cleaning to remove finger oils. I use Acetone but 91% Alcohol will work

Another plus is the system holds paint a lot better than the music wire in case you do not want the black tube look

Pretty slick man! It's good to see and have explained how "you" do it. I've made some small pushrods from .060" CF rod.. but haven't put them into service yet. I went the thick CA route for the links.



The sleeves are aluminum tube (.062" ID) and the Z-bent links are .062" music-wire. I filed some light notches in the music-wire ends, to be inserted into the sleeves beforehand.. and also roughed them up with coarse abrasive. The sleeves are only .5" long though.. so there's only .25" of retention for the MW and the CF rod.. Strong enough? Only God knows. It's said that CA glue lacks strength in the "shear-plane" which concerns me. There wasn't much I could do to "rough-up" the insides of the sleeves for glue-retention, their being of such a small inner-diameter. They're very lightweight though..

Here's the weight in grams, of "one" length of .062" music-wire..



And here's the weight in grams, of "two lengths" CF rod with links installed on one end..



Interesting isn't it? I have to wonder how much lighter a single CF rod is.. than a single MW rod of the same length? This would make quite a difference on a small model. My "Phred's Phault" 1/2-scale VooDoo has been eating at me lately to finish the damned thing.. A CF pushrod would actually be easier to install.. than my usual method.