mikenlapaz

Mid Star 40
1" tapered aileron (thick to thin .235" to .080");
torque rods .094 diameter and overall length into aileron ( .685"):
drilled hole with a piece of sharpened brass tubing and was not true vertical in drill press, and side of aileron got drilled out.
At the tip there is a whooping .036" of aileron to hide BOTH sides of the torque rod!

I'm somewhat commited to using the torque rods on this, my first kit build.

How do you install torque rods without this problem? I'm limited to some 1/16" stock that is long enough (29.5") . Current thoughts are to
either try to glass the aileron at the torque rod insert or possibly glue on some 1/16" stock to both sides of the ron and plane it down to a thicker taper.

Or some 1.5" ron stock and wait weeks for it to arrive at this desert island! http://www3.towerhobbies.com/cgi-bin...?&I=LXJD20&P=7

Need some advise.

SPLIT S

Drill the holes for the torque rod by hand - skip the drill press. Things happen too fast with such a tool to keep complete control. If you haven't cut the hinge slots yet I would just switch ailerons from left to right. Patch the drill through with some scrap wood, epoxy or something similar and try again using the other end of the aileron. I guess that even if you have cut the slots you can carefully fill them in and re-cut the slots in their new positions. Remember, sometimes slow and steady wins the race.

Good luck,
Dan

R8893

My Feedback: (20)

I agree with what Dan said. I do one extra thing. I hold the flat side of the aileron between my thumb and forefinger right where I will be drilling and I can feel if the bit is getting closer to one side than the other. I then force it back toward the other edge. The hole may be somewhat sloppy, but some extra epoxy when installing the torque rod will fill the hole. Fortunately the OSHA inspector is not at my house to cite me for such an unsafe act, but with the drill running slowly, I have yet to injure my fingers.
Chuck

safeTwire

My Feedback: (2)

Heres a possible fix:
Brass tube to fit over rod, notch aileron snugly to brass tube, sandwich brass tube onto aileron with thin ply doublers top & bottom . (Optional stitch)

MinnFlyer

My Feedback: (4)

Split S and R8893 took the words right out of my mouth.

Just patch the holes with filler and sand smooth, then re-drill the holes on the other side like R8893 said - by holding it between your finders so you can feel if the drill is starting to bulge one side more than the other.

One other helpful hint: Grind the ends of the torque rod down so they resemble a screwdriver tip. That way there's less chance they will poke through

mikenlapaz

What do you use for a 'hole-maker' twist drill or tubing? Personally drilling straight holes has never been my strong suit.

"At the tip there is a whooping .036" of aileron to hide BOTH sides of the torque rod!" 1/3rd of the thickness of a business card.


I chopped off a section past the wing tip and used it as a support side to the area where I drilled the first hole. In a few minutes, I'll go check and see just how much length is left.

"Patch" is starting to look like a good nickname. the drilled hole is such that the torque rod or the brass tubing inserted is still within the torque rod but the soft wood distorted to were the metal is clearly visible and the strength of the hole is in question. (If the hole were filled with a liquid it would run through freely.

Just looked and there is sufficient ron length to turn end for end, and just clear the location for the outer CA hinge location.

Tissan

this thing witht the torque rods happend to me on my first mid star so i bought wider ailerons and installed them and kept the throw as the manual said, it flew fine, better the my current mid star.

second thing you can do is to switch side, shorten the rods and drill it by hand, also see what i did in post #120
http://www.rcuniverse.com/forum/m_65..._5/key_/tm.htm

Alex

MinnFlyer

My Feedback: (4)

I use an electric hand drill

mikenlapaz

Composite fix:
1) Grind down, taper the last 25% of torque rod. to screwdriver shape;
2) When installed, after hinging (but before CA the hinges) do the 'glue and stitch' with some epoxy (Oh good, a chance to do some small stuff with a needle, I can probably get some blood into this project yet!)

Picture to follow.

It sounds like twist drill is the preferred 'hole-maker' for this project.

safeTwire : I'm not following how I would use a brass tube on the portion of torque rod before the 90 degree bend?

I like your idea of the wood doublers. It would be quicker lighter and easier than trying to put fiberglass tape the area.

mikenlapaz

Surprized that I could not find more data in 'Search - Torque rods'. I thought a twist drill would be more difficult to use in thin soft wood than a section of sharpened tubing.

safeTwire

My Feedback: (2)

The brass tube would slide over only the straight part/end of the torque tube which enters into the aileron itself.

Actually, the brass tubing is not really necessary, I apologize and should have thought it further through. In case you needed to "make up" space where you accidentally removed material from the aileron, the brass tube can be fitted like an insert.

Basically, if you re-drill the original hole straight, even though the torque tube might/will be loose in the aileron due to extra material removed during your first drilling...rough up the torque tube well with coarse sandpaper, mix 30 minute epoxy, make your thin ply sandwich pieces plenty wide for good bearing surface, line it up, clamp it, and you should be good to go. Wait at least 24 hrs before you fly

mikenlapaz

There have been several comments about oversizing the hole and filling with epoxy. For strength, do you really need this added clearance and epoxy?

I'm thinking that a tapered rod, roughened and placed in a wetted out hole and groove would be good to go.
On the pictured aileron, an inch or so of doubler, even a section of 1/16" balsa would be okay.

How much of a problem is this area once the plane goes into service? If I wanted this ailron to safely handle 42 oz of torque, how would I prep and install a torque rod?
I realize the load is somewhat determined by the size (area) of ron and the torque rating of the servo.

SPLIT S

I've never in all the years I've flown seen a torque rod "fail" by pulling through an aileron. ( Excepting the occasional unscheduled landing )Once the rod end is epoxied into place in the aileron they move as one unit. I wouldn't be concerned about the extreme end of the rod being so close to the upper and lower surface of the aileron. The widest part of the aileron is almost 1/4", the rod end is being well supported for the bulk of it's length. ( as it protrudes into the aileron ) I think if I understand you correctly your fear is that the end of the rod would somehow poke it's way through the surface of the aileron. This could only happen if there was rotation of the torque rod end in the aileron. This can't happen if the rod end is securely epoxied in the aileron. This is a excellent 40 size plane but it won't be traveling at extreme speed, so the load ( resistance that the aileron servo has to overcome ) is relatively moderate compared to other speed demon, huge control surface types. Your hinging and gap have way more affect on aileron function ( or failure ). Re-drill the holes, a little oversize is ok, clean the rod end and epoxy it in there. Then get out there and enjoy your handiwork....

Have fun,
Dan