catboater

My Feedback: (51)

I was given an old 1/5th scale Pica Spitfire which I decided to replace all the servos in. I tied a string to the wire and pulled the left side but while doing the right side I dropped the new servo and the string came out of the wing. !@#$%^&*!!!
Attaching a weight to some small diameter line and shaking the wing to find the holes just isn't working. The holes the builder threaded the wire through are barely big enough for the servo plugs. Add to that, it isn't a straight shot to the center of the wing. It bends around the wheel well.
Do any of you have a magic bullet to fix this? The last hour of dicking with this has driven me crazy with nothing to show for it.

Scar

My Feedback: (3)

Simple. Take a deep breath.

Now, stand the wing on end. Slip a thread (not a string, a thread) into the center hole. Place the tip of your shopvac nozzle in the servo hole. Feed the thread in as it advances.

When the thread's through the channels, pull a string. Or just pull the servo. Repeat on the other side.


Best wishes,
Dave Olson

airbusdrvr

I saw at Home Depot a flexible inspection scope with an external viewing screen. Maybe find a laproscopic surgeon to loan you laproscope You do have a delimna.

airbusdrvr

Now that is clever and it could work. What about a small wad of paper(approx 1/4" size) tied to the end of the string to give the air something to exert a little more force on pulling the string?

Scar

My Feedback: (3)

It does work, no need for a paperwad or anything. Try it.

Good luck,
Dave Olson

eagle1945

glue a Q-tip head to the thread, it should be smaller than a servo plug.

badger5964

My Feedback: (6)

I have a length of the ball pull chain, like used on overhead light switches. THe flexibility of the stuff is super, its weight helps it through the slots and the balls roll around objects without cutting through. Just stand the peice vertical, drop the chain through the top hole, wiggle and shake the peice to get the chain to drop through. For tight pulls I'll thick CA the chain to the extension plug. The CA does not stick hard to the plug plastic. Then just pull the chain and the servo wire with it.

I own a crimper to make my own extensions and the like. A really tight fit could be done as above and add the plug when the pull is complete.

Good luck

Scott

catboater

My Feedback: (51)

Scar, Great idea in theory, but the thread gets sucked part way in, then balls up and doesn't make it to the exit hole. It would work great with a straight pull and it did make for some great father-son time. My son sealed the wheel well and servo bay with masking tape and then cut a hole to fit the vac nozzle. The thread was sucked right in but our euphoria was short lived with no thread in the exit hole.
I'll try the Q-Tip idea next and then the pull chain. They are all great ideas and would work on a more modern wing design. I don't know if the original builder cut the holes so small or if it's a Pica design but it's really tight in there.
I really screwed myself with this one!
I'll keep trying and report back the results.

Scar

My Feedback: (3)

I understand, but the technique works even with staggered holes.

You hold the thread, and feel for the "pull". If the thread isn't pulling on your fingers, it's caught on something. When that happens, you pull back a bit, until you feel the thread "pulling" again. When it's ready to go through the hole, it will go, and you'll feel it in the thread. It might take 20 times to get through a particular hole, but it will go.

You might reduce the suction, turbulance could be making the thread whip around all over. (more chances to stick some place.) Try opening holes in the masking tape. You can always put a finger over the hole to vary the vacuum.

By the way, I completely understand and sympathize. I was in precisely the same situation you are, this is what worked.

Good luck,
Dave Olson

Rodney

Bager's method, post #7 above, works very well, even on staggered holes; much easier than vacuum and string.

safeTwire

My Feedback: (2)

I use a small lead split-shot used for fishing. Crimp it on a string, and it will find it's way out of anything. They come as small as a BB, and are re-usable.

Steve Percifield

My Feedback: (14)

The ball chain is the way to go. Buy the most flexible you can find. It will find it's own way through the holes, even staggered. It's a life saver.

tacx

My Feedback: (1)

Scar has it right. The meathod works. Being an electrician for 32 years I have used it many times. Don't put anything on the end. The thread will find its way. A WORD OF PRECAUTION: BE CAREFUL HOW MUCH SUCTION YOU PUT INTO THAT WING!! A large vac could collapse the wing. Take it slow.

42etus

My Feedback: (2)

Use caution with this method. I tried it several years ago and actually crushed the wing by using too much suction. I'm not saying it won't work, it does, just use caution.

Mustang1971

My Feedback: (30)

I use magic.......


seriously though, I use a piece of music wire (like 14-15 gage or 1/16" or so) with a little bend in the last inch of one end. Start feeding the bent end into the wing and twist the wire to "steer" the bent tip as you feed it in

catboater

My Feedback: (51)

I am happy to report that we got the servo lead pulled using the pull chain technique. It took awhile and 3 different guys trying but we finally got it through.
We tried all the suggestions you submitted and they were all good ideas that I'll keep banked in my brain for the next time this happens.
Thanks again guys!
Chris