|Apr 05, 2006, 07:14 PM|
Where's the elevator servo in a Jack built 60" LEG Reno Racer?
As the title says.. I need to know where the elevator servo is buried.
I bought the plane used, but know it was originally built by Jack and I
assume he puts the servo in a fairly consistent place so I'm posting here
in case someone else knows.
My Reno racer got flushed (I mean like 1000 feet per minute sink)
to the bottom of Zion a few days ago, and it landed on the nose
pretty hard and broke the elevator servo arm off.
|Apr 05, 2006, 07:30 PM|
Pretty much right about here.
You could always use a sharp needle and push it in to make sure..
Re looked at the picture prolly a tad more back give or take.
|Apr 05, 2006, 07:59 PM|
Arm is on top. The servo is set off to the side so that the clevice is on center. Must have gone down HARD! its a digital 5475HB in there.
|Apr 05, 2006, 08:39 PM|
When I crashed my cobra hard a couple times the nose bent so much that the elevator pushrod would crease/break right where it goes into the carbon tube near the servo. My last big DS crash did that AND broke the main gear in the servo... 325HB. If you just broke the horn you're lucky!
|Apr 05, 2006, 09:53 PM|
anything at the elevator end.
And yes, it went in pretty hard. One moment I was standing on the top of
Zion flying some big air and next it got flushed about 500 feet down in
a matter of seconds (kid you not, it was on a glide slope steeper than
45 degrees). Decided I'd make a run for it and try to land it on the far
side of the canyon. Mountain sized rotor got ahold of it and after a couple
unintended flips and rolls, I lost sight of it about 1500 feet away
for a second, and the next I saw it tumbling. Nose is all scraped up
and somewhat accordianed and elevator is disconnected somewhere.
I'm surprised it isn't broken more. The horizontal stab has broken
on both sides of the fuse 4 times so far, but didn't break this time.
|Apr 05, 2006, 10:10 PM|
Master of the obvious
|Apr 06, 2006, 12:23 PM|
Well, turns out, as suggested above, it broke the plastic pushrod
just beyond the end of the threaded rod that the clevis attaches to
on the elevator servo end.
I think at least one other person here in Colorado had a similar problem.
Too bad it wasn't a broken servo arm, because this is going to require
major surgery just to get to. BTW, one way to prevent this sort of
thing (we've seen it a lot on combat wings with Goldenrods), is to use
a conventional metal pushrod that's mostly smooth and then threaded at
the end. Cut it down to say 3-4 inches in length, then push the smooth
end into the plastic rod (it's slightly smaller diameter than the threads so it
slides in freely), then then screw the threads halfway into the plastic
normally and attach clevis to the remaining threads.
That way the smooth part of the metal rod reinforces the plastic
rod for a couple inches as it goes well into the pushrod housing, so it
can't kink and break.
|Apr 06, 2006, 12:41 PM|
Very good idea! I will do that next time it's in for surgery although this last big DS crash took out the servo gears too so it wouldn't have completely saved me.
|Apr 06, 2006, 01:01 PM|
Joined Jan 2005
It sounds like you may be able to do a bit of proctology combined with a hole through to the servo arm area and git her fixed up without too much surgery. But I think it's gonna leave a scar.
|Apr 06, 2006, 04:04 PM|
Well, the problem was the plastic pushrod was now shortened due to
the break, and there's not enough threads on the end of a standard
metal pushrod to do the trick described above.
So I went ahead and pulled the plastic pushrod out the tail,
knowing it was going to be a pain in the butt to put back in
and not having any idea how I'd do it.
I found I had a package with DuBro Laser Rods that has the same
diameter inner plastic pushrod, and what should I find
in the little packet of hardware, but four 4" long standard metal
pushrods (4 inch rod with 3/4" of thread on the end), made specifically for
this "trick". I cut plastic pushrod to the same length as the
original in the LEG (with broken bit added back on). Then
attached the two 4" metal rods at either end (giving over
3 inches of stiffening at the ends).
Then I screwed a clevis all the way down tight at the tail end
and reinserted the rod back into its housing (not without some pain
there since I couldn't see the end of the tube, and was
accessing it from a hole in the side of the tail at an angle.
Anyway.. now the pushrod is almost back in place, but I needed
to get the clevis back on the front end while working through a
small little rectangular opening.
Had a brain storm.. Pulled the tail end back out a little bit,
strung a string throught the clevis prongs and then wrapped it around
the end of the clevis about 20 times clockwise. Stuffed it back into
the hole in the tail. Grabbed the front clevis with a pair of needlenose
and held it lightly against the visibile threads on the front end of
the pushrod.. Then just pulled on the string.. which spun the pushrod
20 times, and *zip*, the front clevis was screwed right on.
Reattach to control horn and servo arm. Done..
Just need to fill up the whole holes I made, clean up the fuse
and it should be ready to fly again. It's no longer a really pretty
plane (which is really too bad, because it was a real beauty) but
it'll still fly decently.
|Apr 06, 2006, 05:07 PM|
road trip tomorrow. Driving down to SoCal over the weekend
for a huge R32 GTG and track day at Willow Springs - Streets of Willow.
Probably won't even have room in the car for more than one or two
planes and no time to go flying there before I have to come back.. ;(
|Apr 06, 2006, 05:22 PM|
Joined Jan 2005
Hey, that's fun too. No one should limit themselves to only one hobby.
Good luck at Track Day.
My weekend flying will be very short, if at all, as I've got lots of work to do at the greenhouse and I need to start prepping one of the boats for this summers sailing season. Not to mention de-winterizing the motorcycles, tuning/repairing the tractor, etc. Somewhere in there I've got a P-51 and now a Jart to build too.
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