Septic_Shock

Well, just finished covering my LT-40, and now I'm installing the pushrods. I noticed that the pushrod leading to the elevator is a little stiff. It moves freely a smoothly, but it feels a little "tight" when moving back and forth through the guide tube. Now, I've never had any experience with servos, or R/C planes for that matter.

Are standard servos pretty powerful? Do I need to put somekind of lube on the pushrod? (Please, no KY jokes! lol)

Thanks!

figment

Get a tube of graphite from the pinewood derby section of your local craft store (hobby lobby is where I got mine).


Patrick

smokingcrater

i wouldn't worry about it, there is always some drag in a pushrod setup.

onlyb

When I built my LT-40 I don't remember it being stiff, but that was a while ago. Standard servos are more than enough for the LT-40. What engine are you using?

jetmech05

LOOK AT THE END OF THE PUSH ROD GUIDE AND ENSURE YOU DONT HAVE A SMALL BURR TO DE BURR TAKE A LARGE DRILL BIT AND JUST TURN IT WITH YOUR FINGERS (LIKE YOUR TRYING TO DRILL DOWN THE GUIDE) AFTER THAT ROLL A SMALL PIECE OF SAND PAPER AND JUST GO AROUND THE EDGE ON THE INSIDE. BABY POWDER IS A GOOD DRY LUBE ALSO.
LT-40 IS A GREAT CHOICE GOOD LUCK AND HAVE FUN

somegeek

My Feedback: (2)

Is the pushrod tube straight? Did you glue them up while the pushrods were in the pushrod tubes to keep them straight? The servos have a bit of torque so you should be good. Doesn't sound like you have a lot of friction.

Kind of a bit late to ask, but did you install guides on formers 3 & 4?



It helps prevent flex in the pushrod. If you glued it up solid at the front and back formers, flex should be minimum. If you experience mushy performance you can always install carbon fiber pushrods later on.

Good choice of a kit! [8D]

somegeek

bruce88123

Carbon is a bit of over-kill on a plane of this type IMO as a rule but can be used of course. As long as nothing is "snagging" and the servos and controls themselves operate smoothly when flexed, you should be fine. Naturally we can't tell from here just how much drag you are experiencing. Apply a little dry lube as it will reduce the current draw on the batteries slightly.

Septic_Shock

Thanks for the info!
I think there may be a small burr where the push rod exits the fuse (where you had to sand it down flush with the fuse). I will try to clean it up a bit.

I did install a a guide at former #4, and they are solid at the front and back.

I did not glue the guides with the push rods in. Was this in the instructions? Or is this one of those bit's o' wisdom that everyone here seems to be overflowing with?

Oh, and to answer onlyb's question, I've got an OS .46AX ready for this puppy! Can't wait.

Thanks

somegeek

My Feedback: (2)

right on.

Didn't read that in the instructions that I remember... Just figured the pushrod tube held more straight by the pushrod helped me align the two extra guides pretty well for a straight path. After everything dried I could tip the plane up and the pushrods would fall/slide out of the tubes on their own. Guess that meant the tubes are straight.

That engine rips! Least as far as I can tell with my limited knowledge.

Got any pics of your build to share? Cool to see pics of other folks LT-40s. [sm=thumbup.gif]

somegeek

Septic_Shock

The pushrods fell out? Oh crap, mine or not near that loose, even after de-burring. I think that when I glued them in, they may have sagged in small amount.

Okay, so new question....Should I wait until I get the servos in and see if they can push the elevator/rudder with ease. Or, should I try to debond the glue and pull them up tight and reglue while I don't have the tail-feathers on. (This would involve some cutting of the monokote and subsequent patching of the cover. If this is the case, then how do I debond epoxy?

On a lighter note, I will be posting finished pics. I really like the color scheme so far: Yellow wings and tail feathers with a royal blue fuse. I think I will also be checkering the underside of the wings for contrast. Also, the joker in me is tempted to print out a vinyl sticker for the front windshield depicting the cockpit scene with Major "King" Kong in the bomber from "Dr. Strangelove"

Septic_Shock

Okay, after a lot more reaming with the drill and a little foot powder, I've got the pushrods movin' ah, so sweet. Thanks for the advice, guys! Like I said, I'll be posting some pics as soon as they are available.

bye!

horace315

My Feedback: (15)

i would polish the push rod also with some 220 or higher,i have also made bushings out of the yellow inner push rod material from dubro kits just cut a few pieces about half inch and slide it on the metal rod,they have about 4 contact points on them so not so much material to cause drag.hope this helps...happy flying

laker500

My Feedback: (2)

Better then the mees from dry graphite is to use paste car wax. Put a couple heavy coats on the inner rods before you install them. Don't wipe it off once dry and it will last almost forever. There is no mess and it doesnt atract dust like a liquid oil product will. Jeff