Viper1GJ

My Feedback: (20)

I thought about that but that would make the other one too short. The right side is about 4mm short but that could be adjusted by the ball joint adjustment. I'll probably just cut both of them, get them both the right length again and then cover the cut with the 10mm CF tubing. The 10mm tube would butt up to the aluminum cap which is also 10mm in diameter so it would look ok at the cap. I would run the outer 10mm CF tube back about 6 inches on both sides and it would look the same plus it would give plenty of surface area to glue the tubes together and I could re pin them on either side of the cut. Thanks for the suggestion.

rfbenn

Viper if you can get the cross pins out I have successfully removed these rod ends by heating them up with a heat gun, it softens the epoxy up ,the first end will usually pop off as the air inside expands.

Custmachr

My Feedback: (3)

what if you turn servo 180 degrees?

dwr302

My Feedback: (2)

Yup, that does work.

Viper1GJ

My Feedback: (20)

Thanks for the heating ideas. I was just trying to fix it with the supplies I have on hand. I don't have any more rod ends here and I don't want to mess up the rod ends trying to get the pin out. It would probably mess up the CF tubes by heating and I don't have any more of those here with out reordering.. The pins were CA glued in before peening the end flat so they're really in there. Maybe soaking in acetone would free them after the pin end was ground off. I think the cut and splice method would be easier to get the correct length accurate rather than removing the rod ends. At least I have some 10mm CF tube here that I could slide over the splice and epoxy it all together. Still pondering the best fix with out getting all new parts. I think my end joints are good so I could still use them on both push rods also. Still a few days before I get any more shop time so suggestions welcome.

Thanks again.
Gary

Pondus

My Feedback: (1)

If you are 10mm off swap the servo around 180° that will fix the issue. No need to hack up the pushrod.

skunkwurk

My Feedback: (18)

I'm pretty sure he's already considered that idea. I bet he is trying to keep both sides symmetrical and with equal geometry. Symmetry is one of my (OCD) obsessions.

mr_matt

My Feedback: (10)

delete

grbaker

My Feedback: (29)

Me too.

Pondus

My Feedback: (1)

Understood, but as long as the servo arms and the stabilizer arms are the same, and the angles of both on both sides are the same a slight difference in the actual pushrod length makes absolutely no difference. I'd leave it alone, to much work to fix what is a non-issue really, my opinion of course.

yeahbaby

My Feedback: (21)

Or just order new pushrods and start over. What’s another week or 2 or 3 after what a year or so?

fotis kalevras

wow fantastic work!

kevinthoele

My Feedback: (1)

Just flip servo around and modify the servo tray as needed

Viper1GJ

My Feedback: (20)

That's exactly it since one pushrod is longer than the other. If my fix is not satisfactory, I will just order new stuff and start over. I'm still a few days from shop time again. I will post photos of the fix when I get back to it and see which way to go then. Thanks to all for suggestions.
Gary

invertmast

My Feedback: (23)

gary,
just incase it hasnt been suggested, just flip the servo around. LOL

Viper1GJ

My Feedback: (20)

Lol, I never thought of that before! In reality it would probably have worked if I had been smart enough to make BOTH pushrods too long. Alas, I was stupid and made just ONE of them too long so that's the problem. Shop time available later this week. We'll see then.
​​​​​​​Gary

FenderBean

Genius! haha

Viper1GJ

My Feedback: (20)

Pushrod corrections

Well after being away for a week with a house full of small grandkids I finally got back to the shop today for an hour with a "I don't care" attitude and decided to chop up the pushrods and make them correct size. If this does not come out satisfactory then I will just reorder stuff and start over.



I laid out the parts from the scrap box I have and measured for cutting. The left rod is too long so I planned to cut out a section and shorten it. The right rod is just slightly short so I will lengthen it a little. The aluminum tube fits snugly inside the 6mm CF tube with no slop. The plan is to insert a piece of aluminum tubing inside the 6mm CF tube for a splice and epoxy in at the correct length. Then I will slide a piece of 8mm CF tube over the joint and epoxy that in place. The push rod compression and tension load will be carried over the splice by the 8mm CF tube.


Parts cut and test fitted, These gaps are extra wide just for the photo. When in proper place there is almost no gap between the 6mm CF rod pieces.


Here the right push rod (top) is dry fit in final form. The left push rod (bottom) shows the separate parts ready for assembly. Next I will install the pushrods with the stabs taped on the fuse fillets and turn on the servos. I will recheck all the servo arm spline settings, subtrims, and endpoint adjustments to make sure the push rods are epoxied together with everything centered.

I stopped here tonight and will epoxy everything together tomorrow after I get some rest. After a full fay of catch up house chores and two appointments (dentist and eye doc) I didn't want to screw it up again from being tired.

Viper1GJ

My Feedback: (20)

Splicing pushrods



Stabs are taped in position to fuse


The servos were turned on and checked for arm spline attachment, subtrim, 100% travel, and endpoints. After making sure the servos were symmetrical, epoxy was applied to the aluminum splice tube and then it was inserted inside the 6mm CF pushrod. Then the pushrod was installed on the stab horn and servo arm and adjusted to proper length and bolt inserted in servo arm.


This is the gap on the left side, about 4mm, after adjusting the splice to proper length.


Excess epoxy cleaned off inner 6mm rod and the 8mm sleeve was slid over the splice to keep it straight during cure.


Left side done the same way


About a 2mm gap on the right side.


Servo battery disconnected and splice joints allowed to cure.

Viper1GJ

My Feedback: (20)

Installing CF sleeves over the pushrod splices


Pushrod splice joints cured and 8mm sleeves ready to install


Epoxy mixed and applied to pushrods


8mm sleeves rotated and pushed against the aluminum rod cap.


Epoxy reapplied behind sleeves and sleeves pushed back on push rod to ensure epoxy completely covers the inside of the sleeves


Sleeves pushed back up against the rod caps to final placement and excess epoxy squeeze out removed.


Excess epoxy cleaned off push rods with alcohol.


All done and set aside for cure. I think these push rods will work OK. I'll give them the pull test after cure.

FenderBean

Just for piece of mind may just put a pin in the the connection are of the two.

Viper1GJ

My Feedback: (20)

I considered doing that but after pulling and tugging on these I don't think it will be needed. That Six10 epoxy grip is really strong and not brittle.
Thanks

Viper1GJ

My Feedback: (20)

Programming stab servos


Got push rods installed and servos synced up. Endpoints programmed and offset curve used because the full down travel available is less than full up.


Full down


Full up


Full up


Full down. Down travel is limited because the leading edge of the stab root touches the fuse side and stops the down travel. Don't think it is a big deal on this type of jet. Servo end points reduced to keep the stab from touching the fuse. My supervisor is resting in the chair.


Full down


Full up

Down


Up. Feels good to finally have all the flight controls going and programmed.

bonefishfool

My Feedback: (6)

coming along well! Wish I had 1 per cent of your skill, Gary! Hopefully by the time COVID has passed, the Thud will be ready to maiden

Viper1GJ

My Feedback: (20)

Bonefishfool, thanks for the compliments. Still plugging along.