Control rod wear - what are you doing ? solution

[rcmarty]

I'm at 137 flights on the 700 now and I'm finding the wear on the CF control rod is causing the (hollow) rod to make me nervous it will break in flight.

I've even put the chain lube wax on the rod to make it slide easier.

Pictures show the rod beside the holder and how far the holder pulls a bow in the rod. ( there is a slight gravity bow in the rod as I took these pics with the heli inverted )

I've been trying to find or figure something that will support the rod in a more neutral bow , even with a slight downward bow at center to make up for the extreme bows at the 2 max ends of throw.

What have you been doing about this ? Just replace the rod al the time ?

I'd like to get a clamping ring for the boom with a threaded stud to use a balllink to support rod. Easy to make fine adjustments to get a setting that works with the least amount of wear. Ballink and threaded rod an idea used on the goblin line of heli's with the bigbelt kit.

Any thoughts or fixes out there ?

Martin

[FLYGUY 11]

I run 1 long solid piece of threaded rod through the whole carbon tube. I feed epoxy in as I'm inserting it into the carbon tube. Worry free

[wjvail]

X-Cells run (ran) a piece of clear heat shrink over this region. Always seemed to work well. Maybe it'll work on your Mikado?

Bill

[pwood]

Hi guys

I tried the heat shrink tube on my first Logo....used Hirobo clear pushrod tube.
I needed to enlarge the hole on the pushrod support too much....

Took it all off and bought a new support and left it stock.

I run the support offset a little, so when the servo is centred, the pushrod bows one way a little and at full deflection, it bows the other. My logic is that a little rubbing on both sides is better than a lot on one side.

Regards
Paul

[deepak]

I just use a piece of a straw. found that min air teflon would not slide through the clamp.
d

[rcmarty]

I'm hoping to get a clamp ring with a threaded stud made up.

Thinking of putting a brass sleeve over the CF rod where the travel will be going , then using a large link ( like on the XX swash) that will be a little oversized and allow for the deflection of full throws


Trying to keep it simple and light if possible.

Will let you know how I make out.

Martin

[paulmedford]

the straw idea sounds much simpler. Nice touch d ...going to steal that idea and do it on mine!

[deepak]

lol paul,
I see that your enjoying the heli.......
What flight times you getting?
when you coming by the club to show off a bit?
d

[rcmarty]

I managed to figure out a simple fix.
Sometimes the solution comes easy , most times not ( lol )

I got some alum tubing to act as a sleeve for the wear point. ( #104 - 3/16 x .014 inch ) , determine where the travel is going to be , then some extra on each side. A little jb weld worked into it and good to go.
Sleeve in pic 2 1/4" long

I used an old 800 tail rod that had been broken for this project. Will note that this needs to be done with a new rod as the id of the tubing is far smaller than the plastic end pieces. If your having the same issue I had , then just get a new one and replace the entire setup.

Next up is a swash ballink for the XX series. Trimmed it back a bit (23mm end to end total length )

Take the stock mount and cut off the section where the rod would have run.
Drill / ream out the holes in mount for a 3mm bolt to go thru

I used a button head bolt (12mm) and a washer.

Bolt runs thru washer then bracket then into the ball link. ( it's a springy bugger so make sure young kids aren't around to hear and 'misc' comments being made )

Next you need to rotate to get it in position to make the rod straight at center throw.

All done there is a slight (about half of previous bow at center ) and much better defections at full throws. Tubing is a little bit smaller than the link so it allows for minor bowing and up/down/side to side without binding.

Going to give it a try tomorrow , should hold up a lot better I think.

Martin

[mr_squiggle]

Very clever. I'll use that idea!


Citizen #186

[rcmarty]

Only got 1 1/16th of a flight test on it.

Rod survived so more testing to come.

Worked well though.

https://www.helifreak.com/showthread.php?t=646375

Martin

[EEngineer]

Marty, can you show more detail on the boom support brace that is in the picture?

Is it used to prevent "harmonic flapping" of the boom supports in flight?

Thanks

[rcmarty]

It'a a piece of Velcro strap , either end wrapped around boom strut then a tystrap thru a small cut in strap and around the boom strut.

It's not for vibes or harmonic stuff.

It's to keep the boom struts from going into the rotors.

The tail clamp system on the XX's is a poor design (IMO) the 2.5mm bolts tighten up and loosen up the large 3mm bolts , then tighten up the 3mm bolts till the 2.5mm bolts go loose. Take the view of not stressing out the bolts you end up with the 2.5mm bolts tight and the 3mm loose ish causing them to come out and go into blades after 15 or so flights. Or tighten them up good so they won't back out then a few flights later they snap and you guessed it .. into the rotors.

Got the same blade twice

I have a 1 piece tail clamp coming I hope , lynx discontinued them and I hoping I got the last 3 of them.

Martin

Originally Posted by EEngineer

Marty, can you show more detail on the boom support brace that is in the picture?

Is it used to prevent "harmonic flapping" of the boom supports in flight?

Thanks

[hemp]

Originally Posted by rcmarty

Take the view of not stressing out the bolts you end up with the 2.5mm bolts tight and the 3mm loose ish causing them to come out and go into blades after 15 or so flights. Or tighten them up good so they won't back out then a few flights later they snap and you guessed it .. into the rotors.

I've always tightened mine up pretty good and never had one snap (or felt like it might) even in crashes.

Also, I loctite all four screws so they will not back out.

I've never had an issue with the boom support clamp. It's a bit awkward to install, but once on it has been worry free.

[rcmarty]

Did better this time on the 800. Bolt broke at 116 flights. Good thing I have my goofy blade saving strap on there.

So far in 300 ish flights I've had one back out , and 2 break.

Is there a better grade 3mm cap out there ?

I was thinking on way home from field of using a longer bolt with a ny locknut on the topside to keep it from backing out.

This one was slathered in locktite and tensioned up a little less than the first break of one. Note so much locktite that the washers are still there after a half of a flight later. I was doing 2 gentle flights on it figuring that the new tail drive gears could use some breaking in. Tail started to do the goblin chatter on simple piro's. Scared me




Martin

Originally Posted by hemp

I've always tightened mine up pretty good and never had one snap (or felt like it might) even in crashes.

Also, I loctite all four screws so they will not back out.

I've never had an issue with the boom support clamp. It's a bit awkward to install, but once on it has been worry free.

[gashead]

How about trying this, its from the Diablo 700, below is the manual and its on page 42 http://www.minicopter.de/en/diabolo/online-manual
The manual gives you the part numbers and here is the online manual http://www.minicopter.de/catalog/index.php?cPath=60_48
Works great on some of my machines, dont see why it wouldn't work on this?

[sl4ppy]

I do nothing..

A new rod is $11. Just replace it every 300 flights.

[rcmarty]

Are you doing anything to rod to get it to last 300 flights ?

I was more than halfway thru rod at 138 flights.

Martin

[Mentalic]

Originally Posted by rcmarty

Are you doing anything to rod to get it to last 300 flights ?

I was more than halfway thru rod at 138 flights.

Martin

Mine has 445 flights, its not worn at all, just a little shiny. Don't have the support extremely tight and maybe that is helping? Perhaps the location matters as well.