Dave A

My Feedback: (1)

Has anyone found a good alternative to the aluminum hinge rod that goes in the Comp-Arf elevators?

I pulled mine out to do some hinge work and found the rod to be worn quite a bit where the hinges rub. Which is contributing to the slop in the elevators. The existing rod is very light weight and soft.

I would like to get a more durable rod even if it weighs more. Has anyone tried a brass rod?

I've read about people using nylon bushings to keep from wearing the hing holes. A brass rod with nylon bushing would be perfect and durable.

Anyone have a diameter for the existing rod?

Dave

Rezagh

My Feedback: (73)

Dave,

Existing rod is 2mm if you have the 2.3. I assume it's the same thing for bigger planes but can't say for sure. Their design as far as hinge goes, is really poor in my oppinion. Most people run into the same issue after 100 flight or so. Those nylon bushing you are talking about is the way they come from factory I beleive at least on the 2.3. Rod goes through those guides and when they fall off their place, you need to actually cut the stab to be able to glue them back. Rod should be your least concern because it's matter of minutes to replace with no cutting or repair. See if you still have the plastic guides in place.

rcblimppro

I ran a CF rod on mine. When I got the airplane it had quite alot of use on it. What I did was wax up a peice of music wire of the same size, in my case it was 5/23 as the hinge rod was 4mm. I slid the waxed rod into the tabs without the elevator. I then sarurated the hole where the rod went through the tabs with medium CA. After a couple of hours I gave the rod a twist and then pulled it out. The result was a nice tight fit for the CF rod.


Shawn

Dave A

My Feedback: (1)

Thanks for the info guys.

Mine is the 2.6M Yak.

Shawn, how is the CA/CF rod holding up for you? I was thinking CF rod, but I was thinking it would wear too much.

Dave

Dean Bird

My Feedback: (39)

Hi Dave,

I haven't seen the hardware for the 2.6mm Yak, so I'm not sure on the rod diameter. I can give you the sources for the 4mm stuff we use on the 3.0m planes.

The nylon bearings come from McMaster-Carr.

http://www.mcmaster.com/

The bearing we use is part number 7817k33. Put that part number is the search box at the upper left and it will take you to the catalog page with that part number highlighted in yellow. It is designed for a 4mm "shaft", a 5.2mm "hole", and is designed for a "sheet thickness" of 1.45 to 2.34 mm. The single thickness phenolic arms are about 2mm thick.

The idea of the bearing is to get more surface on the tube so the load is supported across a bigger surface.

Special Shapes is the source for our 4mm brass tubing.

http://www.specialshapes.com/brasstu...sp?product=017

It's .017 wall brass tubing with a 4mm diameter. It is part number 90074 on that page and you would order the 36" lengths.

I put carbon rods in my first 3.0m Extra but didn't have it long enough to see how it held up. Here is a source for the 4mm carbon materials.

[link=http://www.timgoldstein.com/secure/estore/Category.asp?Cguid={28551D64-143A-481C-9502-88653B07652F}&Category=ModelSupplies%3ACarbon+Pultrusion]http://www.timgoldstein.com/secure/estore/Category.asp?Cguid={28551D64-143A-481C-9502-88653B07652F}&Category=ModelSupplies%3ACarbon Pultrusion[/link]

Part number ACT-157 is a 4mm carbon rod that is 48" long. Part MCR-156 is a carbon tube that is 29.5" long. Take your pick if you want to go with carbon.

There are some pictures of the nylon bearing being installed on the 2nd page of the build thread for my Composite-ARF Extra 260.

http://www.teamflyingcirkus.com/foru...hp?t=94&page=2

Hopefully these sources will be helpful.

Take care,

Dean

Dave A

My Feedback: (1)

Dean,

Outstanding work and info! It looks like the 2.6M uses the 4mm rod as well. I'm going to get some items on order and see if I can get this knocked out. I've really enjoyed my Comp-Arf, but there are some issues that need to be taken care of over time. If some of these issues were taken care of up front they would never surface. I like how you reinforced some of the corners. Many of my corners have chips and cracks in them. And now I'm out of commission until I get the elevators fixed.

Thanks again.

Dave

rcblimppro

I had about 150 flights on mine before I sold it after the mod and it was holding up well. There are two ways to prolong the rods life. Deans works well but at the time I did mine was the night before I had planned to go flying. There are aluminum tubes in the stab that are supposed to provide the bearing surface. The rod is actually supposed to be tight enough in the tabs so it will not rotate thus the aliminum tubes provide the bearing surface and less wear. The problem is that aluminum to aluminum and Cf to aluminum are poor bearing surfaces ( Read high wear ). Having the rod rotate in a nylon bushing really is the better way to go.


Shawn

Dave A

My Feedback: (1)

Shawn,

I see what you are saying. Your method snugged up the rod in the horizonal stab. tabs and allowed it to rotate in the elevator (which was Comp-ARFs intent). Mine is so sloppy in the horizonal stab tabs that I thought it was suppose rotate there. Was the hole in your elevator still snug or was it elongated from wear?

Dave

DoggyDoo

I've got a Stick that has slop about anywhere and everywhere there can be slop and it flies fine.

You just need to learn to fly, man! [sm=biggrin.gif]