Installing Bearings in Composite Arf Phenolic Hinges (Rudder/Elevator Hinges)...

[murry]

McMaster also sells a good stainless steel rod part # 50415 K211, 4mm OD, 3.5mm ID

[notorious_benny]

http://www.flyinggiants.com/forums/f...tml#post115428

Heres some pictures of the bearing mod on my super extra........

[Kiwi]

Kris,

Who said you cant teach an old dog new tricks. That system of using the brass rod only in the bearing area and a smaller carbon guide rod sounds bloody excellent.

I know if you use the three brass tubes it adds a good chunk of weight to the tail but the tubes in small offcuts lined up with the bearings would work like a hot dang.

My only advise is range test and range test and then once you sure sure there's no problems do another range test because those carbon tubes in a C-ARF have caused some serious grief before.

I'm doing this on the YAK anyway to see how it goes.

[JagerBomb]

has anybody weighed the diff between the brass tube and a stainless one?

Mark

[KrisW]

	Quote: Originally Posted by JagerBomb
	has anybody weighed the diff between the brass tube and a stainless one? Mark

Actually, Brass/Bronze and iron are within 10% of the same weight, so the tubes would be approximately the same weight .. within a few grams, with the brass tube being slightly lighter for the same wall thickness and diameter.

[KrisW]

	Quote: Originally Posted by Kiwi
	Kris, Who said you cant teach an old dog new tricks. That system of using the brass rod only in the bearing area and a smaller carbon guide rod sounds bloody excellent. I know if you use the three brass tubes it adds a good chunk of weight to the tail but the tubes in small offcuts lined up with the bearings would work like a hot dang. My only advise is range test and range test and then once you sure sure there's no problems do another range test because those carbon tubes in a C-ARF have caused some serious grief before. I'm doing this on the YAK anyway to see how it goes.

Actually, it's what I use to replace the stock setup, Kiwi. The RF problem, given the location and size of the CF rods, is a non factor. Besides, RF is blocked by steel, copper, brass, aluminum, or any other metal as well, so no matter what you put in there for a hinge pin, other than fiberglass rod (which they make, btw. . CHEAP too, bout 1/2 the cost of the carbon, though a touch heavier) or wooden dowel (again, which they make in 1/8" diameter) will attenuate the RF hitting it, though to such a small extent it's not even measurable (at least on 72mhz .. 2.4 might have lockouts and crashes. . ) Add in the aluminum sleeve bearings in the control surface, with only small gaps between them where they are glued into place, and you have a 5mm line, along each hingeline, that would be an RF magnet. If there was a problem, it would have been known before now.

Since the only place you need strength is where the brass tube will reside, you could easily use a hardwood guide dowel. Anyone compared the weight of 1/8" hardwood dowel to 1/8" carbon shaft? They are about the same, with the wood actually being a touch lighter, though the CF is immeasurably stronger, but only in tension, which is a non factor since the brass tubes take all the bearing forces loaded in shear.

Kind of puts a damper on all the "hi tech" solutions we have come up with. Good olde WOOD is still GOOD. . .hmm Tony Russo is right. . Wood IS Good. .

Anyone considered a piece of NyRod inside the brass pivot pieces??? It also would work, and be even lighter than wooden dowel.

As for olde dogs .. . .WOOF!!! hehehehehe

[Kiwi]

Kris,

Your on the money with what you say but the carbon rod has caused some very big issues so far with C-ARF owners. Its not like I think it might happen. It does, it has and some planes are un-flyable with it because it is just that bad.

Anyway it was a comment and no need to debate a dead duck but I like your idea of the dowel or the fiberglass rod. Funny I just installed a fiber optic system in my workshop and in the cable was a fiberglass rod. Of course me being a kleptomaniac, I put it away thinking it might come in handy one day.

[KrisW]

	Quote: Originally Posted by Kiwi
	Kris, Your on the money with what you say but the carbon rod has caused some very big issues so far with C-ARF owners. Its not like I think it might happen. It does, it has and some planes are un-flyable with it because it is just that bad. Anyway it was a comment and no need to debate a dead duck but I like your idea of the dowel or the fiberglass rod. Funny I just installed a fiber optic system in my workshop and in the cable was a fiberglass rod. Of course me being a kleptomaniac, I put it away thinking it might come in handy one day.

Yeah, there's too much to debate over the littlest thing in this hobby. Here' we have listed about 6-7 different ways to just hinge a control surface .. none are really "The Best", and they all work great. It's just a matter of what you want to do, how anal you are about RF signal interference and how deep your wallet is.

In the end, they all work. Pick one and have fun.

[Jan Eirik]

I got this reply on my order at mcmaster.com today:
"Jan,
Due to the ever-increasing complexity of U.S. Export regulations,
McMaster-Carr has decided to only accept orders from a few,
long-established customers of ours overseas. We cannot accept your order
and regret any inconvenience this causes you.

Alex
"

Does anbody kow of another re-seller of the Sleeve Bearings part number 7817K53 ?

mvh.: Jan Eirik - in Oslo Norway, jaeioluf@online.no

[jon595]

I used this company to supply what i needed.

http://www.limacproducts.com/

Cheers,
Jon

[kwilson]

Thanks Jon,

I just ordered the full set with new SS hinge pins. Looks like a nice set up.

Kevin

[forgues research]

	Quote: Originally Posted by japan3d
	I used these bearings from McMaster Carr for y 3m Extra elevators. Part Number 7817K33 I used a metric step drill to enlarge the holes in the inner,middle and outboard phenolic hinges.

You mean McMaster Carr shipped to Japan?? wow they won't even ship to Canada,

Roger

[japan3d]

Well they shipped them to an FPO address. Not actually a Japan address.

[wmat7039]

	Quote: Originally Posted by Paul Cataldo
	Guys, WHERE have I seen this procedure done on the net? I swear a while back, I saw someone who had actually installed little round roller bearings? (I think) in the hinges of the rudder, and POSSIBLY the elevator TOO.? Not sure about the elevator, but I KNOW I saw them in the rudder hinges. I cannot for the life of me, remember WHERE I saw this, and on WHICH Composite Arf plane it was on. However, I DO remember seeing this somewhere, and I'm 90% sure it was on a Composite Arf brand plane, at least 2.6m, or maybe even a larger one. Can anyone help here?Has ANYONE here EVER done this mod to their plane? HOW do you drill out the phenolic hinges for the bearings? Do you possibly have to use a 90 degree angle drilling attachment for a Dremel tool? More importantly, I would like to know HOW the bearings are held/fastened in the phenolic hinges???? Is Aeropoxy/Hysol 9462 used???? Finally, has anyone EVER experienced significant wear between the aluminum hinge pin and the phenolic hinge points???? I would think that someone, somewhere has, otherwise no one would have ever decided to start putting bearings in their hinge points. I wonder how bad the wear can be, and how long (after how many flights?) does it take to get this much wear in your hinge points????? Now for those who just cannot handle seeing guys perform cool modifications to their planes, and for those who are absolutely dying to jump in here and say that this mod is unnecessary, then let me lay out a disclaimer and say YES, I KNOW that bearings in phenolic hinge points are not necessarily needed, but I think it's an interesting mod, and if nothing more, I'd like to obtain more info on this procedure. Thanks so much for any help guys....

Here is where it all started from in 2007:
http://www.flyinggiants.com/forums/f...5sp-build.html
Wayne

[reyn3545]

I've always used bocabearings.com

They have tiny roller and ball bearings that work great, will not wear out like the McMaster-Carr ones eventually will. I generally use a 5mm outside diameter, 3mm inside diameter... depending on the size of the hinge rod. Just drill out the hole in the phoenolic arm to match the outer diameter of the bearing, then a drop of CA or epoxy to hold it in place. works great, and no slop.... ever.