3m CompArf YAK 55sp Build

[wmat7039]

Well all... I am fortunate to have access to a CompArf 3m Yak 55sp which just arrived today from Thailand. Andy Kane arranged the arrival through ConWay shipping. From the moment the package left the warehouse in Nevada to the time of delivery, I received on-line tracking email information throughout the entire route of the shipment. Through Colorado into Atlanta & finally Cartersville where I opted to pick it up instead of having it delivered. No need to have the possibility of a fork-lift at destination go through the sides. The plywood box was extremely sturdy & the interior packaging was compact & well thought out. No damage at all....whew..... I feasted my eyes on this brute of a baby!

I just could not resist.....I HAD to assemble her as soon as I pulled in the driveway. At 106 degrees in Atlanta, I put her together to see how well the parts fit. Pristine is the word! The fairing on the wings butted right up to the fuselage. The painted stripes matched perfect to the cowl & she was a beauty to behold.

Well...I had to break myself away to do embroidery (work) but sneaked in the room every 20 minutes to look. The entire kit is fully built.....very little is left to do other than actual assembly & some gluing. It's similar to all the other CompArf aircraft.... It can be up in the air flying in a week, depending on how much time you want to put into it.... The Instruction Manual is very comprehensive and detailed & gives you a step by step method for proper completion.

Having built 3 prior CompArf models, I have developed my own method & tend to follow my experiences...but I absolutely go through the entire manual first & then proceed with my method.

Tonight, I started on the stabs. I will be using one (1) JR 8711 on each elevator half as the kit does not call for two servos on each elevator. This definitely will lighten up the back end. They call for doublers to be used where the servo is bolted in (& it's supplied in the kit). I used toothpicks to line up the holes & pressed down the doubler after putting glue on the surface. After "kicking" it, I used a needle nose pliers to extract the toothpicks..easy job after thinking it through.

Next I pulled out the elevator 4mm aluminum tube & drilled out the holes in the phenolic arms to 5.2mm diameter. Then using a small round file I opened it up slightly so that I could slip in the McMaster Carr nylon bearings. I have used these on all my CompArf airplanes to delete the hinge slop that develops after 60-70 flights. It takes a little time, but well worth it in the long run. NO sloppy hinges for me!!! The McMaster Carr part # is 7817K33 & the thrust bearing has an inside dia. of 4mm, which is the outside dia. of the aluminum tube. The slots in the elevator side have to be widened a bit with a small flat file so that the slight increase in width of the bearings can slip through the opening.

After putting the two halves together, you have to carefully slide the 4mm tube back in through the holes. Just be patient & don't force it in...just keep turning the tube as it's being inserted & she should go right in.

After that, I checked the centering of my elevator servos through the PowerBox & installed SWB 1.25" metal arms with blue locktite. Then I placed the 8711 in the opening & screwed it in using the longer metric screws that comes with the kit. DO NOT use the regular JR screws that come with the servos as these are too small for the holes that are pre-drilled in the stabs & will probably fail after a short time.

I'm not shooting to finish her in a week, since I'm not hard pressed...so I'll work on her at my convenience...
Here are some shots of today & also of the stab assembly.

Got to get some rest tonight...see you tomorrow.
Wayne

[prizzy]

I can't wait to see this one!!!! Good luck Wayne, I will be watching closley.

[JagerBomb]

Wayne,
Thanks for the tip on the bushings. i jumped on the Mcmaster-Carr website and they were super easy to order from. I bought 50 of them to outfit all my planes including the 2 I'm working on now. A good friend of mine just ordered a white 3.0 Yak which I will assemble for him. A mod I've been doing lately is to install a push pull rudder as opposed to the pull pull stock setup. it is very effective and trouble free. Let me know if you need some pics. I'm sure you will love the way she flies!!!

[Howie]

McMaster Carr are going to wonder whats going on. I just jumped on and ordered 200 pcs too.

I think those bushings are perfect. Why have you been keeping this from us Wayne?

We have in the past used small flange ball bearings but the OD of the bearing is 7 or 8mm which leaves very little of the phenolic material.

Thanks for the tip Wayne.

[Kiwi]

Mmmmm!!! Howie,

We wont accuse you of sleeping under a warm rock but then again you never know eh mate!!

I've put this mod up along with a lot of other guys for the past two years or so and my SX has way over a 1000 flights on it and the elevator and rudder as as tight as the day I installed them. I use one of those stepping drill bits and twist it between the fingers to open up the holes. As it's self centering you dont have any problems with the elevator or rudder pin alignment.

In the rudder post I use two small ball bearings on the upper and lower hinge pin as they are doubled up and the wee plastic thingies cannot be used in those two.

I use a carbon fiber rod as the hinge pin as the brass tubing will not pass through the bearings as its a Mick hair too tight. (No slur on Dakers in that remark either). Its an extremely neat fit and there is just zero slop at all in the rudder pin.

The elevator I use a brass rod but its not fuel tube. Its exactly 4mm or some size like that and I can buy it in 24 inch lengths. What I like to do with it is solder a small brass washer on one end and feed it into the elevator from the inside. That way if the pin walks out over time it does not drill a neat hole in your vertical fin. (Ask me how I know that can happen.)

I've seen guys use carbon rod in the elevator hinge and have a hellish time with RF issues. I personally never used the carbon in the elevator and stuck with the brass tube but if you were going to run a 2.4 Ghz setup I suppose the RF issue might be mute.

Anyway Howie old mate, if you want info on those bearings I can get it for you as I have my bag of bushings and bearings in stock for the next ten C-ARF's I might end with one day.

[Imac Kiwi]

Used custom made nylon bushes in the Red Bull Comp-Arf 3M Extra 330 with 4mm alloy knitting needles for the hinges. Works great with zero slop after 100 plus flights.

[wmat7039]

	Quote: Originally Posted by JagerBomb
	Wayne, Thanks for the tip on the bushings. i jumped on the Mcmaster-Carr website and they were super easy to order from. I bought 50 of them to outfit all my planes including the 2 I'm working on now. A good friend of mine just ordered a white 3.0 Yak which I will assemble for him. A mod I've been doing lately is to install a push pull rudder as opposed to the pull pull stock setup. it is very effective and trouble free. Let me know if you need some pics. I'm sure you will love the way she flies!!!

Hi there Mark & All. I certainly won't take credit for the "discovery" of these gems. In actuality, I was discussing the slop in the hinge line issue with Kris Welter in December 2004 & it was he who suggested I try these. I ordered them on December 27 2004 & also ordered 50415K118 This is a stainless steel 4mm tube that I used on my first Super Extra which eventually ended up with 774 flights before I sold it. It's still alive & flying very well..with NO slop in the elevators. Subsequent to this, I use the original aluminum tube, since the stainless steel tube was twice the weight. Other persons went to the ball bearings option but to me, the hole had to be drilled too large for my liking.

I tried the Rudder push/pull option on my/our last project & it worked well with only (2) JR 8711 servos..but I found that I had to add weight to the front of the cowl to balance the airplane even with the PowerBox/ignition batteries all the way to the front & in addition had to use a solid back-plate for the spinner.... On this project, I will use the SWB pull/pull which I've used on the last 3 CompArf projects.

The elevator servo is now screwed in & secure in one stab. I will elongate the hole for proper servo travel & try to match Joe's perfect cut in the stab skin of his Katana. I am NOT noted for my finishing techniques in hole cutting. I'm actually ashamed to show you a photo of the CompArf Extra 260.
Wayne

[prizzy]

Just a note, the bushings and rod cost under $20. Comp-arf will charge you $100 for the setup.

[prizzy]

Wayne, it looks like you may be going for some 3d with this bird, judging buy the servo arm???

[KrisW]

Congratulations on the new BABY, Wayne. glad you finally got her.

BTW .don't give me so much credit on the hinge repair setup, I got it from someone else (I can't remember who, though), and I still use the aluminum tubes in my last Comp-Arf (my original super lightweight 3M w/BME power).

Can't wait to hear how she flies, and what the AUW comes out at.

BTW, Wayne, being that a solid fix is better than a repair farther down the road, I'd suggest visiting the idea of over-gluing the hingepin sleeves inside the control surfaces. With your past experiences with the design, it might be a good idea to wick thin CA into area around the aluminum sleeves, to ensure they do not become separated somewhere down the road.

[wmat7039]

	Quote: Originally Posted by prizzy
	Wayne, it looks like you may be going for some 3d with this bird, judging buy the servo arm???

Hey Pride...I had 1.50 arms laying down here...so I used them...but I will move the ball links to the next hole in @ 1.25" and gain some mechanical advantage, since the control horns seem to be @ 1.75" from center. I may do some 3D with this one...but my priority is for sequence work. It really depends on how it performs. The 260 seems to be a bit better adapted to 3D & I've been trying some stuff with it.
Wayne

[Flyinrazrback]

I also use the bushings in my comp arf, I replace the aluminum tubes with 4mm carbon tubes, nice snug fit and no wear so far.

[wmat7039]

	Quote: Originally Posted by KrisW
	Congratulations on the new BABY, Wayne. glad you finally got her. BTW .don't give me so much credit on the hinge repair setup, I got it from someone else (I can't remember who, though), and I still use the aluminum tubes in my last Comp-Arf (my original super lightweight 3M w/BME power). Can't wait to hear how she flies, and what the AUW comes out at. BTW, Wayne, being that a solid fix is better than a repair farther down the road, I'd suggest visiting the idea of over-gluing the hingepin sleeves inside the control surfaces. With your past experiences with the design, it might be a good idea to wick thin CA into area around the aluminum sleeves, to ensure they do not become separated somewhere down the road.

Hey Kris....Welcome back.....I know what you are saying about the "Hinge pin sleeves"....but I think it hard to cut away the beautifully curved front of the control surfaces right now to glue them in..... You & I KNOW that they will "let go" eventually though....but I would prefer to get her on the road first & then bitch about it later.
Wayne

[ifly3d]

Do I see another freestyle in the future ???

[wmat7039]

	Quote: Originally Posted by ifly3d
	Do I see another freestyle in the future ???

Yep....Dreadlocks & all....
W