n00bs Gonna Build a Carden

[mark786]

Mini-Wax, yea thats the stuff. My local hardware store only had semi so that what I have been using. I think gloss would be better for clean up.
I maidened mine with no paint on the cowl.

[gareth.ky]

My local wally world had the gloss stuff. I did a Junior Achievement project back in the day where we sold house number and we used this stuff to cover them. At the time Cayman did not have numbered building like the US and they were converting over so they could run the 911 service better. We made a killing.

Fitting the canopy is a . I think I'll leave that for the weekend when I have more light. I'm not planning to glass the hatch. Just fit the canopy and sand the edges smooth. I have some questions for you experienced builders:

Should I cut a hole in the back canopy support (the vertical curved bit at the back) ? It's pretty light and kind of flimsy so I wasn't sure if it should be cut out. It would give access to put a pilot in later.

I'm going to leave one of the 'floor boards' out so a pilot could fit in through there later on as well. Also hopefully you could see the Rx lights and such.

I want to paint the canopy before its applied to the hatch. I'd like to do some light tinting to it but I'm not sure how to do it. I got a tip from the Woodbutcher to clear coat the entire thing, not just the painted parts. Maybe I can do it with a transparent color thinned out in the AutoAir transparent base.

I'm looking for painting gear because I have none. I'm going to be using the AutoAir paints because they are water based and easy to work with and cheap ($6 for a 4oz bottle). The PPG stuff is pretty expensive and has some scary VOCs. I'm not down to stunt my lifespan for a paint job.

I need a compressor and a decent gun. I have an airbrush for doing small stuff like detail lines. Yay, more tools to buy.

[mark786]

I thought the name Gareth sounded a little Carri bean.
I didn't glass my hatch and now I wish I had. I can see the line where the canopy meets the wood. It was nice in the beginning but now it shows just 3 months later.
I have no cutout in the floor or rear. I hope my pilot stays happy.
I went to a lot of trouble to paint my canopy around the edges but when I started to put Ultrakote on the front part I carried it all the way down the sides. This left only the top at the rear paint showing.
Problem is that I used a heat gun on the sides and deformed my canopy some.
Carefull.
Mark

[gareth.ky]

I'm not going to try and hide the line, I'm going to make it look intentional, like on the full scale. I'll keep that heat gun away from the plastic, ouch!



I might try and curve the corners like that too.

[why_fly_high]

	Quote: Originally Posted by mark786
	I thought the name Gareth sounded a little Carri bean. Mark

He's full of cr@p. He's an Okie.

4 Days till beat down.

Dan

[buttface]

OH DON'T HURT UM !!!
At lest not till after the maiden!
Poor guy cant' even build a plane with out getting a beat down...

[gareth.ky]

I asked for it. Needed some motivation to get my butt in gear and 'Git 'R Done'.

There is a contest on the 2nd in Arkansas we want to get to. Gotta have it flying by then!

[iflynething]

Got to post to keep up with this thread. I was waiting on my girlfriend to get off work and went online on my phone and went through 8 pages before she got off and read EVERY SINGLE POST.

I had to get caught up with it.

Great work and it's looking really good

~Michael~

[gareth.ky]

Wow that's dedication, reading every post on a phone! Thank You.

I built the canister mounts last night. I tried doing this earlier in the build, back when the motor box was just assembled. It didn't go so well and I threw out the parts I made. I have the band saw now and this time it went much smoother.

I built the mounts out of 1/4" lite ply. I wanted something kind of thick to give good contact area with the can but still fairly lite. Because of the header and the 2.5 degree right thrust offset the canister does not sit perfectly on the center line of the fuse. Its off to one side and slightly points towards the side wall at the back. So its hard to make the parts up without a lot of fitting. I went for a design that would give me a lot of flexibility in fitting the parts. Its a rectangular frame with a "ring" glued to it. The ring will get the suspension material (silicone fuel tubing).

Since the rings are made up separately they can be moved around to get the fit right. Also if you botch one (I botched 2) you wont throw away all the work you did on the frame. The rings are cut with the "General" brand circle cutter. I cut the inside first to check their fit with the canister. Then later i used the plug that was cut out to locate the piece on the drill press and cut the outer circle. You need to cut the outer circle last because you need some way to clamp the thing down. The first one I had the wrong inner diameter and another one tore through the back layer of the plywood so I wrecked two.



I cut and fit the frames first on the band saw then cut the indies out with the scroll saw. The corners are notched so they key into the rails that support the landing gear and the stringers that will support the tunnel roof later. The tunnel roof/floor or whatever it is will sit right on top.



Fitting up the first ring. With the can in the right place you can just clamp it. The rear mount has much tighter clearances so I did it first.



The I fit the forward mount. I slipped some silicone tubing in to make sure the can was centered in the back ring. Its hard to get the parts out without moving anything so just take a pencil and draw a line and a locator mark (mark that crosses the part boundaries) on the parts so you can line them up later. That's as much as I could get done from 7pm to midnight. Holes for the silicone tubing still need to be drilled and then they can be glued into the fuse.

I'm a little worried that my setup is going to suffer from the "RPM Jump". It seems to be limited to this canister. If I have to lengthen the header then the mounts will be all wrong. I'll give DA a call and see what they have to say.

[FlyguyXII]

looks good Im getting excited to see it all finished lol

[gareth.ky]

Beveling surfaces is a right beotch.

I just trashed 2 hours worth of work on the V-Stab. Mostly because I'm tired and its never a good idea to work on a project when your sleepy. But also because I don't have a bullet proof way to bevel hinges yet.

These are the steps for the two general methods I have seen/tried. They differ primarily in when the beveling is done, either before the hinge material is stuck to the surface or after.

Bevel Before:

1. Edge True the the parts (source of error)
2. Find Center, front and back need to be identical lines (source of error)
3. Mark Hinge Points
4. Cut/drill for hinges
5. Bevel on the bandsaw with the table set to the correct angle, then sand smooth
6. Glue hinge material to surface, carefully aligning with center of surface. (source of error)
7. Trim and shape hinge material to surface

Bevel After:

1. Glue hinge material to surface
2. Trim and shape hinge material to surface
3. Tape the opposing surfaces together (e.g. wing to aileron)
4. Find Center at both ends (source of error, might not be possible!)
5. Mark Hinge Points
6. Cut/drill for hinges
7. Mark bevel at end caps with a jig
8. Mark down sides
9. Cut bevels by hands with microplane & sandpaper (source of error)

Method #2 is somewhat less prone to error and can be done entirely with hand tools. Its got problems with the H-Stab where the surface doesn't have a straight tapered edge. Its also got problems with places where you cant see the ends to find center (like the rudder and ailerons).

Method #1 gets most of the error producing steps out of the way before the hinge goes on the surface. So you just have to control that one single process. Doing that in practice is not as easy as it sounds.

There has got to be something I can do to make this work better. Maybe I just need to go to sleep.

[gareth.ky]

My allergies are killing me today so while the Sudafed kicks in I'll post an update.

Can mounts got drilled for the tubing and glued in place with 30min epoxy + micro balloons. The heat gun really helps get the epoxy flowing so it can get in the right place. I turned by back on the parts while they were setting up and I didn't think there would be a problem because the friction fit is so tight. Well the back mount moved slightly. Not enough to make me want to do anything about it though. No one will see it anyway.



I glued the motor box top in place and made up a servo box for the throttle servo. I haven't mounted the throttle servo box yet. I used CA to build a frame for it as suggested in the instructions and 30 min epoxy to mount the top itself. That CA is pretty impressive stuff. I kinda wish I had left the motor box top off until later. I thought it it needed to be on to mount the cowl but it really wouldn't be a problem it it was off and now its just in the way.



While all this was going on I re-cut the H-Stab. It had to be made about 1/4" shorter to match the plans. The top and bottom were not perpendicular so I cut them both and now it sits square on the fuse. Here you can see I'm using the miter gauge (an Incra 1000) as a cross cut sled. You cant use the fence for this, the part is too big, so having an accurate miter gauge is really useful. In the second shot I'm setting up to do bevels and using the digital level to set the table angle.



Of course I wanted to have the rudder mounted last night but it didn't work out that way. Now I'm out of 3/8" balsa so it will have to wait until Monday night. I think I have some ideas to make it go smoothly this time.

I also made a couple of trips to the hardware store and got all the nuts and bolts for the Cowl. They don't seem to carry T-nuts smaller than 4mm in metric so I had to go with 6-32 sized parts for the cowl. For the little black plastic mounts the plans and instructions call for a number 8 sheet metal screw but that is just too big. I looked over several of Walt's builds and it looks like he is using No. 6 screws which makes more sense. Another bug perhaps?

[gareth.ky]

For once something went smoothly.

The cowl is something I have been afraid to tackle. If you screw it up its kind of permanent. So far though its been a breeze. The fiberglass work is excellent, the cowl halves fit snugly together straight out of the box. I suppose there are pinholes in it somewhere but I cant see or feel them.



I made up the required 1 dozen blind nuts on plywood pads. The kit comes with some 1/8" ply for this but I have never seen a blind nut that short! The ones I get from Ace are at least 1/4" deep so I had to use 1/4" pads. I don't know whats up with that but that's how it is.



I taped the cowl halves together and marked the locations for the holes. The hardware is 6-32 and I used a 1/8" drill bit to drill the holes with a cordless drill. Slow speed works best. You need to get something under the part so you can press on it, I had this piece of scrap 2x4.



The two forward blind nuts on each side had to be shaped slightly so when the screws are tightened the cowl doesn't deform. Before gluing I took everything apart to wash it. Then I put everything back together and taped it as well. For gluing I removed one screw at a time so that nothing could shift. The screws got dipped in Vaseline and the epoxy was applied to the pad. then it was reinstalled before moving on to the next one. Every 15 mins or so I checked that all the screws still moved just in case.

I also had time to make some tools. I had this aluminum I-Beam that I turned in to an edge truer. It looks like a level but Home Depot doesn't know what its for! I put 120 Grit on one side and 220 on the other. Some scrap 2x4 with 120 grit paper is used for pushing the stock. Works great.



The next tool is a little block with a blade stuck to it, simple enough. This is for putting perpendicular notches in the end of bevel stock. The block was cut so that its perfectly square. This eliminates one of the most error prone parts of doing bevels; copying the center line mark from one side of the stock to the other. Really with a pen you line can be 1mm wide and if you are off by the line width on each face your off by 3mm on the other side. If you do that to two opposing surfaces then the accumulated error is 6mm. I think this was the source of a lot of my problems. If you get it wrong you cant see both sides of the part at once so you cant see how bad it is.

[mark786]

Gareth,
Short blind nuts are made and my Ace Hardware does not carry them either. They come in handy in a lot of areas around the plane so you will want to find a source. I found them at Lowes. They are typically sold in two different depths.
Mark

[gareth.ky]

Thanks mark786, If I could get 4 for around the canopy that would be excellent. I'll check Lows Today.