n00bs Gonna Build a Carden

[gareth.ky]

Oh man. Never ever measure something when your tired.

I built the truss sides up on Sunday using JMiracles method of putting them right on the skins from the get go. I built over the plans and used a square to set each of the vertical sticks in place. Got done with both of them and put them side by side and they were the same length along one long edge and different lengths along the other edge. So i was like, WTF?!?! I used a SQUARE, how did I make a trapezoid?

I went back over what I did and lo and behold I had a square that wasn't square after all! I used an orange plastic triangle for all the sticks but the ends. On the ends I used this 'Empire' brand L shaped square because there wasn't enough room to use the plastic triangle. Well the 'L' hails from the 'Empire' of the not-so-straight.


In the confusion I wound up installing the wing tube socket supports. Then to correct the problem I put 1/8 balsa strips on the ends of the trusses. And that's when I went to bed, thankfully. Who knows what I would have done next.

With fresh eyes today I see that I only needed the 1/8 strips on the tail end of the trusses. The nose ends were just a hair too long at one corner. The skew in the parts matches up well with the error in the bogus measuring device.

I sanded it out using the good red plastic square as a guide and now its all good. The wing tube socket supports line up perfectly with the plans and each other.

So lesson learned: Don't trust cheap tools from Harbor Freight.

[gareth.ky]

Making up the skins. I cut them at a 45 and joined them and then flipped the other half so the two joins were not next to each other. Did the same with the long 3/8" sticks.


Align the top edge of the skin with the thrust line on the plans.


How I used the square to align each of the pre cut vertical sticks.






This is the error I mentioned in my previous post.


Use the same triangle method to mount the Socket supports. Mount the first one aligned to the plans and then mount the second so it sits flush with the first.




Tail Tube Socket Support. You can see the Bass Wood block I added under the support to eventually mount the blind nut for the anti-rotation root plate.


this is actually a pic of another error. The diagonal stick in the cell to the right of the socket support should be going the other way and the little square ply block should be in the upper left corner. The square ply bit is the location of the forward canopy hold down. I made the error on one side and decided to just make it look like it was SUPPOSED to be that way, instead of trying to dig the stick out. Both sides are identical.


Template of the anti-rotation root rib for the stab. You can see the tabs line up over the hardwood mounting blocks.


Quick check to make sure the wing tube hole in the motor box ligns up vertically with the hole in the truss side. Good to go.

And now, its Rum & Coke Time!

[gareth.ky]

The next job is to trim the fat from the motor box and assemble it. Being a noob I don't know exactly what I should be cutting away. There are some practical restrictions on what you can cut. F2 & F3 are butt joined to the motor box so contact area is critical to the strength of those joints. Most of the cutouts for the motor box sides leave the entire joint line intact and that seems smart. Luckily FG has some good Carden build threads with examples:






So you can see there are lots of ways to do it. The last one is Ivan Kristensen's 40% 260 and his mods are supposedly have the blessing of Carden. They are also some of the most aggressive in terms of material removed. I would really like to see a finished weight of 25 pounds so I'm really going to be pretty aggressive with the weight removal. The one I really like is Levi Jordan's:



This is the prototype of the laser cut motor box he is selling:

[gareth.ky]

I love CAD:
35% 260 cutouts.png

[why_fly_high]

Looks good!

Dan

[gareth.ky]

Thanks!

156 holes... it took 2 hours... to drill... them all...

[gareth.ky]

...and 4 hours to cut all the chunks out. The patient responds well to diet! Lost 19oz! Pics and stuff later.

[gareth.ky]

Ok, so it wasn't quite 19oz, I forgot to weigh a part. I saved 18.7oz or 530g. That puts the target weight almost exactly 25 pounds. Some more lightening mods can bring that down further. I'm pretty happy about that


My Templates, Let me show u them. If the thing doesn't implode I'll make the files available. Someone just remind me to do it. I made a PDF and got it printed at Kinkos. Then I stuck the templates on the parts with 3M Mount Spray.

The patient shows signs of obesity. The Doctor recommends diet and exercise.

This went on for about 4 hours. I learned a lot about using the scroll saw. How to get the right speed, tension, lighting and saw blade etc. Some of the early cuts are really rough. The later ones are pretty good.

All Done. It looks all impressive but it you get up close you can see the wavy lines, yuck. I spent some time sanding all the cut edges to make it looks a bit better.

The patient shows much progress.

Mocking up the motor box to make sure it all fits like I planned.

[gareth.ky]

And now, boring video of me using the scroll saw. Just don't watch this, its boring. It went on for 4 bleeding hours! You think your going to build a Carden? You think that's air your breathing now?

[skyesdad]

Dude that looks great.And scroll saws

[gareth.ky]

UPS just dropped off the motor and exhaust from DA. I'm sitting here in the office with a DA-85 on my desk smelling like gas and big goofy grin on my face.

[why_fly_high]

	Quote: Originally Posted by gareth.ky
	big goofy grin on my face.

Nothing new there! I would have gotten the 100.

Just messin' with you. I think this is going to be awesome!

Dan