3D Viper-ST 100-120cc scratch build......it continues!

[Terryscustom]

I guess there's not much strength to gain (or needed?) if you went full depth....all the way to the other skin?

Very limited, if anything putting a small rib going back would add lots more. However I've used this same installation on a 43% 170cc MX that I flew pretty hard with 50 degree throws and they held up nicely except I did not harden the blocks and had one come loose. Since then I harden the blocks and never have an issue.

Easy to see, this is for advanced builders.

Why is that?? This is literally a 20 minute project with a hobby knife. Maybe an hour with dry time on the glue. Considerably easier than most other methods. Everything about my design is based on simple strong construction.

Here is the finished product with the blocks hardened and the horns test fit (obviously installed after covering)......now I'm off to cut hinge-line stock.

 

[thelaw]

Easy to see, this is for advanced builders.

It's so easy even I could do it...and I'm a girl!!!

 

[Pistolera]

Maybe Yakman meant..."Advanced builder using simple methods"

 

[Terryscustom]

So I need to sheet the bottom of the rudder and this time I thought I'd add a small block in the tip where I put the radius. This will help against hangar rash as well as tip damage. I was doing some rudder dunking in a shallow puddle with my yellow Viper and I got a little dent......... oops. When in doubt, make sure your pond is more than 1/2" deep for dunking

So I made this corner block out of some scrap 3/8" medium density balsa. I had put carbon tow in the rudder if you remember from the sheeting process so I marked both sides and cut out the chuck with a razor saw. Then glued the chunk in there with wood glue.

Next to sheet the bottom of the rudder you need the grain to run perpendicular to the face for a ton of added strength. I use medium density 1/16" balsa for this, cut some pieces, tape, ca the joints, trace and cut about 1/32" larger than rudder shape. Then attach with wood glue and a caul for clamping.

 

[Terryscustom]

Once that is dry, sand flush on all edges and round the tip.

Then, I was too busy taking pics and forgot to install a hard point for the tail wheel tiller bar. I've forgot this many times so I'm used to it. I use a small basswood block like the hard-points in the wings. Same procedure.......trace, cut, glue, spray and tape with wax paper and a caul. When dry, sand flush.

 

[Terryscustom]

Now it's time to cut some hinge stock. Now there are a wide variety of methods for this and I've had people tell me that my way is not the greatest. But, it is clean, simple and it works for me. I make a list of materials needed and cut the hinge stock out of 1/2" balsa. Purchasing 2" wide strips is the cheapest way to go for this since the 4" strips are typically almost 2.5 times the cost of a 2" strip.

For the Viper kit here is the list:
Rudder = 1 x 1 7/8 x 24 and 1 x 1 3/4 x 24
Stabs = 2 x 1 5/8 x 48
Wings = 2 x 1 3/4 x 48 and 2 x 2 x 48

The angles depend on the width but I typically get all that I can from the edge to the center of the block (typically between 26 and 32 degrees). Then I hinge slightly loose and seal my gaps. This is enough to get 45-50 degrees on all surfaces. The trick is to use a sharp blade. If you don't have a really nice saw blade go down and buy a carbide tipped skill-saw blade (typically $20 or so). These will fit and work fine on a 10" table saw. Here are a few pics of the setup with a feather board and use a push stick for safety!! I also like to run an external dust collection hose or shop-vac above the blade because balsa dust is nasty stuff for your throat.

 

[bbrown2828]

I wish I has this kind of time and talent.. I'm itching to build a kit or a short kit but just don't have the time

Sent from my SAMSUNG-SGH-I337 using Tapatalk

 

[BalsaDust]

Terry I have been looking to get a couple of feather boards for my table saw. That one in the picture looks nice. Mind sharing where you go it from?

 

[Terryscustom]

Terry I have been looking to get a couple of feather boards for my table saw. That one in the picture looks nice. Mind sharing where you go it from?

I'm not sure, I've had it for probably 15 years. Just google "magnetic feather board" and you should get quite a few options. Very nice since it sticks right to the saw top.....no clamps!

 

[lakerider8]

It amazes me when using my table saw with a coarse,carbide tipped saw how clean and smooth the cuts turn out. I use mine for truing sheeting and sizing some balsa. Never tried cutting the ail,elev,rudder stock like you are doing. I do basically the same thing, but use my band saw.