Another Shrike Build - 40" span electric - Page 2 - RC Groups
Shop our Airplanes Products Drone Products Sales
Thread Tools
Nov 09, 2012, 09:38 PM
AndyKunz's Avatar
Thanks, Stefan. Lots of the parts of this plane come from my "scrap" bin.

A little more on the fuselage top hatches before we get back to the nose.

In these photos you can see the magnets in the rear corners of the front hatch, the peg holes in the former, and the hold-down bolt. There's also a photo showing the inside of the hatch lids. They're very simple!

The nose gear door is going to rest on some 1/8" sq balsa. The door outside surface is a compound curve, so we are going to make the hatch flat on the inside with a 1/32" ply liner and then sand the outer 1/8" balsa to match the curves. First I "masked" the door edges so that my sanding bar wouldn't eat into the existing surface, then I removed all the excess balsa.

The cowl will have 2 4-40 bolts holding it on. There are small inlays of 1/32" play to prevent the wood from crushing (they're flush now, but will be sanded smoother later). The two tabs are fastened to the cowl with bolts, then the tabs are epoxied to the firewall. The packing tape serves as a mask to keep epoxy from sticking (it sticks to matte cellophane but not packing tape).

I'm going to be working on the nose gear door mechanics next, getting the door hinged and the servo positioned. The door will be controlled by a sequencer in my DX18.

Sign up now
to remove ads between posts
Nov 10, 2012, 08:34 PM
AndyKunz's Avatar
Ah, the nose door! I love it. Below you can see photos of the door in the open and closed position. The servo is an E-Flite DS-35, and ultra tiny fast servo intended for indoor foamies. I had to change the connector to work with standard equipment (it's set up for an AR6300).

There's also a video of the door and gear working together in that ZIP file. These are driven using the "Basic" pre-defined sequence (second on the list) in the DX18. I adjusted the sequence time down to 3.0 for both directions, and tweaked the door position timing a smidgen. It's really cool being able to use a feature in the transmitter that was a lot of fun to develop.

The door looks a little off. The hinges are only held in place with a little friction. They will be much better after the model is covered and I can align and glue things permanently.

Note when the door is open that there is a rail inside the door for the pushrod to be adjustable in a bunch of different positions. Space those holes as close as you can - mine are spaced 3/32" apart. It makes the setup a lot easier. Also, use a servo horn like the one shown, the T type with 3 holes. Those help. And the little V-bend in the pushrod is to make it adjustable too.

Next step will be wingtips. The glue is already dried, I just have to do some sanding!

Nov 10, 2012, 09:38 PM
Surface, Air & Water Rc Toys..
freechip's Avatar
Not sure what is cooler, the sequencer in action or the Black DX18

Sorry if I missed it but what is the wingspan on this and fuse length?
Last edited by freechip; Nov 10, 2012 at 10:16 PM.
Nov 10, 2012, 10:12 PM
AndyKunz's Avatar
The thread title says 40" but with the wing tips I just finished, it's actually 44". The DX18 is one of the first protos. The length from back of spinner to end of fuselage is 27.5" but the elevators will extend a little further back.

OK, wingtips.

The tips are made by sandwiching some balsa. The center core is a piece of 1/4" balsa (cut to rough shape) with the grain running chordwise. This is because the wood extends behind the wing to end with the aileron TE, and this makes it a little stronger. The top and bottom pieces are 3/16" with the grain running spanwise. This is easier to sand to the airfoil. This sandwich is clamped between two solid blocks and clamped overnight.

I didn't show it, but you can do a good bit of ligthening of the wingtip by removing wood from the 1/4" section before gluing the sandwich together.

The root side is then sanded square then glued to the wing tip. Note how the inner layer can be lined up to serve as a reference later when sanding. The glue again is given plenty of time to cure.

After the glue dries you can do a little carving and then sanding. I use blue masking tape at the root to keep from sanding the whole wing skin down to nothing The paper is coarse and attached to a real long sanding bar. This ensures a good airfoil shape matching the wing cleanly.

Next the tips are rounded with a smaller block not as coarse, then lighter grit, and finally with the flexible sander.

As you sand the airfoil to shape you will notice that the layers provide a good reference to how evenly you sanded.

Last edited by AndyKunz; Nov 10, 2012 at 10:19 PM.
Nov 11, 2012, 12:48 AM
Always trying to learn
mejmea's Avatar
Wow, very impressive! Looks like it will be a lot of fun. The "stealth" Dx18 is very cool - is that where all of the secret firmware tests take place before public release? I'll bet it doesn't even show up on radar.

The dust collector was a great addition for your long term health - make sure you have/get some high quality filtering on the outlet.

From the looks of things in the shop, the work that you do during the day, and the number of threads you keep track of here, sleep must be optional.......!
Nov 11, 2012, 03:03 AM
U.K. or New Zealand
FlyingKiwi22's Avatar
Nov 11, 2012, 09:39 AM
AndyKunz's Avatar
Sometimes I go for long periods without sleep, often 16-18 hours a day A lot of this plane was built while I was on vacation last week, or built a year ago in evenings.

Last edited by AndyKunz; Nov 11, 2012 at 02:16 PM.
Nov 11, 2012, 11:09 AM
Registered User
thechannelmast's Avatar


were did you get the plans from thanks for the help
Nov 11, 2012, 02:16 PM
AndyKunz's Avatar
I made them.

Several years ago I used the CD044 plans from Flying Models to draw the outline of the top view in CAD. I scaled it up to 35" span and designed my own structure within that. This one is a scaled-up version of that with some other changes as well.

Nov 14, 2012, 07:52 PM
WILLIAM M's Avatar

I sure do like that retract set up. I looked at the video. awesome !!!
you sure do some nice work.

Nov 15, 2012, 09:01 AM
AndyKunz's Avatar
Thanks, Bill. You're work isn't too shabby either!

Nov 18, 2012, 04:39 PM
AndyKunz's Avatar
I haven't forgotten this thread, just been a little busy this week.

Today I show the elevators being built. I realized I needed to do this before making the servo mounts for elevator and rudder, but also that I needed to coordinate them some.

The elevator is built in two sides. This is just a style thing, and to get useful surface action for a landing flare with the increased outer area.

The frame is 3/8" sq, same as the stab. The single "rib" near the middle will hold the control horn (I'm using the hardware set from the E-Flite Habu 32). It aligns with the servo arm - you'll see that setup later on.

After the frame was dry, I attached it to one side of the sheeting (pre-cut to shape). These will be beveled to give a taper. Attaching the one side of sheeting now makes them stronger and easier to hold while beveling.

I prefer the built-up control surfaces because they are lighter, stronger, and resist warping.

Nov 18, 2012, 05:08 PM
Always trying to learn
mejmea's Avatar
So will you just taper the side that is not sheeted yet (i.e. asymmetrical taper)? I'm not understanding how you could taper the sheeted side without sanding through the sheeting - unless the taper only takes place over the last 3/8 where the framing is?
Nov 19, 2012, 09:38 AM
AndyKunz's Avatar
I'm going to take advantage of a little geometry by making the taper only on one side.

Right now if you look at the side view it's a rectangle. I'll be removing wood from one side only (the unsheeted side) to turn it into a right triangle. Then I'll sheet the remaining side, still keeping a right triangle.

If you lift up the point so that it's halfway up to the max thickness (ie, "neutral" elevator) then you notice that the bottom (first-sheeted) side now has a little gap. I will remove a little more triangle from the LE so that "down elevator" really is down.

I'll try to remember to photograph each step since you asked. Thanks for asking.

Nov 19, 2012, 12:49 PM
Mustang Fever
Just a note here: I have the templates for all the Shrike 40 parts (ribs, bulkheads, etc) and the build book used in the Lanier BIY kits as PDFs and can send them to whoever would like to build one. (No charge, of course) I haven't had my plans scanned in yet, but could do so anytime and send those as well.

My Shrike is plans built from the info I have. The main thing I did differently from the original kit design was to do away with the 1/4 square spruce wing spars, and use 3/8 carbon fiber tubing instead. Much easier to bore round holes than to cut square ones.

Once you've flown a Shrike, you'll always have to have one. They're in a class all by themselves when it comes to handling and grooving. I think mine is also my fifth- 40 kit, 2- 10 kits, 40 ARF, and this 40 scratch build. Took me a long time to correct all the mistakes I made, the biggest being messing with the CG. I left it right at where it shows on the plans for this one, and that prevented troubles.

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Micro Shrike Build Thread (was Mystery Build Thread) AndyKunz Electric Plane Talk 101 Dec 05, 2013 10:50 AM
Build Log San Diego Slopers Shrike build party.. ORANATOR Slope 111 Dec 21, 2012 01:21 AM
another shrike question<s> sylentbob3 High Performance 2 Jun 03, 2005 10:17 AM