Focke-Wulf
FW-190A8 Shrike
The Butcher-Bird

Specs:
Size: 500XTH Brushless
Weight: Aprox ??Oz
Span: ~45-3/16 Inches
Prop: 1280EP GWS
Material: FFF DOW Protection III / Pink EPS
Skill: Moderate

Contact Info:

Questions or Comments?
erik@foamcasualty.com
July 2011: FW-190A Plans are now up for grabs! Get them while they are hot! If you need parts for any kit please send me an email!
July 2011: Kits will be available soon, parts are available now! If you are interested, please email me at erik@foamcasualty.com

THE FW-190(A8)

The FW-190, a purposeful looking war plane, distinct, aggressive, was the answer to the Spitfire. Known as the Shrike, a bird that impales it's prey on thorns, once airborne it's easy to see why it was called the butcher-bird. The 190 shattered the belief that high performance agile aircraft had to have in line design similar to the BF-109. Another long time favorite of mine, this scratch built Focke-Wulf is the second RC of the type I own now. The first I've owned was the Horizon Hobby Parkzone 190, a superb flyer, obtained for quite a bargain off eBay. Somewhat sad to say, my scratch build blows it out of the water. It could be the larger wingspan, or the fact that I built it myself, or the insane power plant, but flying your own is just more fun.

DISCLAIMER: I wanted to make a bit more of a build log then I will be able to, as of accidental nature of memory cards and computers go, things got deleted, accidentally... The good news is that SOME of the build pics were recovered. But the process has been slowed. Also dragging this build log behind is the troublesome computing issues in general I am having as of late. Recently I've switched to Linux, ubuntu specifically, and it seems to be having some teething issues on web page design, making it extreamly difficult to save my work, but this could be related to my web host.

I assembled the 190 fuselage following the same pattern as I used assembling the P-51D, printed the Sketchup plans, transferred them to the DOW Protection Board III, cut them out with my X-acto knife, followed by a rolling and gluing process. Worthy of note for those making their own Sketchup models in this manner, I found that the 1/8 inch offset wasn't quite enough for the smoothed out first 4 profiles. A better number would be a 3/16 offset. Previously I used simple 8 sided circles, and found that an 1/8 inch offset was perfect, however being more exact calls for more exact offsets.

FW-190, FW190, RC cockpit close up

As an added step, I removed the layer of plastic and applied lightweight Spackle to the cracks and sanded it smooth. For the most part this filled all the cracks, but it did require some patching up when painting. -Not a big deal. I was amazed on how flexible the Spackle is when dry. Many people have been doing this for some time, but this was the first I have attempted to use it and I am glad I did. Still, I not sure I would take this step if you are not sure your own invention will fly. It's not that it took excessively long, but it did take more time, and I wouldn't want anyone to get discouraged.

FW-190, FW190, RC

Since I decided I was going to take my time to actually finish this one, I decided to fiberglass most of the fuselage. As I build more and more planes, I'm finding myself fiber-glassing more and more. I guess with practice it becomes easier and easier. Looking back I should have just done the entire plane.

FW-190, FW190, RC

From flying the Parkzone I knew the 190 could be a tad tricky to land, as it seems to have a high stall speed. The addition of flaps would be a major help. This presented me a problem in the wing as the flaps are deeper in the chord then the ailerons, my standard torque rod method wouldn't work nor did I want to use 5-6 servos instead of 4. To make the story short I ended up using a method I seen on kits by Rabid Models, where a string is used to make a pull-pull setup. There are a few tricks, in this method, but basically the use of a strong glue such as Gorilla Glue should be used, instead of hot glue that can melt in the sunlight. This produces a slop free setup that is easily adjustable. The guys over there at Rabid Models really know what they are doing especially if you are into profile flyers. To small for my A123s, but if you've got some light weight lipos I'd recommend checking them out. Flaps are then controlled by a single servo, and I pleased to report they work perfectly for nice soft poofy landings.

FW-190, FW190, RC

My FW-190 in a slight right bank.

FW-190, FW190, RC

A nice profile shot of the butcher climbing.

FW-190, FW190, RC

Here's a close up of the foam carved pilot. A slight forward hunch makes him look like he's pulling some high Gs, or taking a... never mind.

FW-190, FW190, RC

I'm not trying to promote a political agenda here, but the FW-190 was a Nazi Germany warbird. I try to build to scale and that includes historical markings, it's as simple as that, nothing more, nothing less. This shot shows some of the detail painting that can be done with an airbrush. The rudder surface was done with a paper template cut to show the neat looking design.

FW-190, FW190, RC

On the ground after a nice landing, flaps still fully deployed. Oops! Where did that spinner go? Must poped off on the previous landing when it was really windy!

File Recovery

The Ruin-in-er destroyed many of the pictures I originally had done when I was building this 190. Fortunately I was able to recover some of them, including the pictures that show how the aileron linkages were made. The other methods of this design can be referenced by browsing through the P-51 build log. The process was nearly identical. I did run into a snag when I applied the finishing resin over the 5 minute epoxy where there was no glass. My best guess is that I neglected to wipe down the fuselage after I sanded it and the 5 min zap epoxy never fully bonded. The finishing resin pulled most of it up and required a lot of sanding.

Servo Details!

RC FW190 hot wire wing with low cost HXT brand servos

Here is a close up of the servo package showing the tie off and how one servo interfaces with the flaps. Not the cleanest of methods, but it works well and was very cheap.

RC FW190 hot wire wing, push pull servo setup

The orange plastic is some thick plastic I pickup up to try vacuum and form, I haven't tried using it yet, but it works well for other things. Here it's cut into two horns that are hot glued to the inside surface of the flaps.

FW190 Flaps, fully deployed, single servo driven.

The horns are push-pulled via a bent up piece of music wire. We call it music wire, really it's thin gauge spring steel from an online hobby store. There is a stop collar on the end of it to keep it from sliding off. Surprisingly this setup works very well and provides repeatable, ridged, equal movement of the flaps.

Top of the wing view of the RC pull-pull string

Here's the working end of the servo string, from the top of the wing. The string maybe should have been Kevlar, or maybe wire. There was a problem with where the string redirects. Originally these very tiny tubes were held on with hot glue. The hot glue easily melted in the sun and allowed them to let go. Luckily I found this on the ground while I was painting it, before the maiden flight! The tubes were replaced by longer ones held on this time with Gorilla Glue. Additionally, the tube should be behind the tube that goes completely through the wing for a bit more support. The corrected is Gimped in below.

Corrected more secure version of the RC pull-pull string

The bottom of the wing is shown in the following picture. A tube cuts completely through the wing redirecting the sting to the horn.

Bottom of wing view of the RC pull pull string.

I really like this method of moving the control surfaces. It's easy to setup and is slop free. With the servo centered, the sting is run back to the horns, wraped, and then held in place by a spot of hot glue. I only wish I would have made a way of getting to the servo without hacking the plane apart.

A Note on Wing making

Also for those who are planning to hot wire a wing out like I have done on here, please be advised of the following! I have found and have been show by GOK of rcgroups that there is a potential for your wing to warp when you cut it. The reason for this is because the extruded polystyrene foam has internal stress from the manufacturing process. It is if the block of foam is contained in a wrapper that is a tiny bit too small. When you slice off a thin layer from the top the piece will tend to curl towards that wrapper. To correct for this I have done one of two things, unintentionally of course. The first is my flat bottom wings, which use that virgin side, are very thick. This allows the remainder of the foam to counter that internal stress and hold their shape. The other is to cut that virgin surface off both sides, and for structural reasons it helps to maintain thickness. I have noticed this issue when making tail surfaces from 1-1/2 thick foam, the center parts are fine while the parts with virgin sides are warped.

(Must apologize I am appearently very tired at the time of writing). Building the fuselage proved to be pretty challenging on this model. The front four profiles while forming the correct shape, were difficult to get fit correctly. The profile pieces need to be adjusted so that they allow for the correct thickness of the surface material. In the past I've eyeballed the profile, resulting in a somewhat sloppy fit and perhaps a somewhat sloppy shaped fuselage. Also some of these parts look as if they will never make the desired shape. For the record the I currently believe the proper offset for the quarter inch Dow Protection Board III fan fold to be three sixteenths of an inch. I have tried a full eighth but it seemed to result in a part that was too small, not forcing for the surface material to take the proper shape. The plans will be properly adjusted before I post them online in PDF format.

The fuselage shown in the next picture is dry fit. Notice that the motor is not installed, I actually had to cut it apart to get it in. I'm sure I could work this all out so that I could assemble the motor with the plane, but for unknown reasons I force myself to do it this way.

Pink and blue bare version of the FW-190 warbird

Results of my hard work. I feel that they were worth the effort and really showcase what is relatively easily done with computer aided design.

RC conture

Again if the offset would have been done correctly at three sixteenths, this would have went very smoothly. However, it did end up showing me that a doubled bulkhead former is definitely the way to go. Use a bulkhead on each side of each section making somewhat of a cylinder that is completely sealed. Then all you need to do is glue the cylinders together. Much easier then trying to get one piece of quarter inch foam to share with two surface parts.

RC FW190

Next is the initial mounting of the motor with some of the cowl cut off. I will glue that part back on in a later picture. The motor uses a sandwich mount a little bit different then the P51. (Read better, as in improved). In this sandwich mount the entire spongy surface is held into place without a back plate. This ensures that it will not tear away from a back plate on a rough landing. This is how I should have mounted the P-51 motor. The EPP foam is kept from pulling out the front by two factors. Number one is the glue on it's edges. The second is the donut of EPP foam that is glued into place behind a cut away profile, which has been reduced to a slight edge. This has effectively held the motor in place for about 15 flights as of now, and effectively held the motors in place for more then 100 combined flights on my now retired BF-109 and active P-47.

500XTH brushless motor mounted on EPP foam

Here is the fuse all set with Spackle and sanded, ready for glass.

spackled and sanded ready to glass fues

I wish I had more to share on this one, only one thing to do, build another...