Focke-Wulf FW190A

The Focke-Wulf FW-190 was Germany's most lethal fighter of of World War 2. Despite its large radial engine It was also one of the most beautifully proportioned fighters of its time.  The FW190 maintained superiority over the British Spitfire MK V for almost two years because it could out fly its opponent on nearly every count. Approximately 20, 000 Focke-Wulfs were produced and, in various versions, were used as day and night fighters, fighter-bombers and in ground attack roles. Its wide stance under carriage gave it improved ground handling over the BF-109's  With a complement of four 7.92mm machine guns, two or four 20mm cannons, and many equipped to carry four 110lb bombs the FW190s came to be called "Butcher Birds" by the Allies.  _____________________________

Specifications Wingspan 36 Inches Wing Area 220 Square Inches Weight, Ready-to-fly 36.5 ounces Wing Loading 23.9 oz/sqft Battery 7 Cells Sanyo CP1300SCR Motor Jeti Phasor 15/4 brushless ESC Jeti 30 amp brushless for 6-10 cells w/BEC Propeller 8x6 APC thin electric Controls Ailerons, Rudder, Elevator, and Throttle R/C components FMA "Extreme 5" Receiver, Cirrus CS21BB servos for rudder and elevator, Hitec HS85BBMG for retracts, HS81 for ailerons Kit Manufacturers Home Page http://www.picaweb.com

This model is a 1/12 scale version of the 190A based on a kit by Pica. It's a reasonable sport-scale rendition but I felt the need to make many modifications to satisfy my desire for something more authentic looking. The kit's cowl profile is too 'squarish' at the front, and there's no wing root fillet. Many other details were left out which I added to create what you see here
 
 
 
 

The basic kit goes together pretty quickly. The fuselage construction is almost monocoque in structure built up  from a few simple balsa sheets. Then there is a big boxed in cavity for the fuel tank which would  become my battery box. The fuselage is nearly ready for paint. Here it is with 1 layer of 0.5oz Sig glass cloth.
The cowl will get a re-work. I casted a plaster plug into the original kit cowl and then re-shaped it to a more authentic profile. This will serve as a mold for a heat-shrunk soda bottle cowl
I decided to do this one with retracts. I'm using a set of the Robart micro retracts that I had laying around.
The gear linkage used a trimmed down 1/2A CL bellcrank piece.

First flight results
Originally I designed the 190 to use a Multiplex Permax Turbo 450 motor with 2:1 gearing and 10 cells. This combo turned out disappointing I got the FW190 almost finished and test flew it. It was all done except for the final paint and a few details. The flight didn't go so well though. The plane weighed in at a very porky 42.5oz which with only 220 squares puts it at 27.8oz/sqft. Power was estimated at about 185 watts for 70W/lb.   It turned out to be quite tail heavy and even after adding 1oz lead to the nose the CG was still a bit aft. The battery already extends forward through the firewall. I decided to give it a try anyway

The first flight was, as expected, quite squirrely. I almost stalled it a couple times and was rewarded with a bit of a snap to remind me of the poor CG and high wing loading. It was ROG from the paved strip for takeoff then a couple circuits before retracting the gear. The speed was very nice and as long as I kept the speed up and didn't try any sudden maneuvers it was manageable. It actually had a pretty hot climb rate once on-step. I was able to make a couple of low level high speed passes pulling up at the end of the runway. It looked great blasting by with the gear tucked up. Then I landed it after about 3 minutes. I lowered the gear on the downwind leg and eased it around on final. It came in hot but with a very easy to control sink rate and greased the landing.

I tried once more after adding another 1/2 oz of lead to the nose. This time I did stall it on take off and put it into the weeds from about 20 feet up. The damage was substantial but easily repaired.

Back to the drawing board
I had to give this some serious thought about trying to lighten it up without sacrificing power. First to go was the lead in the nose. I would shift the battery even more forward. It ended up going halfway into the cowling. A lighter receiver was also chosen; the FMA Extreme 5.  The 10 cell CP1300 pack had to be downgraded to a 7cell pack which is about 3.75oz lighter. Finally, I had to go brushless with it. The Jeti 15/4 was chosen due to its high power output in a direct drive application at a light weight. After all this I got it back down to a 'spritely' light weight of 36.5oz. The plane's spec weight under glow power is 36-38 oz so I think I did pretty good.

Success!
I flew the FW190 again Sunday on the new power system. It was the Jeti 15/4 with 7 cells of CP1300. Total weight this time was down to 36.5oz. , within the specified glow powered weight. The proper CG was achieved this time. Even with all the juggling of components it was still necessary to use a heavy prop adapter with a couple steel washers for good measure to get the balance correct.

The flights this time were MUCH better. It tracked down the runway nicely but used up at least 150 feet till it got up enough speed to lift off. Flights were smooth and FAST! It still reminds of its high wing loading with a bit of a wallowing stall if flown level at less than half throttle. Turns require the speed to be kept up and the application of additional throttle. This thing covers a lot of distance quickly. Because of the location of trees at one end of our field I decided to land it downwind the first time for fear of dropping it into the trees. It came in hot and went the full length of the runway then bounced and continued on into the cut grass past the end. It ended up flipping when the wheels finally dug into the grass and broke the 8x6 APC e-prop.

The next two flights were with an Aeronaut 8.5x7 prop slightly trimmed to 8 inches. It flew faster this time. I'd have to estimate about 65MPH+ based on Motocalc predictions and best guess based on visual observation. Downwind runs seemed even faster. I still have to determine flight times capable with the 1300 packs. I'm guessing on about 4 minutes but I was keeping them to about 3 minutes just to not take chances. The plane takes a lot of concentration to fly and even with 75% expo on the controls it takes a delicate touch. It looks awesome blasting by on high speed passes but it goes by too quickly to get a very long look at it. I wouldn't recommend this plane to anyone with less than advanced flying skills and I think I only barely qualify.