A couple of years ago, I built a House of Balsa P-47 for electric use. Flying the airplane with a long can 400 with an 8 cell 600 AE pack was OK, but nothing to write home about. The airframe was solid with very good flight characteristics, but lacked a little on power and a lot on duration. With improvements in motors and batteries, I though it would be a good time to revisit this group of airplanes that House of Balsa has been manufacturing since the beginning of time. (...what I heard from the old timers.)
House of Balsa has produced these 1/12 sport standoff scale airplanes for use with .049 to .061 gas engines for a very long time. They have the FW190, the 109, P-47, and P-51 available, and all are similar in size and weight. The kits are die cut and include all the wood with a hardware pack, decals, instruction book, and plan set. The instruction book contains photos of each step, which make construction easy to follow.
These kits are also very reasonably priced. The wood is not quite as light as some other kits I have built, but not bad. I built a kit from another manufacture a few months ago, and the wood was lighter. In fact, it was so light, I broke about a third of the parts just building the airframe. I fly most of my war birds on grass that is usually too deep for landing gear, so this airplane will be built without landing gear for bungee launch, like the rest of my fleet. For those that have not built many kits, I will follow the order in the instruction book in this review as much as possible so that you may use both for reference.
Building the fuselage
Start by laying out the fuselage side pieces. Make sure you have a right and left side when you glue on the forward doubler and the center light ply pieces. We will save most of our weight when building the fuselage. This light ply is needed around the wing area for strength; however, it may be more that we will need for an electric airplane. Feel free to cut holes in this area to lighten the sides. Place the fuselage top crutch on the plans and mark the bulkhead positions. Glue bulkheads number four and five into position. Glue the prepared fuselage sides to the top crutch, and join the rear fuselage sides together. The firewall is quite thick and most of this wood is not needed. Cut out the center before gluing into the fuselage. You are now ready to add the 1/8" square support to the fuselage bottom front and rear. Glue in the screw hold down plate under the 1/8" square stock. Skip the next sections on the tail wheel. For bungee launch, it's not needed. Glue in the triangle stock in the front of the fuselage. Most of this will be sanded away when you round off the nose of the airplane. Glue the front two cowl opening rings together and add a standard 400 light ply motor mount to these pieces. The light ply motor mount and a couple pieces if 1/64" light ply for the fillets are the only wood not in the gas kit that I needed for electric conversion. Once the motor mount is in place, glue the cowl rings to the front of the fuselage. Down thrust is already built in.
The next step is building the bottom hatch. This hatch will come in handy when charging you battery. You will have enough access to charge the battery without removing the battery from the airplane if you wish. Mark and glue the ply hold down plate to the hatch block. Put the bottom hatch onto the fuselage and drill a 1/8" hole through the hatch block and both hatch plates. Epoxy a 4/40 bind nut on the inside of the fuselage holding plate. Enlarge the hole in the hatch base with out going through the hold down plate to accommodate a washer and bolt. Glue the outside doublers in place on the fuselage sides. A pre-shaped balsa block is glued on the top of the fuselage. Cut the inside of this block out before gluing it down. This is another good place to save a little weight.
Set the top structure base deck on the plans and mark all the canopy parts. Tack glue the 1/4" square stock to the bottom of the base deck. This will come off later. This is used only to aid in gluing down the plastic canopy in a couple of steps. Glue the instrument parts and the headrest onto the top structure. Included in the kit is a thick paper sheet that contains a cutout section for the canopy, instrument panel, and several templates for other parts of the airplane. These are a nice aid in building this airplane. Now is the time to paint this section prior to adding the plastic canopy top. If you want to add a pilot, now is the time. I use liquid mask to cover the top of the canopy. I find it much easier than masking. Lightly sand the inside base of the canopy top in order to scuff the plastic canopy prior to gluing it to the top structure. The 1/4 stock you tacked glued earlier will allow you to pin down the canopy top to the table while gluing it to the top base.
Once the canopy top is dried, pull off the 1/4" building crutches, and trim the plastic canopy to match the base plate. Glue the assembly to the top of the fuselage. With the bottom hatch in place, you can now sand the entire front of the fuselage to shape. There is a paper template for contouring the front of the nose. Cutout and shape the cowl bumps and glue to the sides after you have completed the sanding of the nose.
Lay a piece of wax paper down on the wing portion of the plans. You build the wing directly on the plans to ensure it is straight. You can also build both sides at the same tine if you wish. Pin down the bottom leading and trailing edge sheeting. Glue a piece of 1/8" square onto the back edge of the leading sheet. You will now set ribs two through nine on the spar and the sheeting. Only glue the ribs to the trailing sheeting at this time. You will need to bend the leading edge sheeting up before gluing later. Glue the top 1/8" top spar in place. Add the 1/16 X 1/4" leading edge along with the 1/8" square trailing edge. Add the 1/16" top trailing edge sheeting. You can now glue the bottom leading edge sheeting to the leading edge and spars. Next, add the top leading edge sheeting.
Glue in the angle guides for correct dihedral. You may want to lay these pieces on the plans for reference to ensure you have them the right direction prior to gluing. Add the angle guides and glue in the number one ribs. Glue on the 1/4" X 3/8" leading edge. Sand the interior surfaces of both wing pieces to ensure a smooth bond. Epoxy the two wing halves together with a total of three inches of dihedral.
Using the plans as a guide cut the inboard trailing edges from the trailing edge stock. Grove the forward edge and install the aileron linkage. The linkage pieces are different lengths. Make sure you get them in the correct side. The linkage is pre-bent and easy to install. You may want to put a small amount of oil in each end of the brass bearings on the linkage to ensure you don't get glue in them. Glue the trailing edge assemblies to the wing. Add inboard leading edge fillets and sand the leading edge. A sample of the edge contour is shown on the plans. Cut out wing tips from supplied blocks using the provided templates, glue them onto wing, and sand them to shape. Using reaming aileron stock, make ailerons and sand them to shape.
Prior to covering, fit the wing to fuselage and sand as necessary for fit. The wing will attach to the fuselage by adding a 1/8" dowel to the front and by drilling and mounting a bind nut in the rear. There are heavy paper templates for the wing fillets. I used 1/64" ply instead. I thought this might be more durable if I took the wing off very much. To build the fillets, first place a piece of wax paper between the wing and the fuselage. Slide the fillet base in place on top of the wax paper. This will keep the fillets from sticking to the wing as you build them. I used light filler to form the fillets. When dry, sand and seal to get a good paint finish.
Since I plan to bungee launch this airplane, I decided not to add a functioning rudder. If you choose to go this route, just glue the rudder pieces together and cover. The elevator is joined with 1/8" dowel, and then the edges are sanded and covered.
I used Ultracote Light Clear to cover this airplane. I wanted to keep it light as possible since was planning to paint the entire plane. The covering job is pretty straightforward. One caution to the builder should be mentioned. When covering next to the plastic canopy top, do not use too hot of an iron on the plastic or it will warp.
I like to use Model Master Acryl for painting. I lightly scuffed the surface to be painted to promote adhesion for the paint. These acrylics are fast drying, easy to clean up, and come in a large selection of colors. Prior to painting, make sure you have added an air intake hole in the nose and an exit hole in the bottom of the fuselage. I can paint an entire airplane in an evening with little mess using acrylic paints.
Installation of gear
The Mega motor will bolt directly to the Speed 400 light ply mount, and there is ample room in the nose for the motor.
You will need to add a sheet of scrap under former four with Velcro to hold the battery. I used two servos; one is for the ailerons and one is for the elevator. There is ample room for a rudder servo if you decide to add a working rudder to the plane.
There is plenty of room in the fuselage for receiver and speed controller. I put the receiver directly in front of the elevator servo. Control throws were set as recommended in the instruction book at 3/16" ailerons and the same for elevator.
The House of Balsa FW190 is a sweet airplane to fly. The first flight was fast with plenty of power with an 8X6 prop. It seemed I had the CG slightly forward, so the first flight ended early at about five minutes. After adjusting the CG slightly, the 1100mAh NiMH pack was recharged, and the plane was ready to go. This pack, from Wattage, has been highly touted on a couple of threads on E-Zone. It was great. The FW190 flew very fast and very stable. Outside loops were even possible. The rolls were smooth, and I just did not see any bad flying traits from this airplane. To check for duration, the airplane was flown to BEC cutoff. I usually don't run an airplane down to empty in case I need another pass for landing, but I wanted to get a good estimate of duration with this motor and battery pack. A full nine minutes of flying was achieved on the setup. I was thrilled. It is a great flying war bird, with more power than before, and more than double the duration of my old P-47.
The House of Balsa FW190, with one of the new electric power systems available today, makes a great flying electric war bird. The kits are straightforward to build, easy on the pocketbook, look great in the air, and are great flyers. I'm sure these were good gas flyers, and that is probably why they have been around for so many years, which is lucky for us electric flyers. I have heard of other electric conversions from this series of airplanes where the builders are replacing pieces with lighter wood. I really don't think it's necessary with the new motors we have available. Save weight were practicable, build it, and go have fun. I have already started the P-51, and will be building them all I'm sure. All I need now is for HOB to add a spitfire and a Zero to this collection and I'll be set.
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