<edited 2/20/2009> Kit Disclaimer: If you are not comfortable with building or do not want to learn how to build a kit with a significant amount of structurally unsupported 1/16 balsa sheeting you should consider building a different kit. To my regret I am neither but it's too late for me 'cause I'm too far into the build.

MasterAlex “shamed” me into doing a build thread. No - not really, but it makes for good press.

I wanted a biplane in my fleet. I originally purchased a Goldberg Ultimate biplane kit from my LHS. Then I started reading the build threads on bipes. Somewhere along the line I found that the SIG Hog Bipe was what I really wanted so back to the LHS I went and exchanged the Ultimate for an HB kit.

Background - I’ve been involved in this hobby for a year and a half. I’ve built 2 SIG 4Star60’s, 1 ½ SIG SSE, a SIG Kadet Senior and an AirScharnel Avenger B2 combat plane (since sold). I’m a proficient intermediate flier that wants to develop some decent pattern flying skills. I’m not too keen on 3D but I do have a Hanger 9 ShowTime 50 from eBay that will get flown when my skills improve.

Back to the HB build. I believe in knowing the end-state of a project before jumping in. I’ve read many build threads including both HookedOnRC’s and MasterAlex’s Hog Bipe build threads to become familiar with the project and figure out what modifications, if any, I will include. I scanned the SIG manual side and top image of the HB in preparation for developing a covering scheme using Visio. All of the wood has been inventoried and replacement pieces have been ordered and received from SIG.
Here’s the component / modification list I came up with:

• Cowl - SIG’s Sun Dancer cowl (SIG measured the firewall for the HB and Sun Dancer and they are the same so it only made sense). Only time will tell.
• LG - Dubro Super Strength LG for .35 to .61 planes #789 (I’ve used it on both 4Star60s and have 1 in stock). The mount is predrilled for 4 6-32 bolts at the corners where as the SIG unit has 3 6-32 holes in line across the center. It is also 3/8” wider than the SIG unit. This will require cutting a new larger ¼” ply LG plate with 4 blind nuts and extending the tri-stock reinforcing pieces.
• Engine mount - Hayes AL60 engine mount mounted 90 degrees to the starboard side. It provides flexibility in the drive train while using the same bolt pattern. I can mount an OS61FX, OS75AX, OS91FX, Super Tigre G90, Saito 91 and more using the same mount. I will install 2 throttle cable tubes – 1 for a 2-stroke and 1 for a 4-stroke). Also the mount gives plenty of meat to tap the holes for 6-32 x 1” hex head bolts with no need for nuts on the underside.
• Fuel tank - Dubro 14 oz fuel tank cat. #414. The profile of this unit is identical to the profile used in the HB plans. Also, I have 1 in stock.
• Tank hatch - I’m planning a tank hatch similar to the one MasterAlex fabricated in his build using a couple of 1/8” dowels to locate the front and a couple of super magnets in the rear for a screw-less installation. I’m also relocating the tank floor. With a vertically-mounted OS91FX using the AL60 mount the spray bar is ½” above the tank’s center line. When rotated the carb spray bar will be 5/8” below the tank’s center line. The difference is 1 1/8”. If I am to use SIG’s tank center line location as “optimal” then it follows that I need to drop the tank and tank floor 1 1/8”. I will do more research on this before committing to an approach.
• Tail wheel - Sullivan Tail Wheel Bracket (no. S860). I need a 1” tail wheel. I’ll solder washers on the axle to retail the tail wheel.
• Rx –Spektrum AR6200
• Battery – 6.0 v. 1400 mAh NiMh (got one in stock)
• Servos – Throttle JR ST47 std., 2 Aileron, 1 rudder and 1 elevator Spektrum DS821 digitals.
• Switch – MPI heavy duty charge / switch combination.
• Control rods – throttle - Sullivan cable with quick connects, ailerons – 4-40 wire with solder & threaded clevises, rudder – Dave Brown fiberglass pushrods or Sullivan gold-n-rod or 2-56 pull-pull, elevator – Dave Brown pushrods or Sullivan gold-n-rod.
• Wheels – 3” of some type.
• Dubro nylon hinges will replace the CA hinges.

It’s time to carve up the plans. I went ahead and sliced up the plans. Since I’m making modifications to SIG’s approach I decided to modify the plans incorporating my updates.

• Dual aileron servo - I recalled that the separate plans are NOT in scale with the original plans and if you use them to cut stock the stock will end up short. I took the separate servo plans and incorporated them onto the original plans using a Sharpie. I covered up any reference to the single servo approach. Hey, I confuse easy. I added the servo wire tubes on the lower wings. I added horn locations on the lower ailerons and added 4-40 control wires between the servo and the ailerons.
• I used a highlighter on any reference to the fabricated parts from SIG.
• I added 4-40 blind nut images on the TWM (tail wheel mount) for the Sullivan tail wheel.
• I removed the original LG blind nuts and added the 4 6-32 blind nut images for the LG. I also increased the size of the LG plate to accommodate the Dubro LG.
• I cut the upper wing tip images and taped them to the upper wing.
• I added a reference line for the fuel tank center line.
• I added the tank hatch to the side and top views of the fuse.
• Using Dubro nylon hinges instead of CA hinges requires moving the bottom rudder hinge location away from the rudder horn install location.

While cutting up the plans a covering approach came to mind. So it was to the computer and Visio. Find the results in the pictures.
Pic 1 – Sullivan tail wheel
Pic 2 – Hayes AL60 mount
Pic 3 – Dubro LG
Pic 4 – positioning of Dubro 14 oz tank
Pic 5 – positioning of Dubro 14 oz tank
Pic 6 – lower wing with dual servo mods
Pic 7 – fuse with tank profile & LG blind nuts
Pic 8 – tail wheel blind nuts & relocation of bottom hinge
Pic 9 – tank center line & LG plate mods
Pic 10 – planned covering bottom
Pic 11 – planned covering side
Pic 12 – planned covering top