SeamusG

<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

SeamusG

Just a note concerning the AL60 engine mount. The mounting holes are square. While measuring / drilling the holes in the FW for the mount it became apparent that the mount can be bolted upright, canted 90 degrees left or right or inverted yet keeping the thrust line of the engine in the "right" place. The only thing that changes is the spray bar location and the throttle location.

TTFN,

SeamusG

I just spent some quality time with my wood. I busted up all of the laser cut & die cut pieces. I really, really, really appreciate laser cut wood. After separating all of the wing ribs I wanted to clean up the "holes" which were pretty sloppy. I created 2 bundles of ribs, each tied together with a couple of rubber bands. I then aligned them by inserting 1/2" stock in the main spar slots. The Dremel with a sanding drum was used to clean up the holes in a single swipe. Turned out pretty well. Oh, btw, MA - I busted off 2 standoffs clean off and cracked 4 others requiring a bit of CA.

I'm going to refer to the manual steps as I go. Keeps me aware of where I'm at.

Step 1 - align the engine mount to the firewall, drill the holes and epoxy the 6-32 blind nuts. I clamped the mount to FW and scribed to location of the holes. I then removed the mount and drilled the holes in various stages to the necessary size for the blind nuts to ensure that the mount bolt holes were aligned properly. The mount was bolted to the FW with the blind nuts loosely fit. The 6-32 bolts were tightened to draw the blind nuts about 1/2 the way in. 30 minute epoxy was applied under the blind nuts and the bolts were tightened to fully set the nuts. I used a bunch of q-tips to clean off all the excess epoxy to ensure that the F-1A former would sit flush against the back of the FW.

Note - I am not going to glue F-1A to the FW because it will be used as the leading edge of the tank hatch. If I change my mind on this I can still glue it up. I am also not going to worry about mounting the engine to the mount until I fit the cowl.

pic 1 - 2: wing rib bundles
pic 3 - 5: FW and blind nuts

TTFN,

chashint

I will be following your progress, looks like you have a good plan.
What are you going to cover it with ?

r2champion

You better stay on it, or I will be calling you out on it....just ask MasterAlex! [8D]

Seriuosly though, I will be watching along and best of luck. I will be building my second Hog soon.

Best of Luck!

SeamusG

Charlie - I'm using Ultracote colors true red, bright yellow, blue pearl, and white. Lotta colors and easy to work with. Just won't activate with Windex. The cowl, LG and wheel pants will be painted using Rust-o-leum "painter's choice" apple red gloss covered with clear as it is very close to Ultracote true red.

dragonov3

My Feedback: (3)

Just so ya know, there are people that do not post often but watch these threads closely. I am one of those people (shy i guess). Keep up the good work.
I am building a GP ultimate bipe .40 right now. May have to do a hog bipe next. Love the lines of the hog.

SeamusG

Step 1 cont.

This plane may be used with floats. To help ensure that the inside of the fuse stays dry the hole in the FW is filled with a putty made of 2-part Finishing Resin & micro-balloons. Sized holes for throttle and fuel lines will be drilled later. Oh, the AL60 engine mount has a cross member that nearly covers the hole requiring a relocation of the fuel lines.

Building note: I like to develop a saturated putty of resin and micro-balloons for each of the 2-parts. After making the 2 globs I mix them together to ensure that I have plenty of time to work with them before the mixture sets up. I keep a glob of unused putty when I’m away from the model so that I can monitor how the drying of the epoxy is progressing. When it gets to the consistency of cold cookie dough I will trim the area filled with a razor blade or Xacto knife to keep sanding to a minimum.

I created a solid (aka no stringer notches) version of F1A and epoxied it to the back of the FW.

Step 2 - F-5A is epoxied to F-5.

Building Note: When gluing wood I position the softer stuff proud of the harder stuff so that when sanding for sheeting or covering I sand soft balsa rather than hard lite ply. This applies especially for wing ribs & spars too. Also, when using epoxy I trace the outlines of the smaller component on the bigger one. I use a craft painter’s spatula to apply the epoxy within the lines – a very thin and consistent application. Once the pieces are positioned and clamped / pinned / weighted I use a cotton swab soaked in alcohol to clean all perimeter joints of spooged out epoxy to minimize sanding issues, ensure good fitment and improve cosmetic looks.

Step 3 – Fit 6-32 blind nuts to the LG plate. To fit the Dubro LG I created a new LG plate to size. I located, drilled and fitted 4 6-32 blind nuts that align with the predrilled holes of the LG.

Step 4 – F-3B is epoxied to F-3.

Building Note: The instructions suggest aligning the pieces with a drill bit. I had a couple of ¼� dowel pieces that I inserted in the holes before clamping the pieces. Once clamped, the pieces were removed and all glue boundary surfaces were cleaned with a cotton swab soaked in alcohol.

Step 5 – Epoxy fuse sides & doublers.

Building Note: The doubler was carefully positioned on the fuse side and nailed to the board using 8d spikes. I traced the outline of the doubler. I positioned the new larger LG plate on the doubler and marked the doubler for cutting. The doublers were cut and sanded for the new LG plate. I put a thin coat of 30 minute epoxy inside the tracing lines. The doublers were re-positioned using the alignment holes. All exposed glue joints were cleaned with a cotton swab saturated in alcohol. The doublers were then weighted.

TTFN,

Minnreefer

Looks good, I did ny see, are you going to be moving the landing gear forward? You also mentioned that you may put floats on this, are you going to modify it for floats now, or wait and see if you add floats.

Looks great

Jon

SeamusG

Too many comments on the "downside" of moving LG forward so I'm leaving it in the hands of SIG's designers to have gotten it pretty close. I'm gonna have to learn to land her smoothly.

On float preparation, I will add a rear LG plate behind F-5 made of 1/4" ply with a couple of 6-32 blind nuts.

<edit> Hey, why not use the original LG plate? See pics. I used a chisel technique that Norm Abrahms would be proud of.

TTFN,

*JCB*

My Feedback: (9)

There really isn't a need to move the gear forward. My hog was built stock and i nosed it over once. It was on my second flight, i just hammered the throttle too hard on takeoff and it just buzzed the prop on the ground a bit. I haven't had a problem since

Just build the plane as-is. Sig did a great job with it!

SeamusG

Bummer alert. The SIG Sun Dancer cowl does not fit. I know that some have used the AeroFiberTech cowl (S-58). What other cowls have been successfully used on the Hog Bipe?

Tia

SeamusG

Sidebar step: Cowl preparation.

This assembly was completed before post 12 but I decided to include it anyhow – a flashback post.

The cowl is now assembled so that necessary adjustments can be made to the firewall area. The cowl is a SIG Sun Dancer cowl. The kit included the 2 halves and 2 lengths of ABS strips about 1/64 x ½. No instructions.

As there were no instructions I noticed that the cowl material is the same as that of the wheel pants, so I used the wheel pant assembly as a guide. I taped the halves together with good old Scotch tape a while back. Bad move – this stuff is a bear to remove. I tacked several points using thin CA. Of course, it bled through the seam onto the back of the tape and my fingers. I applied thick CA to the seam and added several “tack strips� of the ABS strips. The ABS material is too smooth for a good bite. I then sanded the cowl’s seam and one side of the ABS tape. Thick CA worked out fine.

To reinforce the seam I pulled out some 2� fiberglass tape and cut pieces to length. I applied 3M 77 spray adhesive to one side of the tape and applied the pieces to the seam. 3M 77 allows the tape to be positioned easily and it stays put in the very convoluted surfaces inside the cowl. I then mixed up some 30 minute epoxy and put a light butter coat on the tape. A heat gun was used to flow the epoxy being very careful not to overheat the ABS material.

After drying, the entire surface of the cowl was sanded to provide bit for primer, surface filler, and then paint.

The nose of the cowl was then opened up to accept the engine crank / prop backing plate with a drum sanding attachment on the Dremel.

The cowl / engine mount / firewall fitment was tested. Oops. The thrust line of the firewall / mount / engine did NOT align with the cowl’s front opening. If the thrust line is aligned with the cowl’s opening the cowl will not align with the firewall or fuse.

Guess I will share this with SIG’s engineer that gave me the “thumbs up� on using the Sun Dancer cowl with a Hog Bipe.

TTFN

SeamusG

Step 5 (completion)

Firewall leading edge base was beveled to conform to the angle of the fuse & doubler.

Building Note: a good quality sanding block like Great Planes Easy-Touch sanding bar with 80 grip paper makes this a breeze. I have used home grown sanding blocks made of hard balsa with 80 grit paper. The ¼� ply is very hard and will deform the balsa block.

P-4 cabane mount supports were positioned, glued & clamped.

Building Note: the supports need to be set back 1/8� from the edge of the fuse top. A couple of pieces of kit trash 1/8� lite ply and clamps made for a nice set back jig. Be careful to clean up the wet glue on the inside of the support to allow the cabane mount blocks B-3 to seat nicely on the fuse surface. I used 30 minute epoxy and cleaned up with an alcohol-saturated cotton swab.

B-3 cabane mounting blocks were positioned, glued & clamped.

Building Note: I was very careful when buttering the back of the mounting blocks with 30 minute epoxy. I was careful to only apply epoxy to the outboard edge of the backside of the blocks. When clamped the epoxy will be forced toward the cabane slot but not enough to ooze into the slot.

4-40 cabane mount blind nuts located and glued.

Building Note: I do not want to shock the glue joint between the B-3 mounting block and the fuse by tapping the 4-40 blind nuts in place with a hammer. I pulled the nuts in place with a “throw away� 4-40 bolt from the fuse side. Be sure to us a sacrificial piece of wood between the head of the bolt and the fuse side.

TTFN

SeamusG

Step 6: Tail wheel mount (TWM)

A new longer TWM was fabricated because the Sullivan TW is longer than the SIG hardware. Scrap 1/8� lite ply from kit waste was used. The Sullivan unit uses 4-40 bolts with blind nuts rather than machine screws.

Building Notes: I marked the TWM mounting hole locations by aligning the pivot point of the TW assembly with the trailing edge of the TWM. 1/8� pilot holes were drilled. The pilot hole locations were transferred to the FBR. The TWM guide holes were expanded to 9/16� to accept 4-40 blind nuts. The FBR holes were expanded to 7/16�. The blind nuts were glued to the TWM with 30 minute epoxy. I used the SIG 4-40 bolts and a hammer to seat the blind nuts. The TWM was glued to the FBR with 30 minute epoxy. Before clamping I inserted the SIG 4-40 bolts thru the FBR and into the blind nuts to ensure correct alignment when clamped. After clamping the bolts were removed. When dry I will run a 4-40 tap through each blind nut to ensure that there is no epoxy buildup.

TTFN

SeamusG

Pre-fuse construction preparation

Building Note: If you are going for a quality build, it’s time to a little pre-assembly preparation.

• Tops of both P-4/B-3 blocks on a side are sanded to ensure that the tops of both are aligned, smooth and true with the edge of the fuse.
• All exposed glued joints of the fuse and doubler are sanded.
• All laser-cut attachment “nipples� are sanded off.
• The inside of the cowl cheeks are sanded smooth because after assembly you cannot effectively finish these surfaces.
• Inside surfaces of the fuse and doubler are sanded (OK, I’m anal on this – just in case I go with transparent covering)
• Edge surfaces of F-1 and F-3 are sanded to eliminate any “nipples� (just being redundant)
• All pin holes created when aligning the fuse & doubler are filled with a finishing resin / micro-balloons putty
• Test fit the cabanes with the mounting blocks.

<edited> I installed the 4-40 blind nuts after the fuse sides had been attached to F-1 and F-3. Note the use of a piece of 1/8" lite ply used to protect the exterior surface of the fuse side when drawing the blind nut tight with the screw.

TTFN

SeamusG

Fuse Construction

Step 7a: Install FW F-1 and former F-3

Position and epoxy F-1 and F-3 onto 1 fuse side.

Building Note: I used 30 minute epoxy for both. There is slop in the doubler F-1 slots. Make sure that when gluing F-1 force it to either the front OR the rear on both sides. I used flat toothpicks on the backside to ensure that there was little or no gap on the front where the gap will be exposed to fuel and exhaust spooge. I cleaned all of the joints with alcohol-dampened cotton swabs. I checked their alignment several times. I’ll recheck the alignment in 15 minutes to make sure nothing changes.

TTFN

*JCB*

My Feedback: (9)

Here are two cowls that fiberglass specialties has for the Hog. I don't have any personal experience with them, but i hear they do good work.

SeamusG

Fuse Construction

Step 7b: Install other fuse side

Position and epoxy other fuse side onto 1st fuse side.

Building Note: Even though F-1 and F-3 are square to the 1st side, make sure that they are at 90 degrees to the 2nd. After applying epoxy and joining the 2 sides I had to add pressure on the front of the 2nd fuse to “push� the 2nd side back to ensure that F-1 and F-3 are at exactly 90 degrees. Again, I used flat toothpicks on the backside of F-1 to ensure that there was little or no gap on the front. I cleaned all of the joints with alcohol-dampened cotton swabs. I checked their alignment several times. I’ll recheck the alignment in 15 minutes to make sure nothing changes.

TTFN

SeamusG

Thanks JCB - gotta think about how a round cowl would look. [sm=50_50.gif]

*JCB*

My Feedback: (9)

ya, the round cowl isn't my cup of tea either!

Here are some pics from [link=http://www.fubarhill.com]www.fubarhill.com[/link] . There are a few round ones in there and i believe the black cowl is the other cowl from fiberglass specialties. The other cowls are various other ones... Go check out the site for some ideas.

SeamusG

Thank ya, thank ya!

SeamusG

Man, they have some seriously sweet Hog Bipes on the Fubarhill site!

Gotta rethink the use of a cowl.

MasterAlex

What's this??!! Hey this is great stuff SeamusG. Very impressive. The race is on!

Seriously, I look forward to watching the goodness.

-MA

av8djc

My Feedback: (4)

I think the one on the right is what I used on mine 5 (?) years ago. I don't remember buying it but might have. Do you know what kit it came from?

Dave