"Brodaks Legacy"
Thanks to EricV for having the foresite to save this post, and sendig it to me.
Thanks Len, for supplying this new forum for we, the end users of products, to voice our fair opinions on products and services available to us. I am re-posting a review of Brodaks Legacy that was originally posted to RC-online. A site, aparently not used by us much any longer.
I have been asked by some to do this as they felt there was some merit in the work. At the beginning of the post there is a numerical listing and comments, The body includes a legnthy comment section regarding the building process. It's my hope that by outlining how, and what construction techniques were used, that others will learn new, to them, methods, or share their own methods to achieve the same or better results. In the end, we can all benifit.
Brodak Legacy Kit Instructions: (1-5 - 5 is best)
4.5 As per Brodaks usual instruction booklets. Pretty complete, very minor last minute variations not covered, but for all intents and purposes excellent. Plans are complete, and the attempt has been made to show all the parts.
Materials & Packaging: (1-5)
4.5 Shrink wrapped box, colorful art work, and the wood quality is about as good as I might have hand picked, at least in the example I have. Mine was an early kit and has the problem with the missing washer for the suspended bellcrank. A very minor problem, and easy to fix.
Ease of Build & Finish: (1-5)
5.0 Just started build, Seems straight forward. I will be commenting on the build as it progresses.
Design & Appearance: (1-5)
4.5 The design is straight forward, attractive, no frills. It's ready to do the job with out the distractions of unnecessary complications.
General Flight Characteristics: (1-5)
5.0 Those I've seen fly have been very good. I'll comment more about it when I get to that part.
Performance Capabilities1-5)
5.0 This design is able to slug it out with the best. Pilot skill is the deternining factor here.
Maintenance & Repair1-5)
4.5 As per most full fuselage designs, no surprizes.
Comments:
This design is a continuation, or next step from the designers' Buccaneer series. Some areas for improvement were realized in this plane. It should build lighter than it's predessor due to the built up wing.
It's designed to use either the standard large sized 4-2-4 style engines, or the tuned pipe setups currently in vogue. It can also handle the 4 stroke engines with minor alterations, such as shortening the nose about 1 to 1.5 inches, watch that you have enough space for the fuel tank adequate for the engine.
For the price, (I paid $110.00 at my local hobby shop) I believe this plane is the best value in a competition stunter on the market today. It comes with a special flap horn designed especially for this plane. It'll give you symetrical control response if set up as the plans show.
The disclosure: I worked closely with the designer, Allen Brickhaus, a friend of many years, as I drew the plans. I may be considered by some as slightly biased, but I believe I am being fair with my assessment. I've also been building and flying CL stunters, Sport, and RC power and soaring planes for nearly 50 years. I am mostly a scratch builder, and approach my building projects from that perception. I also have been a profesional model builder for a portion of my modeling career, building engineering models for industry.
Build Tips: See comments as build progresses
Setup Tips: Same as above.
Power Tips:
I would consider the smallest acceptable engine and power to be equal to the ST .46. Modern power plants such as the OS LA .46 should be fine, if the weight is kept within reason. Many fine engines are available, both standard and piped for this airframe. The benchmark for a standard 4-2-4 engine would be the ST .60, for a piped setup, the RO-Jett, PA, or OS 40 or 46 vf would work fine. For 4 stroke power, I would recommend the Saito .56 or .72.
Part 1,
Starting the build. After opening the box, and inspecting the contents, several things impressed me. Brodak seems to have made the effort to put out a quality package here. The wood selection was very good. Obvious care was taken to select the right grade of wood for the use, in almost all cases. Individul sealed bags hold some of the sub-assemblies, and parts, making them easier to keep track of, and together, until needed.
I would have liked to seen laser or CNC pin routering cutting for the parts, but, then I would have had to pay a lot more for the kit. As it is, the die cutting, in all but a few cases, was crisp and almost, fall out in your hand. Especially if I sanded the backside of the sheet first, as suggested in the instruction booklet.
Two problem areas with the die cutting. Plywood, and thicker sheets of balsa. Unless Brodak choses to use lite ply, which I would not like, there may always be a problem with die cutting better grades of plywood. It was a major help to sand the backsides, but I had to use my no. 11 blade in several places. To me, not really a problem. For others be prepared.
The problem with the thicker balsa die cutting is frustrating because I understand why the problem is happening. Brodak is trying to supply decent weights of wood in their kits. Unfortunatly, this means that the thicker pieces won't cut as cleanly as heavier, less suitable wood. I'll take the small inconveninece of some minor crushing, and keep the lighter wood.
Total time for removing all the die cut parts, cleaning them up with sand paper, and labeling them, as per the instructions, 1 hour.
I waited a week before starting the wing construction. I wanted to think out my construction methods. I have, as many know, a pretty neat wing jig based on the Aero 95th. Squadron's jig fixtures.
Normally, the ribs would have to be notched a-la Lincoln Log method to use this jig. I wanted to use the standard rib as it comes out of the sheet. What I came up with, with input from others, allows me to use the jig without any changes to the ribs. I needed to make something that will hold and align the diagonally placed 1/4," sq leading edge. I picked up a piece of 1/2"sq. poplar from my local Lowes.
Poplar is a neat wood, it's a hard wood, but the softest of them. Just hard enough for my use. I have a router table. Without one, this next part might be a bit difficult. I used a 45 degree veining style bit. Make sure the angle is 45 degrees, there are some on the market that are more and you wont get the 90 degrees total that will capture your leading edge.
I set the router table so that it cut ~3/16" deep, and spaced the fence so that the cut was a little off center. I did this so that I could visually see the proper orientation when setting the resulting smaller blocks in the jig.
I started out with a 2 foot section, grooved, then cut off in 1.5" sections on the band saw, resulting in a life time supply of the things. After levelling the jig pieces, I slip a small rubber band over the post. When the 1/4,"sq. leading edge is placed, the rubber band is used to loop around the L.E. and over the top of the post. This holds it securely.
The wing construction with the jig I'm using differs from the manuals levelling bar method. I stripped two pieces of 3/8" balsa 9/16" wide. I know this is an odd ball size, but if you look at the plans,and booklet, you'll see that a strip is added to the standard 3/8"sq stock used for the internally shaped trailing edge. It's needed to match the thickness to the trailing edge of the airfoil. I used a skarf joint and a straight edge and glued them end to end.
Using the rod method of shaping and sanding, I preshaped the trailing edge. Normally I would use a 3/8" dia. rod, and a 3/15," dia. rod to shape the first side. On a test piece, I found that the radius of the rod, held the rod away from the work, caused a 1/32" too narrow piece for the leading edge of the trailing edge. Not having a 13/32 dia. rod, I used a strip of 1/32" balsa under the 3/8 rod. After the first side is shaped, turn it over and use a 1/8" dia. rod to shape the other side.
On wider pieces, using this method, a sanding block is required to do this work, but with a piece this narrow, some careful work with a small plane saved me time and elbow grease. I finished it up with a sanding block and the part came out very satisfactory.
Find the 1.5" trailing edge sheeting in the kit. Use a straight edge to align two of them end to end. Overlap the joining edges an inch or so to set up a skarf joint. Join the two sheets with a skarf joint. Align and join the remaining two sheets in a similar fashion.
On a very flat surface, align and join one of these joined sheets to the shaped trailing edge. Join the other trailing edge sheet to the other side of the shaped trailing edge. The object of doing this is to use the preformed and sheeted trailing edge as a pocket that can be held by the jig.
It works slick, and doesn't require me to notch the trailing edge of each rib. It also means that I can have the top and bottom trailing edge sheeting in place, and use sheer webbing at the front edge of this sheeting to increase the stregnth and warp risistance with out a lot of hassel, de rigging the jig and flippng the wing, or a lot of additional weight.
I used 30 minute epoxy to prepare ribs w-4,w-5,and w-6, for the gear blocks. Only use enough epoxy to make a good joint.You can start to pick up weight if you're not observant.
If you're using a jig as I am, or even if you're not, make a tool to set the spacing between the ribs. This is a simple piece of 1/16" balsa cut to the correct width, between the rib faces.
Remember there's a difference in rib spacing between the inboard and outboard wing panels. Measure off the plans. Carefully align and square up ribs w-1. These are 1" either side of the wing centerline. Care taken here will show in the finished wing, as I am spacing all my ribs from the center line out, using the spacing tools I've made.
Once all the ribs are in place,and tack glued, set the upper and lower spars into place. This is as far as I've gotten to date. More later.
PART ONE B, Finishing the wing.
Carefully assemble and install the Bellcrank assy. Be aware that on some of the earlier kits, an additional washer will be required to secure the bellcrank.
I chose to opt for a more standard installation, and fashioned a Basswood mount attached to the spars. There's nothing wrong with the designed method, I just wanted to use a more familiar method as I was installing the BC while the wing was still in the jig.
I made a new flap pushrod using small dia. carbon fiber rod over an all threaded 4-40 metal rod epoxied into the CF rod. I used a pair of ball links to make the connection to the BC, and later to the flap horn.
I installed .007 CF to the tops of the spars. This really stiffens up the wing. When the leading edge sheeting is installed, the CF is laminated between the spars, and the underside of the sheeting.
It's now time to remove the wing from the jig, and install the leading edge sheeting. I glued the sheeting to the Cf on the spars, using thick Ca. Using a spritzer, I wet the outside of the sheeting and rubed the water into the wood. Now, I used more thick Ca applied to the ribs, and using a flat piece of 2' X 3' Granite, I rolled the sheeting onto the ribs. Using thick Ca is the trick here as it gives you enough time to place the material, but seems to grab rather quick once it comes into contact with the sheeting.
After all the sheeting is in place, I used a modelers plane and shaped the leading edge. I finished up with sandpaper. Using the Flat Granite , the wing remained straight.
Some insist that the only shear webbing to use is vertical between the spars. I've used a Warren Truss like structure with good success in the past. These are made by stripping 1/4", strips out of a sheet of 1/16" balsa. I choose to use this same structure with this wing. With the added CF, Warren Truss structure, and the shear webbing at the leading edge of the trailing edge, the wing is very stiff and warp free. If I really try, I can twist the wing slightly at the extreme ends.
The tips are next. Laminate the pieces, then, after making sure they are square to the last wing rib, glue the outboard tip in place. Tack glue the inboard tip.
I used a plane, and knife to rough shape the tips. Next I finished the shaping with various grades of sand paper on a sanding block. Once the tips were shaped, I removed the inboard tip, and hollowed it out. Using the plans as a reference, I opened up the slot for the adjustable leadouts, and attached some scrap plywood, salvaged from the 1/32" ply that the doubler were removed from. These were glued to the top and bottom of the leadout slot. I assembled the adustable leadout slider, and installed it right to the inboard tip piece.
Next, I fished the leadouts through the wing and through the leadout slider. Now it's time to permanently glue the inboard tip onto the wing. I installed all the cap strips and then gave the entire wing a good sanding, starting with a long sanding block to level up all the cap strips and leading edge sheeting.
I made a mistake and just automatically tapered the flaps. Only afterwards, when starting to fit the plywood clips that support the flap horns, did I notice that the flaps really have to be flat as shown on the plans. It only took an hour to make and finish a new set of flaps, using wood from my scratch building stash.
The flap horn is already set up with corrected geometry, but it was necessary to sand in a small groove at the center of the wing to clear the flap horn. Rather than use brass to secure the flap horn in place, I used a method I've used before. I cut a Sig Ca style flat hinge in half legnth wise. I used an exacto knife to put a slot above and below the brass tubing bearing material. By bending the hinge material into a U, I slipped both ends into their respective slots and Ca'd them into place. I also used some Ca to adhere the hinge material onto the bearing exterior for additional security.
I cut the slots for the hinges, and slid the flaps into place. One item to note, when installing the ball links to the BC, I made the decision to use the middle hole on the BC arm. I wanted to make sure that I could have a minimum of 35 degrees of flap. I figure that if this is too fast, I can adjust the spacing at the handle. The entire wing, came in at 13 oz's, plus or minus, using mostly kit wood. The wing is very stiff, and extremely straight.
Part two, the stab and elevator.
I made the decision earlier to use as much of the kit wood as possible. I almost changed my mind on this as I started the stab. There was some serious die crunching to the tip pieces used for the elevators. As it turned out, I made new pieces but for a differnt reason.
I copied the section of the plans that has the stab and elevator on it, to use as a guide for building. This was taped to the slab of Granite and covered with waxed paper, taped on, to protect the plans. I sprayed the bottom of the center and tip sections, very lightly with 3M so they would stay in place on the waxed paper, since I couldn't pin them into place.
Perhaps I should have placed a piece of Sheetrock over the granite so pins would hold, but the 3M did the job just as good. I measured and cut the leading and trailing edge pieces. a small misting of 3M and they were placed. once all was right, (I did have to adjust the angles of the center and tip pieces with a block sander), a light application of Ca glued the parts securely.
I used a stripper to strip out some 1/2"+ 1/16" balsa from one of the sheets supplied with the kit for this purpose. Using a small balsa miter box, and finishing up with a block sander, I cut and installed the ribs.
I found it easiest to do the straight fore and aft ribs first then fit the diagonal ribs. After my recent experience with building my Pathfinder, I made the decision to build the elevators to the same width as the stab, 1/2" rather than stepping down to 3/8". I know that the theory is that the blanking effect from the thicker stab will soften up the nuetral. It works, but then there's often a slight hesitation when making the transitions during the round eights. By going to the thicker elevator on the PF, the hesitation was gone, and the tapered elevator seemed to track and groove just fine. So, I decided to build the Legacy's elevator at 1/2", the same as the stab.
I located the tip and inboard end pieces. They had, as has been noted before, some die crushing due to the wood being soft and light. I used them as patterns and cut new ones from 1/2" scrap balsa from under my work bench. I can't bring myself to throw away any balsa that might be usable, so that's where I go before I will cut up a new sheet.
I did have to modify them because of what I was going to do in the next step. They would need to be 1/8" wider. I aligned the grains for the pieces, fore and aft where the horns will go, and left to right at the tips.
I did use the supplied front and trailing edge stock though. Since the stock was 3/8" X 1/2", I simply set the front stock up next to the stab, ( still 3m'd to the granite slab). I set it so that the 1/2" side was next to the rear of the stab. I made this piece bridge across the section where the horn will mount to aid in handling and shaping later. Afterwards, I could cut the section out.
I shimmed up the trailing edge, set as would have been normal, with scrap pieces of 1/16" balsa, which I covered with waxed paper to avoid accidentaly glueing the shims to the trailing edge. I stripped some more 1/16" balsa, and using the same method as before, installed the ribs. After all was in place and secured with thin Ca. I removed the stab and elevator from the granit slab.
Ca shore will stick to waxed paper, but the paper came lose easily.
Now, the shaping begins. The stab was first sanded while sitting atop the granite slab. Both the top and bottom were sanded smooth. I then centerlined the leading edge and sanded in a smooth, but rather pointy leading edge. Since Dave Fitzgerald's artical on stab shapes, I've used this type of entry for the stab and found it to work well.
I located the position where the elevator horns needed to be and using a drilling vise, and the drill press, I drilled the holes for the horns before shaping the elevators. I wanted these holes to be true and equal so I wouldn't have to do any tweaking to align the elevators.
Next, the elevator assembly, still joined together, were shaped. I still had the scrap shims under the trailing edge and by using rods for guides, 1/2" at the front, and 5/16" at the trailing edge, I sanded in the taper on the upper surface. Turn over the elevator assembly, and substitute a 1/8" dia rod for the trailing edge. You won't use the shims on this step. Sand the taper. You should have a 1/8" square trailing edge when you are finished.
I wanted a nice taper at the ends of the stab and elevator, so I set the stab and elevator assembly together, on the Granite slab, shimmed up the trailing edge with scrap, and used a sanding block to work a nice taper to the ends,both side, top and bottom.
I cut the elevators loose, I installed the horns in the same way I did the flap horns, after sanding a slight clearance groove in the trailing edge of the stab, located the hinge locations, and cut and temporarily installed the hinges.
The stab and elevators are now set aside.They came out at 2 oz's complete. Next, I made a copy of the vertical stab from the plans to asist assembly the vertical stab. The parts are arranged to resist twisting and warping. A good thing as the main pieces would warp easily until the top cap piece was glued.
I built this atop the Granite slab to assure it was flat. For some reason,Imissed the smallest piece until after I had made a new one thinking it wasn't in the kit parts. Afterwards, I found it sitting right where I had left it.
The forward fillet was too messed up from the die cutting, so back to the scrap bin and a new one was fashioned using the kit piece for a pattern.
I made the shape as the kit was designed, I used a radius sander and simply raiused all the edges except the trailing edge of the vertical stab. Since I plan on using a Rabe rudder, I simply sanded in a 45 degree angle at the leading edge of the rudder, and radiused the trailing edge.
These parts are now set aside until needed. Next, building the fuselage.
Part 3, the fuselage
A decision needs to be made before you begin to build the fuselage. Piped engine or not. Since I was going to use a standard 4-2-4 type of engine, I followed the instructions and trimmed off a slice off the bottom of each fuse side.
The first item in the instructions for the fuse is to cut and install the access door for the elevator horn. Since I wanted this to be adjustable, it is definatley one of those things that is a must do. I copied up the outline for the door and used a slight misting of 3M to stick it to the fuse, right under the inboard stab cutout. Take some time to properly locate the door as it will ease the future construction, and the use of the access panel if it's located correctly.
I used a new no. 11 blade in my exacto, and carefully cut out the door to match the outline. I found the 1/32" plywood tabs, and used some scraps from the die cut sheet to make the stops etc. for the panel.
I opted to use a 2-56 Allen screw, and blind nut, as they won't take up as much room in use. Now is also a good time to install the balsa stab doublers. Later it will be a bit more difficult.
Next, lightly sand the edges of the plywood doublers to get rid of any splinters or whatever, left over from the die cutting, from the edges. I mixed up some 30 minute epoxy, and carded on a thin coating on both surfaces, the fuse and the doubler. Make sure you glue up a right and left hand side or you'll be either cutting new parts, or dealing with trying to strip off one of the doublers.
Using the granite slab as a flat surface, I carefuly centered, and placed the doublers onto the fuse sides. I set weights to hold and apply pressure while the epoxy cured. Once cured, I took a few swipes with the sanding block to clean any problem areas.
I opted to depart from the instructions at this point, and measured and marked a line, on each doubler, where the top of the motor mount beams will be. I also measured and marked a line, on both doublers, where the bottom of the tank floor will be. The motor mounts are shaped for the end, right above the wing, but I wanted to have the option of using a plastic clunk tank, so, following the outline on the plans, I used the bandsaw and removed some material so the RC tank would clear.
I also tapered the mounts, starting just aft of where they will pass through the front bulkhead. The taper goes from full width to about 1/32" at the other end. This prcocedure only takes a few minutes with the bandsaw, and removed almost an ounce of weight from the nose.
Using 30 minute epoxy once again, I applied a thin layer of epoxy to the hardwood mounts where they would contact the doublers. I carefully aligned the mounts with the reference lines I previously drew, weighted them down and let them cure.
While awaiting the mounts to cure, I copied off the top view of the fuselage to use as an alignment guide with my fuselage jig. I set the engine I was planning to use, to make sure the first bulkhead would clear. As it turned out, using the Stalker .61, I had to move the bulkhead to the rear about 1/2".
Once I had this measurement, I drew a line on the topview I was using as an alignment guide, so I could place the bulkhead in the right location. I measured and marked centerlies on all the bulkheads. I was now eady to jig up the fuselage.
Be sure and cover the alignment guide with waxed paper or plastic before you start jigging the fuse. The epoxy was cured, bulheads marked, So after checking that all was square, and touching up with a sandig block. I started placing the bulkheads. F-1 and F-2 were the first to go into place. Make sure the front of the fuselage, the sides, are in the correct location. Once all was aligned, I slightly loosened the jig, removed each bulkhead, one at a time, and applied more 30 minute epoxy to the sides where they would contact the doublers. Use a small triangle to make sure the bulkheads are aligned vertically as well. Recheck the alignment, and when I was satisfied, I tightend the jig back up so the epoxy could cure with some pressure applied from the jig.
Now, it was time to install the other bulkheads. The Legacy uses a combination of straight and angled bulkheads, sort of like a Warren Truss assembly. This really stiffens the aft end of the fuselage, but it's necessary to install the upright, or vertical bulkheads first.
Use the jig to apply a small amount of pressure to hold everything in place as you go. Once all the upright bulkheads were placed, I applied a small amount of thin Ca, and next started installing the angled bulkheads.
Make sure you are trying to place the correct angled bulkhead in the right location. also note, that the pushrod holes will all line up, if you don't try and install one of the bulkheads upside down. The angled bulkheads are tapered, so you will have to work to install any of them upside down.
Once placed, a small amount of thin Ca, and the fuse is basically framed up. I found the balsa tank floor, and the 1/32" plywood for the top of the floor and laminated them together using medium Ca.
Next, while still in the jig, I placed the tank floor into position. Plywood side down, and carefully aligned with the lines previously drawn. Once I was happy with everything, I secured it into place with thin Ca.
After making sure the epoxy was completely cured, I removed the fuse from the Jig. The fuse was perfectly straight and square. No banana fuse when you use a jig.
With the angled bulkheads in the rear half of the fuse, the structure was relativly twist resistant, But, I added cross grained 1/4," light balsa to the top of the fuse behind, and between the first two bulkheads. I made this square, and from doubler to doubler. There's just enough room between the tops of the motor mounts, and the top of the fuse for this. The sructure was now even more twist resistant.
I measured and cut the 1/2" balsa extensions for the front of the fuse and glued them into place. Make sure they are squared up before gluing.
I assembled the pieces that will form the cowl. Note that the piece that forms the top, or bottom, depending on your perspective, is also used to key the cowl into place at the rear.
The instructions for assembling the cowl, seemed a little vague, so I went a little bit on my own here. I first cut and fit the 1/2" balsa at the front, with the grain vertical. Next I stripped out some 1/4," balsa and laminated them to the side pieces, 2 to each side of the cowl opening. I also laid in additional 1/4," strips to the juncture of the cowl sides, and the top piece. (or bottom, once again depending on your perspective.) I also continued with a strip of 1/4, x 1/4, inch balsa in the cooling opening. I glued these right to the doubler, flush with the bottom of the fuse.
I like to see a nice fine line where the cowl and fuselage join, so I cut several strips of 1/64" ply and glued them to the fuse and cowl where they will wind up facing each other when the cowl is installed.
I located the plywood tabs, and after laminating them as directed, I installed them to the cowl, following the plans location. I once again opted for 2-56 allen screws and blind nuts. Make sure when you drill the holes needed, that you have them centered properly. A spot of thin Ca after the blind nuts are seated and they will stay in place.
Now is the time to mount your engine. Be sure and plug up any openings with tissue to keep the sanding dust out of the insides.
I use a variation of Larry Cuninghams' mounting system, but if you're not, you will have to get some .125 aluminum to make the mounting pads from. There are other materials as well that can be used, but, for me, it is simpler to use the aluminum.
After fitting, install the pads with epoxy, and let them cure completely. I use the centering tool from Tower hobbies to make sure that I get my holes drilled into the correct locations. Mount the engine straight ahead, or offset a slight amount to the outside of the circle. Check carefully as you're are working with the fuse upside down and it could be easy to become confused here. Drill your holes, relieve the other side of the mounts for blind nuts, and install your engine.
Take one of the nose rings. I think 1/32" thick is enough and more will only add weight if you laminate the two supplied. Slip it over the engine shaft, use an old broken off prop for a spacer, and mount your spinner. There should be a small gap between the spinner backplate and the nose ring when it's in place. Take the time to do this fitting right,and you'll end up with a nice, even gap all the way around the spinner.
Once satisfied, glue the ring into place on the front of the fuse. Wrap a layer or two of masking tape over the base of the spinner to protect it while sanding and shaping the nose.
Now, turn the fuse over, and tack glue the forward top block in place. Avoid glueing the top of the nose ring to the top block.
I used a small modeling plane to preshape the upper part of the fuse, fairing it into the spinner. Starting with 80 grit sandpaper on a sanding block, begine the final shaping.
Part 3B the rest of the fuselage
Clear the inside of the cowl, so it will fit properly over the engine, and mount it to the fuse. Use a combination of a modelors plane and the sanding block and shape the cowl area, fairing it into the fuse.
Once you are happy with all the shapes, finish up the sanding with finer grades of sand paper. Pay attention to the nose ring as it's slightly too large and needs to be caredully faired into the spinner.
Remove the cowl, and using your carving tools, sand paper and such, clean up the inside of the cowl. I radiused the basla 1/4," strips all the way to the back of the cooling cutout. The exterior is flat and follows the fuse contours, but it is radiused, or coved to the doubler.
Set the aft block into place, and using a soft pencil, outline the fuse sides. Hold the block up against the plans and trace in the top profile, or taper to the tail post. I used the bandsaw to cut the top profile, or taper first. Then with the piece still in place, I cut near the line and removed the excess wood from the sides.
Tack glue the trimmed block to the top of the aft portion of the fuse. Butt the front up tight to the formed front block. Use your plane and sanding blocks to shape the aft portion of the top block. Once you are satisfied, finish up with finer grades of sandpaper.
Note, important, don't glue the rear of the fuselage together until after you have installed the stab.
Break the tack glue spots loose on the two top blocks. Transfer the bulkead locations to them, and hollow out the blocks. Leave some material so the block contacts the bulkheads. I try for as close to 1/8"thickness as I can get.
Once hollowed to your satisfaction, You can glue the front block into position, but hold off on the rear block so you can install the wing, stab, and pushrod assembly.
The fuselage is now ready for the next step, installing the wing and stab. It's going to look like an airplane soon.
Part4, Putting it all together
Now, with the parts completed, it's time to put it all together and make an airplane out of it all. Alignment is one of the most important items to get right on a competitive stunter. This is the point where some extra time spent will be time worth more than the effort.
I've used jigs to insure that the parts are straight, it would be a shame to now just slap them together when it looks about right. So with this in mind, here's how I did the assembly. First, follow the instructions and remove a portion of the fuse sides above the wing cutout so the wing can be slipped in its' place.
Second, mount the engine solidly in the fuselage. Block the fuselage up in some fixture so it won't move about. In my case, I used some scrap pieces of balsa to lift the fuse high enough so that the engine head would be clear.
I've seen some really neat ways to build a holding jig for alignment purposes, and recommend constructing one to use with your models, but I haven't yet.
Slip the wing into place. test fit sand sand away any clearance problems that may be there. Align the center line of the wing, with the centerline of the fuselage. There are several good methods to make sure the wing is straight and aligned. I used a trammelling method that has worked well for me for years.
This involves a strong straight pin and a legnth of heavy thread.
Insert the pin into the tail piece on the fuse centerline. Measure out and mark the wing trailing edge two points equidistant from the center of the wing.
Because of the different rib spacing on the inboard and outboard panels, you won't be able to use the tip ribs as a reference.
Now, pull the heavy thread to the point where it intersects with the mark on one of the trailing edges. Mark the thread with a marker, and now, using the same amount of tension, see how the mark on the thread relates to the other trailing edge mark.
Move the wing slightly until the marks all line up. The wing should now be squared up to the fuse, but it is still necessary to adjust the tilt, side to side of the wing.
With the fuse blocked up and secured from movement, measure the distance from one tip to the base that's supporting the fuselage. Measure the other tips distance, and adjust until the measurements are the same. The wing should now be level.
Pin and tack glue to hold in place. be real stingy with the glue if you tack glue as you still need to adjust the incidence.
I like to set everything up at 0-0-0 incidence. here's the method I use to do this.
I use two incidence meters, but, it can be done with only one. It's just simpler to use two. Here also is the importance of securly blocking up the fuse as well. Set one of the incidence meters onto the shaft of the mounted engine. If the meter reads other than zero, that's OK, but it should be close.
Mount the other incidence meter to the wing, close to the root.
Compare the two meters. They should read the same. If not, adjust the wing until the two meters agree. It's also a good idea to check the tramelling and wingtips after each adjustment. Once the meters match, you have the thrust line and wing centerline zeroe'd out.
You can now tack glue to your hearts content. I use pieces of scrap balsa as shims, and thin Ca to tack glue the wing into position. When I do the final glueing, I'll use 30 minute epoxy.
Now, set the stab into position and pin it into place, matching the stab centerline to the fuse centerline.
Move the tramelling pin from the rear to the front of the fuse. make sure it is placed on the centerline near the nose ring. Since most stabs are not offset as the wings are, stretch the heavy thread to the tip of the stab at the stab trailing edge on one side. transfer to the other side. By moving the stab slightly, and re- tramelling, you'll soon have it aligned. It's good practise to also check the distance from the wing hingeline to the stab hingeline. The measurements should be the same.
Now, as you did with the wing, measure the distance to the base and adjust the tilt until the measurements match. The stab should now be aligned. check all measurements once again, pin securely and move the incidence meter from the wing to the stab root. Adjust the stab until the incidence meter readings match for a 0-0-0 setup, my prefered setup. If you want some positive incidence in the stab, it will be a simple matter to put it in, using the incidence meters. Once set where you want it, tack glue securely.
Re- install the section of the fuse removed earlier. I used small pieces of 1/16" balsa to einforce the cuts. It was also necessary to instal some thin slices of balsa to make up for the material removed when sawing the fuse above the wing cutout. The plane is now aligned and ready for the epoxy final glueing.
Mix up enough 30 minute epoxy to glue the wing and stab securely. The tack glueing with Ca will hold the alignment while the assembly is moved and the epoxy is cureing.
It's time to install the elevator pushrod. I chose the Dave Brown Cf tube pushrod. There are other equal or perhaps even better choices. I used a ball link at the flap horn, and chose a clevis for the elevator end.
It's pretty tight at the tail end of the fuse, and not much else would fit. I used the Great Planes version quick link as I've experienced no failures with their link used with the fuel tubing safety tubing.
Part 4B; Closing in the fuselage.
Install the previously shaped and hollowed rear top block. Glue the tail piece at the rear of the fuse securely. Turn the assembly over. Construct and install the tail wheel mount.
Since I am using the big Stalker, I had to come up with a way to mount the muffler that would allow me to easily remove the engine. What I came up with seems to work well and doesn't add much weight either. I went to Lowes and purchased a 1 1/2" 3/16" dia. nylon machine bolt and nut. I laminated two pieces of scrap plywood to two pieces of scrap 1/2" balsa, 1/2" X 1/2" X 1 3/16" long. I made a filler piece to fit the bulkhead where it was cutout for the pipe out of 1/8" medium hard balsa. before glueing it into place, I drilled a 3/16" dia.hole on centerline, and at the proper height to support the muffler. I slipped the nylon bolt through the hole, and set the laminated ply and balsa close to the flats of the nylon bolt so it would be ablle to move fore and aft without being able to turn. I placed the nylon nut on the other side of the filler piece. By turnig the nut, the bolt will slide out or in, depending on whch way you rotate the nut.
Once the muffler is in place, simply rotate the nut, which brings out the bolt until it contacts the inside of the muffler securing tube at the rear of the muffler. Now that the muffler is secured, it's time to close up the bottom of the fuse.
Install 1/8" balsa, crossgrained as per the instructions. With the 1/8" X 1/8" balsa strips, as per instructions. There's enough material to make a nicely rounded corner on the bottom of the fuse.
Sand and finsh the entire fuse, starting with 120 and finishing up with 320 grit sand paper on a sanding block. Install the vertical stab, making sure that it is not offset in either direction.
Temporarily install the flaps and elevators. I previously marked a centerline for the wing and stab, so it was easy to set the flap and elevator fairings in place.
More sanding to make it look nice. Use some thought on the rudder. the most often suggestion is to use minimum rudder offset to reduce yawing effects. There are several methods to make the rudder ground adjustable and I would recommend that it have some adjustability.
In my case, I made mine a Rabe rudder. There are several methods available to set this up. The one I used involves a short legnth of right angle brass stock with hole drilled every 1/8" along one side. This is mounted to the bottom of the outboard elevator. I used an RC strip aileron mounted on the bottom of the rudder with a 1 1/4" long 4-40 bolt as the rudder horn. Mine has a slight offset at nuetral, There's a maximum of about 10 degrees offset with full down, and substantially no increased offset until the last few degrees of up elevator.
I chose to add the canopy after the fuse was covered with silkspan.
Part 5, finishing with iron on covering.
I like to weigh the plane before any finish is applied. It gives me an idea of where I'm at and how careful I need to be with the finish. To do this, I install all the components. This also allows me to check fits and such. Mine weighed in at 50 oz's with all components and no finish. My target weight is 60 oz's so I have 10 oz's to use with ny finish.
All during the building process, I was thinking about the color and trim scheme for the plane. I made some decisions early on that I wanted some type of Racer theme. It would use some checker board patterns. I decided that light colors would be prefered as some of the places I was planning on flying competition had trees close by where my experience with darker colors was that the plane dissapeared into the background. It made for more difficulty with the bottoms.
I decided on two colors, white and yellow as the major colors.
Now, to make something that looked good and included the choices I had made.
Fortunate for me, I have the computer files and was able to copy off the side and top views to use for trim layout. Another advantage was that by using the computer and different colored layers with the hatch command, I was able to layout the trim in colors to see what was most visually appealing to me. Another advantage is that I could plot out full scale patterns to layout the trim accurately. It really made this part fun and interesting.
I had already made the choice to follow my usual method of monokoted flying surfaces and painted fuselage, but I wanted a semi- transparent look to the wings, similar to dyed doped silkspan. In the past I've used Coverites' Mica film. There isn't too much of this covering available any longer, and I wanted to try a method used by fellow club mate Norm Whittle.
He applies monokote over doped silkspan, and his planes look very good. So the choice was made to apply silkspan over the entire plane.
Prep the plane by sanding well and removing any ridges that might show through the `Kote. A problem with `Kote finishes are those bumps and ridges that show up like a boulder under the covering. Careful sanding before applying 3 coats of nitrate to the surface of the plane all but eliminated the problem. A final sanding with 320 wet or dry before applying the kote finish to the flying surfaces took care of the rest of the virtually eliminates the problem.
Another advantage to applying a kote finish over a substrate is that even elaborate trim schemes can be easily applied without having to apply `Kote over `Kote, or making up panels out of pieces of `Kote.
I use a pinked edge next to the fuselage so that the epoxylight fillets will cover the edges and still have good glueing to the under structure. This edge is first tacked into position, and the rest of the panel is pulled tight and tacked at the other end.
There is a learning curve I discovered as I ironed on my first panel. Simply put, Start out in the center, between the ribs, and using a socked iron, stick the `Kote to the doped silkspan. be careful as too much heat can cause the dope to bubble and the bubble will show whitish under the transparent MonoKote.
Work fast, from the center out, in the open panels, until all the panels are securely fixed to the open bays. Do the bottom first so your mistakes won't show.
Once the open bays are affixed, stretch and tack to the leading and trailing edges. Now, use your heat gun to shrink the `Kote tight to the leading and trailing edge sheeting.
Now switch back to your socked iron and stick the `Kote in these areas. Done carefully, it will look like dyed doped silkspan rather than transparent MonoKote. A much more pleasing effect, in my opinion.
I left out covering areas that would be a differnt color, to be applied later. It seems that MonoKote applied this way sticks quit well and doesn't have all those bubbles gasing up and looking unsightly. Some of you know how to heat form the `Kote at the tips.
This was a bit more of a problem over the silkspan. Coupled with the radiused tip blocks, I wound up with a bit more wrinkling at the tip lap joint than I would have liked. I believe that with more practise with this method I'll be able to avoid this problem.
Once all the transparent yellow was in place, it was time to apply the checkerboards. Hanger 9, who distributes the old Goldberg OraCover, has a checkerboard covering in at least 2 colors, Black and White, and Red and White. I used the Red and White. It also went well with this method, though less heat was required. Sure made nice looking checker board panels. far better than applying the checkered portions later over a white background.
Strips of white, red,black and metalic plum comprised the rest of the trim on the flight surfaces. These, due to their width, was applied right over the other coverings. The flaps, stab, and elevator were also covered using this method.
The flying surfaces are now completed and it's time to paint the fuse.
Part 6 Finishing the fuse.
I started the fuselage prep, by first installing the canopy. The canopy for the Legacy is set lower than normal, though most completed Legacys' I've observed have the canopy set too high. The idea is to give it that low lean racer look, and a too tall canopy sort of spoils the effect. At least in my opinion. I spent a bit of time cutting and fitting the canopy. Once I was happy with the fit, I laid a sheet of 320 open coat sand paper over the section of the fuse where the canopy will mount. I set the canopy on the sand paper and by moving the canopy fore and aft, I was able to get a good final fit. There will be some white colored sanding dust on and in the canopy that will remove easily with a soft cloth.
If you've decided to paint the inside of the canopy, now's the time to do this. Some paint a solid color,others like a tinted look. I chose a solid silver.
The paint I used was from the hobby shop. The small rattle cans from the RC car section. This paint is made to adhere to plastic car bodies, and is fuel proof as well, for those applications where fuel may come into contact with the paint.
To get a tinted look, First spray on a misting of a transparent color, such as blue. Once it is totally dry, spray on silver. It'll look like candy blue and depending on the shading effects will look rather realistic.
Locate the canopy by measuring back from the nose ring 10.375 inches on the top block. This is where the front of the canopy will be located. Center out the canopy on the fore - aft centerline and while holding securely, draw a line, with a sharp #2 pencil around the outside perimeter of the canopy.
Remove the canopy and use a new blade on your Exacto knife to cut a thin groove for the bottom edges of the canopy to set down into. Apply a bead of RC-56 glue to the bottom edge of the canopy. Be careful, but since RC-56 dries clear, a small amount of slop can be tolerated.
Use masking tape to hold the canopy in place while the glue dries. If you haven't already, it's time to epoxy the wing and stab into place. 15 or30 minute epoxy will do the job quite well.
It's time to install the fillets. Some like to use leather fillets,and they tend to come out very nice, but can add more weight than the method I use. First, protect the flying surfaces by using tape where the fillets will end out on the flying surfaces. You can also mask off the wing and stab at this time. I would suggest you do so.
I mix up some 15 or 30 minute epoxy in a mixing cup. Then I thin it with alcohol about 25%. it becomes about the consistency of dope. A mixture like this can be used to fuel proof the engne compartment and I also recommend this move.
For the fillets, after thinning the epoxy, add micro balloons until the mix is a rather thick paste. I use my finger and lay in the filets with this paste. You can do a final tooling with the tip of a spoon or some other round object. Let it dry completly, usually overnight. This mixture once cured will sand easily, and the fillets can finish up really nice. A thin coating of spot body putty will finish up the fillets to a very smooth look.
Remove the tape on the flying surface and retape it out about 1/8". Now, you can sand the edge away on the flying surfaces. Sand until you have a smooth transition to the wing and stab. Now, remove the tape and reapply once again about 1/8" further out. This will be the paint line, so make it straight, especially if the fuse color is different from the wing at the root. While you are doing this to the fillets, you can do something very similar to the canopy. You'll wind up with a nice filleted transition from the fuselage to the canopy.
Check over the entire fuselage and fix any dings or problems with the spot putty. after sanding and using a tack rag apply 2 to 3 coats of butyrate dope over the nitrate previously applied. Sand with 320 wet or dry, whipe and tack thourouly. Apply one or two coats of primer, such as Brodaks white primer. When dry, wet sand until most of the primer is gone and the fuse feels very smooth.
Whipe and tack once again. Your choices for paint are many at this point. For me, I chose to use Luster Kote because of it's match to MonoKote colors. I've used it before and found it to work well, dry rather quick, and be reasonably fuel proof.
My base on the fuselage is white. It's a good choice as a base as other colors applied over it will appear bright and clean. 1 mist and 1 full coat was all it took. It was ready to mask the trim in a few hours. The rest of it was mask and spray, mask and spray, until I had all the colors on. 4 colors in all. At this point, I haven't sanded the tape lines as I want to make sure they are absolutly cured.
Luster kote has a gloss clear coat I can use for a final coat. I'm also testing to see if clear dope can be applied over it as well. The plane is finished and with everything weighs in at 59 oz's. The total finish then, is 9 oz's. It might have been less if I hadn't used `Kote over doped silkspan, but then it wouldn't have the look of dyed silkspan either. I plan on test flights as the weather improves, and pictures as they come back from the developers.
I'm wondering why everything is spinning around?
John Miller
