That's not what I'm saying. I don't fly mine with top wing positive to lower wing. At all.

Don't recall saying you did....

Didn't mean to upset you.... Just trying to figure all this out...

Fight nice, guys. ;-)

I futzed around with MS Paint and came up with an acceptable rudder bash. I'll core it with 3/16 sheet balsa top and 3/16 ply below (to absorb the pull-pull tackle) and then sheet both sides with 1/16" balsa. May not bother with the lightening holes as I figure she'll likely need tail weight when I'm done, anywho.

Iron cross, you have it backward, upper wing negative with respect to lower wing. This has held true on at least the last 7 bipes I have built. Charlie P, no, all my bipes (for best flying and no elevator trim change being required with throttle change) like lots of down thrust. If you do not, you will have to fight the elevator trim every time you change throttle settings.

Is that negative with respect to the bottom wing or the horz stab ???... I am looking for a nice stable flying plane, not a 3D one.. Will the negative give me that ?.. Man, can't believe BUSA would give me bad info like that... Know what I mean... With the bottom wing in the saddle as per build it came out plus 2 degrees to the horz stab.. The top wing was at zero as built... It sounds like this was designed right but BUSA doesn't know it... No incidence mentioned on the plans or manual for the II, that is why I contacted BUSA.. I spent a couple hours sanding out the wing saddle and shimming the top wing to get that :-(
Even worse I went to there web site just now on the Phaton 90 info page it calls for the plus2 on top and negative on the bottom ARRRRGH

A conundrum to be sure. We want a biplane that has negative upper wing incedence for stunts, but a positive incedence for take-off and landing . . . with a tail that has positive incedence for level flight at mid-throttle and above but "squats" at low speed for landings.

Flaps actually chance a wing's angle of attack. The rear 10% of the wing bends down so the wing's datum line tips down at the trailing edge with it. Be awfully complicated to build the Phaeton with dual & seperated upper servos that act as flaperons while the lower ailerons remain only ailerons (especially as the stock build is a single central servo and lower ailerons only).

What you have to do is build for the maximun performance at the operational points that are most important to you. The pattern ships and better aerobatic models have adjustable incedences. Wouldn't that be nice.

A conundrum indeed .... I went to GP and looked at there tech notes... The incidences seem to be all over the placve but generally the top wing is negative to the bottom on there biplanes... Guess I will be bringing a lot of shims with me..

Templates for the empennage sheeting. I've got a set of plans on the table, a rolled set for reference and because I like a clean set for future use(?) and so I traced out the template on paper. Not sure if I am just cheap or plain stupid. Anyway, it works.

Pinned and weighted. The fin calls for a 3/16" x 3/4" block for the upper tip. Darned if I could find any likely source in the kit box. I laid three 3/16" x 1/4" strips together. Adapt, adopt, improvise, overcome.

Back to the tail incedence. One Phaeton I remember seeing at a Fun Fly was a "dog". It appeared horribly underpowered even though it had a 120 size four-stroke on it. Watching that plane was one of the reasons I decided a little gas engine would be the way to go. I wonder now if the owner had put some negative tail incedence in by mistake. It moved well enough that it should have looked OK, but the tail was low in flight so it appeared to be struggling. I'm throwing in a hair of positive incedence in the tail relative to the lower wing, maybe 1Âş, and I hope I don't start "chasing my tail" (n'yuk, n'yuk) with conflicting incedences.

At this point:

Upper -1-1/2Âş
Lower 0Âş
Tail +1Âş
Engine horizontal 2Âş right
Engine vertical -2Âş

Completely sheeted vert stab. Of course at this point I found the 3/16" x 3/4" x 4" strip for the upper stab (in the hardware bag).

Came up with a rudder by dropping the angles off a couple side photos and the one line drawing I have. It's a sandwich of 3/16" balsa core with a 3/16" plywood stiffener in the base. On either side of that are 1/16" plywood insets flush with the 1/16" outer sheath. Should provide a good anchor for the tailwheel torque rod and as a base for the pull-pull control horns (which will actually be a single through-bolt).

Side panels for the turtle deck. These need to be tapered down towards the rear. Found that former 7 is about 3/8" too tall. Die-cut and plans pattern are wrong but the side-view is correct. Harumph. Easy fix, but scared the crap out of me when I dry-fit the top sheeting.

I also figured out what the written line: "Note that the bottom edge will have about a 1/8" curve to it" means. I radiused the inner edge with a razor plane, but what I should also have done was to trim the side sheet because it bowed up as I bent it inward. Did not notice this when I trial fit and "T" pinned it in place. Oh well, that's what balsa filler is for. There's a little "smile" along one side where it meets the longeron. I'll splice and glue in 1/32 balsa strips and then smooth with wood filler.

Core and sheeting piece for the rudder.

Gray lines are the original silhouette and the red is altered state. Makes you wonder if the same hand that drew up the sweet curves of the P-40 was at work here. Angular and lovely it ain't, but distinctive.

Core glued to starboard sheeting. You can see the ply pieces. Some "augmentation" of the elevators so I can reshape the edges to a shape more similar to that of the Curtiss. Actually the tail doesn't look so bad when viewed in total. The Curtiss has a straight vertical hinge line but the rear swept line of the Phaeton makes it appear "finer" at the top even with the vertical trailing edge.

Good thing the weekend is here - I'm caught up on my images.

Let me see if these come out legible. These are a pair of magazine articles (e-mailed to me without giving me a source for either, unfortunately). Both articles had some good suggestions.

Thanks Charlie. Thats a keeper. The artile I have is a magazine article and didnt cover the top ribs issues.
Edwin

Some interesting information there... Man that article goes back though ... 71.49 for the kit ?... Ahh, the good old days...

I'm at home on dial-up (we don't even have cable available out here in East Bugnut) so these will be in short bursts.

I used a straight spar to describe the line down the top of the frames for the turtledeck.

By laying pins on the top of the frames and pushing them through the side sheets, then laying tha spar on that I was able to find the straight line (this is a boatbuilding trick of sorts).

I scribed the line with a ball-point pen (easier to draw with and see on balsa) and then llifted the spar 1/16" to allow for sanding to the proper angle. You can see the "trapped" pin that shows I'm pretty close to done at the initial cut. A spirit level and a razor plane, then 150 grit on a sanding block and it is flush to the frames in 15 minutes.

Got a bit of a pucker on the port side but I can fix that when gluing on the 1/4" deck sheeting. I have to finish up the empennage before I can attach that.

Hoe Lee Crap. I had to hacksaw 1/4" off both sides of the mounting plate to squeese the Zenoah G-26 in. It looks like 1-1/8" recessed for the firewall. You may have too much engine if your throttle lever is OUTSIDE of the widest part of your fuselage. May not be a scale fighter, but it makes up for it in spirit. An engine with wings attached. Who was saying they stuck a G-62 in one of these! Shazam!

For better or worse here are the tail feathers. I struck the angles by eye and radiused the edges with a pencil compass without defiling the inner 1/4" framing. I have no really good overhead or under views of the F6C. The two shots I have show that the fixed portions are MUCH smaller than I am putting on. I just didn't want to stray too far from the Phaeton and end up with an unpleasant flying model. Or worse yet, have something fold up in flight because I was overstressing the design. The rudder is about 25% larger than the plans and the elevator halves about 10%. The elevator area is moved closer to the centerline, which puts it more in the disturbed air of the fuselage wake, so the net change (I hope) is about nullified. The plans only call for 3/4" up and down travel, and I'll probably get more than that on high rates by the time I'm done.

Just have to shape the edges and the tail is done.

Geez, forget the fuse and just glue the wings to the engine!

Lookin' good!

Chris

Thanks.

Yeah, I guess I can toss the two-piece cowl that came with the kit.

No matter how you slice it, the carb is outside any cheekless cowl. I have a bunch of balsa blocks and I'll get most of it hidden . . . maybe. The Curtiss has an especially "klunky" nose. Maybe I can add yje figure of a panicked ground maintenance crewman hanging on for dear life to camoflage it?

Any bets on how much lead I 'll have to add to the tail when all is said and done? Servos will be in the main fuselage (I don't put servos where they show) and I'll have two battery packs over the lower wing T.E..

Hinging the elevators. The right side is done and the left side is next.

Hinge line at full deflection. I used DuBro heavy duty pinned hinges that can be removed.

My high tech hinging tools. A hacksaw blade forked and sharpened on one end and sharpened around the curve on the other. I also use a centering tool to scribe the center-line between my pencil marks. The little "digger" is a handy thing for worling out the crumbs, and flipping the hacksaw bladed side-to-side allows me to square up the slot sides.

Another dry fit to see how it sets. Bottom will be sheeted and the tail wheel block & mount will eliminate the "step" at the base of the rudder. The top needs a bit more sanding work to smooth the top line from stab to rudder.

March of the lead and jigs. The trailing edge is pinned, lower spar is propped up on scrap 1/4" pieces with "T" pins beside it to align it and then the little plastic jigs are used to align the ribs. The 1lb lead ingots hold the upped spar down, 1/2 lb ingots to hold the rear of the ribs to the trailing edge, and I just work my way down the panel with CA. I like to build with Titebond II, but I will endure the CA fumes and assorted risks for hos easy it makes framing up wings.

I did trim two ribs to accomidate the sheeting I will add in the bay that will sport the aileron servo. Haven't decided on just how that will be mounted, but that can all be added later.

Lower wing panels in progress. Only one of four leading edge sheets in place. I have to add holes for the servo wires, and this is as good a time as any. Could also have been done when the ribs were first collected together.

A load of 85 grains of FFFg blackpowder and a .530" patched ball should just do it. (Seeing if anyone is still paying attention, here).

Sharpened the inside of one end of a copper pipe and crenulated (now there's a wood that doesn't get much use) the edge with an emery wheel, both steps with a Dremel. By placing a scrap block of pine behind the rib and pushing the sharp edge in while twisting it is simple to pass a nice, straight channel through the ribs.

I formed paper tubes by rolling 8-1/2" x 14" copier paper on a diagonal and threading it through the holes, then back-twisting to get it to open up to the full diameter. The tubes are then painted with water-thinned Titebond II and the ends cut square with scissors. By no means structural, but the Titebond II bonds the paper to the full circumference of each rib with 100% contact. The Phaeton has pretty lightly designed wings, and I hope this hasn't weakened them excessively. I'll do an "oomph" test and if I start to hear "pops" when I lift the end of a panel I'll sister below the tubes with 1/8" square stock.

Fairing the decking at the tail. A bit more sanding needed but it's shaping up nicely. I filled one "dip" in the side sheeting with Elmer's Carpenter putty and will sand it fair. Otherwise, it came out nicely square and true.

hows the progress?
you are doing a really nice job on those wings.

Thanks. I have the lower wing(s) sheeted and ready to join. I figured wing panel shots all look about the same so the “filming” has slowed. I was hurrying for a mall show our club is putting on and glued up the wrong spar so I had to unglue it and start over.

Put together a little binder of “documentation” on the Curtiss to set on the table with the fuselage. Boy, just adding the wheels (1/5 scale “vintage” DuBro wheels at 5.6”) sure makes it look like a proper little airplane! I mocked up a foredeck out of light cardboard just to shape her out a bit which also helps. I’ll post an image of her at her first “show”.

Here is the prototype Curtiss “Hawk” in the 1925 brochure and the D-12 engine, both with specs. Kind of faint, but it is amazing what can be dug up on the Internet.

Before I join the wing halves I want to install the servos and flush hatches for the ailerons and finalize what I am going to do about the wing tips. The larger forward portion Phaeton wingtips are much different than the round Curtiss ones. If I build out the center I’ll have to change the whole support design – which is a forward solid balsa block - possibly adding more weight than it will be worth. All I need do for the servos is cut out the inter-rib sheeting and add hardwood strips to screw the 1/8” plywood hatch to. Slotting the hatch for the servo arm is the only fiddly bit with that.

I’ve also been thinking on the aileron control horns and I believe I am going to fashion my own. I was going to use Sullivan horns, but I have a method of “horning” an aileron that I came up with that leaves no visible hardware on the upper and very little on the lower that I may just try here. I was going to fashion the upper-to-lower aileron linkage anchors myself, and a control horn that matches will look better.

Beginning the top wing. Thinning the airfoil – I traced a pattern to alter the rear profile of the ribs to accomidate an aileron and to lower the spar and “hump” of the airfoil by 3/16”. To keep the basic profile I used the female scrap of a die cut rib to strike the upper line. The plywood pieces in the image are also the saw-stop for a razor saw. After those two vertical cuts I squared up the bottom using an X-acto chisel; shuffling the ribs until they were even. Then I tightly rubber banded two sections of spar (the excess from the lower wings) set into the slots and did the shaping with a razor plane and 80 grit sanding block. Again, shuffling the ribs and checking for square across the stack from each side with a carpenter’s square. I trimmed the trailing edge to bring the thickness forward enough that a 3/8” x 1-1/2” aileron stock would blend in for the “new” upper ailerons. Note that the inner six ribs will be under 3/32" sheeting and the inner four are shorter to accomidate the pilot's view cut-out; but they have a common leading edge so I did them all at once.

I sandwiched a 3/16” square stock strip into the provided trailing edge lower flat and upper tapered stock. The tapered trailing edge piece will go over the 3/16 shown in the image. The “tail” in the ribs was left a little long and “fat” and I trimmed to length on the pinned down flat piece and then used a single-edge razor to flush the top even with the 3/16” strip for the tapered stock. I also added two pieces of scrap 3/16 pieces into the T.E. of each of the bays where a hinge will be for added “beef” in anchoring the hinges. Note that the plywood strips in the image will go on the BOTTOM of the wing for “N” strut anchors once I get the ribs trimmed.

Mocked-up the foredeck and fit the wheels. The cowl will need be another 2” longer than the piece shown. The firewall will be inset to about where the forward rubberband is placed. I’m going to hold off epoxying that in place until I can test balance her “pre-covering”, hoping to minimize any added dead weight for balancing. Lighter flies better.

I have 1Âş positive incidence set into the tailplane using the forward deck (top of the plywood doublers) as the datum line. Figured that was a good place to benchmark as I can use it for both wings and the engine offsets.

Naturally, you're right about lighter flys better. However, mine came out to 14lbs. It was swapmeet plane 80% built. I bought it cause it was built straight. What I didnt know then was that the aft fuseloge didnt need to be sheeted. Was already done that way. With a saito 120 it flys pretty slow but with ailerons on both wings on high rates it is incredably menuverable. Just love it. I bought the plans to get the CG and will build another someday. So many have put gassers on them that I just have to try that some time.
Edwin

So far I'm very pleased with the kit. It has been fun to build. Some kits seem to require four hands and special jigs or tools. This is as simple and straightforward as can be. 1960's building technology - right up my alley.

My goal is to keep it under 13 lbs, but that will be tough with 59 oz of engine and the added components of the smoke system and 8 oz of receiver batteries, 4 oz for the two added servos (smoke & dual aileron), etc. It adds up quick. I have resisted the urge to "beef up" any areas beyond the design. I have a bad habit of reenforcing frames and adding webs when I am building. One spot I did add two triangle-stock sections to was each side of the last "cabin" framework where it transitions to open framing in the spot rght below the rear of the cockpit. It just looked like a "hinge" point for really hard "plops". The added webbing on the outside as called for on the plans is, no doubt, adequate.

I'm also surprised the upper wing had the spars butt-joined with no solid cross-pieces of any kind. All other straight wings I have built up in the past have either full length spars or a flat plywood cross-over piece (the lower wing has a plywood brace with the dihedral incorporated). This design has continuous (one piece) 3/32" balsa sheeting top and bottom for the first three ribs on either side and nothing else but the cement on the innermost ribs laid together. I did not cut the 3/8" x 1" x 10" +/- rear crosspiece at the wing cut-out, so that will add some strength. I'll most likely slide a piece of ply behind each spar up to the second rib on each side. Probably plenty of strength with the cabanes spreading the load out away from the center section, but I just can't help myself. Maybe just a thin slice and fiberglass strips laid over the spars.