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Mar 06, 2012, 07:08 PM
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Build Log

Dare Design Sopwith Camel


OK, yes I am at it again. Those of you who survived my lengthy Halberstadt post will be relieved to know that the Camel will not be as excruciating - scale but fun and not crazy. I have another crazy one coming soon.

I bought the kit at the WRAM show and I should really learn my lesson not to buy kits. I always do and I am always left wanting. Perhaps it comes from being a perfectionist and doing my own designs, from being a modeler for almost 50 yrs or from the concept that IMHO kits should exist to take the guesswork out of a subject when you don't feel like thinking too much and redesigning everything.

The dated, hand drawn plans and supplements leave a lot to the imagination and the building instructions are little more than "build, install, fly...". Again, IMHO plans should stand on their own and a decent or not so decent builder should be able to glean everything he needs from the plans. Period. No guessing, no reading, no emailing, no cursing. Those of you who have seen my Mosquito or Storch plans know what I mean. There is no mention of using an elec motor for propulsion so what we really have here is a conversion of sorts. You are also on your own for a battery/ESC/receiver installation, servo installs and control methods and routing.

While the kit is laser cut, all that you really get are the wing ribs, ply interplane struts, ply firewall, some ply infrastructure pcs, the empennage cores, wing tips and the turtle deck formers. The rest is tradtional sticks and bones. I am not complaining about the latter as I like sticks and bones construction, but there are ways to make it easier and stronger w/o adding alot of weight - like gusseting. See the photos - easy to do if you have a laser. BTW the vac cowl is very nice, but the firewall had a larger dia which would have resulted in a maddening problem at the end with few decent options as to fixing it.

I felt that the 1/16 balsa ribs were way too flimsy and my mantra is ply ribs for WWI wings, I don't care how much they weigh as wings don't weigh that much in the first place. I need it to hold up through the building process and for a few bad landings.

What you have here is an old school free flight design from the 70's (?) that was fluffed up a little with laser technology. The drawn outlines on the plans look very accurate however and 1/8 is a nice size for this subject.

OK, I have had my day in court. Let's get on with it.....
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Mar 16, 2012, 08:55 AM
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Joining the fuselage sides


After framing out one side on the board, I framed the other over the first - separating the sides with wax paper. This is a tried and true old school technique as it really doesn't matter too much if the sides differ slightly from the plans - it only matter that they are the same. Critical here while framing is to get the bass nose stringers perfectly aligned with my "half inch extra nose" marks I made on the plans. This way, when the sides are stood up, I know that all four nose stringers will terminate square at the firewall.

I stood the two sides up over the plans and, with the nose aligned with my marks and the sides perfectly in line lengthwise with plan's sides, I pinned in my jigs as per the photos. Note that the fuse is joined inverted as I wanted the "truer" plane to be at the cabane mounts. Also note that you cannot pin through 1/8 sq bass wood as it will split. While I was framing the tail cross members which I did first, I used a massive block of aluminum to keep the front end from wiggling around or twisting.

Even with all this, I still have a slight "rack" in fuselage when viewed from the front of about 1/32 - 1/16". Not much you say, but a big deal out at the wing tips since the cabanes will now be off. I will level this at either cabane mounts or in the wing's center section.

Last, note the heavy use of gusseting. These things weigh nothing, give you a ton more gluing area and impart serious strength to the framework in resisting twist and broken glue joints that you will never see once covered.
Mar 16, 2012, 09:51 AM
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I have always had an aversion to jigs etc but have built my share of "banana" planes. The details left out of kits like this are kind of welcome to exercise my 73 year old brain, just a little. Good luck with the build and hope it flies nice.
Mar 16, 2012, 10:08 AM
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Jigs


Quote:
Originally Posted by E-Challenged
I have always had an aversion to jigs etc but have built my share of "banana" planes. The details left out of kits like this are kind of welcome to exercise my 73 year old brain, just a little. Good luck with the build and hope it flies nice.
E - I was cutoff in one of my captions and started to say that external "L" jigs or similar would work also. When I design my models, I employ self-aligning, interlocking parts at least one plane of which rests on the board. No such luck here and, after looking at the result a little more, I am rusty as I have not built a "real" sticks and bones model in quite awhile.....It's "straight enough, but not perfect.
Rob
Mar 16, 2012, 12:42 PM
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More framing


I installed provisions for the aileron servo, the plan being to use an EZ connector to pick up flex cables coming in from the lower wing panels. I used this set up on my Mosquito and it is positive and slop free. Like motorcycle cables, RC flex cable sheathing need only to be secured to framework at ea extreme end - the rest of it can be allowed to flop around w/o any effect on control surface play, but keep the free runs to the servo or control horns short. If they get long, run some solder in the free ends to stiffen them up.

I 86'd the plan notation to completely sheet the underside of the fwd fuselage and instead made a long 1/8 lt ply plate with access openings for the aileron servo and - eventually - the batts and the rudder/elev servos. This plate incorporates a 1/2 bulkhead for the LG and the fwd end of the aileron servo mount. The orig design was fine for a FF model, but not for an RC electric with "stuff" inside.

Ultimate plan here is to mount (2) 1000 mAh lipos to the rear of the firewall - my prelim test fitting against the plans say that they will just fit.
Mar 16, 2012, 09:05 PM
Registered User
Nice neat work.. better than most. Although you needn't putty the fuse sides as Flat sanding the fuse sides..before joining.. is a superior technique.
Mar 16, 2012, 11:34 PM
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Filler boy


Yes I should have done that but in this case the bulkhead that was installed after the sides were stood up was a bit shy of the sides. Also the side sheeting there could not be installed until after the offending bulkhead was in situ.
Mar 17, 2012, 01:45 PM
Lori, hey, you're home early
CarreraGTSCS's Avatar
I can't wait to see how this turns out. A DARE kit being turned into a scale masterpiece. This should be fun to watch.

Mike
Mar 17, 2012, 04:00 PM
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Scale masterpiece!


Quote:
Originally Posted by CarreraGTSCS
I can't wait to see how this turns out. A DARE kit being turned into a scale masterpiece. This should be fun to watch.

Mike
.....But not fun to do. Again, this will be a "fun" model not to the detail levels of my past efforts. So far, however, it hasn't been much fun.

I have had to reengineer so much of this thing so far, it's getting ridiculous. It's almost worse than starting from scratch as not only do you have draw and cut everything, you have to fit it to a poor design.

The plans show no detail as to where the cabanes or interplane struts go, so there is also no mounting info either. The large triangles at the end of the ctr section per the plans are completely superflous, esp w/ ply ribs. Small ones at the lower corners is a good idea however for more glue surface on the end ribs. I will be using CF rod in alum tubes to join the ctr with the outer panels rather than brass tube and steel wire.
Mar 17, 2012, 06:49 PM
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So you want to build a WWI biplane, huh?


The Camel is only the third WWI bipe that I have built and I thought it might me nice to share some of my hard earned lessons on these things.
  1. LIST=1]
  2. Use plywood for the ribs if you are doing a scale airfoil, just hog them out to save weight but, generally, bipes can handle the extra load. At the TE the ribs get very thin and you will wrestling the wings during covering.
  3. Think ahead and engineer in all your penetration points on the wings beforehand, even if the plans say nothing about it. I am referring to rigging, struts and floats. If there are scale details that you want to add, think about how you are going to install this stuff after the wings are covered. Is the rigging going to be functional? If so, hard points must be installed before covering.
  4. I like to thin CA my covering to the wing's framework, esp when it comes to going over undercamber. If you rely on painted on covering adhesives, I guarantee that the covering will pull away over undercamber as soon as you heat to shrink it and this is hard to fix.
  5. Prime covering with Minwax Polycrylic. Sure, nitrate dope works well but you need a million coats of it. Two thinned coats of Polycrylic will do the trick and is a nice primer for paint.
  6. I try to keep struts off the model until it is painted so I use alot of CF tube/rod that plug into points on the wings or fuselage. Nothing is more maddening that trying to sand, cover, mask or paint around a strut.
  7. Use carbon fiber/ply innards for struts with a balsa skin for roundness that is then covered with lt glass applied with thin CA. Extremely strong and light and, if you're smart, you will use the protruding CF rod/tab for your strut mounts. They will never break. A sanded CA/glass finish will never allow woodgrain to show.
  8. Engineer a little dihedral in the wings even if the prototype never had any - this avoids the drooping dog ear look.

.[/LIST]Anybody have any?
Mar 18, 2012, 11:11 AM
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One more bipe good idea


Forgot on my last post to mention an important one.....always plan to give covering somewhere to go. I see so many designs that have a control horn sticking up through the covering with no surrounding support to cover to. The covering simply can't just hang in midair around a hole. This is a biggie and a real pain in the neck if you don't do this.....Generally 1/8" is a good surrounding support dimension.
Mar 18, 2012, 11:36 PM
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Upper wing framing


I am 95% done with the upper wing framing which went fairly quickly but little of the "kit" was used here. Fitting the wing tips was the fiddly part as I of course did not like the design on the plans. This was made tricky by the intersecting spars and a by fitting special rib nearest the tip. After fabricating the tip, I simply lined it up with the plan's tip outlines and cut the tip and the spars to mate everything up. Easier said than done.

Although I faced the TE of the aileron bay with 1/16 sheet, the tedious part was filling in between the ribs top and bottom since the secondary spar goes through each rib and therefore did not give me any surface to cover to. Same goes for the root rib on the aileron and the corresponding long rib on the wing. Soft 3/16 sheet forms the LE on the ailerons.

Since I will be using my standard pin hinges, I pinned the ailerons to the wing to keep them in situ while I drill through for the hinges. This will be done with a long 1/16 drill, using a pc of ply support to line me up on the CL of the aileron. Always do this before the LE on the aileron is rounded out. If you are reasonably on the CL with your drill, this method guarantees perfect alignment with the wing and a true swinging door when you install the ailerons.

I also used 1/32 ply for the TE's with notches for ea rib as I hate sanding 1/8 sheet to a point as specified by the plans. Plus, tiny butt joints for ribs at a TE just don't work. The ply ribs held up wonderfully through all this.

Although this has been a bit of pain so far, I really like the lines of the Camel - it has always been one of my favorites.....
Mar 19, 2012, 04:29 AM
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Wing construction sequence


Since the only interlocking/locating parts on the wings are the laser cut TE's this is pretty much a "freehand" wing that must be built over the plans. By the time I got to the lower wings, I had the const sequence pretty much down - sliding all the ribs on two spars is the really only challenge here since they pull and grab, requiring all five of your hands.

My ribs mostly do not line up with the plans as asymmetrical spacing was used in the design, of which I am not a fan unless there is good reason. Here, I could see no good reason and I like symmetry. Plus, what I did is easier when drawing in CAD. The difference is not much so the plans rib lines can still be used to align each rib.

As I have noted previously, fitting the tip is a bit of a pain but we are almost there. It took me about an hr to do what you see here.....
Mar 21, 2012, 02:01 AM
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Hinging and other annoying things


With all (5) of the wing panels framed and sanded, it is onto installations. Hinges, control horns, struts and hard points for rigging - there is always alot of this stuff on a biplane and it is annoying to do.

I hate hinging with a passion so most of my designs use a lamination/core system for the fixed and movable surfaces with the pin hinge slots already cut into the core. This was not an option for the ailerons here and I have to install (12) hinges accurately. So, I made a tool to guide the drill through the LE of the aileron and the TE of the wing. The tool keeps the drill 90 deg to the LE/TE and the large ply plate's thickness was adjusted by adding balsa sheet to keep the drill on the center of the hinge line vertically. The drill is aligned by (2) 1/16 thick strips of bass capped with ply. Note that this only works if the aileron TE/LE are parallel.

For the strut and control horn locations, I made a hard balsa box from which sections are cut and installed to provide a slot. At the struts, a slotted ply plate cap is added for a rigging hardpoint.
Mar 21, 2012, 04:26 PM
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danrc's Avatar
Rob,
I love your work. The ribs look great, I firmly agree with you about the need for them to be ply. You see, a kit did you some good, it got you to design your own Camel =)!!!!


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