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-   -   Comet Models Albatros DV (http://www.Wattflyer.com/forums/showthread.php?t=74387)

Bill G 08-28-2014 11:40 PM

Comet Models Albatros DV
 
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May as well have another "first" here, after converting the Comet Cherokee. I haven't found any other conversions of these models on the forums. Like the Cherokee, the die-cut parts for this model make Guillows die-cut parts look like laser cut. The Cherokee had a wing former that was cut partway off the parts sheet. For this model, they simply didn't give you any of the first fuse former. :Q

After cutting out the fuse parts, I figured setting up the prop/spinner assembly would be a good start. This is one of those "crank the heck out of the prop nut and don't ever break the prop, since you can't get in there again" setups. Amazingly with a bit of tape weight experimenting, I managed to balance the setup well, using CA behind the backing plate as the permanent balancing weight. The motor is a Heads Up RC 250 plus outrunner with GWS 7035 prop, which will tolerate 3s, at a bit less than full throttle. http://www.headsuphobby.com/Power-Up...otor-E-536.htm

Bill G 08-29-2014 04:30 AM

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With the tube frame construction, the front portion of the tube has to be cut away, to allow for motor mounting area. The method used was to cut the tube and temporarily reattach it with a sleeve, tack glued in place. After the motor mount box was fabricated, the front tube section was simply cut away from the front fuse former, and the tube's tack glue joint cut, finally removing the front tube portion. The motor mount plate was intentionally set a hair back further than needed, to allow for shimming to set the spinner to fuse clearance as desired. A 1/16" ply shim worked out well for adjusting that clearance.

Accurately lining up all the fuse formers with the Comet method of construction is a bit of a pain, but after the Comet Cherokee build I have a bit of practice. All the fuse formers are now on the the tube with the wing saddles also in place, and the remaining rear fuse former and keels are lining up well, with a test fit.

DEG 08-29-2014 04:35 AM

following along, waiting for glue to dry.....

riverrat 08-29-2014 01:11 PM

Subscribed!

pmullen503 08-29-2014 01:52 PM

Subbed!

Are you going to sheet the fuselage?

Bill G 08-31-2014 03:32 AM

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Quote:

Originally Posted by pmullen503 (Post 956131)
Subbed!

Are you going to sheet the fuselage?

Absolutely. Can't have it look like one of those cheap Maxford ARFs. :Q I get out of doing a painstaking natural stained woodwork job like on the Ansaldo SVA5, since this plane has a number of plastic parts that cover the top and front of the fuse. Lots of schemes to choose from. If I get really lazy, I can always do the all red one. :D

The fuse is a good bit of the way strung now, which was a bit of a pain since every other stringer joint had to be adjusted to depth to form a smooth fuselage curve, while CA gluing and then using activator. These old Comet die cut fuse formers are far less than laser-cut, CAD precise. If someone were to just glue the stringers in place using the formers as-is without adjustment, the fuse would be a warped mess.

Bill G 09-01-2014 05:21 AM

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Finished stringing the fuse and ran pushrods for the tail surfaces. After 100 or so of these builds :eek: I can usually map out the pushrod trajectories, drill the holes and slide the pushrods in place, maybe having to adjust a hole or two by just a hair at most. The tail surfaces were mostly built to plan, other than thickening the horizontal stabilizer from 1/16" to 3/32", and using a basswood spar for added strength. As on my last Comet build, the X-wing former design will be scrapped, since it would look awful on a vintage biplane, which will require new formers to be cut.

BTW, I was amazed to discover that someone actually built one of these things. There's no info on it, but I found the photo here: http://www.google.com/imgres?imgurl=...rt=127&ndsp=19

pmullen503 09-01-2014 02:35 PM

Nice. Where is the battery hatch going to go?

Bill G 09-01-2014 04:53 PM

Quote:

Originally Posted by pmullen503 (Post 956353)
Nice. Where is the battery hatch going to go?

Probably the best place to see the opening is the second picture, two posts ago, in the second bay forward of the bottom wing LE. The battery just makes it in place, with a bit of finesse.

Bill G 09-02-2014 11:37 AM

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Finished cutting parts for the redesigned parallel ran wing former construction, which will look a lot more scale than diagonally ran formers. The diagonally ran x-formers are larger than parallel ran formers, so I figured I may as well recut them into parallel formers, using the few straight ran formers as templates. I figured that since I paid for the wood, may as well us it, versus using my own sheet stock. Some of the top wing formers required a bit more effort, since the wing chord grows larger toward the tips. The former leading edges were also modified and notched to use 1/8" dowel rod for the leading edges. The kit supplies plastic molded wing tips which will not be used.

After a bit of study, I concluded that the bare bones photo on the plan must have been a prototype built from hand cut parts, since there are no plastic parts seen on it. The dies were likely then hastily made with some errors, and doubtfully prototyped. The plans show a plastic radiator that is not included, and I also noticed that the missing firewall is intentionally not included, and noted to be cut from ply, which was not included. I guess they want you to use the 3/32" thick fiberboard that they included. The same missing stock scenario goes for the wing TE stock, which was not included, although they supplied two extra main spars that are not needed. For the top wing radiator, I scored lines in a piece of 1/32" balsa which was then painted, which looks reasonable.

Bill G 09-03-2014 03:58 AM

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The top wing is now out of the way, and the bottom wing should be a good bit easier to construct. I almost pulled the wing from the board, without adding the 1/8" dowel rod leading edge. For the top wing, I managed to modify parts from the die-cut sheets to create all the formers, with the exception of two, which required using my own stock. Even the unused stabilizer parts were recut and used to create the wingtips. :Q Only the 3 wing center trailing edge parts and the 2 center airfoil formers were used as-is from the parts sheets, without being modified.

pmullen503 09-03-2014 05:48 PM

Much better than the X wing on the plans. What were they thinking?

Bill G 09-04-2014 04:58 AM

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Quote:

Originally Posted by pmullen503 (Post 956504)
Much better than the X wing on the plans. What were they thinking?

I question that also, especially considering that the wings can still easily flex and warp, where the tips of each X meet at. Definitely would look horrible on a vintage model also. :eek: Being on my second Comet Super Stars kit, it's obvious why Guillows keep going and they didn't.
Next to sheet the fuse, with both wings now finished.

DEG 09-04-2014 07:04 PM

Looking great Bill.....

thepiper92 09-04-2014 08:22 PM

Very nice build you got there. Interesting use of the roll tube, something I would never thought of using. What's the wingspan on this work of art? Where did you purchase the kit from, looks like something I would like to build. I've been looking at Manzano laser WW1 kits, not sure which would be better, or more complete. With WW1 planes, there are so many little details and I think a near full kit would be a good decision on my part.

Bill G 09-04-2014 09:54 PM

Thanks DEG

Quote:

Originally Posted by thepiper92 (Post 956590)
Very nice build you got there. Interesting use of the roll tube, something I would never thought of using. What's the wingspan on this work of art? Where did you purchase the kit from, looks like something I would like to build. I've been looking at Manzano laser WW1 kits, not sure which would be better, or more complete. With WW1 planes, there are so many little details and I think a near full kit would be a good decision on my part.

I would go with a Manzano laser cut kit, especially the Rake models, since they're efficient and robust designs. One of my favorite models is the Manzano Rake designed Bristol M1c I built some years ago, and flies quite well. This kit shows up often on Ebay, but has been out of production for ages. The main appeal of this kit, like Guillows kits, is that they do provide a number of detailed, molded parts, which would otherwise require some time spent to fabricate. Building these old Comet kits is somewhat analogous to the hippie that drives a 1968 VW Beetle that's certainly seen better days. It's not as if they can't afford something newer and better, but actually enjoy driving the unique Beetle.

The span of this kit is 28". Aligning the parts on the tube is a bit tedious, and either makes or breaks your fuse construction. The main problem is that they punched they holes a bit large, so that they do not have a slight interference fit. If made to fit tight, it wouldn't be so bad. I almost padded a few to fit tighter, versus trying to do a 3 hand task of holding the fuse formers in alignment while spraying CA activator, when you only have 2 hands. The one benefit of the tube is that you have a robust fuse which could likely survive a light nose-in that other models would not. Initially the concept was designed to encase a rubber band, which realistically this model is far to heavy for rubber powered free flight.

thepiper92 09-04-2014 11:08 PM

I definitely prefer robust, was just looking at a SPAD ARF at my LHS, 100 bucks, but the guy stated its a light built plane, and even though its a 36 inch wingspan, it can't take more that 6mph winds or so, which definitely stopped me from buying it. I see your point about the hippie comparison. There are a few Guillows kits at the shop, and even the boxes have a vintage look, despite the kits being newer as the boxes say laser cut.

Bill G 09-05-2014 07:59 PM

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Finished the fuse sheeting, given that the front sides and top do not require sheeting, as they are covered with plastic parts. Gotta love assembling and sanding the little eggshell plastic parts like the guns, manifolds, and pilot. I assembled and plan to use the plastic molded tailskid also, since it had decent bracket detail and overall appearance. The skid bar was reinforced with a CF rod and bent wire at the skid tip, that was glued inside one of the plastic halves, before gluing them together. A length of balsa stringer was also glued along the top inside edge of the triangular skid assembly, where it attaches to the fuse, for added strength.

DEG 09-05-2014 09:16 PM

Bill,

Been out of town for a few days (new grandbaby...:)). But am back now and have that Corsair ready for covering with microlite (it was waiting on my doorstep when I got home) as you suggested in PM.

Someone on another thread stated something about covering looking like a starved horse...lol I'm looking at the Corsair and also looking at your sheeting your model....I suppose you used 1/32" soft balsa for sheeting but what do you think you gained in weight as opposed to just covering your frame??

I'm at 10oz now (just bare air frame, no electronics, no wheels, no battery) ready for covering.

Bill G 09-06-2014 02:16 AM

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Quote:

Originally Posted by DEG (Post 956642)
Bill,

Been out of town for a few days (new grandbaby...:)). But am back now and have that Corsair ready for covering with microlite (it was waiting on my doorstep when I got home) as you suggested in PM.

Someone on another thread stated something about covering looking like a starved horse...lol I'm looking at the Corsair and also looking at your sheeting your model....I suppose you used 1/32" soft balsa for sheeting but what do you think you gained in weight as opposed to just covering your frame??

I'm at 10oz now (just bare air frame, no electronics, no wheels, no battery) ready for covering.

The weight difference between different grades of sheet varies widely. A lightweight grade of 1/32" could easily sheet that Corsair and add just a bit over 1/2oz, where not using excess glue helps also. The Corsair would definitely look good with sheeting.

Looks like it's that fun covering time now. :eek: I talked myself into adding collector pipes onto the kit supplied exhaust manifold, as it would look silly with only one collector. I plan to add the top wing radiator cooling pipes also, where one of them will house the aileron servo cable.

Bill G 09-07-2014 06:31 AM

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Figured I may as well finish the battery door before starting covering. Painted the little pilot also, although maybe not quite WW1 correct.

pmullen503 09-07-2014 01:48 PM

Very nice!

Bill G 09-08-2014 05:36 AM

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Thanks Pat.
Finished covering the fuse with Microlite cream, where the incredibly workability is quite welcome on a fuse shape like this one. While the size of the wing saddle on this model is not exactly scale, they kindly left out any details, and parts for that matter, as to how to finish it. Spent a bit of time cutting 3 precision formers undersized by 1/32" to allow for sheeting thickness.

The strut placement on the actual parts is not exactly to plan, along with them not exactly being scale in there respective positions. I took the liberty to modify them a bit, as well as creating the end struts such that the top wing will have more incidence and stall before the lower. At one time I didn't pay attention to those multi-wing details, and flew a Guillows Fokker triplane that had a constant roller coaster stall cycle. This model sets the flat bottom of the bottom wing at 1 degree positive to the stab, and thus the downthrust angle of a bit more than 1 degree set will probably be a good thing. The end struts were constructed to set the top wing at an additional 1/2 degree positive.

pmullen503 09-08-2014 08:08 PM

The combination of vacuum formed parts and sheeted surfaces look pretty good! Better than I would have thought.

I saw a Sterling kit of the DV of similar size at a swap meet over the weekend and I was tempted!

Bill G 09-09-2014 04:01 AM

3 Attachment(s)
Quote:

Originally Posted by pmullen503 (Post 956797)
The combination of vacuum formed parts and sheeted surfaces look pretty good! Better than I would have thought.

I saw a Sterling kit of the DV of similar size at a swap meet over the weekend and I was tempted!

I wanted to buy that Sterling kit from Ebay also, but ended up with this one. It's a bit different being a DIII, but the Sterling models are definitely higher quality. I figured this one would be really interesting, since I'm pretty sure it's never been converted to electric rc. On the other hand, the Sterling probably hasn't been done much either. The plastic surfaces really blended in well after painting. The mating seam barely shows up. I decked the mating seam down a bit with 150 grit, after gluing it to the sheeting, which helped a bit also.


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