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Old Dec 28, 2009, 04:44 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
2,660 Posts
Build Log
Fun Build 3 - Guillow's Spitfire - She's Finished!

I've been following the wide variety of models being built as part of the Fun Build, and have been a bit envious, since I have a few models "under construction" , and I resolved not to start any new ones until I had cleared some of the backlog. The best of intentions were derailed by my two teenaged sons, who each gave me a Guillow's 400 series fighter for Christmas . Technically, both the Spitfire and Zero were designed and flew prior to the start of WWII, so my hat is now in the Fun Build ring. I'm going to start with the Spitfire and see if I can work my way around to the Zero before the end of the build-off. These models are especially well chosen, since I have the Hellcat and the Bf 109 already built in this series, and now each will have their historical adversary. What do you do with kids like that, eh?

There are zillions of Guillow's Spitfire builds here on the Zone, so mine won't be breaking any new ground. Warren Jones' build (visible in the Guillow's COnversion sticky) is jaw-dropping, and mine won't be anywhere near as ambitious as his. I'm thinking a standard four-channel T/A/E/R belly-flopper that tries to capitalize on the things I've learned building the Hellcat and 109. Built lightly, I think I'll be able to power it with my favourite IPS A drive, 7x6 GWS prop and 3s combo, and if I get really ambitious I'll swap out the IPS brushed motor with a Feigao 12mm inrunner for that extra oomph. I'm hoping for around the same 8 oz AUW I got with the 109, but it was only T/A/E, so I'll have to save a few grams during the build.

Wish me luck!

Steve
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Last edited by Steve85; Jun 27, 2010 at 06:22 PM. Reason: Successful maiden!
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Old Dec 28, 2009, 05:53 PM
It flew once before...
jofrost's Avatar
Northwood , New Hampshire
Joined Jul 2004
3,865 Posts
Steve ,

Welcome aboard . Not exactly what one thinks of when hearing the term "Golden Age" , but does fit the requirements

Good Luck , and watching your build with interest

-John
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Old Dec 28, 2009, 07:49 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
2,660 Posts
John,

Yeah, I would have liked to build Pat Tritle's 36" Ercoupe, but Dumas still hasn't released it . A man's gotta do what a man's gotta do .

Steve
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Old Dec 31, 2009, 04:55 PM
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WTFLYR's Avatar
West Central PA
Joined Dec 2008
2,140 Posts
Go Steve! Good to see you building this one.
I wouldn't worry about weight too much, as it has by far the most wing area of the series, at 1sq-ft. Mine is around 14oz AUW and feels like it could easily handle more weight. It was actually effortless to launch and fly, after determining what it needed, which was significant washout and right thrust. I may be motivated someday to give the plane the bl motor it deserves, versus the brushed-geared 350-C setup.

I understand Mitchell designed the Spitfire as an aerobatic plane in the 30's. I wonder if there are any schemes you could detail yours in? I'm not sure how identical it is to the war version, but it probably is very similar.
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Old Jan 04, 2010, 06:10 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
2,660 Posts
Thanks for the heads-up on the washout and right thrust; I'll make sure mine has both. I've thought about modelling either the prototype Spitfire or a Mark I (it had the unbulged canopy, two-blade fixed-pitch wooden prop and only four guns) in the spirit of the "Golden Age" theme of FB 3, but I'm leaning towards a Mark Vb in a North African camouflage pattern to pair with my Bf 109E "tropo". Decisions, decisions...

Anyhoo, having family visit between Christmas and New Year's unavoidably limited building time, but I managed to pick at the conversion just the same. My kit is typical Guillow's, meaning heavy wood and some inevitable die-crushing, but that's the nature of these beasts. I took a stab at cutting away the excess wood on the bare fuselage (no stringers) and managed to go from 16 grams before surgery to 10 afterwards. Some of this weight will be added back as I selectively reinforce places that need it, and of course the conversion will add its own bits to the overall weight. WTFlyer's comments on weight are welcome, though, as I won't worry excessively about saving weight as I have with some of my conversions in the past.

One place saving weight is always rewarded is the tail, and I've opted for lightly built tail feathers using laminated outlines. More to follow...

Steve
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Old Jan 09, 2010, 02:01 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
2,660 Posts
More progress to show on my Spitfire. I've focussed on finishing the aft end of the fuselage and tail feathers, and used Pat Tritle's method of fairing the tail surfaces into the fuselage with good results. Basically, the fairings are shaped as a unit, without the tail surfaces in place, and with blanks taking the place of the tail surfaces. Once everything is shaped nicely, the fairings are popped off (they're only tack-glued in place for shaping), the blanks are removed and Bob's your uncle.

I've strengthened the mounting of the tail surfaces compared to the plan by adding some medium-soft 1/4" sheet to the rear end of the fuselage to provide a more solid gluing surface.

Finally, I added a few more stringers to the fuselage to minimize the "facetted" look Guillow's kits can have, especially around tight radii like the top of the fuselage.

Steve
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Old Jan 09, 2010, 02:12 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
2,660 Posts
I finished the tail feathers using laminated outlines to reduce weight. The base of the vertical fin has a tab that fits snugly into a slot in the horizontal stabilizer to secure the two together as a unit, and the fairings are glued in place, further strengthening the joint. Hinges are small pieces cut from a discarded floppy disk and CA'd in place. Covering is Doculam.

I started in-filling the nose with some 3/32" sheet, most of which will be sanded away to achieve a smooth surface.

Steve
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Old Jan 09, 2010, 03:11 PM
Registered User
St.Petersburg, FL
Joined Feb 2004
1,345 Posts
This kit was the first tissue covered, balsa frame model I completed. I was about 12. It never flew, but hung from my ceiling till I went away to college. I recall being inspired by seeing the 6' .60 powered 10 Ch reed controlled Spitfire built by the son of the LHS owner.

Sure enjoying looking at the progress photos

sp
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Old Jan 09, 2010, 04:55 PM
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WTFLYR's Avatar
West Central PA
Joined Dec 2008
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Did you cut new parts? The wood looks too good for Guillow's wood.
The inset planking is really a good idea on these planes. On a Hurricane, it would be even more scale correct, but irregardless, getting the front fuse looking like a metal covered plane is what really matters. Our eyes tend to be drawn to the nose to cocpit area. If I had to take it over, I would have done partial sheeting on many of these planes, to avoid much of the nose ballast required. In the past I've preferred sheeting to inset planking, but that's starting to change. Once you get your technique down pat, it goes quickly and does not build the plane outward, throwing off cowl fit and overall scale.

After you finish this build, the Zero will be even more a treat. Mine should be flown more, as it is the best overall performer of them all. Mine has an apparently miswound GWS outrunner that causes ESCs to heat beyond the norm, so not wanting to risk the plane, it has been flown little. Lo and behold, I found a decent outrunner in my drawer last night that has the exact mounting pattern, size, etc. The Zero should be a "back seat of car" everyday flyer.
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Old Jan 10, 2010, 08:48 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
2,660 Posts
Sperry,

I've always wanted to build this kit, having built some of the smaller Guillow's and their WWI birds as a teenager. Glad you're enjoying the build!

WT,

The fuselage uses the kit wood, but the tail feathers are all new wood, since I used laminated outlines. This is a good thing, since my kit has the heavy wood Guillow's is notorious for. I'm a fan of inset planking for these birds too. It's a good way to strengthen the nose area without adding a lot of extra weight. That's great to hear about the Zero being a good flyer - it'll be a good match for my Hellcat.

True to my usual inclination to "improve" my kit-built models, I've decided to change the airfoil for the Spitfire wing. The one provided in the kit is a completely flat-bottomed airfoil with a leading edge that drops into a pointy "nose" flush with the flat bottom. Lots of guys have commented on the unsuitability of this airfoil for R/C, and I even modified the very similar airfoil on my Bf-109 to round out the flatness of the leading edge's underside. Thankfully, Guillow's has also produced an excellent airfoil with fine flying characteristics in their 3/4" scale Hellcat, and I'm adopting it for my Spitfire wing. I scanned the Hellcat airfoil and imported it to Profili, and then printed off a new set of rib templates, which I'll use to cut new ribs from light wood while I'm at it. I'll post some pictures next time. Ciao for now.

Steve
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Old Jan 10, 2010, 10:33 PM
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etotheo's Avatar
Saskatoon, SK.
Joined Oct 2009
224 Posts
Quote:
Originally Posted by WTFLYR View Post
After you finish this build, the Zero will be even more a treat. Mine should be flown more, as it is the best overall performer of them all.
Quote:
Originally Posted by Steve85 View Post
True to my usual inclination to "improve" my kit-built models, I've decided to change the airfoil for the Spitfire wing. The one provided in the kit is a completely flat-bottomed airfoil with a leading edge that drops into a pointy "nose" flush with the flat bottom. Lots of guys have commented on the unsuitability of this airfoil for R/C, and I even modified the very similar airfoil on my Bf-109 to round out the flatness of the leading edge's underside. Thankfully, Guillow's has also produced an excellent airfoil with fine flying characteristics in their 3/4" scale Hellcat, and I'm adopting it for my Spitfire wing. I scanned the Hellcat airfoil and imported it to Profili, and then printed off a new set of rib templates, which I'll use to cut new ribs from light wood while I'm at it. I'll post some pictures next time. Ciao for now.

Steve
I wonder what the airfoil profile is on the Zero... maybe something similar to the Hellcat?

Good looking build Steve!
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Old Jan 10, 2010, 11:17 PM
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West Central PA
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Originally Posted by etotheo View Post
I wonder what the airfoil profile is on the Zero... maybe something similar to the Hellcat?

Good looking build Steve!
The planes in this series have the same basic flat bottom airfoil, unlike the Dauntless and Hellcat. I did something similar with my Zero airfoil to the mod Steve did with his ME109 airfoil, in his 109 build thread.
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Old Jan 18, 2010, 08:39 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
2,660 Posts
Here's a couple of scans of the airfoils for the Hellcat and Spitfire. Like WTFlyer says, the 400 series Guillow's warbirds (Spitfire, Bf-109, Zero and P-40) all have the same flat-bottomed airfoil. I suppose this airfoil works reasonably well for rubber-powered free flight, but it apparently has some less-than-forgiving characteristics for RC. The 1000 series Hellcat, on the other hand, has a more refined airfoil with a Phillips entry (thanks to Konrad, I now know what this is ) on the underside of the leading edge. This airfoil flies very nicely on my Hellcat, so I've adopted it for the Spitfire as well.

Profili works great for this. I imported a scan of the Hellcat airfoil as a TIF raster file, used Profili to convert it to DXF vector format, and then was able to use the Profili editing tools to change the airfoil's thickness and then to automatically generate intermediate ribs for the Spitfire's elliptical planform. I didn't use Profili to add stringer notches, but I could have done so very easily.

While I was reworking the wing structure, I went from 22 to 14 ribs, as the Guillow's plan has a rib almost every inch of span, which is overkill even for a film-covered wing.

In the kit, the Spitfire leading edge is built up from three layers of 3/32" sheet cut to the elliptical shape, and to accomodate the thicker Hellcat airfoil, I had to add another two layers. I decided to notch the LE for the ribs, hopefully adding some extra strength with little weight penalty. Finally, the Phillips entry of the new airfoil necessitated blocking up the LE while the wing panels were being constructed.

On to the ailerons!

Steve
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Old Feb 28, 2010, 07:25 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
2,660 Posts
Woo, yet another long hiatus in posting build progress. I joked with crazysccrmd who's building this same kit here that I put the "pro" into "procrastination" . I haven't completely neglected the build, but as usual, work intruded, and a teen-aged son needed a little help with a science project, so at last, here I am again!

I joined the two wing outer panels with a custom-built centre section incorporating the single servo for the ailerons. It's positioned so that it ends up in the same fuselage bay as the two other servos, keeping all the heavy components close to the nose of the model. I decided on almost full-span ailerons to ensure good roll response, and built them from some 3/8" sheet. They ended up being pretty complex shapes, with their eliptical trailing edge and curving thickness profile from root to tip, but actually enjoyable to shape with a razor plane and sanding block. With Sullivan gold cables linking them to the servo, I have almost 1/2" of throw up and down, which I'm sure I won't need.

Steve
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Old Feb 28, 2010, 07:41 PM
The "pro" in procrastination
Steve85's Avatar
Canada, ON, Kingston
Joined Mar 2004
2,660 Posts
Once the wing was together, I could get back to the fuselage. With the new airfoil, I had to redraw the wing saddles and add a little extra balsa under the nose to match up the slightly lower bottom surface of the wing. Some soft 3/32" sheet infill allows most of it to be sanded off to provide a nice rounded shape.
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