HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Mar 30, 2014, 01:57 PM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
9,577 Posts
Build Log
One sheet #15 Supermarine Spitfire Plans + Video

After an extended build and development period on the Rollason Beta, I got the urge to start fitting a plane onto a single sheet again (it's a worry - to use one of my Older Bro's aphorisms). This began as a 22" span half sheet based on the OSRacer lite I was trying to make as a small gym indoor flyer. Someone said it looks like a Spitfire with a bit of tweaking, and that got the juices flowing. As it turned out, the half sheet version didn't work well; I think it suffered from the same problem as original Beta, too small tail surfaces. Somewhere in the pain of trying to get it to work, I decided that perhaps a slightly larger version would fly better, and allow more room for servos, battery, etc. So, I expanded it to a full sheet, but since this happened about the same time we were discovering the MPF surface issues, decided to go up another size and use the lower grade MPF as a test case for it's buildability. The plane uses a 24x36" portion of the 24x48" sheet of MPF ( you might note that it scales down to 20x30, so might see future duty as a Readiboard plane...)

The good news is that she built fine even with the rough surface foam, and with the rolled fuse and carved nose block method, one might not even notice the roughness after sanding everything down smooth.

Maiden flight was last Wed (3-26-14) morning in 5-10 mph winds ( should take the wind gage out with me and be accurate!) Not dead calm, in any case which would be my preferred test conditions. First glide test almost perfect, first power on test a bit too much wanting to climb on power. Inside, and I noticed that "neutral" was actually a bit "up elevator". Fixed that, and shimmed the motor top screws. Second test flight was a treat! She glides well, power and control good, seems a well balanced setup. (much different from her smaller fore runner!) Got another session in yesterday morning and she performed just like maiden day, so I think I can go public with this design.

Specs: Wingspan: 35"
OAL: 28" with spinner
OAW: 8.6oz. less battery and spinner (this will grow as I am adding the filter/polycrylic covering)_
12.5oz with 1.3mah 3s pack
Motor: Emax 2812 1500Kv, with 7x6 apc style prop
ESC: 15-18 amp HK ss
Rudder/elevator: 5gm servos, Aileron:s 9gm servo

3-2-14 update:
Finished the filters, polycrylic and camo paint. Auw now up to 13.5oz less battery, 17.4oz with. for wing loading of 10.3oz/sqft. Won't be quite as floaty.
video up:
One sheet #15 Supermarine Spitfire (2 min 58 sec)
springer is offline Find More Posts by springer
RCG Plus Member
Last edited by springer; Jun 16, 2014 at 09:02 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Mar 30, 2014, 01:58 PM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
9,577 Posts
I really like the "taco shell" or rolled fuselage, as it makes the rounded top fuselage pretty nice looking and easy to make. In the case of the prototype, I discovered one small issue with the C grade MPF. I put the rough "grooved" side up, and when rolling with a bit of heat to help, I cracked the forward portion of the top curve. I got more careful with the rest, and managed to do the aft portion without further cracking. Word to the wise, put the rough side on inside of the curve! I added a skewer to the top curve right under the crack to reinforce and keep the line straight. It was just Gorilla Glued in and after wetting the skewer. The foaming glue locked it in well, and added more structure to the fuse top. The pictures show how the sub frame builds up, and the fuse wraps around it. I lined up the common lines (check the sketchup pics for which ones to line up)
springer is offline Find More Posts by springer
RCG Plus Member
Last edited by springer; Mar 30, 2014 at 03:36 PM.
Reply With Quote
Old Mar 30, 2014, 01:58 PM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
9,577 Posts
The wing is a slightly undercambered KFM5a airfoil. I didn't take many pictures of the buildup, but it's pretty much the same as other Onesheeters. The main wing halves and the under step parts are all curved with the camber to match the trim line in fuse outer skin. Then the main wing is wetted slightly (I use a tooth brush dipped in water), Gorilla glue applied to the steps, and the LE taped together as well as the ends. I then put the assemblies under some boards and weights to keep them aligned and tight together. It usually works...

Once the halves are cured, I sand the dihedral bevel into each and tape/glue them together with the dihedral. I used about an inch per side. You don't need any with the ailerons for roll control, but a small amount looks more scale (Looks much better when she's bearing down on you straight on, guns blazing! well, maybe not that last.)

I initially didn't use a spar either at the leading edge (my typical location) or at the step. However, the first flight showed that I really needed one! Variable dihedral to the max! Wings folded up about 2-3" per side in a relatively tight loop. The wing didn't break , but the effect was a bit too dramatic! I have since added a quarter inch square poplar spar at the step, which on second flight day proved about perfect for stabilizing the wing stiffness.
springer is offline Find More Posts by springer
RCG Plus Member
Last edited by springer; Mar 30, 2014 at 04:50 PM.
Reply With Quote
Old Mar 30, 2014, 01:59 PM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
9,577 Posts
Fuselage finishing:
The canopy is built up from the two forward sides, and front on the fuselage. It's a cut and fit situation here, most pieces will be beveled on one edge or another. The Bubble canopy portion is the extra piece that is glued to the fuse top surface, and then sanded down to form the bubble. Once it's all in place, sand and fill to get the desired look. Having several views of real planes helps here a lot.
Once all the pieces of skin, etc are glued to the fuselage, it's time to make the square boxy shape look like a spitfire! Basically, you just remove everything that doesn't look like a spit! (helpful isn't it?) Generally, I rounded the fuse just ahead of the canopy to about half way to nose, then sanded the valve cover bumps area by leaving some of the corners and rounded top surface between them. The bottom was just rounded as well as the taper to the spinner. mounting the motor and spinner will help with locating the taper in the nose.

The wing mounting is by tab into a ply receiver at Trailing Edge, and #12 nylon screw into a ply plate at LE. I used 5min epoxy to create the threads in the ply plate, and to reinforce the pocket in wing proper. Vaseline on the screw threads, apply epoxy to the predrilled hole, let partially cure, screw the screw in, let sit a minute, unscrew, let it cure. So far seems strong enough.
springer is offline Find More Posts by springer
RCG Plus Member
Last edited by springer; Mar 30, 2014 at 04:17 PM.
Reply With Quote
Old Mar 30, 2014, 02:00 PM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
9,577 Posts
Tail empennage:
The elevator is hinged to H Stab with some "scarfing" (actually a very open ribbon material that FB macdaddy found) it's retained with several layers of Polycrylic. Seems to work very nicely, and takes paint! Ailerons are hinged with same material. I did the Rudder with the traditional piano hinge type of packing tape hinge, as I had tapered both sides of the joint before thinking about the scarfing. Control surface hinges are credit cards, and the control wires (.032" music wire) run in coffee stirrers.

You can see the V bend for final length adjustment and modified Z bend at control surface ends. I use conventional Z bends at servo ends.
springer is offline Find More Posts by springer
RCG Plus Member
Last edited by springer; Mar 30, 2014 at 04:27 PM.
Reply With Quote
Old Mar 30, 2014, 02:01 PM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
9,577 Posts
misc:
The battery hatch was cut into the fuse after all shaping. I angled the sides in as I cut down, and angled the front and back edges forward as I cut down. The former shapes make the hatch locate and fit side to side, and the latter provide a lock in at front. The rear has a couple magnets for retention. The battery pocket was an issue with the prototype and I haven't figured out what to do for any Kit i might make of this. I located the foam part that is servo tray, and battery pocket bottom a bit higher that my batteries needed, so had to do some reconstruction. For the prototype, I cut away the area where I thought the battery should go, after doing a cg test with everything installed. (the battery needed to go further forward than I'd originally planned, wiping out the middle former top) and added 1/4" wide foam strips to subframe sides, then glued a new full width bottom to the bottom of them. Added strength and stiffness, but tedious to do after the fact. I guess it will depend on what battery pack one uses. A flat one will probably fit inside the original pocket.

I think that's it, if you have any questions, fire away!
springer is offline Find More Posts by springer
RCG Plus Member
Last edited by springer; Mar 30, 2014 at 04:41 PM.
Reply With Quote
Old Mar 31, 2014, 12:37 AM
Build straight - Fly twisty
Whiskers's Avatar
Australia, QLD, Little Mountain
Joined Feb 2010
4,218 Posts
Well! I see the rough foam was not a worry.
A very smooth machine indeed.
Whiskers is online now Find More Posts by Whiskers
Reply With Quote
Old Mar 31, 2014, 11:38 PM
Registered User
United States, IN, Fort Wayne
Joined Sep 2013
38 Posts
Awesome looking Aircraft. A real piece of art. Will you be releasing a kit for it?
Michael763 is offline Find More Posts by Michael763
Last edited by Michael763; Mar 31, 2014 at 11:45 PM.
Reply With Quote
Old Apr 01, 2014, 07:17 AM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
9,577 Posts
Eventually. I was hoping to get one ready for toledo, but need to sort out the battery pocket /servo tray thing. Ok for scratch builders who are gonna adapt anyway, but i figure i should get it right for a kit. Not that it will be too tough, but it is time to focus on getting the other stuff collected for the show at this point.
springer is offline Find More Posts by springer
RCG Plus Member
Old Apr 01, 2014, 12:13 PM
Registered User
United States, UT, Garden City
Joined Aug 2011
403 Posts
Sweet! just what I've been looking for. I just printed it off at 82% scale so that it will fit on a single dollar tree sheet of foam. I think that one of my CF 2805 2800 kv's should power it just about right!

Thanks Springer, this should be really fun. I'll build it with my kids.
gmwahl is offline Find More Posts by gmwahl
Reply With Quote
Old Apr 01, 2014, 10:14 PM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
9,577 Posts
Well, I'm glad I could provide it! Just finished the camo paint job. I think I will finish her with the trim from the Buckeye Don, a USAAF spitfire (amazing how the warplanes got shifted around and used by allied nations). As a Buckeye by birth myself, it just seems natural!

Found some Rustoleum spray paint at Home Depot today, that claims excellent coverage, and I have to admit that it does cover well. Found fairly close matches to the colors and it's only $3.44/can!
springer is offline Find More Posts by springer
RCG Plus Member
Old Apr 02, 2014, 01:33 PM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
9,577 Posts
First video up on first post.....
springer is offline Find More Posts by springer
RCG Plus Member
Old Apr 06, 2014, 10:34 PM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
9,577 Posts
Flight update after paint: i have flown her twice since the paint application, first on Wed. at metropark, second this morning behind the barn. The winds on wed, were gusty. And i needed th hold up or down to fly level. Fooled with trims and eventually broke a prop. No new ones so endcof flying. This morning, wind was calm, blue sky. I swapped in a 7x5 for original 7x6. At first i thought that it would be inadequate but some test flights showed it flew the plane just fine. 13 min on a 1300 mah pack! It dawned on me that of the 4 oz i added in paint to make it look accurate,at least 2oz were aft of the cg. So need to compensate! Fortunately, i can movc cg fwd by moving battery for ward. I had a sponge stuffed in nose pocket which i used as buffer and shift cg forward. I squashed it forward and got cg almost back to original flight. Last tosses were better than first. Back to a fun flyer! Larger aileron throws also helped with control in flight although takeoffs will remain at low rates. Got a bit squirrelly on takeoff.
springer is offline Find More Posts by springer
RCG Plus Member
Old Apr 06, 2014, 11:33 PM
Su-27's Rule!
Su-33's Avatar
Philippines, NCR, Pasig City
Joined Nov 2012
700 Posts
sub'd nice plane! any pics of the bottom of the wing?

edit: is this modeled after the griffon or merlin variant? i see conflicting details
Su-33 is offline Find More Posts by Su-33
RCG Plus Member
Latest blog entry: A cheap way to measure Kv
Reply With Quote
Old Apr 07, 2014, 05:50 AM
All can fly...Launch stronger!
ttersu's Avatar
France, Centre, Romorantin-Lanthenay
Joined Oct 2013
745 Posts
Subbed and dowloaded
ttersu is offline Find More Posts by ttersu
RCG Plus Member
Latest blog entry: My builds
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Found Durafly Supermarine Spitfire Mk 24 with Retracts/Flaps/Nav Lights abjets Aircraft - Electric - Airplanes (FS/W) 4 May 14, 2014 02:48 PM
For Sale Distressed/damaged kit: Sterling George Harris' Supermarine Spitfire jviss Aircraft - Fuel - Airplanes (FS/W) 3 Apr 18, 2014 05:15 PM
Sold Supermarine Spitfire Mk XIV Kit RCCombatGuy Aircraft - Fuel - Airplanes (FS/W) 0 Feb 23, 2014 08:52 PM
Sold Supermarine Spitfire Kit- 1/12th Scale NIB RCCombatGuy Aircraft - Electric - Airplanes (FS/W) 0 Feb 23, 2014 08:39 PM
Sold Durafly Supermarine Spitfire Mk 24 handyman 220 Aircraft - Electric - Airplanes (FS/W) 2 Feb 15, 2014 10:24 AM