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Old Apr 18, 2011, 11:20 PM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
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OST - One Sheet Twin - One sheeter #5 is a Beech 18

Well, I finally did a successful (relatively) maiden today, so I can start the thread. This one was a lot tougher to get right and keep on a single sheet. I'm actually not sure it still fits on one sheet after all the redo's to the prototype, but Hey, it's scratchbuilding, so almost a single sheet may be good enough.

The plane is a Beech model 18, with twin tails, and twin motors, AET, which made for some interesting design decisions. I decided to not try to add rudders, as they would have been very complicated/tiny mechanisms in a plane already more complex than other onesheeters. That led to setting up differential motor power, and more interesting learning for me. Still not satisfied that I've got that right, but at least I got two flights today with her.

Specs:

Wing span: 30"
OAL: 21"
all up weight (less Battery): 7.12oz 7.94oz after painting
Motors: HK 20gram 2300kv with gws6030 props (not counter rotating - yet)
ESCs: HK SS8amp
Battery: 900mah 2s Mystery
servos: 2 5gram Hextronix
Currently using a Vtail mixer for motor differential.

Finally weather cooperating, I got this video of the first flights after paint:
Beech model 18 The OneSheetTwin (2 min 43 sec)


I took a good amount of pictures during the build and will start a build guide in future posts. Here are the still shots of completed plane in "white" and finished.
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Last edited by springer; May 02, 2011 at 06:12 PM. Reason: added video link
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Old Apr 18, 2011, 11:28 PM
Registered User
MacBeth, SC
Joined Aug 2007
899 Posts
Danged Springer,

You just keep on keeping on. Absolutely love it. As a kid I had the hots for
Penny. LOL! Sky King was my hero. Can't wait to see it fly. Warm regards, Jim
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Old Apr 18, 2011, 11:29 PM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
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Templates/cut sheets

Here's the template/cut sheets in full and tiled format. Probably won't make any sense until I sort through and label the parts, unless you really like puzzles!
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Last edited by springer; Jan 22, 2012 at 06:21 PM.
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Old Apr 18, 2011, 11:30 PM
treefinder
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SE MI
Joined Oct 2004
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Jim: thanks, No vid yet, and probably not until we get some really calm weather, as she's a handful and I don't think i could vid and fly both at the same time.
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Old Apr 19, 2011, 02:41 AM
Build straight - Fly twisty
Whiskers's Avatar
Australia, QLD, Little Mountain
Joined Feb 2010
4,300 Posts
Man! That is a sweet little son of a Beech. (Well, someone had to say it)
It's really, really nice.

I just had a look at the plan, and reverently bow to the Master of Onesheetology.
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Last edited by Whiskers; Apr 19, 2011 at 02:48 AM.
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Old Apr 19, 2011, 09:18 AM
I'm flying ! (run for cover)
dtrip's Avatar
Greece, South Aegean, Thira
Joined Nov 2004
727 Posts
W..O...W...
I don't like exaggerations etc, but this goes towards the "genius" category...
Hats off man...
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Old Apr 19, 2011, 10:21 AM
treefinder
springer's Avatar
SE MI
Joined Oct 2004
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Time to start showing how i built her:
Print out the tiled file and tape the eight pages together. This will show where all the parts go on the sheet of DS foam. You will note that the top of the "page" in portrait view has two rows of parts all basically 2.25" wide, so you can cut each strip off the foam and then cut the details. The Fuse sides are simlar, except for the area between the tails, which is the top curved surface of the aft fuse. Don't cut that in half! As you can see in the third picture, I cut out the templates of the more complex parts and trace around them on the proper locations on the foam sheet. Since most lines are on two parts, you only have to trace once. Simpler ones, I just measure, draw and cut. Don't look too closely at the details in the pictures, as they are for the prototype and the final design cut sheet includes some reformatting and additon of parts I discovered i needed, but hadn't included in the original cut sheet.
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Old Apr 19, 2011, 10:21 AM
treefinder
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Fuselage: First, I cut the window and cargo door lines out in the fuse side template and traced them on the fuse side for later when they can be colored in. Also, trace the wing top surface lines to fuse sides, but don't cut them out yet.The first thing to glue together is the servo tray and two formers that will be at wing LE and TE. These are the tabbed and slotted pieces (Picture #1). When they've cured, glue the fuse sides to them, insuring that the sides line up with each other (kinda like gluing fuse sides to a monobloc). I use a machinist's square or triangle to make sure they are square to each other. Once that assembly is cured, tie the aft tip of fuse sides together with hot glue to form the taper in plan view. Glue the reinforcements to the formers (doublers actually for the top panels to glue to). Glue the nose top surface (note that it extends back to the former and tabs into a slot on it - figure #2). Glue the nose bottom surface in (I didn't, but I think you can also glue in the bottom surface under the wing at this point). At some point you will be trimming away the sides where the wing fits in and reusing that assembly to make the fuse bottom that is actually glued to wing bottom surface. I've added a partial former that should go mid way between the two full formers to add support to the fuse top surface that's not on the prototype. I'll add a pic to show it's location (the fuse top even though curved, sagged a bit so the former should help eliminate that). Curl the sides of fuse top and aft fuse top, trim edges to fit the fuse sides and glue them on (picture #3). You can get creative in fixturing it all as you can see from the picture. Last of all (for now) glue the windshield in place. I had a brain fart and did a split windshield before I realized that it should be the same curve as the fuse top with center basically flat (don't make my mistake!) If you need to, use bits of scrap to make the triangle side windows as shown in picture #4.
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Last edited by springer; Apr 19, 2011 at 09:03 PM.
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Old Apr 19, 2011, 10:24 AM
treefinder
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Wing: The wing is a KFM5a Undercambered with fwd 40% doubled and skewers gorilla glued into the LE . It's made in 4 parts (picture #1). curve and glue the step pieces to the main wing pieces in the two center (inboard of the motors) panels and the two outboard panels separately. I seem to have lost the pictures, but the panels are glued like other onesheeters, by taping the LE together, applying glue to the step, spritz water on the main wing, squeeze together, and fixture by laying on a wood strip and applying another board on top of sssembly and adding weights to hold them down for a good lamination. I did the two center sections together and the two outboard sections together to insure consistent bends. The joint between inboard and outboard sections seemed to work out to a common airfoil shape. Do outboard first and finess fixturing the inboard ones to match. Once these are cured, sand groove into the bottom layer LE and glue and tape skewers or dowels into the groove. I did a joint at the point of inboard to outboard connection and a joint at the centerline. With the doubling and curvatures, it all seems pretty solid. Once you have the wing done, you can check the final top surface to the lines traced on the fuse sides. I used a woodworkers curve checker to match the lines. Now you can cut the bottom out of the fuse and glue it to the bottom of the wing. Note the point to the front of the cut out to match the shape of the wing center LE. Picture #2 shows the bottom being glued to the wing bottom. If you glue the main fuse bottom to fuse before cutting it'll be easier to glue it all up (it was tough to align those little strips!) In final plans the fuse bottom glues to the insides of fuse sides, not to bottom as shown in picture. Picture #3 shows how it looks when done and sanded round. This picture also shows the nacelle bottoms in place and how the esc's are routed. Pictures 4-6 shows the nacelle glue ups. First make the main part from the rim, and three 2" dia. circles. Then glue the top portion of nacelles as shown and glue to main body. I aligned these assemblies to the wing, trimmed to fit and to make symmetrical and glued them in. Last I made the nacelle bottoms shown in Pictures #2 & 3 by rolling them to match the 2" dia main body and gluing the aft ends in place and rounding them. They were trimmed to match the wing bottom surface and step location and glued in place.
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Last edited by springer; Apr 19, 2011 at 09:49 PM.
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Old Apr 19, 2011, 10:27 AM
treefinder
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Final glueups and control surface setups: The tail assembly is glued to the fuse (I should note that the elevator is tape hinged to the H stab before the V stabs are glued to it). I used credit card for control horn, and cleared a curved slot in fuse tip for the control rod. An afterthought was to add the blue foam piece to spread the fuse tail to allow more room for the control horn and rod/zbend to "work". If you hot glue tacked the tip together, it's easy to cut through, insert the fff and reglue. I did that after gluing the H stab to fuse but it could be done as well when initial tip glued. Pictures #1 & 2 show all this. Picture #3 shows the servo mount and control rod routing.

Ailerons on the wing were cut out and hinged with tape after the wing was all glued up, as they run through the inboard panel to outboard panel joint. I used torque rods glued to the inboard ends of the ailerons, with wire loops soldered to inboard ends (picture#4). At this point I have no differential in them, but may add some to help with rolling into turns (particularly right turns). that will require curving the servo horn or making one with arm holes aft of the center hole. The tubes the torque rods run in are coffee stirrers (the ones with two tubes joined, figure 8 cross section)

The last two pictures show how the wing is retained to the plane. At the fwd end, it fits under a 1/16" plywood piece that locates and retains the LE at the skewers (that's why the cut out in fuse has the point) At the TE, a plywood shelf is glued to the fuse sides after a nylon 10-32 nut is epoxied to it. the ply piece on wing top surface has a hole through which the thumbscrew holds the wing to the fuse. I've cartwheeled the plane a couple of times and it all seems to be holding.
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Last edited by springer; Apr 19, 2011 at 10:17 PM.
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Old Apr 19, 2011, 10:48 AM
Just call me crash for short
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United States, OH, The Plains
Joined Jan 2011
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I have said it before and will say it now, You are the "One Sheet Master", and this time you have outdone yourself! Very nice build and the mind boggles as to what you will come up with next. Congrats guy! Very nice.

No way to mix the dif. throttle on the radio? I have put some thought into the dif throttle and it would seem to me that doing it on the radio would provide more direct control and easer tweaking than a mixer. My thoughts were to let the mixer do the servos (as it was designed to do) and mix the ESC's on the radio. Maybe it's just me over thinking things? Anyway, again, very, very nice build.
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Old Apr 19, 2011, 11:18 AM
treefinder
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SE MI
Joined Oct 2004
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I actually tried to do it with my Futaba 6ex, but couldn't figure it out. I could do a "master/slave" mix, but not with the throttle. The v-tail mixer does it, but I think I need to change either the endpoints or low rate percent to get the motors to change speed on command but not shut off. (that's the problem, if I move the "rudder" stick too far, the motor that's to slow will actually stop - not a disaster, but wierd) It's also hard to tell when they are balanced (for me at least, doing it by sound). I was able to get her to fly straight and level OK, so did get them to balance, and when turning with aileron/elevator, using "rudder" tightened the turn, and in fact compensated (i think, need more flight time) for the tendency to go nose up on Right turns. Another piece of the RC flight experience to learn! Keeps the old brain cells lubricated, I hope!
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Old Apr 19, 2011, 04:51 PM
TEAM HILLBILLY
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Pass Christian, MS
Joined Jan 2010
2,366 Posts
WOW! That looks awesome. Here's to the King of One ....Sheet that is.
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Old Apr 19, 2011, 08:13 PM
RC Adddict
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Canada, BC, Williams Lake
Joined Jan 2010
4,268 Posts
Springer that looks amazing nice job . Ive played with diff throttle a little as well and had varied luck . Theres alot of good info on it in the Twins thread .

After trying myself it really baffles me how you can all the pieces for something that looks that good onto 1 piece of foam .
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Old Apr 19, 2011, 10:10 PM
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Little Rock, arkansas
Joined Nov 2010
139 Posts
That is Awesome Springer.... If you're looking to do differential throttle... check out the TWINS forum... Ive built 2 twins and use a vtail mixer...differential throttle works like a charm.

Basically come out from both ESC's into the mixer and then from Mixer out to Throttle AND Rudder channel... If you want to use a rudder get a y cable and and plug the rudder servo wire into one end and the other wire from the vtail mixer. I found several mixers for under 6 bucks. I also made an adapter to use one battery for both esc's.... was no big deal either. Like I said... check out the twins... Foam and tape even made a youtube video showing how to do it.


#EDIT#

Sorry wilfor... I skipped right over your post and didnt realize you suggested the twins thread as well.
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