Scratchbuild contest #2 AC-47 "Spooky" gunship

[Wrench66]

Here's another foam-sheet-special for your consideration.
Like many of you, I have a great love for the look and sound of any multi engined prop planes.....just the sound of the motors and props working in unison is enough to stir my soul....love it!
I had thought for a very long time about putting a twin together.....a bunch of different warbirds and commercial planes came to mind, but I never did it.

Until now....

I have been building this big girl (48" ws....my biggest yet) for approx 2+ weeks now and just today she took her first baby steps at the local schoolyard....to the cheers of approx 25 locals who happen to be watching from the next field over.
This is a strange kinda build log as I have the plane 90% done, yet to paint and primp, but am just now posting the build and pics. But follow along and I will post all the pics from the days past during the cutting glueing and assembling. The last posts will coincide with me painting and finishing. I will have the full plans and mods avail in the log as well.

Here she is as of now.....moments after her first 30sec check-an-trim flight.

thanks for looking in!

--Ray

[Wrench66]

Here we have our plans downloaded from Gene Bond's thread on RCG http://www.rcgroups.com/forums/showthread.php?t=343728 .
And of course our supplies!! I love a big bundle of FFF and Depron, hehe.

And we begin.....


--Ray

[Wrench66]

Originally Posted by Alpea42

If you fly it again tomorrow let me know . I'ld like a peek. You want some metalic silver paint or you gonna do it Army Olive with Victory Stripes. Gotta have those stripes you know. I know you'll be doing it as a Military C-47. So quit calling it a DC-3.

Sorry Al....how about Goonie Bird?? hehehe.....well, I HAD thought that folks were getting a bit tired of me building military planes SO I was thinking white with blue striped "United Airlines" livery circa '46.
But I have a real affection for a Vietnam era AC-47 gunship "Puff the magic dragon" replica from approx '68 or so.
Then again, a June '44 Normandy Beach Party replica would be ultra cool too...hhmmmmm...Gotta decide soon huh?!

Not sure if I can sneak into the school t'mora.......they're having some Christmas going's on in the morning.
I'll call ya if I do fly it though

A C-5?? NO, missed it! Not a common sight for sure, I think the last one I saw was at the Naval base upteen years ago

[Wrench66]

hhmmm, might be an option
I might just wait for Sat and the fairgrounds.......less lightpoles to deal with since this plane isn't THAT agile (by design). But CAN I wait?? I dunno.

OK more pics coming up.

[Wrench66]

The maiden went VERY well.......finally got her out in a BIG field to see what she'd do with some room to move (my schoolyard test area is really small) and I must say I am very happy with it.
A short motor run-up to make certain the two Turnigy's were cooperating with each other and the usual control checks.......a good burst of throttle and she's up in approx 8ft!
Enjoy the video and pics, the next time I post here I will have the normal build log and finally get some paint on (my birds have to earn their colors )
BTW....in the pic of the twin banking hard to the left you can just make out a little yellow spec of a plane in the shot.....that's Dennis' (TbigD here) Pico Cub cruising around in the stratosphere, a cool flier as well.

Anyway.....my twin lives, quite smoothly I might add.

--Ray

Twin engine RC airplane DC-3/ C-47 maiden flight on Vimeo

[Wrench66]

Originally Posted by artman51164

where do u get your foam from ???

Hi Art,
The blue stuff came from Lowe's out on Grove in Ontario. The white depron Steve got out of AZ somewhere's? PM him for the exact.

--Ray

[Wrench66]

Originally Posted by offtom

Looks very good Wrench. Love the full body look.

Made one of the profiles from the plans a year or so ago and enjoyed flying it then. Might have to make another one now.....

Thanks
I had mentioned to Gene last summer how I had thought of building his baby a bit different than he had drawn her originally. He let on that he had also thought of revising the plans to include a full fused version and maybe a different wing too. I just took that to mean he wanted to see it done

Lot's of little mods here and there in the build, all worth it for how nice it fly's. I will include everything I did different in the log.....stay tuned.

--Ray

[Wrench66]

As my first full fuse plane AND first attempt at a folded blue foam, airfoil wing (I have built lots of flat winged fliers) I did lots of looking around on Wattflyer to find all the info I could. Lots of different ways of doing almost everything......sooooo I decided to just press on and see how good I could do.
The FFF is what I used as it seemed a natural with the fold at the LE of the wing. I used a 1/4in hardwood dowel from my local Wally for a brace at the fold, inside the LE. Kinda helps the LE fold be just a bit "blunter" for a nicer slow fly attitude, just what I wanted with this bird. I added another 1/4 dowel at the 40% mark, CG, and this one was nearly a full span jobby. The wing is 48" tip to tip and the spar is approx 45". I used a mix of UHU Creative hobby glue and hot melt to join the folds into a soild wing. I used the hot melt to settle the spar inside the wing and the UHU along the edges as I assembled it. Now, a very interesting thing was occuring as I am merrily building this new wing......I have inadvertently put a few degrees of washout into my wingtips! Don't have clue how I did it, but there it is. Well, I read that wash-OUT was not nessisarily a bad thing, should help avoid those gnarly tip stall things I read about. hehe, rookie.
I had decided to not build any dihedral into the wing, quite opposite from the orig plans, as I wanted to use ailerons instead of the originals RET controls. Also, I could build the wing as one piece if I went without the dihedral.....OK done. Knowing though that without any dihedral I would risk my plane being a bit twitchy SPECIALLY because I had already figured it to modify it into a low wing model instead of the mid wing the plans called for.

I used 9mm depron for the 3/4 span ailerons for strength and light weight AND that size seemed a natural for the double thinckness wing. I used GWS CA hinges for them (another first use as I normally use 3M Bi-directional tape for the controls) as it made a nice clean assembly...for the controls I used Dubro 1/2A size control horns. These particular horns have a fairly tall top linkage hole that keeps me from over throwing the movements and making for a overly sensitive flier . I use a radio with no expo or rates (Laser4) so I have to be aware of the way I am building form the beginning as I cannot overcome anything with radio adjustments......makes me a better builder and pilot! lol
I decided 3/8in aileron movement would be good, if a bit conservative.

--Ray

[Wrench66]

Two more pics showing the bit of wingtip wash out I ended up with

==Ray

[Wrench66]

I decided to build a box type fuse since I was already set on not making this a profile bird (yeah, you heard it right GA ! hehe lol) and I had seen the box type done before on a few other planes. My plans show a profile/crutch type fuse, I went ahead and used the basic design outline for my project but soon deviated from it when it came time for cutting and assy. My other mod to this bird was to drop the wing down on the fuse to better resemble the actual plane. In doing this mod, I actually had chosen to do another in the same area......remove all but a degree or two of wing incidence. To explain, the orig plans are for a very light weight, quite floaty indoor type flyer. To this point, the orig wing was set at quite an angle.....for the slo fly undercambered type flying.....but since I was building a regular airfoiled wing I decided that I would attempt to remove all but the minimum of incidence. Maybe help the plane fly easier and faster without the two surfaces arguing (wing and horiz stb).
So without REALLY knowing what I was doing, scientifically, I cut a new saddle for the wing and did the 'ol TLAR method (That Looks About Right) and I drew a plumb line from the rear hrizon stab to the nose of the fuse and made my cuts with that as guidence for the wing's position.
In the same breath, I realized I wanted the wing to be removable also, so I made a pin and plate bulkhead and used blind nuts on the opposite side to cinch her down.

--Ray

[Wrench66]

Cut out the pieces for the tail assy, pretty straight forward procedure but I was now thinking that I will want a steerable tailwheel. The original configuration of this plane with require some creative thinking to make that work out, the rudder is quite a ways away from the bottom of the fuse

--Ray

[Wrench66]

Close ups of the wing attachment and servo tray with RX. Running the control rods back to the elevator was no trouble BUT being as the rudder is quite a bit above the servo placement I had to employ a couple of bends in the rod as it emerged from the plastic sheath. Good thing the rudder doesn't need 3D style of movement or it would not have worked out! hehe

[Wrench66]

First looksee at the wing and fuse together, all seems in order.

[Wrench66]

Now we move to working on mounting the motors on the wing. I chose the GWS style stick mounts for their ease of use and they are easily replaced in the event of an accident or motor change. The slots were cut in the lower wing panel to accept the 3/8in hardwood square stock in an "over/under" fashion were there is an inner stick used to tie the forward wing brace to the rear wing brace (at CG). Then the actual motor stick is CA'd to the inner stick making a strong, well braced unit.
This setup is a bit heavier than it could've been, but with a 48in wing and a estimated wing loading of less than 15oz sqin I think it'll be OK
I used Turnigy 2205/50 brushless motors with APC 8x6sf props, Turnigy 10amp plush ESC's wired together with a Y-harness into the #3 channel slot in my Hitec 04msg RX. These two motors have no trouble running together in this configuration, starting and running quite easily. I am using one Zippy 1000mah 3s with another Y-harness into both ESC's. I had thought of using a battery for each ESC, but didn't want to worry about one maybe reaching cutoff voltage before the other and causing some tense moments. I usually time my flights so I don't think it would ever be any trouble BUT I didn't want to take any chances! LOL

--Ray

--Ray

[Wrench66]

Check the short video of this modification below........ http://vimeo.com/2618524

The steerable tailwheel is a neat trick for this plane. I made use of two different types of these assemblies to come up with one, easy moving and semi scale unit. I decided to use the rudder servo control to activate the tail wheel. I used another push rod and used a small wheel collar to tie the tail wheel control to the rudder push rod. Turned out to work really well and is adjustable at the servo bay and outside on the steering axle via a grub screw.
I not only wanted control on take off, with a twin it's kinda mandatory, but I also wanted to WOW 'em when I landed and then taxi'd the plane back over to the pit area

--Ray

[Wrench66]

Keeping the scale aspect going here, I began to want some type of engine cowling. Something that would cover the motors and extend back onto the wing approx 1/2 way. I decided to use papertowel rolls and cereal box material to create what I wanted. I looked forever for the right size/style/shape plastic to make the cowlings to no avail......so, I made them.
I also took some of the lite weight spackle and water mixture and repaired the lower sides of my fuse where the wing had once been. Smoothed and sanded she looks great. Used the same spackle to smooth all the tail, engine nacelle and wing saddle joints as well.

--Ray

[Wrench66]

I used a discarded strip of 9mm depron as the basis for the wing saddle fillets. I first rough cut the depron to the length and width I needed, then with the wing mounted, I glued the strips to the fuse at the wing/fuse intersect. Using the upper wing panel as a guide, I glued the depron on with UHU Creative foam glue, a contact type that would "give" a bit on a mishap instead of cracking or shearing off completely in the event of an accident. When the glue dried enough to handle, I sanded the depron into it's initial shape and then used the lite spackle/water mix to smooth and finsh the rest of the way. Next is paint!


--Ray

[Wrench66]

OK, a little aviation history......the AC-47 was a variant of the orig DC-3 and the WW2 C-47 transport, but was designated AC for attack-cargo instead of the regular cargo C-47. The attack part was wholely provided by 3 deadly gattling guns.....called Mini Guns....hanging out two of the aft passenger windows and one standing in the side door entrance These monsters were capable of 6000 rounds (of 7.5mm ordinance size) per minute EACH! The most interesting thing about these aircraft is that in the 4+ years the AC-47 was used, not one protected village or site that they were assigned to was ever lost. The little dudes in the black pajamas even had standing orders early on NOT to fire on the "dragon" as it would only infuriate it further!!
The AC-47 "Spooky" or "Puff, the Magic Dragon" was well loved by all the GI's a**es they protected.....and desparately feared by all those on the opposing team (VC) below!!

Yeah baby.

--Ray

[Wrench66]

Up to date pics and video, fresh today, just before I took her over to the local schoolyard and flew her in the wind (approx 8-10mph today). I'll have more video avail when my Windows Movie mkr decides to cooperate.....otherwise, it flies even better now that it's painted...she likes it


build one, you won't regret it.......twins are seen as kind of a "black art" to make work well. Nothing doing, it's cinch and besides.....bet you won't see another at your field!


good luck,
Ray

VIDEOS===========

http://vimeo.com/2642210
and another from our field.....for some reason though you have to scroll down about 3/4 of the page to see this one. I tried relinking it directly to U-Tube but no luck!
http://uk.youtube.com/watch?v=k6eIVMzMaTo

[Wrench66]

Originally Posted by CHELLIE

Here you go Ray

DC3 scratch built twin eng. foamy electric RC

DC3-2 2nd Video scratch built foamy twin electric RC twin

Ah, much better......thanks again Chellie!


--Ray

[CHELLIE]

Hi Steve Hi Darylm Darylm is going to be building a Boeing 247 soon, Soooooooooo I have offered my help and recruited some help this is my friends Rays build thread on a DC3 very much like the boeing 247, and Ray did a Awesome job on it