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My story and the hunt for: Scale Foam , and DC 3 build

#1
Hello everyone!
First of all, let me know if I should be posting this thread somewhere else, I'm new to the forum and its ways.

I have been following FliteTest on YouTube for a while now. I started RC flying in about 2003-2004 with a 2 channel foam winged V-tail-ed plane, that gave me enough confidence to lose it in a huge gust of wind one day. When that was gone I bought the Typhoon 3D, and I still fly that one to this day. I haven't crashed it hard enough to quit flying it yet!
typhoon.JPG

After watching FliteTest for some time I wanted to build something myself from scratch. I tried 3d printing one of those spitfire or mustang models with the intent to make it RC, but I think it would have been too heavy. I watched some of the speed build videos and thought the FT Mini Tiny Trainer would be a great place to start. I bought a foam board display stand and printed out the downloadable pattern and got to work. I went through this one with the build video, starting with the chuck glider nose and simple wing, this gave me enough practice to finish the rest of the plane with great precision. I powered this one with an Eflite Park250 motor, a 800 mah 3S battery, and a 6x4.5 prop. I cut the motor mount and control horns from old credit cards with a small hobby laser. I tell you what, this plane flew so straight and smooth on the maiden you couldn't wipe the grin off my face. I still love flying this one.
BlackTrainer-airframe.jpg

After a few flights with the mini trainer I wanted something with a little more realism. I downloaded the plans for the mini corsair, and built that one in a few days time. I had a 2204 2300kv drone motor and got some small 3 blade props for it. The first flight was under powered, I think the esc wasn't set right for the motor I had. I put a different, smaller esc in and now it has about 3x thrust to weight! First flight broke a blade off the prop. Second, more powerful flight, I think the CG was too far back and it was too unstable for me to fly and broke another prop blade. I will add some weight to the front and try again this week.
corsair.JPG
corsair broke prop.JPG

Before I got to maiden the Corsair mini I wanted to start construction of a bigger plane. I looked online to see if anyone had plans for a DC3 type aircraft, I caught the tail end of the Plane Savers DC3 restoration and wanted to fly something like that. I hadn't found any complete plans yet so I set out to design it myself. I use Autodesk Fusion 360 for personal projects so its free to use, and I found some ways of designing flat-faceted models to make flat patterns. When I get done testing this new design I want to share it and see what other people are able to do with it.
Here's a little animation of the 3d model...

Here is the current status of the test build. I am trying to make the engine cowling from paperboard, similar to how the corsair was constructed. The motor pods use the same mounting as the mini corsair, so they can be swappable!
dc3-airframe.JPG

I plan to put some fixed landing gear on this since the motors aren't very high. Also if this works well I'd like to re-design it to have a round-ish fuselage like the corsair, for added realism.

Let me know if there's anything else you'd like to see on this new plane. I'm pretty proud of my progress so far. If I can get a friend to help I'll try to get a video of the maiden. The motors I think I'll push as far forward as I can to help get the CG forward, and the battery will surely go in the nose. If anyone has tips on if I need any thrust angle, or anything on getting something like this set up initially I'd appreciate the input.
 
#3
Update:
I was up til about midnight learning the tricks to model 'revolved' sheet metal type bodies, so the flat patterns can be generated with the wing slot already cut out. I was able to get the engine cowling started and a prototype cut from a file folder...

DC3-Cowl Modeled.JPG
A little help from the little laser cutter at the office (the rest of the plane has been hand cut up to here)
Cowl Laser Cut.JPG

cowl proto.JPG

I will be using some eBay drone motors, they seem to have enough pull.. MT2204 2300KV from Shenzhen (same as what I have on the Corsair) and I can either run both CCW or counter-rotating. The ESC's I have ordered are ZTW Mantis 12A. And I plan to run one 2200mAh 3S battery parallel to the two ESC's.

More updates to come.
 

BATTLEAXE

Well-known member
#5
Update:
I was up til about midnight learning the tricks to model 'revolved' sheet metal type bodies, so the flat patterns can be generated with the wing slot already cut out. I was able to get the engine cowling started and a prototype cut from a file folder...

View attachment 141532
A little help from the little laser cutter at the office (the rest of the plane has been hand cut up to here)
View attachment 141534

View attachment 141535

I will be using some eBay drone motors, they seem to have enough pull.. MT2204 2300KV from Shenzhen (same as what I have on the Corsair) and I can either run both CCW or counter-rotating. The ESC's I have ordered are ZTW Mantis 12A. And I plan to run one 2200mAh 3S battery parallel to the two ESC's.

More updates to come.
Love the DC-3's, flown in them many times as a kid with my grandfather as a pilot. So wanna see the maiden on this one. Great job
 

Mad_Mechanic

Well-known member
#7
When most people introduce themselves on this forum, they do so with a "hi, I'm new here, this is my history in the hobby."

They might also be in the process of building their first FT speed build kit.

But you have introduced yourself with a significant design and scratch build project that you have already made significant progress on.

This is very impressive and I love the work you are putting into this!
 
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#10
Update:
Didn't get much time this weekend to work on the DC, but I tried to get the Corsair to play nice. Once again it defeated me. I added a bunch of weight to the nose to get the CG closer to 1 inch behind the leading edge. It was still very twitchy. After review of the build video once more I think the control throws were a wee bit too hefty, especially on the elevator.
Capture.JPG
The crash didn't take the motor off, but I tried to throttle test it in hand and it shook the motor mount off and got the wires all twisted up.
So this motor is no good anymore, that's what spares are for! The motor cowl got a little chewed up too, but that's easy to remake.
I adjusted the throw in the radio to the 11° angle gage on the elevator last night, so this week I'll take 'er out and hopefully get some air time.

On the DC I was thinking... when building one, it takes about 1/10 the time to build a second one. If not to fly itself, to have spare parts in the field would be great.
Capture2.JPG

If the design is good enough to fly without major changes I'll surprise gift one to one of my buddies.
Here's what I have worked out for the powertrain...
Capture3.JPG
Basically 2x the setup that's in the Corsair, since it seems to have great pulling power with this ESC/motor combo. ZTW Mantis 12A and the ebay 2204/2300kv drone motors. Here I got a set with one CW thread and one CCW. I made a battery Y harness to go from Dean's T to 2x JST in parallel. I should be able to Y the throttle control wires since they are both set to output 5v to the receiver. I've seen jumpers that remove the power line from one of them but I don't know if that's entirely necessary. On a quick plug-in/throttle test nothing let the magic smoke out, so I'll call it good!

Next on the to do list on the DC is mounting the servos for the tail control, and possibly a battery cradle in the nose. Also wanting to steer the tail wheel, whether from another horn on the rudder servo or Y connect another servo dedicated to the wheel steer.
Then I'll be able to mount the wing for good and do some taxi driving! Still waiting on my tail wheel from ebay.

Thanks for reading, I'll keep the updates coming. To quote Scott Manley, "Fly safe!"
 
#11
Update:
Got some more parts to continue the DC# build, and have some cool graphics laid out, will see if my buddy can cut them in vinyl for me.

The Corsair flew! I placed the battery on top of the motor mount 'box' and banded it on tight. The CG was right at about 1" from the leading edge, maybe a little more. The elevator controls were limited at 11° with 30% expo.
The control felt really good once it got up to speed, and it does like to fly fast. Faster than anything else I've flown so far.
I flew circles for about a minute with a nice barrel roll in there for good measure. Touched down softly on the grass and thought I'd toss it up once more. I tried trimming in the pitch and roll while on the sunset side of the sky (probably part of my mistake) I lost my roll frame of reference and nosed it into the grass pretty hard...
Capture.JPG

As bad as it looks at first I think it is repairable to some degree. The break in front of the windshield is pretty clean and the tail control servos are still intact with control rods working. The wing was rock solid, just a small tear near the left wingtip that grabbed a piece of grass.
I'll work on this one for a little bit, and hopefully goes up in the next day or two. I learned a little from this, got a few experience points.

On the DC I am thinking I will put together a spare wing with a wider profile/ more surface area. If it needs to go fast like this corsair to be controllable I might have to go back to the drawing board.
 
#12
Update:
The DC3 model is getting the motors mounted to the wing tonight if I can get that done before I have to start dinner :D
I got a cheap Chinese tail wheel assembly from eBay. Though using the whole thing might be too clunky, I may be able to use the wheel itself and bend a different wire.


The Corsair damage was pretty simple upon a closer look. I glued the fuse back together where it cracked open, stuck the nose back at the firewall, but built a longer motor pod, to extend the CG forward more.
Here's the side that was split open, note the longer nose...
Capture1.PNG

There's a nice park on my way home from work, I was able to take er out for another test toast on my way home.
Capture2.PNG

I am finding out that this 3 blade prop might not work the best on this now nose heavy bird. Looking to see if there are any prop saver mounts that fit the 5mm shafted drone motor.

Here's a peek under the new front cowling...
Capture3.PNG
I made enough room here for the 600mah 3s battery right behind the motor. I can say in this configuration it flies great!
 
#13
Update:
The DC is a flying machine!
Here's a close up of the power section...
Capture2.JPG

I only have a short test video shot indoors here...

I have two 4x4.5 drone props, they are short but pack a nice punch. (and they are cheap as well, 8 pairs cw/ccw for like $3 at Hobbytown)

I had a chance to go flying this weekend, and big news, the DC flies!!!!
Capture.JPG
I had my buddy take a video of it flying but need to get that sent to me so I can post.
I epoxied a little Velcro strap inside the fuselage just in front of the wing to hold the battery down, so it sticks just past the plane of separation of the nose section. The CG feels a little towards the nose, but that is good. I think the wheels will need to be moved forward just a pinch to make ground movements easier... .It likes to tip forward and touch the props to the ground, (ooh look, a penny)

I started out by some fast taxiing on the dirt road, I don't have a tail wheel yet, just a skid, so as long as there's no wind or very small headwind it is pretty easy to control on the ground (had to increase rudder throw to make it steer better). After a few laps up and down the road I let it take a little hop, and it nosed down in the grass and broke one prop, nothing too bad.

I replaced the prop, waited for good wind conditions, then sent it! Like the Corsair it has little roll authority at low speed, so it flopped around a little until it had the speed to level out. Maybe bigger aileron surfaces might help this?

This thing screams along nicely once airborne. I tested out the center flap that I had cut in the center wing section, I have it on a 3 position switch, so there's an off, a mid, and full flaps. At the flip of the switch she wants to pitch up, so lowering the throttle brings it to level and she slows down keeping nice and smooth.

I ran a 3 cell 2200 mAh battery, after flying for about 8-9 minutes I brought her down and there was 45% battery remaining.

On the second flight I ran about 7-8 minutes and I had a little wing stall while turning around on approach to land, so she hit the ground pretty hard. All things considered there was hardly any damage, the nose section just popped off when it spat the battery out, so I'll have to re-make a couple of small tabs. And it broke a blade off each prop. It will live to fly again! I was surprised at how durable the whole frame is, it was a good test of strength and I don't think it needs reinforcements anywhere.

Before the next flight I'll change the wheels, and differential thrust might help with ground steering. And now that I know it works I can apply livery, here's a sample of whats going to the vinyl cutter...
Capture3.JPG

The Corsair flew nicely, I did hit the ground on my first toss, so I had to tape the front section back on. The 4x4.5 drone prop gets this plane going very fast!
 
#17
Update:
Still trying to get the video, iPhones make it difficult to send to someone that doesn't use apples.
I want to add a couple of strengthening pieces in the fuselage, and throw a little paint on before applying the graphics.

I got my second set of motors/esc's and more servos so I can finish serial 002.
Capture.JPG
I have the 002 wing assembled, with a little more 'spar' stiffening. I didn't feel the need to go overboard here since the wing 001 flew with hardly any flex, and the seam at wing bends held very strong (even through my little crash).

I ordered some 5030 3 blade props, (I wanted 3 blades on here from the start for realism)
Capture2.JPG
These get a little close to the nose section, but I think it'll fly.
This wrinkling and grass stain is most of the damage from the crash. I may double up some foam in this section too.

I'll keep the updates coming, and keep flying as much as I can this winter!
 
#18
Update:
Still trying to get the video, iPhones make it difficult to send to someone that doesn't use apples.
I want to add a couple of strengthening pieces in the fuselage, and throw a little paint on before applying the graphics.

I got my second set of motors/esc's and more servos so I can finish serial 002.
View attachment 145601
I have the 002 wing assembled, with a little more 'spar' stiffening. I didn't feel the need to go overboard here since the wing 001 flew with hardly any flex, and the seam at wing bends held very strong (even through my little crash).

I ordered some 5030 3 blade props, (I wanted 3 blades on here from the start for realism)
View attachment 145602
These get a little close to the nose section, but I think it'll fly.
This wrinkling and grass stain is most of the damage from the crash. I may double up some foam in this section too.

I'll keep the updates coming, and keep flying as much as I can this winter!
I've flown a plane where the prop was that close to the fuse, it sounded funny but it flew fine.
 
#20
Update:
The video recorded about a month ago, I finally got and uploaded!

He zoomed in about halfway through. There was a fairly steady breeze coming from behind us I believe. Unfortunately the video stopped right before my last turn-around and crash incident.

I did repair my gear, so next time the guys go to the sod farm I'm ready to go up again, next time with the 5030 props, and maybe some paint and graphics!