2017/2018 Balsa Build Along Dare/Brodak DC-3

[TexMechsRobot]

It's basically all buttoned up until I put the decals on it. It's got some issues (wing saddle, paint color matching, covering wrinkles, etc.) but I'm overall happy with it. I think it'll look great in the air so I'm excited for some dry, calm weather next spring.







I've decided not to try and fix any of the issues for now although that may change by the time I actually fly it. I was a little too trusting of the laser cutting by the time I got to the wing saddle since everything else had been perfect fits. Lesson learned there.

I still need to finish the details on the wheel struts, connect the aileron and flap pushrods, apply the decals, and do a final balance. Right now, it looks like I'll be able to balance it with the battery which is really nice. Not sure of the AUW just yet. I'll measure that after the decals go on.

 

[nhk750]

That looks amazing, I love the cowl flaps and the entire plane looks very scale. The wing saddles, maybe rework with some wing saddle foam? Not sure the fix there, but someone out there may have some ideas. It is going to be a great replica of the one at the flight museum.

 

[TexMechsRobot]

The right fix would be to cut the saddle off and rebuild it. I might be able to sand the high spot but that high spot is present the entire width of the saddle so that would be challenging and might not work.

I don't think it will create too much drag though so it's probably just aesthetics and I'm currently not bothered enough by it to fix it.

 

[Geeto67]

what are the saddles made of? if it is plastic maybe they can be reworked with a heat gun?

I know you put a lot of work into it, and it's a cool plane, but the nose cone and the windows bug me. Both are the wrong shape. Otherwise, great job!!

 

[TexMechsRobot]

Saddles are thin ply, balsa sheet, and balsa sticks.

Yeah the nose looks out of place and the color makes it a little worse. I may carve one out of balsa that is more parabolic and not a half sphere like the one provided. I think the windows are pretty close though. The paint not matching perfectly is worse to me than the shape.

 

[TexMechsRobot]

I plan to maiden on Tuesday, 12-December. I only need to install the push rods, get the balance right, and adjust my throws and sub trims. The weather that afternoon looks perfect (if not a bit cold). We haven't had rain here for quite a while and won't until the end of next week (which is a shock to have this much dry weather in December) so I'm hoping the field is dry and puddle free. The temperature should be in the low 50's so it shouldn't affect my battery performance, the wind is predicted for about 2-4mph, and the sun will be to my back in the afternoon. Doesn't get much better in my opinion.

If all goes well, then I can finish off the decals and cosmetic touches.

 

[nhk750]

I'm looking forward to seeing this beauty fly! I have been flying almost everyday this week at the school near my house and float plane at lake Desire and it's cold but good flying. I haven't been to our club field, but I'm sure it is good. See you Tuesday!

 

[TexMechsRobot]

I'm starting on the decals. These close up shots show you the worst of the covering. no matter how much I worked with it, the edges of the covering pulled in at different rates causing the edge to bend and wrinkle uncontrollably. I finally just had to stop and move on. If I had to do it again, I'd want to cover it in something lighter and more workable than Ultracote.

 

[rockyboy]

I had to do that kind of seam and patching on my Pacer with Solight and the effect was less noticeable - and what you've got there is still really darn good.

Your decals look dynamite too! Did those come in the kit or did you print yourself?

 

[TexMechsRobot]

The decals are from Callie. This is my first experience with her work and I'm impressed.

Thanks for the kind words! I was very frustrated with the covering when I was working on it but I told myself it'll still fly well and will look great in the air (which is where it should be anyway).

 

[nhk750]

Still flying today? I brought my T-Craft batteries to work so I can charge them.

 

[TexMechsRobot]

Yep. I plan to be out there around 2:30 or so. If you run a camera then we can a maiden video for the nice folks here on the forum.

AUW comes in at 2.3 pounds. For the size, it's pretty light but I've got serious concerns about the power to weight. Based on the static test I ran a little while ago. I'm pulling about 135 watts at full throttle. Divide that by 2.3 and I'm looking at about 58 watts per pound at WOT. I wanted it to fly scale but that may be pushing it a little!

I'm going too do a bunch of taxi tests first to make sure it can actually get off the ground. I do have the assistance of a large wing surface area and relatively light wing loading so we'll see.

 

[nhk750]

Sounds good, I'll be there around 2:45 ish. Sounds like it will fly "scale like".

 

[Geeto67]

AUW comes in at 2.3 pounds. For the size, it's pretty light but I've got serious concerns about the power to weight. Based on the static test I ran a little while ago. I'm pulling about 135 watts at full throttle. Divide that by 2.3 and I'm looking at about 58 watts per pound at WOT. I wanted it to fly scale but that may be pushing it a little!

I'm going too do a bunch of taxi tests first to make sure it can actually get off the ground. I do have the assistance of a large wing surface area and relatively light wing loading so we'll see.

So I have a question: In light of the plane being on the light side, was it a conscious decision not to balsa sheet the airframe? Or did the directions just not call for it?

The plane looks pretty great, but balsa sheeting seems like it would have solved some of your covering issues and also gotten rid of the "starved horse" look of the airframe under covering.

 

[TexMechsRobot]

It was done in an effort to keep it light. I agree that the full sheeting would have looked much better but it would have weighed a lot more. The instructions call for covering like I did. It is built in the style of "stick and tissue" models. The designer got his start by building and designing models for rubber powered free flight competitions and those things save weight anywhere they can.

 

[TexMechsRobot]

Good news and bad news.

Good news: The maiden went really well. It tip stalls to the right really hard but it didn't require any trim to fly well. I added some elevator trim to help but it wasn't necessary. It was gorgeous in the air and flew very scale like. It is under powered for sure but I could climb at full throttle and cruise at about 3/4.

Bad news: I stalled on takeoff on the second flight and crash landed pretty hard. I busted both nacelles and motor mounts and destroyed the left landing gear mount plate along with a few punctures in the covering. It's repairable with some moderate surgery.

Here are some before pics, the maiden video, and the after pics.

 

[nhk750]

It was a great maiden for sure. Sorry for the crash, but it is repairable and will look good as new afterword's. It looked like a real DC-3 in the video at a few spots.

 

[roversgonemad]

Great maiden. Bummer about the crash.... It had a great prescence in the air. It all looks to be very repairable. Congrats!

 

[rockyboy]

She looks great in the air! Bummer about the repairs, but it looks like it'll go back together ok.

On the stalling to the right, according to an article I was reading today (but seem to have lost the link too), it might be helped to add a little washout, perhaps an extra degree or so, out on the right wing tip. Not too much, but it should help with reducing the stall tendency a little bit.

 

[TexMechsRobot]

I think washout will help for sure. I think I can use the covering to shrink a little washout into the right wing tip to compensate for the right roll.

I've put this one in the garage for now as I work up the motivation to fix it. Because of the way it is assembled, it'll require pretty significant surgery to fix the landing strut mounting plates and I just don't have the will right now. All in all, the build went well and it was a smooth flyer. It really did look good in the air!