36" Albatros D.Va

[Joe M]

I've been wanting a smaller plane to fly at the local park and after finishing work on the Sopwith Camel there's been a plane-sized hole in my free time, so I'm building one of these in park-flyer scale:


I like this Richard Flasher scheme, very medieval.


I'll be building directly from the Bob Holman D.Va plans, scaled down from 59" (1:6) to 36" (1:10). These are awesome plans, and I definitely recommend them to anyone thinking about building one of these planes.


Link to plans:
https://aerofred.com/details.php?image_id=97244


I've got five sheets of DTFB left in my supply right now which should be plenty for a plane this size, even doing formers/stringers and sheeting the fuselage. I'll glue everything together with Gorilla Glue (white) and hinge the control surfaces with CA hinges using Gorilla Glue.


The plans have rib profiles for scale construction as well as thicker sections for better-than-scale (especially at low speed) flying, I'll build the thicker sections and I'll build the stab thicker as well, because foam.

Tentative Specs:


Wingspan: 36 in
Length: 28.9 in
Wing Area: 328.3 sq in
Flying Weight: 800g (28.2 oz)
Powerplant: 370W BL motor
WCL: 8.2
Propeller: 9x4
Power/Weight: 210 watts/lb

Maximum Speed: 45mph
Endurance: 15 minutes on 4S 2200mAh



I know the battery makes no sense for that motor/prop combo, but it's what I have on hand. I'll have to trim the throttle channel on the radio with a power meter to make sure that it doesn't exceed 370W or 31A at WOT. I'll lose some throttle resolution, but 15 minute flight time isn't bad.

 

[willsonman]

Well, It's a Bob Holman plan so it should fly well but I suspect, as most of Holman plans go, you will find assembly of parts a bit less than intuitive. With such a small build I think some common supplies should make this one a breeze.

 

[Joe M]

A guy I fly with at the local club built an extremely detailed scale D.Va from the Bob Holman plans a few years ago and I really enjoyed watching it fly. He crashed it a few weeks ago which was what inspired me to build this. Here's hoping that assembly goes smoothly.


Started with drawing out the plans to scale.



I'll start with laminating foam layers for the lower wings -



- sanding them with a scrap plywood sanding block -



- and finishing up with some lightweight spackle.




Now to let these dry overnight and sand them in the morning.

 

[planebreaker2000]

Very cool technique for the wings.

 

[Joe M]

Thanks, I just sort of made it up. Didn't know how well it'd work, but I like the result.

Upper wing is next.

Laminated foam like on the lower wing.


Lots of sanding this time, much bigger wing. Thankfully DTFB sands easy.


Here's a photo of the airfoil section, surprisingly true to plans.



Now I'll spackle this and set it aside to sand tomorrow. I'll measure, cut, and hinge the ailerons and start the formers & stringers for the fuse tomorrow.

 

[Joe M]

Started work on the fuse today. I figured it'd be easiest to use the plan and profile views to generate four stringers and use the formers from the plans.



All together and ready for planking.



I cut a bunch of 1" foam planks to cover the frame. The plan is to get everything covered and painted first, then cut out an access hatch and install the electronics towards the end.



This is going to take a lot of masking tape...



so much tape...



This is a nice change of pace from my last project. The Camel took me about 6 months to finish, this should be done in a week or so



Extremely realistic Mercedes straight-six. I made an exhaust for it, too, but I'll glue that on after installing the top wing.

 

[planebreaker2000]

Good progress

 

[Joe M]

Thanks, planebreaker. I usually spend countless hours/days/weeks fussing over small details so my projects end up taking months to finish. This is sort of a speed run for me by comparison. The goal is to get this maidened some time next week.


Finished up the stab today and installed the lower wing.


The Bob Holman plans included alternate/optional enlarged horizontal and vertical stab profiles. I went with the slightly larger vertical stab & rudder and the scale horizontal stab and elevator. The scale horizontal stab is enormous on the D.Va as it is.



I made both parts of the stab from three layers of foam, with the center layer cut out so that the finished piece just slides over the back of the fuselage.



I mean, seriously, look at the size of that horizontal stab compared to the size of the fuselage. That is both true to scale and comically large.



This makes it super easy to align the rudder and elevator correctly.



After gluing I added a bit of foam to round out the tail and cut out the rudder and elevator from the stab.



I cut and sanded the hinge lines and reattached with CA hinges thinly coated in gorilla glue.



You might notice in these close-up pictures I rounded out the tail end of the fuse with some spackle. After all the practice from the wings and fuselage I felt I did a clean enough job on the tail that it wouldn't need sanding so after spackling I just kept on going.



Using masking tape as a guide I cut out slots for the lower wings going with +2° incidence as per the plans. The plans were disappointingly vague as to the exact lower wing dihedral, but a quick google search yielded +1° according to the unquestionably German "Idflieg Baubeschreibung fur Albatros D.V and D.Va Flugzeug"



I'll let the glue on the lower wings completely set up overnight before I flip that back over. Finished the night making some menacing machine guns from foam and bit of bbq skewer.




Tomorrow is paint.

 

[Michael9865]

Great progress, it looks amazing.

 

[rockyboy]

Very nicely done! Love the step by step instructions and pictures - thinking of trying some of these techniques out myself now

 

[Joe M]

Thanks, everyone! Got the painting done today. It's a rush job, but a decent enough rush job. I decided to brush everything because I didn't want to spend time masking and cleaning out the airbrush. Looking back at it this was a good time-saving decision for a model this small.

Started with drawing and cutting out stencils for the paint scheme, then traced the stencils onto the plane with a sharpie pen.




Everything was painted in craft acrylics diluted with floor polish. I kept the paint thin and used a single coat to keep the weight down. All finished the paint added about 12g (0.5oz)



I drew the radiator onto the upper wing to save time over making one from foam. I may add a foam header to it later, but I haven't decided yet since it'll get in the way whenever I want to lay the plane upside down.



Even with the stencils the tail was a lot more work than I had expected, but it came out pretty well considering.




Immediately after painting the nose I realized that I'd forgotten to account for right thrust in the prop/spinner. I'll have to revisit that later.



Such a menacing dragon.




I'm very grateful for the super simple "F F" designation, very easy to paint.




That's all for now, tomorrow I'll install the servos and control hardware.

 

[rockyboy]

Looks great! Very nicely done! I haven't heard of using floor polish as a thinner before.

 

[Joe M]

Thanks, rockyboy. I hadn't heard about using floor polish either until I got into airbrushing models last year. Apparently the best choice used to be "Future" but Pledge bought them out a few years ago so I use that. It gives a better finish than glass cleaner and I seem to get fewer clogs in the airbrush, but that could also be down to experience.

I got all the servos and control hardware installed today.



Started with chiseling out the control horns from 1/16" scrap plywood. I drilled with a 0.81mm bit and dremeled the horns to size.





I marked out the slot for the pushrod housing and aileron servo and then cut and installed everything. The ailerons share a single pushrod which is actuated from a single servo around the center of the wing. I placed the servo where the upper wing radiator would be so that I can possibly disguise the wires as the radiator pipe.



After that I cut out the access hatch for the fuselage. I'll hinge and latch this later.



I fashioned the servo tray for the rudder and elevator from scrap foam. It's not the most rigid thing ever, but it should do fine.



And lastly here's the installed control hardware for the rear surfaces. I painted the control horns and EZ links to match.



I'm really pleased with how the ailerons came out. Thick airfoil sections with aileron hinges close to the top surface meant that I could install very short control horns and having the rods rise up out of the wing makes the whole thing very sleek and low profile. I'll definitely use this technique in future wings.




Next up is power and electronics!

 

[Joe M]

Some progress and then some damage to report.

I cut out a round ply former to hold the shape of and reinforce the nose.


A hook and latch were added to the access hatch to make it easy to remove and replace.


I used to use magnets for battery hatches, but for $0.70 these latches seem like a no-brainer.


Installed the motor mount and ESC, all pretty straightforward.


A battery tray was cut from the same scrap plywood for a 4S 2,200. I attached it by gluing it onto the center stringers.


Aaaand then I messed up. I tossed a fresh Xoar 9x4 onto the motor and gave it a spin up with a power meter. Around 350W there was definitely a noticeable vibration, but I felt like a short test wouldn't hurt anything. I mean it's a Xoar prop, right?

So I ease the throttle up a bit. 370W, 390W, SNAP. The nose of the plane was torn off. It turned out the motor itself was either bent or unbalanced. I had just pulled it off of a crashed bird and neglected to check it before installing it onto a new one. Oh well, it's only foam. Time to start repairs!

 

[Grifflyer]

Awww I hate it when you mess up a nice bird, good luck on the repairs

 

[DamoRC]

Ouch! What a great looking plane.

DamoRC

 

[Joe M]

Thanks, guys.

The damage isn't looking so bad, the biggest issue is the loss of the motor. The only replacement motors I have available that'll fit will offer about 100W/lb of performance on an 8x4 prop. It'll fly, but it won't be quick about it.

On the positive side the flight time just went up a few minutes.

(edit: accidentally wrote 100W/kg, meant 100W/lb.)

 

[Namactual]

That's a bummer. :/

The build looks great though.

 

[Joe M]

Alright, finished repairs and made a spinner.


Here's the new motor and ESC. The previous ESC smoked out on me.



The new motor has a shorter can so I added a small piece of 1/2" sandeply as a spacer. The soft wood should also help absorb some of the vibration from the motor.



Some of the foam here was lost or obliterated so I had to cut out a new piece. Everything else went back together nicely and I was able to reinforce the area around and behind the motor mount so it should explode again.



With that done it's spinner time! I cut foam circles to size based on the plans and shishkebab'd them on a BBQ skewer to keep everything nice and centered.


After that I applied a generous amount of power drill plus sanding block.


And I ended up with something lookin' kinda like a spinner.


I glued in some scrap plywood onto the back of the spinner with small screws and cut out a back plate, it'll screw on and off like a normal RC spinner.



And here's everything back together. I balanced and painted the spinner and left a significant gap between the spinner and the fuse to allow for motor cooling. Doesn't look too bad for something made out of bits from the scrap bin.


There isn't a whole lot left to do now, assuming no more incidents. I'll do wing struts next, then bracing, and lastly landing gear.

 

[Joe M]

Top wing is attached.

I cut some really simple struts from strips of scrap 1/16" ply and tied everything together with 100lb braided kevlar cord. I used to be awfully intimidated by this part of the build, but with so many biplanes behind me this has become my favorite part. It's very satisfying how much stiffer and stronger the whole structure becomes after everything is tensioned up.





I still need to add the exhaust to the engine, the reinforcing "V" spars on the wings (I guess technically I could leave it as it is and call it a D.V), and the landing gear/tail skid.