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Feb 19, 2016, 08:25 AM
Balsaduster
Thread OP
Build Log

Scale Build-Off 5 - Beginners 1/16 Fokker D.V Plan build


Hi folks.
I'm a newcomer in the forums as well as to the hobby in general. I've always loved RC planes and knew that building and flying RC scale models will be one of the hobbies I'll be spending my money on in my senior years.

Seeing as I'm in my mid thirties and halfway there, I thought I'd better get practicing. I've now finished and maidened my scratch built trainer - a 45" Papillon and desperately need another project to keep me from taking the trainer out in these 10+ m/s winds we're having.

In an effort not to draw too much attention from the Chief Financial Manager, I decided not to order a fresh batch of balsa and see what I can do with the leftovers from Papillon stock instead. The 25 1/2" span Fokker D.V fits the bill quite nicely.

I downloaded the plans from Aerofred.com, same as the Papillon and got to work. I am deviating from the plan here and there, to make due with what I have, so for instance, all 1/32 material will be replaced with 1/16. Also, since the plans are for a freeflight model, I'll be adding 3.7g servos for ailerons and elevator. That seems like a lot of added weight. But since I'm going to be running an electric motor instead of a gasser the plans call for, I'm hoping it will still fly in the end.

For the motor I've planned a chinese (I order 99% of the stuff used in builds from Aliexpress ) 1811X 2000kv 10g outrunner motor. Power source will be a 2S 800mAh 25C LiPo and a 10A ESC. Have a selection of props around the 5-7 inch diameter that should suit it.

Excuse the poor quality pics. I have not managed to figure out how to make the ipad mini take acceptable pics. Speaking of which - what does everyone use for taking the gorgeous pics I see in build threads? Do you people use actual cameras or do you just generally know what you're doing when taking photographs - unlike me?
Last edited by Thucar; Mar 06, 2016 at 11:22 PM.
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Feb 19, 2016, 08:29 AM
Balsaduster
Thread OP
I did not want to stick this in the first post as I expect I'll be making this types of posts a lot

I have a question. On the plans I see the wings go on using brass tubes and dowels. The concept remains a bit vague to me. Is it really just brass tubes epoxied in place and the wings have wooden dowels that press-fit into the tubes? No glue involved?
Feb 19, 2016, 04:06 PM
Registered User
ckimmey's Avatar
On a lot of free flight peanut scale models the wings are just held in by dowels. Usually with a rubber band stretched between them. It worked due to the lack of g loading on the wing root. It also could break away on a rough landing. You would probably do best to make the wings solid and for a model this size you won't need to make the wings removable. Make the root strong.
Feb 19, 2016, 04:13 PM
Registered User
ckimmey's Avatar
As for your question about pictures...I have been using my droid phone lately. If I want higher quality then I break out the wife's Canon EOS.

You have skills and the DV is a great subject.

If you have a Hobby Lobby nearby then you might be able to pick up a few pieces of balsa here and there "under the radar".

That's how I started my stack-o-balsa. Now I just place bulk orders with Tower Hobbies. They have good quality cheap balsa. Definitely worth the money.
Feb 19, 2016, 07:10 PM
Registered User
DustBen's Avatar
Quote:
Originally Posted by ckimmey
Now I just place bulk orders with Tower Hobbies. They have good quality cheap balsa. Definitely worth the money.
I've been a registered customer with Tower Hobbies since around 1986...

They give you the good balsa and I get the balsa cut from an oak-balsa hybrid!
-----------------
As for your rack of balsa in the picture... marry me! I'll cook and build models... you finance the scheme!
Feb 22, 2016, 04:25 AM
Balsaduster
Thread OP
Thanks for the feedback, ckimmey.

The bottom wing halves have been glued on. Used bamboo bbq skewers instead of brass tube/dowel combination. The same skewers are supporting the landing gear.

While I was making the landing gear I figured I'd do most of the wire bending and soldering all at once, so I now have the cabane and wing struts done. The bottom wing still needs strut hooks and then I can start aligning things up. I gotta admit, just the thought of the alignment process is enough to send chills down my spine..

But moving step by step I'm confident I'll get there in the end.

At this point I just could not resist popping the top wing loosely in place to take some shots.
Feb 24, 2016, 11:37 PM
Balsaduster
Thread OP
Been making slow progress on the plane. The weather has been calm enough to take the Papillon out most days for the past week. I'm pleased to see progress in my ability to land when I actually intend to. I'm starting to make sense enough of the planes behavior so that I've actually started playing with the trims.

The Fokker is slowly nearing the point of endless measurements i.e attaching the wings and tail feathers to the fuse. I'm wanting to keep the top wing off until the servos arrive, just in case I need to make any adjustments. I have 3.7gr regular servos as well as 1.5g linear servos headed this way and I have no idea which I'll end up using. I'm thinking if I can fit the 1.5g linears inside the wing, it'll be a lot easier to mask the wires coming down the cabane struts than it would be trying to hide the linkage when placing the larger servos inside the fuse.
Feb 25, 2016, 03:08 AM
Registered User
RadMulRot's Avatar
Great build!
Feb 25, 2016, 09:10 AM
Balsaduster
Thread OP
Thanks Moosivaras!

I noticed I had missed one small detail when bending wires - the skid pylon. So I ent that up and epoxied in place. Once the epoxy is dry (tomorrow) I'll be able to get started with attaching the tail feathers.

While waiting for the epoxy to dry I glued up the engine pieces to see what the total added weight will be. 16 grams - ouch. If I really cant make it work, I'll probably end up printing just the front halves of the cylinders, cut the intake manifolds in half and print everything with extra thin walls. Maybe a single 0.3mm wall.
Feb 26, 2016, 02:06 AM
Balsaduster
Thread OP
Ok, so there I was, peacefully sanding away at the top wing and ailerons and I got the most brilliant idea - "Since the pin hinges are quite bulky and the hinge blocks are small in comparison, why not drill the hinge holes before covering."

Well, there was a lot of cursing and fuming, drilling and cutting. One thing led to another, at some point AC was involved to make repairs to the hinge blocks...

Long story short - I now have ailerons firmly attached to the wing. The bad thing is - it still has ways to go before covering starts.

At this point I figured I'll be able to make any servo related changes to the top wing when its on the plane, so epoxied it on together with tail feathers. Another day of waiting for the epoxy to dry...

At this point the parts that still need to be built are the wheels, skid itself and the nose cowl. The plans call for a vac formed cowl but I'm going to try and build one using two 1/16 balsa bands and join them using a 5/8 balsa ring.
Feb 26, 2016, 07:09 AM
Balsaduster
Thread OP
Nose cowl is taking shape. Epoxy is dry and all components stay on the plane. The cowl will now need a balsa ply ring with magnets to keep it on the plane. And a lot of sanding.
Feb 27, 2016, 08:03 AM
Balsaduster
Thread OP
Once I had sanded all that I dared from the nose cowl, I still could not make the dummy engine fit inside. So it was time for plan B - printed it all again, this time 5% smaller and only front halves of the cylinders were used. This resulted in a good fit inside the cowl and the total combined weight of the engine + cowl is around 10 grams. A figure I'm MUCH more comfortable with, compared to the 16 grams of the earlier engine alone.

Time to tackle the wheels and the tail skid. Then I do believe she's ready for a thorough sanding. Hopefully once I'm done with that, the servos will have arrived so I can start working on setting up the control linkages. It will be pull-pull for the elevator and hopefully pushrods for the ailerons with servos inside the wing. (fingers crossed)

She'll be a 3 channel, with ETA
Feb 29, 2016, 09:02 AM
Balsaduster
Thread OP
The motor arrived!
It took me by surprise how small it actually is. I did the math twice again just to verify that it'll be enough for my planned 150 - 200gram AUW range. It seems the math checks out. Fingers crossed that reality matches the numbers on paper this time.

Did a quick weigh-in as well to see if I was on right tracks - the complete frame is 53 grams. Piled the engine, prop, ESC, two 9gram servos, dummy engine, the pilot and a 1200mAh 2S (She'll be flying a 650mAh 2S in reality) on the scale as well and got 130 grams. Looks like I'm in the clear as the servos I'll actually be using are either 3.7 grams and/or 1.5 grams.

Testing out some water soluble acrylic furniture lacquer as dope. Thinned it way down and put the first coat on. Waiting for it to dry so I can get back to sanding. I just wish the servos would get here soon. Can't wait to get the ailerons sorted once and for all - that's the biggest question mark for me right now.
Feb 29, 2016, 03:46 PM
Registered User
High_Start's Avatar
You have a great build going, doesn't look "beginner" to me. Keep up the good work.
Mar 01, 2016, 05:06 AM
Balsaduster
Thread OP
Thanks for the kind words, High_Start

Put the motor assembly together. The mockup engine fits perfectly, the 6x3 prop looks to be in the right ball park judging by the photos.

What I do not like, though is the prop saver. It just does not seem to quite center the prop so it wobbles a lot. The order went in for some "prop adapters" for 2mm motor shaft.

I'm considering trying to print my own spinner as well. The biggest hurdle is to draw it up in CAD.


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