Bouwverslag Junkers Ju-87 B2 Picchiatello ⇨ W.Nr.0353 | 236 Sq. 96 Gr. Aut. B.

Hi Ramses,
This is an old thread but hope you still check it once in a while. Also hope English is OK.....
I am using your plan and building the plane but modifying it for an electric motor. I am doing some tests regarding the painting (new to me) and hope for some advice from you.
If I understand well, your process was:
- attach tissue with varnish
- one more coat of varnish
- one coat grey primer
- two coats paint
- final coat of varnish

Is that right?

I am trying to follow this process (but put on 2 coats of 50/50 dope / thinners first) but doesn't seem to work. I need 5 or 6 coats primer before getting a smooth surface to paint on. Any idea where I could be going wrong?

Thanks.

Fred.

 

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Hi Fred,

Welcome to this forum!
Great to hear that someone is building the Stuka from my Outerzone plans
Electric power should be no problem for the Stuka, but I can not advice you there since I'm an old school IC-powered rc-flyer



About the finishing of my Picchiatello (Stuka) in this build thread:

• At first the tissue is attached with clear WBPU (Water Based PolyUrethane).
• Second, when the WBPU was completely hard I`ve dry sanded the tissue lightly and applied a second coat of clear WBPU.
• Third I applied a grey WBPU primer and when hard, dry sanded thoroughly.
• Then I used "light-weight" filler to fill the down spots and wet sanded the Stuka overall with very fine grid sandpaper.
  
• After that I`ve added the panellines, external details, etc.
• When ready detailing, three different coats of WBPU were applied, the RLM sky, dark- and light green camouflage colors.
• Weathering was next, dry brush and different paint techniques used.
• Finally, the whole Stuka was given a 'two component' PU fuel resistant clear coat

All coats applied with different width brushes, no spray painting...



I use the 'one-component' WBPU right out of the can, no thinners (water in this case) were used.

The clear 'one component' WBPU is designed for flooring, to give a hard, scratch resistant top coat (Glitsa)
The colored 'one component' WBPU is a housepaint, they can make any color I ask, even scan a color chip to replicate (Karwei)
The clear 'two component' PU top coat is designed for the automotive/industrial branch, a very hard, scratch- and chemicals resistant paint (Nelfadur).

I`ve used this "one-, and two component" PU finish method on more of my planes before, and it`s well proven completely fuel resistant!



Searched for a good 'total finish' method after having too much of nice finishings being ruined by paints and clear coats reacting to eachother...
Found it in this WBPU total finishing method, which is also very cheap too,... just regular house paint.
Except for the 'two-component' top coat, it`s not the cheapest around.
Worth every penny though, when the finish of your model is still good after many years methanol/nitro spills on it, and all the exhaust fumes...
I`ve read about this kind of finishing big scale models in a magazine, I think Model Airplane News from a few decades ago!
Tried it myself and now it`s my favorite kind of finishing, but it`s just one of many very fine methods of finishing a scale model of course!



Do you have a build thread of your Stuka?
Which version of the plans are you building, original scale 1/8.3 or my design scale 1/10,5?
Please feel free to post pictures of your Stuka in this threat!

Cheers,
Ramses
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Hi Ramses,
Thanks for your quick reply. I am indeed using your scaled plan and have to thank you for the detailed and very helpful build thread. Also congratulate you on your result, think you built a great looking plane. Hope it flies well.

I am a beginner, this is my second scratch build plane and I am learning new skills at every step. Learning what works or not by trial and (a lot of) error. Therefore I am very slow and did not make my own build thread. Anyway I post some photos of my current status below. But don't expect any quick updates, I think it will still take me many months of slow progress before I am finished! At the moment I have mostly finished the fuselage and tail assembly. Now working on engine covers which I am redesigning from your plan to work with electric motor, ESC and a 4S 2800mah battery. So the front part of the fuselage looks a little different to the one you built.

Thanks,

Fred.

 

Hi Ramses,

Regarding the painting, thanks also for your great explanation. I tried to follow what you did as a trial using some scrap pieces of sheet 1.5mm balsa. I put the tissue (Japanese paper) on the balsa with varnish. Waited for drying then added another layer of varnish. But the balsa warped horribly. Almost became U shaped! Seems this did not happen to you........

I know you used WBPU but I could not seem to find it in any local baumarkt. I used Renovo 2 in 1 Treppen und Parkettlack (water based but not sure if PU or not). Could this be the problem? I tried a test again with Bondex Holzlasur fuer aussen (alkydhardz resin based). This time there was no warping but even after many coats I could still see the structure of the tissue. Any advice?

BTW what was the lightweight filler you used?

Thanks,

Fred.

 

Hi Ramses,
You can see in the photo what I mean. I did a test with two pieces of scrap 1.5mm balsa. On the right is a piece which had 2 coats of the water based varnish. It is reasonably flat. On the left is a piece which had tissue attached with one coat of water based varnish, then after drying another coat of water based varnish. Already you can see it has a warp.

Maybe not a varnish problem but instead a tissue problem? What kind of tissue did you use? What was the weight?

Thanks,

Fred.

 

[QUOTE = "Ramses, post: 3152612, member: 16039"] Update

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The plywood and balsa wood trusses, ribs and beams:







Construction can begin : D

Greetings, Ramses [/ QUOTE]
Hello if have started with this plans. Great work by the way. I am n nit unsure as to what parts are all balsa and what is plywood. If possible can you assist

 

Has anyone have more recent and updated plans of this current design?

 

Hi Fred,
Off course your thin test sheet is getting warped ... it's not part of a construction. I wouldn't worry about it. Shrinkage is part of the tissue's behavior, which you want to get flat and smooth surfaces.

 

Sure!
But which version are you building, the 10,5 scale (ca. 1300mm) or the 1/8 (ca. 1800mm) version?
I`ve modefied the original Royal/Marutaka plans in both scales, which can be downloaded for free from Outerzone.

This build threat is about the 10,5 scale version.
But I`m also building a 1/8 version, see this build threat.

The plans are modified kit plans from the old discontinued Marutaka kit, meant for scratchbuilding.
Hope these pictures help for the materials (balsa/lite-ply) used:

The 10.5 scale version:







...and the 1/8 scale version:







Have fun building yours!

Best regards, Ramses
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Thank you that helps a lot. I am building the10.5 scale. Is there any down thrust and or right thrust angle for motor mounting. I have a spare 2 stroke .46 lying around it should be more than enough power. What prop have you used on your plane and size?

 

I`ve build the engine on the hard-wood mounts, which have 0 degree down thrust.
Build in the engine slightly offset to the centerline, so the engine has a side-thrust of about 1 degree.

That must be more than ample power!
I fly mine with an old OS FS .48 four stoke.

Prop size I don`t know by head, I`m at my work now, will check that when I`m home tonight.

Cheers, Ramses
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The prop on the OS .48 FS four stroke in my Stuka (Picchiatello) is a Graupner 11x6 two blade:



Cheers, Ramses
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[QUOTE = "Ramses, post: 3152527, member: 16039"] .
@ Wouter, Bart and Femmo: The way I did it is indeed quite cumbersome and I could indeed have temporarily pasted the paper on the wood. I have now pinned the paper on it temporarily while 'tracing'.

@ Thieu: Many German war crates have also been used by other nationalities and can therefore also be made without swastika.

In the meantime I have cut / cut and sanded all wooden trusses, ribs and beams and the "short-kit" is ready. Also had a fuel tank that fits exactly in the hull and the OS 48 Surpass has been cleaned and checked and ready for installation.

Will post some photos tonight

Greetings, Ramses [/ QUOTE]
Morning what size and what make fuel tank did you use. I have a 8oz sullivan tank but is slightly large. And does not fit exactly.

 

Hi Andre,

Ik don`t know by head, will look tonight when I`m home.

Cheers, Ramses
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Hi Andre,

I`ve sent you a conversation.

Cheers, Ramses
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Hi Henry,
Thanks for the encouraging information. Build is going very slowly but I will proceed with the tissue method.

Fred

 

Hi Ramses,

Didn't have time to do anything for a long time on this build. Current status below. But now in lockdown. Maybe have some time to restart.....

Fred.

 

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Hi Fred,

Very nice work!

I would like to refer to THIS,THIS and THIS post in this build thread
This drawing is what I used for my Picchiatello:


Cheers, Ramses
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Hi Ramses,

Thanks for that! Let me see if I understand your process correctly and maybe ask a few questions. Is this what you did:

- Glued a strip of balsa to the trailing edge of the wing. (Maybe 1.5mm thick * 20mm or so wide?)

- Positioned the ailerons / flaps over the trailing edge of the wing and made notches in the trailing edge balsa strip where the support tubes would go (From the drawing I suppose the trailing edge of the wing aligns with the leading edge of the aileron / flaps but is maybe eg 10mm below it? How did you position the ailerons / flaps accurately when you did this? Did you eg cut some kind of template in order to get repeatability for each aileron/flap?)

- Temporarily glued the tubes into the notches with a little CA glue

- Then added some wooden support blocks (houten zadeltjes) under the tubes and fixed the tubes permanently to them for added strength (With epoxy glue? Were these just U shaped blocks or did you completely enclose the tubes?)


It seems from your dual Stuka thread you will do this a different way on this new build?

Thanks!

 

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Een artikel over de bouw van deze scratchbuild Junkers Ju87-B2 Picchiatello is in uitgave 01-2022 van het KNVvL magazine "Modelvliegsport" en het magazine "Drones & Modelvliegen" geplaatst:







Groeten, Ramses
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