Rieseler R III scale 1/25

[Anyun]

And the tail surfaces comes next. Covered with the same technique. The Rieseler has a tiny stabilizer, on the model it has been increased slightly in size.
In the last photo, you can see the small pieces of copper wire used as hinges for the elevator.
/Andrea

[OZPAF]

I'm joining the fan club of your ribs. Beautiful and careful work.

it's easy to see that this was meant to be a quick build

John

[Spiros]

Really impressive! Will my make 10,3gr Jodel Bebe (peanut) look like an overweight.....

Sorry to ask again but I did not understand what you use for hinging the ailerons. Can you please upload a pic?

[nickhawk]

Hello Spyros

Copper wire (συρμα χαλκου) 0,3 mm I suppose. It can be obtained from an old electric motor's armature winding.....

[Jmk89]

Hi Andrea

A few dumb questions:

• The photos seem to show a colour change between  construction and prepared for covering(or is it a photographic change only?)?
• Assuming you did this deliberately, did you colour the balsa so that it was a closer match to the intended colour scheme?  If no, then why did you do that?
• If you did change change to colour of the structure, what did you use to do it?

[TheLurker]

Hello Spyros

Copper wire (συρμα χαλκου) 0,3 mm I suppose. It can be obtained from an old electric motor's armature winding.....

And if you haven't got an old electric motor hanging about the wire cores from the ties for sandwich / polythene bags work quite well. Also around 0,3 - 0,5mm diameter. The paper covered ones are best, it can be a fiddle getting the cover off the plastic covered ones.

[Piecost]

Hi Anyun,

Thanks for the interesting thread. I too am an admirer of the Czech's fantastic models but have problems in understanding the text using Google translate on the minimakety.cz forum.

So, I really appreciate your demonstration of some of their techniques. I also enjoy viewing your high standard of craftmanship.

I have tried a variation on the sliced rib method in employing a blue foam core. Spanwise slots in the foam blank allow for accurate spar placement once the ribs have been sliced. The balsa rib caps are glued with aliphatic to the foam core, placed in their hotwire shucks and weighted to dry.

I applied tape to the balsa and glued the hotwiring shucks back onto the outside of the (unsliced rib blank). This helps it being propped vertically on the pilar drill. This is critical. I used a diamond cutting disk set 1mm above the base to slice the ribs from the bottom of the blank. See attached photo.

Isopropyl alcohol is used to melt the glue of the tape onto the balsa. This removes the tape and the remains of the shuck.

It is nessesary to put the sliced rib into a sanding jig to create a uniform and neat finish. A 63mm chord and 0.50mm (0.020") thick rib for a Peanut weighs about 0.018g.

I am not convinced that the foam core is worth using, in terms of weight or added construction time. But, perhaps, its added stiffness allows a slightly thinner rib to be used.

With regard to the covering; I have some questions:

Is the "Tengujo Kashmir" paper the same as "Gampi" Japanese tissue? This is available in a veriety of weights, but is very porous, as is the tissue you described.

Can you provide a photo of the container and label of the "Metylan" wallpaper paste? I would like to try to buy some in the UK to experiment with. I have read about this, imperfectly translated, on the Czech forum and have not really understood the products used or the methods. In particular; I have been trying to understand how Tonda tissue covers and fills the pores over blue foam to achive a smooth and resiliant surface. I got the impression that he fills the pores in the tissue before applying it to the model.

Tim

[Spiros]

Hello Spyros

Copper wire (συρμα χαλκου) 0,3 mm I suppose. It can be obtained from an old electric motor's armature winding.....

And if you haven't got an old electric motor hanging about the wire cores from the ties for sandwich / polythene bags work quite well. Also around 0,3 - 0,5mm diameter. The paper covered ones are best, it can be a fiddle getting the cover off the plastic covered ones.

It's also a nice idea. Since I'm now constructing my Fokκker D.VIII for CO2, I'm thinking of making the Rudder adjustable, until I find the correct angle. Not sure if such wires could hold the rudder in place due to CO2's power

[Anyun]

Since I'm now constructing my Fokκker D.VIII for CO2, I'm thinking of making the Rudder adjustable, until I find the correct angle. Not sure if such wires could hold the rudder in place due to CO2's power

You would need something sturdier than the 0.3 mm copper wire I used. Adjustable rudders/elevators can be a bit of nuisance because they can easily readjust themselves without your knowledge, causing "interesting" trim changes.

I made a sketch of how I did the hinges. The black parts are the wire hinges. First, the holes are drilled holding tailplane and rudder parts together. Then, an L-shaped piece of wire is superglued to the tailplane. After covering the parts, the rudder can be glued to the protruding wires. As the holes have been pre-drilled, alignment is guaranteed. The method is the same for rudder, elevator and ailerons.

[Anyun]

A few dumb questions:

    The photos seem to show a colour change between  construction and prepared for covering(or is it a photographic change only?)?
    Assuming you did this deliberately, did you colour the balsa so that it was a closer match to the intended colour scheme?  If no, then why did you do that?
    If you did change change to colour of the structure, what did you use to do it?

No dumb questions! Yes, I did colour the balsa structure to match the intended colour scheme. It prevents the stark white balsa from shining through. I used the PanPastel powder pastels. Only the surfaces in direct contact with the covering need to be coloured, this can be seen in the wing where the internal spars were left uncoloured. As the intended colour is light blue, I had to mix blue and white pastel. When I did the wing I used the raw blue first and then tried to lighten the colour with white pastel. This didn't work that well, hence the somewhat blotchy appearance. When colouring the tail surfaces I pre-mixed the pastels, with much better results.

[Anyun]

Thanks for the interesting thread. I too am an admirer of the Czech's fantastic models but have problems in understanding the text using Google translate on the minimakety.cz forum.

Thanks for your comment, Tim! The foam core rib technique is interesting and seems to work well. I must leave now, will answer your questions later /Andrea

[Spiros]

Thank you!

It's really clear now!

[Jmk89]

A few dumb questions:

    The photos seem to show a colour change between  construction and prepared for covering(or is it a photographic change only?)?
    Assuming you did this deliberately, did you colour the balsa so that it was a closer match to the intended colour scheme?  If no, then why did you do that?
    If you did change change to colour of the structure, what did you use to do it?

No dumb questions! Yes, I did colour the balsa structure to match the intended colour scheme. It prevents the stark white balsa from shining through. I used the PanPastel powder pastels. Only the surfaces in direct contact with the covering need to be coloured, this can be seen in the wing where the internal spars were left uncoloured. As the intended colour is light blue, I had to mix blue and white pastel. When I did the wing I used the raw blue first and then tried to lighten the colour with white pastel. This didn't work that well, hence the somewhat blotchy appearance. When colouring the tail surfaces I pre-mixed the pastels, with much better results.

Thanks, that makes it clear even to me

[Jmk89]

Since I'm now constructing my Fokκker D.VIII for CO2, I'm thinking of making the Rudder adjustable, until I find the correct angle. Not sure if such wires could hold the rudder in place due to CO2's power

You would need something sturdier than the 0.3 mm copper wire I used. Adjustable rudders/elevators can be a bit of nuisance because they can easily readjust themselves without your knowledge, causing "interesting" trim changes.

I made a sketch of how I did the hinges. The black parts are the wire hinges. First, the holes are drilled holding tailplane and rudder parts together. Then, an L-shaped piece of wire is superglued to the tailplane. After covering the parts, the rudder can be glued to the protruding wires. As the holes have been pre-drilled, alignment is guaranteed. The method is the same for rudder, elevator and ailerons.

With things like this, I tend to put a blob of balsa cement on the hinge asap after I think that I have found the right setting.  That tends to make it harder for a bump later on to lose the settings. 

If you need to move the  hinge later, balsa cement softens easily with a drop of acetone or general thinners. I have a small bottle of thinners in my flight box for just this purpose.  My initial trimming uses double sided tape to hold the packing in place, but once I think I have the settings right I stick all hinged joints and packing pieces to the underlying structure with balsa cement because:

• it dries quickly (although not as quickly as CA); and
• it is reversible using thinner (which CA is not, at least not easily).

(Gets down off JOD or Eric Coates soapbox).