Holland (oz15211)

About this Plan

Holland. Radio control glider model. Wingspan 3500 mm.

Direct submission to Outerzone.

Note for full build thread (in Dutch/German), see: https://www.modelbouwforum.nl/threads/wie-kent-dit-model-holland-van-c-van-der-schenk.287140/

Quote: "The Holland: As a real vintage Glider fan I am organized in the AMD/ Antik-Modellflugfreunde Deutschland e.V. (https://antikmodellflugfreunde.de/ is a vintage model association) and there I heard about the yearbooks of Frank Zaic. These books are a real treasure chest if you want to build vintage planes, especially the ones that were not kitted and not published as a plan. Frank Zaic did a wonderful thing for us by documenting so many planes all around the world, where he had great contacts to all modelers. A few yearbooks are still available as reprints and ideal to browse through again and again. At https://plansandthings.com/ I made contact to Jim Luecken and ordered them all.

A long time I spend with my nose in these books, but one plane was really to my taste, the Holland, designed & created in the 1950s by a guy from the Netherlands. His name is C. van der Schenk. The original plane had a span of 3,5m, so no enlargement was needed and the double vertical stabilizer gives the plane a very unique look in combination with the area of the vat.

In the last years I built & designed a lot of planes and many were gliders so, I could suffer from these experience and designed it with the help of FLZ-vortex and XFLR5. The real design was done in CAD and all Laser cut data came out there in the end. You can find these data here on Outerzone and build your own Holland, what would be a real honor to me if you do so, or just be inspired by the pictures and plans.

As the Holland had 2 small vertical fins, with smaller aspect ratio, my expectations on rudder reaction for a two axis plane was not that big, so I decided to implement ailerons. In history I did some ailerons in a very special way; the first plane with Aramid hinges was the Cirrus magic. I used this method on a few more planes and made 100% positive experience, ok. don`t speak about the building of it at this point :). The produced drag is much less than any other hinging version, due there are no grooves and no “blow through” air, nor any gap. You need less angle of deflection for the same results, and when the air passes by, turbulences are “low or no” ;-). Before coming to the difficulties let us focus more on the positive things: Another good thing is that the hinge is at the very low bottom, so the lever to move it does not come out very much on the upper surface, even good to minimize drag an what is most important in my eyes is that the Aileron is always exactly in position, because it is never separated from the wing during the build phase.

Now coming to the not so good things in building these parts: The complete building process needs a very good schedule before you start and you spend 20 times more work on these ones when you will do it for the first time. I never heard from any modeler building ailerons this way, but the Holland prototype is produced in 2 kits, the second one is presently build by a friend, Gero from Bad Bentheim, and I am curious to see how he will manage the aileron build. Hopefully later on we can publish pictures from both planes flying shoulder to shoulder.

Another thing to mention is the build of the fuselage especially the diagonal Aramid roving for super torisional strength and stiffness. OK Aramid did not have the strength of Glas nor the stiffness of carbon, but its ductility is necessary for the sewing process, to thread it through the spars. I spoke to Gero and he did this the first time on his fuselage and is very happy with it.

In the end there is not too much to say to rest of the construction, each flap has its own servo and building this plane goes fast due to the ready lasered parts, that I orderd at our local shop. During the build I made contact to Sebastian from the Netherlands https://www.rc-europe.eu/ and he said he likes to make a handful of laser kits, so interested pilots could ask there for help.

Last to say is that the Maidenflight was done on a day with best weather forecast for our local hill, but these guys who tell us, that we have earth warming in the next years are not able to forecast the weather of tomorrow ;-). So once I arrived at the hill, the wind was much less than forecasted and all other planes were grounded. From time to time my friend Herbert makes a try with his vintage glider 'Comeback' but the name was program and he was down soon again. Then came the point when I thought, ok. If we cannot stay in the air I will do one test round, just to know if its flying. My expectations lead to a 30 seconds flight, but it came totally different.

Once airborne from the small rubber catapult, switched in the middle hook, the plane was about 50 feet high. I had the calculations in the my memory just from the beginning it flies smooth, slowly, controllable and with a near perfect CG. I just let it glide with minimum steering and at the end of may be a hundred yards it was even 30 feet higher. Wow, didn’t expect that! Herbert and I, we were so astonished and this was just the beginning of a 30 min flight. You can see the Maiden flight here: https://www.youtube.com/watch?v=d6S9xUrz26s

Rudder reaction is good, glide ratio is perfect, recalculated with actual weight to 22,75! The minimum sinking is 0,31m/s. This are very good calculation results and the plane even shows this good result. When all others are grounded it flies, nothing more to say.

This maiden makes me so happy, cannot tell you in words, and now there is still a bit to do. I think the CG can move little more backwards, and the camera need a new white balance, so once looking the film our grass seems to be brow-yellow, oh dear. I hope to fly the Holland in the next time more often and will share here some more flying pictures.

The best flights are still in front of us, cheers Matthias."

Plan original size 100%.
Original by C.Van der Schenk, around 1950.
Redesigned by Matthias Möller in November 2023.
Weight 2960 gr / 16.5 lb.
Wing 3500mm Spw, 1 S3021 strak, setting curve non-linear 0-5°
Horizontal stabilizer SD 8020
Vertical tail HQ Oldy 0/12
Center of gravity 223mm from the nose at the wing connection, recommended starting point.
Glide ratio 22.75 lowest sink 0.31m/s (@2.96kg tow).
RC functions: aileron, elevator, rudder & tow clutch.

See maiden flight video here: https://www.youtube.com/watch?v=d6S9xUrz26s

Note the main planfile here is a single PDF file with 16 sheets. This serves as a quick overview. For a more detailed (itemised) view, see the supplement file "named_sheets.zip" for the same plan, but here each plan sheet has a title of material and size. Then of course there is the full CAD file download in DXF format. Steve.

Supplementary file notes

Named sheets zipfile.
FLZ Vortex data zipfile.

CAD file

This plan is available for download in CAD format.

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