1:3 Bohatyrew 'Motyl' of 1925

[ARUP]

The 'Motyl' (Butterfly) was built in 1925 to the design of Michal Bohatyrew at the Fachzirkel der Machinenbauschule in Poznan, Poland. It had a 10 meter span and was 6.7 meters long. Not much is known of it and I've only seen one photo and one three view. So... if any viewers from Poland or anywhere else have more information please correspond! I'd like to know what color to make it, too. If I could find out the most common butterfly in Poland and its color that might do splendidly for this 'Motyl'! Because of the scarcity of information my job is made a lot easier! I can build the model pretty much how I want. So long as the 'spirit' of the full scale is maintained I will be happy!

The first order of business was to start drawing the plans. The fuselage outlines are done using the three view and a foil was made in like manner.



That's all for now!
Dobranoc!

[gunny11]

Interesting subject.

[ARUP]

Thanks, Gunny! Just think... 1925!!! It looks more like a bat than butterfly!

[lenb]

Another gem from Jellyworks

[ARUP]

Thanks, Len! Since I now have a couple of good flying sailplanes it's that time to build a bad flying one! Let's hope it shines like a gem and doesn't fall like a stone... I mean... Charlotte! lol

[DennisB]

Michael, thank you for picking such unique subjects that are so cool and mostly forgottten,. We all get a history lesson with your builds. I am all the way subscribed!!

[ARUP]

Thanks, Dennis! I agree with your sentiment wholeheartedly! I liken these early birds' flying capabilities to toddlers' learning to walk. They fly and sometimes it is scary but they still need to be flown, at least as models, so they can be remembered. Those early designers showed the way kinda like 'standing on the shoulders of giants'. I keep referring to the ol' Vampyr but if this one flies 'weird' like the Vampyr I'll still be very happy. That thing handles so terribly that it is actually fun!

[ARUP]

Wood has been cut! The forward nose 'bows' will be 6 laminations of 1/16" hard balsa with CF tow and epoxy. The CF tow is needed to anchor the tow release. The side elevation of the fuselage plan was used to construct a 'ramp'. The nose bows get built on this ramp. The ramp is the fixture to set the up and down sweep of the bows as seen in side elevation. This pretty much has to be done (as far as I'm concerned!) because epoxy and CF tow laminates don't flex much and if these bows were built flat on the board it is difficult to tie them into the structure without undue stress. When this is done the bows will be sanded back fair to ~ 3/8" x 3/8" section. The rear portion of the fuselage longerons will be 3/8" square cross section.



The black weights holding the sheeting down until the glue dries. Laminates to get started when I get home from work.
Dzien dobry!

[ARUP]

Laminations started! There haven't been any lamentations, yet!



Two layers of balsa glued together as shown in the left hand portion of the picture. Its five components are in the right hand side. They are being built on 'the Ramp' but it doesn't show. I have to do more of this so not much will be 'picture-ized' in the near future because it is assembly line, boring, stuff.
Pozniej!

[ARUP]

The upper and lower nose bows are done. They were pulled off the 'ramp' and cleaned up with sand paper. The upper bow and longerons were put together today. The stab support and mount was started, cross members and diagonals were added and wing mount parts were fabricated.



Pozniez ziemniac!

[Gene C]

Looking good ARUP. That wouldn't be the dinning room table your working off of, by any chance?

[ARUP]

Hi Gene! Thanks! Yes, the hollow core door work surface hides a pretty pecan wood table. I'm a bachelor! Why... there's no telling what you might find and where in my house but it is clean and I make my bed in the morning!

Forgot to post a picture of the finished bows. More CF tow added then the wing mounts were epoxied, also. Reinforcements of 1/64" ply were glued to splices. Since the upper and lower bows with longerons are needed work was started on the lower version. The lower longerons have more curvature than the upper in side view at the 'belly' area of the fuselage just under the wing. The fuselage tapers toward the rear so with that in mind it seems an easier bending task if the curvature is cut into the wood beforehand. Two curved 3/8" parts were spliced onto the bow. Longerons will get spliced onto the ends of these when the glue dries. I will be relieved when the fuselage 'box' is built and built square and true!









Wiecej...

[ARUP]

Here's the rest...





Jutro!

[yyz]

The upper and lower nose bows are done. They were pulled off the 'ramp' and cleaned up with sand paper. The upper bow and longerons were put together today. The stab support and mount was started, cross members and diagonals were added and wing mount parts were fabricated.



Pozniez ziemniac!

Are you builddddding on the kitchen table???

Looks amazing by the way. Like the way you're integrating the carbon in with the wood. Very cool.

Mike

[ARUP]

Thanks, Mike! It needs CF because the tow planes are way too powerful for these draggy wind bags.

[Tom]

Are you builddddding on the kitchen table???

Looks amazing by the way. Like the way you're integrating the carbon in with the wood. Very cool.

Mike

He’s a single guy.....every single flat surface in his home is a building surface!😬

[ARUP]

That's right, Tom!

[lenb]

Are you builddddding on the kitchen table???

Looks amazing by the way. Like the way you're integrating the carbon in with the wood. Very cool.

Mike

No, thats the dining room table silly!!!

[Swiss1]

Watching the build as always Jelly, but I must ask what happened to the RRG Professor build?

Jeremy
SCCAAA TT TN

[ARUP]

Work to be done on Professor requires warmer outdoor temps.

[ARUP]

Witam ponownie! The lower crutch was built on top of the upper for symmetry. Marine ply is used at the end because the tail skid will need lots of support. The diagonals were reversed so they will match once the crutches are joined in their 'normal' positions. Time to block the crutches to the proper height and start adding the uprights. Sorry if this stuff is 'wordy' but for those that don't like it... too bad!



To wszystko!

[ARUP]

Wiecej! Big box building begun! The upper crutch was left inverted on the board and the lower crutch was blocked up over it. Bubble levels and squares were used to make sure everything stayed aligned as much as possible. A couple of verticals were let between the two crutches after the vertical ply tail parts were glued in place. More diagonals have to be fitted into the rear section and a tail post was glued in place. I hope to finish the rear part early tomorrow so the front section can get some attention.







PA pa!