Blériot La Vache (XXXVIbis) - WWI Dawn Patrol

[Ryan O.]

So to more or less copy paste what I said in the dawn patrol thread:
I’m a little late to the party, but since I was ahead of schedule for my FF’22 projects, and we all know that’s unacceptable; if you aren’t building at midnight the day before you leave you aren’t really embracing the spirit of Flite Fest and procrastination. I decided to build something for the 1/6 scale dawn patrol. I’ve always been in love with the cooky French WWI and pre WWII aircraft, especially some of the designs by Blériot. The XI looked easy to model and cut out in a weekend, but I really want to do the la vache (officially the XXXVIbis those who love Roman numerals and hate words), not for any particular reason other than it’s called “The Cow”. (Some of these are of the larger normal XXXVI)

And of course as a French aviaton pioneer from this time Louis Blériot had to have a suitably dapper mustache

Since I will have to leave FF late Friday, I may not be able to participate in the group flight but I may just end up giving the plane to someone to fly and keep since it’ll be really cheap to build either way. I could get enough info and pictures to make a model from these two websites, one in French (my worst class in middle school which I barely remember any of) and one in Russian (a class I definitely did not take in school and need google translate to have any idea what’s being said). Both seem straight out of 2003, but do the job just fine.
https://www.aviafrance.com/i/avion.php?ID=5728
http://www.airwar.ru/enc/other1/bleriotxxxvi.html

Specifications and other fun things:
Scale: 1/6
Wingspan: 1.7m
Length: 1.39m
Scale speed: walk
Likely maximum speed: brisk walk
Construction technique: master series because of how simple the curves are, and because the wing needs to be light
Ideal Power system: Power pack C because I’m irresponsible and who doesn’t love fireworks
Launch style: ground takeoff

 

[Ryan O.]

This is the best picture I could find of an XXXVI, although it’s of a different variant called Torpille. This helps a lot with the airfoil shape and general dimensions.

The only differences are in the tail feathers, wingspan, cowl shape, and number of passengers, La Vache is a 2 seater and the Torpille is a single seater. I’m going to have to stray from scale for the ailerons since wing warping and 9g servos don’t go too well together. The wing will be an under-cambered single piece of foam with either poplar or balsa spars underneath along with some twine struts. The wing joiner will be 3D printed and the fuselage will be master series with molded formers for both looks and weight, since the nose on this plane is more or less nonexistent. Balance is probably going to be the biggest challenge, but if I need to I’ll just fill the nose with weights, or if it’s really bad tape a wrench to it. I’m also considering using a different motor to the C-pack because a lower kv motor and the appropriate ESC from a place like Hobbyking would be much more responsible for the the same or even a lower price. I’ll probably do a motor around the size of SPONZ’s FT Scout XL so I can also use his motor mount. The landing gear’s also tricky, but I’ll likely do something similar to the FT stitch and the same as my Ford Flivver:

 

[Ryan O.]

It turns out that the website I used was wrong, and the scale wingspan is actually 2m (maybe, there's one source for and one source against, so I may just go for the shorter wingspan because it's easier. Anyways, I've got the fuselage formers and skins modeled, and let's just say it is not an exact science when you only have one side of a 3 view of a different but related airplane and some photos from the 1910's, but what I got out of it's good enough for my low standards. I actually found it useful to trace parts of other Bleriot planes, like the wingtip on the XI or the v-stab on the XXXIX, for similar parts on La Vache. I haven't got around to modeling the H-stab yet, but besides that, the internal structure, control surfaces, landing gear, and a few small cosmetic parts the outside, the model is complete. I'm debating making the wings skinnier too because the chord is too wide for scale. When I do make the plane, the rudder hinge will have to be reinforced because it's a huge full flying stab. I may just do something similar to David's monster Spitfire with the paper to paper hinge. I'm also going to try and find cheap triangle stock or dowels for the spars under the wing because triangles are cool and they'll disrupt airflow less.

I also put SPONZ's firewall from the Scout XL in the model to make sure everything fits, and I will base the internal structure off that.

 

[Ryan O.]

I saw this cool website called MyHeritage where you can colorize old phots for free, so I thought I'd give it a try with the photos of LaVache to try and figure out the paint job, and here's the results of a few:

The first and second ones are “enhanced“ so look a little weird but makes it easier to define where the v stab begins and the fuselage begins. It looks pretty simple, white with a bit of black or a dark metallic (the real one had thin metal armoring) color at the front, and "La Vache" is written in silver with a black shadow.

 

[Baron VonHelton]

Clear dope linen, which is a tan color......

 

[Ryan O.]

Clear dope linen, which is a tan color......

Cool, I’ll paint it that if I can find some tan spray paint.

 

[Ryan O.]

I adjusted just about everything to make the proportions look more true to the photos of La Vache. The rudder’s a little more square, the wingspan is back down to 1.7m, the chord’s a little narrower, and the fuselage is wider near the tail. I’m making progress on the internal structure, it has to taper a bit to avoid the cutouts for the pilot seats. I also ordered the cheapest possible power system, a $15 motor and a $10 40A ESC, what could go wrong?
[reserved for picture of plane when it catches on fire]

But that’s not why I made this post, the most important update is:

 

[Ryan O.]

All of the CAD is done besides the landing gear, so after I do that I'll transfer all the surfaces to inkscape and print out the plans. Because some of the formers are split in two by the wing, the skin will need to be glued on with the tabs still in. I'm currently planning on a top loading battery or batteries (depending on how light I can make the tail) through the canopy cutouts. There's also a chance I'll have to make the wing double thickness for extra strength, to stagger the seams, and so I can embed the spar in the bottom piece to keep the airfoil and looks as clean as possible.

 

[Ryan O.]

Sorry for the lack of updates, I reprofiled one of the formers and skins to make it look more scale and finished the extra details on the internal structure. I also made a wing former, and I'll probably put on several per wing. I'm going to try and stick with the single layer wing with thin wood spars, and the formers should help it keep its shape. I'm most concerned about the wings sagging on the ground actually, since the shape of the wing will make it strong under flight loads but on the ground it's nowhere near as strong. Safe to say there will be no inverted loops with this. The process of flattening out the skins with meshmixer and laying out everything in inkscape is underway despite a few bugs.

 

[Tench745]

I'm most concerned about the wings sagging on the ground actually, since the shape of the wing will make it strong under flight loads but on the ground it's nowhere near as strong. Safe to say there will be no inverted loops with this.

This is why the original had that truss frame and wires on top; holds up the wing.
Bit of trivia: most people refer to these as "flying wires", but flying, or lift wires are only the wires which take flight loads. The wires on top are "landing wires" and take the loads when on the ground.

 

[Baron VonHelton]

This is why the original had that truss frame and wires on top; holds up the wing.
Bit of trivia: most people refer to these as "flying wires", but flying, or lift wires are only the wires which take flight loads. The wires on top are "landing wires" and take the loads when on the ground.

Yep, and as I've already proven, fishing line is perfect & will save alot of repair work.

 

[Ryan O.]

Yep, and as I've already proven, fishing line is perfect & will save alot of repair work.

This is why the original had that truss frame and wires on top; holds up the wing.
Bit of trivia: most people refer to these as "flying wires", but flying, or lift wires are only the wires which take flight loads. The wires on top are "landing wires" and take the loads when on the ground.

Cool, I’ll do that with fishing line if it seems like the wings are floppy once I start building.

 

[Ryan O.]

I’m making steady progress on the plans, but it looks like I may not be at FF long enough for the dawn patrol flights, so if anyone will be there and can provide their own battery and receiver as those are the only two things I’m short on, the plane’s yours. I’d give whoever flies the plane the fake moustache too, but I already used it and giving it to another person would be, well, unsanitary to say the least.

 

[FlyerInStyle]

I’m making steady progress on the plans, but it looks like I may not be at FF long enough for the dawn patrol flights, so if anyone will be there and can provide their own battery and receiver as those are the only two things I’m short on, the plane’s yours. I’d give whoever flies the plane the fake moustache too, but I already used it and giving it to another person would be, well, unsanitary to say the least.

what batt does it take?

 

[Ryan O.]

what batt does it take?

My guess is 2 2200 3-4s in parallel to make a 4400, for balance purposes.