FTFC21 - Seaplane Design & Build by Leaded50, Yokosuka 12-Shi Special Flying Boat (H7Y)

[leaded50]

i suppose (for first time) its possible i will participate with one plane of my list for a long time. Im soon used a year to gather info on the plane, and got some, but not all wanted. The Yokosuka 12-Shi Special Flying Boat (H7Y) from 1937-39 , a real mystery. The fact that our time has not reached any photos or explanatory drawing of the project. Referring to the authoritative sources: According to "Encyclopedia of Japanese Aircraft 1900-1945, Vol. II Aichi / Kugisho aircraft" , 1966), the project of a flying boat H7Y was so secretive that no one outside of this project does not knew about it, this is due to the lack of pictures and diagrams. There's also mention of the use of a flying boat diesel engines Junkers Jumo-205C, a few pieces of which was purchased in Germany in the late 30s. Japanese also carefully studied the German experience in the creation of a similar aircraft - flying boat Dornier Do-26. There's also the second volume Encyclopedia alleging four-circuit H7Y, in which the German Jumo-205C engines were installed on the Japanese boat in pairs in tandem, rather reminding scheme Dornier Do-26. Renowned aviation historian Tadashi Nozawa said at the same time that the Japanese project was a twin-engine scheme".
Reason for the project was to get a long distance plane, who could reach eg Pearl Harbor by air from Japan with eg. torpedos, not in need of fueling and/or carriers.
The plane was said to be too underpowered, and was buildt too light, and prototype and the project was closed after structural build failures eg. in wing..

This photo is said to be of the plane.. but it isnt veryfied. And its different opinon on how it was, 2 or 4 engines, where the wingfloats was,eg.
Its very unique with its wing style... and unknown mystery...... thats i like !


My plan is use what info i got, as the "Davis-style trapezoidal wing shape ", the bigger spinners than on the Dornier, twin-engine.... and follow some of the fuselage design from the Dornier, since its said had much recemblance. Sized approx 1000mm - 1200mm wingspan. Use two 2208 or 2212 motors. RC flying boat could be used on any ground/grass/snow/ water, that gives it a universality in where used.
Till july is should perhaps can make it

 

[leaded50]

working with the scetches , to decide the inner structure, formers,eg.. Top view is what is believed be approx correct, the stab and wing is in shapes that was used also by other Japaneese planes. Side view here is adjusted Dornier.

 

[leaded50]

ready made the plan for internals of fuselage. I will make horizontal, and vertical support to reinforce strength, and easyer straight in the build prosess. Horizontal will follow the assumed waterline, and will also be "the floor" for battery/reciver,eg.
Made out of the 3D view , adjusted for the 5mm foamboard use.

 

[FoamyDM]

A good start so far

 

[leaded50]

A good start so far

well.... i comed longer ive waited already some days since the entry... ha,ha

All the time when building totally from scratch an model never made before, it can show up some obstacles. The planned formers doesnt fit, or the main vertical/horizontal reinforcings spar dont fit with planned formers, and so on. Thats reason for start building together with the development of scetch/plans. Its easyer find what need be changed at the model, than on drawings. Theory and practical adaptation dont necessary goes together.
When making a seaplane, its also some extras to consider... what prop plans be used? Some seapray at take off can happend, easyer the closer to waterline they are. .. and that will ruin props, or at least ruin speed at take-off. That gave me here a reason to alter a little the gull-wing for even more clearance so could use even a 6" prop.
At least such problem can show up when building scale. 5mm error here, can easy be 1000mm or more on the original plane.

 

[leaded50]

Internals is constructed and buildt together as the model.

 

[leaded50]

i did forget check fully what wingspan it would be.....i eastimated approx 1000mm - 1200mm wingspan ... it got 1250mm.

Here is the two outer parts fixed together with the spars, and one side of nacelles in place.Frontspar have got a glassfiber reinforcing in full length cut as the wingspar.

 

[FlyerInStyle]

i did forget check fully what wingspan it would be.....i eastimated approx 1000mm - 1200mm wingspan ... it got 1250mm.

Here is the two outer parts fixed together with the spars, and one side of nacelles in place.Frontspar have got a glassfiber reinforcing in full length cut as the wingspar.

View attachment 197596 View attachment 197597 View attachment 197598

how do you build and make plans for these beautiful models?

 

[leaded50]

how do you build and make plans for these beautiful models?

From the "3D view" scetch, i can make internal "big fuselage spars" by making it 5mm smaller, and measure width/height on that, where the places are i want a former, and see shape.. then i have measures and shape on formers. Then make theat parts, glue it together... then its skins.
Allis done in similarity on "how i do it" in this post.: my-way-of-scratchbuilding-from-ground-up

Yes, i make "patterns" for plans when building here.
as here, the front part of fuselage nose. It will all be made to one .PDF file at endbuild.

 

[leaded50]

Here is how it was best build it. every part is sleek at connections, even at cutouts to shape it. Could done it in three parts that centerpart... but would got 2 more connection on the skin that will easy make minor disortion of shape... now i dont get it at all, just a smooth curb all way.
I made the centerpart of the three, done as two parts when building... for easyness of making shape at first. After done and glued on after also adjusting, it was traced to paper as one single piece that fits.

 

[leaded50]

i waas so "lucky" now.. when get next foamboard (last i had) , it was wrecked with wrinkles all over...that would say its rigidy isnt as wanted, and more difficult make smooth rounded skins.... and the delivery place is empty at moment, some weeks before on storage again + time to ship to me
Well, im using the "backup" and get another type locally (alufoiled one side and other self-adhesive) tear of the both outer layers so just paper back. More expencive, and more work to get a smooth painted outside.. but dont need wait for 2-4 weeks.
(need use car spray filler on outside and sand to make it best smooth)

 

[leaded50]

testing making a cockpit roof fit..

 

[leaded50]

the cockpit part is also the hatch for battery, eg..
Seems like get the shape done.... Some minor adjustments, and sanding for best fit against fuselage, this fits
This part is one of the things that are much unknown in detail on the H7Y, but know it had a flat frontal center window... and canopy/roof sloops against rear. Even a detail seen on other Japaneese bigger planes. And is not similar to the Dornier who is flat rearward, and have V-shape front.
Plans was to do the bottom first.... but at time, i did made some of the frontal skins of some scrap instead, since out of foamboard.

 

[FlyerInStyle]

From the "3D view" scetch, i can make internal "big fuselage spars" by making it 5mm smaller, and measure width/height on that, where the places are i want a former, and see shape.. then i have measures and shape on formers. Then make theat parts, glue it together... then its skins.
Allis done in similarity on "how i do it" in this post.: my-way-of-scratchbuilding-from-ground-up

Yes, i make "patterns" for plans when building here.
as here, the front part of fuselage nose. It will all be made to one .PDF file at endbuild.

how do you make your main spar. I want to use like a square spar, but my last former is too small for a spar. also, the plane I am making is suppossed to be similar to the ft commuter, how any reccommendations for making your style for that small, and plus I do not have a full size 3 view drawing.

 

[leaded50]

what ive done here, is using the "bottom fuselage spar only back some, and even build sides on it at front (eg. got a batterybox) and last part to rear is only vertical spar. At this plane eg. plan is making access to battery, eg from top (where canopy are) and to make a fully box shape isnt then needed , since top part cant be there for the access. As seen here:

Only way to know measures/shape on "vertical/horizontal spar" fuselage reinforcings, are to use a 3D view/pictures on such, resized to the measures you want your build to be.
By a square spar i always make it to fit the wanted to use battery inside, and formers /former parts outside of it, are used to shape the skins. When the square spare gets too big for the fuselage shape, its only ways, is either end the box shape, and use only vertical/or horizontal spar further, or make square box further shaped as a square funnel. This will anyway be more work/heavier than just use vertical/ and - or horizontal fuselage spar (specially if needs formers and skin outside) if not the fuselage is a square fit.

 

[FlyerInStyle]

what ive done here, is using the "bottom fuselage spar only back some, and even build sides on it at front (eg. got a batterybox) and last part to rear is only vertical spar. As seen here: View attachment 197846

Only way to know measures/shape on "vertical/horizontal spar" fuselage reinforcings, are to use a 3D view/pictures on such, resized to the measures you want your build to be.
By a square spar i always make it to fit the wanted to use battery inside, and formers /former parts outside of it, are used to shape the skins. When the square spare gets too big for the fuselage shape, its only ways, is either end the box shape, and use only vetical/or horizontal spar further, or make square box further shaped as a square funnel.

I wanted to make something as on the fortnitee plane in flitetests video spar, adn thought tat migght be a good idea. any tips on that, and on how to line up the squares?

 

[leaded50]

I wanted to make something as on the fortnitee plane in flitetests video spar, adn thought tat migght be a good idea. any tips on that, and on how to line up the squares?

This one? https://fb.watch/4Q7d27-O31/ , How its buildt is quite good explained there. What measures/plans used are unknown by me.... but as every other plane, it can be done with eg, just a picture directly from the side and top eg. Make both this in similar size, and use the techniques ive told. Even them did maked a open top box spar, and funnelshaped rear... '

 

[FlyerInStyle]

This one? https://fb.watch/4Q7d27-O31/ , How its buildt is quite good explained there. What measures/plans used are unknown by me.... but as every other plane, it can be done with eg, just a picture directly from the side and top eg. Make both this in similar size, and use the techniques ive told. Even them did maked a open top box spar, and funnelshaped rear... '

yes, like it. what I meant is I am confused how to plan out the box spar itself. thanks for your help though

 

[leaded50]

yes, like it. what I meant is I am confused how to plan out the box spar itself. thanks for your help though

somewhere you need space for the battery, either inside the box spar, or at underside. If inside, the box need be big enough space for the battery. A standard 1800mAh 3S is eg approx. .. 25 x 35mm x length.(at least one i got..))..that will give a box at 35 X 45mm + length outside. If underside, dont need this size if enough space around to outer skin. Its the same thing with the FT power pods, if planned for battery inside it needs a min size. Just think of it as a powerpod glued in. Where it should be vs formers decides by motor placement and thrustline to rear of plane. Normally FT uses much to make spar to fit lay the stabilizer on.

One of the best ways learn make planes, are make some of the FT ones, both square and "Master- builds" , that will give insight how it is, and their videos show how it should be done with very good insight, more than could be written easy. .

Box spar is decided by battery wants to use, and shape/measures of the plane outside.

In fact, by the Fortnite planes, its easy line up the plane in different views, and make a screenshot to get the 3D view.

 

[FlyerInStyle]

somewhere you need space for the battery, either inside the box spar, or at underside. If inside, the box need be big enough space for the battery. A standard 1800mAh 3S is eg approx. .. 25 x 35mm x length.(at least one i got..))..that will give a box at 35 X 45mm + length outside. If underside, dont need this size if enough space around to outer skin. Its the same thing with the FT power pods, if planned for battery inside it needs a min size. Just think of it as a powerpod glued in. Where it should be vs formers decides by motor placement and thrustline to rear of plane. Normally FT uses much to make spar to fit lay the stabilizer on.

thanks. will look into it. planning to use a 800mah 2s or 3s though.