Macchi 202, fuselage structure length

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MDriskill
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Macchi 202, fuselage structure length

Post by MDriskill » Tue Oct 19, 2021 11:37 am

A long shot for you Regia Aeronautica experts...! I'm working on the vintage Hasegawa 1/72 kit of the Macchi C.202 Folgore, and would appreciate input on the correct length of the real machine's fuselage, specifically the length of the main structural "core" assembly, from the firewall to the rudder post (image from Maurizio di Terlizzi's superb "The Macchi MC.202 Technical Guide" in Valiant's "Airframe Detail" series).

Image


The diagram below is a C.205 Veltro (image from a great article here!). The dimensions are reputedly from factory documentation. The core length is shown as 5210 mm (dark red text additions are just my notes by the way):

Image


BUT...all don't agree on this dimension. The two best sets of scale drawings in my library are Carmine di Napoli's in the "AeroDetail" volume; and Angelo Brioschi's in the excellent "Ali d'Italia" series of monographs. After carefully scaling the larger 1/48 drawings in each, AeroDetail appears to follow "Stormo's" dimensions very closely. But Ali d'Italia shows the 202's core being a bit longer, at about 5280 mm. I've read that Mr. Brioschi's research turned up new info in this area?

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Back to the issue at hand: the little Hasegawa kit is frequently criticized for the rear fuselage's being too short. If the Stormo/AeroDetail numbers are correct, the kit's core length shortfall is negligible though - just about 0.5 mm. But if Ali d'Italia is correct, it's more like 1.5 mm - over 4 scale inches - which gets to be noticeable even in 1/72.

I believe this "core" structure was the same length on the C.200, as on the C.202 / C.205 by the way. So any evidence for those aircraft would be useful as well.

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Re: Macchi 202, fuselage structure length

Post by Editor » Wed Oct 20, 2021 8:24 pm

The guy who would likely have an answer to this question is Riccardo Trotta ("Rick" on this forum), email or pm me and I'll give you his contact info.
Vince Tassone

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Re: Macchi 202, fuselage structure length

Post by MDriskill » Sat Mar 12, 2022 1:41 pm

This will hopefully answer my own question above!

First a shout-out to the "STORMO!" web site! Vince Tassone kindly put me in touch with a friend who owns some original factory drawings. While not available for publication, the owner has graciously allowed me to share related information from them.

The 202's fuselage was built around an internal core structure, consisting of 19 individual frames, numbered "0" (the firewall) to "18" (tail wheel and tail cone attachment). The main fuselage skinning run the full length of this core, with no intermediate vertical joints.

Image

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Establishing the relationship of the panel ends to the frames, i.e. the vertical panel line locations at each end, thus seems critical to correctly scaling the fuselage. Length dimensions of the other major fuselage sections seem reliably established, but not this main structural length.

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The factory drawings provide center-to-center frame spacing, and many other useful detail dimensions, including thicknesses of critical structural frames. After studying photos of the front and rear frames - both of which are complex, with smaller structural members and fastener attachment flanges attached, and various panel overlaps evident - it appears to me the panel lines align with the faces of the frames. Dimensional notes:

+ Adding up the individual frame spacing shows the distance between the centerlines of frames #0 and #18, is 5175 mm.

+ FRONT: Frame #0 is 78mm thick. A panel flush with its front face thus extends 39 mm forward of the frame centerline.

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+ REAR: Frame #18 is 51 mm thick. Its rear face, rounding up slightly, thus extends 26 mm rearward of the frame centerline.

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+ TOTAL LENGTH: The space between the two critical panel lines is thus: 5175 + 39 + 26 mm = 5240 mm. This translates to 163.8 mm in 1/32 scale; 109.2 mm in 1/48 scale; and 72.8 mm in 1/72 scale.

ADDITIONAL NOTES:
+ The drawings show an additional dimension of 35 mm aft of frame #18's centerline. This may indicate the jog in skinning at the rear of the fin, an interesting detail that published drawings and kits mostly miss (front of aircraft to the right in the photo).

Image


+ The factory drawings similarly show a dimension 52 mm forward of the centerline of frame #0. I am not sure what this represents, but my interpretation of photographs indicates it's not related to the fuselage panel lengths.
+ The forward fuselage panel line appears to align precisely with panel joints across the wing root fillet, and top surface of the wing.

Thanks to anyone who has actually read this far! These notes are of course strictly my interpretation of the information that I have on hand. Questions, comments, and corrections are absolutely welcome.

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Re: Macchi 202, fuselage structure length

Post by Editor » Sat Mar 12, 2022 3:25 pm

Very interesting work, so to sum up, the length of the main structural core assembly from the firewall to the rudder post is:

1) Stormo/Drawing/AeroDetail: 5201 mm
2) Ali D'Italia (Brioschi drawings): 5280 mm
3) Mike Driskill's work: 5240 mm

Making the Hasegawa 1/72 C.202 fairly accurate wrt to your work.

We should turn this post into an article so we don't lose it. I'm pretty sure modelers would appreciate knowing how accurate a kit is and the amount of work that goes into verifying the dimensions.
Vince Tassone

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Re: Macchi 202, fuselage structure length

Post by MDriskill » Sun Mar 13, 2022 12:12 pm

Thanks Vince!

I appreciate your help on this one. A couple of notes:

+ The 5280 mm dimension in my first post was obtained by simply scaling up my measurement of Ali d'Italia's 1/48 drawings. I assume they are printed pretty accurately, but I don't know what actual dimension Mr. Brioschi was working with.

+ I would certainly welcome any further input on this question! The structural details at both ends of the main structural frame are quite complex, so it's entirely possible I've missed some subtleties. In particular, I wondered if the skinning might extend slightly past the faces of the structural frame, but again found no "smoking gun" in the pics on hand.

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Re: Macchi 202, fuselage structure length

Post by Editor » Mon Mar 14, 2022 7:40 pm

I think you're way ahead on the curve on this one. When you're satisfied with the information you've gathered we should put together a short article to archive this work and I'm pretty sure modelers would appreciate the effort you put into this. Did you check the dimensions to the Italeri kit?
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Re: Macchi 202, fuselage structure length

Post by MDriskill » Thu Mar 17, 2022 7:53 am

Though the parts engineering of the Italeri 1/72 C.202 kit is a little different, and it has better interior detail, its exterior precisely duplicates the Hasegawa kit, down to the finest of details. If 5240 mm is indeed the correct spacing between these panel lines, both kits are about 1.2 mm short in this dimension, or roughly 3.5 scale inches.

The Hasegawa 1/48 kit gets a little closer. I measure it at 1.0 mm short, or about 2.0 scale inches.

My next crusade is to un-tangle the wonky geometry around the canopy that seems to plague all Macchi C.200/202/205 kits and published drawings...!

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Re: Macchi 202, fuselage structure length

Post by MDriskill » Sun Mar 27, 2022 2:42 pm

Ability to edit posts here is time-limited, but for what it's worth I posted a slightly more refined version of my main post at Britmodeller:

https://www.britmodeller.com/forums/ind ... imensions/

I added some notes to a couple photos and tweaked a couple other things.

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