Bell H13CX Coaxial Helicopter

[frank2056]

I have a couple of the old Revell 1/35 scale H-13 Sioux helicopters in the MASH boxing. They were cheap and fairly nice, although the tubing detail is out of scale and often warped. One of the kits has the Eduard PE set as well as an article from Fine Scale Modeler on how to scratchbuild the tubular tail out of styrene rod. I'll eventually build that as a regular H-13 or a Bell-47.

The other kit had a hopelessly warped tail; there were twists and turns all along its length, even in the center section where the engine sits. I had this kit rattling around for a few years until I decided to turn it into a coaxial rotor (similar to the Hiller XH-44) version of the H-13. I have a paper model of the XH-44 and used the design to get ideas for this one.

Here is where I am so far:

Top view with the rotors in place. The interior and the rotors are not glued:


Front view:


Side view:


Front view with figure, for scale:


The rotor span may seem small, but it's slightly wider than the XH-44 span, and the blades are slightly wider. The total blade length is also about 40% greater than on the original H-13.

I covered the rear framework with thin styrene sheet, after I cut away the most warped sections. The pointy tail still has a slight twist to the side.
The rotor assembly and blades are all scratchbuilt. The tan "transmission" is a tank part, but everything else is styrene tubing, sheet and small Gundam detailing parts.
Still to do are the rotor linkage and the interior.

The color is Tamiya IJN gray. I tried painting it yellow, but I had coverage problems and went with the Tamiya, which covered well in one coat.

[ysi_maniac]

Nice!

[Jschmus]

Not to nitpick, but shouldn't the rotors be facing in opposite directions?  Otherwise they won't cancel each others torque.

Cool model, though.

[frank2056]

Not to nitpick, but shouldn't the rotors be facing in opposite directions?  Otherwise they won't cancel each others torque.

Cool model, though.

I had the lower rotor flipped upside down in the pictures. The two rotors are independent, so they rotate in opposite directions.

[John Howling Mouse]

All the way 'round cool.

[PR19_Kit]

Neat, the original 'Flying Phonebox'! 

[TsrJoe]

looks sweet, itd be neat to put one of those teeny cheapo rc helicopter gearboxes and motor in it so it rotates whilst sitting on the table 

[Taiidantomcat]

Brilliant! Figure looks good too

[Tophe]

funny look!

[sandiego89]

Great work.  Nice save from the warped kit. 

[RotorheadTX]

Good stuff! Go man, go!

[frank2056]

I have to figure out how to do the linkages, etc. Should I just add some thin lines and a large(er) hub to hide all the details? Or add some representative hinges? I'm not too clear on how coax helicopter rotor heads differ in details from regular helicopter rotor designs. I'm not sure I want to know, or this project will never get finished...

Oh, and I thought I had an original idea. Wrong! While looking up coax rotor designs, I found the Wagner Sky-Trac. Look familiar?

[Taiidantomcat]

Oh, and I thought I had an original idea. Wrong! While looking up coax rotor designs, I found the Wagner Sky-Trac. Look familiar?

I thought you did too! How about that?! good news is the rotor head does look more simple than I expected 

[Doc Yo]

 looks pretty neat so far. I'd say go with the thin lines/larger hub. The rest of the craft is pretty elegant, and
too much plumbing up top would be a bit distracting.

[sotoolslinger]

Extremely neato