Cierva-Nemeth VSTOL, 1/35 scale

[frank2056]

The Nemeth Parasol was an unusual circular wing plane from the mid 1930s that flew fairly well:

https://www.youtube.com/watch?v=fIFyBU83kME

The mid 30s also produced the Cierva C.30 autogiro. The autogiro/autogyros of the day flew well, but they suffered from poorly understood (at the time) edge case issues when landing that could cause a crash. Like an autogyro, the Nemeth had a very short takeoff length (see the video) and an even shorter landing distance. It was also reportedly "stall proof" and very easy to fly.

What if the Cierva corporation had decided to expand their lineup to include an airplane with performance similar to an autogyro (or autogiro) but with the mechanical simplicity of a fixed wing aircraft?

I built a what-if Parasol Kaydet for the Brian da Basher/Brian Perri Memorial GB over at BtS and building it had major challenges. I clearly forgot the issues with that model, because I decided to combine a Miniart 1/35 Cierva C.30a with 3D printed parasol wing!

The base kit is the Miniart Cierva C.30 w/ Winter Ski mainly because it was (strangely) cheaper than some of the other boxings of the same kit. It has nice looking artwork:



I whipped up the parasol wing in Rhino 3D and printed it on my filament printer. The wing was printed in ABS at a fairly low resolution. It would have looked far better in resin, but I wanted to use ABS for this project and could get results (albeit in crappy resolution) in under 5 hours. Here are the upper and lower wing halves:



They look hideous, especially the lower wing (which is almost flat). I may skip the lower half and just glue on a sheet of styrene.

After much sanding, some acetone smoothing and a layer of primer, the upper wing is coming along. I left the supports in place, since they give the print some rigidity:



I also started on the kit. Miniart did a fantastic job with the C.30 - it's very detailed; the engine and cockpit could be models on their own. Here's the engine and cockpit:



The engine is pretty much finished. I added some ignition wires and a control line that's visible on the real plane:



The kit comes with a fairly extensive PE sheet, which included 28 small (1mm or less) diameter connectors for the exhaust ports on the cylinders. I used 14 and skipped the rest. As you can see, (or not) they're not really visible.

Since this will be a fixed wing aircraft, I added two control sticks to the cockpit:





I now have to figure out how to attach the wing (which is heavier than it looks). I may leave one of the rotor pitch controls since it'll add another point of support. In the world of this design, the wing would have a variable angle of attack for takeoffs, which would provide an even shorter takeoff distance.
I'll also have to add a rudder. The Cierva has a vestigial rudder that looks more like a trim tab. I'll add a bigger surface in its place, to give this version some yaw control.

[PR19_Kit]

Fascinating, and an outstanding looking model so far. 

The Nemeth Parasol has a veritable  plethora of control surfaces. There's a HUGE flap in the centre of the wing TE, plus ailerons, elevators and rudders etc as normal.

But they didn't use the flap to land, it stayed retracted all the time, so what was it for? 

[Wardukw]

Funny as hell Frank as yesterday i watched a vid on YouTube on that exact plane..ed nash military matters i believe is his channel name..a very cool idea and a very easy plane to fly and land and bow your building it 
Oh its a strange world sometimes 
This is going to be a very cool build mate 

[NARSES2]

Fascinating, and an outstanding looking model so far. 

Couldn't of put it better 

[frank2056]

Thanks guys. The MiniArt kit is a detailed, involved build but it's so well engineered and thought out that it's actually been enjoyable to build, so far.

The Nemeth Parasol has a veritable  plethora of control surfaces. There's a HUGE flap in the centre of the wing TE, plus ailerons, elevators and rudders etc as normal.

But they didn't use the flap to land, it stayed retracted all the time, so what was it for? 

The plane could land almost vertically, using the wing as a "parachute". I assume that the pilot dropped the flap to slow the plane down and control the flow of air out of the "parachute".

There seems to have been a modified version with the ailerons and flap slightly below the wing; I don't know if it was an improvement.

[Rheged]

Fascinating, and an outstanding looking model so far. 

Couldn't of put it better 

I agree!!

[Wardukw]

Frank from what i saw on the vid the pilot could land this thing in like 20yrds and take off in 60yrds ..the stall speed was extremely low and the plane handled very well.
There was a issue with something but i dont remember and i dont think it was much at all.

[PR19_Kit]

I assume that the pilot dropped the flap to slow the plane down and control the flow of air out of the "parachute".

Except he didn't.

In the vid the flap stays solidly up all the time during the approach and the touchdown. It does look an amazingly soft landing though, so I guess there's a hefty ground effect involved too.

[frank2056]

The video seems to show only a "vanilla" flight. This June 1934 issue of Popular Mechanics says Nemeth stalled the airplane in mid flight and landed it like a parachute. I assume he used the giant flap, but other reports say he only turned the engine off. I haven't found any pictures of it fully deployed.

[Wardukw]

Seems he could land the thing anywhere as it pretty much lands like a chopper with a extremely slow stall speed ..its got me thinking of building a rc verison as a test bed and if i can scale it to thr fusealge i want to use then it should behave like the real thing...i hope 

[frank2056]

Here's a flying scale version (but no videos of it in flight)

[Wardukw]

Nice one Frank 
His scale of 1.8 shows how small thr real thing was..a wing or disc span of 760mm is small man ...my smallest rc plane has a bigger span and thats after crashing it 

[Tophe]

Good model project! and start 
Have you seen that I transformed the Nemeth Parasol into a twin-boomer at https://www.whatifmodellers.com/index.php?topic=20326.5940 ? (3rd entry of the page)

[frank2056]

Phill, the flyable model still sounds pretty big to me at 760mm long!

Tophe - that version should be called a half moon twin boomer!


I've made progress on the model - the kit  part is almost finished; I was surprised at how quickly I got to this stage, despite the seemingly fiddly parts and the PE. I despaired a bit over the "poor" fit of the tail, but the real Cierva looks like this, gaps and all. I moved the compass up to the instrument panel in the rear cockpit as well:



The rotor head (or in this case, wing support) is just tacked in place. I drilled holes for small brass pins, but I may not need them:



Now it's on to finishing the wing, ailerons and flap, plus deciding on wheels or skis and the final colors.

[Tophe]

Great work on the model, congratulations!

Tophe - that version should be called a half moon twin boomer!

Good word, thanks!