I was perusing the Zlin Aviation website and came across their "Shock Cub". Of course the first port of call, after the photos, was the performance spec's - or should I say performance claims?

The takeoff distances I can believe pretty easily, much heavier aircraft can accomplish those distances. It was the landing distances which interested me...

REQUIRED TAKE OFF SPACE (SINGLE PILOT) < 35 mt ( 115 ft)
REQUIRED TAKE OFF SPACE (MTOW) 57 mt (188 ft)
REQUIRED LANDING SPACE (SINGLE PILOT) < 18 mt (58 ft)
REQUIRED LANDING SPACE (MTOW) < 35 mt (115 ft)

Then I saw the stall speeds...

STALL SPEED WITH FULL FLAPS (MTOW) 23 mph (20 kts)
STALL SPEED WITH FULL FLAPS (SINGLE PILOT) 18 mph (15 kts)

For comparison, the SuperSTOL (effectively the same plane) tenders a stall speed of 28–32 kts, which is very believable.

My first reaction was to distrust the Zlin numbers. I thought - surely those are indicated airspeeds, which come with a massive error because of the high stall AoA. Or a bit of an overzealous sales pitch perhaps?

So I wanted to ask - can anyone confirm the real-world performance of the Shock Cub?

The only Cub clone I have experience with is one that has slats, 60 degree flaps, and 100 hp. Savanna or Savage or something like that. A guy brought his from KC to learn SMFT stuff. Very impressive. Does anyone record In Ground Effect stall speed? It would be much lower than Out of Ground Effect stall speed. Not being a user of the airspeed indicator, I have no idea what speed any of the airplanes I fly actually stall at in or out of ground effect. Even out of ground effect, the sound and feel and buoyancy and stick position and sloppiness and such are much more accurate than the airspeed indicator.

I was interested in these as well. In Canada you can only buy them as a complete plane in the advanced ultralight category. I was quoted $107000 for a 180 hp Lycoming model. Seems like a good price. Wish I could get it in kit form and build it exactly how I like though...

A1Skinner wrote:I was interested in these as well. In Canada you can only buy them as a complete plane in the advanced ultralight category. I was quoted $107000 for a 180 hp Lycoming model. Seems like a good price. Wish I could get it in kit form and build it exactly how I like though...

It seems like they've only recently come out. I suppose a kit will follow in due course.

Battson wrote:

A1Skinner wrote:I was interested in these as well. In Canada you can only buy them as a complete plane in the advanced ultralight category. I was quoted $107000 for a 180 hp Lycoming model. Seems like a good price. Wish I could get it in kit form and build it exactly how I like though...

It seems like they've only recently come out. I suppose a kit will follow in due course.

I hope that's the case. On their website they show it available as a kit, but both the Canadian and US reps told me they are only available here as complete planes.

contactflying wrote:...I have no idea what speed any of the airplanes I fly actually stall at ...the sound and feel and buoyancy and stick position and sloppiness and such are much more accurate than the airspeed indicator.

On a side note, I think that's a better way to articulate what is often just referred to as 'flying by feel', or similar. Good description, Contact.

These speeds are indicated air speeds? Calibrated air speeds for the high AOA? The Sport Cub I fly has a generous error at the bottom end. It will indicate 28mph while the GPS says 44, on short final. I was really impressed by the 28 thinking I was a real Cub man until I looked closer on the video and saw the ground speed on the GPS.

A company like ZLin, would they take advantage of that error for marketing? Who knows. 20mph CAS is really really slow.

Zzz wrote:These speeds are indicated air speeds? Calibrated air speeds for the high AOA? The Sport Cub I fly has a generous error at the bottom end. It will indicate 28mph while the GPS says 44, on short final. I was really impressed by the 28 thinking I was a real Cub man until I looked closer on the video and saw the ground speed on the GPS.

A company like ZLin, would they take advantage of that error for marketing? Who knows. 20mph CAS is really really slow.

That was my first thought, until I saw this video.... Wow!

It looks like the flags, windsock, and comments from the OP suggest it's only got 5 kts headwind. Even with 10 kts or even 15 kts headwind at altitude, this is impressively slow.


I hate to complain about a cool video, but I didn't much care to see him flying so slowly so close to the ground - but then I thought, clearly he would not be pushing the limit so close to the ground. Nobody would want to stall at 200ft AGL... it's semi-suicidal. So in that case, we can deduce the plane is probably capable of even slower flight.

Very short stopping distance too, given smooth tires on soaking wet grass. I think we can all relate to that, there is literally zero braking.

Wow, Battson. When you show videos like that it really makes my wallet cringe... Ha. I wonder if that's the 180 hp model?

Totally different wing plan form then a Just SS, a much deeper chord for one thing. Looks pretty cool, but this is the same company that reversed engineered (to be kind, they blatantly ripped off the Rans S-7 design, down to the parts being interchangeable) and called it their own. Many changes since then but that still sticks in my craw, and I would keep a very firm grip on my wallet when around a company that would have the frigging nerve to do what they did.

With that caveat out of the way, it looks to land pretty slow, but I wonder how the cruise is ? It bears watching, just remember the companies origin.

courierguy wrote:Totally different wing plan form then a Just SS, a much deeper chord for one thing. Looks pretty cool, but this is the same company that reversed engineered (to be kind, they blatantly ripped off the Rans S-7 design, down to the parts being interchangeable) and called it their own. Many changes since then but that still sticks in my craw, and I would keep a very firm grip on my wallet when around a company that would have the frigging nerve to do what they did.

With that caveat out of the way, it looks to land pretty slow, but I wonder how the cruise is ? It bears watching, just remember the companies origin.

That's crappy to hear Tom. Thanks for letting us know, I never realized they ripped rans off.
As for the cruise speed, I have my 180 to go faster. I want more of a have fun plane...

I can't see how indicated or calibrated airspeed would be accurate at his out of ground effect very high pitch attitude. If he would use apparent rate instead of either, he would not be standing on his tail at a hundred feet and faster (at less pitch attitude) just before touchdown. I don't see the utility of such a high pitch attitude without a chin bubble so that we could land the airplane that slow.

courierguy wrote:Totally different wing plan form then a Just SS, a much deeper chord for one thing. Looks pretty cool, but this is the same company that reversed engineered (to be kind, they blatantly ripped off the Rans S-7 design, down to the parts being interchangeable) and called it their own. Many changes since then but that still sticks in my craw, and I would keep a very firm grip on my wallet when around a company that would have the frigging nerve to do what they did.

You've been reading the SC forum, and listening to Roddy, haven't you?
Everyone has their detractors / critics. I remember what my father used to say "believe nothing that your hear, and only half of what you see"

With that to one side, the facts are they are selling a new and apparently very capable aircraft. Like you, I am keen to know about real-world GPS speeds for Vso and cruise.