Mine did, too, and since they are so light (25% infill which is only slightly less strong than the much heavier 50% infill) they have no problem with hard surfaces and spin nicely on the way down. I couldn't compare the type 2 and 3 KFms because, incredibly, I had a blowout CATO on a 13mm motor! Blew the top right off of the spinner! Only an empty motor case remained.

That's definitely a first for me, but something always seems to screw up my experiments due to Estes motor issues. A base drag experiment vehicle with 3D printed, changeable base discs nosed in on its first launch when an Estes motor ejection charge did not fire AT ALL. Destroyed the vehicle and an altimeter. A club member on the same day as my recent 13mm issue was burning D12s in spools and doing static tests because he's also had ejection charge problems - one not firing AT ALL. After my base drag vehicle's destruction, I did static tests of many different lots I have and only ONE motor had what I'd call a properly energetic ejection charge. I've also seen ejection charge issues at mass STEM launches. When I was a kid and fired a bazillion Estes and Centuri motors, I don't recall any ejection charge issues.

Anyway, because the KFm2 version that didn't have a CATO spun so rapidly during descent, for safety reasons I've printed new versions with a protective ring. I've printed the original diameter with three blades rather than four to decrease the unnecessarily high (and extremely draggy) spin rate on ascent and two smaller sizes, each in KFm 2 and 3 versions. Whichever one has the most interesting flight characteristics will be the one I'll stick with.

Largest and smallest diameters shown.

Attached Thumbnails

   

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The other day I sat next to a woman who has a profound fear of flying. I wanted to comfort her, so I said, "Don't worry, we're not gonna' crash. Statistically, we got a better chance of being bitten by a shark." Then I showed her the scar on my elbow from a shark attack. I said, "I got this when my plane went down off of Florida." - Dennis Regan