Fan Cart technology seems to have regressed...

 In virtually every way, physics teaching equipment now is far superior to physics teaching equipment a decade or two or three ago.  Vernier and Pasco have continued to innovate, making the probes and toys they sell better with every iteration.

Except, for some reason, simple fan carts.  

First, a warning: I bought four of the modern Vernier fan carts (pictured at top) last year.  Only one of them still works.  They hit the floor, through normal use not abuse; and the spokes supporting the fan casing broke, and the fan blade chipped, and now they just make an obnoxious sound but don't work.  Oy.  I do not recommend.

The traditional PASCO fan cart (the second picture) has been a workhorse for me for years.  It doesn't break through normal use, at least not until a half-life of like 10 years.  I like that it charges rather than uses batteries.  I like that the fan can turn 360 degrees.  It is fantastic.  It's old, but great.

What about fan attachments? 

I like the new PASCO fan attachments (third picture), which sit on either a smartcart or a dumbcart. 

These are battery operated.  They have three speeds accessible simply by clicking one button.  It can do so much advanced stuff if you hook it to the smartcart and use sparkvue; but for AP physics 1 or conceptual physics, all I want is a simple fan, so this is great.

The attachments can't rotate, which is fine - that's why I have the traditional fan cart too, rather than just attachments.  

But the *old* PASCO fan attachment came with a bar on which MULTIPLE fans could sit.  I loved doing the demo in which I had two carts pushing left and one pushing right... and asking how the cart could nevertheless move to the right.  With the ability to put three separate attachments on a single cart, we could do a straight-up netF = ma experiment with constant mass, by using different total numbers of batteries (up to 12 total!) in the fans, thus varying the net force, and measuring acceleration with a motion detector.  I also used to put the old fan attachment on top of the visual accelerometer, on top of a dumbcart, and you could still see the lights indicating the direction of acceleration.  

The new attachment works fine, but is incompatible with multiple fans at once, and incompatible with either the old or new visual accelerometer.

I'd love to hear, in the comments, your experience with newer fan carts.  Is there a product out there I'm missing?