Yes to all of the above. These do NOT work in an engine to add power. BIG CON JOB! But I DO have an application where a squirrel-cage fan motor DOES work effectively as a "blower". I use it on my air compressor in my garage.
Here's the deal. I have a Craftsman "350" 110 Volt compressor, rated at 6.1 cfm (cubic feet per minute) at 90 psi. Except that is its "peak" output, relating to when the tank is emptying faster than the compressor is filling it. So not exactly great when I fire up the big in-line body or dual action sanders, which requires a full 6 cfm at 90 psi, and would suck the tank down to 40 psi in about 5 minutes. At which point the compressor would keep up, but the sander would just plain "suck".
OK, I am a highly trained gas compression engineer (not really, but don't tell the boss or the shareholders!) and I do stuff like this for a living. When I want to get more gas through a compressor, I install a booster compressor to pump up the inlet pressure (which also sucks harder on the gas wells, so they put out more gas). Higher inlet pressure means more cylinder fillage means more output. This works with 200 HP boosters feeding 1400 HP compressors, so why not do the same on my little 3 HP air compressor? So I installed a central vacuum power unit (really just a 15 amp Lamb squirrel-cage blower) to pump air into the inlet, and it increased the inlet pressure to 5 psig (psi gauge, as in more than atmospheric). The simple math says that the inlet is nominally at 14.7 psig (atmospheric pressure at sea level), but more like 13.5 psig at 3200 feet here in Calgary, so to increase it by 5 psi means the compressor now puts out (13.5+5/13.5)=1.37 or about 40 % more than it did "naturally aspirated". It now keeps up to either sander, and even my sandblasting cabinet. It also takes another 8 amps (what the fan uses at full "slip"), on top of the 13 amps that the compressor already uses. Squirrel-cage fans are terribly inefficient, but heck, electricity is cheap (compared to the proper 5 HP twin cylinder compressor that I REALLY need). Hey, they don't call me "Tim the tool man" for nothing...
Here are a couple of not-very-good photos...