A Knob motor is one that looks cool and that's about it. Beyond its attractive flame the motor doesn't perform well or really do anything worthwhile. Examples in order of Knoblousness, determined by me, if you disagree with this list I dont care
KnobPro is a word I just made up. Its formal definition is: A motor which on the surface apears to be knob, however, on further investigation actually has redeemable performance qualities.
The list:
1. Skidmark:
Lots of sparks, worst impulse ever. These motors are sometimes mistaken for fireworks because that's what they are, and they share identical ISPs with they twin brother: the fountain. People drool over these motors despite the fact that they do nothing except spit unburned chunks of metal out the butt end, make noise, and probably their most well known attribute: setting fields on fire. Their impulse is awful due to a really bad O:F ratio and the fact that solid is leaving the motor unburned. If you can't get enough of these motors, you are obviously a knob (and a tool, but that's okay), even flying one makes you a knob, we all have a little in us.
2. Smokey:
Skidmark without the sparks, only marginally better impulse, at least you arent spitting out burning hunks of propellant out the butt end, but at the same time your O:F ratio is still Awful. While these wont set the field on fire they will make everything filthy and flying a rocket on a rail after one of these motors is often a terrible experience.
3. Red:
This was a toss up between red and green, but using AMW's site as a reference I needed to put red first because green has a way better ISP. Due to huge amounts of Sr these motors have mediocre impulse and a cool flame. Check and check, both knob attributes. While a red flame isnt as knob as green, the impulse is worse so green has the one up on this one. Red does have some redeemable qualities, mainly that it has a small exponent so the propellant can be used in hairy motors that other propellants would blow up in.
3a Fuscia
This is a tie with red. Why you ask? Well I thought at first it would be less knob than red because its faster, and therefore more bada$$. Then I realized that.....THE FLAME IS PINK. Pink flame are you serious? Not only are you a knob, you are a fairy.
Yes I have flown a Fuscia motor before.
Yes it was an M even.
Purple
I have not yet seen a good purple motor so I am just throwing this in here so everyone knows I didnt forget it. It would probably go somewhere before red. Its definitely knob.
4 White
White is definitely knob, mainly because people fly it just because it looks like SRBs. The difference? Large amounts of zinc and mag just make it look like that and in the end the impulse is bad. If it had lots of Alumium like a real SRB maybe its impulse wouldn't be god awful. I have seen people fly more white motors than anything else just because they look cool. Note, again using AMW's website as a reference, you will see that White has a worse impulse than red, but due to the fact that it doesnt have a wonkey colored flame I decided to put it this far on the list. I guess the fact that it looks real makes it less knob.
KnobPro:
Green
Green gets good impulse. Not only that its fast. Not only that it has applications in the military, yes I have seen rocket motors with green flames in commercial applications. The only knob factor of green is that it has a green flame. This is weird, unnatural almost. So you want to mix a green motor but don't want to be a tool? Its okay, the fact that you are playing with Barium, a highly toxic and potentially deadly chemical makes up for the fact that your motor has a green flame. So, the knobnicity is outweighted by the badass toxic chemicals, and also outweighed by the fact that making a good green motor is simply not easy. The chemicals must be in the perfect ratio and must be prepared correctly in order for the flame to be green. So green motors are peforming, legitamate, toxic, and take mad skilz. The only reason knob is associated with green is because people have alwways associated the two.
LAME Propellant
Aluminum
Boring flame, pretty good performance, and the smoke and flame are almost indistinguishable. 6% (or other close variations) are the lamest motors people can possibly fly. The somewhat better performance does not outweigh the fact that these motors are about as exciting as a retirement home. These are blue motors made by people that dont have the cajones to add CuO.
Cool Propellant:
Fast
These propellants have cool flames AND people that use them have huge cajones. Often times these motors will tear rockets apart which is extra awesome. Not only are these motors hard to make they don't have the uneeded extras of other (knob) motors. Cranking motors are cool. The faster the better. (Kosdon motors are an example, and Supertiger is a mediocre fast motor.)
Awesome propellant
Blue
Blue is the greatest propellant type of all. It is a gift from the Gods and its incredibility can not be described. Blue is high performing and has an awesome flame. Blue can be fast or slow, smokey or smokeless. I have seen blue motors with higher ISP than any other propellant (in the EX community) and have seen more rockets shred at the hands of blue propellant than any other type. While it is hard to incorporate into some cases, in others it is easy. A good blue motor will automatically make your rocket look 100% better than it did before. The flame color is awesome and that speaks to the knob in me, while the performance is there for the practicality. Blue is amazing.