Hello,
I like finding ways to use data to help support my decision making. When it comes to picking a motor, there are a myriad of options and many different types of criteria that may be used to select one. Putting aside propellant types, thrust curves, and other considerations, I was curious about how the different motor systems compared in simple terms of $$ per Ns. So I collected some prices from Sirius Rocketry and Wildman, picked a range of motors that I was interested in (mostly LPR to MPR), calculated the $$ per total impulse, and plotted that metric vs total impulse.
No surprise that the cost per total impulse goes down as motor sizes go up, but there are a few things I found interesting in here.
A couple of bullet points:
C & D range: Estes black powder
E range: Aerotech 24/40 (also gets you baby Fs)
F range: Aerotech Economax
G range: Aerotech 29/40-120
H range: Aerotech 29/240
For H, I, and beyond, I'd lean towards Cessaroni because the motor loading and cleaning is easier, the cases are cheaper, and the cost is about the same.
Obviously there are many more criteria that go into choosing a motor, but this is one that can be plotted for direct comparison.
Link to original in case it gets downsized
I like finding ways to use data to help support my decision making. When it comes to picking a motor, there are a myriad of options and many different types of criteria that may be used to select one. Putting aside propellant types, thrust curves, and other considerations, I was curious about how the different motor systems compared in simple terms of $$ per Ns. So I collected some prices from Sirius Rocketry and Wildman, picked a range of motors that I was interested in (mostly LPR to MPR), calculated the $$ per total impulse, and plotted that metric vs total impulse.
No surprise that the cost per total impulse goes down as motor sizes go up, but there are a few things I found interesting in here.
A couple of bullet points:
- In size 38mm, Cessaroni and Aerotech reloads cost about the same. (ignoring the 3 Aerotech 38mm motors that ship HAZMAT free).
- The Aerotech 24/60 reloads are more expensive per flight and per impulse than the 24/40 reloads. I don't see any good reason to use the 24/60 case unless you just really need a few more Ns in a 24mm case.
- The Economax motors are a better deal than the 29/40-120 reloads. The F67 ships HAZMAT free, but the larger G67 is HAZMAT, so the main advantage of the 29/40-120 reloads is HAZMAT free (and variety).
- In the smaller range of the 29/40-120, you're better off with 24mm single use motors (E15, E20, E30).
- The Aerotech 24/40 reloads are a good bargain.
- If you're looking for "D" size reloads, it is more economical to adapt down to the 18/20 case, than use the 24/40 reloads.
C & D range: Estes black powder
E range: Aerotech 24/40 (also gets you baby Fs)
F range: Aerotech Economax
G range: Aerotech 29/40-120
H range: Aerotech 29/240
For H, I, and beyond, I'd lean towards Cessaroni because the motor loading and cleaning is easier, the cases are cheaper, and the cost is about the same.
Obviously there are many more criteria that go into choosing a motor, but this is one that can be plotted for direct comparison.
Link to original in case it gets downsized