Aksrockets: Aerotech vs. CTI

Aerotech vs. Cesaroni (up to 54mm motors)

For those of you who dont know what both of these words means: Aerotech (AT) and Cesaroni (CTI) are the largest manufacturers of mid-power and high-power motors. Both make AP based rocket motors from E to N ( CTI now has a few "O" motors in production). While they both make basically the same product, they both have many differences. One of the big questions people ask when they think about getting a certification is: What company should I go with? It would be best to go with whatever your local motor vendor carries. In my case, Bruce (our motor vendor) carries both Aerotech and CTI reloads. If you motor vendor carries both you have to make a decision based on what best fits your needs so, here is a comparison:

Cases:

Both At and CTI require you to purchase a case to fly reloads. A case is an aluminum tube that the actual reload fits into. Without the case the propellant would just burn out the sides and your rocket wouldnt get off the ground. AT and CTI both have different case systems, AT reloads will not work in CTI cases, and CTI reloads do not work in AT cases.
         A CTI 38 case has a plug at one side and internal threads at the other. The motor is slid into the case and an aft closure is screwn into it. 38mm motors have the Aft closure moulded into the motor, which makes buying cases a bit cheaper.
         Aerotech cases consist of : a case, a forward closure and an aft closure (and sometimes a thrust ring). The case has internal threads on both sides and the closures screw into both ends. The forward closure has a well for the BP to be stored in (unless the motor is plugged). The aft closure has a raised edge that bumps up against the motor tube.
       CTI cases are much cheaper then an AT case. A 38mm 2G case (H motors) will cost about $30 while an Aerotech 38/240 (H motors) will cost about $90. However, once you buy a set of closures, you can use them in any aerotech 38mm case. This makes buying cases easier.
       Cesaroni and Aerotech both now have a reload adapter system. Cesaroni uses spaces so that it is possible to fly a 2 grain motor in a 4 grain case. This gives you lots more options in one case. for example, with a 3 grain (3G) and 2 spacers you can use over 20 different reloads, as opposed to the eight you would be able to use without the spacers. Aerotech recently released it's own spacer system with a floating forward closure. Still, the system is more expensive then CTI's spacers.

An Aerotech 36/360 case (with closures)
Photo from Apogee Components

Motor Assembly

Motor assembly also differs between companies. A CTI reload is about 75% pre-assembled. The grains come in a central liner with the delay and nozzle pre-installed. CTI's delay's are adjustable. To adjust the delay, use the delay drilling tool. The delay half is inserted into the tool and a drill bit drills out the proper amount of delay. You slip the delay back into the liner, then slip the liner back into the case and tighten it. That's it! At motors take quite a bit more time to build. The first time I built an AT reload, it took me 45min. Now it takes me about 10, depending on the motor. AT reloads come with independent propellant grains, which slide into a liner. You need to grease o-rings, install the nozzle and do other things until the motor is assembled. If you might enjoy assembling motors, aerotech might be the way to go. If you just want a quick reload to build you might want to consider CTI.

Reloads

When deciding which manufacturer to chose a big thing to take into account is the cost of the motors. Aerotech's motors are tons cheaper per-flight then cesaroni motors. For example, if I wanted to fly a small I motor, an I161W would cost me about $38 but a Cesaroni I345 would cost me about $43. Luckily, our local motor vendor carries an I161 for $25!

Propellants:

CTI and AT both have different kinds of propellants to choose from. Most are white, red, green, black "sparky" or fast burning. CTI and AT's propellants differ slightly AT's reds are different then CTI's red and CTI's fastburning is different then AT's fastburning. Most people have opinions on which propellant they like more. Here's mine:

The following is just my opinion:

(CTI)White Thunder vs. (AT)White Lightning: I like White Lighting quite a bit more. White Lighting has a longer burn time and more smoke. White Thunder has a quick burn time and not much smoke. Both Propellants are widely available.

White thunder (an I345)


White Lighting (an I161)

Blue Thunder (AT) vs. Blue streak (CTI): Both are blue Propellants. The blue thunder has very little smoke and very little flame but buns very fast. CTI's Blue Streak has different characteristics. Blue Streaks have much more flame then a Blue Thunder. Just look at the pictures below:

An Aerotech F52-8 Blue Thunder

A CTI F36 Blue streak

Redline (AT) vs Red Lighting (CTI): I love a good Redline. In my experience, Redlines have more flame then Red Lightings. Some Red Lightings are cool too. I love the G54R with a 3 second burn.

Red Lighting

Redline

Warp-9 vs V-max: Warp 9 and Vmax are both fast-burning propellants. Aerotech's Warp 9 is the fastest burning propellant available, with a G motor burning in .4 seconds. CTI's Propellant is a bit slower, burning in .7 seconds. Both these propellants are used for both mach-breaking fast flights or heavy rockets that need a little extra "oomph". Even though the Warp-9 burns faster, I like the Vmaxs more here is the reason: Warp-9 motors are always plugged so the require the use of an altimeter to fire of the ejection charges. V-Max motors use a conventional delay. Also, Aerotech Warp-9s cost about 1/3 more then regular motor, V-Maxs cost the same.

A H999 warp-9

A H400 V-max

Mojave Green(AT) vs. Green (CTI) CTI currently has very few green motors. They only have 2 Green motors in the 38mm engines. Mojave green is widely available.

A CTI green


An Aerotech Mojave Green.

Black jack (AT) vs. Smokey Sam (CTI). Both of these motors are black motors. Instead of a flame they have thick, black smoke. Aerotech's BlackJack is a slow burning propellant with a long burn time. CTI's Smokey Sam is a quick burning propellant.

An F22J

An H178DM
Photo by Jeff M.

Other Propellants:

Both AT and CTI have propellants that cannot be cross-compared. Here they are:

Metalstorm: Metalstorm is a "sparky propellant" which means that Sparks are thrown of the motor along with the flame, personally "sparkies" are my favorite to watch. Metalstorm combines a White flame, white smoke and a shower of sparks. AT currently has the only "white sparky" Propellant.


My Mach mobile on a G75M

Skidmark vs Dark Matter: Aerotech and CTI now both have a black "sparky propellant". Both have black smoke, bright yellow sparks and a loud roar. Ive flown both types and both have their ups and downs. Both motors will be less powerful then the other motors in the same case. You wont use these motors for preformance, just show. In my experience, aerotech's DM has more sparks, more smoke, and more roar then the CTI equivalent, but a lower ISP. Since DM has not been around that long, There are only a handfull of reloads available, while skidmarks are available in almost every case size.

An H178DM


An I180 Skidmark

Imax: Imax is a strange propellant, It starts off burning green and turns black before burnout. Imax also has a higher propellant density then other motors, making it common for altitude record attempts.