General Information
We love hearing from our customers, and we're always here to help! However, we often find that many questions can be answered simply by taking a moment to read the instructions. By carefully reviewing them, you can quickly find the essential information needed to assemble and fly your ProXX rocket motor with confidence.
Yes, you can download .pdf files in the hardware section of our products page.
We receive frequent requests for beta testing of new products. While we appreciate the interest, once a new motor product has been tested at the factory and certified, we have a good understanding of its performance in your rocket. Therefore, we do not offer beta testing programs. New products are released to market once they are certified and available to dealers, and press releases are shared on major newsgroups and forums to keep you updated on new developments.
We provide detailed motor data and thrust curve information on the Pro-X website under the product listings. This information can help you select the motor that best fits your needs. If you require additional assistance, feel free to contact us at the Pro-X support email prox_support@cesaroni.net
While our assembly instructions are designed to be thorough, we understand that you may need additional assistance. If you’d like to speak with someone directly, you can call us at 905-887-2370 between 9:00 AM and 4:30 PM EST, Monday through Friday. Our team is here to help.
Performance & Safety
A minimum acceleration of 5 gees is recommended off the pad to ensure sufficient flight speed for aerodynamic stability. This calculation must include the rocket's weight in a ready-to-launch condition, which means everything installed, including the motor.
Generally, you can use the average thrust from the manufacturer's data or industry certification data to calculate your thrust-to-weight ratio. However, consider examining the thrust-time profile of the motor during the initial burn, especially for motors like the Pro98™ line of moonburners, which deliver maximum thrust at ignition and decline steadily over time.
For example, the M520 has an average thrust of about 520 Newtons (117 pounds). While it might seem that this motor can only safely lift a rocket with a gross takeoff weight (GTOW) of 23-24 pounds based on the average thrust, its initial thrust is around 300 pounds, allowing it to safely fly rockets with a higher liftoff weight.
In some cases, you may need to provide data to the Range Safety Officer (RSO) if your thrust-to-weight ratio is marginal due to a regressive thrust profile. When in doubt, maintain an average thrust-to-weight ratio of 5:1 or better.
Delay Adjustment
Delay is defined as the time from motor burnout to ejection charge firing, not from ignition. Pro29™, Pro38™, and Pro54™ rocket motors have an adjustable delay setting. Each motor is equipped with a delay element that provides the delay time indicated in the motor designation.
For example, the 765J330-16A has a 16-second delay as supplied. The ProDAT™ (ProXX Delay Adjustment Tool) is used to reduce this delay. The Pro38™ ProDAT™ tool offers four fixed delay reduction settings, allowing you to choose from five total delay times. The Pro54™ ProDAT™ tool features a vernier adjustment for precise delay time reduction from zero to 10 seconds.
Note: It’s important to remember that the setting on the delay tool indicates the amount you are removing from the delay, not the final delay time itself.
Ejection Change
The ejection charge is retained by a thin plastic cap held in place by adhesive. Use a small screwdriver to pry out the cap, then tap out the ejection charge, which can be used in your deployment system.
Pro38 motors contain 1.3 grams of FFFFG black powder, while Pro54 motors contain 2 grams. You may choose to plug the hole afterward, but it's not necessary unless you’ve adjusted the delay setting.
Why is there a gap between the thrust ring and the motor case on Pro38 motors?
This gap is normal due to production variation in the length of the propellant grains. The reload is designed to seat fully in the case with a gap of about .030" between the thrust ring and the casing. If the grains are slightly short, the gap will be less, and if they are longer, it will be more. Simply screw the reload into the case until snug but not overtight.
Thrust Ring Gap
This is normal. In production, there is some variation in the length of the propellant grains, therefore the total length of the propellant grain stack varies. The reload is designed to seat fully in the case with a gap of about .030" between the thrust ring and the casing, if the grains are exactly the design length. If the grains are a few thousandths of an inch short, then the gap will be less. If they are a little longer, the gap will be more. Simply screw the reload into the case until it is snug but not overtight. If the gap is excessive (see instructions), disassemble the motor and check over the reload assembly. Reassemble.
Ignitor Compatibility
Theoretically, yes, but it's not recommended. The ignition system on Pro38 and Pro54 motors is designed to work reliably. Commercial electric matches are proven to provide sufficient output to ignite the igniter pellet contained in the motor core.
In past tests, we found that using a homemade pyrogen-dipped igniter can lead to catastrophic failures, such as igniting the motor without thrust. Stick with the recommended stock igniter for the best results.
CTI supplies Oxral electric matches with all Pro38™ and Pro54™ reloads, except for G class reloads, which come with a Daveyfire mini electric match due to the small nozzle throat.
The shroud enhances ignition reliability by directing the match's output towards the ignition pellet. For optimal performance, the shroud can be slid down and secured using a piece of the red plastic tube that shorts the leads together, effectively directing the match output forward.
Should I support the igniter if using Pro38 or Pro54 motors in an upper stage?
For most Pro38 motors, additional support is likely unnecessary due to the small core preventing the match from collapsing under typical acceleration. However, if using high-thrust booster motors or larger Pro54s, you may tape the igniter to a thin wooden dowel for added support. Ensure that the assembly does not restrict nozzle flow.
All Pro75™ and Pro98™ reloads come with an igniter support dowel or tube, which should be used at all times.
Ignitor Support
It is usually not necessary to support the igniter in Pro38 motors unless using a very high thrust booster, as the small core prevents the match from collapsing under typical acceleration. Many successful multistage flights have been made without additional support. However, if you choose to provide mechanical support, ensure it's minimal.
For "I" class (3G) Pro38 motors and larger, as well as any Pro54 motors, you can tape the igniter to a thin wooden dowel or bamboo skewer (no larger than 1/8" in diameter). Trim the dowel to the appropriate length so that the plastic nozzle cap can fit to retain the assembly.
Be cautious that your support does not create excessive nozzle restriction, as this could lead to issues during the igniter's ejection due to sudden depressurization. Proper venting is important; blocking igniter gases is not advisable.
All Pro75 and Pro98 reloads come with an igniter support dowel or tube, which should be used at all times. Tape this support alongside the electric match leads, ensuring the end rests against the bottom of the Oxral match shroud for added stability.
Motor Classification
The standard 1 grain G, the G69, meets the US definition of a model rocket motor, containing 62.5 grams of propellant. However, the Smoky Sam 1 grain G, the G79SS, contains about 80 grams of propellant, classifying it as a high power rocket motor in the US. In Canada, both motors can be classified as model rocket motors based on different criteria.
The Pro38™ G motors were not designed to compete on cost with smaller G motors. As the smallest motors in their diameter, they have relatively higher costs due to fixed component costs like nozzles and closures, which do not scale down proportionately with smaller motor sizes.
These motors were created to provide options for low-altitude tests and as upper-stage motors, allowing smaller 38mm models to fly as model rockets without needing motor mount adapters.
Cross-Brand Compatibility
Pro75™ and Pro98™ reload kits fit both CTI and RMS™ systems, with differences only in the type and number of o-rings used. All ProX™ cross-brand compatible reloads are supplied with the necessary o-rings.
The development of cross-brand compatible reloads was initially driven by customer demand for high thrust M class 98mm reloads that fit existing RMS hardware, leading to the creation of a line of reloads for the sport rocket market.
Cross-brand compatible reloads are a recent innovation in high-power and mid-power rocketry. Initially, the existing rules and regulations from rocketry associations did not adequately address their introduction. After discussions among the motor testing committees of these associations, it was determined that all cross-brand compatible reloads must complete a comprehensive certification firing series in any hardware they are intended for use with.
As of now, the following reloads are certified for use in both CTI ProX™ hardware and RMS™ hardware:
Pro75™ Reloads:Classic™ Propellant Reloads: K510-P, L800-P, L1115-P, M1400-P
White Thunder™ Propellant Reloads: K1085-P, L1720-P, L2375-P
Red Lightning™ Propellant Reloads: M1810-P
Blue Streak™ Propellant Reloads: M1670-P
Skidmark™ Propellant Reloads: M1770-P
Pro98™ Reloads:
Classic™ Propellant Reloads: L600-P, M1060-P, M1495-P, N2500-P
White Thunder™ Propellant Reloads: M2505-P
Red Lightning™ Propellant Reloads: M1890-P
Vmax™ Propellant Reloads: L3150-P
Classic™ Propellant Moonburners: M520-P, M795-P, N1100-P
Skidmark™ Propellant Reloads: 8088M1790-P
Pro75™ Reloads:
Currently no RMS™ reloads are certified for use in CTI ProX™ hardware. It is up to the reload manufacturer to supply reloads and hardware to the motor testing committees for certification firing. If Aerotech chooses to have their reloads certified for use in ProX™ hardware, that's fine but it's up to them to do so - you'll have to contact them with any questions on that subject. Functionally, however, the answer is yes. Compatibility works both ways. We have compatible hardware in all equivalent 75mm sizes and 98mm sizes from 98/5120 up to 98/15360 case size. Several RMS™ reloads have already been flown in ProX™ hardware at Canadian launches. The only thing extra that is needed is a set of the correct o-rings for the ProX™ hardware.
Pro75-2G = RMS75/2560
Pro75-3G = RMS75/3840
Pro75-4G = RMS75/5120
Pro75-5G = RMS75/6400
Pro75-6G = RMS75/7680
Pro98-1G = RMS98/2560
Pro98-2G = RMS98/5120
Pro98-3G = RMS98/7680
Pro98-4G = RMS98/10240
Pro98-6G = RMS98/15360
Pro75-3G = RMS75/3840
Pro75-4G = RMS75/5120
Pro75-5G = RMS75/6400
Pro75-6G = RMS75/7680
Pro98-1G = RMS98/2560
Pro98-2G = RMS98/5120
Pro98-3G = RMS98/7680
Pro98-4G = RMS98/10240
Pro98-6G = RMS98/15360
Warranty and Support
In the event of a warranty claim where a ProX™ grain is used in a compatible motor case, we replace (on a case by case basis) the hardware with our ProX™ brand hardware, not a monetary refund or a case from the original manufacturer. The ProX™ line now has a large selection of Pro75 reloads, and a replacement case from ProX™ will not limit the flyer in terms of available colors and/or effects in any way. Further, ProX™ hardware will support an even wider variety of options in the (near) future.
CTI warranties its products against defects in manufacturing for a period of one year. If you have a problem with a ProX™ motor product, contact your dealer for support. Dealers usually provide replacement product from their inventory, which are then replaced by CTI to the dealer. However, if this is not possible, we will arrange for replacements to be sent to your dealer. CTI can not ship reload products directly to the customer. If you should ever have a defective reload, we will want to know all the details you can provide about the incident - manufacturing dates on the reload package, weather conditions, a description of the failure, etc. This helps us determine the cause and apply corrective measures.
You can purchase ProX™ motor hardware, reload kits, and accessories from any of the dealers listed in our dealers section. There are dealers throughout the continental US, in Canada, and a growing network of dealers in Europe. CTI does not sell motor products directly to consumers.