AeroTech RMS Motor Hardware Sets: 29mm vs 38mm vs 54mm

Quick answer

If you are buying your first high power AeroTech RMS hardware set, start with the 38mm size. The RMS-38/1080 set includes a complete case, forward and aft closures, and a forward seal disc, so it is ready for any RMS-38/1080 reload. Choose 29mm only if you are staying with smaller high power reloads, and choose 54mm only if you already fly larger reloads and need the extra case volume.

What you are actually buying with an RMS hardware set

AeroTech RMS hardware is reusable. You buy the aluminum case and closures once, then buy reload kits for each flight. The hardware set does not include a reload, so you will need to purchase the matching reload separately. This is different from single-use motors, where the casing is part of the reload.

The size you choose locks you into a reload family. A 38mm case takes 38mm reloads, a 54mm case takes 54mm reloads, and so on. Within a size, different case lengths accept different reloads. For example, the RMS-38/1080 case is for RMS-38/1080 reloads, while the RMS-54/852 case is for RMS-54/852 reloads. You cannot swap reloads between sizes or between high power and mid power RMS lines.

29mm hardware: the small high power entry point

The 29mm size is the smallest high power RMS hardware in this comparison. It is a good fit if you fly lighter rockets and want high power certification without moving up to heavier cases. The AeroTech RMS-29 29mm 360 N-Sec Aluminum Motor Case (2936C) is a bare case for RMS-29/360 reloads. It does not include closures, so you must supply a forward closure and an aft closure separately.

There is also a smaller 29mm case, the AeroTech RMS-29/40-120 Motor Case (910813A). That case uses the 29/40-120 reload family and also requires separate closures. Note that the 29/40-120 reloads are mid power, not high power, and they are not compatible with high power RMS products. If you want to stay in high power, the 29/360 case is the one to consider, but remember that closures are an extra purchase.

38mm hardware: the practical middle ground

The 38mm size is the most versatile step up. It handles a wide range of reloads and is still manageable for many mid-size high power rockets. The AeroTech RMS-38/1080 Complete Motor Hardware Set (3810M) is a complete set: it includes the aluminum motor case, forward closure, forward seal disc, aft closure, and a 1cc tube of Super-Lube grease. Because the forward seal disc is included, you do not need to source it separately. This set is for all AeroTech RMS-38/1080 high power reload kits.

The 38/1080 case length gives you more propellant volume than shorter 38mm cases, so it suits flights where you want more total impulse. If you already own 38mm hardware from a different length, check the reload compatibility before buying; the case length must match the reload designation.

54mm hardware: larger volume for bigger flights

The 54mm size is for flyers who have moved beyond 38mm and need more case volume. The AeroTech RMS-54/852 Complete Motor Hardware Set (5485M) includes the aluminum motor case, forward closure, aft closure, and a 1cc tube of Super-Lube grease. It is for all AeroTech RMS-54/852 high power reload kits. Unlike the 38/1080 set, the 54/852 set does not list a forward seal disc in the catalog facts. If your chosen reload requires one, you will need to confirm that separately.

The 54/852 case is shorter than some other 54mm cases, so it is a reasonable entry into 54mm if you want to keep motor length and weight lower. However, if you already fly 54mm reloads that need a longer case, this set will not fit them. Always match the case designation to the reload designation.

Fit guidance: matching hardware to reloads and rockets

Fit is about three things: reload compatibility, closure requirements, and airframe size. First, the case must match the reload. A 38/1080 case takes 38/1080 reloads, a 54/852 case takes 54/852 reloads, and a 29/360 case takes 29/360 reloads. Second, check what is included. The 38/1080 and 54/852 sets include closures; the 29/360 and 29/40-120 cases do not. Third, the motor mount tube in your rocket must match the case diameter. A 29mm case needs a 29mm mount, a 38mm case needs a 38mm mount, and a 54mm case needs a 54mm mount.

Also note the high power versus mid power split. High power RMS reloads are not compatible with mid power RMS products. The 29/40-120 case uses mid power reloads, while the 29/360, 38/1080, and 54/852 cases use high power reloads. Do not mix them.

Decision rules for choosing your RMS hardware size

• If you are new to high power and want a complete set: Choose the 38mm RMS-38/1080 set. It includes the case, closures, and forward seal disc, so you only need reloads. Most versatile first high power hardware.
• If you already fly 29mm high power reloads and have closures: Choose the 29mm RMS-29/360 case. It is a bare case, so you must already own or buy the forward and aft closures separately. Only if you are committed to the 29/360 reload family.
• If you need more volume than 38mm and fly 54/852 reloads: Choose the 54mm RMS-54/852 set. It includes the case and closures but not a forward seal disc. Confirm your reload's requirements. Step up only when your reloads and rocket mount match 54mm.
• If you want mid power reloads in a 29mm case: The 29/40-120 case uses mid power reloads and needs separate closures. Do not mix it with high power RMS reloads. Keep mid power and high power hardware separate.

Product facts

• AeroTech RMS-38/1080 Complete Motor Hardware Set - 3810M: For use with all AeroTech RMS-38/1080 high power motor reload kits. This reusable AeroTech RMS-38/1080 motor hardware set includes the aluminum motor case, motor forward closure, forward seal disc, motor aft closure, and a 1cc tube of the Super-Lube grease for assembly. Motor reloads sold separately. You get a complete set with closures and a forward seal disc, so you only need to add reloads. The included grease helps with assembly.
• AeroTech RMS-54/852 Complete Motor Hardware Set - 5485M: For use with all AeroTech RMS-54/852 high power motor reload kits. This reusable AeroTech RMS-52/852 motor hardware set includes the aluminum motor case, motor forward closure, motor aft closure, and a 1cc tube of the Super-Lube grease for assembly. Motor reloads sold separately. This set includes the case and closures but does not list a forward seal disc. Confirm whether your reload requires one before flying.
• AeroTech RMS-29 29mm 360 N-Sec Aluminum Motor Case - 2936C: For use with all AeroTech RMS-29/360 high power motor reload kits. Motor reloads sold separately. This is a bare case only. You must also buy a forward closure and an aft closure to complete the motor.
• AeroTech RMS-29/40-120 Motor Case - 910813A: For use with all AeroTech RMS-29/40-120 motor reload kits. This reusable AeroTech RMS-29/40-120 aluminum motor case requires a forward closure and aft closure. Motor reloads and closures sold separately. Important: Mid Power RMS reload kits are not compatible with High Power RMS products. This case uses mid power reloads, not high power. It is a different path from the high power 29/360 case.

Best fit and not fit

Best for

• Flyers who want reusable hardware and are ready to buy reloads separately
• Flyers whose rocket motor mount matches the case diameter they choose
• Flyers who will confirm closure and seal disc requirements before flying

Not for

• Flyers who want a single-use motor with no assembly
• Flyers who are not sure which reload family they will standardize on
• Flyers who cannot verify that their reloads match the case designation