How to Use AeroTech Hobby Delay Kits for RMS-29/40-120
By Quest Q-jet | Published: 2026-10-30
Category: How-to Guides
Learn to install and adjust the AeroTech HDK-23 hobby delay kit for RMS-29/40-120 reloads. Step-by-step instructions for safe, accurate delay timing.
Quick answer
Install the AeroTech HDK-23 hobby delay kit into your RMS-29/40-120 reload by first selecting the correct delay length, then drilling the delay element to your desired time, and finally assembling the delay module with the supplied O-rings and insulators.
Why Use a Hobby Delay Kit?
The HDK-23 is designed for use with F22-7J motors and other RMS-29/40-120 reloads. It provides three delay elements and spacers, allowing you to adjust the delay time to match your rocket's weight and desired deployment altitude. Hobby Delay Kits are not interchangeable with High Power Delay Kits, so always confirm you have the correct kit for your motor system.
Important Safety Notes
Always work in a clean, well-lit area. Ensure the motor is not assembled or live during delay drilling. The HDK-23 is U.S. mailable with no hazmat fee, but the sale of high power motors is restricted to persons 18 years or older. Follow all NAR and TRA safety codes.
Step-by-Step Installation Guide
- Select Delay Length: Determine the desired delay time in seconds. The HDK-23 includes delay elements that can be drilled to shorter times. Use a delay drilling tool to remove material from the exposed end of the delay element. Each 1/32 inch (0.8 mm) removed reduces delay by about 0.5 seconds. Common mistake: drilling too fast or unevenly can cause the delay to burn erratically. Use a slow, steady drill speed.
- Assemble the Delay Module: Insert the drilled delay element into the delay housing. Place the delay insulator over the element, followed by the delay O-ring. Ensure the O-ring sits evenly to prevent gas leakage. Add spacers if needed to adjust the overall length. Checkpoint: the delay element should fit snugly but not be forced. If it's too tight, lightly sand the edges.
- Install into RMS-29/40-120 Reload: Place the assembled delay module into the forward closure of the RMS reload. Secure with the retainer ring. Ensure all O-rings are properly seated. Refer to the reload kit instructions for final assembly steps. Always test fit the delay module before final assembly to avoid binding during flight.
- Verify Delay Timing: After assembly, double-check that the delay time matches your simulation or plan. If unsure, err on the side of a longer delay to prevent early deployment. Record your settings for future reference. Common mistake: assuming the drilled delay is exact. Always allow a ±0.5 second tolerance.
Product Facts
- AeroTech HDK-23 RMS-29/40-120 Hobby Delay Kit (3-Pack) - 43523: The AeroTech HDK-23 comes with 3 rocket delay elements and spacers, plus motor delay O-rings and delay insulators. You get everything needed for multiple adjustments in one pack, saving time and ensuring compatibility with RMS-29/40-120 reloads.
AeroTech HDK-23 RMS-29/40-120 Hobby Delay Kit (3-Pack) - 43523
