A high-power model rocket, for the purposes of our field procedures, is any rocket with an H (>160 N-Sec of impulse) or larger engine or a combination of engines (clustered or staged) with a total impulse greater than 360 N-sec (3 G engines). Any rocket weighing more than 1500 grams. Any rocket using rocket engines not classified as model rocket engines per NFPA 1122, such as having an average thrust in excess of 80.0 Newtons, containing in excess of 125 grams of propellant, hybrid rocket motors, and sparky motors.
For the most part, the high-power procedures are similar to the low-power procedures so familiarize yourself with the low power procedures first. The high-power procedures have the following differences from the low-power procedures.
- You use high-power flight cards.
- The safety check is done by the High-power Safety Check Officer.
- The safety check is more rigorous.
- You use the high-power pads (Racks 5 and 6) or the away pad for M launches.
- You must have a NAR or Tripoli license for the engines you are flying.
- For H and higher launches a Class III Pyro must be present.
- High-power rockets are only flown at Snow Ranch.
- For M launches, you must have prior board approval.
Table of contents
For launches containing M engines, you must have prior approval of the LUNAR board. This should be done a week or two before the launch to give the board a chance to review and approve your plans. It is also necessary to insure that the away pad is brought to the launch. Contact the lunar officers bu emailing to officers at lunar.org.
NAR or Tripoli License
To purchase or fly H or larger engines, you must have a license issued by one of the two model rocketry organizations: National Association of Rocketry (NAR) or Tripoli. The licenses come in 3 levels, depending on the size of engines you want to buy and fly.
- Level 1 allows the purchase and use of H and I impulse class engines; solid and hybrid. Certain F and G engines may also require Level 1 certification for purchase and use.
- Level 2 allows the purchase and use of J, K, and L impulse class engines; solid and hybrid.
- Level 3 certification allows the purchase and use of M, N, and O impulse class rocket engines; solid and hybrid.
Each level of license requires you to demonstrate additional knowledge and skill on how to safely build and fly High-power rockets. See the section on obtaining licenses for more information.
Class III Pyro
For any use of "H" high-power motors at a club launch, at least one pyro must be in attendance. A pyro is a person who holds a California Class III Pyrotechnic Operators license. While this is generally the case it is not guaranteed.
Using the High-power Flight Cards
The high-power flight cards are significantly different from the low-power ones. In addition to places for the rocket name, manufacturer, and engine, they also have places for igniter type, engine retention, stability criteria, recovery method, and projected altitude. On the back of the card are checkoffs for all the safety checks made by the HP-SCO.
The LUNAR high-power flight card collects a lot more information about the construction and stability of the rocket. On the back is a checklist for the safety check.
High-power Safety Check
The most serious change in the procedures from those for model rockets is in the safety check. The high-power procedures are based on those used by NAR, Tripoli and other clubs that fly a lot of high-power rockets. The safety check is done by the HP-SCO who is an experienced, high-power rocketeer.
The HP-SCO first checks the structural integrity of the rocket, including:
- Attachment of the fins
- Attachment of the engine mount
- Recovery system attachments to nose cone and rocket
- Packing of the parachute
- Fit of the nose cone.
The next step is to check the stability of the rocket. If the rocket is a kit, we will accept that the rocket is stable if built to the kit's specifications. If the rocket is not a kit, the flier will have to present some sort of documentation to show the location of the center of pressure (CP) so it can be compared to the location of the center of gravity (CG). The CG should be at least one caliber (body tube diameter) ahead of the CP to assure good stability. Rockets that do not conform to this rule will need compelling evidence to convince the HP-SCO that they are stable. The RSO has the final say in any dispute over the flight-worthiness of a model.
The next step is to insure that the engine is safe and appropriate for the high-power model being flown. The HP-SCO checks the type of engine and verifies that it is on the list of NAR certified engines. Only engines certified by the California Fire Marshal are allowed at club launches. The HP-SCO weighs the rocket and compares the launch weight to the recommended maximum weight for the engine. The HP-SCO uses an altitude chart to compare the maximum altitude and the appropriateness of the delay.
The altitude charts are in the Appendix. The charts plot the maximum altitude and time to maximum altitude and delay to maximum altitude (time minus propellant burn time) versus launch weight for different engines.
For high powered rockets with electronic initiation of upper stages or of the recovery system, the HP-SCO checks the electronics to see that they are in good order. Specifically, the HP-SCO checks the condition of the:
- Recovery system electronics
- Staging electronics
All high-power launches are "heads-up" launches.
When all safety checks are complete, the HP-SCO checks off the appropriate boxes on the launch card and assigns the rocket a pad by placing the launch card on the clipboard in the appropriate spot for the pad number assigned to the rocket.
Load Your Rocket on the Pad
When the safety check and pad assignment are complete check to see if the high power rack you have been assigned to is open for loading. If it is, go over and load your rocket. All sizes of launch rods from 1/8 to 1/2 inch are available, and are stored in the white tube. We also have several launch rails. All the launch rods and rails are completely interchangeable on all the pads.
==Picture of a hitgh power pad ==
One of the high power pads.
The launch clips are on a short piece of cord and are interchangeable with the cords on all our pads. We have launch clips with two alligator clips or with Aerotech Copperhead clips. Choose the clips that fit your igniter. The remote launch box has continuity checkers for each of the pads. See that the LED for your pad is lit, indicating that the continuity is good.
=picture of the pad controller showing the continuity checker leds
Continuity checker LEDs on the remote launch box.
When all the pads are loaded, the LCO closes the pads. He then enables the remote launch box. A beeper in the box sounds when the box is enabled as a warning to bystanders. Do not go near the pads whenever the box is beeping. If all goes well, the LCO launches your rocket and you get to chase it. If your rocket does not fly for some reason, the LCO may let you go back and try to fix it. If we are busy, he will give you back your launch card and ask you to remove your rocket so that others can launch while you are fixing things.