Paul Lavin, our general manager, (aka Captain Tetrahedron) has probably launched several hundred (if not a thousand or so) rockets. He's seen some amazing flights by friends and customers but he was never so amazed as he was yesterday on the occasion of his 18 year old daughter Gaby's Level 1 flight attempt. "Every time you launch a rocket you learn something. Sometimes you get the rocket back" is our favorite nugget of rocketry wisdom. There is learning aplenty still to be had no matter how many rockets you fly.
Gaby's 12 inch Art Applewhite saucer was prepped with a Pro38 H impulse motor and mounted on the rod. Saucers were the best bet for a successful flight on the day owing to a strong breeze blowing out of the north... unless you like long walks in the country. You can almost always fly an HPR saucer when it is inadvisable to fly anything else on a motor bigger than a D.
At the pad was the Gaby (the flyer), the UKRA Range Safety Officer, and the owner of the launch controller being used. The good Cap'n was there, too, as officiating Tripoli Rocketry UK prefect/safety monitor for the rocket preparation and flight observation (and not just in proud dad mode). This was rather a larger crew than usual.
They were using the Cap'n's pad but a mate's home-brew launch controller which had launched many model flights previously (and a few hybrid static tests too) was pressed into service. The Cap'n's own controller was at home getting recharged.
Always conscious of safety (even if it isn't his daughter involved) the Tripoli Rocketry UK Prefect asked "Is the key out?" At the affirmative, Cap'n Tetrahedron turned away from the launch crew and was about to return to the club tent to complete a bit of paperwork (as well as escort a curious young visitor back behind the safety line). Gaby took the safety sleeve off the igniter end. She handed one wire over to be clipped, handed over the second wire... and the rocket left. An H motor from three feet away is loud!
No one was hurt. After everybody checked to make sure their sphincters were still set to full off, we set about discovering the cause of the departure without benefit of countdown. The rocket, which had an otherwise uneventful flight, provided no clues. It was recovered intact (and flew again an hour later for its second cert flight of the day).
The old standby test of touching the controller leads together to see if there was a spark showed negative... and proved conclusively that the old standby test is NOT safe and should not be relied on to reveal if the controller is in fact dead.
Cap'n T then did something that he rarely does with igniter clips, he put them in his mouth. They tingled! The controller was live with the key out! This was confirmed more precisely with a multimeter.
The startling thing was that only ONE of the igniter leads was clipped to the controller at the time of the impromptu launch. When the flyer handed the other lead to the controller owner, his bare fingers completed the circuit. We were all surprised to say the least!
We tested everyone's conductivity at the pad side. We were all good for 8 volts when holding a controller clip and a meter probe barehanded. Under the circumstances, the rocket would have left without benefit of countdown if the second clip had touched the wire but it was completely unexpected that it launched with only one lead attached to the controller!
The good Captain himself has used a home-brew controller for years. The only launch anomalies arose from corroded clips which is a tolerable failure mode for safety if a bit discourteous to others waiting to fly. Deepsky offers Estes Electron Beam II, Pratt Hobbies Go Boxes and, at the top end, Pratt Hobbies Sure Fire III and HyperTEK hybrid launch gear for firing igniters. They can all be counted on but still should be tested before connecting to an igniter.
Some flyers, for creative or budgetary reasons, choose to roll their own launch controllers. Home-built controllers are NOT bad and should not be banned but each one needs to be proven safe before use. Even manufactured controllers cannot be assumed to be safe until tested! Any controller, if they are dropped, rained on, exposed to conductive dust, etc., can function in unexpected ways... or not at all! Every launch controller should be tested safe before every launch meeting. If the RSO doesn't insist, do it yourself for your own safety!
If you have a name brand, store-bought controller, please RTFM. Then test the controller before you use it in anger. It's far better to expend a spare igniter in the back garden than create more washday drudgery for mum after a launch event! Test your launch controller EVERY TIME it is installed at the launch site and if you are in any doubt, stick the clips in your mouth! Or better yet, given the domestic livestock and wildlife that we share fields with, use a multimeter or light bulb to test it instead.
If you are flying clusters, be aware that the current requirements of multiple igniters is higher than just one igniter (duh?) and that is usually more than 4 x AA cells can provide. We had a couple of demonstrations of asymmetric thrust yesterday as well, off another controller. Bad ignition is usually the fault. Deepsky favours QuickMatch for model cluster flying but HPR clusters demand a more technical approach. Test!
If you are intent on building your own controller, use good, high rated components AND get some advice. Then build it and test it and then test it again before you use it! Make sure that no internal wires can move and cause a short thereby creating a live controller even if the key is out and/or the battery isolation switch is set to off. Shake it and test!
Assuming the pad doesn't blow over or the rocket's fins come off, the most dangerous phase of a launch comes when you attach the igniter to the clips. You will undoubtedly be well short of the ordained safety distance and probably facing the rocket, to boot. That's why only the flyer and necessary launch and safety personnel should congregate at the pad when there are live rockets present.
After similar incidents last year, the UK Rocketry Association's Safety and Technical Committee released a detailed treatise on igniter and controller safety. While UKRA speaks to HPR flyers, their advice has merit for model flyers, too. Their note will be reproduced (with permission granted) in the Deepsky Tech Tips page.
Continuity checking should be done with the igniter OUT of the motor. Built-in continuity equipped controllers should only use that continuity feature as part of a countdown sequence when the igniter is installed. If you have a controller with a pad-side relay, be sure you can isolate the battery from the circuit. An audible alarm for a live circuit isn't a bad idea. LEDs in bright sunlight can be overlooked. Test them to be sure you can see them.
Sometimes you don't even need a controller to launch a rocket. Synthetic fabrics in dry winter air can generate a lot of static electricity. A good zap could produce an unanticipated whoosh from a model rocket or set off a sensitive HPR igniter. Afterwards, Captain T realised that he was carrying a Bluetooth phone and headset to the pad yesterday. It wasn't a factor but RF sources near igniters or on-board flight controllers aren't a great idea. Leave your phone in the car!
And of course, it goes without saying (but still worth banging on about): No smoking in the prep area, while you are carrying a rocket, or at the pad. And maybe there isn't any real safe time/place to smoke while building or painting a rocket, either, eh?
The best launches are always preceded by a loud and clear count down from the required safe distance and are not followed by a need to freshen your linens.
Fly safer!
Team Deepsky
Gaby's 12 inch Art Applewhite saucer was prepped with a Pro38 H impulse motor and mounted on the rod. Saucers were the best bet for a successful flight on the day owing to a strong breeze blowing out of the north... unless you like long walks in the country. You can almost always fly an HPR saucer when it is inadvisable to fly anything else on a motor bigger than a D.
At the pad was the Gaby (the flyer), the UKRA Range Safety Officer, and the owner of the launch controller being used. The good Cap'n was there, too, as officiating Tripoli Rocketry UK prefect/safety monitor for the rocket preparation and flight observation (and not just in proud dad mode). This was rather a larger crew than usual.
They were using the Cap'n's pad but a mate's home-brew launch controller which had launched many model flights previously (and a few hybrid static tests too) was pressed into service. The Cap'n's own controller was at home getting recharged.
Always conscious of safety (even if it isn't his daughter involved) the Tripoli Rocketry UK Prefect asked "Is the key out?" At the affirmative, Cap'n Tetrahedron turned away from the launch crew and was about to return to the club tent to complete a bit of paperwork (as well as escort a curious young visitor back behind the safety line). Gaby took the safety sleeve off the igniter end. She handed one wire over to be clipped, handed over the second wire... and the rocket left. An H motor from three feet away is loud!
No one was hurt. After everybody checked to make sure their sphincters were still set to full off, we set about discovering the cause of the departure without benefit of countdown. The rocket, which had an otherwise uneventful flight, provided no clues. It was recovered intact (and flew again an hour later for its second cert flight of the day).
The old standby test of touching the controller leads together to see if there was a spark showed negative... and proved conclusively that the old standby test is NOT safe and should not be relied on to reveal if the controller is in fact dead.
Cap'n T then did something that he rarely does with igniter clips, he put them in his mouth. They tingled! The controller was live with the key out! This was confirmed more precisely with a multimeter.
The startling thing was that only ONE of the igniter leads was clipped to the controller at the time of the impromptu launch. When the flyer handed the other lead to the controller owner, his bare fingers completed the circuit. We were all surprised to say the least!
We tested everyone's conductivity at the pad side. We were all good for 8 volts when holding a controller clip and a meter probe barehanded. Under the circumstances, the rocket would have left without benefit of countdown if the second clip had touched the wire but it was completely unexpected that it launched with only one lead attached to the controller!
The good Captain himself has used a home-brew controller for years. The only launch anomalies arose from corroded clips which is a tolerable failure mode for safety if a bit discourteous to others waiting to fly. Deepsky offers Estes Electron Beam II, Pratt Hobbies Go Boxes and, at the top end, Pratt Hobbies Sure Fire III and HyperTEK hybrid launch gear for firing igniters. They can all be counted on but still should be tested before connecting to an igniter.
Some flyers, for creative or budgetary reasons, choose to roll their own launch controllers. Home-built controllers are NOT bad and should not be banned but each one needs to be proven safe before use. Even manufactured controllers cannot be assumed to be safe until tested! Any controller, if they are dropped, rained on, exposed to conductive dust, etc., can function in unexpected ways... or not at all! Every launch controller should be tested safe before every launch meeting. If the RSO doesn't insist, do it yourself for your own safety!
If you have a name brand, store-bought controller, please RTFM. Then test the controller before you use it in anger. It's far better to expend a spare igniter in the back garden than create more washday drudgery for mum after a launch event! Test your launch controller EVERY TIME it is installed at the launch site and if you are in any doubt, stick the clips in your mouth! Or better yet, given the domestic livestock and wildlife that we share fields with, use a multimeter or light bulb to test it instead.
If you are flying clusters, be aware that the current requirements of multiple igniters is higher than just one igniter (duh?) and that is usually more than 4 x AA cells can provide. We had a couple of demonstrations of asymmetric thrust yesterday as well, off another controller. Bad ignition is usually the fault. Deepsky favours QuickMatch for model cluster flying but HPR clusters demand a more technical approach. Test!
If you are intent on building your own controller, use good, high rated components AND get some advice. Then build it and test it and then test it again before you use it! Make sure that no internal wires can move and cause a short thereby creating a live controller even if the key is out and/or the battery isolation switch is set to off. Shake it and test!
Assuming the pad doesn't blow over or the rocket's fins come off, the most dangerous phase of a launch comes when you attach the igniter to the clips. You will undoubtedly be well short of the ordained safety distance and probably facing the rocket, to boot. That's why only the flyer and necessary launch and safety personnel should congregate at the pad when there are live rockets present.
After similar incidents last year, the UK Rocketry Association's Safety and Technical Committee released a detailed treatise on igniter and controller safety. While UKRA speaks to HPR flyers, their advice has merit for model flyers, too. Their note will be reproduced (with permission granted) in the Deepsky Tech Tips page.
Continuity checking should be done with the igniter OUT of the motor. Built-in continuity equipped controllers should only use that continuity feature as part of a countdown sequence when the igniter is installed. If you have a controller with a pad-side relay, be sure you can isolate the battery from the circuit. An audible alarm for a live circuit isn't a bad idea. LEDs in bright sunlight can be overlooked. Test them to be sure you can see them.
Sometimes you don't even need a controller to launch a rocket. Synthetic fabrics in dry winter air can generate a lot of static electricity. A good zap could produce an unanticipated whoosh from a model rocket or set off a sensitive HPR igniter. Afterwards, Captain T realised that he was carrying a Bluetooth phone and headset to the pad yesterday. It wasn't a factor but RF sources near igniters or on-board flight controllers aren't a great idea. Leave your phone in the car!
And of course, it goes without saying (but still worth banging on about): No smoking in the prep area, while you are carrying a rocket, or at the pad. And maybe there isn't any real safe time/place to smoke while building or painting a rocket, either, eh?
The best launches are always preceded by a loud and clear count down from the required safe distance and are not followed by a need to freshen your linens.
Fly safer!
Team Deepsky
