Is the rocket named "DOROTHY" ?
Nice looking rocket!
Did you post the open rocket file anywhere?
Waterproofing, I used Silicone Conformal Coating (one coat), except on power connectors. But with salt water, conditions are different because it conducts. Silicone Conformal coating you could still use, but you'd need to "liquid" tape the power connectors too.
Why pick a rocket with canards for this? Useless drag, all it does is reduce peak altitude.
Over the duration of the rocket’s upward flight, I would question whether an internal thermometer would be sensitive (fast responding enough) to plot very many TEMPERATURE data points.
Hope you had a good “snooze” as my Dad says.There are a number of questions that I'd like to pose to the builder. Price point I'm guessing. The kit's not very expensive. I don't know if there's a thermometer in there or not. I'll ask... Later... After I get some sleep.
What?! Aerotech F32-X just as one example.Q: Why a cluster? A: From their experiments, single motor rockets (even with larger motors) don't seem to have the oomph to punch the rocket through the winds into the region of the tornado they need it to be in. Also, due to restrictions from state to state regarding rockets, going with LPR is less restrictive than using larger, more powerful motors.
What?! You don't need folding swing-down fins as used with military 2.75" FFARs which might need to be metal although there is a not very well done 3D printed example designed by someone else that I've posted a link to in the 3D printing forum. I'd use a 3D printed ABS fixed and swept 6 or 8 fin base fin can within 2.5" or 3" PVC pipe. Mid-section 3D printed ABS, highly swept, tiny chord "fins" (almost whiskers) for maintaining centering in the tube with virtually no effect of moving CP forward. There are several ways I can think of to keep the tube sealed with failsafe removal even in high winds before launch, the best method being determined experimentally.Q: Why not a preloaded tube launched system? A: Reed wants to have be able to have 10 rockets ready to fire, but the only tube launched systems we could find use metal fins, and due to weight limitations (from the motors), that's not an option.
What?! Aerotech F32-X just as one example.
What?! You don't need folding swing-down fins as used with military 2.75" FFARs which might need to be metal although there is a not very well done 3D printed example designed by someone else that I've posted a link to in the 3D printing forum. I'd use a 3D printed ABS fixed and swept 6 or 8 fin base fin can within 2.5" or 3" PVC pipe. Mid-section 3D printed ABS, highly swept, tiny chord "fins" (almost whiskers) for maintaining centering in the tube with virtually no effect of moving CP forward. There are several ways I can think of to keep the tube sealed with failsafe removal even in high winds before launch, the best method being determined experimentally.
Yes, with measuring G-limits perhaps too low to monitor rocket G-forces while under thrusting of a high average thrust motor, but not even remotely close to the level of damaging levels of G-forces of any MEMS accelerometer I've ever seen specs for. The accelerometer may saturate, but only for a very short period of time and it will not be damaged in any way. If I had the total mass of their electronics I could sim it to see if the Gs even reach the 16G limit of many common MEMs accelerometers (I'm not looking at the specific one they're using while typing this, so it may have another common limit - 8Gs). If MEMs accelerometers were that fragile, imagine what would happen to the one in your smart phone with probably a 2G limit if you dropped it.He said that ChasinSpin's sensors have G limits...Breaking them as they come off the launch rod would be costly and counterproductive.
We also have to remember that the opportunities to safely test these things in those conditions are few and far between. There is also the issue of Canadian laws/licensing to remember, Curtis is in Canada, and is reliant on items he can source there.
Yeah, but I'll be the first to admit that a sealed, weatherproof, field swappable, tube launched system adds a large number of complexities and issues that need to be addressed versus the much greater simplicity of the usual launch rod method. It just makes me cringe to think of two sharp metal rods pointed skyward on top of a vehicle in close proximity to a violent storm. If they don't have one already mounted on top of the Dominator, they should install an atmospheric electrometer to possibly see if a strike is imminent. It could serve another very useful scientific purpose if its data is logged with their GPS position and the time: electrostatic field data under the storm. Also, it could serve as a warning alarm when they're outside the vehicle. The professional versions require a very good earth ground, but that's not possible. However, some amateur DIY ones not meant for extreme accuracy that I've seen on-line do not.Looks like you got him there... They were thinking of rockets with fins that wrap around the body tubes inside of the rocket and deploy at launch.
Yeah, but I'll be the first to admit that a sealed, weatherproof, field swappable, tube launched system adds a large number of complexities and issues that need to be addressed versus the much greater simplicity of the usual launch rod method. It just makes me cringe to think of two sharp metal rods pointed skyward on top of a vehicle in close proximity to a violent storm. If they don't have one already mounted on top of the Dominator, they should install an atmospheric electrometer to possibly see if a strike is imminent. It could serve another very useful scientific purpose if its data is logged with their GPS position and the time: electrostatic field data under the storm. Also, it could serve as a warning alarm when they're outside the vehicle. The professional versions require a very good earth ground, but that's not possible. However, some amateur DIY ones not meant for extreme accuracy that I've seen on-line do not.
Was thinking about the tube launched system some more... Other members of The Rocketry Forum (TRF) and I have been chatting... One big problem we see is having you get outside of the Dominator with, basically, a lightning rod sticking up and out of it.
If you were to mount a rail inside a tube, you wouldn't have to exit the shelter of the Dominator to launch. Done properly, you don't need to have the fins actually touching the side of the tube, nor even have whiskers mounted to the rocket. The rail still could act as a lightning rod, but you don't even actually have to physically be touching it to deploy and launch your rocket. When stowing the unit, you also have a plastic shield preventing you from coming in direct contact with the metal.
Using my idea of an aerodynamic faring, shielding the open launch tube(s), you could reduce the possibility of the wind damaging the rockets in transit. If the rocket has been made water resistant (using wood hardener) and a sealed motor is pre-loaded water shouldn't be an issue, and perhaps a flap of rubber (from an old bike inner tube) could be used to keep things from entering there.
While you're traveling, the fairing would keep the direct wind, and hail out of the tube, but when when the rocket is needed, moving the tube into firing position opens it to the sky. "Whiskers" made from piano wire installed inside the tube could help hold the rocket still (reducing wear on the rocket) while you are in transit, but still be loose enough to not affect the launch. Basically, those whiskers don't even have to touch the rocket when you're parked, they would just prevent the rocket from moving more than a millimeter, or so, from side to side, while in transit. Another advantage is that they wouldn't add weight to the rocket.
Another concern is the launch controller. You don't want wires leading from the rocket directly to you. One lightning strike and you could have a very bad day. In the PBS NOVA Lightning program I mentioned (which has apparently been since been deleted or blocked on YouTube in the US), I remember hearing that the scientists use a pneumatic system made from plastic to "press" the button. Thus, there's no direct metal contact to them that could cause injuries should a strike result from their activities.
I now understand that space is cramped inside the Dominator, perhaps a "bike rack" mounted to the back hatch could allow you to hold multiple tubes (with rockets). Those could be pre-loaded, and locked inside their own launch tubes, and secured to the Dominator for easy access (provided you have the key to unlock it), while also keeping curious fingers out of your equipment. A "Remove Before Flight" pull pin could be used to activate the sensor package when the units are ready to launch. Done properly, you could have the launch tube held on the launcher with clips that don't even need to be locked, they are clipped into place using a couple of C shaped pieces of spring steel on the launcher. You could launch, remove the expended tube, slap a fresh tube in its place, connect your electrical system, pull pins, get back inside the Dominator, and repeat as often as you want to.
Yes, with measuring G-limits perhaps too low to monitor rocket G-forces while under thrusting of a high average thrust motor, but not even remotely close to the level of damaging levels of G-forces of any MEMS accelerometer I've ever seen specs for.
Based upon the very high Gs experienced by commercially available sensors with SMD electronics and lipo packs long-used in HPR, you have nothing to worry about for properly connected electronics intended for high Gs. If you want it there fast, use a high average thrust motor like, as one example, an Aerotech F32-X. Also, if you are wanting to aim for a specific target, study rocket design for minimum weathercocking and greatest stability in high winds. What is being used isn't that.That's correct, I wasn't concerned about the G-limits of the Mems sensor. It's rated to +-8G for data, and 2000G (<1.0mS). So although it doesn't completely quantify the launch phase (forces are slightly over 8G), it's purpose is to measure forces in the Tornado in flight (which it's within spec for).
In general, we're concerned about G forces however as any mass of electronics / battery can have failure scenarios under high G, we mitigate these,
but limiting G forces is a prudent practice. Additionally we don't require (or want) the rocket to go high, but we need it to get there fast.
We also had limitations on the Inertial Management Units we could choose from given the speed we were traveling at the quality of data we required and size/weight constraints. The first prototype, testing showed that sensor couldn't keep up with the speed and resolution we needed, so we had to replace with a better sensor. (the one we launched with).
All data is sampled at 10Hz, except GPS which peaks out at 5Hz, and Battery (1Hz)
Enter your email address to join: