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(October 7, 2011 – Cuyahoga Falls, OH)
The launch agenda for 10/8/11 will include two launches from “Pathfinder”, the X2 Artemis rocket built for dual deployment research, and dual deployment in a form factor pretty rare in model rocketry. I have enough gear on-hand for an additional launch as well. All flights will be under F-24 power. The first launch is set for around 10:30 AM.
Also on the list will be at least three flights from Aurora X5 “Firefly”. The second flight (and possibly a third one) is planned as my first ever night launch. First launch will be an evening launch with the rocket camera on board. The second will be at dusk using the night flight gear. The final launch will be after sundown.
I will be posting updates via Twitter on this one! Stay tuned in!
Information if you are free to come see the fun posted here!
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Welcome to part two!
At this point, the paint scheme is done, and you are now able to see the rocket take shape. Artemis X2-05.
The next step in the development cycle is the set up to test all the ejection systems.
The ejection charge canisters are made from small sections of styrene tubing with a Quest G2 igniter epoxied to one end. The ejection charges are behind an ejection baffle system specifically designed to work while being extremely close to the charge canister.
This requirement of mine introduced more variables to contend with, which made for interesting times!
Drogue parachute deployment system
The first of the interesting steps involves getting the drogue chute charge canister behind an ejection baffle which is shared with the charge on the engine.
The engine’s ejection charge is used as a backup in the event something goes wrong with the electronics. My solution to the shared baffle dilemma was to place a compartment on the lower half of the rocket which gives access to the shared baffle system. The access door uses rubber silicone to seal the compartment so that the pressure is directed towards the area of interest, and not just leak out of the door.
The empty compartment for the drogue parachute ejection canister.
Inside the compartment is an area for the connections to “live”, and another for the charge to sit in. There is a small hole which allows the charge to slip into.
In the picture of the loaded compartment, you can see the ejection charge canister to the lower right side of the compartment.
The drogue chute ejection canister is installed.
Behind it is a scrap plastic piece to prevent the recoil forces from pushing the canister back out of the opening. On the upper side of the compartment you’ll see the electrical connections.
Main parachute deployment section
The upper baffle for the main parachute deployment system was challenging in some ways, but easier to implement than the drogue. For one, there is no need to share the baffle system with the motor.
The canister for the main parachute lives just above the electronics bay. There is another part that serves as the mount for that ejection charge. The main charge fires sideways, so to prevent that force from blowing a hole int he side of the rocket over time, there is a thin aluminum shield piece to protect the body tube.
The "business end" of the main deployment baffle...
The moment of truth.
Two days before the maiden flight, I put Pathfinder through its paces in a series of ground tests designed to see if everything works as planned, and to hopefully expose any weaknesses in the design I may have overlooked. The ground tests went well – proving the designs worked well. One weakness that was exposed was the friction fit between the top of the electronics bay and the upper baffle. A minor change to the design to allow for taping the two sections together with a bit of aluminum tape solved the issue.
httpv://www.youtube.com/watch?v=R9X1MkpH8HM
So, now, as the countdown ticks away to the October 8th maiden voyage, I’m off to address a ton of loose ends!
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During the last couple of months, I’ve been designing and building the rocket destined for the next series of test flights that will pave the way to the future of my model rocketry efforts. A variation of the Artemis rocket design was chosen for these missions.
My initial choice was to build another X4 rocket for this purpose to be called “Vega”. After the results of Zephyr’s single deployment test flights, I decided to go a different route to cut the development cycle considerably, and go for the much simpler to build “Artemis” design. This allowed for more time to be spent developing the new technology.
The Artemis design was also picked as it is a design I am very familiar with, and have lots of flight data as it is the oldest / longest flying design in my fleet of rockets.
The new Artemis rocket is called “Pathfinder”. It’s name was chosen for the role it will play in my efforts to develop active electronic (computer) systems to control various events during the mission of a rocket flight. Pathfinder will also be the first of the Mid-Power rockets in my fleet to employ a full dual deployment recovery system.
Artemis DD "Pathfinder" after the first coat of paint...
Pathfinder will fly its missions using a variation of the flight test configuration known as Artemis 1B (the test flight configuration that X2-01 “Big Red” used in April / March of 2010).
(Illustration 1) Artemis 1B takes to the skies for the second time
Beginning in October, and going through November, Pathfinder will fly a series of missions designed for me to “get the feel” for Dual Deployment flights, and to clear the path for the first flight of Perseus X6-01 (AKA, Perseus V) “Nesaru”, and my NAR Level 1 certification attempt.
Dual deployment is a method used in high power rocketry where a smaller (drogue) parachute is deployed at apogee (peak altitude of the rocket’s trajectory). This parachute slows the rocket somewhat, but not slow enough to drift with the upper winds aloft. This is an important feature as high power rockets tend to reach apogee at a mile or more above ground level.
At a predefined lower altitude, the main parachute (a much larger one) is deployed to slow the rocket to a safe landing speed. All of this is accomplished with the use of electronics that monitor the altitude of the rocket during flight.
Dual deployment techniques allow for rockets to reach high altitudes, and still land somewhere close to the launch point.
While very common in high power rocketry, the use of this type of electronic systems is very rare for lower-mid power rockets such as the ones in my fleet. This is due to the complexityof the systems involved along with the limited space available in lower / mid power rocketry.
The maximum body diameter of the Artemis rockets (and all of my others for that matter) is only 41.6 mm. Whatever techniques I employ has to be very small in size…and fairly lightweight.
(Illustration 2) A breakdown of the components that make up the Artemis DD stack. This is a view before the rocket was painted. (Click image for a larger view.)
(Illustration 3) Electronics bay for Artemis Dual Deploy.
Typically, the electronic systems used in dual deployment rocketry employ the use of 9 volt batteries. I have deemed such batteries to be too much weight for class 1 rocketry. The Artemis DD makes use of the “A-23” 12 volt battery to power its systems. Small, and lightweight, it’s perfect for lighting the Quest G2 initiators used to deploy the parachutes.
One of the interesting aspects of this project for me is the fact that this is a VERY different way of thinking about model rocket design. No longer is the rocket a hollow tube with a nosecone, fins, and an engine. The “tube” is now a stack of “systems” each with a purpose, and each section is as complicated to engineer & build as one of my entire X4 or X5 rocket designs.
Illustration 2 (above) displays each of the sections of the Artemis Dual Deploy (DD) rocket stack.
Pathfinder features two ejection baffles in its design – one for the drogue chute, and the other for the main parachute.
The electronics bay was designed over a period of a few months before I came up with a miniaturized version of the bigger bays used in high power rocketry.
The altimeter used in Pathfinder is the Perfect Flite Stratologger.
The size of the stratologger JUST fits inside the BT-60 avionics bay.
Old computer type connectors are used for quick connect plugs to the igniters.
a tight fit inside the electronics bay!!
There is also a quick connect jack on the outside of the E-Bay switch ring for attaching to the external conduit that runs down the side of the booster to trigger the igniter that is behind the drogue ‘chute ejection baffle.
When the drogue chute is deployed, this connector becomes disconnected, allowing the two sections to separate. This concept was tested on Perseus Zephyr’s electronic (single) deploy test flights a couple of months ago.
That’s it for part 1. In part 2, I’ll unveil Artemis “Pathfinder” with its paint scheme, and share information about the ground testing!
The Stratologger EXPOSED!
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