thomas
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- Dec 16, 2011
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I have the plan to be the first one to certify TRA L3 in Germany .
We have several L3 flyers but afaik they all did their certification flights in Switzerland.
Now that we have a TAP in Germany, it will be possible to certify here although we have some strickt bounding conditions.
The most important one is, that the rocket start weight must be below 25 kg (55 lbs), above that you need to get a license like for an real airplane.
We get only waivers up to 2.5km (8200 feet). The fields are also pretty small so that dual deployment is mandatory for anything above 1000 meter (3200 feet). And flights above mach speed are also prohibited.
So the rocket will be heavy to fly low and slow.
The basic design is a extended Formula 150 from rocketry warehouse 3.3m (10 feet) long, I might shorten this if there is enough space for the parachutes.
All rings of the fincan and beams are made out off 4 mm Birk Plywood with 8 layers unless otherwise mentioned.
The 2 cm width beams along the flight axis hold the fins.
They have cutouts over half their width for the centering rings which have according cutouts. Therefore beside holding the fins they also stabilize the centering rings along the flight axis and determine their spacing.
Here are some of the centering rings and the beams stabilizing the fins:
The fins have cutouts for the centering rings up to 1 cm below the bodytube.
The centering rings have according 1 cm cutouts. As the beam the fins therefore act as stringers stabilizing the centering rings.
The first and last ring are made out of 6 mm Birk plywood with 12 layers with 3 mm groves for the fins from the motortube to the bodytube. They align the fins more precise than the beams can do.
Together with the centering rings this also prevents any canting of the fins along the flight axis.
The wooden beams will be laminated with strips of glass fiber cloth and epoxy to the motortube. All other parts are glued together with epoxy.
The second last ring is only 3 mm thick but has a 1 mm G10 enforcement. It has 4 holes for M4 threaded rods which prolongate through the last centerring ring and are used to connect the thrustplate.
To strengthen the whole fincan it will be filled with 2k PU foam, the centering rings have holes to allow foam to expand through them.
The thrustplate consits of 6 mm G10 with a 2.5 mm deep groove on its outer edge so that it can be plugged inside the bodytube. It is not glued in but hold in place by 4 M4 nuts, which are connected with threaded rods to the second last centering ring. The thrustplate has a 2.5 mm deep cutout for the motortube. It also holds the 75 mm flanged Aeropack retainer which is held in place by 12 M4 screws connected through the thrustplate to KFS2-M4 PEM self clinching nuts. The holes for the M4 screws normally 4.2 mm in diameter have 2.5 mm deep enlargements to 6.4 mm to press-fit the KFS2-M4 PEM nuts. The nuts are pressed in place by a vise, while a installed screw is used for alignment.
The nosecone is unchanged from the rocketry warehouse formula 150 kit.
It consist of filament wound fiberglass with an Aluminum tip and has a Von Karman shape. The nosecone itself is 864 mm long an weights 2025 g. It is connected to the rocket by a 235 mm long coupler tube from which 150 mm protrude into the main body tube. A second ebay carrying a separate tracker for the nosecone is installed in the coupler. The ebay consist of two 3 mm thick G10 rings, which have 1 mm (closer to front) and 1.5 mm grooves aligning them in the coupler. They are connected by 4 M6 threaded steel rods. The ring closer to the front is open to allow the antenna of the tracker to protrude into the nosecone. The bulkhead closing the coupler tube has a M8 U-bolt for attachment of the drogue recovery gear. The electronic bay is 1 mm thick G10 which is connected to the M6 rods trough 15x15x2 mm aluminum angles. The tracker is an Altusmetrum TeleGPS which is hold in place by 4 M3 nylon screws. It is powered by a 1000 mAh 1s Lipo secured with tire warps to the sled. An Altimax MagSwitch is used for switching. The Antenna of the TeleGPS is aligned by a Plexiglas tube. The coupler is glued into the nosecone together with the upper bulkhead. It is further secured by six 3\,mm bolts.
We have several L3 flyers but afaik they all did their certification flights in Switzerland.
Now that we have a TAP in Germany, it will be possible to certify here although we have some strickt bounding conditions.
The most important one is, that the rocket start weight must be below 25 kg (55 lbs), above that you need to get a license like for an real airplane.
We get only waivers up to 2.5km (8200 feet). The fields are also pretty small so that dual deployment is mandatory for anything above 1000 meter (3200 feet). And flights above mach speed are also prohibited.
So the rocket will be heavy to fly low and slow.
The basic design is a extended Formula 150 from rocketry warehouse 3.3m (10 feet) long, I might shorten this if there is enough space for the parachutes.
All rings of the fincan and beams are made out off 4 mm Birk Plywood with 8 layers unless otherwise mentioned.
The 2 cm width beams along the flight axis hold the fins.
They have cutouts over half their width for the centering rings which have according cutouts. Therefore beside holding the fins they also stabilize the centering rings along the flight axis and determine their spacing.
Here are some of the centering rings and the beams stabilizing the fins:
The fins have cutouts for the centering rings up to 1 cm below the bodytube.
The centering rings have according 1 cm cutouts. As the beam the fins therefore act as stringers stabilizing the centering rings.
The first and last ring are made out of 6 mm Birk plywood with 12 layers with 3 mm groves for the fins from the motortube to the bodytube. They align the fins more precise than the beams can do.
Together with the centering rings this also prevents any canting of the fins along the flight axis.
The wooden beams will be laminated with strips of glass fiber cloth and epoxy to the motortube. All other parts are glued together with epoxy.
The second last ring is only 3 mm thick but has a 1 mm G10 enforcement. It has 4 holes for M4 threaded rods which prolongate through the last centerring ring and are used to connect the thrustplate.
To strengthen the whole fincan it will be filled with 2k PU foam, the centering rings have holes to allow foam to expand through them.
The thrustplate consits of 6 mm G10 with a 2.5 mm deep groove on its outer edge so that it can be plugged inside the bodytube. It is not glued in but hold in place by 4 M4 nuts, which are connected with threaded rods to the second last centering ring. The thrustplate has a 2.5 mm deep cutout for the motortube. It also holds the 75 mm flanged Aeropack retainer which is held in place by 12 M4 screws connected through the thrustplate to KFS2-M4 PEM self clinching nuts. The holes for the M4 screws normally 4.2 mm in diameter have 2.5 mm deep enlargements to 6.4 mm to press-fit the KFS2-M4 PEM nuts. The nuts are pressed in place by a vise, while a installed screw is used for alignment.
The nosecone is unchanged from the rocketry warehouse formula 150 kit.
It consist of filament wound fiberglass with an Aluminum tip and has a Von Karman shape. The nosecone itself is 864 mm long an weights 2025 g. It is connected to the rocket by a 235 mm long coupler tube from which 150 mm protrude into the main body tube. A second ebay carrying a separate tracker for the nosecone is installed in the coupler. The ebay consist of two 3 mm thick G10 rings, which have 1 mm (closer to front) and 1.5 mm grooves aligning them in the coupler. They are connected by 4 M6 threaded steel rods. The ring closer to the front is open to allow the antenna of the tracker to protrude into the nosecone. The bulkhead closing the coupler tube has a M8 U-bolt for attachment of the drogue recovery gear. The electronic bay is 1 mm thick G10 which is connected to the M6 rods trough 15x15x2 mm aluminum angles. The tracker is an Altusmetrum TeleGPS which is hold in place by 4 M3 nylon screws. It is powered by a 1000 mAh 1s Lipo secured with tire warps to the sled. An Altimax MagSwitch is used for switching. The Antenna of the TeleGPS is aligned by a Plexiglas tube. The coupler is glued into the nosecone together with the upper bulkhead. It is further secured by six 3\,mm bolts.