lalligood
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A full review for EMRR is in the works but I thought I'd give an early preview here (especially since it'll be 2 or 3 more weeks before I get to fly it!)
I started working on the second of 3 USR kits that I received in the past week or so. The Weightlofter is a fairly challenging to build mid power 7-motor cluster rocket that is similar to the USR AeroRoc. It has a central 29mm MMT surrounded by 6 24mm motor tubes that actually are about halfway exposed outside the the 2.25" main airframe tubing. It can fly on one central motor (required for chute ejection), or with 2, 3, 4, or 6 outboards. There is a 24mm motor adapter included if you want to use all 24mm motors too. The root edge of the fins mount into the wedge of a pair of motor tubes (like the Loc Viper & TriStar) as well as flat against the main airframe near the leading edge. This robust motor configuration and fin attachment gives the Weightlofter an aggressive look. Nose weight is required for most clustered flights.
I used yellow wood glue (aliphatic resin) exclusively for the build. Yellow wood glue is still stronger than the wood and/or cardboard materials themselves but doesn't have the weight penalty of epoxy.
The build starts with building the motor mount. There are 2 centering rings that are glued near one end of the 29mm tube. The main airframe tube is marked for fin alignment and then the MMT tube is glued with about half of the 29mm tube exposed out the eft end. Then the 24mm motor tubes are grouped and glued into pairs. Once dry, all 3 pairs of tubes are glued onto the 29mm tube with the crease of the tubes lined up with the marks on the large airframe tube. Let everything dry.
The fins are laser cut 1/8" birch ply. They are mounted into the valley of the 24mm tubes and the root edge is so long that it lays along the 2.25" airfram too. In order to get them flush with both surfaces, I used my Dremel with a sanding drum to shape the aft 3" of the root edge into a V shape. Fins were then attached one at a time and allowed to dry before attaching the next one. Fillets were done equally as patiently.
Because the motor tubes extend so far outside the main airframe, I decided to use the included launch lugs instead of my personal preference of rail buttons. I guess I could've used rail buttons but I would have had to build some pretty high standoffs.
The rest of the rocket was fairly routine: put screw eye in bulkhead, glue bulkhead in coupler, glue coupler in payload tube. Hard balsa nose cone (typical in USR kits) is left to friction fit so that nose weight can be added when needed.
Recovery is a long piece of 1/4" elastic attached to the screw eye in the payload and the tried-and-true 3-fold attachment inside the body tube. Surprisingly (at least based off of other USR reviews on EMRR), the chute was a 16" mylar--instead of a supposed paper--chute with Kevlar lines and a snap swivel! This might be a little on the small side for clustered flights and/or if landing on hard surfaces is likely, but I've got a spare 18" nylon chute in my range box if I ever want to swap it out for something a little bigger... Instructions are also included with the chute on making/using a metal or tape ring to aid in a more gentle chute deployment. I was able to make one out of 2 pieces of masking tape with the adhesive turned against each other.
Construction complete. Now on to the finishing.
The balsa nose cone was coated with finishing epoxy & the fins and nose cone were smeared with diluted Elmer's Fill 'n' Finish and then sanded with 320 grit. Primer & paint are in the near future... Paint scheme is probably going to be orange and red to match (at least colorwise) with my beloved Banshee.
That's about it for now. Pics to follow...
I started working on the second of 3 USR kits that I received in the past week or so. The Weightlofter is a fairly challenging to build mid power 7-motor cluster rocket that is similar to the USR AeroRoc. It has a central 29mm MMT surrounded by 6 24mm motor tubes that actually are about halfway exposed outside the the 2.25" main airframe tubing. It can fly on one central motor (required for chute ejection), or with 2, 3, 4, or 6 outboards. There is a 24mm motor adapter included if you want to use all 24mm motors too. The root edge of the fins mount into the wedge of a pair of motor tubes (like the Loc Viper & TriStar) as well as flat against the main airframe near the leading edge. This robust motor configuration and fin attachment gives the Weightlofter an aggressive look. Nose weight is required for most clustered flights.
I used yellow wood glue (aliphatic resin) exclusively for the build. Yellow wood glue is still stronger than the wood and/or cardboard materials themselves but doesn't have the weight penalty of epoxy.
The build starts with building the motor mount. There are 2 centering rings that are glued near one end of the 29mm tube. The main airframe tube is marked for fin alignment and then the MMT tube is glued with about half of the 29mm tube exposed out the eft end. Then the 24mm motor tubes are grouped and glued into pairs. Once dry, all 3 pairs of tubes are glued onto the 29mm tube with the crease of the tubes lined up with the marks on the large airframe tube. Let everything dry.
The fins are laser cut 1/8" birch ply. They are mounted into the valley of the 24mm tubes and the root edge is so long that it lays along the 2.25" airfram too. In order to get them flush with both surfaces, I used my Dremel with a sanding drum to shape the aft 3" of the root edge into a V shape. Fins were then attached one at a time and allowed to dry before attaching the next one. Fillets were done equally as patiently.
Because the motor tubes extend so far outside the main airframe, I decided to use the included launch lugs instead of my personal preference of rail buttons. I guess I could've used rail buttons but I would have had to build some pretty high standoffs.
The rest of the rocket was fairly routine: put screw eye in bulkhead, glue bulkhead in coupler, glue coupler in payload tube. Hard balsa nose cone (typical in USR kits) is left to friction fit so that nose weight can be added when needed.
Recovery is a long piece of 1/4" elastic attached to the screw eye in the payload and the tried-and-true 3-fold attachment inside the body tube. Surprisingly (at least based off of other USR reviews on EMRR), the chute was a 16" mylar--instead of a supposed paper--chute with Kevlar lines and a snap swivel! This might be a little on the small side for clustered flights and/or if landing on hard surfaces is likely, but I've got a spare 18" nylon chute in my range box if I ever want to swap it out for something a little bigger... Instructions are also included with the chute on making/using a metal or tape ring to aid in a more gentle chute deployment. I was able to make one out of 2 pieces of masking tape with the adhesive turned against each other.
Construction complete. Now on to the finishing.
The balsa nose cone was coated with finishing epoxy & the fins and nose cone were smeared with diluted Elmer's Fill 'n' Finish and then sanded with 320 grit. Primer & paint are in the near future... Paint scheme is probably going to be orange and red to match (at least colorwise) with my beloved Banshee.
That's about it for now. Pics to follow...