stealth6
insert witty tagline here
Latest off the line - my take on a carbon Lil' Rascal. Yes, this was one of those Black Friday specials. I reshaped the fins a bit (but you already knew I was going to do that didn't you?), added a simple nose-cone-based "av bay" so that it could fly dual deploy (using a Cable Cutter), partial paint using Dupli-Color Mirage, and finished off with an Aeropac retainer.
A few notes:
First, some of you were wondering about exactly what was carbon fibre on this kit. It's just the airframe, but it's a very sweet one at that. Seems quite a bit lighter than a similar fibreglass one, and it's very rigid.
The glass nose cone is not filament wound, but rather it's "old school" molded with a gel coat. Which is fine, but do know that that nice glossy black finish is going to get very scuffed up once you do all the normal fitting that is necessary with this type of cone. By that I mean that there is a very large seam that needs to be flattened, and the shoulder needed quite a bit of work to fit right. All this means that you will likely still be painting this cone in the end, so the fact that it's black really has no bearing on things - it could be any color to start with. Also remember that fitting anything internal (such as an AV bay or any type of bulk plates) requires a fair bit more work than with filament wound cones. It might sound like I'm complaining but I assure you I'm not - this is a sweet kit that I'm very pleased with. I'm just pointing out some of the things that folks might not assume at first about the nature of these sorts of components.
I used ProLine epoxy for the fillets. More for the fact that I can get very nice even, smooth, fillets with this material which I wanted knowing that I was going to be painting them the way I did. The fin can is both internally filleted and foamed so I'm pretty confident this rocket can take some hard landings ( a fact of life in these parts).
The AV bay - for whatever reason I decided to mount everything on a single plate. It's a pretty standard construction otherwise, and uses the new RRC-2 for avionics, no charge wells, and with the intention of utilizing a Cable Cutter for mains deployment. The photos are shown actually during the construction process rather than the finished product.
The paint. Ah yes, the paint. This is the first time I've attempted the Dupli-Color Mirage, and I'm pleased with the results. But this stuff is weird. First off, know that it's a FOUR layer process - you need a good primer first, then you apply a black "base coat", then the color layer, and finally a clear coat. It's lacquer so it's a bit different than the enamels that most of us use most of the time. The primer and base coat are standard enough. But the color coat goes on very odd. At first I thought the nozzle was bad as it sprayed out VERY blotchy - not a fine atomized spray at all. If you try this stuff don't panic when you first spray it and it comes out in big wet spurts - it does seem to end up leveling out just fine in the end. But DO make sure you do 5 or more thin coats (I did 8). Finally the clear coat comes out very thick and heavy. Again it was scary at first but it did not end up dripping and it did end up making a very nice gloss coat. Also this stuff is pretty expensive.
I chose the "gold-magenta" color, which is quite difficult to find as it turns out. The detail photos of the nose cone show the different color shifts. I also painted the aft bulk plate just for style points. Oh, and I got a nice gloss on the airframe by wiping it with laminating epoxy thinned with a bit of alcohol.
Nose weight - always a big question with short squats like this. I designed this with the principals outlined here: https://www.apogeerockets.com/education/downloads/Newsletter154.pdf - (thanks for the tip to David Stribling). With these factors in mind, and with the hardware and avionics I've got in there (including a BRB-900 tracker), I only needed to add about 60g of extra nose weight. This gave me a stability factor of 1.07 with the largest motor I will likely fly in this (a J800). In the past I've always erred on the side of too much weight in the cone for short fatties, so we'll see how this goes this time. In all my calculations and in checking in with others, I feel pretty confident this will be stable. The proof will be on that first launch day I guess. Heads Up flight!!
The practical motor range on this rocket is sort of narrow, as it needs something big enough to get it off the pad safely (due to the size/weight/drag), but small enough that it can physically fit. You CAN fit bigger motors (that would extend up into the nose cone) if you build it with this in mind, but I chose not to. As it stands I can fly between a mid sized I to around 3000' and a decent sized J to around 8000', which sounds great to me. This in theory of course as I've yet to fly it. Hopefully I'll get a chance to put it into the sky this winter, but it may wait until spring. I won't be flying any of those J's until I get my Level 2 anyway.
I know what you are saying - "All that's well and good, now shut up and SHOW US SOME PICS!"
OK fine, here you go. Hope you enjoy:
thanks for watching, s6
A few notes:
First, some of you were wondering about exactly what was carbon fibre on this kit. It's just the airframe, but it's a very sweet one at that. Seems quite a bit lighter than a similar fibreglass one, and it's very rigid.
The glass nose cone is not filament wound, but rather it's "old school" molded with a gel coat. Which is fine, but do know that that nice glossy black finish is going to get very scuffed up once you do all the normal fitting that is necessary with this type of cone. By that I mean that there is a very large seam that needs to be flattened, and the shoulder needed quite a bit of work to fit right. All this means that you will likely still be painting this cone in the end, so the fact that it's black really has no bearing on things - it could be any color to start with. Also remember that fitting anything internal (such as an AV bay or any type of bulk plates) requires a fair bit more work than with filament wound cones. It might sound like I'm complaining but I assure you I'm not - this is a sweet kit that I'm very pleased with. I'm just pointing out some of the things that folks might not assume at first about the nature of these sorts of components.
I used ProLine epoxy for the fillets. More for the fact that I can get very nice even, smooth, fillets with this material which I wanted knowing that I was going to be painting them the way I did. The fin can is both internally filleted and foamed so I'm pretty confident this rocket can take some hard landings ( a fact of life in these parts).
The AV bay - for whatever reason I decided to mount everything on a single plate. It's a pretty standard construction otherwise, and uses the new RRC-2 for avionics, no charge wells, and with the intention of utilizing a Cable Cutter for mains deployment. The photos are shown actually during the construction process rather than the finished product.
The paint. Ah yes, the paint. This is the first time I've attempted the Dupli-Color Mirage, and I'm pleased with the results. But this stuff is weird. First off, know that it's a FOUR layer process - you need a good primer first, then you apply a black "base coat", then the color layer, and finally a clear coat. It's lacquer so it's a bit different than the enamels that most of us use most of the time. The primer and base coat are standard enough. But the color coat goes on very odd. At first I thought the nozzle was bad as it sprayed out VERY blotchy - not a fine atomized spray at all. If you try this stuff don't panic when you first spray it and it comes out in big wet spurts - it does seem to end up leveling out just fine in the end. But DO make sure you do 5 or more thin coats (I did 8). Finally the clear coat comes out very thick and heavy. Again it was scary at first but it did not end up dripping and it did end up making a very nice gloss coat. Also this stuff is pretty expensive.
I chose the "gold-magenta" color, which is quite difficult to find as it turns out. The detail photos of the nose cone show the different color shifts. I also painted the aft bulk plate just for style points. Oh, and I got a nice gloss on the airframe by wiping it with laminating epoxy thinned with a bit of alcohol.
Nose weight - always a big question with short squats like this. I designed this with the principals outlined here: https://www.apogeerockets.com/education/downloads/Newsletter154.pdf - (thanks for the tip to David Stribling). With these factors in mind, and with the hardware and avionics I've got in there (including a BRB-900 tracker), I only needed to add about 60g of extra nose weight. This gave me a stability factor of 1.07 with the largest motor I will likely fly in this (a J800). In the past I've always erred on the side of too much weight in the cone for short fatties, so we'll see how this goes this time. In all my calculations and in checking in with others, I feel pretty confident this will be stable. The proof will be on that first launch day I guess. Heads Up flight!!
The practical motor range on this rocket is sort of narrow, as it needs something big enough to get it off the pad safely (due to the size/weight/drag), but small enough that it can physically fit. You CAN fit bigger motors (that would extend up into the nose cone) if you build it with this in mind, but I chose not to. As it stands I can fly between a mid sized I to around 3000' and a decent sized J to around 8000', which sounds great to me. This in theory of course as I've yet to fly it. Hopefully I'll get a chance to put it into the sky this winter, but it may wait until spring. I won't be flying any of those J's until I get my Level 2 anyway.
I know what you are saying - "All that's well and good, now shut up and SHOW US SOME PICS!"
OK fine, here you go. Hope you enjoy:
thanks for watching, s6
