My first build thread!
In my third model rocket lifetime, I started small with this one: the Estes kit of the original Centuri Phoenix Bird, left below. It happened to be on sale at a local store. I built it in a few days and painted it with plastic model paints I had lying around. This was last summer to fly at Bong. FYI, it flies on a B4-4 but is under-powered, C6-5 is much better.
This of course gave me the idea to start scaling it up. At right above, is another of the same kit, Phoenix Bird “E”, with a 24 mm motor mount and a baffle from Apogee. While I was at it, I added a Nomex chute protector to the original. No more wadding! The E flies nicely on a C11-5. While it could take a D, composite E or even F, I don’t think I would ever see it again! At least until Chute Release is available in a mini size :wink:.
As it should, this drove me to go for a 29 mm motor mount for eventual L1. Entering 2017, I started with someone’s RKT file, thanks! I pulled it into OpenRocket and after teaching myself a few things, like defining the motor mount, scaled it up 171%. This was set by the ratio of available body tube diameters: 3.35 mm original to 5.74 mm. After figuring out how to print the plans, including the fin patterns, I set to it.
Step One, Get the Parts:
The two hardest ones were selecting a 57 mm nose cone and fin material. Nose cones are hard to find, unless you are willing to roll your own. I’m not there, yet
. I settled on one from LOC Precision. It was longer than the plans called for so I adjusted the payload bay shorter to keep the overall length at the scaled up value. As to fins, I did some digging around for what materials are appropriate for mid to high power. I settled on 1/8” balsa with a paper skin, more later. The original kit had through the wall fins so I kept those. You might have noticed the tube is slotted. I went ahead and got both the tube and the nose cone direct from LOC Precision, as they sell the body tube slotted for four fins. Again, I’m not there, yet! Everything else is from Apogee, except for the Estes retainer that was from Amazon I think.
Step Two, Cut Tubes:
The motor mount, coupler and body tube were cut to the proper lengths according to my parts listing. I followed Apogee’s “how to” on tube cutting and it worked pretty well.
Step Three, Ejection Baffle:
It is three half-moons made from two bulkheads mounted serpentine inside half a coupler. I had to glue a strip onto the center disk as I could see daylight through it with them installed. Next time, I’ll cut the center one a bit beyond the centerline. Note that I settled on Titebond III Wood Glue (TB3) for all assembly, except as noted. The consensus seems to be that this is the strongest bond with porous materials. I forgot to take a picture of the baffle with the Kevlar harness attachment before I glued it in, so here it is. The picture is a little misleading. The loop is threaded through two 1/16” holes and passes under the first half-moon of the baffle, just behind its “leading” edge. It ends about 1/2 – 1 inch below the tube end.
Step Four, Payload Bay Bulkhead:
I glued the eye bolt into the payload bulkhead. This was done with 60 minute epoxy. The bulkhead insert suggested gluing the threads with epoxy and I wanted the epoxy to penetrate the wood as well. My review of other threads suggested that 5 minutes is not long enough. Here are all the parts so far. The Kevlar thread on the payload side of the eyebolt is for security. I’m going to attach that to the nose cone and tether the altimeter to that. If for some reason the nose cone separates, it should all come down together. Note the extra tube on the nose cone is just to hold it upright and will not be in the rocket. Somewhere in there I filled the seam on the nose cone and sanded smooth.
Step 5, Motor Mount:
Typical stuff here. I used the 29 mm Estes retainer and 60 minute epoxy on the retainer. TB3 everywhere else. In my haste, I glued the retainer and aft centering ring on before installing. In retrospect, I would have left these off to facilitate centering the fins and adding internal fillets. I went ahead and added fillets under the top ring, above the middle ring and below the bottom ring. I wanted to leave as much room as possible for the fin tabs. Fillets are with Titebond Quick & Thick Multi-Surface Glue (TQT). Again, this seems to be penetrating wood glue for strength with porous materials. It is thicker so it resists running while the fillet dries.
Step 6, Fins!
I cut out the fins after aligning the leading edges of the templates with the wood grain. In OpenRocket, I had to adjust the placement of the fin tabs on the main fins in order to fill the space between the centering rings properly. I added tabs to the “fin-let” to fill the slot in the tube completely as well. I cut the fin tabs a little longer than the pattern called for so I could tailor each fin to its final position. At left below are the fins cutout and ready for sanding. I sanded them round on the leading edge, trying to account for the “fin-let” ahead of the main fin. I tapered the trailing edges of the main fins as best I could. At right below are the fins during sanding. At least two of the fins have a divot at the transition to flat but I went with it.
Since papering balsa is not something I had done before, I did some scouring of threads again looking for a way to paper them. I settled on trying a thin layer of glue with freezer paper. I think I wasn’t able to get the glue thin enough as the paper on my test fin pulled into the wood grain. Also, it gapped on the trailing edge as the glue dried. Maybe I could have tried again putting the thin coat of glue on the paper and adding some compressible layers above and below to sandwich the taper but I switched to Avery label paper. This seems to work better, as the thicker paper hides some of the imperfections in the fins and the adhesive is pre-applied. Finished them with several applications of CA on the edges and sanded into shape. I forgot to take a picture of the finished fins but you will get the idea in the next episode.
Happy Flying!
Homer
In my third model rocket lifetime, I started small with this one: the Estes kit of the original Centuri Phoenix Bird, left below. It happened to be on sale at a local store. I built it in a few days and painted it with plastic model paints I had lying around. This was last summer to fly at Bong. FYI, it flies on a B4-4 but is under-powered, C6-5 is much better.
This of course gave me the idea to start scaling it up. At right above, is another of the same kit, Phoenix Bird “E”, with a 24 mm motor mount and a baffle from Apogee. While I was at it, I added a Nomex chute protector to the original. No more wadding! The E flies nicely on a C11-5. While it could take a D, composite E or even F, I don’t think I would ever see it again! At least until Chute Release is available in a mini size :wink:.
As it should, this drove me to go for a 29 mm motor mount for eventual L1. Entering 2017, I started with someone’s RKT file, thanks! I pulled it into OpenRocket and after teaching myself a few things, like defining the motor mount, scaled it up 171%. This was set by the ratio of available body tube diameters: 3.35 mm original to 5.74 mm. After figuring out how to print the plans, including the fin patterns, I set to it.
Step One, Get the Parts:
The two hardest ones were selecting a 57 mm nose cone and fin material. Nose cones are hard to find, unless you are willing to roll your own. I’m not there, yet
. I settled on one from LOC Precision. It was longer than the plans called for so I adjusted the payload bay shorter to keep the overall length at the scaled up value. As to fins, I did some digging around for what materials are appropriate for mid to high power. I settled on 1/8” balsa with a paper skin, more later. The original kit had through the wall fins so I kept those. You might have noticed the tube is slotted. I went ahead and got both the tube and the nose cone direct from LOC Precision, as they sell the body tube slotted for four fins. Again, I’m not there, yet! Everything else is from Apogee, except for the Estes retainer that was from Amazon I think.
Step Two, Cut Tubes:
The motor mount, coupler and body tube were cut to the proper lengths according to my parts listing. I followed Apogee’s “how to” on tube cutting and it worked pretty well.
Step Three, Ejection Baffle:
It is three half-moons made from two bulkheads mounted serpentine inside half a coupler. I had to glue a strip onto the center disk as I could see daylight through it with them installed. Next time, I’ll cut the center one a bit beyond the centerline. Note that I settled on Titebond III Wood Glue (TB3) for all assembly, except as noted. The consensus seems to be that this is the strongest bond with porous materials. I forgot to take a picture of the baffle with the Kevlar harness attachment before I glued it in, so here it is. The picture is a little misleading. The loop is threaded through two 1/16” holes and passes under the first half-moon of the baffle, just behind its “leading” edge. It ends about 1/2 – 1 inch below the tube end.
Step Four, Payload Bay Bulkhead:
I glued the eye bolt into the payload bulkhead. This was done with 60 minute epoxy. The bulkhead insert suggested gluing the threads with epoxy and I wanted the epoxy to penetrate the wood as well. My review of other threads suggested that 5 minutes is not long enough. Here are all the parts so far. The Kevlar thread on the payload side of the eyebolt is for security. I’m going to attach that to the nose cone and tether the altimeter to that. If for some reason the nose cone separates, it should all come down together. Note the extra tube on the nose cone is just to hold it upright and will not be in the rocket. Somewhere in there I filled the seam on the nose cone and sanded smooth.
Step 5, Motor Mount:
Typical stuff here. I used the 29 mm Estes retainer and 60 minute epoxy on the retainer. TB3 everywhere else. In my haste, I glued the retainer and aft centering ring on before installing. In retrospect, I would have left these off to facilitate centering the fins and adding internal fillets. I went ahead and added fillets under the top ring, above the middle ring and below the bottom ring. I wanted to leave as much room as possible for the fin tabs. Fillets are with Titebond Quick & Thick Multi-Surface Glue (TQT). Again, this seems to be penetrating wood glue for strength with porous materials. It is thicker so it resists running while the fillet dries.
Step 6, Fins!
I cut out the fins after aligning the leading edges of the templates with the wood grain. In OpenRocket, I had to adjust the placement of the fin tabs on the main fins in order to fill the space between the centering rings properly. I added tabs to the “fin-let” to fill the slot in the tube completely as well. I cut the fin tabs a little longer than the pattern called for so I could tailor each fin to its final position. At left below are the fins cutout and ready for sanding. I sanded them round on the leading edge, trying to account for the “fin-let” ahead of the main fin. I tapered the trailing edges of the main fins as best I could. At right below are the fins during sanding. At least two of the fins have a divot at the transition to flat but I went with it.
Since papering balsa is not something I had done before, I did some scouring of threads again looking for a way to paper them. I settled on trying a thin layer of glue with freezer paper. I think I wasn’t able to get the glue thin enough as the paper on my test fin pulled into the wood grain. Also, it gapped on the trailing edge as the glue dried. Maybe I could have tried again putting the thin coat of glue on the paper and adding some compressible layers above and below to sandwich the taper but I switched to Avery label paper. This seems to work better, as the thicker paper hides some of the imperfections in the fins and the adhesive is pre-applied. Finished them with several applications of CA on the edges and sanded into shape. I forgot to take a picture of the finished fins but you will get the idea in the next episode.
Happy Flying!
Homer
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