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Phoenix Bird Series - My Journey to L1

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Homer_S

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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.

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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.

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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.

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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.

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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.

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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.

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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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Homer_S

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Step 7, Final Assembly:
I assembled the payload bay by gluing the bulkhead flush with the end of the coupler and with a fillet on the inside, then half of the coupler length into the payload tube. I gave the shoulder area a sand to ensure an easy release from the airframe. After dry fitting the motor mount and fins to ensure they end flush with the body tube, I marked the location of the visible centering rings. Gluing the motor mount in was by putting a coat of TB3 on the three rings and running it up into place. I then withdrew it and put a second coat on the rings and back in place. Once that had setup, I went through the fin slots with a generous amount of TB3 to create “fillets” as best I could. Finally, I finished with a fillet of the TQT above the top centering ring. I was able to get a long stick in there to get the fillet into shape.

I added the fins next so I could work with a shorter tube while aligning them. I dry fit each and cut the tab to make the fins fit snugly to the motor mount and body tube. I used the same ”glue, remove, recoat and final position” approach. I started with the main fins in opposing pairs. After the first pair setup some, I added the second pair and blocked them all square. Once that was dry, I positioned the “fin-lets” and smoothed them into the main fin using some of the JB3.

Next up, I glued in the coupler with the Kevlar up and finally the top part. I aligned the spirals between the two halves, you know, because. Here are the subassemblies ready for paint preparation, below left. Again, the payload bay has an extra piece just to hold it upright.

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Step 8, Paint Prep:
Here is where I really have to resist my urge to go fly. Imperfections always show through the paint so I tried to slow down. I started with filling the body tube spirals using Elmer’s Wood Filler, thinned with 90% iso-propanol so that it spreads but stays put. Water tends to warp things before it evaporates so using the IPA reduces that. Also, you can proceed to the sanding and second layers as the IPA evaporates more quickly. Working in short sections, I spread the filler into the spirals and then scraped across them with a balsa scrap to reduce later sanding. Here is a picture between applications, above right.

After a second coat of wood filler and sanding to touch up the main ones and fill the secondary ones, I marked the tube and glued on the 1/4” launch lug. I split it in half and put one piece at the bottom of the body tube and one flush with the top end of the fin can. This is to mimic the parts from the original, which had two lugs. I’m planning to add conformal rail guides in the next space between fins as well for high power. Do you think they are overkill?

Once the lugs were dry it was time to fillet the fins facing up. Once those are dry, rotate 90 degrees and repeat until all are filleted. I applied fillets to the launch lugs as those joints faced up.

Final prep before priming is to touch up the fins where anything came loose or got dinged during assembly. So I have more CA and sanding to do tonight.
This is where I am. Next up will be painting and scaling up the original kit’s decals which are red on silver Mylar.

Happy Flying!
Homer
 
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Homer_S

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Steps 9 and 10: Final Finish:
Just for completeness, here are the painted and final images. I forgot to take a picture primed, just imagine the painted picture as one grey color.

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If I remember, I'll update with a flight pic.

Homer
 

K'Tesh

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I'm liking what I see so far... I'm in! :pop:
 

Homer_S

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First flight!

Super sunny Saturday, almost no wind. Lots of straight up and straight down flights. Here are the pictures on an AeroTech F23FJ-4.

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It was carrying both a Jolly Logic AltimeterThree and Jolly Logic Chute Release. Flight was up to 481 feet with ejection at 480 feet on the way down. Initial descent was 41 fps (28 mph) and 13 fps (9 mph) at landing. Chute Release was set at 200 feet and it looks like full deployment was at about 100 feet. Made for an exciting flight without much chasing. The rocket was recovered maybe 10 feet into the brush, just south off the runway. I was quite pleased!

Now to plug all this into OpenRocket and see if I can improve on my estimated altitude for the L1 flight next month (fingers crossed). The estimate for this flight was 30% higher. I'm thinking some underestimated weights and perhaps too optimistic on surface finish.

UPDATE: I looked at the thrust curve in OpenRocket v. the data from NAR. I created an ENG file from the data and after changing the ID line to "F23FJa", relaunching OR, selecting the new thrust curve and rerunning the sim things are much better. Predicted is 492 feet and actual was 481 feet or 98% agreement. Not too shabby. This is with using Regular Paint finish, rounded fins and some weights not quite exact.

Homer
 

Homer_S

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Journey hit a speed bump. Launched it on October 1, went straight up into a cloud and hasn't been seen again. I think I did not wrap the Chute Release tight enough and it opened at apogee (~2400').

Homer
 

Homer_S

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Updated update: the rocket was recovered only about 100 yards from the launch pads. The Chute Release had not opened. I'm thinking either it timed out before launch or I managed to turn it off before launch. Another flyer found the rocket and I'm getting it back on Saturday with dinged fins and a stick stuck through it.

Homer
 

rharshberger

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Updated update: the rocket was recovered only about 100 yards from the launch pads. The Chute Release had not opened. I'm thinking either it timed out before launch or I managed to turn it off before launch. Another flyer found the rocket and I'm getting it back on Saturday with dinged fins and a stick stuck through it.

Homer
AFAIK, once turned on JLCR's dont turn off until the battery dies. I have had one sit on the pad for over an hour without issue.
 

Homer_S

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Must have been me turning it off then. Is it possible that the pressure of putting the nose cone on confused the pressure sensor?

Homer
 

Flyfalcons

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I have seen them open when pulling a tight nose cone off and putting it on, but not turn off.
 

afadeev

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Must have been me turning it off then. Is it possible that the pressure of putting the nose cone on confused the pressure sensor?
No.
Read below.


I have seen them open when pulling a tight nose cone off and putting it on, but not turn off.
No to argue, but that seams highly unlikely.

JL CR is not active until it detects flight, or pressure decrease commensurate with altitude of 100+feet (relative to altitude sampled at startup) for 3+ continuous seconds. Pulling tight nose cone for 3+ seconds is not impossible, but requires one hell of a long nose cone shoulder!

More info here:
https://www.jollylogic.com/wp-content/uploads/2015/12/JollyLogicChuteReleaseWeb.pdf

a
 

Homer_S

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I got the rocket back today, thanks Paul!

The Altimeter Three reported a max speed of 491 mph with max acceleration of 20.5G. Ejection was early at 2990' and coasted 1.9 sec to apogee at 3032'. [EDIT: predicted was 2408'... guess is the motor is hotter than the ENG file in OpenRocket.] Optimum delay was 9 sec and was drilled to about 8 sec. It proceeded to fall at 50 fps until striking the ground after 76 seconds of total flight. It continued to record for a total of about four hours ten minutes. At that point it recorded landing at 6 fps.

Based on the pictures below, it looks like the initial impact was with a branch that pierced a fin close to its trailing edge and then fell to its final spot. Either that or just noise. Also, the Chute Release did not release. It is still functional and fully charged. I tested it when I got home. It behaved normally and was still set to 200'.

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Homer
 

Homer_S

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This was an Aerotech H115DM for an L1 attempt.

It would be flyable without repair. I'll fill and finish the two dinged/skewered fins though.

Homer
 

afadeev

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Also, the Chute Release did not release. It is still functional and fully charged. I tested it when I got home. It behaved normally and was still set to 200'.
Now THAT is interesting.
I haven't had any CR malfunctions yet, and failure to release would make for a bad day with most of my nicer rockets. Would definitely like to understand this scenario better.

Did you power cycle/turn-ON the CR right in the launch area, or somewhere else when you were assembling the rocket and packing the chute?
Did you test release it before the flight?
Does it test release now?

a
 

Glasspack

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Very happy you got your model back....... Sorry you didnt get the CERT. Same exact thing happened to my son and his V2 that Saturday........ I know I would want someone to try to find me, if it were my rocket that was found.
Now I have to get id information my models. Thank you Robert again for the card. That was not neccessary but was very apprecciated. I will..... "fly one on you"

Paul
 

Homer_S

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Now THAT is interesting.
I haven't had any CR malfunctions yet, and failure to release would make for a bad day with most of my nicer rockets. Would definitely like to understand this scenario better.

Did you power cycle/turn-ON the CR right in the launch area, or somewhere else when you were assembling the rocket and packing the chute?
Did you test release it before the flight?
Does it test release now?

a
Yes, I had to turn it on. It did release when I tested it. I think there are two take homes.

1 - Put the nose cone on and don't dink with it.
2 - Leave enough room in the parachute section for the whole load of laundry. When assembled there is a 1/8" gap as there is not quite enough room for the packed chute.

It flew fine with an F motor, see above. It just looks dodgey.

Homer
 

Lowpuller

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You just explained your problem........you said I turned the Chute Release on when I tested it..........hence the great "catch 22" of the Chute Release it automatically powers down after the test and you have to turn it back on! Don't ask me how I know...........

Based on the damage being minimal to none, my guess, everything worked as designed and luckily the drag slowed you down enough to prevent damage.

Try again, use a baby H, turn CR back on after test..........your L1
 

Homer_S

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You just explained your problem........you said I turned the Chute Release on when I tested it..........hence the great "catch 22" of the Chute Release it automatically powers down after the test and you have to turn it back on! Don't ask me how I know...........

Based on the damage being minimal to none, my guess, everything worked as designed and luckily the drag slowed you down enough to prevent damage.

Try again, use a baby H, turn CR back on after test..........your L1
+1

I wonder if this can get added to the manual or their FAQ?

Mystery Solved!
Homer
 

John Beans

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There are trade-offs. Here are my thoughts.

If we changed the operating scheme so that it stayed on after ground test:

1. You'd have to remember to turn it off after flying
2. We'd have to continuously sense ground elevation, rather than sampling once at turn on
3. To avoid a falsely high or low ground sample in the fuselage, venting would not only be required, you'd have to have GOOD venting
4. Failure to vent well and/or suction during loading from pistoning the nosecone would greatly increase the chance of a "false launch" (it's rare currently) or a faulty ground level
5. Accurate continuous ground sampling and immediate launch detection would require significantly higher power consumption, so the battery life would drop substantially

The ability to fly Chute Release most of the time without venting and long battery life between charges are a nice benefits of the current scheme.
 

Homer_S

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Agree with all your trade-offs and your decision on the current behavior. I see in the manual it does say remember to turn it on (missed that one :blush:). Could it also note that it turns off after ground test? At least give the next round of new buyers learning from Lowpuller's and my mistakes.

Thanks!
Homer

P.S. When will the smaller format version be coming? Hint Hint
 

Glasspack

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Robert,

Thank You for bringing this to light........... I don't think I knew it would power off after test.......
I am going to test & play with my Chute Release this morning.

Still think that Jolly Logic device is one of THE COOLEST rocketry devices in Many, Many years

Paul
 

Homer_S

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Post mortem... I tried again in April. It came down in two pieces. I overcooked the ejection charge and blew out the baffle. This broke the shock cord mount and caused the payload bay to come loose. Both halves were recovered, thanks to an eagle eyes spotter!, but the rocket is mostly lost. I'll have to rebuild the back half as it looks like a blown up shotgun barrel.

I built another model and ... see here for details.

P.S. Upon close inspection, the baffle wasn't complete blown out. Just enough to shear the Kevlar loop where the shock cord was anchored. I'm debating how best to repair it. Either sand the baffle coupler down so a new tube can be bonded or cut it out completely and go baffle-less. Either way, I'll have to anchor a new shock cord mount. I like the metal loop in the NCR kits, so leaning that way.

Homer
 
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