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Flight of the Phantom
I have an original Estes Phantom I built in the 70s, so when the new one came out I thought it would be fun to fly it to see what happens. I looked up threads on clear rockets and they have been done before. One guy used a clear sleeve in the parachute compartment to keep the ejection charge from damaging the tube. He said he used polycarbonate or polypropylene sheet to make a liner. I don’t know what either of those are, so I went hunting for a sheet protector or report cover, but ended up only finding a clear notebook sleeve. The mods I made to the kit were:
1) Tied Kevlar to the engine hook, Semroc style. This also lifts the hook up enough that a Q-jet charge well fits under the hook. I cut two channels in the forward centering ring, outside edge, to pass the loop of Kevlar through. I tied the kit shock cord to the other end of the Kevlar. 2) Installed a 3/8” long engine block cut from a used casing. The main reason for this is to prevent ejection from melting the motor tube. I retrofit it from the forward end because I forgot during construction. 3) Straightened a fin. One of the fins was curled, it was cupped so it would have grabbed a lot of air. I boiled a pot of water and put the fin in for two seconds, and it became pliable and I was able to straighten it. The last picture shows the sleeve before being fully seated. |
#2
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I though based on the weight that a B4-4 qjet would be a good flight, and the orange label would look great in the mount. The other thing is the ejection is all powder, not clay and powder, and the charge well extends all the way to the end of the motor tube so less worries about melting the motor tube. The wide were predicted to be 4mph this morning, so it seemed like a good day to try it. At the park they seemed higher, but were blowing in a good direction. The Phantom zipped away with authority perfectly straight. At burnout it just...disappeared. I searched the sky and saw a flash that was probably the ejection, but nothing immediately after that. I had that ‘I’ll need another Phantom feeling’ but keet looking and looking down the field. Finally I spotted it way downrange about 100 feet above the ground and saw it touchdown more than 200 yards away. Here is the launch: LAUNCH I went to retrieve it and when I got there it looked good. The tube was dirty, the sleeve had ejected and was hanging on the shock cord, but it looked good overall. I immediately tried to remove the motor to prevent it from fusing to the tube. It did resist, but I was able to twist it free. The problem was a small section of the label surface stuck in the tube. I brought it home and was able to clean the main tube, but it’s discolored some right above the engine mount. Interestingly, there is ejection residue in the very tip of the nosecone, which is surprising. The chute had only a dime size discoloration, it can easily be flown again.
Last edited by 5x7 : 07-30-2020 at 06:38 PM. |
#3
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You now have a rocket bong.
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I love sanding. |
#4
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That actually looks a bit cleaner than I might have thought.
I have done some nighttime videotaping of ejection charges back in the late 80s when I was working on converting an Estes Space Shuttle kit to have ejectable SRBs. I had the ET locked down and did simultaneous ignition tests with Mini A motors in the SRBs to see how well they separated from the ET. I was gonna use an Aerotech D8 for the main motor. In any event, the SRBs ejected well with the fastening system to the ET, but I never did finish up that project to flight status (entry into HPR about that time kinda got in the way). BUT, the tests did reveal one thing to me: the ‘fireball’ that came out of the top of each SRB at ejection was ENORMOUS in dark conditions! I was amazed at just how much of ‘flaming ball of fire’ event that an ejection charge firing actually was. And that was from Mini-A motors. The flame front was probably over a foot long out from the top end of each SRB and lots of flaming, burning particles. Earl
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Earl L. Cagle, Jr. NAR# 29523 TRA# 962 SAM# 73 Owner/Producer Point 39 Productions Rocket-Brained Since 1970 Last edited by Earl : 07-30-2020 at 08:08 PM. Reason: Spellin’ fix |
#5
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Cool story, ironically I saw the ejection flash on this flight and I can't ever remember seeing one during the day. It's the bright spot in the second picture in post 2. Maybe it's because of the clear tube. |
#6
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Pretty cool - thanks for posting link to video.
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#7
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#8
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You bet, it really shows how it just winked out of existence. |
#9
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Two things:
1. Estes mini motors (some of them, anyway) have ENORMOUS ejection charges for their size. 2. Where's GH? He has posted several times that he was going to fly the rereleased Phantom. You beat him to it!
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Bernard Cawley NAR 89040 L1 - Life Member SAM 0061 AMA 42160 KG7AIE |
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