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  #31  
Old 11-11-2020, 02:03 PM
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georgegassaway georgegassaway is offline
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When I have had stages that plug in, then whenever practical I have added a thrust ring at the BOTTOM of the booster engine mount tube (would have to make a longer tube to allow for that ring if it's a kit). That way, the booster engine can never blow out the back. I think some old Centuri staged kits did that.

But I have also done models where the booster tube was the same diameter as the motor that fit in it. For those, I did not have the booster slide up over the tape holding the two motors together, the booster either used friction-fit of tape, or else I literally added some tape wrapped around the top of the booster tube and top of the booster motor (say a 1/4 to 1/2" gap from top of booster tube to top of booster motor, and the booster fin root did not run all the way to the top of the booster tube).

On REALLY stable models, no booster airframe at all, "CHAD" staging with just the booster motor taped to the upper motor.
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  #32  
Old 11-11-2020, 02:16 PM
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Quote:
Originally Posted by georgegassaway
On REALLY stable models, no booster airframe at all, "CHAD" staging with just the booster motor taped to the upper motor.

I used to CHAD stage D12's to C6-7's on one of my old Big Berthas back when I flew on a large field. I just slipped the D12 over the C6 casing and let it sit flush against the rear of the model, no tape needed.

Sometimes I had to trim some bulging off the end of the C6 so the D12 wouldn't fit too tight. I didn't even remove the engine hook. I pulled it out enough to let the D12 slide under. When it staged, the D12 kicked away and the hook latched to the C6 to hold it in for ejection.
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  #33  
Old 11-13-2020, 11:41 AM
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Quote:
Originally Posted by Green Dragon
the old Centuri kits actually had an engine block at REAR of the booster, to prevent that from happening, good idea.

generally speaking, on Estes kits, like the old Vigilante we flew Sat, the booster engine will stick past the motor tube and then you wrap tape around the exterior joint at rear of booster.
At least some of Estes' earlier kits (the minimum-diameter [BT-20] Apogee II http://www.spacemodeling.org/jimz/estes/k-05.pdf was an example--it may have been their very first two-stage kit) also used the rear engine block in the first stage body tube. A later, BT-50 size two-stage kit of theirs, the Shrike (see: http://www.spacemodeling.org/jimz/estes/estk-46.pdf ) , used what they called "plug-and-go" staging; both stages had normal engine mounts with motor clips, but the instructions said to wrap enough masking tape around both engines to create gas-tight seals. Apparently this was to ensure that the stages would separate rapidly, to avoid second-stage blast damage to the first stage--the gas from the second stage motor, expanding to fill the interior volume, "popped" the stages apart.
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  #34  
Old 11-13-2020, 12:50 PM
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Quote:
Originally Posted by georgegassaway
When I have had stages that plug in, then whenever practical I have added a thrust ring at the BOTTOM of the booster engine mount tube (would have to make a longer tube to allow for that ring if it's a kit). That way, the booster engine can never blow out the back. I think some old Centuri staged kits did that.

But I have also done models where the booster tube was the same diameter as the motor that fit in it. For those, I did not have the booster slide up over the tape holding the two motors together, the booster either used friction-fit of tape, or else I literally added some tape wrapped around the top of the booster tube and top of the booster motor (say a 1/4 to 1/2" gap from top of booster tube to top of booster motor, and the booster fin root did not run all the way to the top of the booster tube).

On REALLY stable models, no booster airframe at all, "CHAD" staging with just the booster motor taped to the upper motor.
The British Skylark 7 sounding rocket (a Raven motor boosted by a Goldfinch motor: http://news.bbc.co.uk/2/hi/science/nature/4490253.stm ) and the three-stage Skylark 12 (Goldfinch + Raven + Cuckoo: http://www.astronautix.com/s/skylark.html ) used full-scale CHAD staging (and optional Imp spin motors ignited at launch, for use at ranges such as Sweden's Esrange https://www.sscspace.com/ssc-worldw...e-space-center/ , which have small downrange impact areas). Scale models of these Skylark variants fly equally well.
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  #35  
Old 11-13-2020, 01:25 PM
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Quote:
Originally Posted by blackshire
The British Skylark 7 sounding rocket (a Raven motor boosted by a Goldfinch motor: http://news.bbc.co.uk/2/hi/science/nature/4490253.stm ) and the three-stage Skylark 12 (Goldfinch + Raven + Cuckoo: http://www.astronautix.com/s/skylark.html ) used full-scale CHAD staging (and optional Imp spin motors ignited at launch, for use at ranges such as Sweden's Esrange https://www.sscspace.com/ssc-worldw...e-space-center/ , which have small downrange impact areas). Scale models of these Skylark variants fly equally well.

The Iris looked like a chad stag. IIRC, it's finless booster burned out about the time it left its launch tower, so from a model rocketeer's perspective, I wouldn't count it. The Skylark is a true chad stage...is this life imitating art? I don't think it had a booster until 1960. I'm betting modelers chad staged before that.
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  #36  
Old 11-13-2020, 01:52 PM
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Quote:
Originally Posted by tbzep
The Iris looked like a chad stag. IIRC, it's finless booster burned out about the time it left its launch tower, so from a model rocketeer's perspective, I wouldn't count it. The Skylark is a true chad stage...is this life imitating art? I don't think it had a booster until 1960. I'm betting modelers chad staged before that.
*Nods* Yes, ARC didn't include fins on the seven-motor (six in a hexagonal cluster, with the seventh in the center) booster because it ceased to push against the Iris before it left the three-fin (at Eglin AFB) or four-fin (at Wallops) Aerobee tower; the triple-Sparrow Hydra-Iris boosters had fins because the booster and the Iris flew together under thrust for a few seconds after sea launch, and:

You're right--the Cuckoo motor (which was considerably shorter than the later Goldfinch; when used as a booster for Skylark vehicles, it was fitted with small fins: https://space.skyrocket.de/doc_lau/skylark_cuckoo.htm [a finless, spin-stabilized Cuckoo IV served as the Skylark 12's third stage]) was adopted as the first Skylark booster in 1960: http://www.sat-net.com/serra/skylar_e.htm . The Cuckoo was also used as the upper stage--mounted upside-down--on some Black Knight vehicles, firing downward to push test re-entry bodies into the atmosphere at high velocity over the Woomera range (the three-stage, Redstone-based SPARTA vehicles--the last of which orbited WRESAT, Australia's first satellite, in 1967--continued the re-entry test work).
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  #37  
Old 11-13-2020, 02:09 PM
shockwaveriderz shockwaveriderz is offline
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