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  #11  
Old 02-06-2020, 07:41 PM
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LeeR LeeR is offline
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Be careful with Estes designations. The average thrust of an A8-3 is not 8 N, its listed as 3.18 N on the NAR thrust curve. But ... it has a pretty healthy peak thrust, and 3 will give a good kick.

http://nar.org/SandT/pdf/Estes/A8.pdf

Some motors are pretty accurately described, like the C11. Itís average thrust is 10.86 N. (A bit more than the D12 average of 10.21 N.)

http://www.nar.org/SandT/pdf/Estes/C11.pdf

http://www.nar.org/SandT/pdf/Estes/D12.pdf

The biggest surprise for me were the designations on the Aerotech D13 and D24 reloads for the 18/20 RMS. The curves are very similar, and the designations should be D13 and D15. Iíve used the D13 in my Mars Lander. I thought the D24 would be overkill. Iíll try them next, and expect little difference.
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Projects: Super Sky Hook, Super X-Ray, Estes Phoenix, Big Daddy, QCC Explorer
Awaiting Paint: Estes Saturn 1B
Last Completed: Semroc Spaceman

Last edited by LeeR : 02-06-2020 at 08:13 PM.
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  #12  
Old 02-07-2020, 04:58 AM
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ghrocketman ghrocketman is offline
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I have flown my Mars Lander on the 18mm D24 and D21 from Aerotech.
Flies great on those (flies great on C5-3s too ). It has a nice kick with the D24, but nowhere near "warp speed".
The Astron Scrambler , Ranger, and Cobra make nice flights on the 3xA8-3 cluster. You can go with 3xA8-5 with empty payload compartments.
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  #13  
Old 02-07-2020, 09:21 AM
john ager john ager is offline
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Quote:
Originally Posted by tbzep
Three A8-3's will give you about a C30-3 with about 7Ns. Mortar shot.



.


Just weighted my Ranger clone. Empty, primed but not painted, I'm at 3.85oz. Figure with paint and vinyl i'll be close to 4.5oz empty.

Ran that through Open Rocket and got about 230 ft on an A8-3 cluster. B6-4's seem like a better choice putting it up around 550 ft.

Either way, i'll fly it on the A8-3's first to see how they perform.
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  #14  
Old 02-07-2020, 09:31 AM
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ghrocketman ghrocketman is offline
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My Ranger is quite light; painted with Aero Gloss Dope instead of Enamels.
I know it gets to over 300' on 3xA8-3
__________________
When in doubt, WHACK the GAS and DITCH the brake !!!
No DIRECT and MEASURABLE Harm=NO Foul advocate

If you are NOT FLYING LOW in the left lane, you need to GET THE #$&@ OUT of it !

Yes, there is such a thing as NORMAL
, if you have to ask, you probably aren't
!
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  #15  
Old 02-07-2020, 10:03 AM
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LeeR LeeR is offline
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Iím going to try my Cobra on A8-3s next time I go out to fly. I bought a lot of them on closeouts at Walmart and Hobby Lobby (Iíve got 22). Iíve flown it on B6-4s and was amazed at performance.

I just looked at my inventory, Iíll have to fly it on B4-4s as well. Iíve got a lot more of them than I realized ó 24! Also acquired on closeouts.
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Projects: Super Sky Hook, Super X-Ray, Estes Phoenix, Big Daddy, QCC Explorer
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  #16  
Old 02-07-2020, 10:33 AM
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ghrocketman ghrocketman is offline
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B4-4s can be "converted" to B14-4s
__________________
When in doubt, WHACK the GAS and DITCH the brake !!!
No DIRECT and MEASURABLE Harm=NO Foul advocate

If you are NOT FLYING LOW in the left lane, you need to GET THE #$&@ OUT of it !

Yes, there is such a thing as NORMAL
, if you have to ask, you probably aren't
!
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  #17  
Old 02-07-2020, 10:37 AM
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tbzep tbzep is offline
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Quote:
Originally Posted by LeeR
Iím going to try my Cobra on A8-3s next time I go out to fly. I bought a lot of them on closeouts at Walmart and Hobby Lobby (Iíve got 22). Iíve flown it on B6-4s and was amazed at performance.

I just looked at my inventory, Iíll have to fly it on B4-4s as well. Iíve got a lot more of them than I realized ó 24! Also acquired on closeouts.

I had a lot of C6-5's and 1/4A3-2T's on Walmart closeouts. I ended up building some larger/heavier cluster payload rockets just to use up the C6's. It's also one reason I started converting a bunch of the 1/4A's to boosters. Pretty cool to see them stage right in front of you.
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  #18  
Old 02-07-2020, 12:48 PM
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LeeR LeeR is offline
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ghrocketman and tbzep,

I am assuming your mods are done with a careful application of a standard drill bit?

I also have acquired a lot of 13mm motors. All of these were bought for sizable discount, and many for $1/pack at a Walmart closeout. I need to build some 13mm clusters, I guess. The booster motors are slowly getting used up by my Double Mini Max.
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Projects: Super Sky Hook, Super X-Ray, Estes Phoenix, Big Daddy, QCC Explorer
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Last Completed: Semroc Spaceman
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  #19  
Old 02-07-2020, 01:08 PM
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ghrocketman ghrocketman is offline
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Have not done any B4 converions in many years, but did NOT use a standard drill bit.
Used a non-sparking bit that I think is brass.
__________________
When in doubt, WHACK the GAS and DITCH the brake !!!
No DIRECT and MEASURABLE Harm=NO Foul advocate

If you are NOT FLYING LOW in the left lane, you need to GET THE #$&@ OUT of it !

Yes, there is such a thing as NORMAL
, if you have to ask, you probably aren't
!
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  #20  
Old 02-07-2020, 01:36 PM
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tbzep tbzep is offline
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Quote:
Originally Posted by LeeR
ghrocketman and tbzep,

I am assuming your mods are done with a careful application of a standard drill bit?

I haven't drilled any cores. I've only converted delay motors to boosters. I cut the motor tube off just above the clay cap to make access easy, then used brass tools to remove the cap, ejection charge, and delay. I then glued the section back on to get a full length motor. I didn't have a brass bit and wouldn't have used one on the initial mods anyway because I didn't want to go to deep and take out some propellant. I've also limited my tasks to summertime so the high humidity would help eliminate static electricity issues. PPE is a must.
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