Loc Goblin Thread
- Thread starter ECayemberg
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Rocketjunkie
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BTW, Here's my 7.5" Goblin on an Aerotech M750, then a RX N800 (in a 98/15360 case).
waltr
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Impressive flights.
Camera person did excellent job keeping it in view on the second video.
Thanks for posting.
Can’t wait to see the Florescent Orange !
What were the respective altitudes, great sounding motors!
Pick a light motor and adapter!
waltr
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Photo in post #271 above.
waltr
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The weight is with the LOC 29mm adapter.
Add a G76 in the 29/40-120 case and launch weight is just under 1500 grams. This is just over 5:1 TTW ratio.
The G76 has plenty of initial thrust for that, nice!
Altitudes? Was it a kit or diy?
Rocketjunkie
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It went 8800 on the M750 and 13000 on the N800.
I built this in 2010 before the kits returned. The build thread is https://www.rocketryforum.com/threads/almost-a-goblin.8709/
It was Blue Tube at first but now has a fiberglass main tube (and gained 8 lb.
)
Were the fins ply or bass and did they get ‘glassed as well ?It went 8800 on the M750 and 13000 on the N800.
I built this in 2010 before the kits returned. The build thread is https://www.rocketryforum.com/threads/almost-a-goblin.8709/
It was Blue Tube at first but now has a fiberglass main tube (and gained 8 lb.
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Carbon fins?
Rocketjunkie
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3/8" ply, no glass. You notice I like long burn motors
waltr
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I have a question on the LOC 4" Goblin. Planning maiden flight on a G76-4G (29/40-120 case). Sims to 500' with enough speed off the rail and will use motor ejection of chute.
However, with a 4" diameter BT there is a huge volume to pressurize to blow off the nose. The G76 reload came with 0.7gram BP. This does not seem to be enough so I added more. Could get 1.2gram into the ejection cap.
Does this seem to be enough BP? Or too much BP?
Is adding BP to fill the ejection cap ok?
How much BP have everyone been using of the LOC 4" Goblin?
However, with a 4" diameter BT there is a huge volume to pressurize to blow off the nose. The G76 reload came with 0.7gram BP. This does not seem to be enough so I added more. Could get 1.2gram into the ejection cap.
Does this seem to be enough BP? Or too much BP?
Is adding BP to fill the ejection cap ok?
How much BP have everyone been using of the LOC 4" Goblin?
I'm using 2.0 grams of FFFF black powder; so I would strongly recommend ground testing. Smallest motor I fly is a 29mm H182R (DMS) but I built mine like a tank and sports a 60" in. parachute so I'm running heavy. Use a disposable nitrile glove to make an ejection charge with an e-match and the wire run through your airframe vent hole. I would reach out to a club member if you do not have any black powder on hand. Make sure the nose cone fit is not too tight. We do ground tests at our club launches; it's for safety and you have worked too hard building your rocket to crash on your first flight. I ground tested a motor ejection Wildman 5"in. Jart and my LOC Goblin prior to flight.
waltr
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Thanks for reply. I do have BP so will do a test today. I'll feed an ematch lead through a used 29mm motor. I'll try 1.2 grams first since this is what I fit into the 29/40-129 case. Have done DD so familiar with testing.
Nose does not fit tight but just snug enough to be able to pick the Goblin up by the nose then it slides off.
Ok, test went well with 1.2gm BP.
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MidOH
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I set my nose cone, so that I can pick the rocket up by the cone. Pick it up quickly and the cone moves a half inch. Shake the rocket and the cone let's go.
Then I simply blow the cone out with my breath from the motor mount. (38mm adapter). If I can blow it out, so can a motor.
Then I simply blow the cone out with my breath from the motor mount. (38mm adapter). If I can blow it out, so can a motor.
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All sounds good
Did you play Tuba in the band?
How am I just now finding the Goblin thread?! I flew my Goblin Sunday for a successful L2 flight on an Aerotech J340. It's a great motor for that rocket, and the flight was a real crowd pleaser! Here's the video:
LOC Goblin L2 Flight - J340
And, because it's such a great photo from Red Glare 2022, here's the Goblin on an Aerotech I327. Photo taken by Jim Wilkerson - Tahoma Photography:
LOC Goblin L2 Flight - J340
And, because it's such a great photo from Red Glare 2022, here's the Goblin on an Aerotech I327. Photo taken by Jim Wilkerson - Tahoma Photography:
waltr
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Aleks,
Great video of the J340 flight and I do remember your Red Glare flight. It was one of the flights there that inspired me to get the 4" Goblin and L1 cert.
Great video of the J340 flight and I do remember your Red Glare flight. It was one of the flights there that inspired me to get the 4" Goblin and L1 cert.
Really glad to hear it was inspiring! Funny you should say that about your L1 because , I saw Joe Zielinski do his L2 at Red Glare on a Goblin with a J270 and it was such a nice flight. That's when I decided to use mine for my L2!
It'll fly great for an L1! What kind of motor you planning to fly? I've flown mine 3 times on an H170, I327, and J340, and I would not hesitate to recommend all 3 motors, as all three were great flights. Guess flight 4 has to be on a K motor to keep that pattern right?
waltr
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Maiden this Saturday will be on a G76. L1 next month on an H238, sims to ~900 feet.
When I get down to MDRA I'll have to have a bigger H (H238 is only 2% H) for a higher flight.
Maybe this will be fine on a J for L2 but have been thinking of extending BT with AV Bay and full reluctant DD (yes I have been flying DD in smaller rockets so it is not new).
I probably saw Joe's L2 flight as well. There were a lot of HPR cert flights.
Slightly off topic from the Goblin thread, but quick aside on that note: My local club had a rocketry team from Penn university show up this past Sunday with 8 of them attempting their level 1s. I think all but one of them flew an H238, and woo, that's a great motor! Oh, and they all got their L1s, which was awesome! The world needs more college rocket clubs and teams!
waltr
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Goblin flew maiden Saturday on a G76G-4. Perfect flight. I braided the nylon cord and the chute did a beautiful slow deploy. Photo on launch. I was quite busy RCO'ing and helping new people so never took a video. Did have a Mobius video camera on board. Still need to edit out the beginning and end (no one likes watching the pad and then the grass) will post later.
We also had 5 kids from the Princeton U rocket club come to do L1 certs. 3 passed, 1 had fouled chute and 1 had a shock cord come off. Most were flying a 38mm H130 motor in Apogee Zephyr.
We also had 5 kids from the Princeton U rocket club come to do L1 certs. 3 passed, 1 had fouled chute and 1 had a shock cord come off. Most were flying a 38mm H130 motor in Apogee Zephyr.
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MidOH
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Did you play Tuba in the band?
Pops easier than a BT50.
All of the surface area on a 4" nose cone, more force. Maybe mine are too loose.
waltr
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I did the 'blow test' on the 4" Goblin and the nose cone barely made it off the BT. Not good which is why I needed to increase amount of BP. 1.2 grams ejects to nose with enough force to pull out the chute but not fully extent the shock cord.
A G76G in a 29/40-120 case comes with 0.7 grams. However, an H238T for a 29/180 case comes with 1.4grams.
The G76 needed BP added but the H238 does not. I will use the full 1.4gram with the H238.
I somehow missed this thread too. Here is my 5.5" Goblin on a J340 at NARAM62 last year:
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waltr
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On board video from above 4" LOC Goblin maiden flight. Camera is original Mobius in an Additive Aerospace shroud at zero degrees.
