Minie Magg on a G76?

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EBurg

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Hi Folks–
First time poster but long time follower of TRF. I’m completing my first HPR build – Minie Magg, and planning on going for Level 1 Certification at the next Tripoli launch on August 13th.

This was my first time epoxy build, and I tried to build it light, but the total weight of the rocket (including loaded engine) is coming in around 4#. I’d like to give this a try out before I go for my certification flight but feeling mixed on it’s performance with a G76-4 engine.

Open Rocket predicts about a 400 foot launch and 30mph at the end of the rod, so it looks safe, at least on the computer. I know it’s not quite at the 5x impulse range for average thrust, but the G76 has a pretty strong initial push that looks like it should be ok.

Has anyone flown a Mini Magg at the 4# range with a G76? I’ve seen some successful flights logged at the 3.3# range, but nothing that heavy. Any thoughts?

Thanks in advance – this forum has been a great learning tool for me.
Eric
 

djs

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Stability in this case would depend on the wind.. anything more than calm would cause issues. Personally if it were me, I'd try something with a little more punch, like a G138WT CTI load.
 

rharshberger

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Hi Folks–
First time poster but long time follower of TRF. I’m completing my first HPR build – Minie Magg, and planning on going for Level 1 Certification at the next Tripoli launch on August 13th.

This was my first time epoxy build, and I tried to build it light, but the total weight of the rocket (including loaded engine) is coming in around 4#. I’d like to give this a try out before I go for my certification flight but feeling mixed on it’s performance with a G76-4 engine.

Open Rocket predicts about a 400 foot launch and 30mph at the end of the rod, so it looks safe, at least on the computer. I know it’s not quite at the 5x impulse range for average thrust, but the G76 has a pretty strong initial push that looks like it should be ok.

Has anyone flown a Mini Magg at the 4# range with a G76? I’ve seen some successful flights logged at the 3.3# range, but nothing that heavy. Any thoughts?

Thanks in advance – this forum has been a great learning tool for me.
Eric
My experience has been that 4# rockets are marginal for motor deploy (@ 500' aapogee) as a 4 second delay is about a second or so too long for comfort and if you get a "Bonus delay" then you also get a broken rocket. In my case I use electronic deployment for rockets of that weight and altitude. A G76G has an initial thrust of 196 newtons which is a 11.1:1 T:W ratio. If using OpenRocket doublecheck the length of the launch rod/rail in the simulation settings and set it to match the actual rail or rad that will be used.
 

jimzcatz

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Don't do it. As you are new like you said, there is a term called "it mini-magged". Guys have gotten better, but (no lie), almost 85% of all minimagg flights I have witnessed veer off sharply one way or t'other upon leaving the rod /rail. Hence the term "mini-magged". Good luck, be safe. I would choose a G138.
 

fyrwrxz

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^ pretty much whut everybody else says. look up Thrustcurve.org and put your stats in there. You'll see this is a pretty iffy combo.
 

DavidMcCann

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I've done a 3.3 pounder on a G76. any more is really pushing it... At 4 pounds that's a solid L1 bird.

 

Nathan

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Found this video of a Minie-Magg on a G76. Looks a little too slow leaving the rail for a Minie-Magg. I would use a faster burning G motor.

[video=youtube;AvTzM94YCwQ]https://www.youtube.com/watch?v=AvTzM94YCwQ[/video]
 

EBurg

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Thanks everybody - I'll hold off and fly this one on the H128 I was originally planning on certifying with. I'll have to build another rocket to use the G76's with.....
 

djs

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Good choice- better to play it safe than have the rocket fly squirrelly and end up wrecking your L1 before it even started!
 

Rocketjunkie

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If it is stock weight, it will fly on a G76-4. Don't try it if the wind is over 5 mph.
 

Buckeye

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Don't do it. As you are new like you said, there is a term called "it mini-magged". Guys have gotten better, but (no lie), almost 85% of all minimagg flights I have witnessed veer off sharply one way or t'other upon leaving the rod /rail. Hence the term "mini-magged". Good luck, be safe. I would choose a G138.
Agreed. I have two Minie Maggs, and most flights were squirrely. I made many mods with rail buttons, noseweight, ebays in the nose cone, and higher thrust motors which helped some. Never understood why this kit is so popular - it needs a lot of TLC.

I suggest an H242 as your cert flight.
 

DavidMcCann

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because it's huge and cheap, and built stock, it flies just fine ;) pro tip: use wood glue.
 

grouch

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I love mine but it won't ever be flown on a G. Mine flies great but it does a have a mind of it's own from time to time. Hugely entertaining and a lot of fun to fly....on an H or I.
 
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