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Maxter

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I just finished building a Minie Magg. I tried to build as light as possible and it still seems to be a bit heavy. Mine weights 5 lbs. 5 oz. ready to fly. This includes 9 oz. nose weight, and all recovery gear. So....what does yours weigh? Also, what motors have you flown? And what delay did you use? I use Open rocket and ThrustCurve to simulate flights. Do you find the recommended delays are accurate or do they need adjustment? Thanks!
 

ThePlmbr

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We have two Minnie-Maggs. The one built stock weighs 3.75lbs. The other one with a 54mm motor tube weighs 4.25lbs. We have 2 ozs. of nose weight and they fly straight. Simulated delays are pretty close, except for sparkys, you need to shorten the delay 1.5 to 2 secs.
 

SCrocketfan

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Mine has 9 oz of nose weight, 64 oz total, so 5 lbs 5 oz is a bit heavy. I've flown everything from full G/minimal H (before nose weight added, with 5 second delays) to full I motors. A CTI 3 grain I flies well with a 9 second delay. I540 and I216 (both basically the most impulse in an I) work well with 10-11 second delays, and fast H motors like the 29mm H255WT work with 6-7 second delays.
 

DavidMcCann

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I've built two, and they're right on the nose at 3.3 pounds loaded up with a G76G or G77R. I use 4 second delays, it was a bit early



 
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Maxter

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How do you build so light? I did use epoxy, but was VERY careful. Nothing extra, and I made the smallest fillets I could.
 

Coop

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I flew mine on a lot of 3-grain I's--9 sec delays. Will have to check on the weight.


Later!

--Coop
 

grouch

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Mine started life around 4lbs. They don't need nose weight. Mine flies best on I's. if I were to build another one I'd build it with a 29mm and fly it on a 29/360 case. That would reduce the butt weight and increase the stability. Much more than I's is a handful for the rocket anyway.
 

crossfire

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I have been flying mine on the AT DMS H550 ST. I think 4 times this summer. Set delay at 6-7 sec. works perfect every time.
 

Swissyhawk

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Master - yours seems kind of heavy. What kind of scale are you using? How well do you trust it? Just a thought.
 

llickteig1

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Why in the world would you add so much (if any) nose weight to a Minie Magg??? You're going to regret doing that. That heavy nosecone will kill that rocket.
 
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H_Rocket

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They don't need nose weight.
^^This

I built mine with a 54mm mount and it is just over4# - Flies like a champ on the Loki I405 for about 2200'. Karen's weighed about the same after several repairs up to it's untimely end. I405, H144, I210 all Loki, and a bunch of 38 3G CTI. Never had an ounce of nose weight in either.
 

Coop

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Mine was overbuilt as one is wont to do with their L1 bird. I recall using epoxy and epoxy clay fillets. I may have even used some of the epoxy clay to fill in spirals, but I can't be 100%. Anyways, mine's 3.95lb dry. No nose weight.


Later!

--Coop
 

jrkennedy2

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I must have sim'ed mine wrong because it claimed with a 4gr 38 it would have less than 1 caliber of stability. I have read recently there is a slightly different way to calculate stability on short - wide bodies... Regardless, I stuck 4oz of b-bs in the nose with a dowel inserted sideways through the NC to hold everything in. She is slow and fun to watch but my next one will have an empty nose to see how that works.
 

dhbarr

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I must have sim'ed mine wrong because it claimed with a 4gr 38 it would have less than 1 caliber of stability. I have read recently there is a slightly different way to calculate stability on short - wide bodies... Regardless, I stuck 4oz of b-bs in the nose with a dowel inserted sideways through the NC to hold everything in. She is slow and fun to watch but my next one will have an empty nose to see how that works.
Yup, MM is the very definition of a short fat rocket whose stability is largely influenced by base drag.
 

Tonimus

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I must have sim'ed mine wrong because it claimed with a 4gr 38 it would have less than 1 caliber of stability. I have read recently there is a slightly different way to calculate stability on short - wide bodies... Regardless, I stuck 4oz of b-bs in the nose with a dowel inserted sideways through the NC to hold everything in. She is slow and fun to watch but my next one will have an empty nose to see how that works.
Drill out the rod and bang out the bbs. Then cut a new rod to fill the hole.
 

Buckeye

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^^This

I built mine with a 54mm mount and it is just over4# - Flies like a champ on the Loki I405 for about 2200'. Karen's weighed about the same after several repairs up to it's untimely end. I405, H144, I210 all Loki, and a bunch of 38 3G CTI. Never had an ounce of nose weight in either.
I am in the minority, here. I have two MMs, and I hate them. They fly unpredictably, especially on largish I motors. I think some nose weight is needed, and I have tried several iterations, but have yet to dial in a good amount. The only other thing I can think of is that my MMs have both a hefty 1/2" launch lug and rail buttons, which may create some non-symmetric Cp/Cd phenomena to throw the rocket off course.

Plus, "short and fat" is just wrong for rockets! :wink:
 

Banzai88

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For rockets with a Length : Diameter ratio less than 10:1, base drag can be simulated by placing a 0 mass transition cone with the point on the bottom of the rocket (Pi*body) diameter in overall length. There is some debate as to whether length includes the nose cone or not. Either way, the MM is a classic 'needs base drag cone added to sim correctly' rocket.

More info in Peak of Flight #154, 157, 162.
 

ECayemberg

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I am in the minority, here. I have two MMs, and I hate them. They fly unpredictably, especially on largish I motors. I think some nose weight is needed, and I have tried several iterations, but have yet to dial in a good amount. The only other thing I can think of is that my MMs have both a hefty 1/2" launch lug and rail buttons, which may create some non-symmetric Cp/Cd phenomena to throw the rocket off course.

Plus, "short and fat" is just wrong for rockets! :wink:
Another member of the minority club here...seconded.

While I'm no pro, I bet I have more Magg flights under the belt than most. 22 flights and counting on my original Magg, 8 and counting on "FrankenMagg", and another couple on two other Maggs...have 4 in total, really like a Minie Magg for sport flying! I organized the "Great Minie Magg Drag Race" in concert with TWA for many years...some years we had 20+ Maggs drag racing. Good times.

Nevertheless, I've flown Maggs with and without nose weight. Most Maggs will fly fine without nose weight on most motors; I hate blanket statements and those that say no noseweight is ever needed is irresponsible in my opinion. I have seen several Maggs fly unstable....#1 rocket related pet peeve: know your CP, check your CG, all will be well.

Regarding the Minie Magg, note that the current fin shape is different than that of yesteryear....current has a straight trailing edge (no aft sweep). Also, some fins are/were surface mount, some TTW with the Loc plate thingies, and I've seen them TTW all the way to the fin tube. I have Loc 5.5" short nose cones from the early 90's that have a thinner walls than the current offerings and therefore are lighter than current offering of the same item. I have seen Maggs with 54mm and even 98mm mounts....a lot of variables (I know these would be considered exceptions). Bottom line, know the CP, check your CG, make sure you have sufficient stability before proceeding; a simple task yet a seemingly lost art! Blanket statements on a rocket with marginal stability are dangerous, in my opinion.

My closing thought. Have flown Minie Maggs a lot, and have been witness to many other Magg flights over many years of flying, I believe that a few ounces of noseweight seems to help a Magg fly more predictably on a regular basis. The old timers will enforce that the Minie Magg established an early reputation of taking unpredictable paths off the pad....rails of today seem to help a bit vs. the rods of yesteryear, but I still see them flying every which direction. IMO, 4oz of noseweight in a heavier Magg is a decent idea....if you have a heavier Magg, that extra weight is all in the rear guaranteed.

Your mileage may vary. Have fun and fly safe!

-Eric-
 
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bobkrech

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I built my L2 cert Warlock stock and it weighed 108 oz. without the motor, only 8 ounces more than the published kit weight. I used wood glue, did not fillet the fins, added motor retention and an ironing board fabric chute protector and 6 oz. of paint.

The stock Mini Magg kit weight is 40 oz., enough wood glue or epoxy will add less than 2 oz., a sufficient motor retainer less than 1 oz., paint less than 3 oz., less than 1 oz. for a parachute protector, and then less than 6 oz. for a G motor, so a stock built Mini Mag loaded with a G76 thru G80 will weigh less than 1500 g or 3.3 pounds as per the instruction sheet.

You do not need a fin fillet for strength as the "LOC-N-FIN" construction is extremely strong and stiff enough for any motor you can put into the stock motor tube. If the kit is build to the stock configuration, it will not need nose weight. If you make it heavier, the weight will be in the aft section as previously mentioned, and then you may need nose weight.

You should be able to sim your rocket as built in any simulation program and determine the appropriate delay for your rocket if you use the mass override feature in the sim.

Go to http://www.thrustcurve.org/guidepage.jsp and input 5.5" OD, 5.5 pounds or whatever the weight of your rocket is, 38 mm mmt or whatever your motor diameter is, and 13" motor tube length, simple rocket, average drag. For the values above, the delay range is between 5 to 8 seconds.

If you play with the sim, you will find an H motor with a 6 second delay or an I-motor with a 7 second delay will be close enough (provided the average thrust >80 N) in a Mini Magg weighing between 3.5 to 5.5 pounds without the motor.
 

DavidMcCann

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I did have the thinner fins, which are always warped. even if you skip fillets, it's easy to fix. just a short tab of glue like this handles it

 

Buckeye

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You do not need a fin fillet for strength as the "LOC-N-FIN" construction is extremely strong and stiff enough for any motor you can put into the stock motor tube. If the kit is build to the stock configuration, it will not need nose weight.
Well, your "stock configuration" is not what LOC recommends in their "stock" instructions:

http://locprecision.com/wp-content/uploads/2015/09/PK-68-Mini-Magg.pdf

LOC suggests epoxy throughout, "slathering" of glue, and additional fillets to the fins and launch lug. This then opens the door to a wide range of interpretation and execution, resulting in ass-heavy Mini Maggs. Then, LOC neglects to mention nose weight as a counter measure. Not good documentation in my book, especially given how old the kit is and the thousands of flight observations.
 

crossfire

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I would do a small fillet if nothing else just to seal up fin slot to the fin.
 

grouch

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Seriously guys, we should all know CP/CG and adjust accordingly. If overbuilt you may need nose weight but that's up to you to decide. No hand holding needed. If you ask me, manufacturers should just put parts in a bag sans instructions. Most don't use them anyway. They can't account for every modification such as motor retainers and heavy shock cord anchors.
 

Buckeye

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Seriously guys, we should all know CP/CG and adjust accordingly. If overbuilt you may need nose weight but that's up to you to decide. No hand holding needed. If you ask me, manufacturers should just put parts in a bag sans instructions. Most don't use them anyway. They can't account for every modification such as motor retainers and heavy shock cord anchors.
That is too extreme. When I plop down $120+ for a "kit", I expect some documentation. LOC, and Minie Magg in particular, are touted as the perfect Level 1 rocket for HPR newbies. You know, "low and slow." Many of these builders need some hand holding, as evidenced by the basic questions posted on this forum. Given that nobody really knows where the CP is located on the Mini Magg or how to properly simulate it, the manufacturer should error on the side of caution for this kit.
 

DavidMcCann

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That is too extreme. When I plop down $120+ for a "kit", I expect some documentation. LOC, and Minie Magg in particular, are touted as the perfect Level 1 rocket for HPR newbies. You know, "low and slow." Many of these builders need some hand holding, as evidenced by the basic questions posted on this forum. Given that nobody really knows where the CP is located on the Mini Magg or how to properly simulate it, the manufacturer should error on the side of caution for this kit.

Having built and flown a couple, this really isn't a hand holding situation. Build it, fly it. If you don't get stupid, you're fine. I've done one epoxy, one wood glue. Even done generously, it's a 12 piece puzzle. Now, if you start tossing around fiberglass on the fin tabs, doing 1" radius fillets, dumping half a pound of lead in the nose, yea then you're going to have issues.

LOC recommends G,H and I motors. If you stick to that and a "stock" build you're (generally) good. No rocket science here. The CP isn't a mystery. There are ways to simulate base drag, but personally I just shoot for .5 cal in rocksim.

As to it being the perfect L1, I think it's a terrible L1. The LOC IV or an Athena3 would be much better.

it's moot though, as LOC kits do come with basic documentation.

As for the larger argument on instructions, they're nice to have, but I don't think you can account for every type of build. Madcow includes them, and I deviate pretty quickly from them. MAC includes a good set, and I get slightly off track from those. Widman prefers to have build threads done here, and while informative, even those I choose a bit from this one, and some from that one, and do my own thing in other places.

If there's something unique about a build, documentation is good.... but for a general basic rocket...there's just so many ways to do it trying to cover each style of build would require about 10 sets of directions, or a massive confusing 'choose your own adventure' style book. A basic set is nice for rookies to follow, but I'm not going to get all twisted if I get a box of parts and a bunch of packing peanuts.
 

Buckeye

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I am just a stickler for good documentation in everything. Overall, LOC's are pretty good, and even include pictures! The most useless instructions are the ones that are just poorly-worded text with no images and vague references to part orientations. I won't mention any names... :wink:
 
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