Loc Magnum opinions.... need to glass? and airstart wiring??

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mcOrbit

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Hi gang!

Just getting ready to mark and cut the fin-slots on a Loc Magnum and was wonderin':


1st: Should or do I need to glass the fins the tube or both, or am I adding unnecessary weight to the beast.

The biggest motors I see putting in would be a k 550 my normal launch would be a j350 and 2 g40's or 2 h50's


2nd: Air-start wiring! can I just run the wires through the body tube around the motors to some terminal blocks or will they (wires or terminal blocks) just melt.

...mark
 

Missileman

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I would lay a strip of glass in the fin joint but wouldn't suspect you would need any more than that.(assuming you get some fair internal fillets)
Don't have an answer for the wiring question.The only airstarted motor I have done, I used lamp cord tubing and run the igniters through it to the electronics, but it is a smaller rocket and the distance is fairly short.
Welcome to TRF.
 

Ryan S.

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I would glass the body tubes, and then attatch the fins with some nice thick milled glass fillets

on the outside I would do a tip to tip as well. This will add flight strength although none is needed for in flight stress with the motors you mentioned HOWEVER, since the fins of the magnum are swept, you might want the extra strength on there for when you land the rocket
 

Rocketjunkie

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The 3" motor mount version built without any fiberglass, flew on 5 midrange L motors including a L1060GG. (Larger motors would have broken the waiver.) It has been retired, still flyable. I also had a standard version except with 6 outboard 29 mm mounts and altimeter bay. It survived all the motors I put in it including K1100, K700, and Kosdon L850. There was no glassing on this rocket either. After many flights, stress marks developed just above the fins but I kept flying it until a recovery failure resulted in a lawn dart.
 

wickball

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Mark- I just completed one for L2 cert, no glass, am planning on using only J and K motors, hope to cert in 2 weeks.

Rocketjunkie- I built my Magnum to have interchangeable coupler/ electronics bay. Engine ejection for cert flight, electronics later. Did you use drogue chutes with your Magnum; if so, what brand and size?
wick
 

rocketmanMV

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I've flown my Magnum countless times in all sorts of configurations with no glassing at all. My favorite combo was two H220s with an I284 in the middle; light em all at the pad; the Blue Thunder would boot the bird up 200 feet, then the White Lightening would come up to pressure for a crowd pleasing "air" start.

Sadly, that rocket is dead, the victim of a cato. RIP.
 

Rocketjunkie

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Originally posted by WICKBALL
Rocketjunkie- I built my Magnum to have interchangeable coupler/ electronics bay. Engine ejection for cert flight, electronics later. Did you use drogue chutes with your Magnum; if so, what brand and size?
wick
No drogue, just 50' of 1/2" TN. Both parts are unstable once separated. My electronics were in the coupler also. The main was the chute that came with the kit. There was plenty of room in the payload section for the main and 15' of TN.
 

n3tjm

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My favorite rocket is the Magnum... Flown it naked many times... Only a few flights were with single motors... most had clusters. Two had airstarts... one crashed...

I finally gotten around to glassing mine externally. Here is a picture. You can see how I divided mine in sections. The airstart timer mounts to a plate on the 54mm tube. Dual deploy is in a LOC 5.5" alt bay. Mine is heavily mod.



Only have a couple more colors to go ;).
 

DynaSoar

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Originally posted by mcOrbit
1st: Should or do I need to glass the fins the tube or both, or am I adding unnecessary weight to the beast.

The fins don't hang below the body. The body will usually hit the ground first, making it less likely the fins will. The fins are designed to handle the flight load. There's no reason to strengthen the fins. If you do, a strip of glass under the fillets is plenty and then some. Adding more glass adds more weight and makes it come down faster, and increases the chances of it hitting hard enough that it might break a fin (in the unlikely event it did land sideways or catch a wind gust). Of course then you could just use a bigger chute. Of course you could do that anyway and not worry about glassing.
 

Ryan S.

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Originally posted by DynaSoar
The fins don't hang below the body. The body will usually hit the ground first, making it less likely the fins will. The fins are designed to handle the flight load. There's no reason to strengthen the fins. If you do, a strip of glass under the fillets is plenty and then some. Adding more glass adds more weight and makes it come down faster, and increases the chances of it hitting hard enough that it might break a fin (in the unlikely event it did land sideways or catch a wind gust). Of course then you could just use a bigger chute. Of course you could do that anyway and not worry about glassing.
They come very close, and they are also swept, therfore there is almost a 100% chance of them hitting the ground first, the only way this wouldnt happen is if the body was coming straight down (which due to the recovery eyebolt on one side wont happen)

There are many reasons to strengthen the fins, it is not going to add more than half a pound of overall weight. Even if your fins are strong enough in the first place that aft corner is going to get bashed from repeated landings and strengthening is not going to hurt. Another thing, if the rocket lands on its side repeatedly the fins may become warped.

btw I have seen plenty of magnums do fin stands on one of their fins (DAN)

So, unless you know for a fact that your rocket is going to have a perfect deployment ever time, and it is going to land on soft ground everytime, I can definantly see stregthening the fins with some glass.

Another thing; Loc tubes are not durable, at all, and glassing them is a great idea because they often peel and get gross at the end....that is just my experience
 

Stymye

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hmmm,with all those problems

I't amazing how many unglassed loc rockets have been sold, built and are still flying.
 

Chuck Rudy

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I learned early on to glass, or those little spirals in the tube would eventually become a crack in the paint and then lead to the demise of the body tube. Fins lever themselves off, fins chink and crack. A few of mine had early retirements to material fatigue. You can fly without reinforcing anything, it's just the longevity factor, and you have substantially increased your abililty of your rocket to survive the abnormal.

My first L2 attempt was a CATO, fortunately because of the glass and G-10 fins the rocket survived and it was a success the next day. It then survived one of those wonderful Aerotech 1 second delays, deployment at full thrust with no zipper. It still flies after all the abuse.

So you don't have to reinforce a thing, unless you want to fly it for a lot of years, and want to increase the survival factor should you CATO, land on a rock, land on a driveway, smack a tree, have premature ejection, even survive a night lost in the rain.

And if you fly with electronics, their survival increases with the strength of the rocket.

It's all up to you, it's whatever you can afford. ;-)

Chuck
 

daveyfire

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Originally posted by stymye
hmmm,with all those problems

I't amazing how many unglassed loc rockets have been sold, built and are still flying.
Indeed... I have several LOC kits from 1995-1996 that are still flying great... my Expediter (second high power rocket, no glass, stock shock cord mount) has flown several flights on everything from I211s to J180s to I435Ts (what a motor for this rocket!) with no problems at all. I've sent unglassed LOC rockets through Mach without problems.

The weakest portion on the Magnum is the tube coupler -- the LOC 5.38 couplers are notoriously weak, and are often the cause of failure for these rockets. I recommend either double-walling it (using one of LOC's "stiffy" tubes, perhaps) or putting a few wraps of glass/carbon/whatever on the inside to prevent folding or buckling. A dual-deploy setup inside will help immensely too, as the board running up the center of the tube, in combination with double bulkheads and allthread, will definitely keep everything together.

HTH!
 

DPatell

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Yea, I have some Magnum experience.

The only fin trouble I had was the tube right above the fins getting crimped on it's first flight. Little bit of glass and there was no issue.

My new one has 1/4" fins without tip to tip glassing, just big fillets. Landed without a main on a K695R, stuck the fin in the ground, and no damage...has flown on K1275R, K600W, K1100T since with no trouble.

As Davey said, it's the coupler to worry about. I used one layer of 4oz on my LOC coupler, stood up to everything up to a K670GG.
 

DPatell

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Original, unlgassed Magnum on a K670GG to 4493'. Weighed 14 pounds even.
 

DPatell

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New Magnum out to hit REAL hard. No damage.
 

Ryan S.

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maybe it is a K idk.


The K1275 in the image name means nothing I am sure
 

n3tjm

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Originally posted by Ryan S.
maybe it is a K idk.


The K1275 in the image name means nothing I am sure
I did not see that.... I seriously need to get new glasses.... :(.
 
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