New to rocketry, jumping right in - have many questions

muddymooose said:

This. Last week I crashed my LOC Warlock into a corn field with my Altimeter 3, JLCR, CTI 54mm 3G and fancy chute, and lost over $500 just like *that*. And I allegedly know what I'm doing.

Then there's the safety thing, which is first and foremost to all of this. Personally if I was RSO'ing (and I have yet to do that) and someone new showed up with an Estes and a C motor I wouldn't think much about allowing it. But if someone came up with a 3 pound rocket and a G motor and declared it was their first ever rocket flight, I would be going over the construction and assembly with a fine-toothed comb.

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I have flown rockets for 50+ years now, but I am new to HPR. I bought a LOC 4" Phoenix for my flights. Great kit, Jay gave a lot of good advice, and others, flew her for the first time last weekend and got level 1 with her. Would have done level 2 with same rocket, but low ceiling. LOC products are great, best CS out there. I would get a kit that most people know are built well, one that you can do both certs on. Good luck.

PoweredBySoy said:

Yeah, I'm hearing it's best to get a fat rocket that won't go so high on G's and H's for L1 cert. So I'll probably get something in that realm. But also, I have to like the rocket too - and be excited to build it. I'm eager to get to something bigger though. I feel like working on such a small rocket brings about it's own unique set of challenges for me. I generally have 'fat fingers'.

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i'dd still vote for the 5.5 loc mini magg upgraded to 54 mmt. it can launch with a G80, but really wicked on a J90.

PoweredBySoy said:

Alright, I ordered my rocket! .... a Madcow cardboard Mini Squat. I can fly this little guy on Estes D's and E's to get me started.

Well, gentlemen, you successfully squashed an old mans dreams. I hope you're happy!

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No one is trying to squash your dreams, just trying to keep them from turning to a nightmare. Most of us have seen multiple times when someone gets excited by "the big stuff" and tries to start there. Then if their rocket crashes and/or burns it turns the off to the hobby just as fast. Many of us speak from hard-earned experience.

Madcow make some great stuff, and the Mini Squat is a lot of fun. It is a great place to start. I also like their Squat and have a couple of them--but you need to know how to build and balance a high power rocket to be successful.

By all means, go to your local club's launches. A lot of folks are very welcoming and happy to show off our toys. And you will likely notice that many of us who have been flying for decades and are certified for high power still fly LPR/MPR from time to time.

As for cameras, search on YouTube for "rocket, keychain camera". You will find a number of videos made by folks launching LPR with a model 808 keychain camera taped on the side. I usually buy mine from Amazon for less than $10, and they actually produce some watchable video. It is a good place to start.

I've only been back into rocketry over the last couple years but got bitten by the HPR bug. I got the LOC IRIS (3") for my L1. Haven't launched it yet. But I'm very impressed with the quality of the build. Very solid from what I can see. It will do nicely. Definitely would recommend LOC now that I've built one.

The instructions weren't quite clear as to where to place the lugs. More or less it said to place the first one at CP. Then reading online, most people seem to suggest placing a second lug just aft of CG. So that's what I did. They're pretty close together, but I suspect that's normal with such a small rocket.

CG was taken with an E9 motor in place.

I wish I had a rod to help with alignment, but I used what I had on hand.

I know buttons would probably be preferred, but I just used what I was given.




The local club launch for tomorrow was postponed until next Saturday, so I'll get a few extra, much needed days with the rocket.

Welcome! It's terribly exciting getting revved up for that first build. I can FEEL your enthusiasm clear out here (in the middle of the Pacific ;-)

It took me about 4 months to scratch build my L1/L2 rocket. And I learned more than I thought possible. (only because I didn't think there was that much to learn - it's just another rocket, right?) Wrong. Dead wrong. In fact I built two identical ships, side-by-side knowing from all the youtube I watched that a CATO was possible. It took me 4 flights to complete Level 1 & 2. #1 fatally zippered. #2 Lvl1 success. #3 thought lost forever (there went $600 - bye-bye birdie!) #4 lvl 2 success. #3 was found 3 days later with a small zipper in the side. I was extremely thankful I made two rockets. I flew them both, and repaired them both.

It doesn't matter how careful you are, stuff way beyond your control happens. If you're not willing to toss the cash in the dumpster or the desert, then maybe back up a step or two and test on smaller less-expensive airframes.

Here's a couple of suggestions. On epoxy. I used 5-Min 2-part, RocketPoxy, FixIt epoxy, JB weld, Bond Aide (in the field repair), and PC epoxy. As well as wood glue and super glue. I will never use JB weld or PC epoxy again. They are so incredibly hard to sand. Just don't. Unless you love to sand. FixIt was the easiest to sand and works beautifully when thinned with pure alcohol. RocketPoxy is somewhere in the middle (in terms of sanding.) I found FixIt to adhere best to plastics (I don't mean fiberglass - I didn't need to glue to any fiberglass) - with proper surface prep, FixIt adhered best. RocketPoxy was the worst. I will admit that at first I didn't do a good job of prepping the plastic surfaces and RocketPoxy just fell off. Lesson learned. I never did discover a sure-thing for epoxying to aluminum. *sigh* - there's still more to learn. ;-)

RockSim. I use OR (Open Rocket) in the classroom and RockSim for all my design and simulation work. I've been a bit baffled when reading complaints that one has to pay for it. I'm thrilled to pay for such a solid piece of software that does what it claims it will do with such stability and accuracy. Absolutely no regrets. The folks who spent their time and knowledge to develop RS have well-earned my dollars and loyalty. OR is great in the (elementary STEM) classroom since it is free after all, and it does what the students need to do without much fuss. But, RS has a broader feature set.

Your dreams smashed? No Way! You're going to have more fun than is legal and no one can stop you

Pics of my Cert vehicle, the Rudy III. 38mm 4" BlueTube. The first test flight on a G.

PoweredBySoy said:

LPR doesn't interest me. I want to go loud and fast, and for multiple reasons I've decided to go with the Madcow ARCAS for my first rocket.

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" Speed costs money . . . How fast do you want to go ? " ( an old "Speed Shop" saying )

A few internet images to "light your candle" - LOL !

And so, it begins !

Dave F.

I did it!



Had two successful launches with the D12-7. Rocket was working great and ready for more, but I ran out of motors. I had the E9's with me, but given the conditions they advised me not to do it, and that I would most likely lose the rocket. I was a little bummed. The next launch meet is next Saturday, so hopefully the wind will be down and I can try the E's then.

As predicted, everybody I met was super friendly and helpful. I am now ordering my next rocket.

Ez2cDave said:

View attachment 366362 View attachment 366363 View attachment 366364

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Aaaaarcas

Congrats, you’re now official or something.

With the D12-7, when did you get ejection? Was it anywhere close to apogee? I’d think it would have had to be coming down pretty good by then.

PoweredBySoy said:

I did it!

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That looks familiar...

neil_w said:

Congrats, you’re now official or something.

With the D12-7, when did you get ejection? Was it anywhere close to apogee? I’d think it would have had to be coming down pretty good by then.

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No, it was definitely after. I'm going to look for 12-5's for the next launch.

neil_w said:

Congrats, you’re now official or something.

With the D12-7, when did you get ejection? Was it anywhere close to apogee? I’d think it would have had to be coming down pretty good by then.

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PoweredBySoy said:

No, it was definitely after. I'm going to look for 12-5's for the next launch.

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Congratulations.

Yeah, OpenRocket predicted a lawn dart on a D12-7. I am a little surprised that the sim posted-up by the mfr. was that far off. If you have a scale you might try overriding the calculated mass and CG with measured values, see what it does to the predictions. For a small field, a longer delay might be the better load.

Well, unfortunately after closer inspection it appears my little rocket may have suffered irreparable damage. Looking down inside the main tube I can see that the shock cord has essentially 'zippered' nearly 75% of the forward centering ring. I followed the Madcow instructions, but apparently the cord wasn't anchored well enough and came unwound a bit during chute deployment. I can tug hard on it and it doesn't move - it's still holding on! - but I don't dare use it again for a launch.

So I've ordered a new Mini Squat. It's a good rocket I think, and certainly has a place in my heart for being my first. This time I'll make it Better. Faster. Stronger.

jlabrasca said:

Congratulations.

Yeah, OpenRocket predicted a lawn dart on a D12-7. I am a little surprised that the sim posted-up by the mfr. was that far off. If you have a scale you might try overriding the calculated mass and CG with measured values, see what it does to the predictions. For a small field, a longer delay might be the better load.

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My finished weight was 3.6 oz, which is .4 less than the Madcow listed weight.

I measured my own CG (string) when it was finished.

I still haven't fired up any software. I have a trial key for RocketSim though. Maybe I'll try it out for this next build.

At MDRA, they often say, "If you don't want to lose it, don't launch it." While amusing, there is some truth to it. If you have a kit that is sentimental and want to keep it, retire it. All three rockets that I certified with eventually got lost or destroyed. Thankfully, I have pictures. But, I always figured rockets were for launching, and I would rather have the fun of launching them than to build up a collection in the basement.

So, I say, take everything you learned and go build a better one!

PoweredBySoy said:

My finished weight was 3.6 oz, which is .4 less than the Madcow listed weight.

I measured my own CG (string) when it was finished.

I still haven't fired up any software. I have a trial key for RocketSim though. Maybe I'll try it out for this next build.

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How far from the nose was the CG?

As for the rocket being fatally wounded,

PoweredBySoy said:

Looking down inside the main tube I can see that the shock cord has essentially 'zippered' nearly 75% of the forward centering ring.

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Not quite sure what a zippered centering ring would look like. If you can post some pictures of the damage. There are folks on the forum with experience making repairs.

Very late ejection from the D12-7 could certainly have been a factor in the zippering, but I too would like to see what a zippered centering ring looks like. Pics or it didn't happen!

I'll try to get a pic, but it won't be easy.

Here is how it was anchored to the MMT



Then just imagine the cord cutting through the centering ring as it went around the tube.

neil_w said:

Very late ejection from the D12-7 could certainly have been a factor in the zippering

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I certainly considered that.

jlabrasca said:

How far from the nose was the CG?

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The picture I posted at the top of the page shows the CG and CP marks.

PoweredBySoy said:

The picture I posted at the top of the page shows the CG and CP marks.

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Thanks. I was thinking of a measured value, to plug into Open Rocket to see if the sim still predicted ground-hit before deployment for a D12-7.

PoweredBySoy said:

I'll try to get a pic, but it won't be easy.
Here is how it was anchored to the MMT

Then just imagine the cord cutting through the centering ring as it went around the tube.

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Imagining this...

the rings are plywood, yes?

EDIT - Just realized the spiral would start from the outside of the ring, not they inside... not going to redraw it.

jlabrasca said:

Thanks. I was thinking of a measured value, to plug into Open Rocket to see if the sim still predicted ground-hit before deployment for a D12-7.





Imagining this...
View attachment 366608
the rings are plywood, yes?

EDIT - Just realized the spiral would start from the outside of the ring, not they inside... not going to redraw it.

View attachment 366609

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I would imagine it would cut straight to the MMT, not in a spiral.

Got the new rocket and built the MMT last night. The area in question is now much more reinforced.

PoweredBySoy said:

I'll try to get a pic, but it won't be easy.

Here is how it was anchored to the MMT

Then just imagine the cord cutting through the centering ring as it went around the tube.



I certainly considered that.

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I usually run that shock cord under the CR inside.

Middle of winter and the local rocketry has been seasonally slow, but the next scheduled launch is Jan 26th and I'm just about done with my Mini Squat (Take 2). It's the same kit as before but things turned out a little differently with this one. I reinforced that centering ring that failed the first time. I'm also opting to go with dog barf for this rocket and left the blast cloth off - which was a pretty tight fit in the last rocket. I'm also going with a thinner, one-piece kevlar tether. This was much easier to work with and packs easier.

But I have a concern with this tether. Due to how thin it is, I'm worried about it zippering right down my body tube during ejection. An idea I have is to epoxy a game die (or something similar) right at the point of the maximum extension, thereby greatly dispersing the pressure on the tube. What do you guys think of this? It's minimal weight, and I don't expect the ejection to damage the die at all.

I also had a CG issue with this rocket which I didn't have in the last one. I think the main reason for this is that the motor is seated more aft in this build. I probably should have positioned the motor tube more forward. Anyway, I had to dump about .7 oz of lead sinkers into the nosecone, but now the CG is about perfect. She's packin' a little more weight this time around.

I'll let you know how it flies.

Our club honcho does what you are doing with the die, but instead he uses a small foam ball. Some people also use a strip of masking tape folded over. Anything to widen the contact point and prevent the zipper from starting. Additionally a swipe of CA on the inside lip and top edge of the body tube will harden and reinforce the tube.

kuririn said:

Our club honcho does what you are doing with the die, but instead he uses a small foam ball. Some people also use a strip of masking tape folded over. Anything to widen the contact point and prevent the zipper from starting. Additionally a swipe of CA on the inside lip and top edge of the body tube will harden and reinforce the tube.

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Okay, it's good to know that my idea isn't completely crazy then. I just chose the die because I have a bunch lying around, drilled a hole, bam, done.

I used a wiffle golf ball on one.

The rocket did well! Had two successful launches, and then on the third launch I lost the nose cone. The rocket landed safely, but once I picked it up I noticed the cone was gone. The knot in the kevlar cord still looked intact, so I'm guessing the plastic "loop" of the nosecone broke. I spent a while looking for the cone but wasn't able to recover it.

For my next build I'm thinking of going fiberglass - just for a stronger rocket and to learn the material.

https://www.madcowrocketry.com/1-6-fiberglass-mini-cowabunga/

I notice with this kit that it doesn't come with any sort of motor retainer, or a thrust ring. If I want to keep using the Estes single-use motors, what do you guys recommend I use for retention??

Also check out Mach1 rocketry. They have very good lightweight smaller kits.