Does anyone ground test their rockets?

SpaceManMat said:

You should probably try AreoFinSim the fins are the most likely to fail. Other than that I think you are looking at using a FEA application of some sort. BTW it looks like AreoFinSim is now free https://www.aerorocket.com/finsim.html

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Thanks for the linky SMM. Interesting read; John Cipolla sounds like the real Zefram Cochran.

DizWolf said:

Typically, most people just build rockets much stronger than they need to be.

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Yes, that appears to be the case. Hence my question. As a child I was content with this approach as an adult, not so much.

cwbullet said:

I ground test if they are over 20 lbs

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The whole rocket or certain components?

jahall4 said:

Yes, that appears to be the case. Hence my question. As a child I was content with this approach as an adult, not so much.

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Well jahall4, I guess some (most ?) posters (myself included) might fall under the category of "seat of the pants" rocket engineers. Have you tried a forum search on "structural analysis" ? Some guys are actually applying a little more math and science to the proceedings.

SpaceManMat said:

You should probably try AreoFinSim the fins are the most likely to fail.

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But where would I get some of the inputs that are coefficients?

jahall4 said:

But where would I get some of the inputs that are coefficients?

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Don't know how to use it, only just found out it was being offered for free so grabbed a copy. It's pretty technical stuff and I've got some ways to go before I'll need to use it, hopefully I'll know how to use it by then.

jahall4 said:

But where would I get some of the inputs that are coefficients?

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What exactly are you wanting to build?
Size [length & diameter]
What size motor do you want to fly?

What is your goal....speed, altitude,payload, something else?

This will determine how to build it.
Strength of materials, will determine what to build with.


I have not ground tested the rocket per se. I have tested the various components or looked up testing. Crush testing of tubes both vertically [compression] or horizontally [hoop] Fin materials for flex [flutter strength].

One can find a decent survivable material for just about any design, though the upper limits require large/deep pockets.

So.....what are you trying to build? You must determine that first.

Your posting under Mid-Power so it should not be that difficult.

No need to reinvent the wheel, unless you are looking for something very specific. Widely available materials are known to be sufficient for almost everyone's purposes without a bunch of hoopla.

10fttall said:

No need to reinvent the wheel, unless you are looking for something very specific. Widely available materials are known to be sufficient for almost everyone's purposes without a bunch of hoopla.

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Are you really suggesting rockets can't be built stronger, lighter, faster, .... safer, than they are currently?

blackjack2564 said:

Crush testing of tubes both vertically [compression] or horizontally [hoop]

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I have partnered successfully with USPS, FedEx and UPS to perform these tests. Every box that arrives at the house is another valuable data point!

Post of the day. Right there.

jahall4 said:

Are you really suggesting rockets can't be built stronger, lighter, faster, .... safer, than they are currently?

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OK, I give up. Have you invented or applied a new material, or found a new construction technique, or discovered some new physics that would lead you to believe that you can build stronger, faster, lighter than other hobbyists? If so, please share.

Are you really suggesting rockets can't be built stronger, lighter, faster, .... safer, than they are currently?

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No, I said not one word of that. The question was does anyone ground test. My answer for me is, that I am very satisfied with the range of materials and products available that are WELL proven. It is an extremely small sub-set of our hobby that would require any ground testing of rockets, other than properly sizing ejection charges. My rockets turn out plenty strong, plenty fast, and light enough to be recovered safely. What else could I want, except for a bigger field?

jahall4 said:

Originally Posted by blackjack2564
Grab the nose cone with rocket in vertical position. Pick it up holding the NC only and shake a bit. The NC should be snug and barely begin to move.
If it comes right off, I put a wrap or so of tape on the shoulder to snug it up.Sounds reasonable, anyone else do this?

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I do it a few times before and during the build and then finally on the field just before flight - weather/temp conditions can mess with fittings.

10fttall said:

No, I said not one word of that. The question was does anyone ground test. My answer for me is, that I am very satisfied with the range of materials and products available that are WELL proven. It is an extremely small sub-set of our hobby that would require any ground testing of rockets, other than properly sizing ejection charges. My rockets turn out plenty strong, plenty fast, and light enough to be recovered safely. What else could I want, except for a bigger field?

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Quick question and be honest... Which do you like better A) Building Rockets or B) Flying Rockets?

10fttall said:

No, I said not one word of that.

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Yes you did, and you are saying it again...

10fttall said:

My rockets turn out plenty strong, plenty fast, and light enough to be recovered safely.

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What does "plenty" mean? and when is weight only about safety in recovery?

Dude...really?

None of what I said says that rockets can't be built stronger, faster and lighter. Saying they can't is obviously foolish. Of course they can. What I actually said, if you drill down the meaning beyond my plain language is, that I DON'T GROUND TEST BECAUSE I DON'T NEED TO. I don't care to, I don't have time to, and I don't have a desire to make a mini-Thiokol plant in my backyard. What I have available is sufficient, and then some. By the way, "Plenty" means "Ample." And I don't launch from a desert, so I couldn't possibly care any less if my rocket was lighter. Thank you for your concern though.

10fttall said:

Dude...really?

None of what I said says that rockets can't be built stronger, faster and lighter. Saying they can't is obviously foolish. Of course they can. What I actually said, if you drill down the meaning beyond my plain language is, that I DON'T GROUND TEST BECAUSE I DON'T NEED TO. I don't care to, I don't have time to, and I don't have a desire to make a mini-Thiokol plant in my backyard. What I have available is sufficient, and then some. By the way, "Plenty" means "Ample." And I don't launch from a desert, so I couldn't possibly care any less if my rocket was lighter. Thank you for your concern though.

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You're obviously taking this way to personal and on the defensive. I'm confident I'm not the only one who tries to build a "better" rocket every time (at the risk of using another generalization like "plenty" and "ample). If you like flying rockets more that building that's OK. Personally I like building rockets more than flying and I love flying it just seems pointless to me personally to build the same rocket with the same techniques (and materials in some cases) hence why I thought testing, ground testing in some cases, could have some benefits.

You're obviously taking this way to personal and on the defensive.

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Well, you did try to tell me what I meant, after I clearly answered the original question.

I'm confident I'm not the only one who tries to build a "better" rocket every time (at the risk of using another generalization like "plenty" and "ample). If you like flying rockets more that building that's OK. Personally I like building rockets more than flying and I love flying it just seems pointless to me personally to build the same rocket with the same techniques (and materials in some cases) hence why I thought testing, ground testing in some cases, could have some benefits.

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It's hard to say that I like building or flying more. I like the process. I like the results. I don't want someone to build a rocket for me. I design, upscale, downscale, original, etc. Then later, I launch something that gives a safe, visually challenging, and sometimes achievement-oriented flight (like eggs, cameras, altimeter) Had I not designed and built the rocket, the results would not be nearly as rewarding. You can test whatever you want to test, and it may have some benefit, if the kind of benefit that results is what you're after. It's not what I'm after, and that was the original question.

If that is what you really meant then why didn't you just say that in the first place instead of saying:

10fttall said:

No need to reinvent the wheel, unless you are looking for something very specific. Widely available materials are known to be sufficient for almost everyone's purposes without a bunch of hoopla.

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Which suggests what others are "after" is not worth the chase, "reinvent the wheel" and "hoopla" convey a dismissive almost belittling opinion.

The question was, Does anyone ground test..." I was answering for me.. Although like I said, the proven materials meet most everyone's needs. I think you'll find that's a fact. If it doesn't apply to you, it doesn't apply to you.

Alot of original research was done by Drake "Doc" Dameräu on the rocketmaterials page: https://rocketmaterials.org/index.html

I'm afraid this is a web orphan site now but some useful data can still be found there IMO. I'll say again that I think a few targeted searches of this forum will find some posters who share your research and analysis bent, jahall4.