Overbuilding

Pat_B said:

I cringe when I see articles like the one in SR because it's totally unecessary. How far off do you need to be on your motor choice so as to worry so much about a zipper that you have to glass a tube on a small model rocket?

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Not only that, but the Kevlar will still zipper a fiberglassed tube quite nicely. I've seen thin Kevlar cut halfway through a G10 fin root before finally breaking.

As an aside, I'm building a kit for my L1 cert and find it astonishing how many times epoxy is recommended all over the place when yellow glue is still stronger than the materials it bonds. Heck, if yellow glue can be used to build furniture that people sit on then it sure in the heck can easily handle 40-50 lbs of thrust from a rocket.

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We used Titebond II to hold a rocket together than flew on a Q motor.

A quality wood glue is amazing stuff, and I use it on anything that's going to fly on an H or I, unless the materials won't allow it.

-Kevin

I have read the article on the bulletproof Guardian and find it some what humorous. Build it bulletproof/heavy, lose 45% flight performance and use plastic chutes that melt and shred.

I agree with the build it to fly and recover properly rather than crash. I can see why this guy needs to over build. He needs to focus more on his recovery techniques.

For those that do not recieve Sport Rocketry here are the flight stats:

I haven't read the article but could this be ment as a tutorial? Fiberglassing Rockets 101? I mean, seems to me you could perfect methods in small scale before applying epoxy to that LOC Magnum your beefing up for your third level rocket


....that's "your" in the third person. Not specifically anyone.

dave carver said:

I haven't read the article but could this be ment as a tutorial? Fiberglassing Rockets 101? I mean, seems to me you could perfect methods in small scale before applying epoxy to that LOC Magnum your beefing up for your third level rocket


....that's "your" in the third person. Not specifically anyone.

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He's an L3 certified flyer that went thru 4 Guardians and got fed up with constant repairs to his favorite rocket. To each his own, nothing wrong with what he did. I found it odd that one would "beef up" a rocket like this and then use plastic chutes for recovery.

3 out of 5 flights with recovery failures is not a good record, needs attention.

rcktnut said:

I agree with the build it to fly and recover properly rather than crash. I can see why this guy needs to over build. He needs to focus more on his recovery techniques.

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You just described a significant portion of the hobby.

-Kevin

rcktnut said:

. He needs to focus more on his recovery techniques.

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Exactly. When I have a rocket in the design stage, as soon as everything is planned, I could spend days on end making sure my recovery system is going to work.

Sure, nobody enjoys losing a rocket due to recovery failure. That's why you design a system that will work, to some degree, without question.

Overbuilding is one thing, I overbuild, in the sense that I make sue everything is exactly how I want it. I probably work too much on the fillets, among other things. I overbuild to make sure it stays together in flight, but not like this. This is turning a fun little rocket into a ballistic death machine. :roll:

Problems (and various failure modes) with model rockets seems to happen to a large number of people. I kinda wonder if the four Guardian failures are related to something else I have seen a lot of: many people do not seem to understand how to select motors.

I have run into a disturbingly high number of people who think that the last digit of the motor designation indicates how "powerful" the motor is. Apparently they think the first few letters and numbers are just there for fun. They think that a "7" motor is "bigger" than a "3" or a "4" motor.

If this is what we are dealing with, there are several possible failure causes (and not even including user stupidity). There are tons of educational materials out there on the internet that do a great job of explaining Rocketry 101, but you just can't force some people to actually read them. Four failures (problems with safe deployment, motor/delay selection, construction, shock cord length, whatever) with ANY model rocket design should cause a normal person to review "the basics" for their answers.

I will not say that fiberglass has absolutely no place in low-power model rocketry, but I can't think of a single legitimate one. IMHO, the SR article author needs to go back to school, and needs some supervision to ensure that he learns the proper lessons this time.

If this sounds harsh, I guess it is. But if you can't make a freakin' MODEL ROCKET work properly, you have absolutely no business making it even more dangerous by inappropriate use of reinforcing materials.

Agreed. I have great success with the low power rockets, and usually, the only time I reinforce them at all is if I want to put in more powerful motors than the manufacturer recommended. Even then, minimal reinforcement is often adequate, and I've never seen a need for anywhere near the level described in the article.

After reading this article twice to be sure I wasn't misunderstanding what this guy was trying to accomplish. I'm more dismayed that our Model Rocketry Mag would publish such a trash article.

As many have mentioned just about everything this guy is saying is pretty much bunk, moreover the failure modes sighted are also easily prevented by proper adhesive choices and more attention to recovery system installation and packing. About the only thing in the entire article that was really of any value is altering the length and makeup of the chockcord and anchor system tho i'd not do it the way shown either.

I'm planning on posting a letter to the editor of Sport rocketry asking what on earth he was thinking letting such an outragiouly ill advised article be given the prestiage of being published in what used to be a good mag offering sound techniques and tips to the hobby flying community. Seems the quality of submissions has fallen considerably. What a complete farce.

powderburner said:

I will not say that fiberglass has absolutely no place in low-power model rocketry, but I can't think of a single legitimate one.

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Here's one example. There are others. In this case, a bit of glass is well suited for attaching an external motor hook. Another example is using some light glass in lieu of gauze on a Scout clone (motor hook, fin roots). In both cases, the glass/epoxy can be made stronger and lighter than using glue/gauze. And it's much easier to apply a finish over.


I don't advocate overbuilding, and in fact often find myself critical of it. I get frustrated that many users want to glass over something merely for the sake of glassing, and not because it's necessary. That is, because they saw somebody else do it, so they wanted to try it. That's behaving faddishly rather than scientifically.

That said, the world of HPR has brought us many techniques which I borrow from whenever it makes sense. Besides using small amounts of glass in model rockets, I use - when applicable - nylon chutes, motor retention with screws/nuts, and recovery harnesses incorporating kevlar and nomex, to name a few.

Anyway, I hope we're all nice when we're admonishing fliers for over-building - we don't want to chase them off.

Doug

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plano-doug said:

Here's one example. There are others. In this case, a bit of glass is well suited for attaching an external motor hook. Another example is using some light glass in lieu of gauze on a Scout clone (motor hook, fin roots). In both cases, the glass/epoxy can be made stronger and lighter than using glue/gauze. And it's much easier to apply a finish over.

I don't advocate overbuilding, and in fact often find myself critical of it. I get frustrated that many users want to glass over something merely for the sake of glassing, and not because it's necessary. That is, because they saw somebody else do it, so they wanted to try it. That's behaving faddishly rather than scientifically.

That said, the world of HPR has brought us many techniques which I borrow from whenever it makes sense. Besides using small amounts of glass in model rockets, I use - when applicable - nylon chutes, motor retention with screws/nuts, and recovery harnesses incorporating kevlar and nomex, to name a few.

Anyway, I hope we're all nice when we're admonishing fliers for over-building - we don't want to chase them off.

Doug

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While your light glass example is a good one. its not new nor a technique borrowed from HPR. Model Rocketry has used .5oz and .75oz glass and epoxy for decades before HPR was ever thought about.
As a matter of fact everything listed; Nylon chutes, motor retainer hardware, small brass, Stainless steel and nylon hardware and recovery systems incorporating Kevlar, Nomex and other exotic flame retardant materials were put to use in the hobby as soon as they hit the market. I've personally been using the motor mount Kevlar/elastic and Stainless leader/kevlar/elastic shockcord anchor systems since the mid-70's. Ain't no part of these things HPR derived. Over-built to the point of absurdity by HPR builders...you bet, but not a single innovation i've ever seen that wasn't already a known "technique" In the hobby long before there was a motor larger then D. I'm sure they've altered things to the point they are no longer reconized by model rocket standards but come on... Shoot we were flying Hybreds in the late 60's....Ain't nothing different but the size. Now as the next generation is entering the hobby some want to make it look like doing this stuff to Models somehow makes them better... IT DOES NOT. it makes them more of a danger to the very people we're telling that this is the SAFEST outdoor hobby there is period.
BulletProof building is counter productive to the Good of the HOBBY. We should be building to absorb kinetic energe not expell or transfer it. Just like Cars are beginning to build in crumple zones our models are INTENDED TO "Do As little harm as possible also. Build for the Flights not the CRASH. make um the Lightest, best performing models possible.

plano-doug said:

Here's one example. There are others. In this case, a bit of glass is well suited for attaching an external motor hook.

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Yes, I understand, it makes a solid MMT/clip. Myself, I woulda used a scrap of cardboard BT outerwrap and white glue, but fiberglass does work in this case.

plano-doug said:

I hope we're all nice when we're admonishing fliers for over-building - we don't want to chase them off.

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I don't try to be mean (it just comes naturally?) but I cannot simply let these silly over-builds go by without at least commenting. And yes, I do want to chase them off; I do not want these guys associated with our hobby. If enough people build that way, sooner or later one of these over-builds will hit someone and cause serious injury, and then the insurance companies will accomplish what our government has been trying to do (shut our hobby down).

This stuff does not belong in low-power rocketry, and I will go ahead and post the opinion that 90% of the over-builds in high-power rocketry are not necessary either.

powderburner said:

This stuff does not belong in low-power rocketry, and I will go ahead and post the opinion that 90% of the over-builds in high-power rocketry are not necessary either.

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I think "doesn't belong" is a bit strong. "Is unnecessary" is a better phrase, I think.

And you're correct about it in HPR.

"Back in the day," people used to fly M motors with nothing more than cardboard tubes. Now, many are convinced that you need 5 layers of fiberglass or 3 layers of carbon fiber to fly an M motor.

-Kevin

Guys I have to confess.....on my first MMX build (bic pen rocket) I used JB weld thoughout (well wood glie doesn't work on plastic, nor CyA so I have a case) and I added epoxy fillets :Y

Perfect example of a legitimate need---bonding special materials

And I know there are other cases. If I was trying to build a high-powered scale model of a Russian AA-10 Alamo, no way would I build those reverse-tapered fins without a bujillion layers of fiberglass across the roots (cardboard and balsa and wood glue just ain't gonna do it)...well, maybe half a bujillion

powderburner said:

Perfect example of a legitimate need---bonding special materials

And I know there are other cases. If I was trying to build a high-powered scale model of a Russian AA-10 Alamo, no way would I build those reverse-tapered fins without a bujillion layers of fiberglass across the roots (cardboard and balsa and wood glue just ain't gonna do it)...well, maybe half a bujillion

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Erm..... using JB weld for everything on that build..... But JB Weld was the closest epoxy in my reach, and epoxy clay was really hard to apply so I gave up on that.....But in general JB weld in MMX-MPR is a No-no

Use of pretty nearly anything is not allowed

ScrapDaddy said:

JB weld in MMX-MPR is a No-no

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Hey, you have to use some kind of adhesive (that works) on those materials (you did use less than four pkgs of JB, didn't you?)

powderburner said:

Use of pretty nearly anything is not allowed



Hey, you have to use some kind of adhesive (that works) on those materials (you did use less than four pkgs of JB, didn't you?)

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I tried using craft CyA with no luck so I got desprete and JB weld just popes on my head I used a dab of JB for the whole thing

PS useing the pen cap makes great fillets and a great boattail

While Mr. Shaw certainly went overboard with his Guardian, most of his approach is not fundamentally flawed. The only true mistake he makes is putting all that fiberglass on.

There's nothing wrong with his shock cord mount; it's pretty similar to Quest mounts. I wouldn't have used braided kevlar, but having a slightly extra-strong shock cord is not horrific. Likewise, I wouldn't use epoxy on a LPR MMT, but to each his own. He also trims the retention hook - absolutely necessary for 18/20 D motors.

The upper section uses nylon bolts to attach the forward body tube - which is reasonable because he uses it as a payload bay. He also gave the entire inside of the body tube a coating of thin epoxy for protection, which is perfectly fine. I would likely make some or all of those modifications myself if I aquired a Guardian.

The problem is that he used 3 wraps of 2 oz fiberglass. That sounds more like what you'd use on a L2 or L3 rocket. If he has problems with the body tube crimping, or the fins breaking, then he should be more careful with selection of delays and make better fillets. He states that deployment was at -35.7 fps with a C6-5... that indicates that a C6-3 would have been much closer to apogee deploy.

I'm also confused that he didn't use a kevlar chute protector and upgrade to a nylon chute. Those are the first things I put in any Estes rocket that I want to survive more than 3 flights.

plano-doug said:

I don't advocate overbuilding, and in fact often find myself critical of it. I get frustrated that many users want to glass over something merely for the sake of glassing, and not because it's necessary. That is, because they saw somebody else do it, so they wanted to try it. That's behaving faddishly rather than scientifically.

That said, the world of HPR has brought us many techniques which I borrow from whenever it makes sense. Besides using small amounts of glass in model rockets, I use - when applicable - nylon chutes, motor retention with screws/nuts, and recovery harnesses incorporating kevlar and nomex, to name a few.

Anyway, I hope we're all nice when we're admonishing fliers for over-building - we don't want to chase them off.

Doug

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In 2 ½ years of BARdom I have launched 800+ flights of all E’s and under. No epoxy, no glass, no basswood, no baffles, no nylon chutes, no Nomex heat shields, no catos, no tri-fold failures, no zippers, and until last week and the Leduc, no rockets retired or never to fly again due to unrepairable damage. I have always built kits per the directions and only with the materials supplied. Just plain boring whoosh pop and valuerocket.com Es kind of stuff.

Where is low power nation around here? I fly with mostly Mid and High power guys who constantly admonish my no modification - low power ways. They are downright mean and heartless in their criticism of my lack of ruggedizing, especially on my Launch Pad kits. When viewing my flights for the first time they always ask what kind of wadding I used as my birds blow chunks at apogee. “Unadulterated Dog Barf” I reply, “the other stuff is just too expensive.” They just look down, shake their heads and walk away. I am proud of the fact I have used nearly one half of my $9 bail of Dog Barf, having given away multiple freezer bags full and used some in my house, I estimate I have about 3 years left. They simply can’t stand the Launch Pad method of using 10” of nylon string to hold the nose cone, especially after I tell them that any one desperate enough to fly with such thin tubes and balsa on an F is just hanging on by a thread anyway. After several successful flights with the clustered Scimitar I turned to them with a cold and maliced heart and said “1/16 squishy balsa fins laminated with label paper…the ultimate Mid Power building material.” They just looked down, shook their heads and walked away. But what goes around comes around and after bragging up Launch Pad recovery methods I made the mistake of using a little too much CA in reinforcing the nylon string to the nose cone and snap swivel, resulting in a brittle and breakable situation. “Just a flesh wound” I said, “I’ve had worse.”

But don’t get me wrong, I really like flying with them because of the excitement they generate with their flights. I’d say they have about a 33% failure rate as something always seems to go wrong. It is just like watching NASCAR for the wrecks. I love to see the piston go wrong on the PML kit and watch it do about a two foot dead cat bounce on the soft Prairie Dirt, but at least it comes back virtually undamaged. All the reload Catos, funky delays, blow bys and blow outs are particularly exciting. The crushed tubes, nosecones, burned and ripped recovery harnesses sometimes will remind me of Dunkirk in the spring of ’40. Even with the best computer simulation programs those rugged, modified and heavy kits have a nasty habit of being a little on the unstable side. But higher, faster and stronger is the fad and it is really cool.

It is hard to keep the low power faith in our high power world. The youngster’s just laugh when you tell them that mighty D powered motors are for experienced builders only – why it says so right in the old catalog. My stock Guardian has flown a dozen times with out a scratch, but now, in the name of coolness and the article, I am going to use a D21 with a thin mil dry cleaner bag parachute using fishing line shroud lines and just a couple sheets of real wadding. I'm OK on the simulation program so science is served. This is going to be wicked cool!
:bangbang:

Just a note here: He did launch at a club field (NOVAAR's Great Meadow) I assume it was a HPR field. It would be the proper field for a rocket like that. I guess as long as a rocket like that isn't launched in a park or school grounds if he wishes to build them like that, so be it.

Regardless I still think some other items need to be addressed, ones that would produce more successful flights.

rcktnut said:

He's an L3 certified flyer that went thru 4 Guardians and got fed up with constant repairs to his favorite rocket. To each his own, nothing wrong with what he did. I found it odd that one would "beef up" a rocket like this and then use plastic chutes for recovery.

3 out of 5 flights with recovery failures is not a good record, needs attention.

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Ok... lemme see if I got this straight...

The writer of the article is L3 certified, but has had four Guardians zipper/ core sample/ re-kit/ broom recover (or whatever other cute misnomer you want to hang on it) and so his solution is to fiberglass the whole thing...

Geez, ever think of getting a nylon chute?? Sim the thing to choose a better motor?? Fly in better conditions maybe?? This just seems like TOTALLY putting the horse before the cart...

It DOES reinforce my opinion of the 'certification' process-- it's more hoop jumping feel good baloney than any REAL determination of capability, skill, correct mindset, knowledge and understanding, experience, etc...

I've seen much the same in my profession-- agriculture. A decade or so ago, the gov't decided it would be a wonderful idea if all farmers had to get a license to use certain farm chemicals on their crops. Basically it was just a reason to collect $50 from every farmer in the country, and create a bureaucracy to keep a lot of gov't types employed, and generate bigger crowds for the ag extension service meetings to justify their existence (and budget) since the farmers would have to get "continuing education units" to renew their licenses, so they had to attend extension meetings and field days to get the hours and certificates.

Anyway, I go by a bigshot farmer I know fairly locally (who used to be a big seed dealer before he went broke) to inquire about buying about 2 1/2 gallons or so of Methyl Parathion-- apparently some crooked exterminators in Mississippi decided that instead of spraying methyl parathion in houses for roaches that had the EPA certification label for domestic use by exterminators (and therefore was twice the price) they'd just use the cheaper cotton poison EPA labeled methyl parathion (exact same stuff, just LABELED BY THE GOVERNMENT DIFFERENTLY, and priced cheaper because farmers use TONS of the stuff) and in so doing, violated federal law (because of the EPA labelling differences) and EPA came down on the offenders like a ton of bricks. SO, the company that makes methyl parathion settled with EPA and agreed not to sell the chemical in gallon or 2 1/2 gallon jugs anymore-- only in 40 gallon minibulks or above, which require a special pump (and a couple thousand acres to spray it out on). Since I wouldn't use 40 gallons in 5 years, I just wanted to buy a little from the bigshot to spray one field of soybeans getting eaten by stinkbugs.

Now, this bigshot farmer, he sits on the county committee, overseeing the pesticide license tests, renewals, record checks, testing, certification, etc. and I pull up in his yard and get out of the truck. He pulls in from the field in his new rented air conditioned CD player equipped Hi-Boy sprayer and parks on the slab in front of my truck. He climbs down, reaches under the tank, and removes the drain bung... letting the last 10 gallons of cotton poison spray run out on the concrete, pool, run across the concrete and out into the grass, 15 feet from his water well! I'm standing there in shock, picking my jaw up off the floor in shock and amazement at this brazen display of stupidity, and befuddledly asking about buying some methyl parathion... his dog runs up and starts lapping up the cotton poison, so he interrupts me to chase the dog off from it... Turns out he had used all his up and didn't have any to sell, so I left, still shocked and amazed... Typically a farmer would make another pass or two to spray any leftover chemical out of the tanks before returning home, or if there's a bit left in the tank, pull the drain bung out in the field and let it dribble out in the field on the way back to the house... not dump it by his water well!!!

Just goes to show you how worthless all these licenses, inspections, certifications, and all this other hullaballoo is... if licenses were the answer, we wouldn't have drunk drivers or so many idiots on the road...

Also reinforces the fact that usually the biggest idiot in the country is the one charged with overseeing everyone else... OL JR

I'll admit to being disappointed at the attitude some folks are getting from HPR fliers.

Myself, I fly mostly HPR, but when I'm flying with my youngest, it's almost exclusively LPR -- he doesn't have the endurance, yet, to walk fields with me, recovering high power rockets. But he loves rockets, and he can fly LPR faster than I can prep them!

The folks I fly with like any rocket, regardless of size. AIRFest, a large annual launch in Kansas, typically lets kids fly for free, regardless of what they're flying.

-Kevin

TheAviator said:

I got the same reaction when I went to a certain club launch (the club will remain undisclosed, because I do like some of the members). I had a 3" rocket, so I was free from criticism (they never saw the construction techniques), but my girlfriend had her first rocket, a FlisKits Cougar 440 that I gave her, with her. They didn't even have the self control to stifle the sarcasm and laughter. I was genuinely hurt at the fact that they would laugh at someone simply because they didn't sink the big HPR bucks into the hobby.

They got their comeuppance though; the nearly out-of-sight flight on an A3-4T made their jaws drop.

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Geez, what rocks did you turn over to find those "people?" I have never encountered that attitude among HP fliers. Every one that I have ever spoken to or launched with has been really interested in and supportive of what I was flying, including Micromaxx. In fact, most fly LPR, too and there are even some Level 2 fliers in my club who participate in NAR contests. When I first resumed flying rockets, I heard stories about such encounters, but in the 6 years since then, I have never once encountered anyone with that attitude who was a serious rocket flier.

Oh, sure - I can well imagine that there are jerks who have never before been interested in rocketry but hear about HPR and go "wahoo!" They go out and buy a LOC or PML kit, build it and launch it maybe two or three times, all the while turning up their noses at people who fly "baby rockets" before moving on to more exciting pastimes, such as starting meth labs. There was even one such person in my club who joined around the same time that I did. He filled up our mailing list with posts in which he sneered at the idea of launching "baby rockets." That year, he attended exactly one club launch. The following year, he did not renew his membership, and we never heard from him again. Don't spend even one minute worrying about losers like that.

Mark K.

Daddyisabar said:

Where is low power nation around here? I fly with mostly Mid and High power guys who constantly admonish my no modification - low power ways. They are downright mean and heartless in their criticism of my lack of ruggedizing, especially on my Launch Pad kits.

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Really? I haven't seen that attitude at all. Rocketeers (both high and low power) seem to be great people for the most part, and almost every one I know will support people no matter what size rocket they are flying.

Daddyisabar said:

Where is low power nation around here?

But don’t get me wrong, I really like flying with them because of the excitement they generate with their flights.

But higher, faster and stronger is the fad and it is really cool.

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I am part of the low power nation, with just a little MPR (I have to confess I weakened and got my level 1 cert). I normally just fly my low power birds (over 100 rockets). With a few hundred flights between them all, I've lost a few, mostly to rocket eating trees.

I've never received any attitude about flying LPR. In fact, I generally get positive comments about my rockets (I tend to shun the 3fnc and go for scifi, fantasy, or oddroc).

But I also have to admit, I love to watch the big ones fly!

Charter member (1967) of the low power nation here, too.

(Back then there was no LPR, MPR, HPR. It was all just called "model rocketry.")

Mark K.

I as well Mark! Model Rocket builder flyer since 1965.

Shouldn't we all be writing letters to the editor demanding retraction and an explaination from Sport Rocketry based strictly on the UNSAFE issues raised by Bullet-Proof building?

All the discussion here is prefectly health but I think unless Sport Rocketry is made aware of their blunder they will go along blindly following the HPR stressed mandate that seems to be coming from NAR HQ?

Simply complaining about it here isn't gonna help much as the masses of Sport Rocketry young and Old readers are lulled into believing Over-Building of this sort is perfectly fine....SEE it says so right there in the national magazine.
It will not take long for someone to be seriously injured or killed by one of the things...which are NO LONGER model rockets.... they have become lethal projectiles.

WOW!

I read the article in question and thought "WHY?" I did chuckle at the end of the article when the author reported a separated fin.

Other than recovery issues, shouldn't Sport Rocketry be publishing an article on ROCKET REPAIR? A dying art, I know, but a great skill to have.

And, YES, we should be writing the NAR about this article.

Lastly, I AM LOW POWER! 100%. The largest motor I have ever burned was an Aerotech "E"... In a Viking (all I got back was the body tube).

Okay, I think referring to them as "lethal projectiles" is overreacting a bit.

Regardless, folks are obviously upset about the article. Why doesn't someone write a counter-point article, that has some references back to the original, and provides alternative solutions?

"In a previous issue of Sport Rocketry, and article was printed which recommended fiberglassing, etc. Rather than trying to build a bullet-proof rocket, I thought I'd demonstrate some alternative techniques to help address the same issues as the previous author."

Then, go on to make appropriate recommendations and show the various techniques.

-Kevin