cool rocket with gyro to prevent spinning

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jflis

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oh, now *that's* impressive! (not *new*, but impressive none the less). This would make a great R&D project for NARAM, in my opinion.

would make a great product too.
 

DynaSoar

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Originally posted by jflis
oh, now *that's* impressive! (not *new*, but impressive none the less). This would make a great R&D project for NARAM, in my opinion.

would make a great product too.
Hobbico sells a piezo gyro that weighs half an ounce and fits in a 29mm tube.

Lest the point be missed: this is an example of active guidance which some people still wrongly insist is against some rule or other. Anyone attempting this, which I would encourage, can expect to have to face incorrect criticism.
 

Mad Rocketeer

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This isn't against any rules I ever heard of, except maybe some thumb rules about how to make stuff stable. Active guidance is dang hard to get right, so there's a lot of advice out there against it. That's no reason, IMHO, not to work on it though (on a "heads-up", checking your stability before flying it around non-participants, away from the crowd basis). Who knows? If enough effort is put into it, the avionics packages that go into expensive rockets may one day do far more than dual-ejection and locator signals to ensure the safe, reliable, and convenient recovery of rockets.

Did your rocket weathercock into a sudden gust of wind? How about if it could actively return to vertical under boost? What if it could even nudge itself back downrange a bit? What if it could home in on a beacon at the pad during a glide or parasail recovery? The possibilities are endless and exciting ! :D :D :D
 

Stymye

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guidance only comes under scrutiny if the rocket is capable of being activly guided tword a target..keeping a rocket straight or from spinning is simply a stability system
 

DynaSoar

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Originally posted by Mad Rocketeer
This isn't against any rules I ever heard of, except maybe some thumb rules about how to make stuff stable. Active guidance is dang hard to get right, so there's a lot of advice out there against it.
Some people insist it's specifically against rules, and sometimes quote one rule set or another, but upon checking no such rule exists. Confronted with this, they then insist that although it may not be against the rules, nobody should do it because it could be used in a weapon, and if we started doing this then The Government Will Come Down On Us Harder Than They Already Have. There's clearly a problem with logic and rationality when it comes to the subject, and it has little to do with the safety factor of an actively guided rocket. (Which is itself a non-issue if the rocket fails safe, that is it acts like it had no guidance if the guidance fails and flies like a normal rocket).



That's no reason, IMHO, not to work on it though (on a "heads-up", checking your stability before flying it around non-participants, away from the crowd basis). Who knows? If enough effort is put into it, the avionics packages that go into expensive rockets may one day do far more than dual-ejection and locator signals to ensure the safe, reliable, and convenient recovery of rockets.

Did your rocket weathercock into a sudden gust of wind? How about if it could actively return to vertical under boost? What if it could even nudge itself back downrange a bit? What if it could home in on a beacon at the pad during a glide or parasail recovery?
Would you get more altitude if you worked against weathercocking, or would you take a power hit fighting the wind and actually lose altitude? Weathercocking can ge a good thing; you want apogee upwind if you're going to drift downwind. Just working out a guided acsent and normal unguided descent to a spot landing would make for an entire contest category worth of flying.

Many rocket drag races/simultaneous launches make very visible just how erratic our ascent paths are. Now image several identical birds with similar control systems, programmed to fly straight up during boost, but arc over away from each other during coast/smoke. Rocketry aerobatics. Watch any video of the Thunderbirds, Blue Angels, Snow Birds (eh?) or Red Arrows (blimey!) for more ideas.
 

Stymye

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guided model rockets are of no concern to the various agencys
but

but there ARE regulations concerning guided or guidance supplimented rockets on the Faa site
also reffer to the Faa site concerning Unguided suborbital launch vehicles
also look up the faa regulations concerning UAV's (unmanned aerial vehicles) the larger rockets we fly, if activly guided would easily fall into any of those categorys,, if you want to get technical

the DOD also consideres a "guided" rocket a "Derelict Airborne Object" if it falls into this category- and I quote directly

"Any rocket, except aerial firework displays and model
rockets, using not more than 4 ounces of a slow burning-propellant
made of paper, wood, or breakable plastic containing no substantial
parts weighing more than 16 ounces, including the propellant"

this category also includes moored balloons and kites with payloads among other things even if flown from private property

I'm not making this up , honest
 

Stymye

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I like the idea of guidance in model rockets,,,and would like to have a go at it myself somewhere in the near future.
so I have been reasearching it myself


here are some links and personell sites to some of the regs I mentioned

https://www.seanet.com/~ssstolt/regs/faaregs.htm

https://web.archive.org/web/20020601105902/https://ast.faa.gov/contest/sag_uslv.htm

you can get the referenced DOD PDF from this page
https://www.wanttoknow.info/010601dod

most of what I have is downloaded on pdf files from Faa
I'll find and post them too
 

DynaSoar

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Originally posted by stymye
the DOD also consideres a "guided" rocket a "Derelict Airborne Object" if it falls into this category- and I quote directly
No it doesn't. A derelict airborne object is one that has been abandon to trajectory or simply ballistic. it means it has been launched, whether with a target in mind or not. and is now flying free without control, whether the control was lost or abondoned.

They have this definition so that they can consider an abject to be derelict and to be destroyed even if it is actually controlled, IF they can't prove it is controlled by gaining control of it. It is easier to get permission to shoot it down if it's considered abandon than if it's acting as if it belongs to somebody but they don't know who. This makes anti-terrorism reaction faster and to require less permissions, which is the whole point of that DoD article.

Among the objects this can happen to is a previously guided rocket. That does not mean a rocket is by definition a detrelict object. If it were, everything we launched, being ballistic, would could get shot down.

"Any rocket, except aerial firework displays and model
rockets, using not more than 4 ounces of a slow burning-propellant
made of paper, wood, or breakable plastic containing no substantial
parts weighing more than 16 ounces, including the propellant"

this category also includes moored balloons and kites with payloads among other things even if flown from private property

I'm not making this up , honest
I don't think you are. But I'm pretty sure you're misreading some of it.

What they are saying is that if an object fits the definiton of model rocket (< 1 lbs, < 4 oz. propellant), it is considered to be no threat and so will not be considered a derelict object worth considering destroying.
 

DynaSoar

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Originally posted by stymye
I like the idea of guidance in model rockets,,,and would like to have a go at it myself somewhere in the near future.
so I have been reasearching it myself


here are some links and personell sites to some of the regs I mentioned

https://www.seanet.com/~ssstolt/regs/faaregs.htm

https://web.archive.org/web/20020601105902/https://ast.faa.gov/contest/sag_uslv.htm

you can get the referenced DOD PDF from this page
https://www.wanttoknow.info/010601dod

most of what I have is downloaded on pdf files from Faa
I'll find and post them too
As far as I can tell, guidance comes into question only as the definition of an "unguided suborbital launch vehicle" versus "expendable lauch vehicle" which is guided. They are considered differently.

I do not see where these apply to the lesser level, amateur rockets, with a burn time of less than 15 seconds (unless launched at a TRA EX launch where 60 seconds is the limit) or if they carry a total of less than 890,000 Newton-seconds. (The M5 motor used in the Nike booster had 785,500 newton-seconds.) USLV or ELV come into play only when the vehicle exceeds these burn time or impulse limits.
 

Mad Rocketeer

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Originally posted by DynaSoar
Some people insist it's specifically against rules, and sometimes quote one rule set or another, but upon checking no such rule exists. Confronted with this, they then insist that although it may not be against the rules, nobody should do it because it could be used in a weapon, and if we started doing this then The Government Will Come Down On Us Harder Than They Already Have. There's clearly a problem with logic and rationality when it comes to the subject, and it has little to do with the safety factor of an actively guided rocket. (Which is itself a non-issue if the rocket fails safe, that is it acts like it had no guidance if the guidance fails and flies like a normal rocket).
I don't think this fail-safe (though perhaps the best that could be done under those circumstances) would be enough to ensure that an actively guided rocket would always be at least as safe as an unguided one. The guidance system might not "know" it had failed, for one thing. Also, if a failure has caused a dangerous trajectory, flipping the trim tabs to neutral and continuing on course could be a bad thing. If I were doing this, I'd have a passive/active system, where the effect of the fins was mostly a passive one, with active trimming for finer control.

Originally posted by DynaSoar
Would you get more altitude if you worked against weathercocking, or would you take a power hit fighting the wind and actually lose altitude? Weathercocking can ge a good thing; you want apogee upwind if you're going to drift downwind. Just working out a guided acsent and normal unguided descent to a spot landing would make for an entire contest category worth of flying.
I was thinking more in terms of sudden but short gusts, rather than a steady wind from one direction. With a steady wind, you want it to fly upwind and fload back downwind. With a sudden short gust, the rocket can tip, fly way over yonder, and land vertically into the woods or back yards or highway that it ended up above at the end of boost.

On the altitude question, I'd surmise that it depends on the degree of weathercocking. If it tips just a bit, then it'll fly higher if left more streamlined. If it tips way over, it's no longer climbing much unless it's tipped back toward vertical.

I thought of the new event possibilities too. Either ascent or descent or both could be guided, with separate categories for each, like they have for boost gliders vs. rocket gliders.

Originally posted by DynaSoar
Many rocket drag races/simultaneous launches make very visible just how erratic our ascent paths are. Now image several identical birds with similar control systems, programmed to fly straight up during boost, but arc over away from each other during coast/smoke. Rocketry aerobatics. Watch any video of the Thunderbirds, Blue Angels, Snow Birds (eh?) or Red Arrows (blimey!) for more ideas.
At my last launch, a friend took some digital video of a three-way drag race (the first and only drag race I ever did so far). His scratch-built wiggled all the way up but took off like a scalded cat. My Big Bertha went up "like a train pulling out of the station" (in his words), straight up and very stable. My Micro-Maxx plastic brick went up, tipped, flew "over there" somewhere, and we didn't find it. I figured out that day that with multiple launches you want a set of dedicated eyes on each bird.

My 150th post. Woo Hoo! :D
 

Ozymandias

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Although it's not a new idea, I think guided rockets are very cool. If I recall correctly, there was an article in HPR a couple years back about making simple rollerons like the ones on the Sidewinder missile. The helicopter gyro method seems to work well too as long as you have servos fast enough. I'd really like to try it on a future rocket.
 

Lugnut

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Just thinking outside the box for a cheap way to do this. Would 3 Mercury switches (x,y,z orientation) in curved tubes integrated into an RC receiver be feasible?

Lug
 

DynaSoar

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Originally posted by Lugnut
Just thinking outside the box for a cheap way to do this. Would 3 Mercury switches (x,y,z orientation) in curved tubes integrated into an RC receiver be feasible?

Lug
Not really. They'd be too susceptible to vibration. Too much shake and the mercury would splatter around inside the bulbs and make spurious contact.

That's not to say some simple mechanical equivalent couldn't work. A 2 degrees pendulum might work for vertical flight if it were damped properly. Without damping (which is the problem with mercury switches) you can get into a feedback loop and oscillate out of control as well as get false activiations.

How about....

curved tubes with a viscous and colored oil in them, and a bubble of air, like in a level. You could track the bubble in the tubes with LEDs and photodetectors, shining through the bubble or blocked by the oil.
 

rocketsonly

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Originally posted by DynaSoar
Not really. They'd be too susceptible to vibration. Too much shake and the mercury would splatter around inside the bulbs and make spurious contact.

That's not to say some simple mechanical equivalent couldn't work. A 2 degrees pendulum might work for vertical flight if it were damped properly. Without damping (which is the problem with mercury switches) you can get into a feedback loop and oscillate out of control as well as get false activiations.

How about....

curved tubes with a viscous and colored oil in them, and a bubble of air, like in a level. You could track the bubble in the tubes with LEDs and photodetectors, shining through the bubble or blocked by the oil.
There are a lot of very small gyros out there used in hobby R/C helicopters. Like this one:
https://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXVA43&P=ML
 

ResearchWorm

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You know, if you really want to get into building your own avionics suites, there are an awful lot of small component sized/low voltage (3v or less) parts that you can use in a high-g environment.

- Patch antennae GPS receivers
- Analog Devices has a whole series of MEMS gyroscope/accelleromters that are quite tiny.
- Small pressure sensors.

I've even seen IC's, essential over grown counter/timers that can directly control servos. Scary thing is that as sophisticated as that sounds, they're really only a couple of TTL/CMOS parts integrated into one package.

I would think that it should be possible to design a BASIC-52 or BasicSTAMP (TM) based microcontroller board to essentially function as an avionics controller for whatever peripherals you wanted. I'll have to look into it and see what I can find out.

Harm none,

ResearchWorm
 
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