The sickest video of returning from space ever

Quote from: markjo on July 28, 2016, 03:21:21 PM

Where exactly does SpaceX imply that the CoP and CoG are on the way up and on the way down?

Must have got called to duty a little early John. Cannot see the reality of my statement? CoP does not change and CoG has changed. Now the rockkitt ship is coming down, thrusters first...see below...a la broom...

Quote from: markjo on July 28, 2016, 02:43:43 PM

Incorrect.  CoP changes when the grid fins are deployed.

This changes CoG, not CoP...

Of course changing the aerodynamics changes the CoP.  What do you think grid fins do?

First, CoP cannot be in front of CoG...you admitted that...

When did I ever say that? 

Then, your lackeys come in and claim, WAIT!!! IT CAN TOO!!! Of course, this is bull, just like the fake CGI spayyzze sex puts out...as CoP is now in front of CoG as the booster comes down...Of course, this is demonstrable by sight as CoP does not change in a booster...it cannot.

So you're saying that you can determine CoP just by sight?

Quote from: totallackey on July 28, 2016, 05:00:05 PM

NASA states: "The conditions for a stable rocket are that the center of pressure must be located below the center of gravity." https://spaceflightsystems.grc.nasa.gov/education/rocket/rktstab.html

With this statement, all conditions of control (active or passive) serve to only help keep the rocket stable.

Proper interpretation of the text provided by totallackey.

Thank you.

Except you ignore the link provided is talking about model rockets with no active stability control.

That is why they put this note:

 "Modern full scale rockets do not usually rely on aerodynamics for stability. Full scale rockets pivot their exhaust nozzles to provide stability and control. That's why you don't see fins on a Delta, Titan, or Atlas booster."

They also mention more than once they are talking about model rockets or rockets with no active stability control.

Are you going to ignore that planes like the X-29 exist and fly?  Planes that are aerodynamically unstable and rely on active stability controlled by computers.  Why would you think they could do it with aircraft and not rockets?

And you ignore this:

"During flight both model rockets and full scale rockets must provide some system of stability and control. Stability indicates that if the flight path is slightly perturbed, the rocket will return to the previous path and not fly erratically. Control is the ability to maneuver the rocket during flight.Both models and full scale rockets are designed with passive stability within the atmosphere. The "passive" part means that the rocket will return to the flight path without moving any control surfaces. The conditions for stability are that the center of gravity must be located above the center of pressure. Model rockets have no provisions for control. After the rocket leaves the launch rail, it can go anywhere. You watch a model rocket fly; you can't control it. Model rockets often turn into the wind, in a maneuver called weather cocking, because of aerodynamic forces on the stability fins. Real rockets use very sophisticated instrumentation, computers, and high speed actuators for flight control. The early V2 had small vanes in the rocket nozzle which would deflect the thrust during flight. Most full scale rockets use a system called engine gimbals, in which the whole nozzle is rotated while the engine is firing."
https://spaceflightsystems.grc.nasa.gov/education/rocket/rktcompare.html

So, it puts to bed the the false notion CoP/CoG relationshiip is rendered null and void by the type of control system used. This talks about CoP and CoG relative to both model and large scale rockets. If CoP/CoG were a non-facotr in full scale rockets, it would clearly state this in the text...something like, "The CoP can be wherever in a large scale rocket. Consideration is not necessary." But it does not state this, does it sparky...No.

The reason? Because it is a RULE! That can never be ignored.

Put your airplane back in its box, because it is nowhere near the same animal.

Go have a drink with Geoff and John...Should be easy...You are all the same person...JREF refugee socks...

And you ignore this:

". . . . . . .
Both models and full scale rockets are designed with passive stability within the atmosphere. The "passive" part means that the rocket will return to the flight path without moving any control surfaces. The conditions for stability are that the center of gravity must be located above the center of pressure.
. . . . . . . . . "
https://spaceflightsystems.grc.nasa.gov/education/rocket/rktcompare.html

So, it puts to bed the the false notion CoP/CoG relationshiip is rendered null and void by the type of control system used.

This talks about CoP and CoG relative to both model and large scale rockets. If CoP/CoG were a non-facotr in full scale rockets, it would clearly state this in the text...something like, "The CoP can be wherever in a large scale rocket. Consideration is not necessary." But it does not state this, does it sparky...No.
The reason? Because it is a RULE! That can never be ignored.
Put your airplane back in its box, because it is nowhere near the same animal.

Well, actually Mr Lackey the stability control of a rocket and an aerodynamically unstable aircraft are not that different.

Go have a drink with Geoff and John...Should be easy...You are all the same person...JREF refugee socks...

I had wondered how you could be so insistent, yet still wrong. Now I understand, and it is not really your fault.

You claim "The reason? Because it is a RULE! That can never be ignored." No, there is no such RULE. There is a statement in an article aimed at model rocket builders.

You know something! I am going to shock you and turn down that drink offer and disagree with your reference.
And yes I know it is written by NASA, but this bit
"Both models and full scale rockets are designed with passive stability within the atmosphere. The 'passive' part means that the rocket will return to the flight path without moving any control surfaces. The conditions for stability are that the center of gravity must be located above the center of pressure"
is not strictly correct. Rockets with CoP ahead of CoG do not have "passive stability", but can be stabilised with dynamic control. Note that it goes on to say:
"Real rockets use very sophisticated instrumentation, computers, and high speed actuators for flight control. The early V2 had small vanes in the rocket nozzle which would deflect the thrust during flight. Most full scale rockets use a system called engine gimbals, in which the whole nozzle is rotated while the engine is firing."

The Saturn V simply did not have "passive stability" for most of its in-atmosphere flight. That is demonstrated in the graph and the accompanying statement I gave you in Re: The sickest video of returning from space ever « Reply #1149 on: July 26, 2016, 10:25:12 PM » . Yes, that reference is from a paper by NASA about the stability of the Saturn V + Apollo.

Now if you really knew your stuff, you could claim that "dynamic stability control via gimbaled engines" does in effect move the Centre of Pressure "dynamically". Though the "model rocket" reference says quite specifically that
"Both models and full scale rockets are designed with passive stability within the atmosphere." 
But many large rockets simply do not have passive stability, that is a fact.

I can't explain why that reference you gave has that statement because it is not strictly correct. All I can guess is that it is aimed at model rocket builders, and the writer made a bit of a slip. Certainly all rockets need to be stable and usually model rockets have to rely only on "passive stability". Dynamic control is certainly easier if a rocket has "passive stability", but that is not always possible, as in the Saturn V.

There are a couple of other parts on the same site that do not include the "large" rocket statement,  Rocket Stability Condition and Rocket Stability. 
These both have the rider at the end
"NOTE: Modern full scale rockets do not usually rely on aerodynamics for stability. Full scale rockets pivot their exhaust nozzles to provide stability and control. That's why you don't see fins on a Delta, Titan, or Atlas booster."

Look, I don't blame you for this confusion, unless you had a background involving control systems and the like, you could hardly be expected to pick it up.

Quote from: Woody on July 28, 2016, 06:28:24 PM

Quote from: totallackey on July 28, 2016, 05:00:05 PM

NASA states: "The conditions for a stable rocket are that the center of pressure must be located below the center of gravity." https://spaceflightsystems.grc.nasa.gov/education/rocket/rktstab.html

With this statement, all conditions of control (active or passive) serve to only help keep the rocket stable.

Proper interpretation of the text provided by totallackey.

Thank you.

Except you ignore the link provided is talking about model rockets with no active stability control.

That is why they put this note:

 "Modern full scale rockets do not usually rely on aerodynamics for stability. Full scale rockets pivot their exhaust nozzles to provide stability and control. That's why you don't see fins on a Delta, Titan, or Atlas booster."

They also mention more than once they are talking about model rockets or rockets with no active stability control.

Are you going to ignore that planes like the X-29 exist and fly?  Planes that are aerodynamically unstable and rely on active stability controlled by computers.  Why would you think they could do it with aircraft and not rockets?

And you ignore this:

"During flight both model rockets and full scale rockets must provide some system of stability and control. Stability indicates that if the flight path is slightly perturbed, the rocket will return to the previous path and not fly erratically. Control is the ability to maneuver the rocket during flight.Both models and full scale rockets are designed with passive stability within the atmosphere. The "passive" part means that the rocket will return to the flight path without moving any control surfaces. The conditions for stability are that the center of gravity must be located above the center of pressure. Model rockets have no provisions for control. After the rocket leaves the launch rail, it can go anywhere. You watch a model rocket fly; you can't control it. Model rockets often turn into the wind, in a maneuver called weather cocking, because of aerodynamic forces on the stability fins. Real rockets use very sophisticated instrumentation, computers, and high speed actuators for flight control. The early V2 had small vanes in the rocket nozzle which would deflect the thrust during flight. Most full scale rockets use a system called engine gimbals, in which the whole nozzle is rotated while the engine is firing."
https://spaceflightsystems.grc.nasa.gov/education/rocket/rktcompare.html

So, it puts to bed the the false notion CoP/CoG relationshiip is rendered null and void by the type of control system used. This talks about CoP and CoG relative to both model and large scale rockets. If CoP/CoG were a non-facotr in full scale rockets, it would clearly state this in the text...something like, "The CoP can be wherever in a large scale rocket. Consideration is not necessary." But it does not state this, does it sparky...No.

The reason? Because it is a RULE! That can never be ignored.

Put your airplane back in its box, because it is nowhere near the same animal.

Go have a drink with Geoff and John...Should be easy...You are all the same person...JREF refugee socks...

*sigh*

And the baby is back with the same lack of education.

CoM & CoG are near enough interchangeable in Terrestrial conditions...

So thanks Geoff for definitively proving the Saturn V was fake.

Here are the lies you refuse to adress yet again:

Quote from: totallackey on July 19, 2016, 04:32:26 AM

Depends on how much you think your pretty plane relates to rocketry and the topic at hand...

I got a clue for you: IT DOESN'T HAVE A FUCKING THING TO DO WITH ANYTHING WE ARE DISCUSSING.

Jesus, you are fucking dense or something.

Do you believe that the centre-of-pressure and centre-of-gravity don't have to be accounted for with regards to airplanes and jets?

The centre of lift of an airplane wing & the centre of pressure of a rocket are two completely different things.

Only a retarded sock-puppet shill would try to confuse them.

This is the THIRD time I've had to tell you on this fucking thread alone btw...

Which'd get you banned off any normal forum.

But as you shills run this one I guess you'll just wait a few pages & try again...

Because shills.

Plus this:

Quote from: Papa Legba on July 16, 2016, 10:20:18 AM

Quote from: Rayzor on July 16, 2016, 07:38:53 AM

how do they drive the turbines?

You tell me; you're the fake 'expert'.

Anyhoo; you are avoiding the point.

Again:

How do you 're-ignite' a gas that's already been ignited?

How did it get 'de-ignited' in the first place?

The gas generators run on a very rich fuel mix so not all of the fuel gets burned.  The fuel rich exhaust is fed into the engine nozzle extension (well past the combustion chamber and throat) where it may or may not burn on its own.

Did you ever notice the dark gasses coming out of the F-1 engine when the Saturn V takes off?  That's the fuel rich exhaust from the gas generator just before it re-ignites.

Sadly for you, here is a a video of teh NASA rokkit enjynerrz stating at 3:50 that yes, teh sparklers ARE to ignite excess hydrogen from teh rokkit enjynnz:



Here is a hydrogen safety sheet stating that hydrogen dissipates harmlessly in open air:

http://arhab.org/pdfs/h2_safety_fsheet.pdf

So yeah; setting fire to it would seem to be the least safe thing to do, especially as it would potentially cause premature ignition; you know, before the correct rate of flow was established in teh combuschun chaymbah?

Which could make the whole thing blow to bits?

Which happened all the time in early rocket tests?

Which is why they never, ever, had sparks shooting everywhere beneath their rockets during ignition?

LOL!!!

You are all busted, a-fucking-gain!

The sparklers are there to ignite the silly fake model engines...

Because they do not have 'combustion chambers' & are not part of a 'shpayze-rokkit'...

They are shitty stage-props; big bunsen burners, at best.

Toodle-pip, Losers!

I swear, every time he curses somebody out, it is him just screaming for love. We must band together and give Papa Legba the love he deserves. Everybody together for one purpose. We can make a difference.

CoM & CoG are near enough interchangeable in Terrestrial conditions...

So thanks Geoff for definitively proving the Saturn V was fake.

Here are the lies you refuse to adress yet again:

Quote from: totallackey on July 19, 2016, 04:32:26 AM

Depends on how much you think your pretty plane relates to rocketry and the topic at hand...

I got a clue for you: IT DOESN'T HAVE A FUCKING THING TO DO WITH ANYTHING WE ARE DISCUSSING.

Jesus, you are fucking dense or something.

Do you believe that the centre-of-pressure and centre-of-gravity don't have to be accounted for with regards to airplanes and jets?

The centre of lift of an airplane wing & the centre of pressure of a rocket are two completely different things.

Only a retarded sock-puppet shill would try to confuse them.

This is the THIRD time I've had to tell you on this fucking thread alone btw...

Which'd get you banned off any normal forum.

But as you shills run this one I guess you'll just wait a few pages & try again...

Because shills.

Plus this:

Quote from: Papa Legba on July 16, 2016, 10:20:18 AM

Quote from: Rayzor on July 16, 2016, 07:38:53 AM

how do they drive the turbines?

You tell me; you're the fake 'expert'.

Anyhoo; you are avoiding the point.

Again:

How do you 're-ignite' a gas that's already been ignited?

How did it get 'de-ignited' in the first place?

The gas generators run on a very rich fuel mix so not all of the fuel gets burned.  The fuel rich exhaust is fed into the engine nozzle extension (well past the combustion chamber and throat) where it may or may not burn on its own.

Did you ever notice the dark gasses coming out of the F-1 engine when the Saturn V takes off?  That's the fuel rich exhaust from the gas generator just before it re-ignites.

Sadly for you, here is a a video of teh NASA rokkit enjynerrz stating at 3:50 that yes, teh sparklers ARE to ignite excess hydrogen from teh rokkit enjynnz:



Here is a hydrogen safety sheet stating that hydrogen dissipates harmlessly in open air:

http://arhab.org/pdfs/h2_safety_fsheet.pdf

So yeah; setting fire to it would seem to be the least safe thing to do, especially as it would potentially cause premature ignition; you know, before the correct rate of flow was established in teh combuschun chaymbah?

Which could make the whole thing blow to bits?

Which happened all the time in early rocket tests?

Which is why they never, ever, had sparks shooting everywhere beneath their rockets during ignition?

LOL!!!

You are all busted, a-fucking-gain!

The sparklers are there to ignite the silly fake model engines...

Because they do not have 'combustion chambers' & are not part of a 'shpayze-rokkit'...

They are shitty stage-props; big bunsen burners, at best.

Toodle-pip, Losers!

Only a retarded sock-puppet shill would try to confuse them.

This is the THIRD time I've had to tell you on this fucking thread alone btw...

Which'd get you banned off any normal forum.

Gratuitous profanity and verbal abuse would likely get you banned off any normal forum too.

This is the THIRD time I've had to tell you on this fucking thread alone btw...

Which'd get you banned off any normal forum.

Actually, it's the 16th time you've copy-pasted that. You better work on your cop-paste skills.

Is there anything you don't fail at?

Hey look! I can copy posts, too! 

You know what else gets you banned on any forum? Multiple infractions of low content, inflammatory remarks, and personal attacks after myriads of warnings!  Enjoy your vacation.  Take a walk around the block. Breathe the fresh air deeply. The sky is manna for the eyes, as the Hazal say.

Repent, ye sinners!

Aw. This thread is going to get really boring without him around...

until totallackey miraculously shows up again 

Quote from: Woody on July 28, 2016, 06:28:24 PM

Quote from: totallackey on July 28, 2016, 05:00:05 PM

NASA states: "The conditions for a stable rocket are that the center of pressure must be located below the center of gravity." https://spaceflightsystems.grc.nasa.gov/education/rocket/rktstab.html

With this statement, all conditions of control (active or passive) serve to only help keep the rocket stable.

Proper interpretation of the text provided by totallackey.

Thank you.

Except you ignore the link provided is talking about model rockets with no active stability control.

That is why they put this note:

 "Modern full scale rockets do not usually rely on aerodynamics for stability. Full scale rockets pivot their exhaust nozzles to provide stability and control. That's why you don't see fins on a Delta, Titan, or Atlas booster."

They also mention more than once they are talking about model rockets or rockets with no active stability control.

Are you going to ignore that planes like the X-29 exist and fly?  Planes that are aerodynamically unstable and rely on active stability controlled by computers.  Why would you think they could do it with aircraft and not rockets?

And you ignore this:

"During flight both model rockets and full scale rockets must provide some system of stability and control. Stability indicates that if the flight path is slightly perturbed, the rocket will return to the previous path and not fly erratically. Control is the ability to maneuver the rocket during flight.Both models and full scale rockets are designed with passive stability within the atmosphere. The "passive" part means that the rocket will return to the flight path without moving any control surfaces. The conditions for stability are that the center of gravity must be located above the center of pressure. Model rockets have no provisions for control. After the rocket leaves the launch rail, it can go anywhere. You watch a model rocket fly; you can't control it. Model rockets often turn into the wind, in a maneuver called weather cocking, because of aerodynamic forces on the stability fins. Real rockets use very sophisticated instrumentation, computers, and high speed actuators for flight control. The early V2 had small vanes in the rocket nozzle which would deflect the thrust during flight. Most full scale rockets use a system called engine gimbals, in which the whole nozzle is rotated while the engine is firing."
https://spaceflightsystems.grc.nasa.gov/education/rocket/rktcompare.html

So, it puts to bed the the false notion CoP/CoG relationshiip is rendered null and void by the type of control system used. This talks about CoP and CoG relative to both model and large scale rockets. If CoP/CoG were a non-facotr in full scale rockets, it would clearly state this in the text...something like, "The CoP can be wherever in a large scale rocket. Consideration is not necessary." But it does not state this, does it sparky...No.

The reason? Because it is a RULE! That can never be ignored.

Put your airplane back in its box, because it is nowhere near the same animal.

Go have a drink with Geoff and John...Should be easy...You are all the same person...JREF refugee socks...

NASA publishes plenty of stuff that says otherwise.  Yes when possible it is better to keep the COP behind the COG the entire time the rocket is in the atmosphere or at least the lower part.

Did you not notice the Saturn V for the Apollo 11 mission graphic?  Why would NASA deny that the COP can be ahead of the COG and at the same time publicly provide information saying the opposite?

What you are referencing is something targeted towards model rocket enthusiast.  Explaining how to make a stable rocket that does not have any active controls.  It is why they add the note you seem not want to accept.

 "Modern full scale rockets do not usually rely on aerodynamics for stability. Full scale rockets pivot their exhaust nozzles to provide stability and control. That's why you don't see fins on a Delta, Titan, or Atlas booster."
 
What does aerodynamic stability mean to you in this context? To me it means what it means every where else I have read it. If I was asked or if I ask anyone to design a aerodynamically stable rocket I would expect it would have the COP behind the COG.  If I asked someone to design a stable rocket I would not 100% expect the COP to remain behind the COG during the entire flight.  Since there are methods that are available to maintain stability.

Aircraft and rockets are similar enough.  They both need to fly through the atmosphere and need to maintain stability.  Are you saying the COP and COG do not effect aircraft stability? 

CoM & CoG are near enough interchangeable in Terrestrial conditions...

So thanks Geoff for definitively proving the Saturn V was fake.

Here are the lies you refuse to adress yet again:

1) Geoff has not been around for a long, long time, that post was from nexus. I guess you're still smarting for the  thrashings he gave you.  . Poor Papa!
2) Thanks for "CoM & CoG are near enough interchangeable"! I have been trying to hammer that into your Lackey for ages!
3) I do believe we have convincingly proved that almost all modern rockets have to rely on "dynamic" stability.

It is completely obvious to anyone a rocket with no forward velocity can have no aerodynamic stability - no movement no "aerodynamics ".

Hence all large rockets that accelerate slowly at first must be stabilised using some form of thrust vectoring, using vanes in the exhaust, differential thrust from multiple engines or (now more commonly) gimballed engines.

The stability control of a rocket under these conditions is very like the "balancing broomstick" problem, and none of your blustering and  Copy Pasta will change that.

So, no neither you nor we have proved "the Saturn V was fake", just that you haven't learnt a thing yet.

Quote from: totallackey on July 29, 2016, 03:25:09 AM

And you ignore this:

". . . . . . .
Both models and full scale rockets are designed with passive stability within the atmosphere. The "passive" part means that the rocket will return to the flight path without moving any control surfaces. The conditions for stability are that the center of gravity must be located above the center of pressure.
. . . . . . . . . "
https://spaceflightsystems.grc.nasa.gov/education/rocket/rktcompare.html

So, it puts to bed the the false notion CoP/CoG relationshiip is rendered null and void by the type of control system used.

This talks about CoP and CoG relative to both model and large scale rockets. If CoP/CoG were a non-facotr in full scale rockets, it would clearly state this in the text...something like, "The CoP can be wherever in a large scale rocket. Consideration is not necessary." But it does not state this, does it sparky...No.
The reason? Because it is a RULE! That can never be ignored.
Put your airplane back in its box, because it is nowhere near the same animal.

Well, actually Mr Lackey the stability control of a rocket and an aerodynamically unstable aircraft are not that different.

Quote from: totallackey

Go have a drink with Geoff and John...Should be easy...You are all the same person...JREF refugee socks...

I had wondered how you could be so insistent, yet still wrong. Now I understand, and it is not really your fault.

You claim "The reason? Because it is a RULE! That can never be ignored." No, there is no such RULE. There is a statement in an article aimed at model rocket builders.

You know something! I am going to shock you and turn down that drink offer and disagree with your reference.
And yes I know it is written by NASA, but this bit
"Both models and full scale rockets are designed with passive stability within the atmosphere. The 'passive' part means that the rocket will return to the flight path without moving any control surfaces. The conditions for stability are that the center of gravity must be located above the center of pressure"
is not strictly correct. Rockets with CoP ahead of CoG do not have "passive stability", but can be stabilised with dynamic control. Note that it goes on to say:
"Real rockets use very sophisticated instrumentation, computers, and high speed actuators for flight control. The early V2 had small vanes in the rocket nozzle which would deflect the thrust during flight. Most full scale rockets use a system called engine gimbals, in which the whole nozzle is rotated while the engine is firing."

The Saturn V simply did not have "passive stability" for most of its in-atmosphere flight. That is demonstrated in the graph and the accompanying statement I gave you in Re: The sickest video of returning from space ever « Reply #1149 on: July 26, 2016, 10:25:12 PM » . Yes, that reference is from a paper by NASA about the stability of the Saturn V + Apollo.

Now if you really knew your stuff, you could claim that "dynamic stability control via gimbaled engines" does in effect move the Centre of Pressure "dynamically". Though the "model rocket" reference says quite specifically that
"Both models and full scale rockets are designed with passive stability within the atmosphere." 
But many large rockets simply do not have passive stability, that is a fact.

I can't explain why that reference you gave has that statement because it is not strictly correct. All I can guess is that it is aimed at model rocket builders, and the writer made a bit of a slip. Certainly all rockets need to be stable and usually model rockets have to rely only on "passive stability". Dynamic control is certainly easier if a rocket has "passive stability", but that is not always possible, as in the Saturn V.

There are a couple of other parts on the same site that do not include the "large" rocket statement,  Rocket Stability Condition and Rocket Stability. 
These both have the rider at the end
"NOTE: Modern full scale rockets do not usually rely on aerodynamics for stability. Full scale rockets pivot their exhaust nozzles to provide stability and control. That's why you don't see fins on a Delta, Titan, or Atlas booster."

Look, I don't blame you for this confusion, unless you had a background involving control systems and the like, you could hardly be expected to pick it up.

Here we have a drunk disagreeing with NASA...funny...

The only reason for the disagreement is the material from NASA clearly provces him wrong.

I have posted my references. What have the socks posted? Their        up opinion...

There is no ambiguity in the writings from NASA.

If the writing from NASA does match their opinion, it is OK.

If it does not, then      it they say...listen to us anyway.

You three multiple purpose socks can GFY collective selves. Have fun with the sticky gauges.

Just out of curiosity, where does NASA say that unstable aircraft/spacecraft can't fly?

Quote from: totallackey on July 29, 2016, 03:25:09 AM

Quote from: Woody on July 28, 2016, 06:28:24 PM

Quote from: totallackey on July 28, 2016, 05:00:05 PM

NASA states: "The conditions for a stable rocket are that the center of pressure must be located below the center of gravity." https://spaceflightsystems.grc.nasa.gov/education/rocket/rktstab.html

With this statement, all conditions of control (active or passive) serve to only help keep the rocket stable.

Proper interpretation of the text provided by totallackey.

Thank you.

Except you ignore the link provided is talking about model rockets with no active stability control.

That is why they put this note:

 "Modern full scale rockets do not usually rely on aerodynamics for stability. Full scale rockets pivot their exhaust nozzles to provide stability and control. That's why you don't see fins on a Delta, Titan, or Atlas booster."

They also mention more than once they are talking about model rockets or rockets with no active stability control.

Are you going to ignore that planes like the X-29 exist and fly?  Planes that are aerodynamically unstable and rely on active stability controlled by computers.  Why would you think they could do it with aircraft and not rockets?

And you ignore this:

"During flight both model rockets and full scale rockets must provide some system of stability and control. Stability indicates that if the flight path is slightly perturbed, the rocket will return to the previous path and not fly erratically. Control is the ability to maneuver the rocket during flight.Both models and full scale rockets are designed with passive stability within the atmosphere. The "passive" part means that the rocket will return to the flight path without moving any control surfaces. The conditions for stability are that the center of gravity must be located above the center of pressure. Model rockets have no provisions for control. After the rocket leaves the launch rail, it can go anywhere. You watch a model rocket fly; you can't control it. Model rockets often turn into the wind, in a maneuver called weather cocking, because of aerodynamic forces on the stability fins. Real rockets use very sophisticated instrumentation, computers, and high speed actuators for flight control. The early V2 had small vanes in the rocket nozzle which would deflect the thrust during flight. Most full scale rockets use a system called engine gimbals, in which the whole nozzle is rotated while the engine is firing."
https://spaceflightsystems.grc.nasa.gov/education/rocket/rktcompare.html

So, it puts to bed the the false notion CoP/CoG relationshiip is rendered null and void by the type of control system used. This talks about CoP and CoG relative to both model and large scale rockets. If CoP/CoG were a non-facotr in full scale rockets, it would clearly state this in the text...something like, "The CoP can be wherever in a large scale rocket. Consideration is not necessary." But it does not state this, does it sparky...No.

The reason? Because it is a RULE! That can never be ignored.

Put your airplane back in its box, because it is nowhere near the same animal.

Go have a drink with Geoff and John...Should be easy...You are all the same person...JREF refugee socks...

NASA publishes plenty of stuff that says otherwise.  Yes when possible it is better to keep the COP behind the COG the entire time the rocket is in the atmosphere or at least the lower part.

Did you not notice the Saturn V for the Apollo 11 mission graphic?  Why would NASA deny that the COP can be ahead of the COG and at the same time publicly provide information saying the opposite?

What you are referencing is something targeted towards model rocket enthusiast.  Explaining how to make a stable rocket that does not have any active controls.  It is why they add the note you seem not want to accept.

 "Modern full scale rockets do not usually rely on aerodynamics for stability. Full scale rockets pivot their exhaust nozzles to provide stability and control. That's why you don't see fins on a Delta, Titan, or Atlas booster."
 
What does aerodynamic stability mean to you in this context? To me it means what it means every where else I have read it. If I was asked or if I ask anyone to design a aerodynamically stable rocket I would expect it would have the COP behind the COG.  If I asked someone to design a stable rocket I would not 100% expect the COP to remain behind the COG during the entire flight.  Since there are methods that are available to maintain stability.

Aircraft and rockets are similar enough.  They both need to fly through the atmosphere and need to maintain stability.  Are you saying the COP and COG do not effect aircraft stability?

Once again, I perfectly and properly understand the inclusion of the note. The note does not alleviate nor mitigate nor disqualify the fact (RULE) that CoP must be behind CoG. If it did, the writing would clearly state that fact. It does not nor can it.

You are the one interpreting the writing in an erroneous manner.

Simple resolution: Go ahead and get a NASA scientist to write that my interpretation of the passage is incorrect. You can't and you know it.

Aircraft and rockets are not similar enough to apply in this situation.

Just out of curiosity, where does NASA say that unstable aircraft/spacecraft can't fly?

You okay John? The question seems delusional...

Quote from: markjo on August 01, 2016, 06:56:36 AM

Just out of curiosity, where does NASA say that unstable aircraft/spacecraft can't fly?

You okay John? The question seems delusional...

I'm fine, but I'm still not John.

You do realize that many modern jet fighters are designed to be inherently unstable in flight, don't you?  What keeps them from crashing all the time?

In fact, DARPA said that the X-29 was the most aerodynamically unstable aircraft ever built, but it flew just fine.
http://www.darpa.mil/about-us/timeline/x29

Quote from: totallackey on August 01, 2016, 11:23:38 AM

Quote from: markjo on August 01, 2016, 06:56:36 AM

Just out of curiosity, where does NASA say that unstable aircraft/spacecraft can't fly?

You okay John? The question seems delusional...

I'm fine, but I'm still not John.

You do realize that many modern jet fighters are designed to be inherently unstable in flight, don't you?  What keeps them from crashing all the time?

In fact, DARPA said that the X-29 was the most aerodynamically unstable aircraft ever built, but it flew just fine.
http://www.darpa.mil/about-us/timeline/x29

What does an X29 have to do with a rokkitt...

Answer > NOTHING.

Thanks for attempting to derail the thread, once again, John.

Once again, NASA has already published the fact CoP must be behind CoG in order for any rokkitt to remain stable in flight. If there were conditions allowing otherwise, any addendum would be clearly marked; in other words, the writing would state: "With the exception of certain active control systems, such as engine gimbaling."

The writing does not state this, nor can it.

It is really funny how you keep repeating exactly what Papa Legba failed to understand. It's almost like you're his alt or something.

Quote from: markjo on August 01, 2016, 12:26:04 PM

Quote from: totallackey on August 01, 2016, 11:23:38 AM

Quote from: markjo on August 01, 2016, 06:56:36 AM

Just out of curiosity, where does NASA say that unstable aircraft/spacecraft can't fly?

You okay John? The question seems delusional...

I'm fine, but I'm still not John.

You do realize that many modern jet fighters are designed to be inherently unstable in flight, don't you?  What keeps them from crashing all the time?

In fact, DARPA said that the X-29 was the most aerodynamically unstable aircraft ever built, but it flew just fine.
http://www.darpa.mil/about-us/timeline/x29

What does an X29 have to do with a rokkitt...

It has lots to do with your claim that unstable things can't fly.

Once again, NASA has already published the fact CoP must be behind CoG in order for any rokkitt to remain stable in flight.

You do understand that the page that you're referring to is talking about model rockets, don't you?

If there were conditions allowing otherwise, any addendum would be clearly marked; in other words, the writing would state: "With the exception of certain active control systems, such as engine gimbaling."

The writing does not state this, nor can it.

Actually, it does state that, you just keep ignoring it.

NOTE: Modern full scale rockets do not usually rely on aerodynamics for stability. Full scale rockets pivot their exhaust nozzles to provide stability and control. That's why you don't see fins on a Delta, Titan, or Atlas booster.

Quote from: totallackey on August 02, 2016, 09:13:43 AM

Quote from: markjo on August 01, 2016, 12:26:04 PM

Quote from: totallackey on August 01, 2016, 11:23:38 AM

Quote from: markjo on August 01, 2016, 06:56:36 AM

Just out of curiosity, where does NASA say that unstable aircraft/spacecraft can't fly?

You okay John? The question seems delusional...

I'm fine, but I'm still not John.

You do realize that many modern jet fighters are designed to be inherently unstable in flight, don't you?  What keeps them from crashing all the time?

In fact, DARPA said that the X-29 was the most aerodynamically unstable aircraft ever built, but it flew just fine.
http://www.darpa.mil/about-us/timeline/x29

What does an X29 have to do with a rokkitt...

It has lots to do with your claim that unstable things can't fly.

Quote from: totallackey on August 02, 2016, 09:13:43 AM

Once again, NASA has already published the fact CoP must be behind CoG in order for any rokkitt to remain stable in flight.

You do understand that the page that you're referring to is talking about model rockets, don't you?

Quote from: totallackey on August 02, 2016, 09:13:43 AM

If there were conditions allowing otherwise, any addendum would be clearly marked; in other words, the writing would state: "With the exception of certain active control systems, such as engine gimbaling."

The writing does not state this, nor can it.

Actually, it does state that, you just keep ignoring it.

Quote from: https://spaceflightsystems.grc.nasa.gov/education/rocket/rktstab.html

NOTE: Modern full scale rockets do not usually rely on aerodynamics for stability. Full scale rockets pivot their exhaust nozzles to provide stability and control. That's why you don't see fins on a Delta, Titan, or Atlas booster.

The text is referring to all rokkitts and you know it, John.

I have already explained the note at the bottom in its proper context. You keep ignoring it, cause it busts you in the chops.

Unstable things flying have nothing to do with the current subject matter of a rokkitt booster supposedly flying with CoP no longer behind CoG...

Quote from: markjo on August 02, 2016, 11:10:08 AM

Quote from: totallackey on August 02, 2016, 09:13:43 AM

Quote from: markjo on August 01, 2016, 12:26:04 PM

Quote from: totallackey on August 01, 2016, 11:23:38 AM

Quote from: markjo on August 01, 2016, 06:56:36 AM

Just out of curiosity, where does NASA say that unstable aircraft/spacecraft can't fly?

You okay John? The question seems delusional...

I'm fine, but I'm still not John.

You do realize that many modern jet fighters are designed to be inherently unstable in flight, don't you?  What keeps them from crashing all the time?

In fact, DARPA said that the X-29 was the most aerodynamically unstable aircraft ever built, but it flew just fine.
http://www.darpa.mil/about-us/timeline/x29

What does an X29 have to do with a rokkitt...

It has lots to do with your claim that unstable things can't fly.

Quote from: totallackey on August 02, 2016, 09:13:43 AM

Once again, NASA has already published the fact CoP must be behind CoG in order for any rokkitt to remain stable in flight.

You do understand that the page that you're referring to is talking about model rockets, don't you?

Quote from: totallackey on August 02, 2016, 09:13:43 AM

If there were conditions allowing otherwise, any addendum would be clearly marked; in other words, the writing would state: "With the exception of certain active control systems, such as engine gimbaling."

The writing does not state this, nor can it.

Actually, it does state that, you just keep ignoring it.

Quote from: https://spaceflightsystems.grc.nasa.gov/education/rocket/rktstab.html

NOTE: Modern full scale rockets do not usually rely on aerodynamics for stability. Full scale rockets pivot their exhaust nozzles to provide stability and control. That's why you don't see fins on a Delta, Titan, or Atlas booster.

The text is referring to all rokkitts and you know it, John.

Then why does it say "full scale rockets"?  Twice.

I have already explained the note at the bottom in its proper context. You keep ignoring it, cause it busts you in the chops.

No, I keep ignoring it because it's wrong.

Unstable things flying have nothing to do with the current subject matter of a rokkitt booster supposedly flying with CoP no longer behind CoG...

So what exactly do you suppose happens when the CoP is in front of the CoG?  Does the rocket become unstable?  Does it become uncontrollable?  Does it just stop in mid-air because it can no longer fly?

Unstable things flying have nothing to do with the current subject matter of a rokkitt booster supposedly flying with CoP no longer behind CoG...

Just for your information:

Maybe you had better explain just what YOU think is the difference between CoG and CoM. Yes, I'm well aware of the "physics" definition, but as you well know there is no difference when in a uniform gravitational field. So please carefully explain why you think the "technical difference" matters. Then explain just how a rocket does fly with the CoP is forward the CoM. This applies to most large rockets in use today. So, if CoG is the important parameter, please explain why it is CoM plotted in this graph? Do you know something that those plotting the graph didn't. How do YOU interpret the following words: Quote Another problem is that the vehicles are aerodynamically unstable during most of the propelled flight in the atmosphere. As an example, Figure 6 is a plot of the center of pressure and the center of mass for the first phase of the Saturn V and shows that the vehicle is unstable except for a short period of time around the 60th flight second. from page 9 of the above document! and here is the figure on the right: Surely, even you are smart enough to interpret this "plot of the center of pressure (CoP) and the center of Mass (CoM)". In that figure you can see clearly see that the Centre of Pressure (CoP) is forward of the Centre of Mass (CoM) for almost all the flight. In other words the Saturn V is purely reliant on the vectored thrust from the gimballed engines for stability - ie dynamic stability!

What matters is what NASA wrote: CoP must be behind CoG. Therefore, spayzze sexx is a hoax.

You can make a claim the little note at the end renders the prior writing null and void, but this claim merely cements the ignorance of the subject material on the part of the reader.

Once again, this is quite curable. Either get an official explanation from NASA that clearly states CoP/CoG is immaterial in the matter of large scale rockets (which you won't, because you can't) or go back to         school and learn how to         read. Word of advice: Remove the gauges from your arse prior to entering the school. Schools now have metal detectors

And stop bringing non-existent crapola into the discussion...

Or... You could test it yourself!

What matters is what NASA wrote: CoP must be behind CoG.

Again, what exactly do you think happens if the CoP is in front of CoG?

Either get an official explanation from NASA that clearly states CoP/CoG is immaterial in the matter of large scale rockets (which you won't, because you can't) or go back to         school and learn how to         read.

I never said that CoP/CoG is immaterial.  I'm just saying that a certain amount of instability caused by CoP being in front of CoG can be overcome by using various active control methods, such as engine gimbaling and grid fins.

What matters is what NASA wrote: CoP must be behind CoG. Therefore, spayzze sexx is a hoax.

You can make a claim the little note at the end renders the prior writing null and void, but this claim merely cements the ignorance of the subject material on the part of the reader.

Once again, this is quite curable. Either get an official explanation from NASA that clearly states CoP/CoG is immaterial in the matter of large scale rockets (which you won't, because you can't) or go back to         school and learn how to         read. Word of advice: Remove the gauges from your arse prior to entering the school. Schools now have metal detectors

And stop bringing non-existent crapola into the discussion...

You're starting to sound more and more like papa.