FLYBOYJ
"THE GREAT GAZOO"
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The Reno Racing Engines
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jimh
Senior Airman
An airfoil is ALWAYS generating lift, even completely stalled it generates lift, just not enough to carry the load its attached to. It would be wise for you to pick up or download the FAA Pilot Handbooks and review what makes an airplane fly. A prop for a P-51 runs right around $100,000, the next time I go fly it I'll ask the owner if I should start looking into an 11ft ceiling fan...it will save him a TON of money! LOL the WHOLE point of a combustion chamber is to make pressure...either driving pistons, turbines or a rocket engine.
over and out
jim
over and out
jim
GregP
Major
Flyboyj, I don't think you can call it a true ducted fan; it was a shrouded propeller. But my point was that the design COULD use a ducted fan where the shrouded propeller was located ... IF the gearcase and fan would not mess up the CG. I think they WOULD mess up the CG and would also take the aircraft out of the Formula 1 category (probably on weight), but I already said that we'd have to have a ducted fan category as a separate racing class ... if anyone were interested in it.
I believe the JM-2 aircraft could have been made into winners if the desire was there, but Jim Miller didn't pursue the design farther than the JM-2.
All in all a neat-looking little plane that was somewhat dangerous to race. I understand two of them broke up in the air and contributed to the decision to retire Pusy Galore ... but that is simply what I heard at the time; it is not corroborated.
I believe the JM-2 aircraft could have been made into winners if the desire was there, but Jim Miller didn't pursue the design farther than the JM-2.
All in all a neat-looking little plane that was somewhat dangerous to race. I understand two of them broke up in the air and contributed to the decision to retire Pusy Galore ... but that is simply what I heard at the time; it is not corroborated.
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jimh
Senior Airman
Oh yea, I remember that airplane, but can you really call it a true ducted fan?
Yes, agreed, that is more like a 30's speed ring...but certainly a shroud that directs air.
jim
GregP
Major
If I'm not mistaken (could be), I believe the propeller shroud on the JM-2 was put there to have structural rigidity for the top of verticl fin and for the elevator, which hangs out behind the shroud and needed something for rigid support. I seem to reacall that from an interview with Jim Miller way back just after the earth cooled.
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Shortround6
Major General
There is this airplane but since nobody seems to have copied it in the last 40 years that may tell us something.
http://cdn-www.airliners.net/aviation-photos/middle/6/0/1/1793106.jpg
http://cdn-www.airliners.net/aviation-photos/middle/6/0/1/1793106.jpg
GregP
Major
I loved the Fantrainer, but it sort of disappeared. It had a LOT of great characteristics, but nobody bought it. Tough to figure.
To me, it looked like a shrouded prop, not a ducted fan ... but that might be wrong.
Interesting and innovative, but not a commercial success. And I thought it SHOULD have been.
To me, it looked like a shrouded prop, not a ducted fan ... but that might be wrong.
Interesting and innovative, but not a commercial success. And I thought it SHOULD have been.
- Thread starter
- #69
PWR4360-59B
Senior Airman
- 379
- May 27, 2008
Yeah but it works. I never said the venturi effect doesn't happen, radical up is to counter act the venturi effect and deflect the air down.
GregP
Major
Engguy,
From your posts, I can only ask if your real handle is Gaston. If so, hello again. If not, I apologize for asking.
From your posts, I can only ask if your real handle is Gaston. If so, hello again. If not, I apologize for asking.
- Thread starter
- #71
PWR4360-59B
Senior Airman
- 379
- May 27, 2008
Ah no not gaston, just another free thinker, when someone says it can't be done, I like to figure out how it can be. He must be a good guy, does he come here? If so where is he? I need his help. LOL
So what about the combustion pressure in a rocket engine? And an ION engine with none?
If you ever watch a bird, it picks its wings up and deflects air down to fly, in kind of a scooping motion. Notice how they go almost vertical and scoop the air especially on take off. Wow they are some darn good pilots. I just wish they could talk and tell us all about it.
So what about the combustion pressure in a rocket engine? And an ION engine with none?
If you ever watch a bird, it picks its wings up and deflects air down to fly, in kind of a scooping motion. Notice how they go almost vertical and scoop the air especially on take off. Wow they are some darn good pilots. I just wish they could talk and tell us all about it.
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GregP
Major
Glad you are a free thinker. That's how new inventions are thought up.
There is no engine anywhere that puts out a high-velocity stream of exhaust without a place for reaction. The only way to GET a high-velocity stream of exhaust is to enclose the front and the sides, leaving just one place for the exhaust to go ... out in the intended direction.
Pistons have the cylinder, and the combustion drives the pistons down. Jets have a combustion chamber and the opening is at the back, rockets are the same. Ion engines either use Coulomb force or Lorentz force to accelerate ions, and the stator is pushed in the direction opposite the direction the ions are accelerated. It functions like a combustion chamber in that the ion engine must be bolted to the engine mount, and the thrust from the stator is transmitted via the engine mount bolts, pretty much the same an any engine.
Not sure what you are trying to say by mentioning the ion engine in a way that seems to say it generates thurst from nowhere, but the stator absorbs the acceleration energy and has an impulse opposite to the ion exhaust. You can't send a stream of anything at high velocity unless it has something to push against ... unless the particles in the exhaust as massless. If they are, you don't have an engine.
There is no engine anywhere that puts out a high-velocity stream of exhaust without a place for reaction. The only way to GET a high-velocity stream of exhaust is to enclose the front and the sides, leaving just one place for the exhaust to go ... out in the intended direction.
Pistons have the cylinder, and the combustion drives the pistons down. Jets have a combustion chamber and the opening is at the back, rockets are the same. Ion engines either use Coulomb force or Lorentz force to accelerate ions, and the stator is pushed in the direction opposite the direction the ions are accelerated. It functions like a combustion chamber in that the ion engine must be bolted to the engine mount, and the thrust from the stator is transmitted via the engine mount bolts, pretty much the same an any engine.
Not sure what you are trying to say by mentioning the ion engine in a way that seems to say it generates thurst from nowhere, but the stator absorbs the acceleration energy and has an impulse opposite to the ion exhaust. You can't send a stream of anything at high velocity unless it has something to push against ... unless the particles in the exhaust as massless. If they are, you don't have an engine.
- Thread starter
- #73
PWR4360-59B
Senior Airman
- 379
- May 27, 2008
I miss understood you saying the combustion pressure pushing forward or did I? Anyway yes in agreement like the stator and rotor in a motor one is held and the other is free to react. In a rocket the whole of the engine and what its mounted to is the stator, and the velocity of the gases is the rotor. In space and a vaccum there is nothing to push on.
It is a reation of the velocity of the gases escaping that makes it move.
It is a reation of the velocity of the gases escaping that makes it move.
GregP
Major
Engguy,
In a rocket, there is a combustion chamber. The combustion chamber is the entire basis for the rocket, and you cannot HAVE a rocket without one. Basically a rocket is only a combustion chamber, fuel, an exhaust nozzle, and an igniter.
Assume a solid fuel rocket.
The fuel is in the combuastion chamber, usually with holes machined into it running along the long axis of the rocket. The solid fuel is ignited and produces a lot of gasseous discharge. The gasseous product of combustion fills the combustion chanber's free space and then the pressure starts rising very quickly. The exhaust opening is not large enough for the entire volume of gass to escape through, so the combusiton chamber pressurizes. The pressure pushes outward in all directions.
At all angles other than forward an backward, there is a comustion chamber wall in both diirections. and the outward pressure against an area produces force and it equalizes. In the fore and aft direction, the pressure forward creates a force forward that is much greater than the pressure backward creates a backward force because there is a rocket exhaust opening located at the back end, shaped to maximize the exhaust velocity. The difference in the forward force and the backward force at the exhaust nozzle is the thrust of the rocket.
Think of pressure in pounds per square foot. If you miltiply (pound / sq ft) by sq ft, you get pounds of force.
In the atmoshpere, the high-velocity exhaust slightly interacts with the atmosphere, but out in space, the only thrust is the forward force at the front of the combustion chamber that exceeds the backward force at the nozzle. If there is still fuel in the combustion chamber when you need to terminate thrust, you simply blow out the side of the combustion chamber with a length of det cord, and the fuel keeps burning until it is spent, but it produces no thrust because the combustion chamber is no longer closed off, and there can be no pressure built up inside it. That's how they do thrust termination in ICBM missiles and in any solid fuel booster to terminate thrust at a partcular point in time.
This is basic Physics. The reason rockets can work in a vacuum is they produce force internally and don't require atmosphere to operate. That is the basic difference between a rocket and a jet engine. The jet engine needs air to make the comustable air-fuel mixture and needs an air inlet. A rocket carries its own Qxidizer in the fuel, so it needs no air and, hence, no air inlet. It'll work underwater if you really want it to do so.
Since you want to invent things, you probably need to study physics and the engines you want to replace with your new invention types. It will be very tough to forge ahead if you don't understand how the engines you are trying to replace work in the first place. Engines don't run on intutive science, they run accrording to the laws of physics and thermodynamics in particular. To undestand Thermodynamics, you needs some engineering background and at least basic calculus.
If you succeed in inventing new engines without studying engineering, you will not exactly be alone since we DID have start SOMEHWERE, but you will be one of the very few who have managed to do so, and probably the only such person since slightly before WWI.
In a rocket, there is a combustion chamber. The combustion chamber is the entire basis for the rocket, and you cannot HAVE a rocket without one. Basically a rocket is only a combustion chamber, fuel, an exhaust nozzle, and an igniter.
Assume a solid fuel rocket.
The fuel is in the combuastion chamber, usually with holes machined into it running along the long axis of the rocket. The solid fuel is ignited and produces a lot of gasseous discharge. The gasseous product of combustion fills the combustion chanber's free space and then the pressure starts rising very quickly. The exhaust opening is not large enough for the entire volume of gass to escape through, so the combusiton chamber pressurizes. The pressure pushes outward in all directions.
At all angles other than forward an backward, there is a comustion chamber wall in both diirections. and the outward pressure against an area produces force and it equalizes. In the fore and aft direction, the pressure forward creates a force forward that is much greater than the pressure backward creates a backward force because there is a rocket exhaust opening located at the back end, shaped to maximize the exhaust velocity. The difference in the forward force and the backward force at the exhaust nozzle is the thrust of the rocket.
Think of pressure in pounds per square foot. If you miltiply (pound / sq ft) by sq ft, you get pounds of force.
In the atmoshpere, the high-velocity exhaust slightly interacts with the atmosphere, but out in space, the only thrust is the forward force at the front of the combustion chamber that exceeds the backward force at the nozzle. If there is still fuel in the combustion chamber when you need to terminate thrust, you simply blow out the side of the combustion chamber with a length of det cord, and the fuel keeps burning until it is spent, but it produces no thrust because the combustion chamber is no longer closed off, and there can be no pressure built up inside it. That's how they do thrust termination in ICBM missiles and in any solid fuel booster to terminate thrust at a partcular point in time.
This is basic Physics. The reason rockets can work in a vacuum is they produce force internally and don't require atmosphere to operate. That is the basic difference between a rocket and a jet engine. The jet engine needs air to make the comustable air-fuel mixture and needs an air inlet. A rocket carries its own Qxidizer in the fuel, so it needs no air and, hence, no air inlet. It'll work underwater if you really want it to do so.
Since you want to invent things, you probably need to study physics and the engines you want to replace with your new invention types. It will be very tough to forge ahead if you don't understand how the engines you are trying to replace work in the first place. Engines don't run on intutive science, they run accrording to the laws of physics and thermodynamics in particular. To undestand Thermodynamics, you needs some engineering background and at least basic calculus.
If you succeed in inventing new engines without studying engineering, you will not exactly be alone since we DID have start SOMEHWERE, but you will be one of the very few who have managed to do so, and probably the only such person since slightly before WWI.
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- Thread starter
- #75
PWR4360-59B
Senior Airman
- 379
- May 27, 2008
NASA - What Is a Rocket?
Its not me that needs the learnin here argue with Nasa instead of me. I have a good grounding in all the sciences. When someone is deficient they start attacking someone elses intellect, and or education, now you have me doing it. So I'll stop here. Lets not attack and just carry on a nice discussion.
Its not me that needs the learnin here argue with Nasa instead of me. I have a good grounding in all the sciences. When someone is deficient they start attacking someone elses intellect, and or education, now you have me doing it. So I'll stop here. Lets not attack and just carry on a nice discussion.
GregP
Major
Yeah, that's the plain text version of a basic science explanation, and it tells what happens, not why. Exhaust doesn't push on anything ... it is moving in the other direction. It's like I said,
F = ma ... Newton's Second Law. Go get an egnineering degree and then tell me how it works.
Meanwhile, no more lectures from me to you about how things work, invent them if you can. Let's just say I'll wait to hear about your new inventions with interest.
F = ma ... Newton's Second Law. Go get an egnineering degree and then tell me how it works.
Meanwhile, no more lectures from me to you about how things work, invent them if you can. Let's just say I'll wait to hear about your new inventions with interest.
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- Thread starter
- #77
PWR4360-59B
Senior Airman
- 379
- May 27, 2008
And you are inferring I didn't say that? My motor analogy didn't help did it?
GregP
Major
Yes, I am. Force doesn't come from nowhere, it comes from the pressure in the combustion chamber acting against the area of the front of the combustion chamber.
Look, you are arguing about things I taught, literally in school (Physics). And you are wrong.
In point of fact, really, I don't care to continue the discussion. You have engineers, aviation mechanics, and pilots telling you that you are wrong and you persist in arguing. As I said earlier, go get an engineering degree and then come back and argue the points. If you graduate, you won't be arguing anymore ...
Until then, I may disagree when you are wrong, but I won't tell you why by explanation since you obviously aren't interested. Be free and think, but back it up with experiments. If you don't do anyting else, at LEAST use the scientific method, going forward, instead of the one you've been using to date.
One last explanation.
The scientific method is to formulate a theory and then do your level best to prove it wrong, acting as your own worst critic, and assuming it IS wrong. If you can't, it might be true. Of course, that means other people can't prove it wrong either by experiments and actual results.
Good luck!
Look, you are arguing about things I taught, literally in school (Physics). And you are wrong.
In point of fact, really, I don't care to continue the discussion. You have engineers, aviation mechanics, and pilots telling you that you are wrong and you persist in arguing. As I said earlier, go get an engineering degree and then come back and argue the points. If you graduate, you won't be arguing anymore ...
Until then, I may disagree when you are wrong, but I won't tell you why by explanation since you obviously aren't interested. Be free and think, but back it up with experiments. If you don't do anyting else, at LEAST use the scientific method, going forward, instead of the one you've been using to date.
One last explanation.
The scientific method is to formulate a theory and then do your level best to prove it wrong, acting as your own worst critic, and assuming it IS wrong. If you can't, it might be true. Of course, that means other people can't prove it wrong either by experiments and actual results.
Good luck!
- Thread starter
- #79
PWR4360-59B
Senior Airman
- 379
- May 27, 2008
The force is the grounded to the rocket frame of the whole engine assembly. Its not from the combustion chamber in a rocket, especially if that rocket engine is an ion engine as it has zero combustion chamber. The push from the rocket engine is from the escaping gases at the nozzle. You originally said the combustion chamber force is pushing in the front direction of the rocket and that is what makes in go. And that is incorrect its the force developed at the rocket nozzle pushing rear ward that is doing the propelling forward since the nozzle accelerates the gases, the combustion chamber could be at the rear and all the pressure ducted through and elbow facing forward then looped around to the nozzle. Gosh whats the deal? I agree simple physics. I could have miss understood you, I used the balloon example, and I'm thinking you meant the expanding forward pressure in the chamber is what was pushing when it actually is the expanding rear ward pressure that is making it go forward. I guess pictures would really help what we both are trying to say.
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- Thread starter
- #80
PWR4360-59B
Senior Airman
- 379
- May 27, 2008
The statement is incorrect. The pressure would not be to the front if the combustion chamber was beside the nozzle in the rear and the tube or duct came out of the chamber at the front and curved 180 degrees into the nozzle. I can agree its is the pressure with in the chamber that causes the thrust. This has been the whole argument.
