# Questions tagged [rocket]

For questions about rockets as they pertain to aviation. Questions about rockets in the context of space are off topic here.

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### Estimate the drag caused by wind on a free falling body

I'm trying to solve the following problem for my masters thesis: Estimate the drag caused by wind on a free falling body from H altitude. H is in range of 300-1000 meters. What would be the best way ...
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2k views

### What is the difference between a guided rocket and a guided missile?

Pakistan’s ‘Flat Trajectory’ Fatah-II Missile A Formidable Threat To India’s S-400 Missile System- Experts According to this news article, Pakistan's Fatah-II is a guided rocket artillery. What is ...
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### How to build a rocket? [closed]

I am trying to build a rocket (a small one for scientific purposes) for the very first time, I've never tried to do that before, and I can say I have almost little to no knowledge about this, so I am ...
57 views

### What's the most cost-effective way to get a group to get their Junior HPR Level 1 certification?

I'm apart of Civil Air Patrol and trying to get other cadets to get their Advanced Rocketry certificates, but the Challenger (Stage V) phase requires a completion of a NAR Junior HPR L1 certification. ...
631 views

### Could entrained air be used to increase rocket efficiency, like a bypass fan?

Could entrained air flow could be used to increase thrust in the similar way to how a bypass fan works? - The total thrust is √(2𝜈𝑃) where 𝜈 is the total exhaust effective mass flow straight ...
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### How to convert body frame-relative aerodynamic coefficients to wind frame-relative aerodynamic coefficients

I have a rocket flight simulator that takes in aerodynamic coefficients defined relative to the vehicle body frame axes (Cx, Cy, Cz). These are in a lookup table based on mach. I have some aerodynamic ...
92 views

### Is contact between flow and inner walls of nozzle required for thrust generation?

I uploaded a picture below explaining over-expanded flow/nozzle condition with regards to thrust. This aviation source tells that “extra nozzle walls don’t generate any additional thrust because flow ...
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1 vote
92 views

### How can over-expanded flow go out of nozzle when it has less pressure than ambient pressure?

We know that over expansion in flow means that nozzle exit pressure of flow is lower than ambient pressure at specific altitude. It gets narrower while exiting nozzle causing loss in efficiency. My ...
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### What would happen if you tried to take off in a vacuum?

What would happen if the pilot of a pressurized rocket-powered airplane-shaped vehicle attempted to take off in a vacuum? I would expect the plane to just taxi no matter what the pilot did; is this ...
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1 vote
373 views

### Centrifugal force created by a 1045 propeller

I currently am creating a project in which I'm using a 1045 propeller with a BLDC motor that spins at ~16,000RPM. It is powering a single motor "rocket" that basically is configured to carry ...
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744 views

### Why do TFRs for spacecraft launches have ceilings?

When the FAA issues TFRs for spacecraft launches, such as this recent example the restrictions invariably limit their effect up to a certain altitude which never seems to exceed FL180. This is well ...
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### Why astronauts during launch fly faster than jets but experience less Gs? [closed]

The NASA Space Shuttle used to lunch astronauts into spaces at high speeds, supersonic speeds. When you google whats the Gs force they experienced while departing or simply “Gs forces astronauts” You ...
866 views

### Hypothetical Ramjet-Scramjet-Rocket Combination?

Theoretically, could a ramjet-scramjet-rocket combination exist that operations like a rocket for taking off(below operations speeds from the ramjet or scramjet) or in space, and then switch to ramjet/...
4k views

### Propulsion method for MANPADS missiles

What propulsion method is used for small short range handheld missile systems? Liquid fuel rocket engines are the gold standard but I suspect require too many components for the size requirements. Is ...
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1 vote
190 views

### What was the last rocket-plane?

Starting with the legendary Heinkel He 176, these unorthodox planes broke the sound barrier and other records. My question is: What was the last rocket plane to be produced?
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### How to determine the length of the CD nozzle?

I am designing a convergent nozzle as well as a CD(Converging-Diverging) nozzle. How do I find out the length of those nozzles? If the throat of the CD nozzle has 0 length then what should be the the ...
1 vote
120 views

### Why pressure and temperature decreases along the length of a convergent nozzle?

I know that the pressure and temperature follows stagnation relations of pressure and temperature as well as area mach relation inside a convergent nozzle along the length. And according to that ...
3k views

### Why does a rocket engine increase power with speed if the burn rate is constant?

A rocket produces constant thrust with speed, and that means increasing power with speed. Where does this increase in power come from if the fuel burn rate is constant? How can we explain this in the ...
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590 views

### What is the maximum Mach number that can be achieved at the exit of CD nozzle?

I understand that you can get Mach 1 at the throat of a convergent-divergent (CD) nozzle and after that you can have two roots, one is for subsonic and other is for supersonic. Considering the ...
1 vote
460 views

### Why aren't air turborockets used in military fighters?

Why aren't air turborocket engines used in jet fighters? Few Third World countries have the capability to manufacture high quality turbine blades. Thus, why not use air turborocket engines for the ...
4k views

### Why are the grid fins on Starship pointy and sharp?

The grid fins on Starship are serrated, why? Does it help in transonic maneuvers? Source: Starbase Factory Tour with Elon Musk [Part 1], YouTube, at 30:28
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### how missiles or rockets change direction if gyroscopes prevent any direction change? they would bring back the rocket to same path? [closed]

Gyroscopes are instrument which prevent any wobbling or direction change but then how rockets and missiles change their directions. To change direction we have to give signals to gyro or to the servo(...
311 views

### Does/did Russia or the Soviet Union ever fly rocket planes?

Did Russia or the Soviet Union ever have their own experimental or military rocket planes (other than the Buran), or did their military merely use jets and other non-rocket aircraft? America flew ...
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### What should the inlet to throat area ratio be for a CD rocket nozzle on an aircraft flying at Mach 10?

I am analysing a rocket CD (convergent-divergent) nozzle at a altitude of 15,000m. I am stuck on how to calculate the areas so that at the throat of the nozzle Mach number equals to one. The ...
83 views

### When was the first manned rocket-propelled plane launched? [closed]

I believe that it's an issue of some interest in the history of aviation.
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845 views

### What's the highest altitude ever achieved by a (rocket-?)plane for level flight?

As probably most of us know, the SR-71 Blackbird holds the altitude record for leveled flight for (manned) jet planes (and ground-launched planes) at 90,000 ft MSL. However, the very altitude record ...
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### Did every X-15 pilot become weightless when flying into the upper strato- and mesosphere?

The North American X-15 was aimed at breaking airspeed and altitude records. The flights that sought to achieve new airspeed records (Mach 5+) were rather leveled but the flights into the upper ...
126 views

### What valve would be the best for a model rocket with a hybrid engine? [closed]

I am planning on building a model rocket with a hybrid engine. I am trying to find the best valve that could be used for the MOV, main oxygen valve. I plan to use gaseous oxygen and would like the ...
550 views

### How calculate water rocket thrust? [closed]

both nozzle is 2cm diameter one "rocket" has air pump which hold constant 5 bar second "rocket" it has water inside and also air pump which hold cosntant 5 bar,(water column is ...
5k views

### What's wrong in this engine test cell picture from the book 'Ignition'?

This is picture taken from 'Ignition' book by John D Clarke. I am bewildered after seeing picture that I can't find wrong in this picture. I guess this is related to the structure of mach ...
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1 vote
670 views

### Does any engine combine an air-breathing rocket and a non-air-breathing rocket?

Does any rocket engine combine air-breathing and non-air-breathing modes? The advantage would be it would have to carry a smaller tank and less oxygen, leaving more room for payload on a weight basis.
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### What is wrong with my understanding about total pressure for a rocket nozzle?

I’m using the ideal rocket equations and isentropic flow but cannot determine what is wrong in my understanding about total pressure. Can anyone explain where I am wrong using the following example? ...
455 views

### Would "Mad" Mike Hughes' steam-powered rocket have been certified airworthy by the FAA?

Daredevil 'Mad' Mike Hughes died after his homemade rocket crashed on 22 February 2020. The cause appears to be the premature deployment of the parachute used for a safe return. He was hoping to reach ...
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585 views

### Credible Sport Project: Is it possible to revive the idea with modern avionics?

Synopsis: On a secret mission to rescue 52 hostages in Iran, Operation Credible Sport was created. The project consisted of a modified Lockheed C-130 Hercules and developed so that it would be able to ...
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343 views

### Rocket Thrust vs Air breathing jet engine why is a rocket better [duplicate]

What are design dynamics that give the rocket engine higher thrust than an air breathing jet engine of similar size in comparison to a turbo jet engine, turbo fan engine, high by pass turbo fan engine,...
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85 views

### Are solid fuel rocket engines designed differently and how? [closed]

How do solid fuel (Hydrazine, UDMH) and oxidizer (N2O4) differ in design from cryogenic rocket engines such as LH2 and LOX? Are there differences related to temperature, material design, turbopumps, ...
178 views

### Why Apollo 11 was launched in summer? (Performance question) [closed]

The question could seems stupid, but i think that best moment to launch a rocket is when temperature is lowest in order to achieve the best performance in a reaction engine. I do not know if there is ...
977 views

### Could the Space Shuttle take off like an airplane?

This question got me thinking, would the Space Shuttle have been able to use its main engines to roll up to speed and take off horizontally like an airplane? (I'm not asking about getting to space, ...
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741 views

### Why is the center of pressure of a rocket at its centroid?

From thin airfoil theory, at subsonic speeds, the center of pressure of any uncambered airfoil is at quarter chord. For sounding rockets, however, the center of pressure is generally assumed to be ...
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1k views

### At what altitude does a wing become useless? [duplicate]

At what speed or altitude does an aircraft become more efficient as a rocket then a plane using thrust vectoring instead of the wings to steer? At what altitude did the flight control surfaces of the ...
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177 views

### Are the nearby airplanes cleared of the sky when launching Falcon Heavy? [duplicate]

I was checking Flightradar24 when launch occurred and didn't see any difference. Also, 3 boosters landed back successfully. I assume the sky has to be clear of airplanes to avoid any potential ...
829 views

### Why are hexa airfoils used on rockets despite having more drag that diamond airfoils? [closed]

I was doing a study on airfoils shape for a rocket. I tested the diamond and the hexagonal airfoil with Missile DatCom, RasAero and the Shock Expansion theory and from my results it seems like the ...
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370 views

### How can ballistic techniques be used for passenger transport? [closed]

Going anywhere on the globe in half an hour, instead of up to 29 hours, is of course very appealing. How can ballistic technology be used for the purpose? The acceleration is supposed to not exceed ...
61 views

### Are throttleable rocket engines the less efficient the lower the power setting?

Are throttleable rocket engines less efficient the lower the power setting? Logically that would lead to lower pressures in combustion chamber and so lower thermodynamic efficiency. Or is it remedied ...
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417 views

### Can air to air refueling can be done in the rocket engines as done in the Aircraft jet engines?

Can air to air refuelling can be done with rocket engines as is done with conventional aircraft jet engines? If no then what are the possible hazards or conditions preventing this?
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### Why was a Lockheed L-1011 chosen by Orbital ATK for its Pegasus launches?

Not sure whether this fits better here in Aviation, or would be better suited for Space, but since the question is about a terrestrial aircraft, I'll start it out here. The topic of my question is ...
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249 views

### Are there any locations where I could launch a rockoon with minimal red tape?

I'm currently working on a research project on hypersonic control surfaces, and as part of it, I'd like to launch a rocket-assisted lifting body from a high-altitude balloon. Are there any locations ...
2k views

### What is the theoretical maximum speed of a rocket-powered aircraft in the atmosphere?

I read that the scram jet has a theoretical maximum speed of Mach 24. What is the theoretical maximum speed of a rocket-powered aircraft designed to operate in the atmosphere?
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