14
votes
Accepted
Can a water-pump pump diesel?
With pumping diesel, your main constraint should be safety, not cost. There are very good reasons diesel pumps aren't for sale for $5 on amazon.
The main things you want to look at are 1) whether ...
- 762
11
votes
Accepted
Why do rockets not fly straight up after launching; wouldn’t that be less atmosphere to traverse?
Since orbiting isn't about altitude, but is instead about velocity (orbiting is the art of throwing yourself at the ground, and missing because you're going sideways so fast), the final goal is to ...
6
votes
Are rocket engines practical for commercial aircraft?
At a fundamental level, it should be clear that throwing stuff out the back is going to be less economical than sucking in stuff in the front and throwing it out the back faster. For one thing, the ...
- 11.5k
5
votes
Why are rocket engines tested horizontally?
Most of the time during a rocket's flight, it and it's exhaust are far away from the ground. So the engine is optimized for this mode, when there is no exhaust reflection off the ground.
If the engine ...
5
votes
Accepted
the speed of the exhaust
He refers to Tsiolkovsky's Rocket Equation:
$$ \Delta v=v_e \ln {\frac {m_0}{m_f}} $$
where:
$v_e$ is the exhaust velocity;
${\frac {m_0}{m_f}}$ is the fraction of mass; $m_f$ - the "dry mass"/"...
- 6,115
4
votes
Accepted
What is the purpose of building multistage rockets, rather then packing more fuel into a single stage?
As the rocket is propelled upwards, it expends fuel. So there is no need to carry half empty fuel tanks. By splitting it up into separate stages, you can simply drop off unneeded mass.
- 110
4
votes
Are rocket engines practical for commercial aircraft?
Economically a rocket engine will always lose out to a jet engine.
We'll ignore solid fuel rockets, they are impractical for commercial air travel due to their fixed thrust and inability to turn on ...
- 766
4
votes
Accepted
Propane rocket nozzle material
The answer is that in order to survive and function, the rocket nozzles need to be cooled. How that's done varies with the application, but includes:
Liquid Cooling Jacket: The liquid propergols and/...
- 2,145
4
votes
Small oxygen tanks
First, if you plan to use the same tank for flight and storage, that's not a good approach, because the tank to last without leaking, corroding, or being at risk of damage, needs to be quite thick. ...
- 6,115
4
votes
Rocket vs aeroplane? Difference in take off?
A plane relies on aerodynamic lift to stay airborn. This is much more efficient than using raw vertical thrust like a rocket does. The downside is that planes always need to be moving perpendicular to ...
Drew♦
- 2,141
3
votes
Multiple vs single rocket engine nozzles
In strictly practical terms, the quickest solution is to derive a good design for the small engine and then simply add more of them. Scaling up a rocket nozzle is a difficult process (lots of ...
- 15.3k
3
votes
Small oxygen tanks
Why are you trying to use O2 stored as a gas in a rocket?
To get any real quantity of the stuff you would need enormous pressures which argues directly against a light weight tank, the tank ...
- 251
2
votes
Propane rocket nozzle material
To answer the other part of your question, the temperature is that in the chamber, but note that that figure assumes perfect combustion, which may not be the optimum point for specific impulse in your ...
- 251
2
votes
the speed of the exhaust
"the fraction of its mass that the rocket loses as it accelerates" means that assuming the power delivered is constant, the total mass of the rocket decreases as the fuel is spent, therefore altering ...
- 16k
2
votes
What is the purpose of building multistage rockets, rather then packing more fuel into a single stage?
Another reason is that each motor stage can be designed for different purposes to match the flights characteristics.
So, a relatively short high thrust burn to escape gravity
And a longer or ...
- 16k
2
votes
Accepted
How does a nuclear powered rocket engine work?
In Nuclear Thermal Rockets (NTRs)
the heat from a nuclear reaction replaces the chemical energy of the propellants in a chemical rocket. In an NTR, a working fluid, usually liquid hydrogen, is ...
- 9,752
2
votes
Is There A Schematic of Hoeltzer's Mischgerät V2/A4 Electronic Guidance Computer?
I've extracted a reasonably complete description and schematic from the document "Das Gerät A4 Baureihe B Gerätbeschreibung" (The A4 Device Series B Device Description) published by the ...
- 176
2
votes
Why does BlueShift Aerospace Launch from Maine?
From Stardust Generation 1 — bluShift Aerospace:
Stardust 1.0
Basic testbed launch vehicle for experiments requiring subjection to the vibrations and accelerations of launch and parachute recovery. ...
- 2,497
2
votes
What are the limits on plane speed?
For very high speeds in air (~3000 MPH), aerodynamic heating is severe and the limiting factor on speed is the temperature of the body at which it begins to lose strength. This is why ordinary rockets ...
- 15.3k
1
vote
Accepted
Rocket Nose Cone Design ,Ogives,technical drawings are not understood
It can be drawn if the segments are not tangential to each other.
If you want tangential transition, you can define it just between the spherical cap and second segment if the cap is not hemisphere (...
- 1,460
1
vote
Accepted
Fin airfoil holder design and technical drawings not understood
You can see in the rightmost view of the drawing that the R1.32 does not meet a spherical surface as suggested by Transistor, but in fact meets the vertical extension of the cylindrical surface ...
- 7,771
1
vote
Fin airfoil holder design and technical drawings not understood
As I commented, I can't make much sense of the original drawing.
Regarding the fin photo, it's not clear from the single photo if the bulbous area is spherical or not. If so then a revolve and fillet ...
- 11.1k
1
vote
Why do rockets not fly straight up after launching; wouldn’t that be less atmosphere to traverse?
Yes, but atmospheric drag is nearly negligable.
To get into orbit, the rocket has to expend energy doing several different things, and they each have performance constraints that affect the structural ...
- 5,105
1
vote
Rocket vs aeroplane? Difference in take off?
Vertical-takeoff aircraft do exist. A lot of research has gone into this (mainly in the 1960s), but it all led to one conclusion: there's no commercial case for vertical-takeoff jet aircraft.
Only 4 ...
- 746
1
vote
Inefficiency of intermittent burn in rockets
Yes, the efficiency would be worse.
The engine performs optimally when operating at the nominal chamber pressure. The time between engine ignition and it reaching the nominal chamber pressure varies ...
- 6,115
1
vote
What are the design trade-offs in the different rocket engine cycles for liquid propulsion systems
Disclaimer: I am not professional rocket scientist, information is primarily gathered through internet. This answer is provided with NO warranty.
This answer mainly focuses on liquid fuel engines.
...
1
vote
Why is Rocket Nozzle CFD done in 2D instead of 3D?
It isn't really done in 2D. It is done in pseudo 3D. The actual annular areas are factored in. It is primarily based on a uniformity assumption that the gas dynamics are the same all around the nozzle ...
- 5,105
1
vote
Liquid Rocket Plumbing and Instrumentation Diagram: Standards and Presentation
The term is piping and instrumentation diagramm, though plumbing sounds cute. I've never done rocket science so maybe there's conventions I'm not aware of here, but I often work with P&ID in plant ...
- 4,791
1
vote
Combustion Chamber Back Pressure due to gas injection
I believe that the Borda-Carnot equation is only valid for incompressible flows, while you mention that the injector orifice is choked. While the flow becomes incompressible pretty quickly after the ...
- 21
1
vote
Increase thrust of ion thruster?
Only by increasing the area of the emitter. For a given species, you can't increase the density of the mass flow beyond a certain limit. And that limit decreases if you lower the emitting velocity. ...
- 5,105
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