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15 votes
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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 ...
ericksonla's user avatar
12 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 ...
William Walker III's user avatar
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 ...
Olin Lathrop's user avatar
  • 11.4k
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 ...
Surprised Seagull's user avatar
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"/"...
SF.'s user avatar
  • 6,105
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.
Andy's user avatar
  • 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 ...
Andrew's user avatar
  • 766
4 votes
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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/...
DLS3141's user avatar
  • 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. ...
SF.'s user avatar
  • 6,105
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's user avatar
  • 1,981
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 ...
niels nielsen's user avatar
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 ...
Dan Mills's user avatar
  • 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 ...
Dan Mills's user avatar
  • 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 ...
Solar Mike's user avatar
  • 15.9k
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 ...
Solar Mike's user avatar
  • 15.9k
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 ...
Fred's user avatar
  • 9,687
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 ...
cmholm's user avatar
  • 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. ...
StainlessSteelRat's user avatar
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 ...
niels nielsen's user avatar
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 (...
Tomáš Létal's user avatar
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 ...
Jonathan R Swift's user avatar
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 ...
Transistor's user avatar
  • 10.9k
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 ...
Phil Sweet's user avatar
  • 4,765
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 ...
Hobbes's user avatar
  • 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 ...
SF.'s user avatar
  • 6,105
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. ...
a rocket amateur's user avatar
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 ...
Phil Sweet's user avatar
  • 4,765
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 ...
mart's user avatar
  • 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 ...
Nefira's user avatar
  • 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. ...
Phil Sweet's user avatar
  • 4,765

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