2k views

### Is there a limit to the possible altitude for electric jets?

So I was thinking about Elon Musk's supersonic electric jet idea. Assuming we have sufficiently energy-dense batteries, where would the limits be in terms of speed and altitude. His logic seems to ...
5k views

### Why are there no Mach 4+ fighter planes?

Why are there no Mach 4+ fighter aircraft? It seems that such aircraft would have massive advantages when it comes to being able to fire longer range missiles and evade return fire.
2k views

### Why does the U-2 Dragon Lady not have swept wings?

Swept wings increase the critical mach number for aircraft with otherwise identical wings (Source 1). The U-2 Dragon Lady is limited in altitude by its critical mach number, as it needs more speed in ...
280 views

### What is the temperature of intake air at several speed of sound intervals from 1x to 10x?

I watched a YouTube movie about Reaction Engines development of the Sabre engine which main feature is cooling intake air. However, I cannot find an overview of the temperature of intake air at ...
4k views

### Which supersonic airplanes use Pitot Air intakes?

Which supersonic (fighter) airplanes use the simple Pitot Air Intakes / Normal Shock Inlets? Two examples already seen here on Aviation.SE (one and two) are Dassasult Rafale ($Ma \leq 1.8$) Image ...
481 views

### What is the maximum Mach number for a titanium aircraft? [closed]

What is the maximum achievable Mach number for a titanium aircraft assuming speed is limited by structural heating? The answer would be even better if there is a list of different materials and ...
3k views

### why are regional cruising altitudes higher than those of international much longer flights?

How come, for example, the average cruising altitude of let's say the Westjet Boeing 737-600 from CYWG to CYVR flies at an altitude of 38,000 feet-40,000 feet, yet the Air Transat Airbus 330-200 ...
6k views

### What are the merits of an inlet cone/spike/centerbody vs. a 2D inlet?

And which is better for a scramjet? Is a 2D inlet basically a "2D cone"? Similar to how an aerospike engine is made "2D" in the linear aerospike? What's inside the cone/spike? Or is it just hollow?
9k views

### Why are many jet aircraft designed to cruise around FL350-370?

If the flight distance permits, the B737-800 will cruise at FL350, the A320 a little bit higher... Flying at FL370. Photo: Live from the Flight Deck by GolfCharlie232 (reframed) Elements such as ...
33k views

### What determines the maximum altitude a plane can reach?

What factors determine the maximum altitude for a plane? Is it limited by wing design, engine thrust, and so on? Is there a formula by which one can calculate the maximum altitude a plane can reach?