Questions tagged [high-altitude]

Regions on or above the earth's surface located at least 2,400 meters (8,000 ft) above sea level.

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98 views

What limits high altitude powered paragliders other than the engine?

Due to their extremely low wing loading, powered paragliders stall at very low indicated airspeeds compared to other airplanes. A typical paraglider can continue flying all the way down to 10-15 ...
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131 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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1answer
156 views

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 ...
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1answer
156 views

Are there jet aircraft for whose flights astrodynamics must be taken into account? [duplicate]

Civilian jet airliners don't need to push their yokes down to follow the curvature of the Earth because within the atmosphere the curvature is accounted for by automatical systems, right? I wonder ...
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1answer
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Could one see stars from the Concorde in daytime?

The Concorde flew to an altitude of 60,000 ft (18.3 km) where stars should be visible at noon, aren't they? This question asks on how high stars become visible, and it is said Blackbird pilots could ...
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How is altitude reached by aircraft flying above the stratosphere measured?

Aircraft flying above the stratosphere (above 30km) are rare, but there is still the X-15 and the spaceship two. For those aircraft, maximal altitude is measured to within 500 ft. As described in this ...
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303 views

What is the maximal altitude at which an emergency slide can be deployed?

If I understand correctly, the mechanism to inflate an emergency slide relies on a tank of inert gas and on an "aspirator" that sucks ambient air. This aspirator works thanks to depression ...
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1answer
115 views

How does 'standalone' propeller efficiency change with altitude?

I've seen questions regarding propeller aircraft and altitude and their interaction. But I'm wondering what the relationship between just the propeller and altitude (changing air density) is. How does ...
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1answer
247 views

What happens in an F-16 once the aircraft exeeds its service ceiling?

What exactly is the sequence of events that would unfold as an F-16 attempts to exceed its service ceiling? The scenario is simply full afterburner and attempting to simply climb higher and higher (at ...
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3answers
165 views

What happens if an aircraft goes above maximum altitude? [duplicate]

We all know what happens when a plane goes overspeed... but what happens when a plane goes above their max. altitude? And why are planes certified maximum altitudes anyway? Is it because there won't ...
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148 views

How to adjust time of useful consciousness for pilots acclimatised to high altitudes?

The time of useful consciousness (TUC) is the length of time an average pilot, breathing ambient-pressure air without supplemental oxygen, is capable of functioning usefully at a given altitude. For ...
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1answer
369 views

Does high density altitude affect your landing speed?

So I had this question asked in my recent commercial-pilot checkride: The DPE asked me about high-density-altitude airports; he specifically asked me if I should add airspeed when I'm on landing ...
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Which aircraft can fly at FL600 or above?

I would like to know some examples of aircraft (specific models) which can fly at FL600 or higher. I am interested in aircraft which can or could fly at that altitude on a regular basis (service ...
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How does latitude affect the air temperature at 8 km altitude where planes fly?

Is the air temperature (at 8km) above the North or South poles colder than the same altitude above the equator? Why? Ground level air temperature difference between coldest and warmest places on ...
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1answer
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Do the Mt. Everest rescue helicopters have modified engines to operate at high altitudes?

There are so many climbers on Mt. Everest today that there is now a helicopter rescue service there. They operate rescue up to 21,000 + ft. Because this is essentially stationary service it seems that ...
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1answer
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Where and when would a 737-700 be taking off at an altitude of 19 kft?

Another question triggered by reading the 737 technical site; according to this section of the page on the 737's pressurisation system, the 737-700 comes with an option that allows it to safely take ...
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633 views

What kind of drone might be able to fly so high that it “operate(s) outside national boundaries”?

In the question What is a propellant burner trailer? I mention that CNN and NPR have pointed out that the US president recently tweeted a surveillance photo of an explosion of a rocket on a launch ...
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4answers
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Why do private jets such as Gulfstream fly higher than other civilian jets?

I heard in a TV show that private jets such as Gulfstream can fly at about 50,000 ft, higher than other civil jets. Is it an aerodynamic reason (lighter aircraft to be sustained in a less dense air) ...
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Could a hybrid electric steam plane be more efficient at altitude than at sea-level, and how to optimise it to frigid air?

In the thirties a steam powered plane was built. video Could a hybrid electric steam plane be more efficient at altitude than at sea-level, and how could such a steam engine be optimised to benefit ...
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How do carbureted and fuel injected engines compare in high altitude?

I couldn't find enough information on the internet for this topic. What I found can be paraphrased as: Carburetor means easy engine start while fuel injected means manual fuel start up and ...
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What lights to use for a high-altitude weather balloon?

I am designing a high-altitude weather balloon for a college project. The balloon may fly at night, which means that, per FAA regulations, I need a light that is visible for 5 miles. Does anyone ...
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1answer
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Proportionally, what is more affected by a hot and high takeoff - a electrically driven propeller or a turbofan?

My assumption would be the electrically driven propeller would be less affected compared to turbofans at high altitudes and take off as although the air would be less dense at these ambient conditions,...
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How do planes know what altitude they're cruising at?

I know that when planes enter the aerodome containing the airfield of destination, the ATIS will tell them an altimeter setting so the system knows how to calculate their altitude above their field; ...
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What will happen to a modern high bypass engine at 80 000 feet with cruise speed of 0.8 Mach?

While keeping the typical cruise speed of 0.8 Mach, will the engine shut down due to "air starvation" at such high altitude? Is it possible to design a turbofan engine, which is able to provide thrust,...
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Has fuel boiling ever been an issue for high altitude aircraft?

Are special measures being taken to prevent fuel from boiling inside the fuel systems at high altitudes? If so, when (with what aircraft) did this practice start? (question is pertaining to air-...
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1answer
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Difference between Mach buffet and shock stall

What is the difference between Mach buffet and shock stall?
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361 views

Why do suborbital planes feature H-tail and/or large wingtips?

Spaceplanes that are suborbital are mostly supersonic and feature H-tail or rather large wingtips. This looks to be similar to a H-tail configuration but I'm unsure abut how it works, which is why I ...
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Why does aircraft stability increase when it transitions from subsonic to supersonic flight?

I am puzzled why would the aircraft be more stable at high speed flight at high altitudes. Given that the Centre or Pressure moves gradually towards the 50% MAC region, once past Mcrit. Has this got ...
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2answers
846 views

What forces act on an airplane's door from the outside in cruise?

The inside cabin pressure from what I understand is pressurized to the values found at 6000-8000 feet high (11.34 psi at 7000 feet), at which point we can find the amount of force can be found acting ...
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1answer
147 views

Why do high altitude air-launch plane designers choose to use two fuselages?

We see double fuselages in both the huge Stratolaunch vehicle and in Virgin Galactics high altitude launch vehicle. What about this design makes it desirable?
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If maximum speed was a priority for modern military fighter jets and bombers, approximately how fast would they likely be?

Burt Rutan talks rather passionately about the lack of innovation in space flight, but also mentions how fighter jet (maximum) speed performance has stalled: In fact,...
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1answer
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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 ...
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365 views

What special tyres (tires) are needed for high altitude takeoff and landing?

I just watched this video of AA922 taking off from El Alto (LPB) to Santa Cruz. The video's author mentions that the aircraft needs "... special tyres" due to the high altitude. While I do ...
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1answer
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What is the highest operational ceiling for an air-breathing jet engine?

An air-breathing jet engine can only operate at relatively low altitude, where the atmosphere is dense enough. However, some jet-powered aircraft can operate at an altitude higher than 20 Km (e.g., ...
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6k views

Is there a height limit to national airspace?

Given the following facts: satellites can operate at an altitude of 200km without triggering frontier violation incident aircraft can trigger diplomatic protestations if they cross a frontier at an ...
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2answers
530 views

Could an airliner get better fuel efficiency at higher altitude? [duplicate]

By higher I mean like 60k feet instead of 30k. Seems like the rate limiting step is engine performance at 60k feet. Are people working engines that can operate at higher altitudes? How close are we ...
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1answer
175 views

Are artificial magnetic fields used or proposed to be used to shield high altitude pilots and astronauts from charged, high energy radiation?

If not for the earth's magnetic field our atmosphere would be bombarded by high energy plasma (ionized gas) from the sun and other space sources. At very high altitudes and orbital altitudes this ...
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What are the limiting factors for high altitude planes (e.g: U2 or SR71) preventing them from going higher?

I'm curious as to why planes like the U2 Dragon Lady and the SR71 Blackbird couldn't fly higher. What physical constraint set their operational ceiling? Pilots wore spacesuits, so that wasn't the ...
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Why is the ratio of TSFC at altitude vs. sea level different for hi-bypass vs. lo-bypass turbofan engines?

I've read up on how the thrust-specific fuel consumption of turbofan/turbine engines increases with altitude, and the Georgia Institute of Technology plot in particular seems to indicate that, for ...
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Which small, light aircraft are suitable for operating at very high elevations?

I live in Jammu and Kashmir, in an area with an average elevation of 4,500m / 14,700ft MSL . I would like to know what would be a good and cheap light aircraft to carry 3-4 people for a 3-4 hour ...
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922 views

Why is tethered hover testing performed on helicopters?

The KGUC website notes that they have a tether for helicopter testing. From what I can tell this testing has something to do with hot and high conditions, but I don't know what the purpose is of ...
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What is a blimp called if it is designed not to be lighter than air?

I have not found a name for a this type of vessel what class a vessel is it? Could it operate similar to a parasail if dropped from a high altitude or orbit with air far thinner then operational ...
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What are the ground and flight requirements for high performance endorsement?

I'm told ground is proficiency based but that in the plane you have to fly up to 25,000 feet! I don't know anything short of a turboprop capable of doing that, let alone have the ability to rent it. I'...
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Can a light glider without thermal protection land from the orbit, starting from the orbital speed?

I ask about a glider without any special thermal protection (pilot in the space suit), so both answers to the other question do not cover the topic. When the glider enters the atmosphere, it starts ...
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3answers
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Could a plane with an electric turbine engine generate enough lift to provide a electric areodynamic lift and runway to space?

This question is similar to my previous ones but configuration is different and so is the question. Could a modified electric turbine engine (E-Fan) plane create enough of its own lift not to burden ...
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4answers
847 views

Is it possible for a modified hang glider to land safely coming from orbit? [closed]

Can a glider be dropped from geosynchronous or other orbits and safely land?
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2k views

Is there a maximum airfield elevation in which a Cessna 172P can operate?

The title says it all: is there a maximum airfield elevation in which a Cessna 172P can operate? Or a maximum density altitude at which take off shouldn't be considered?
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1answer
728 views

Passenger hypoxia in a small plane at 11,000 feet: what is the pilot's responsibility?

An acquaintance of mine visiting western U.S. was recently a guest passenger in a small plane flying from Santa Fe, New Mexico to Colorado reaching an altitude of 11,000 feet. She related that she ...
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743 views

Do airliners adjust altitude for latitude?

According to this NASA article, the troposphere extends from about 5 miles at the poles to about 9 miles at the equator. Though the height of the troposphere is defined by the height of the tropopause ...
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2answers
4k views

How are aircraft separated at high altitude?

When cruising at high altitude, a fixed-wing aircraft has less margin for adjusting its speed, due to the convergence of the stall "speed" and the overspeed limit: If and aircraft has to be separated ...