Achieving VTOL with jet engine instead of rocket engine

In summary, the T-73 achieves vertical takeoff with an actual jet engine as opposed to the rocket engines used by the majority of jetpack models, allowing it to have longer flight time (9 minutes as opposed to 30 seconds). Some fighter planes also manage VTOL with a jet engine, the most well-known of which is probably the F-35.
  • #1
Mr. Barracuda
3
0
Jetpack International's T-73 achieves vertical takeoff with an actual jet engine as opposed to the rocket engines used by the majority of jetpack models. This allows it to have longer flight time (9 minutes as opposed to 30 seconds). Some fighter planes also manage VTOL with a jet engine, the most well-known of which is probably the F-35.

Most jets aren't powerful enough to achieve vertical takeoff and rockets are usually required. What is it about jetpacks and fighter plane engines that gives them the extra boost in power? I'm guessing a very powerful compressor to intake enough air even when starting from rest?
 
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  • #2
Mr. Barracuda said:
Some fighter planes also manage VTOL with a jet engine, the most well-known of which is probably the F-35.

And not Harrier?
 
  • #3
As always it is a tradeoff.
An engine able to lift the aircraft vertically needs a large intake, which then creates big drag at higher speeds.
The F35B instead achieves VSTOL with a Rube Goldberg engine gear box driven fan built into the middle of the fuselage, with folding doors to cover it in forward flight. It is hugely costly in terms of payload and performance, but probably the only acceptable way to combine supersonic capability with VSTOL.
 
  • #4
etudiant said:
The F35B instead achieves VSTOL with a Rube Goldberg engine gear box driven fan built into the middle of the fuselage, with folding doors to cover it in forward flight.

In the beginning ...
https://www.youtube.com/watch?v=f8W2SI4c93s
 
  • #5
Great footage, AlephZero!

The US Army was very active in the 1950s in the pursuit of VSTOL, with a whole series of experimental airplanes and devices. None was able to match the helicopter for overall effectiveness and none went into production.
The USAF did have an effort with West Germany in the 60s to develop a supersonic VSTOL fighter bomber with dedicated lift engines placed in wing tip pods.
The dead weight of the VSTOL propulsion and the cost of qualifying the lift engines killed that project.
But the siren song of VSTOL has clearly caught the USMC leadership in its spell, even though it is of questionable cost/effectiveness.
 
  • #6
The goals of speed and lift are opposites of each other for engines, so that makes it difficult for jet engines. Lifting works best with a high volume at low velocity (which is why helicopter rotors are so large) while speed works best with a high velocity at low volume.
 

FAQ: Achieving VTOL with jet engine instead of rocket engine

How does achieving VTOL with a jet engine differ from using a rocket engine?

Achieving VTOL (Vertical Take-Off and Landing) with a jet engine differs from using a rocket engine in several ways. Jet engines use the principle of air propulsion, where air is sucked in, compressed, and then ignited with fuel to create thrust. This allows for continuous propulsion, while rockets use stored propellant that is burned to create thrust in a single burst. Additionally, jet engines have the ability to vary their thrust, making them more versatile for VTOL maneuvers compared to rocket engines.

What are the advantages of using a jet engine for VTOL instead of a rocket engine?

Using a jet engine for VTOL has several advantages over using a rocket engine. Jet engines are more efficient and require less fuel, making them more cost-effective. They also have the ability to hover and perform vertical maneuvers, which is not possible with rocket engines. Jet engines are also safer and more reliable, as they have multiple redundancies and can be shut down or restarted during flight.

Are there any limitations to achieving VTOL with a jet engine?

While jet engines have many advantages for achieving VTOL, they do have some limitations. Jet engines require a certain amount of air to operate, so they are not suitable for use in space or in areas with low air density. They also have a lower maximum thrust compared to rocket engines, which may limit their capabilities for certain applications.

How is the technology for achieving VTOL with a jet engine currently being used?

The technology for achieving VTOL with a jet engine is currently being used in various aircraft, such as helicopters, tiltrotors, and some military jets. The most well-known example is the Harrier jump jet, which uses a jet engine with movable nozzles for vertical take-off and landing. Companies are also currently developing new technologies, such as vectored thrust engines and hybrid-electric propulsion systems, to further improve VTOL capabilities with jet engines.

What are the potential future advancements in achieving VTOL with a jet engine?

There are many potential future advancements in achieving VTOL with a jet engine. One possibility is the development of more efficient and powerful jet engines that can provide greater thrust for improved VTOL performance. Another advancement could be the integration of new technologies, such as artificial intelligence and advanced navigation systems, to enhance the precision and control of VTOL maneuvers. Additionally, the use of alternative fuels, such as hydrogen or electric propulsion, may also play a role in the future of achieving VTOL with jet engines.

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