Is the Dangers of the Downwind Turn real? : ruclips.net/video/RJgQ6qHUGW4/видео.html Which climb Speed is the Safest in a Light Airplane? : ruclips.net/video/qh4C9gfo0W8/видео.html 5 Huge Problems with Electric Planes Everyone is Ignoring : ruclips.net/video/9QlRdkbVPC8/видео.html
The bulkheads on the belly of the Harriers are here to trap some of the air cushion to enhance ground effect. If I remember correctly, early on, pilots noticed that the 2 gun pods made for much smoother handling during vertical takeoffs and landings, so these bulkheads were fitted when the gun pods were not in place.
Helicopters are technically designated as "Rotary Wing" aircraft, and the shape of the helicopter rotors are more akin to a wing than a propeller. Hence, even the "Ground Effect" argument of being within half the wingspan of a "fixed wing" aircraft still holds true as you said as it is within half the rotor diameter ("wingspan" of a rotary wing) of the helicopter. I should also point out that the research on the Rolls Royce Pegasus engines that power the Harrier, Harrier II, and the Sea Harrier seems flawed. The Pegasus has 4 exhaust nozzles. The 2 forward nozzles are the "Cold" nozzles as they direct the Turbofan bypass air directly out of the aircraft. The 2 rear nozzles are the "Hot" nozzles as they direct the hot exhaust after the combustion section of the engine out of the aircraft. There is no real mixing of cold bypass and hot combustion exhaust as on the F414 engine used as the example. That is more true of the F=35B and its Pratt & Whitney F135 engine. The F135 has a PTO to drive the forward downward ducted fan of the F-35B, and the exhaust of the engine is similar to the F404 engine. However, air is also bled from the bypass to provide stabilizing jets on the starboard and port sides near the wing roots. To clarify, this is ONLY true on the F-35B which is the STOVL version of the F-35 series of aircraft. It should be noted that both the Harrier series, and F-35B STOVL aircraft do cause damage to the their landing pads if they exceed a certain amount of time hovering over their landing pad. The Royal Navy carriers operating the F-35B have designated landing areas for the aircraft, which are treated with a heat resistant coating within that area. Temperatures of the F135 engine is much higher than that of the Pegasus engine. BTW, propellers were once called "air screws" much like how propellers on boats & ships are referred to as "screws."
What about the surface area "exposed" to the high pressure zone? An helicopter, a propeller plane flying close to the ground and the harrier all have their entire undersides exposed to the high pressure zone, so that high pressure air has a large section of the aircraft to "push" against. On the other hand, if the high pressure zone is created behind the plane, that's a really small area that the air can't "push" against nearly as effectively.
Unrelated, but I thought of this while watching. Fluids always from from high to low pressure. If the combustion chamber of a jet increases pressure out the back, how does it keep the flow from going backwards?
I think while your conclusion is most likely right your explanation for why JBD don´t increase thrust is wrong. It`s more about the distance to the wall/JBD making any effect negligible. If a wall was placed close to the exhaust the pressure at the exhaust would be higher, therefore increasing thrust
Actually, it would compressor-stall the engine. This is what happens when that same F-14 "tail slides" and falls straight backward. Simply incoming air from the wrong direction even at relatively low speeds will snuff them out.
Is the Dangers of the Downwind Turn real? : ruclips.net/video/RJgQ6qHUGW4/видео.html
Which climb Speed is the Safest in a Light Airplane? : ruclips.net/video/qh4C9gfo0W8/видео.html
5 Huge Problems with Electric Planes Everyone is Ignoring : ruclips.net/video/9QlRdkbVPC8/видео.html
The bulkheads on the belly of the Harriers are here to trap some of the air cushion to enhance ground effect. If I remember correctly, early on, pilots noticed that the 2 gun pods made for much smoother handling during vertical takeoffs and landings, so these bulkheads were fitted when the gun pods were not in place.
Harrier maintainer here: The nomenclature for the part you are talking about is called a ventral strake
Helicopters are technically designated as "Rotary Wing" aircraft, and the shape of the helicopter rotors are more akin to a wing than a propeller. Hence, even the "Ground Effect" argument of being within half the wingspan of a "fixed wing" aircraft still holds true as you said as it is within half the rotor diameter ("wingspan" of a rotary wing) of the helicopter.
I should also point out that the research on the Rolls Royce Pegasus engines that power the Harrier, Harrier II, and the Sea Harrier seems flawed. The Pegasus has 4 exhaust nozzles. The 2 forward nozzles are the "Cold" nozzles as they direct the Turbofan bypass air directly out of the aircraft. The 2 rear nozzles are the "Hot" nozzles as they direct the hot exhaust after the combustion section of the engine out of the aircraft. There is no real mixing of cold bypass and hot combustion exhaust as on the F414 engine used as the example.
That is more true of the F=35B and its Pratt & Whitney F135 engine. The F135 has a PTO to drive the forward downward ducted fan of the F-35B, and the exhaust of the engine is similar to the F404 engine. However, air is also bled from the bypass to provide stabilizing jets on the starboard and port sides near the wing roots. To clarify, this is ONLY true on the F-35B which is the STOVL version of the F-35 series of aircraft.
It should be noted that both the Harrier series, and F-35B STOVL aircraft do cause damage to the their landing pads if they exceed a certain amount of time hovering over their landing pad. The Royal Navy carriers operating the F-35B have designated landing areas for the aircraft, which are treated with a heat resistant coating within that area. Temperatures of the F135 engine is much higher than that of the Pegasus engine.
BTW, propellers were once called "air screws" much like how propellers on boats & ships are referred to as "screws."
Another interesting offering!
Thanks for the video. On the Harrier, the front nozzles direct cold bypass air. The rear nozzles direct hot exhaust gases.
What about the surface area "exposed" to the high pressure zone?
An helicopter, a propeller plane flying close to the ground and the harrier all have their entire undersides exposed to the high pressure zone, so that high pressure air has a large section of the aircraft to "push" against. On the other hand, if the high pressure zone is created behind the plane, that's a really small area that the air can't "push" against nearly as effectively.
The difference in pressure is only a few millibars.
Because you cannot pressurize and open area exposed to the entire atmosphere on all sides.
Unrelated, but I thought of this while watching. Fluids always from from high to low pressure. If the combustion chamber of a jet increases pressure out the back, how does it keep the flow from going backwards?
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But the harrier still has much highest exhaust speed than the GA plane, so why doesn't the GA plane have the same effect?
Well done. TY
I think while your conclusion is most likely right your explanation for why JBD don´t increase thrust is wrong. It`s more about the distance to the wall/JBD making any effect negligible. If a wall was placed close to the exhaust the pressure at the exhaust would be higher, therefore increasing thrust
Actually, it would compressor-stall the engine.
This is what happens when that same F-14 "tail slides" and falls straight backward. Simply incoming air from the wrong direction even at relatively low speeds will snuff them out.
That's exactly what I believed too, and why I said the same thing in a previous video.