TV of Hornet behind Hercules - Wake Turbulence?
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TV of Hornet behind Hercules - Wake Turbulence?
Melbourne TV Channel 9 showed a beautiful shot of an RAAF Hornet formating on a Hercules and sitting just a few metres behind the Herc's open ramp. Despite being that close the Hornet was clearly unaffected by the Hercules wing tip vortices or propeller slipstream. Years ago I saw a picture of a USAF Hercules flying between to tall masts from which emanated coloured smoke. The wing tip vortices from the Hercules were shown in colour quite dramatically and was proof of the presence of vortices. That being so, I wonder why the RAAF Hornet was unaffected behind the Hercules over Melbourne, today.
Evertonian
Saw that from my "lofty" office in the CBD. Didn't see the footage but from the angle I saw, he wasn't lined up, centre d on the Herc's fuselage. Initially I thought the Hornet was "hooked up" for fuel, but the angle he had it was quite impressive...trying not to "dock" with the aft cabin on the Herc must be fun.
I guess the sheer power of the twin F404's would negate the vortices rather niftily too!
I guess the sheer power of the twin F404's would negate the vortices rather niftily too!
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You knucks just can't help yourselves, can you? control snatch, the guy was just asking a question. How about 'you just deal with it' and explain it nicely.
Cheers,
NFR.
Cheers,
NFR.
I've flown close-ish form behind a Herc as part of a gaggle of PC-9s for photo purposes - when in behind the fuselage, as you might expect, there weren't any dramas, but when manoeuvering out wider, definitely got thrown round a bit, nothing too startling though.
Evertonian
I think it was the cameraman hanging out the back door that was screaming.
Pretty mixed bag under the wings there...no wonder he's listing to the port side a bit...
Pretty mixed bag under the wings there...no wonder he's listing to the port side a bit...
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Tip vortices don't develope into decent wake turbulence until a fair way behind an aircraft (they're too tight to start with). Also a straight winged aircraft like a Herc doesn't give off as much turbulence as a swept wing aircraft of the same mass. Couple that with the high wing loading and exceptional roll capability of something like a Hornet, and it's doable.
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Wake Vortices
The wake vortices of a large transport aircraft definitely do have the capacity to throw a fighter around. However, the effects are generally limited to the outboard wing area, and only when fairly close to the plane of the wing. Line astern is completely free of these effects. In distant history, a RAAF Hornet was 'thrown' over the tail of a B707 by the wing tip vortices (ended up almost inverted behind the opposite wing from which it started!).
Generally, when sitting in the correct tanking position behind a wing mounted refuelling pod, you will need some outboard aileron trim to counter the effects of the vortices which you are generally positioned right on the edge of.
Generally, when sitting in the correct tanking position behind a wing mounted refuelling pod, you will need some outboard aileron trim to counter the effects of the vortices which you are generally positioned right on the edge of.
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Can I also join in in saying the same thing?
The wingtip vortices are found aft of the wingtips. The Hornet, as you said, was near the ramp. No wingtip vortices to be found at the ramp because there are usually no wingtips there.
Also, the turbulence "streams" aft at a higher plane than that which the Hornet is occupying, thus his smooth flight.
At least, there are no vortices from the camera ship the Hornet is following - but there could be another Herc in front of and offset to the camera ship... ha, you never thought of that, did you???
I do approve of your use of the correct terminology - 'vortices' - rather than 'vortexes' as many of our less-learned professional aviator friends seem to prefer.
The real issue is why these planes were sent up at great expense to the taxpayer to do nothing more more than lark about taking photos. These RAAF pilots obviously take great delight in flitting around the skies in their - our - planes having a jolly. And over the city?? What about the noise?
Absolutely disgraceful waste of money.
The wingtip vortices are found aft of the wingtips. The Hornet, as you said, was near the ramp. No wingtip vortices to be found at the ramp because there are usually no wingtips there.
Also, the turbulence "streams" aft at a higher plane than that which the Hornet is occupying, thus his smooth flight.
At least, there are no vortices from the camera ship the Hornet is following - but there could be another Herc in front of and offset to the camera ship... ha, you never thought of that, did you???
I do approve of your use of the correct terminology - 'vortices' - rather than 'vortexes' as many of our less-learned professional aviator friends seem to prefer.
The real issue is why these planes were sent up at great expense to the taxpayer to do nothing more more than lark about taking photos. These RAAF pilots obviously take great delight in flitting around the skies in their - our - planes having a jolly. And over the city?? What about the noise?
Absolutely disgraceful waste of money.
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The real issue is why these planes were sent up at great expense to the taxpayer to do nothing more more than lark about taking photos. These RAAF pilots obviously take great delight in flitting around the skies in their - our - planes having a jolly. And over the city?? What about the noise?
And better yet, I'm being paid to do this sort of stuff.
Careful, your chip's showing.
Evertonian
No wingtip vortices to be found at the ramp because there are usually no wingtips there.
Okay, I'll probably get a right RAAF flaming for this but... what, if any, vortices would be produced by the tail section? I guess the sheer area of the main wing is the cause of the vortices but, would there be any off the tail, or would the fuselage negate it, or is it just plain insignificant?
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the sheer area of the main wing is the cause of the vortices
Formed, regardless of the area of the wing, from the disparity between the high pressure below the wing and the low pressure above the wing as the air escapes the one in search of the other, in a circular movement.
The ramp area just causes what we in the industry refer to as "tur-bu-lence".
Once again, the money-wasting knuck was clearly flying our plane well below the affected area. Proof that our money spent on his training was not wasted, unlike the money spent on this gay, jolly flight of fancy around the city.
I hope he really enjoyed himself, flying his - our - plane around the skies like that.
Evertonian
Poorly phrased by me... ...the vortices that have a significant effect on the trailing aircraft would be proportional to the size/area of the wing? Or do you mean that the vortices' from the tail could have the same effect???
That sounds like, what we on the ground refer to as, "ree-dick-you-less"!
...the vortices that have a significant effect on the trailing aircraft would be proportional to the size/area of the wing? Or do you mean that the vortices' from the tail could have the same effect???That sounds like, what we on the ground refer to as, "ree-dick-you-less"!