Flying techniques in extremis...

[Cacophonix]

While I am just getting my addled noodle around concepts like "rolling/running" take offs it is difficult to imagine techniques such as this one described by Neall Ellis as used in his time flying Mi-8, 17,18 and 24's in Sierra Leone...

I recall some of those take-offs from the football field inside the military camp where we would land. Juba was a brilliant pilot who had spent a lot of his professional career flying chopper gunships in Angola and elsewhere. Self-taught, he’d learned to fly the Mi-17 very well indeed. He ended up teaching me a trick or two, which I applied to my work in other contract areas when we were overweight on take-off or there weren’t any decent runways or areas for take-off. He demonstrated a technique for taking off from a field the size of a football pitch that could be surrounded by high-tension wires, 20 metres high. He’d go into the hover using ground cushion and then slowly reverse back to the furthest point downwind of the field, where he’d initiate a positive move forward. He’d go on doing that to the point where we lost the ground cushion effect and translational lift and that would effectively allow the Hip to descend. At the same time, he’d pull maximum collective and would allow downward movement to the ground to continue. Together with forward speed, he would compress the oleos, which would cause the helicopter to bounce back into the air and, at the same time, pass through transition. The helicopter would accelerate while climbing out of the LZ and clear the wires. It was all very hairy the first couple of times, because once committed nothing would prevent the chopper from striking any of the obstacles if all that didn’t succeed. However, once mastered, the technique was sometimes the only way to clear confined areas safely, albeit with a small margin, without sacrificing load. We never considered the possibility of an engine cut during the take-off—after all, we were supposed to be immortal.

Venter, Al. Gunship Ace: The Wars of Neall Ellis, Helicopter Pilot and Mercenary

Is this credible?

Mr Joubert looks like he might a coax a boulder into flight by sheer will alone mind you.

Johan 'Juba' Joubert.JPG (34.72 KiB) Viewed 610 times

Artist's impression of Bokkie.JPG (48.6 KiB) Viewed 617 times

Mi-24.JPG (49.59 KiB) Viewed 615 times

I leave it to wiser and far more experienced heads to tell me about techniques that they have used that won't be found in any tyro's flying manual.

Caco

[Boac]

Well, Caco - your next few trips should be interesting for the instructor........

[Cacophonix]

Well, Caco - your next few trips should be interesting for the instructor........

Oh I use this technique all the time now Boac, it is just that my white faced and knuckled instructor doesn't seem to grasp my skill and accomplishment of any technique whatsoever as he shouts "I have control"!


Caco

[CharlieOneSix]

In the Far East when flying the Wessex Mk1 from onshore restricted sites you could find yourself really pushed for power sometimes and unable to establish a hover. A 'running' take off in the Wessex was easy to do. Pull power until you are light on the oleos, stuff the nose down with forward cyclic and rumble along until you unstuck once you had translational lift. There were no performance graphs to tell you if you if you would clear the trees at the other end of the site. Just experience. Great fun!

The Wessex also lent itself to high weight landings in those climes by you arriving at the landing site in a flare, popping the tail wheel on the ground and as you lost translational lift dropping the main wheels to the ground. The Jungly pilots used this technique to great effect - I've failed to find a YouTube clip of a Commando assault demonstration at one of the Air Days back in the 60'/70's - maybe Caco can find an example. It would show the tail wheel being dragged along the ground as I've described. It was the quickest way to get troops out of the aircraft in a hot area, no faffing around establishing a hover!

[G~Man]

When lifting heavy loads on a 100' line sometimes we cannot pick it up. There are 2 ways that help....one is the Wenatchee Snap, where you fly backwards a little, get the line taught and then fly forwards and try to get etl before the load leaves the ground. You need to be very careful, I try not to do this anymore.

The other technique is to reduce RPM's a little as the RPM is set for forward flight vs dead lift, then hover turn so your nose is 90 degrees to the left of the wind, raise collective and allow the nose to spin into the wind as you lift, (by not using left pedal), then nose forward to etl. Not the prettiest but works.

[fareastdriver]

On the Sycamore HAR14 there was a technique known as the jump take off. This was used where there was insufficient power to do a normal take off and with a castering nose wheel a running take of was impractical.

Sitting on the ground the Rrpm was increased to max permissible, about 245 Rrpm. The collective was raised excessively high at the same time opening the throttle wide open. The aircraft would 'jump' into the air and you would be about five feet up. As soon as the aircraft cleared the ground one would ease it forward at the same time playing the Rrpm with lever. With practice transitional lift would come in before the rotor ran out of ideas and then you restored everything and climbed away.

Common practice in the Middle and Far East.

[CharlieOneSix]

..... a technique known as the jump take off......

Caco - in the extremely unlikely event that you and I ever squeezed ourselves into an R22 I think we might need to use this technique!

[Fox3WheresMyBanana]

You can get a Cessna 152 over the Greenland icecap.
You will need to have read 'Fate is the Hunter', and assorted other stories about bombing Germany and flying The Hump, to know how to do it.
I also had the benefit of a TP in a Hawk showing me for 25 minutes one gin clear early morning over Devon. We could see the entire UK and the curvature of the Earth. We were way above the official Service ceiling.
It involves doing hops rather than maintaining a steady climb (since that becomes impossible, typically when the best climb speed and stall speed are 2-3 kts apart). Accelerate to max level speed then smoothly pull up to stall speed and level off. The speed difference is usually very small, maybe 10 knots, and later less. It can take minutes to accelerate those 10 knots, then about 20 seconds to do the hop. The precise technique varies from aircraft to aircraft, and took me about a couple of hours to get it off pat. You can gain about 1,000 feet in an hour, 1,000 ft more than a steady climb would allow.
This is handy when the map has things like "Believed maximum height 10,200 ft" for mountains. There was something about "Here be dragons!" also

I do not know if the same technique would work with rotary...anyone?

[Cacophonix]

..... a technique known as the jump take off......

Caco - in the extremely unlikely event that you and I ever squeezed ourselves into an R22 I think we might need to use this technique!

R44 for us, de minimus, C16! Two fine figures of men that we are! I used to play rugby as a prop and I would have you down as a lock in that pack!

This chap just couldn't seem to get the translational lift going here.



Watching that pilot in the video, I perceive that he is an extremely skilful operator as he seemed to respond perfectly to the "kilogram" too far situation, controlled the helicopter and dropped the load safely. What say the cognoscenti here?

Caco

[G~Man]

Watching that pilot in the video, I perceive that he is an extremely skilful operator as he seemed to respond perfectly to the "kilogram" too far situation, controlled the helicopter and dropped the load safely. What say the cognoscenti here?
Caco

Wenatchee snatch gone wrong---should have kept going forward.

[Cacophonix]

Watching that pilot in the video, I perceive that he is an extremely skilful operator as he seemed to respond perfectly to the "kilogram" too far situation, controlled the helicopter and dropped the load safely. What say the cognoscenti here?
Caco

Wenatchee snatch gone wrong---should have kept going forward.

I guess attempting that snatch running upslope (into wind as required, of course) made his task a little harder. I guess if the wind had been coming from 180 degrees the other way downslope he would have got that translational lift although I ( guess again) the tendency to move out of ground effect, as the ground dropped away, that way, might also be a problem?

Caco