Flying the DC3 in severe turbulence

[A37575]

During my time flying civilian DC3's in Australia decades ago,it was common practice for pilots would lower the landing gear if they encountered severe turbulence, in order to fly at a reduced speed. Pilots Notes for RAAF Dakotas gave no advice on severe turbulence penetration.

Does anyone know why the landing gear was lowered to help reduced speed when a lower power setting would have achieved the same result? I recall the gear down technique was widely known and practiced but the manufacturer did not mention this technique specifically.

Once in severe turbulence and if the speed got real low, the gear was retracted. Can anyone cast any light on why the gear down was used in turbulence?

[BEagle]

Perhaps the lowered main undercarriage added some pendulous roll stability?

[pulse1]

I have read something about Avro York pilots lowering the u/c and flaps in massive updraughts. This allows them to control the speed without reducing the power too much and over cooling the engines. I think it was Nesbit Duforth(?) who used to write splendid articles in Pilot magazine.

In one of his articles he describes an experience when he was still climbing with full flap, u/c down and the engine power reduced as much as he dared.

[Old-Duffer]

pulse1,

Could this be John Nesbitt-Dufort DSO, a distinguished special duties pilot with 138 Sqn at Tempsford?

Old Duffer

[Wander00]

Wasn't N-D the sqn cdr of 138 at one time. One of the other pilots was (later AVM Sir) Alan Boxer, one of the Trustees at the Yacht Club of which I was Secretary for several years - an outstanding officer and gentleman

[Lord Spandex Masher]

Increasing parasite drag and, as a consequence, total drag has the effect of moving the total drag curve (up and left on the speed/drag graph) to increase speed stability, or maintain speed stability at a lower speed. Useful in turbulence.

That's my guess.

[Shaggy Sheep Driver]

I guess they did it to increase drag so there's less chance of overspeeding the aeroplane in the speed excursions severe turbulence brings (even if you ignore the ups and downs and maintin the correct attitude as you should, there'll be times you won't be able to maintian attitude in very rough air and the speed could go beyond Vne if the aeroplane was left 'clean').

[Cornish Jack]

Pulse1 - sounds like the episode recounted by one of the early post WW2 captains flying York freighters out of Lebanon. Fully loaded he entered the base of an active Cb at 6000' and hit up-draughting of such violence that, even with gear and flaps down and engines at idle, they still went up and were eventually spat out of the side at (IIRC) 26000'!!!:eek::eek: Stay clear of the 'thunder-bumpers'!!

[A37575]

Many safety publications advise lowering the gear for speed control.
. Many thanks for the info Bryan A. While I haven't seen any safety publication articles covering the subject I am sure there are around as you say. The trouble with these you have to be sure they are published facts and not the authors' personal opinions. I have been guilty of the latter on a few occasions :=

[Offchocks]

In my youth I did about 500hrs on DC3s in Europe and can't recall this procedure of lowering the gear. Thirty seven years on my first thoughts would be fine if you have increasing IAS but what if you have rapid reducing IAS, with the gear down you have less excess power to overcome the IAS loss. The DC3s I flew did not have much excess power.
This is all assuming you can read the instruments which is almost impossible in "severe" turbulance.

[James Leite]

This suggested procedure of lowering the gear in severe turbulence just has to be dreamed up nonsense. I flew DC3s for 11 years with two reputable airlines and there was nothing in their operating manuals about this. Why should there be ? Increasing the pendulum affect in turbulence is the last thing any pilot would want.
Also I just happen to have a reprint of the DC3/C47 flight manual issued by the USAF dated 15 March 1963. On page 9-4 of the section dealing with " Flight in Turbulence and Thunderstorms " there is the enlarged word " CAUTION " and following on from this is " Do not lower the flaps or gear since structural damage may occur " Doubt if there is anything more definitive than that.

James.

[pigboat]

If I may expound a little on James' post:

APPROACHING STORM:

1...Disengage the autopilot.
2...Reduce airspeed as required.
3...Mixture controls - AUTO-RICH
4...Propellor Controls - 2350 RPM
5...Pitot heater switch - ON
6...Carburetor heat - As required
7...Throttles - As required
8...Check the power source and gyro-stabilized instrument settings.
9...Safety belts and shoulder harnesses - Tightened
10...Turn off any radio equipment rendered useless by ststic.
11...Turn the cockpit lights full bright to minimize the blinding effect of lightning.

CAUTION:

Do not lower the flaps or gear, since structural damage may occur.

[Offchocks]

Perhaps lowering the gear on DC3s for extreme turbulence was a local procedure in Australia. Speculation I know, but it could have come about because some crews had flown types that recommended it and thought it a good idea.