PDA

View Full Version : DC3 nonsense article in Flight International


Centaurus
2nd Aug 2010, 13:13
Flight International 20-26 July page 65 and heading Oshkosh Review.
The FI aviation correspondent gets to fly a C-47 (military DC3) on a couple of circuits. Extract from his report: Quote:

"Once level at 2500 ft amsl and 104 knots I was able to perform some gentle 20 degrees angle of bank turns. Using ailerons to try and turn the aircraft was a lesson in futility. Increasing the aileron deflection only served to generate adverse yaw.

While I had been prepared to co-ordinate the turn with rudder, I quickly learned that to turn the C-47 one only needed rudder, with the ailerons providing style inputs at the best. The lesson learned was I found the C-47 to be a solid predictable aircraft that required the use of ailerons to co-ordinate turns" Unquote.

Surely the journalist jests? "One only needs rudder to turn a DC3" - and "use the ailerons to co-ordinate turns?"

Pprune readers who have flown DC3's must be horrified to read such rubbish.
I was.:ugh:

411A
2nd Aug 2010, 15:49
I quickly learned that to turn the C-47 one only needed rudder,

What utter complete nonsense.:eek:
Using only rudder in the DC-3 can get you into difficulties (rudder lock) that can prove quite unsuccessful, and possibly fatal.

grebllaw123d
2nd Aug 2010, 17:36
Flew this type for several years, although many years ago.
But I am 100% sure, that in order to turn you used ailerons with proper rudder input to counteract adverse yaw. Straight forward! :ok:

AutothrustBlue
2nd Aug 2010, 20:09
Surely the journalist jests? "One only needs rudder to turn a DC3" - and "use the ailerons to co-ordinate turns?"
Nonsense, from the media? No way. Even the flying media is apt to :mad:

con-pilot
2nd Aug 2010, 22:21
As 411A said, getting into a 'rudder lock' situation can ruin your day. I think there was some kind of modification that eliminated that possibility, but then it has been a really long time since I flew a DC-3.

However, I can say I never tried to make a turn in a DC-3 with just the rudder, never saw any reason to actually.

Now you could steer the DC-3 on the runway with just the alerions, now that was fun. Well, as long as you did not have a strong crosswind.

Tenmen
3rd Aug 2010, 02:25
It's been a while since I flew a DC3, but I agree, it's utter rot. And this from a magazine that is written for aviation pro's.

Algy
3rd Aug 2010, 08:08
Here's the article. (http://www.flightglobal.com/articles/2010/07/20/344542/oshkosh-betsys-biscuit-bomber-one-veterans-march-towards-oshkosh.html)
And here's the author (http://www.pprune.org/4198682-post3.html) (posting in another context.)

Air Tourer
3rd Aug 2010, 10:08
You fellers are tough that's for sure. This poor joker on his first go in these old clunkers was sure to get a few strange "feelings". I guess a lot of a/c will mostly yaw using only ailerons, so I don't know what he was up to there. And a lot will kick up a wing and turn using only rudder, but again, why even try it when all turns should use both.

I think the problem is in semantics, but again his fault.
In MY mind, I used to tend to think I was "leading" with rudder input esp in a glider which needs a wack of rudder, and other a/c that have heavy rudders yet light efective ailerons.
This joker might wonder what he was on about if he got used to the DC-3, but hey, two good landings 1st up? that's got to be worth something. :rolleyes:

Mach E Avelli
4th Aug 2010, 03:08
It's dead easy to do a smooth wheeler with no load. C of G is far enough forward to inhibit the worst of its tendency to leap back into the air or ground loop. But fill it to the gunnels with an aft C of G and it's an entirely different beast. Then have a go at 3 pointing it, (which was the way some of us landed it at certain limiting mud or grass strips), and it gets quite interesting if you don't get speed just right and all the drift off.
The author of that article is clearly very experienced and I suspect he did not think too carefully about the way he has written that it mainly turns on rudder with aileron being a mere nicety. Or maybe it just felt that way to him. Ater a long time away from the DC3 I well remember jumping into one and noticing how 'rubbery' and unresponsive the ailerons initially felt. Until I remembered that they need quite large inputs to have any effect.
In the standard DC3 and C47, the rudder lockout thing was never an issue unless asymmetric with it hard against the stops, and even then it was not life-threatening. The so-called 'Super' DC3 may have been different. But it was UGLY, too....

Loose rivets
4th Aug 2010, 03:36
Tell me about this rudder-lock issue, can't say I've ever heard of it. May be just fading memory.:(

The worst swing I ever had from ailerons was on the HP7. Depending on the idividual aircraft, it could yaw in the opposite direction to the aileron input. It was a little like that on the Dak, but not as bad. The flying was really quite basic, even if in slow motion.

However, this thread makes me a bit concerned about the number of times I've had the rudder on full lock, while side-slipping into tight little strips. It behaved very well under those conditions, and came out of the slip with a graceful yet controlled swing.

While on full rudder, the airspeed could be puller right back to a figure that would give astonishingly low ground-speed while in brisk surface winds. It would give the impression of being in an elevator.

Ailerons were indeed very hard work, or seemed so, having come back onto the DC3 from a frisky early phase 1-11.

First time round I was P2 to guys that had flown it 'Over the hump' and in other rather demanding conditions. I recall being somewhat surprised that it could be made to do the things they did with it. Not too many rules about then...well, not ones they cared to abide by.

Old Smokey
4th Aug 2010, 04:25
The journalist's words, as would be expected of most journalists, are pure and utter cr@p!:*

The DC3 was in every respect a 'normal' aircraft to fly, certainly different control feel to other aircraft, but that's normal for comparison between varying types.

Maybe the journo was flying it by auto-pilot, now that's a different matter. Turning a DC3 with it's crude Auto-Pilot was achieved by yawing the aircraft by way of manipulating the Heading control, and it felt terrible. For anything more than a few degrees of turn, it was far better to disconnect the Auto-Pilot, make the turn manually (WITH AILERONS) co-ordinated with appropriate rudder input, and then re-engage the Auto-Pilot.:ok:

Typical journo crud!!!!:mad::mad::mad:

Regards,

Old Smokey

411A
4th Aug 2010, 05:53
The rudder lock issue on the DC-3 happens under very unusual circumstances, usually very aggressive forward slips wherein the rudder is hard over, then cannot be moved central again without using differental engine power.
The primary reason is the very deep rudder hinge line.
This is necessary to use aerodynamic assistance for the rudder to counter high pedal forces that would otherwise be necessary.
A demonstration of this was (at one time) required for the type rating, normally done at a reasonable altitude...at least 5000 feet.

christn
4th Aug 2010, 11:33
I hope Gerz's flying is better than his spelling and grammar!

MarkerInbound
4th Aug 2010, 13:53
I remember times slipping a Three when all of a sudden you didn't have to push on the rudder anymore, it would stay down but as soon as you took all the aileron out the plane straightened out.

enicalyth
4th Aug 2010, 14:27
I had no more said to KO Sally aka my wife... " I wonder if that's Mike". She didn't take the bet. By the way OS he isn't a journalist no more than he is a test pilot but he'll always get his dollar a day from somewhere and can sure swing the lamp and spin a good yarn. That's what he's paid to do and he's just done it, trousered the dollars and swaggered away laughing at us all. The REAL Percy Prune after whom this inspired site draws its name could go one better. Example: "I came in so low over the North Sea that I had to stand up to see over the waves". Now that's shooting a line.....
Mike? He's just a c-c-c-c-c-c-c-c-c-clot. [apologies to "I'm All Right Jack".]

ABUKABOY
4th Aug 2010, 14:37
Rudder locked hard over and increasing airspeed will quickly lead to the situation where no amount of pedal-pressure can centralise it again, and if carried to the extreme, will probably end up with the rudder detaching, as the airflow impinges on the aerodynamic horn forward of the hinge-line. Those hinges are relatively flimsy.
Answer is, don't lose control of the airspeed with the rudder hard over! Reduce the speed, and pedal-power alone will enable you to centralise the rudder. My training (UK) in the early seventies did not include this demonstration due to the above, and it remained a discussion item, and as we did not operate into limiting strips, side-slipping was forbidden.
As for turning it on rudder alone, poppycock! Put the man back in a Tiger Moth and invite him to fly, keeping the ball centred at all times, and THEN have another go in the DC-3. It will all become crystal clear! It's called properly coordinated flying.

Genghis the Engineer
4th Aug 2010, 14:39
Decent, high quality gouge (http://hdl.handle.net/2060/19930083829).

Pages 16, 56 and 57 seem to about cover it (although a roll rate given in radians per second is less than brilliantly helpful); it seems to match my recollection of being observer for a DC3 flight test assessment in the 1990s at ETPS - conventionally heavy controls, but well co-ordinated.

G

Loose rivets
4th Aug 2010, 15:43
Thanks 411A . . . and Marker, that brings back some memory of the general feel.

The last thing I'd have done with such radical control deflections is to let the airspeed build up, so it sounds as though that's the reasons I only felt the slightest hint of Marker's description.

Crossed up, the aircraft felt as though it was to a large extent resting on its fuselage. Very stable, yet still quite maneuverable - without un-crossing the controls.

"Standing up to see over the waves" made me laugh. Not quite that bad, but trying to make sure that we didn't get salt water spray on the bird was a reality.

Time and time again, carriers were returning from Sumburgh having gone around due to low cloud (the aids were primitive on the old field) I realized that so often the viz below was crystal clear the whole way. Trouble was the cloud base was very low, but if I could see Fair isle Fair Isle Home Page (http://www.fairisle.org.uk/) on the horizon, i.e., at a safe distance, it was more often than not, possible to see clearly for the entire flight to the lead-in lights that curved round the hotel. It was imperative not to allow the aircraft to climb into the stratus, hence the need for the ability to bully it a little should it become necessary. That only came by practice, practice, practice.

I should hasten to add, we flew a lot of empty sectors in those days. After about 400 hours in the left (and 500 in the right) I gradually got more daring with the things I'd try, but one thing left me beaten. Just try getting a DC3 down from say, 9,000' in a hurry. Nothing I could do would make those vast old wings come out of the sky quickly. I imagined being on fire and trying to be on the ground in c 3 mins. Huh! Double that if you were lucky.

Chris Scott
6th Aug 2010, 15:10
Thanks for the link, Ghenghis the Engineer, and the narrative of page 16 completely rubbishes the Flight International correspondent's assertion (as quoted in post #1 by Centaurus) that "increasing the aileron deflection only (serves) to generate adverse yaw."

Am surprised to learn, however, 42 years after a short stint (500 hrs P2), of the issue of rudder lock. I'm sure it was not covered on my course or on the line at Morton's, and for that time we had some of the most experienced C-47/DC3 skippers in Europe, e.g., Jo Rechka and Bill Caldwell.

The same page of the NACA report also confirms that the heaviness of the aileron controls is slightly above normal limits at airspeeds over 140kts (presume that must be in a dive!). Even at approach speeds, it could be quite an effort to pick up a wing-drop on a gusty day. That, and the initial rudder loads in asymmetry (a frequent event...) may be why our petite lady pilot, Yvonne Pope, never sought to get a command on the Gooney Bird.

Chris

A37575
8th Aug 2010, 06:12
Is "rudder lock" another term for "rudder tramping?" We used to experience rudder tramping on Lincolns with two engines out on one side and full rudder needed to keep straight. At the time the cause of rudder tramping was never explained to me and I still don't know. But it was a bit worrying at the time because you didn't know what would come next.

411A
8th Aug 2010, 06:31
Is "rudder lock" another term for "rudder tramping?"
Dunno, maybe...depending on the symtoms.
Rudder lock on the DC-3 was caused by the very deep set rudder hinge line.
Was the Lincoln rudder similar?

NB.
It seems to me that proper rudder use is one of the least understood aspects of flying.
Some pilots don't use enough (in many types of early aircraft, the C-46 is a prime example) and a few use far to much rudder (example, AA587), so, perhaps a reference to DP Davies superb book, will lend some thought to those that have never thought much about 'the rudder'.
IE; it can kill you dead if not used properly.

Mach E Avelli
8th Aug 2010, 08:38
Rudder tramping occurs with full rudder application (as needed when engine fails at low speed) on several types that come to mind - F27 being the most notable. I am unsure what is the cause. Could be due to play in the trim tab circuit, could be prop wash, could be the rudder or trim tab at point of stall. Probably varies with type. Any ideas?
The thought of rudder lockout is a whole lot more scary. Never experienced that one. But then I never attempted to sideslip a DC3 and can't imagine any reason why anyone would. The whole hinge setup at the back end of a DC3 looks too flimsy to be messing with radical moves.