Talk:Dutch roll

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Quote from the article:

This technique is more commonly referred to as a slip. If the airspeed is allowed to decay the aircraft can stall, and the crossed controls can cause it to spin

That's completely untrue. Stalling in a side slip will NOT induce a spin.

Also, the speed is irrelevant in stalling a side slip. If you pull the stick back to the point of stall with crossed controls, you will fall out of the sky like a brick and may even notice an increase in airspeed.

>>>>>>>>>> I beg to differ. I don't know where you got your information, but I spent three years in an aero engineering program, I've been a private pilot for more than 10 years, and I'm building an Experimental aircraft.

Stalling with crossed controls is *precisely* how you enter a spin. Not all aircraft WILL spin, but the sentence is accurate as it stands - a spin CAN result from a stall with crossed controls.

A sideslip will normally result in an increase in descent rate without an increase in airspeed. Pilots of aircraft without flaps (such as the one I'm building) commony use sideslip to control rate of decent on final approach. For a wheels-eye view of what that looks like, see this video clip: Video of a slip from camera mounted on landing gear

Brendano 13:40, 29 August 2005 (UTC)

______________ That's fine - You can beg to differ if you want. I got my "information" from years of competing in aerobatics. Thanks for the video - I fly a Pitts - I see that every time I land.

First you say that crossed controls is "precisely" how you enter a spin - And then the very next sentence you say that this will not put all aircraft into a spin.. So which is it? If you think crossed controls is "precisely" how you get into a spin, we'd better let CIVA, Haute Voltige and all aerobatic training organisations know that they've been doing "precisely" the wrong thing all these years - That is stick full back an full rudder... Thanks for clarifying this for us.

I suspect you were thinking of accelerated spins - where the controls are crossed - But this is done AFTER the spin has been initiated. If you pull full backstick with crossed controls (accelerated stall in a sideslip) - it won't enter a spin. I tried this several times out of curiosity before I posted. See this video of an accelerated spin: http://www.airborne-aviation.com.au/gallery/videos/pitts050813-spins.wmv The controls aren't crossed until one full rotation has been avhieved - For this reason.

Also - Being a Pitts pilot I obviously know that a controlled sideslip on finals will increase descent rate without increasing airspeed - Read what I wrote again - if you induce and sustain a stall in a sideslip, airspeed MAY (and most likely will) increase as you plunge to Earth.

It's one of those aviation myths - Like falling out of downwind turns and bernoulli being the primary generator of lift... I know we'll just have to agree to disagree on this.

Contents 1 Technical 2 Aerobatics doesn't seem to pay off 3 Etymology? 4 WikiProject class rating 5 Illustrating the out-of-phase modes

[edit] Technical

I added the "too technical" comment here and at phugoid because I had no idea what a "rudder singlet or doublet" is. Most of the article is a little beyond the average reader, I think, but it's a fairly esoteric topic. Still, it could be made more accessible.--andersonpd 22:58, 26 October 2005 (UTC)

I added a common language first sentence and some clarifying details on singlets & doublets. I'm removing the technical tag. Knotnic 22:26, 21 December 2005 (UTC)

Believe me, this is as non-technical a description as is possible. I would have started with the factorisation of the lateral stability quartic. You know, kept things nice and simple by just considering stick-fixed stability. Gordon Vigurs 08:13, 30 May 2006 (UTC)

I also find it difficult to understand it. I'm a pilot and a student aerospace engineer, yet, I barely understand what this article is trying to explain here. Perhaps graphical illustration and more structual explanation would help. En51cm 05:35, 23 March 2007 (UTC)

[edit] Aerobatics doesn't seem to pay off

Sorry to tell you Brendano but you are incorrect. I have been a flight instructor for some time and have flown many different airplanes. If you recall from AC 61-67 a spin is "an aggravated stall resulting in autorotation." You are correct that a stall while in a sideslip will greatly increase rate of descent. Also, in MOST airplanes a slip will not result in a spin if actions are taken within a reasonable amount of time to counteract the situation. The determining factor is the stability characteristics, control authority, and weight and balance. I have put airplanes into a spin both through slips, and skids. It sounds like you are speaking from experience in a Pitts which I have not had the pleasure to fly, but your dear friend above has hands down won the argument.

[edit] Etymology?

There are currently two contradictory Etymologies for Dutch Roll in the article.

One states "The name comes from the movement that (Dutch) skaters make when skating on ice." and the other states "The name comes from the original design of Dutch ships that had very rounded bottoms for a lower draft". They cannot both be correct.

Could someone please verify which is correct. Ideally, quoting a verifiable source. eg. My first piloting book ISBN 747-360-90-0 states on page 6 "Flying through low cloud in mountainous regions is asking for trouble...." GordonTG 23:30, 5 November 2007 (UTC)

I'd also like to propose a third: the roll aspect is similar to the cinemaic term Dutch Angle. http://en.wikipedia.org/wiki/Dutch_angle Frankly, all of these seem like folk etymoligies with zero real evidence. Paulc206 (talk) 02:33, 9 February 2008 (UTC)

[edit] WikiProject class rating

This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 09:48, 10 November 2007 (UTC)

[edit] Illustrating the out-of-phase modes

It seems to me that Image:DutchRoll AnimGIF 01.gif fails to illustrate that the roll and yaw oscillations are out of phase. Perhaps it is instead the derivative of yaw and the roll which are out of phase; I'm not sure what "lags significantly behind" means. Is there a correction to be made here? --Tardis (talk) 16:25, 10 June 2008 (UTC)