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Wing spoilers vs. ailerons??P-61 Black Widow had spoilers....

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Old 10-13-2009, 09:12 PM
  #26
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Default RE: Wing spoilers vs. ailerons??P-61 Black Widow had spoilers....

Lots of aircraft have roll spoilers...even Cessna's...look at the CX, CIII-CVI series, even the model 208. Usually they have a combination of roll spoiler and aileron both. Simplicity is probably the reason most airplanes do not have them.

Steve
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Old 10-13-2009, 09:47 PM
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Default RE: Wing spoilers vs. ailerons??P-61 Black Widow had spoilers....

Oops, yep I meant cyclic[:@]

Good guess it was a Bell 47.

Dave H
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Old 10-13-2009, 10:36 PM
  #28
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Default RE: Wing spoilers vs. ailerons??P-61 Black Widow had spoilers....

Quote:
This 'phenomenon' is addressed under 'myths'. Deploy a spoiler and one wing has more lift than the other so the aircraft rolls around it's longitudinal axis (i.e. the wing with more lift goes up), exactly the same as when you use ailerons. Essentially any aircraft that makes several rapid roll inputs will lose performance (in this case 'a bit of altitude' ) all else being equal.
I believe this is manfacurers candy coating. The difference is that with ailerons you have one wing creating more lift and the other creating less lift causing thus not losing any total lift as ailerons are applied. The same control input on a spoiler equiped airplane causes one spoiler to raise on the wing you want to roll to and nothing happens on the other wing. Therefore you are decreasing lift on one wing and it is not replaced by lift on the other causing a net loss of lift.

I'm not sure where you got your data on the MU-2 having a better safety record than other turboprops of its class. I also don't know what makes you think that MU-2 pilots would have less experience than pilots of other simular airplanes either.

Quote:
In any case he MU 2 is certified in exactly the same way as all other aircraft and will therefore perform as intended following an engine failure with whatever amount of reduced thrust and increased drag the aircraft has, providing it is flown correctly (part of this certification procedure requires that an average pilot can achieve the required performance so it shouldn't be any harder to fly than any other plane)
This may have been true origonally, however due to the accident rate of this airplane the pilots are required more training to fly the MU-2 than other simular airplanes.

In fact MU-2 pilots are required by the FAA to receive type specific training (simular to a type rating) that is very unusual for aiplanes weighing less than 12,500 lbs. The FAA also requires this plane to have an operating autopilot to fly single pilot, another oddity. These requirements are due to the airplane being much less forgiving that most other.

Quote:
The primary effect of engine failure is yaw, and therefore the correct control input is rudder not aileron (or roll spoiler). In fact once the correct rudder input has been made most aircraft require very little or no aileron input.
This is a little misleading. When an engine fails you not only get a yawing moment, but you also get a rolling moment. You are absolutely correct that the correct control imput should be rudder in this airplane. In most any other twin engine plane you can step on the rudder and keep it mostly steady and control the roll with ailerons. This is what kills MU-2 pilots and this is why the additional training is required.

This airplane is not as tame as the mfg. would like you to believe. Other aiplanes in its class such as a King Air 90 Cessna Conquest, Piper Cheyenne, etc. will kill you alot less quickly than the Deuce.
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Old 10-13-2009, 10:37 PM
  #29
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Default RE: Wing spoilers vs. ailerons??P-61 Black Widow had spoilers....

Better not try stirring the cyclic on an MBB BO-105 CBS (like the Red Bull acro copter) or it will be doing flips. Its rigid rotor sytem responds like an Indy car. Instantaneously! How do I know? I used to work on various American, French and German built helicoters in the '70s/'80s and got lots of stick time on test hops and ferries. The pilots were always happy to have the mechanic ride along on test flights after maintenance.

Terry in LP
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Old 10-14-2009, 11:23 PM
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Default RE: Wing spoilers vs. ailerons??P-61 Black Widow had spoilers....

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Better not try stirring the cyclic on an MBB BO-105 CBS (like the Red Bull acro copter) or it will be doing flips.
Yep pretty impressive, I have seen some video of some German Army BO 105's flying nap of the earth, and of course the Red Bull helicopter aero's.

I was lucky to get 40 minutes in a British Lynx helicopter, with an American Army pilot as it turned out. Went upside down, but not as aerobatic as the 105.

Quote:
The pilots were always happy to have the mechanic ride along on test flights after maintenance.
Yeah me too Me 'Did you work on this helicopter?.... Are you happy with your work?.... Yes.... Great hop in'.

Mind you the Engineers got me back. Engineer 'If you are so desperate to have this helicopter serviceable by tomorrow how about you do the plug change and the tail rotor change, here's the manual... Are you happy with your work?.... Good now get out of my hair and go do the test flight'. They did keep a very close eye on me though, for some reason engineers get very nervous when pilots have tools in their hands
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Old 10-15-2009, 01:39 AM
  #31
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Default RE: Wing spoilers vs. ailerons??P-61 Black Widow had spoilers....

No spoilers or ailerons but...

The only time I was ever upside down in a helicopter was when one of the best pilots I ever knew did a past vertical wing over/chandelle type maneuver in an an old French Alouette III with me in the left seat. That's what I got for asking an ex Cobra pilot if he had ever been upside down in a helicopter. It's an old tech machine but a very nice smooth, responsive, powerful helicopter. And the in flight view through all that plexiglass is spectacular.

http://www.youtube.com/watch?v=M52Fa...eature=related

Terry in LP
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Old 10-15-2009, 02:21 AM
  #32
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Default RE: Wing spoilers vs. ailerons??P-61 Black Widow had spoilers....

Hi ndb8xfe,

Quote:
ndb8xfe
I believe this is manfacurers candy coating. The difference is that with ailerons you have one wing creating more lift and the other creating less lift causing thus not losing any total lift as ailerons are applied. The same control input on a spoiler equiped airplane causes one spoiler to raise on the wing you want to roll to and nothing happens on the other wing. Therefore you are decreasing lift on one wing and it is not replaced by lift on the other causing a net loss of lift.
Like I said, you have to be cautious of the manufacturers word, but this bit from the web site is from an independant consultant

Quote:
MU-2B Myth-Perceptions
Prepared by
Gregory A. Feith
International Aviation Safety Consultant


Myth: Flight Spoilers “destroy” the lift on the wing:

“Destroy” is not a word in the aerodynamic lexicon and unfortunately it is used most often to create an
emotional response. Flight Spoilers, when deployed only reduce the lift-efficiency of the wing in which
the spoiler is deployed. The deployment of the flight spoiler to intentionally induce a roll (typical of a
turn) is similar to and results in the same effect as raising the trailing edge of an aileron. Flight spoilers
are used as the primary flight control for roll in numerous air transport category airplanes, military
airplanes and some general aviation airplanes.

Myth: Flight Spoilers are not as effective as ailerons at slow speeds, because larger control yoke
movements are required for the MU-2B in turbulence during approaches:

This myth has been disproved in numerous flight tests that compared the roll authority of ailerons and
flight spoilers. Roll rates at cruise speeds for the King Air 200 and the MU-2B-60 were found to be
approximately equal when the flight control was exercised to their respective maximum control position.
At approach airspeeds with full roll control authority exercised, the MU-2B continued to achieve greater
roll rates than the King Air 200. The genesis of this myth likely stems from the fact that flight spoilers
are most effective when they are at their maximum deflection. And though there is a nominal change in
roll rate during the initial application of the flight spoiler, the rate progressively increases as the flight
spoiler is deployed until it achieves its maximum rate at maximum deployment. Conversely, the roll rates
in an airplane equipped with ailerons will be the greatest at the initiation of aileron deflection and
progressively decrease with increased aileron deflection. Therefore, although the pilot may be required to
manipulate the control yoke slightly more (than in an aileron-equipped airplane) to initiate a roll action in
the MU-2B, the roll authority will progressively increase proportionally to the increase in control yoke
displacement in the direction of the desired turn.

Myth: Flight Spoiler deflection causes a loss of altitude due to a lateral rotation about the opposite tip
tank:

The origin of this myth is based on the perception that in the MU-2B, when the flight spoiler is deployed
to induce a roll (typically a turn) the ascending wing (moving upward) does not increase lift in the turn
but rather the descending (downward moving) wing loses lift and the rotation occurs around the outboard
portion of the wing rather than the lateral axis of the airplane. An aileron equipped airplane, by contrast,
increases lift on one wing while decreasing it on the other. Thus, it is mistakenly believed that the aileron
equipped airplane rotates around the lateral axis that runs through the center-of gravity (CG) i.e., through
the middle of the fuselage, and that the MU-2B, which is believed to have only a loss of lift on one wing,
thus the airplane rotates around the opposite wingtip. This premise is fundamentally flawed and not
supported by the basic aerodynamic principles (or the current laws of physics) that state that the lateral
axis of the airplane transits from nose to tail through the middle of the fuselage, and always intersects the
CG.
Quote:
ndb8xfe
I'm not sure where you got your data on the MU-2 having a better safety record than other turboprops of its class. I also don't know what makes you think that MU-2 pilots would have less experience than pilots of other simular airplanes either.
I meant to say that pilots of MU 2 and similar aircraft tend to have less experience, not pilots of MU 2's have less than pilots of similar aircraft. Another cut from the web site, sourced from FAA stats

Quote:
Twelve Year Totals
(1997~12/9/2008)
Accidents Fatal Accidents Fatalities
Cessna 400 Series 255 90 282
King Air 90/100/200/300 169 64 236
Piper PA31-42 Series 159 55 168
Cessna 208 Caravan 128 40 163
Commander 500-600 86 34 92
Swearingen SA-226, 227 60 15 53
Mitsubishi MU2 Series 33 21 38

The single most common factor in recent MU2 accidents has been the absence of formal MU2 training, either that simulator training sponsored by Mitsubishi at SimCom or in-aircraft training provided by Howell Enterprises or Professional Flight Training, in the accident pilot’s operation. This may be in conjunction with such pilot’s operation lacking insurance or the decision by an underwriter insuring a fleet of cargo-only MU2s not to require such training. Joint efforts towards the issuance of the MU-2 Training SFAR in 2008 are meant to address this issue.
-It is also noteworthy that cargo-only operations (including, of course, those with MU2s) are held to a lesser standard of safety-oriented equipment, including not requiring autopilots or ground-proximity warning equipment, by the FAA than are aircraft carrying passengers or a certain number of passengers.
I guess these are raw totals not factored per flight hour or sector, check the web site for further info. You may be able to make more sense of it than me.

Quote:
ndb8xfe
This may have been true origonally, however due to the accident rate of this airplane the pilots are required more training to fly the MU-2 than other simular airplanes.

In fact MU-2 pilots are required by the FAA to receive type specific training (simular to a type rating) that is very unusual for aiplanes weighing less than 12,500 lbs. The FAA also requires this plane to have an operating autopilot to fly single pilot, another oddity. These requirements are due to the airplane being much less forgiving that most other
Or the MU 2 is sufficiently different from similar types that specific training is advisable. I don't fly in the FAA environment so I can't really comment on this aspect. I've never flown any aircraft without a type rating specific to the type.

Quote:
Quote:
The primary effect of engine failure is yaw, and therefore the correct control input is rudder not aileron (or roll spoiler). In fact once the correct rudder input has been made most aircraft require very little or no aileron input.
ndb8xfe

This is a little misleading. When an engine fails you not only get a yawing moment, but you also get a rolling moment. You are absolutely correct that the correct control imput should be rudder in this airplane. In most any other twin engine plane you can step on the rudder and keep it mostly steady and control the roll with ailerons. This is what kills MU-2 pilots and this is why the additional training is required.
Yep there is a rolling moment as well but my point was that, given correct use of the rudder, it is small and manageable with ailerons or roll spoilers. At least that's what Mitsubishi and the FAA say

Quote:
Myth: Flight Spoilers cause loss of lift as compared to ailerons:

Obviously, flight spoiler deployment, similar to raised aileron, does reduce the lift efficiency of the wing
and increase drag proportionally to amount of deployment. However, the drag increase from spoiler
deployment is relatively negligible compared to the drag which results from incorrect rudder inputs
(causing a skidding of the airplane) during an OEI (one engine inoperative) event. This was clearly
captured on video during a demonstration flight (shown during the PROP seminars) that revealed that the
proper and timely application of the rudder during the OEI event improves climb performance
dramatically and causes a marked decrease in the flight spoiler deployment required to maintain attitude.
In fact, nearly all of the climb improvement and drag reduction after an engine failure is realized with the
appropriate rudder input. This is true of any non-centerline thrust, multi-engine airplane, whether it is
equipped with ailerons or flight spoilers
. In the MU-2B, after the appropriate rudder input has been
established and the appropriate aileron trim (used on the MU-2B to reduce the aerodynamic loads on the
flight spoilers that are felt by the pilot in the control yoke) has been applied to relieve the aerodynamic
forces on the flight spoilers during the OEI, an additional, but small improvement in climb performance
will be evident. This is due to the fact that the performance (drag) penalty is negated as compared to an
aileron-equipped airplane
because the flight spoiler is trimmed to a recessed or faired position.
I guess I'm playing devil's advocate here a bit, I have no idea if the MU 2 is a safe plane or not, I've never flown one. Interesting thread though, even though we might be starting to drift a bit. (Yeah right, it's not like I caused the drift by bringing up helicopters)

Cheers,
Dave H

Sorry for the long post
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Old 10-15-2009, 02:44 AM
  #33
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Default RE: Wing spoilers vs. ailerons??P-61 Black Widow had spoilers....

Hey Terry,

Another cool machine, I used to watch one operating in the hills behind our house. It was the version with the exposed tail boom, looked like a Bell 47 on steroids. Nice view is right, it's like sitting on park bench, in a gold fish bowl, with a ladder up yer arrr... I probably shouldn't be using that word here. Nice video.

I used to display the UH 1 for our Airforce, I was authorised to fly wingovers to 120 AOB plus some other manouevres that Mr Bell never intended. Was fun but was mostly about orientating the manoeuvre to make it look like the helicopter was doing something it wasn't. The sad thing was that just flying past making that Iroqouis sound was 80% of the display for the ice cream lickers. They werent impressed with the techy stuff much, but lift a monsoon bucket of the back of a moveing truck (fairly easy) and they go nuts.[&o]

Had a go in a Huey gunship once, even got to fire one of the shooty things, but a Cobra. MMMmmm drool.

Dave H
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Old 10-15-2009, 12:46 PM
  #34
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Default RE: Wing spoilers vs. ailerons??P-61 Black Widow had spoilers....

Quote:
Twelve Year Totals
(1997~12/9/2008)
Accidents Fatal Accidents Fatalities
Cessna 400 Series 255 90 282
King Air 90/100/200/300 169 64 236
Piper PA31-42 Series 159 55 168
Cessna 208 Caravan 128 40 163
Commander 500-600 86 34 92
Swearingen SA-226, 227 60 15 53
Mitsubishi MU2 Series 33 21 38
While these numbers are interesting they do not serve much of a statistical purpose. When comparing accidents of one make/model to another the only way to do it fairly is to do it by hours of operation. While I couldn't find this data for free, i did find several articles that state that the mu-2 accidents per operating hour rate is three to five times other turbo prop aircraft.

Here's an excerpt from Breiling, Inc, a company that specialized in aircraft data statistics:

Quote:
Overall, its five-year accident rate from 2000 to 2004 was 3.17 per 100,000 flight hours, compared to 1.73 accidents per 100,000 flight hours for that time frame among other popular turboprops, according to Robert E. Breiling Associates. During the same five-year period, the Mitsubishi's fatal accident rate was 1.66 per 100,000 flight hours, or more than triple that of popular turboprops, Breiling asserts.
If you are really interested here's a link: [link]http://sleetapawang.spaces.live.com/blog/cns!BD09644C5F6E196D!731.entry[/link]

Having said all that, I think we are getting off topic that this OP was looking for. I am a little passionate about this topic as I know some that have perrished in the MU-2, and while I don't blame the airplane, I think in the same circumstances in anoter airplane the outcome may not have been as bad.




Back to models: what do you think spoilers effects would be on an inverted(or -1g) model? would you get a reversal in roll controll?
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