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Can you enter a spin from a slip?

gasman

Well Known Member
Friend
I bring up this topic only because there are many pilots that are shy about slipping to a landing due to the cross control and so close to the ground that they would not be able to recover.

The answer to this question will surprise those that fear the slip. But prove it to yourself at altitude.

The up front answer is ........ NO..... But there is a far more detailed answer than that. Let's let the group explain.


This is a broad statement. And there must be some aircraft out there that you can't (or not allowed to) slip. I am talking about the planes that WE fly and learned with.

EDIT 5/4/2013..... If you just joined this thread, please go to
http://www.vansairforce.com/community/showpost.php?p=768005&postcount=46 and read it first. You are looking for this post.... skylor .... Enough hangar flying.
Then explore the rest of the comments posted here.
 
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I just recently learned more of the spin cause and that it is not really a cross control problem that we all learned.
So to answer the question, no not really.
 
I haven't tried it in my -4 yet, but my C-150 with the controls crossed to the stops would stall straight ahead. It actually surprised me.
 
From the best of my knowledge an airplane MUST be stalled to spin, slip all day long, as long as you don't stall, you will not spin.
 
The answer is YES. The question mixes the apples and oranges a bit.
A spin is the result of stalling and being in uncoordinated flight.

You can stall a wing in any attitude and at any airspeed etc?.stalling is a function exceeding the critical angle of attack (we train them in a way that lends itself to thinking that it is strictly airspeed related/at 1G/straight ahead). Stall an airplane straight ahead and apply full rudder (uncoordinated flight) and the airplane will do a snap roll which is just a spin on the horizontal plane instead of the vertical plane.

So back to the slip: if you don?t exceed the critical angle of attack / maintain proper airspeed you are fine. Often the airspeed indicator is not accurate during the slip due to the pitot tube not being perpendicular to the wind and the natural tendency for most people is to allow the nose to rise when entering the slip.

I have no problem slipping til just before touchdown, a J3 is great for that .
 
Yes

Of course you can - a spin is the result of continued cross-controlled flight after a stall - whether it be straightr and level of with unbalanced control inputs. If you want to do a serious skid, be aware of your aorspeed and hopefully aware of the airspeed where the wing departed controlled flight.
 
Slipping

I fly with the air cadet program where we fly gliders and Bellanca Scouts as tow aircraft.

We complete approximately 8-10 take offs and landings per hour and aggressive slipping is quite common on final.

At no time have I been anywhere near a stall in the cross control configuration while aggressively slipping. An approach speed of 70mph in an aggressive slip is no problem at all.

I'll be heading out this weekend to fly the tow and I'll hook up the camera to capture some aggressive slipping and post it to youtube for those interested.

Cheers,


DP
 
Slips are a great skill to have in the toolbox. They are good for helping loose energy FAST. They can help make up for inop flaps or spoilers.

Just remember that when you are in a full slip, the ASI will probably read zero - keep the nose low to make sure you have enough speed, or eventually you will stall and be busy recovering :)

TODR
 
Nobody's really addressing the OP's question head on. Yes, you can enter a spin from a slip...one done from high speed which effectively snap rolls the airplane, then decays into a spin. But that's not really what we're talking about when we talk about stalling from a slip. What's the purpose of slipping? Either to lose altitude on final, or for x-wind correction. Both are done on FINAL at normal approach speeds. I think we need to keep this discussion in that context. Yes, you could probably stall/spin certain airplanes from a certain speed on final if you really yank the stick back and kick rudder. That's not a very realistic scenario.

The more realistic scenario is that you're slipping on final, and progressively get too slow, maybe accidentally. In this sense, I've never flown an airplane that will spin out of a slip if you progressively pull the stick back, trying to stall the airplane. In all the airplanes I've tried this in, including RVs, you can have full rudder, elevator, and aileron deflection, and the airplane will just sort of bobble along, not really even stalling properly...much less spinning. However, if you neutralize the aileron without removing the rudder and elevator, you're now skidding and can easily spin. In the approach to a stall from a full-deflection slip, most airplanes will NOT spin.
 
I know the ASI will be inaccurate in a slip but

how about the AOA--is it as inaccurate as the ASI, or can it be used to prevent a stall/spin in an overly aggressive slip?
 
AOA value aside, anyone concerned about the possibility of stall/spinning from a slip by getting too slow (not yanking a snap roll) should go out and try it. If you're not comfortable trying, find someone who is. If you haven't tried it, I think you'll be surprised at the non-event you witness.
 
No yaw, no stall, no spin. Need both to spin.

I've done stalls in a slip. Very benign.

Stalls in a skid? No thanks :)
 
Yes, you can enter a spin from a slip. But if you do, your wings will roll past level as they bank to the other direction for the spin. If you stall while in a skid, and are banked, you won't roll past level, but rather will spin in the direction you've banked.

Thus, you have a little more time to give some opposite rudder and lower the nose if you start to stall while in a slip, than if you start to stall while in a skid.

I consider forward slips to be a graceful, elegant way to lose altitude/steepen one's descent angle without picking up speed. If your plane has no flaps, slips can be even more useful. Follow your POH... some aircraft have restrictions.

Side slips are required to do a crosswind landing without imposing side loads on the gear.

In short, slips are safer than skids when it comes to avoiding spins. No need to be afraid of slips. Practice at altitude so you get a good feel for that part of the flight envelope.
 
My understanding is that Luddite has it correct.
A stall in a slip is just a stall as both wings will stall at the same time.
A stall in a skid stalls one wing first, drops one wings and develops into a spin.
So I guess you can spin a plane from a slip but then it is not a slip if you kick the opposite rudder.

Its kinda the chicken or the egg first thing.
A spin doesn't develop because of uncoordinated controls, it develops because a down aileron causes a greater overall wing camber and a wing with greater camber will stall at a lower AOA than a low camber wing (aileron up). This causes the aileron down wing to stall first and drop.
Aileron down is usually caused by uncoordinated controls.
At least that is my understanding.
 
SideSlipping

I was taught to fly by the Air Cadets here in Canada. Received my Glider's Licence in 1977 and learned how to sideslip that year. Went on to receive my Pilots Licence with the Air Cadets on Grumman Cheetahs the following year. Again learned how to sideslip that year. Have been sideslipping ever since and do it on my RV-4 when I need to.

I'm still here and have never had a problem with it. Works good for me!
 
The Lancair IV guys might have a different opinion...(g)

I've never seen a Lancair do a slip to land. Do they go around trying to spin IV's from slips? There are all kinds of airplanes out there with all kinds of characterstics. Nobody's saying anything applies to all airplanes. In all the rag and tube tailwheel airplanes, RVs, and aerobatic airplanes I've flown, I've never been able to produce a spin from a power-off slip to land type of setup. But I would imagine there are some that will. It's a little like saying airplanes are recoverable from spins. Yes - most are, some may not be.
 
Addressing the original question...

No, you can't generally spin (or stall) from a slip.

Why? Because the turbulent airflow over the fuselage blanks the "downwind" side of the tailplane when you're in a slip. Without smooth airflow over the tailplane, most aircraft will lack sufficient elevator authority to raise the main wing's angle of attack to the critical angle.

In the Australian glider syllabus, demonstration of the aircraft's lack of desire to stall or spin in a full slip with full back-stick is one of the take-aways from the sideslip lesson plan. I've done thousands of the things over the years while instructing in a variety of two seat types and a wide range of weight and balance configurations, never stalled off any of them.

Gotta confess that I haven't tried it in the RV, but the -6's elevator doesn't look grotesquely large to me, so unless it's some kind of aerodynamic mutant I'm pretty sure it won't stall in a slip either.

- mark
 
Spins happen from yaw, not aileron inputs

My understanding is that Luddite has it correct.
A stall in a slip is just a stall as both wings will stall at the same time.
A stall in a skid stalls one wing first, drops one wings and develops into a spin.
So I guess you can spin a plane from a slip but then it is not a slip if you kick the opposite rudder.

Its kinda the chicken or the egg first thing.
A spin doesn't develop because of uncoordinated controls, it develops because a down aileron causes a greater overall wing camber and a wing with greater camber will stall at a lower AOA than a low camber wing (aileron up). This causes the aileron down wing to stall first and drop.
Aileron down is usually caused by uncoordinated controls.
At least that is my understanding.

It's quite possible, though more difficult to make the plane spin in a slip than a skid. We used to call it an"over the top spin entry", as someone else noted the plane will roll back through level flight as it enters the spin. In my early training I did this in a C-150, it can be done. Picture full right rudder with the left wing lowered in an aggresive slip. If you manage to stall the aircraft in this attitude (it's not easy, in most aircraft you need to be pretty aggressive with the back stick) the right wing will stall first and drop, bringing the left wing up. If you hold the control inputs, the left wing wil continue through level flight, and the aircraft will enter a spin to the right. As others have mentioned, entering a spin from a skid is much easier.

Aileron has very little, if anything to do with spin entries, it's all about exceeding the critical angle of attack with yaw. Most competition spins are done from level flight, with the ailerons held completely neutral. Trying to stop the rotation of a spin, or even bring up a dropping wing with aileron in a stall will not work if the airplane is yawing, though most who have not had spin training or practiced a falling leaf maneuver will always try to do just that. Once in a spin, if you use opposite aileron, you will most likely (depending on the aircraft) flatten the spin. Out spin aileron, full forward stick (this will accellerate the spin) added after the spin has developed, and adding full power (this brings the nose up to nearly level flight attitude) will give you a very flat spin in a Pitts that will rotate so fast, when you recover your head will still do one or two turns all by itself!

Disclaimer: all aircraft can have different responses, and that changes with load and atmospheric conditions. Get to know how your airplane responds in these situations, with a trained and experienced instructor, and not only will your confidence level skyrocket, you will be a better and safer pilot for your loved ones and friends who fly with you!
 
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NOT...
All you have to do is stall with one wing more stalled than the other.
It's that simple...:eek:

Not that simple. Most of the time, stalling with unequal AoA between the two wings will NOT produce a spin. A wing might drop, but a simple wing drop during a stall does not necessarily mean there is ENOUGH lift differential (and yawing force) to produce a spin. Spiral maybe. Many don't understand that a wing drop is not necessarily a spin entry because a typical student pilot training flight does not allow the stall to progress to the point of seeing what actually develops. Students are taught to recover at the first indication of the stall, so many think they're a gnats *** away from a spin if the wing drops a little during normal power on and off stall practice.

Most pilots (who are inexperienced with spins) don't understand how much effort it takes to enter and sustain an actual spin. In most airplanes, it takes more than just stalling with the ball off center...or even well off center. Most airplanes must be forced into a spin with full rudder AND full elevator deflection. Any less than this and most airplanes are reluctant to spin. You can't simply watch the wing snap over or under, immediately recover, and proclaim that an incipient spin entry. Wait and see what happens. Unless the rudder is on the floor and the stick in your gut, I think you'll find that any (spiral) rotation that develops can be recovered simply by breaking the stall by moving the stick forward and using the ailerons right away. Try that during a real spin and the ride will suddenly get even more fun.
 
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The slip is so good for altitude control on final approach

For 15 years I flew our beloved red, silver and black Piper Archer II (N8304L) to work IFR or VFR (VFR prefered for time & distance) and every day that it was VFR, before the tower opened, I would cross mid field roll into a hard right turn and slip all the way around to just before touch down on runway 19 at El Monte (EMT) without crossing the street at the north end of the airport. One morning there was a cross wind from the west that caused me to overshoot the runway centerline to the east. Banked over that hard I used the stabilator to "bring it back." It worked fine as it had for hundreds of times in the past but perhaps with not as much aggression as I applied that morning. As the plane was coming around the last part of the eastward excursion there was an attention getting burble/shudder/vibration and the plane flew through it fine but I knew bad stuff nearly happened and I became a little more cautious after that.

Bob Axsom
 
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Most pilots (who are inexperienced with spins) don't understand how much effort it takes to enter and sustain an actual spin. In most airplanes, it takes more than just stalling with the ball off center...or even well off center. Most airplanes must be forced into a spin with full rudder AND full elevator deflection.

I recently conducted spin training, and this was one of the biggest benefits of the training - demystifying the belief that a spin is like a snake hiding in the grass waiting to strike. It really took full control input (and held) to enter. Every plane is different; this initial training was not in my plane. Next session will be in the RV. Very glad I did the training.
 
Slip to upset?

Consider left turn to final; hard right rudder, hard left stick, nose up - what could happen?

On a swept wing aircraft the right wing will be blanked out by the fuselage, and with the greater wind across the left wing cause a hard right roll and put one on one's back.

The ? above: can such happen with a straight wing? Not to be tried in the traffic pattern, eh?
 
AT LEAST ONE EXCEPTION

Good morning/evening all,

This is a good discussion, but, as usual in aviation, exceptions may lurk just around the corner.

Once upon a time I was flying a Macchi MB326H jet on a post deeper level maintenance flight. The Macchi was a joy to fly - benign - usually it would only spin with pro-spin controls, nose low, and would recover quickly by centreing the controls. Although the standard spin recovery was: throttle closed; full opposite rudder; stick centrally forward.

On this flight, as usual, I conducted a precautionary, 1G, balanced flight stall before I planned to check the spin characteristics of this particular jet. At the stall, the aircraft rapidly auto-rotated and entered a relatively flat spin although quickly I had centralised the controls. Eventually, I recovered from the spin using full forward stick, full opposite rudder, and either in-spin or out-spin aileron - after three attempts (using standard spin recovery) had made no difference to the spin. I did try both in-spin and out-spin aileron, but could neither remember then, nor now, which helped - I was surprised, and pre-occupied with altitude remaining.

Apparently, there was a slight mis-rigging of the flaps, which was missed by an experienced maintenance crew, the quality control inspectors, and me.

So please remain wary, and try any new adventure at a safe altitude. You never know when you might use all the altitude you have.
 
how about the AOA--is it as inaccurate as the ASI, or can it be used to prevent a stall/spin in an overly aggressive slip?
What's an "overly aggressive slip"? I've often slipped with full rudder and as much stick as necessary to maintain a forward slip.... never thought of it as overly aggressive, just very effective!

My guess is that your AOA probe will also be inop during a full slip.

TODR
 
I used to slip my RV 8 to lose altitude in a hurry if I was high on final. Worked great. Sold that RV 8 and now have another. Guess after reading all this, I'll "slip test" the plane at 7000' the first few times just to make sure. Incidentally somebody was talking about not slipping a swept wing? You can slip an A 300 airbus---works just like a RV 8. But I've heard don't try it in a T tail airliner. Guess, as many have said, it all depends on which type of airplane.
 
Mr. Luddite needs a ride in an SGS 2-32

Mr N355DW is correct. You can spin over the top from a spin if you have enough rudder power to generate enough yaw-rate, and enough wing-span to create a significant velocity difference, and AOA difference between the wings. There is no better aircraft in the world for demonstrating this than a Schweizer 2-32 glider. They spin over the top beautifully.

Also, most of the commentors here are ignoring the effect of dihedral. Ailerons are not the only way of making the AOA different on the two wings.

Think about this for a minute: In straight-ahead flight, How does the airplane know the difference between a skid and a slip? There is none. The distinction only makes sense when you are turning. In straight-ahead flight, if you cross control, using wing bank to cancel the side force from yaw, you have a significant difference in angle of attack between the wings because of dihedral. Now, if you have enough elevator power to stall, one wing will stall first. And it will drop.

Disputing what Mr. Luddite said about wing drops, the dropping wing sees a BIG increase in AOA instantly. Depending on a lot of details (airfoil characteristics, wing twist, wing taper, tip shape) that dropped wing may just turn you into a spiral dive, or it may snap you into a spin. It depends a lot on the variables I mentioned above.

But certainly, get in a hard slip, and bleed the speed off agressively, and it will spin in the direction away from the slip (over the top).

Not that simple. Most of the time, stalling with unequal AoA between the two wings will NOT produce a spin. A wing might drop, but a simple wing drop during a stall does not necessarily mean there is ENOUGH lift differential (and yawing force) to produce a spin. Spiral maybe. Many don't understand that a wing drop is not necessarily a spin entry because a typical student pilot training flight does not allow the stall to progress to the point of seeing what actually develops. Students are taught to recover at the first indication of the stall, so many think they're a gnats *** away from a spin if the wing drops a little during normal power on and off stall practice.

Most pilots (who are inexperienced with spins) don't understand how much effort it takes to enter and sustain an actual spin. In most airplanes, it takes more than just stalling with the ball off center...or even well off center. Most airplanes must be forced into a spin with full rudder AND full elevator deflection. Any less than this and most airplanes are reluctant to spin. You can't simply watch the wing snap over or under, immediately recover, and proclaim that an incipient spin entry. Wait and see what happens. Unless the rudder is on the floor and the stick in your gut, I think you'll find that any (spiral) rotation that develops can be recovered simply by breaking the stall by moving the stick forward and using the ailerons right away. Try that during a real spin and the ride will suddenly get even more fun.
 
Keep the info flowing!

Great discussion fellas! As a low time guy, I am learning a lot from all of your comments. Good stuff! Keep the comments coming!
 
Turn Smart

I feel this video is appropriate to this discussion, although it is based around Ag Flying and Ag Aircraft, it still applies to any other plane.

If you have a spare 15 minutes, please watch it. If you don't have 15 minutes, make room for it. It is well worth the time. :)

http://youtu.be/xwrfEsCiltc

- Iggy.
 
Very good

I feel this video is appropriate to this discussion, although it is based around Ag Flying and Ag Aircraft, it still applies to any other plane.

If you have a spare 15 minutes, please watch it. If you don't have 15 minutes, make room for it. It is well worth the time. :)

http://youtu.be/xwrfEsCiltc

- Iggy.

I know Wayne and this is as good a demonstration, in flight, as you can get.

So yes, a cross-controlled condition can make you spin.

Thanks for posting,

Best,
 
Disputing what Mr. Luddite said about wing drops, the dropping wing sees a BIG increase in AOA instantly. Depending on a lot of details (airfoil characteristics, wing twist, wing taper, tip shape) that dropped wing may just turn you into a spiral dive, or it may snap you into a spin. It depends a lot on the variables I mentioned above.

I'm not sure which airplanes you're referring to, but I'm talking about airplanes that are commonly spun, and for which their spin characteristics are well-known. I'm talking Cessna trainers, Cubs, Champs, Citabrias, Decathlons, RVs, Pitts, Extras, etc. The reality is that unless you have more than one control fully deflected (and held), that even a sharp wing drop is very unlikely to develop into an actual spin. I've done plenty of this stuff, and that is based on my experience, not theory. Maybe it's easier to get a wing drop spin in Lancair IV's, P-51's, T-6's, or Barons. I don't know. But I don't think there's much experience and knowledge base out there regarding spinning the more exotic types...especially the ones that are not approved for spins. My point was simply that in the commonly spun airplanes, you can drop a wing all you want during stall practice, but unless you have multiple hard control deflections continuously held, it's not likely a spin. None of what any of us say is any substitute for obtaining training and actually going out and trying it.

But certainly, get in a hard slip, and bleed the speed off agressively, and it will spin in the direction away from the slip (over the top).

Nobody has disagreed that you can snap roll an airplane out of a slip with a hard yank of the elevator. Again, in the commonly spun types, approach the "stall" slowly, and you're likely going to be bobbing along with full elevator, rudder, and aileron...without spinning.
 
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No yaw, no stall, no spin. Need both to spin.

I've done stalls in a slip. Very benign.

Stalls in a skid? No thanks :)

you are 110% correct and it demonstrates the lack of spin understanding. GUYS....YAW CONTROLS EVERYTHING.... I suggest each one of you to take Bill Finnegan Spin and Emergency Recovery Training. A must have for all....I spin almost every time I go flying and have used Bill for the last 6 years as part of my training. Just ask Smokie of Team Aero Dynamix (Team RV) what he thinks about the training he got from Bill 3 years ago.......you will be surprised!
 
Great discussion fellas! As a low time guy, I am learning a lot from all of your comments. Good stuff! Keep the comments coming!

Please BE CAREFUL...as usual, Spins are highly misunderstood and most of the answers here are just plain incorrect. I fly 2 to 3 times a week inside my Aerobatic Practice Area over KLKR and every single flight involves a different spin from upright to inverted in both directions, flat and accelerated...

Not telling or trying to convince you or anyone about Spins....just suggesting to get proper Spin Training from a well known training service providers with (Aerobatic) ACFI's not just CFI's . in my previous post I recommended Bill Finnegan who is not only a Master ACFI's but also a EAA IAC Hall of Famer. (NONE BETTER FOR SPIN TRAINIG IMHO)
 
Spin training in CA

Warren.....got your email...never got it here as a private message or as a post response....TUTIMA Air or Rich Stowell will be my first two choices...they are well known, they are IAC competitors, do this continuously in good proven aircraft....Both equally good!

Tutima Academy of Aviation Safety - Sean D. Tucker KIC - King City, CA
Chelsea Engberg. Phone: 657-888-4621Fax: 831 385-6582Email: [email protected]eb: www.TutimaAcademy.com
Aircraft:
Extra 300L, Pitts S-2C, Pitts S-2B
Courses:
Tailwheel endorsement, Stall/spin recovery, Unusual attitude/upset training, Recreational aerobatics, Competition aerobatics, Pitts checkout
World class instruction staff/equipment. All instructors are SAC card holders / airshow pilots. Proven competition success. Formation and formation aerobatic training also available.

Rich Stowell Consulting SZP - Santa Paula, CA
Rich Stowell. Phone: 805-218-0161Email: [email protected]eb: www.richstowell.com
Aircraft:
Citabria, Decathlon, Pitts S-2B, Owner-supplied aircraft
Courses:
Tailwheel endorsement, Stall/spin recovery, Unusual attitude/upset training, Recreational aerobatics, Competition aerobatics, Pitts checkout, RV aerobatics Winter location, generally October through May in California
Instructors:
Rich StowellMCFI-A
 
Responses

I don't know why I am not getting your PM's or your post responses...

Don

here is Bill's information.

Dent-Air, Ltd. ANP - Annapolis, MD
Bill Finagin. Phone: 410-353-2622Email: [email protected]
Aircraft: Pitts S-2C
Courses:
Tailwheel endorsement, Stall/spin recovery, Unusual attitude/upset training, Recreational aerobatics, Competition aerobatics, Pitts checkout
Customer Designed Training.

Instructors:
Bill FinaginMCFI-A


Here is a list of all schools "listed" in IAC page.
http://www.iacusn.org/schools/index.php#state_AL_
...notice I say "Listed" not "Sponsored" In you the ATL area I see 3 CFI;s (never heard of them) I will stick to MCFI-A when choosing your spin training....

Close to you I'll recommend

Greg Koontz Aerobatics at Sky Country Lodge AL60 - Ashville, AL
Greg Koontz. Phone: 205-616-8176Fax: 205-594-4207Email: [email protected]eb: www.gkairshows.com
Aircraft:
New Super Decathlon, Clipped-Wing Cub, J-3 Cub, Customers Aircraft (We have experience in most types)
Courses:
Tailwheel endorsement, Stall/spin recovery, Unusual attitude/upset training, Recreational aerobatics, Competition aerobatics, RV aerobatics
: Bed & Breakfast Accomodations on our remote private airstrip. Primary & Sportsman Compitition. CFI Spin Certification. Airshow Waivers. Group Clinics at your site. BEGINNERS ARE OUR SPECIALTY. Teaching acro since 1974.
Instructors:
Greg KoontzMCFI-A, A.C.E.
 
... Again, in the commonly spun types, approach the "stall" slowly, and you're likely going to be bobbing along with full elevator, rudder, and aileron...without spinning.
Then ... Why are they soooo many spin accidents in these "commonly spun types" it they are soooo hard to spin?
 
Then ... Why are they soooo many spin accidents in these "commonly spun types" it they are soooo hard to spin?

I have not researched the NTSB data, but I believe they would be stall, not spin - if by 'soooo many' you're refering to pattern - departure / base to final - incidents. The above video is really good - airspeed is, in fact, life (as quoted). Don't stall and you don't spin.
 
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Then ... Why are they soooo many spin accidents in these "commonly spun types" it they are soooo hard to spin?

It's easier to understand when you quote the entire statement.......

"Nobody has disagreed that you can snap roll an airplane out of a slip with a hard yank of the elevator. Again, in the commonly spun types, approach the "stall" slowly, and you're likely going to be bobbing along with full elevator, rudder, and aileron...without spinning."

He was talking from a slip....

Most accidents that happen in the pattern, base to final, starts with a SKID to a stall.

It is the SKID that kills. The slip to landing gives you more time to react to a stalled wing than a level wing approach.

.......As I entered the pattern the other day, an airplane on the ground announced that it was "taking 29er straight out". A plane that was on base, announced that it would "extend it's base" (he was flying a tight pattern) to allow extra time for the plane on the ground.................:eek:
 
After reading all these pages over the last few days I would've thought the easy answer to the original question "can you enter a spin from a slip?" is:

Yes, if you mishandle it.

Sure, you need both a yawing moment and a stall, neither of which are present in a stable sideslip. But if you're putting yourself under pressure and desperately trying to lose altitude on approach by sideslipping, you're already operating at a reduced margin to stall speed and you've already got a bootful of rudder in. Throw in a lapse of concentration at the controls and there's no reason you couldn't provide the necessary ingredients for entering a spin with greater ease than from normal level flight.

This is why sideslipping, while I have no inherent objection to it, should be handled with care.
 
But if you're putting yourself under pressure and desperately trying to lose altitude on approach by sideslipping, you're already operating at a reduced margin to stall speed and you've already got a bootful of rudder in. Throw in a lapse of concentration at the controls and there's no reason you couldn't provide the necessary ingredients for entering a spin with greater ease than from normal level flight.

This is why sideslipping, while I have no inherent objection to it, should be handled with care.
Why does slipping mean you are desperate to loose altitude? Saying that slips mean you are desperate is like saying flying IFR means you are desperate to get on the ground (Ok, there may be some truth to that, but ....)

Slips can and often are used in normal controlled approaches, and IMHO are really basic airmanship. I can't imagine passing a student who couldn't demonstrate a normal no-flap or (apologies for the non-RV content) no-spoiler approach by using a slip.

TODR
 
It doesn't necessarily. That's why I said "if". I know not all sideslips are "ah cr*p I need to lose altitude fast", but I've seen it done - more than once!

One of the aircraft I fly is often sideslipped on approach because it's one of a couple of ways you can actually see the runway. I don't particularly like doing it for a couple of different reasons and I'm familiarising myself with an alternate technique.

All I'm saying is that if you mishandle a sideslip, you could be in an easier position for gathering the necessary ingredients to spin than if you were not slipping. That's all. It's just a practical answer to the original question.
 
Although the airplane doesn't know it, there is a difference between a "side slip" and a "forward slip" so let's make sure we are using the right terminology.

The difference between the two lies in your track above the ground.

For making a steeper approach without picking up excessive airspeed, a "forward slip" keeps your track going straight down the runway (assuming no crosswind and you're lined up on final) while the longitudinal axis of the airplane is pointed at an angle from the runway centerline (not parallel to it). The idea is to straighten out the airplane before touchdown.

In a cross-wind situation, the exact same control inputs are used to fly a "side slip" in such a way that the longitudinal axis of the airplane is lined up with and/or parallel to the runway centerline. The wings are banked into the wind and the rudder is used to keep the longitudinal airplane axis parallel to the runway centerline. Aileron is used (with corresponding rudder adjustment) to control the amount of sidewise travel so that it exactly counteracts the crosswind component. You would typically hold this condition through landing, touching down on the upwind main wheel first.

A side slip is necessary when landing in a crosswind to avoid excessive sideways loads on the gear. From the airplane's perspective (not "looking" at the ground track), a side slip is identical to a forward slip. Although some aircraft have limitations pertaining to them, slips are generally safe and effective. But the fact remains you can enter a spin from a slip if you stall, so keep the nose down enough to not let the airspeed get too slow.

The classic base-to-final stall/spin accident is typically due to a skidding stall, not a slipping stall. The pilot may, for example, overshoot the final approach coarse, be afraid to steepen his bank at such a low altitude and airspeed, and kick in more rudder instead, resulting in a skid. If he also manages to stall while skidding, he'll be much worse off than if he were to stall while slipping (also not good, but at least he'll roll through level on the way to the spin, and have a better chance at recovering before impacting the ground).

I second the advice that anyone with any questions or uncertainty whatsoever on slips or spins to go up with a CFI who has recent experience teaching them. You won't regret it. For most airplanes that I've flown there's no reason to be afraid of a properly flown slip. Slips have legitimate applications in flying, and by no means should be considered a poor technique or an indication that the pilot necessarily did poor planning.
 
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. Slips have legitimate applications in flying, and by no means should be considered a poor technique or an indication that the pilot necessarily did poor planning.

As an example, I slip the Bucker on nearly every landing. It allows me much better visibility. I am careful with my airspeed, but I have not noticed any pitot "blanking" and airspeed indication remains stable.
I also have not noticed any pitot blanking in my RV, but I rarely slip it (CS prop is a pretty good brake) unless, as noted previously, for cross wind landings. Unlike my Bucker, the RV6 is very heavy on the rudder for any kind of agressive slip. The Bucker is light and silky smooth. Much better balanced overall than RV's.

You have to be pretty disconnected with the feel of your RV to stall in any configuration in my opinion.
 
Enough Hangar Flying

OK, after "listening" to all of this hangar flying I decided to go up and see how my -8 behaves when stalled in a slip.

For my test configuration I was at 1830 lbs and CG @ 83.8".

I performed a couple of full flap power off stalls while in a hard left slip (right pedal to the firewall and enough left aileron to keep the heading stable).

As the aircraft entered the stall, there was a tendency for the right wing to very gradually fall off, but absolutely no tendency to "snap" into a spin.

Your results may vary!

Skylor
RV-8
 
This is a broad statement. And there must be some aircraft out there that you can't (or not allowed to) slip. I am talking about the planes that WE fly and learned with.

EDIT 5/4/2013..... If you just joined this thread, please go to
http://www.vansairforce.com/community/showpost.php?p=768005&postcount=46 and read it first. You are looking for this post.... skylor .... Enough hangar flying.
Then explore the rest of the comments posted here.

This is the only way that you can be sure of your answer. Every thing else is just hearsay...... Thank You Skylor for stepping up.
 
It's still hearsay when you read it on the Internet

This is the only way that you can be sure of your answer. Every thing else is just hearsay...... Thank You Skylor for stepping up.

The most important part of his post was: your results may vary

Just because he got those results doesn't mean you or I could not get his plane to spin in that situation

The bottom line is:

Don't get your aeronautical knowledge from postings on the Internet.

Especially about the edges of the envelope

Find an experienced instructor, preferably someone with a lot of aerobatic experience

Fly with them in your airplane, explore these areas

Get to know it, at all legal weights and cg ranges, on hot days and cold, humid and dry. Change power settings, flaps, trim

Then you can hanger fly with knowledge and confidence! :)
 
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Especially about the edges of the envelope

Find an experienced instructor, preferably someone with a lot of aerobatic experience

Fly with them in your airplane, explore these areas

Get to know it, at all legal weights and cg ranges, on hot days and cold, humid and dry. Change power settings, flaps, trim

Then you can hanger fly with knowledge and confidence!
:)

Yes, that's called phase 1.

But I expect few have tried a stall from a slip during phase 1 for fear of the lower wing dropping and the taboo of cross control slip confused with an uncoordinated skid. A slip stall is no more dangerous than a straight ahead stall.

Anything you feel uncomfortable with, take a qualified instructor with you.

The purpose of this thread was to get people to think, and go learn more about how to fly and enjoy their RV's.
 
Tried to spin

I slip all the time on final - don't have flaps and I like coming in a bit high. This thread encouraged me to try spinning out of a slip (at altitude) in my Super Decathlon (well under gross, CG near middle of range).

Can't do it in that configuration.

Idle rpm (my normal approach) aggressive slip, pulled the stick straight back to the stops. Lots of burble, kept holding, more burble, finally slid off into a spiral, certainly not a spin (I spin the Decathlon regularly).

Tried again, same result.

My results did not vary in any material way from post #46.
 
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