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Can you enter a spin from a slip?

gasman said:
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.
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Yep, I did lots of spins during phase 1, but a stall from a slip just didn't occur to me to try out at that time and didn't make it into my test plan. No fear here, but the discussion did arouse my curiosity which is why I went out and tried it.

Skylor
 
Ok done both saturday upon my return from competition. All done at altitudeof course.... Was unable to spin the aircraft on a skid or on a slip, hoewever while letting the aircraft stall in the skid or slip I did get a nasty spin on both ocasions while failing to remove yaw. by controling Yaw, no spin was attained in several ocasions...... .. let me know if someone wants to try it....im available to demonstrate....myth,s over...
 
mv031161 said:
...while letting the aircraft stall in the skid or slip I did get a nasty spin on both occasions ...
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Here seems to be the proof that with one wing stalled more than the other, a RV can spin :p Lab results backing up the theory.
 
mv031161 said:
Ok done both saturday upon my return from competition. All done at altitudeof course.... Was unable to spin the aircraft on a skid or on a slip, hoewever while letting the aircraft stall in the skid or slip I did get a nasty spin on both ocasions while failing to remove yaw. by controling Yaw, no spin was attained in several ocasions...... .. let me know if someone wants to try it....im available to demonstrate....myth,s over...
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What is the myth? Had a hard time following the above statements and understanding how you set up the skid/slip/stall/spins. And did you do this in your Giles or RV? I have done everything imagineable in RVs.
 
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I can't spin from a slip

:)I tried to see if my RV-4 would spin from a slip both right and left, and couldn?t do it. As I approached a stall in a slip with maximum rudder input, I wasn?t able to hold heading, and it was just sloppy like others that have tried it in an RV. I even tried it inverted (cross controls inverted slip will use same side aileron input and rudder like both left aileron and left rudder with stick forward), and it wouldn?t spin but had a rather rapid loss of altitude with the nose on the horizon. Mitch, our RVs just don?t have enough rudder like your Giles 202. The youtube post #31 for this thread was the most informative to me.
Bill McLean
RV-4 Slider
Lower Alabama
 
Spin

Bill I realize my Giles is not an RV or Vice versa...still, on any Stall you have to introduce YAW regardless of how big that wind vane in the tail is to have a Spin.

For purposes of this particular exercise, I did a slip and skid and purposely allow the aircraft to stall while keeping the cross controlled attitude. Without removing the Rudder the aircraft stalled in both situations and it went into a spin. (YAW CONTROLS EVERYTHING) ...Same situation but this time removing yaw...the aircraft stalled straight and gently.

NOW...Question: if I let it stall on a slip or a skid, can we still call them a Slip or a Skid....I don't think so.....what do you think?

My answer still the same, you can't spin an aircraft on a skid or slip.
 
Slip with Flaps Down

I slip when necessary on final if I'm too high so I don't increase speed. Issue is the flaps are usually down in prep for landing and I have to watch the speed a bit to insure I don't top 100 mph in the decent which is the safe point for lowering flaps. Can I be putting unintended stress on the flaps and damage them with a sub 100 mph slip on my RV-8A?
 
I've never heard of flap damage in any airplane as a result of slipping in the white arc. I slipped my RV with full flaps on every landing for years.
 
flaps

I always slip my RV8 with full flaps when landing at home. It's required when landing over the trees. No problem at all and I often start the slip just under 100 MPH. I believe the "don't slip with full flaps" started years ago with high winged airplanes. There used to be talk about the slip with full flaps deminishing rudder authority. Don't know for sure.
 
For example, the POH for our club's C-172P says:

Steep slips should be avoided with flap settings greater than 20 degrees due to a slight tendency for the elevator to oscillate under certain combinations of airspeed, sideslip angle, and center of gravity loadings.
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Some folks interpret that as a prohibition of doing slips with full flaps in that airplane. I don't have that interpretation, however, and I have done slips with full flaps in that very plane with no adverse affects, although I'm aware of the caution and remember it while I'm slipping.

I can't speak to RV's, but it sounds like RVs are generally very good (and stable) at slipping with any flap setting. Of course, every RV is a "one-off" and these things should be thoroughly tested during Phase 1. (Some control surface trailing edges are better than others!)
 
DEWATSON said:
I always slip my RV8 with full flaps when landing at home. It's required when landing over the trees. No problem at all and I often start the slip just under 100 MPH. I believe the "don't slip with full flaps" started years ago with high winged airplanes. There used to be talk about the slip with full flaps deminishing rudder authority. Don't know for sure.
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There are no rules. Every airplane is different. Some 172s recommend against slips with full flaps. But that's only one aircraft type, and from what I've read from people who actually do it, it's not a problem for them. For EAB's, the point of Phase I is to test the airpalne in all phases and configurations of flight. Again, you can't generalize. But to me, slipping at 100MPH seems to defeat the purpose of slipping. You'd have a steeper descent angle with full flaps at 1.3Vso without slipping than you would slipping with full flaps at around 100MPH.
 
If I am on a long extended straight in approach (not turning) with a 15kt direct crosswind from the right and I add right rudder/left stick to increase descent rate am I slipping or skiding. Same wind but left rudder/right stick, does the answer change? I understand slips/skid while turning but am unsure when on final with no turn. So my bottom line question to the gurus is:
When on final rudder into the wind or opposite the wind?
 
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bobmarkert said:
If I am on a long extended straight in approach (not turning) with a 15kt direct crosswind from the right and I add right rudder/left stick to increase descent rate am I slipping or skiding. Same wind but left rudder/right stick, does the answer change? I understand slips/skid while turning but am unsure when on final with no turn. So my bottom line question to the gurus is:
When on final rudder into the wind or opposite the wind?
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I'm certainly no guru, but as I understand it both actions you describe would produce a forward slip. The difference is the right stick/left rudder slip should keep you lined up with the runway if that's your intention, whereas the other combination will have you heading for the trees.
 
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Slipping vs skidding

When you "skid" your airplane you add more rudder than is required in the direction of the bank. You are most likely turning in the banked direction in this maneuver, although enough crosswind could keep your track straight. I can't think of a situation where you would deliberately want to do this except to demonstrate how skidding easily leads to the stall/spin.

When you "slip" your airplane you add rudder opposite to the bank. Whether you are turning in this maneuver depends the wind and the amount of aileron relative to rudder.

You are slipping when you are cross controlled. To ensure slipping, put the aileron in first then "Step on the Sky".
 
Well said, SMO. I love the "bank, then step on the sky!"

bobmarkert, you're probably in a slip in the situation you describe, but to be sure, next time you do it, take a quick glance at the ball (inclinometer, slip/skid indicator or turn coordinator, or on the EFIS display). You are slipping if the ball is on the side of the lowered wing (your actual airplane wing, not necessarily the rate-of-turn wing on the symbolic airplane on the turn coordinator, as that will be level if you're not turning). You are skidding if the ball is being "thrown out" toward the raised wing -- or if your wings are level and the ball is being "thrown out" away from the direction of your rudder. "Step on the ball" using rudder (and/or adjust aileron) to fix. On final, you want the ball to either be centered or, if you're intentionally slipping, to have "fallen" in the direction of the lowered airplane wing.

A skid means you don't have enough bank, in the proper direction, to match your yaw (or, put another way, you have too much yaw for your bank). I think of it like taking a corner on a level road in a car, feeling myself "being thrown" to the side (not true -- there is no force pushing me toward the side of the car -- I'm just following Newton's laws, but that's another story), and wishing I had some bank.

Experiment at altitude sometime and observe those instrument indications (inclinometer and rate-of-turn indications). Avoid skids at low altitudes or in the traffic pattern. (Is there really any time that you'd *want* to skid?) Avoid stalls in those situations as well, of course. A spin occurs when one wing is more stalled than the other. From a spin perspective, a slip is safer than a skid because if you manage to enter a spin while slipping you will roll back through wings level along the way, giving you more time to apply anti-spin inputs and recover.
 
rgmwa said:
I'm certainly no guru, but as I understand it both actions you describe would produce a forward slip. The difference is the right stick/left rudder slip should keep you lined up with the runway if that's your intention, whereas the other combination will have you heading for the trees.
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No it won't. Slipping one way or the other doesn't change your flight path, if done properly. It only changes your heading. So if you slip with right rudder in a right x-wind, you'll simply have a large alignment correction to make before touching down...as in you'll have to slip in the opposite direction.
 
This has been a great discussion with lots of good points and interesting thought experiments, but I think that the bottom line for practical purposes remains unchallenged - a skid is way more inherently dangerous than a slip.

Beyond all of the various arguments in this thread regarding the differences between slips vs. skids and the stall/spin potentials, I will add that flight schools like the military teach slips as a good thing, the student being routinely encouraged to fly them. Skidding is always portrayed as a very bad thing. Slipped turn stalls are only lightly discussed ("keep your speed up"), while skidded turn stalls are for instructor demonstration only with the resulting snap roll to an inverted recovery reserved to serve as a startling reminder to the unwary student to avoid this evil departure at any cost.

Having done many skidded turn stalls and knowing how hard they are to make happen, I can't imagine how difficult it would be to induce a slipped turn stall. Possible - yes. Probable - no.

I suggest a great way to remember the difference when cross wind correcting or when purposely slipping is "wing down - top rudder". Same as "step on the sky" but an easier image to conger, for me at least.
 
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luddite42 said:
No it won't. Slipping one way or the other doesn't change your flight path, if done properly. It only changes your heading. So if you slip with right rudder in a right x-wind, you'll simply have a large alignment correction to make before touching down...as in you'll have to slip in the opposite direction.
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Interesting. I had in mind the use of right stick/left rudder to counteract drift in a right crosswind landing. Applying opposite controls, it seems to me, would allow the wind to push you sideways off-line. I can see that in a no-wind situation your heading would simply swing left or right in a slip but your flightpath would stay the same. But if you're trying to land in a right crosswind would you want to slip using left stick/right rudder? What am I missing?
 
landing versus flying

rgmwa said:
Interesting. I had in mind the use of right stick/left rudder to counteract drift in a right crosswind landing.
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Right stick/left rudder is what you would normally do with a right crosswind, just before touching down. The way I fly is to have a crab correct for the drift, and then the slip you describe is what gets the nose pointed straight down the runway. Earlier on the approach you can choose to slip the other direction if you want, and your ground track can be kept the same.

rgmwa said:
But if you're trying to land in a right crosswind would you want to slip using left stick/right rudder? What am I missing?
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Normally you would not but that doesn't mean you can't. You would just have to change the direction of the slip to line the nose up with the runway before you actually touched down.

Your original response might have been clearer if it said "whereas the other combination will have your nose pointed at the trees."

YOU decide your ground track, not the wind. Now, if you want your ground track AND your nose pointing the same direction, you have to do as you say, right stick/left rudder.

Go find a straight road to follow at 1000' AGL. Track it in a crab (coordinated flight), then slip to both the left and right. You can track the road in all 3 conditions, but you would only want to touch down in 1 of the 3.
 
I took the Cobra Ball (RV-4) out tonight solo and thought I?ll give it a try, I started out in a nice slip holding heading with full left rudder, progressively letting the airspeed decay, finally it did not want to hold heading, the low wing was trying to raise, trying to find out what would happen I moved my fat thy out of the way the best I could for a little more aileron deflection, We were sinking fast but it was not stalled yet, decay the speed little by little tell it broke over the top faster than you can snap your fingers, I was not surprised by this, it was telling me it was headed for this, upside down now with full flaps, I pushed and continued the roll and recovered well below max flap speed.

I do lots of spins, stalls and acro, this did not surprise me, I could see where it was headed, recommend if your slipping on final and she tries to lift the low wing, relax the pitch, there was plenty of warning but when it went there was no buffet, it just let go, would it have spun? It doesn?t mater from 200 feet you would probably hit the ground regardless.

A different airplane might do something different but if you?re not into acro and spins etc. maybe you best not try this unsupervised.
 
Mile High Relic said:
Your original response might have been clearer if it said "whereas the other combination will have your nose pointed at the trees."
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Yes that's what I meant, but wasn't as clear as I should have been. Thanks for the detailed response. I just added `find straight road' to my next flight plan.
 
Russ McCutcheon said:
I took the Cobra Ball (RV-4) out tonight solo and thought I’ll give it a try, I started out in a nice slip holding heading with full left rudder, progressively letting the airspeed decay, finally it did not want to hold heading, the low wing was trying to raise, trying to find out what would happen I moved my fat thy out of the way the best I could for a little more aileron deflection, We were sinking fast but it was not stalled yet, decay the speed little by little tell it broke over the top faster than you can snap your fingers, I was not surprised by this, it was telling me it was headed for this, upside down now with full flaps, I pushed and continued the roll and recovered well below max flap speed.

I do lots of spins, stalls and acro, this did not surprise me, I could see where it was headed, recommend if your slipping on final and she tries to lift the low wing, relax the pitch, there was plenty of warning but when it went there was no buffet, it just let go, would it have spun? It doesn’t mater from 200 feet you would probably hit the ground regardless.

A different airplane might do something different but if you’re not into acro and spins etc. maybe you best not try this unsupervised.
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Interesting result Russ. I think yours is the first account I've heard of getting a real break and roll over when setting up a slip like this in an RV. My attempts at doing this in the RV-3 aligned with the results Bill McLean described in his RV-4 - that nothing really happened if the airspeed was slowly and progressively reduced. Mine would wallow around with the rudder to the floor, full aileron, and full aft stick, but wouldn't break and roll over, or even stall properly. Interesting how we can find different results among similar or same a/c types.
 
sandifer said:
Interesting result Russ. I think yours is the first account I've heard of getting a real break and roll over when setting up a slip like this in an RV. My attempts at doing this in the RV-3 aligned with the results Bill McLean described in his RV-4 - that nothing really happened if the airspeed was slowly and progressively reduced. Mine would wallow around with the rudder to the floor, full aileron, and full aft stick, but wouldn't break and roll over, or even stall properly. Interesting how we can find different results among similar or same a/c types.
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I was trying to simulate this as if on approach to landing so I was using full flaps, I could not tell if Bill was using flaps, where you using flaps? I have no idea if flaps up or down would change the result, just wondering.
 
Russ McCutcheon said:
I was trying to simulate this as if on approach to landing so I was using full flaps, I could not tell if Bill was using flaps, where you using flaps? I have no idea if flaps up or down would change the result, just wondering.
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It was years ago and I think I did it with flaps for the same reason (simulate landing), but don't remember for sure. My Pitts is another one that won't spin if you slowly pull the stick aft during a full power-off slip. But you can snap it from a slip if you pull it hard and then unload. Good way to dissipate energy on final. :D
 
Russ McCutcheon said:
I took the Cobra Ball (RV-4) out tonight solo and thought I?ll give it a try, I started out in a nice slip holding heading with full left rudder, progressively letting the airspeed decay, finally it did not want to hold heading, the low wing was trying to raise, trying to find out what would happen I moved my fat thy out of the way the best I could for a little more aileron deflection, We were sinking fast but it was not stalled yet, decay the speed little by little tell it broke over the top faster than you can snap your fingers, I was not surprised by this, it was telling me it was headed for this, upside down now with full flaps, I pushed and continued the roll and recovered well below max flap speed.

I do lots of spins, stalls and acro, this did not surprise me, I could see where it was headed, recommend if your slipping on final and she tries to lift the low wing, relax the pitch, there was plenty of warning but when it went there was no buffet, it just let go, would it have spun? It doesn?t mater from 200 feet you would probably hit the ground regardless.

A different airplane might do something different but if you?re not into acro and spins etc. maybe you best not try this unsupervised.
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The key here is that as soon as the plane stops holding heading, you've gone from a slip to a skid and the plane is yawing thus causing the break over the top at stall.

Skylor
 
skylor said:
The key here is that as soon as the plane stops holding heading, you've gone from a slip to a skid and the plane is yawing thus causing the break over the top at stall.

Skylor
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No, by moving my leg and adding the extra aileron I was able to hold heading but the airplane was fighting this. Either way we started from a slip, got to slow continued to intentionally do the wrong things and it broke over the top.
 
Russ, was that a slip or a skid? A skidded stall will definitely snap roll (in my experience with low wing planes of similar configuration to RV's). Never tried a slipped stall, but a snap roll seems way less likely for all the reasons mentioned in this thread.

Right cross wind is conventionally addressed with right wing down to turn into the wind and left ("Top") rudder used to align the nose. This is the conventional "wing down - top rudder" method and is a slip in my mind, not a skid.
 
gereed75 said:
Russ, was that a slip or a skid? A skidded stall will definitely snap roll (in my experience with low wing planes of similar configuration to RV's). Never tried a slipped stall, but a snap roll seems way less likely for all the reasons mentioned in this thread.

Right cross wind is conventionally addressed with right wing down to turn into the wind and left ("Top") rudder used to align the nose. This is the conventional "wing down - top rudder" method and is a slip in my mind, not a skid.
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It was a slip, not a skid, full left rudder and full right aileron, left wing high, right wing low, constant heading, when it had finally had enough the hi wing/left stalled and the low wing/right went over the top.
 
Russ: Thanks for this little bit. I use skid turn snap entries, but never have let the speed decay on the slips to stall...course, slipping for me is process because the amount of crosswind varies as I descend...so some, then more, then less....rarely am I close to the amount of slip authority at full rudder, so...but am looking forward what sounds as if it is a snap entry to one of the better wild rides...John N95JF (mount holding so far....!)
 
johnf_1 said:
Russ: Thanks for this little bit. I use skid turn snap entries, but never have let the speed decay on the slips to stall...course, slipping for me is process because the amount of crosswind varies as I descend...so some, then more, then less....rarely am I close to the amount of slip authority at full rudder, so...but am looking forward what sounds as if it is a snap entry to one of the better wild rides...John N95JF (mount holding so far....!)
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Cool John!
 
Full snap

When I was teaching in the Extra, with new- to- aerobatic students I would often demonstrate the snap in this scenario, just because it was so gentle.

Something that no one has mentioned so far is that if you allow the aircraft to continue rotating in the snap back to upright before recovering, there is minimal altitude loss- at least in the Extra - but the inexperienced will tend to stop somewhere between inverted and knife edge..
 
mine won't spin in a slip

I tried the extreme slip again with flaps, and my RV-4 would not spin, but bobbed and weaved like it did before and similar to what Eric Sandifer described in his RV-3. Either our techniques or aircraft are different than the those that were able to spin from a slip, and could be both. The calculated aircraft weight was 1303 lbs with C.G. 72.9 inches, which is almost the 50 percent point of the acceptable range. I began in level flight with engine idle about 10 knots above stall speed, adding rudder to max with opposite aileron to obtain the same heading. The nose would drop, but no clean stall or induced roll. On another attempt to try and make it stall, I increased some pitch, but had to reduce the aileron and raise the wing, holding full rudder to hold heading. If I have more than 45 degree bank with full rudder, the nose will pitch down and the aircraft gains speed, increasing the descent rate. It could very well be the difference in my aircraft with flat wing tips, and fences to improve acro characteristics, but it increased the stall speed about 3 knots.
Bill McLean
RV-4 Slider
Lower Alabama
 
Interesting. Every aircraft will have unique characteristics, the two seat Extras are terrible spin trainers, and harder to snap well, and it's very difficult to do crossover spins in them, whereas a two place Pitts does them very well.

I will surely be investigating all this when my -7 is finished, which I am hoping will be this year. I will put a video camera in it and see what more information I can bring!

Bill, I don't know if my plane will be ready for fall Sebring, but I wll be there to volunteer some, be great to see you! Looks like you are still having fun!:)
 
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