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How does the RV slip?

swjohnsey

Well Known Member
I flew a flapless Citabria before buying a RV-3 and then a RV-4. I was using slipping a lot. Never really tried it with the RVs. The folks debating CS vs fixed pitch got me thinking.

When I was flying the Citabria the air speed indicator would reading accurately during a slip. Not so much on Cessna 150s and 172. The Citabria had pitot and static on the strut.

I now mostly fly the RV-4 with IO360, Hartzell CS, I want to explore slipping some. Any pitfalls to watch for. The Midway movie got me thinking.
 
Do it

I slip my -4 often, although the results are not as pronounced as my 46'BC12 did, similar to your Citabria. The -4 will drop like a rock if you get slow and slip, so be aware. I mostly do forward slips in the -4 when I am hot and need some braking action in the pattern.
 
I slip my -4 often, although the results are not as pronounced as my 46'BC12 did, similar to your Citabria. The -4 will drop like a rock if you get slow and slip, so be aware. I mostly do forward slips in the -4 when I am hot and need some braking action in the pattern.

Slips help, but IMO, like the previous poster said, th best way to really steepen your glide path in an RV is to get the flaps out and get slow. At 60 knots or less, my glide angle is steep. Add in a bit of a slip and it gets really steep. Obviously, something to get comfortable with at altitude first.
 
I've had an RV-4, fixed pitch, and an RV-8, constant speed. Both of them would do a good imitation of a brick in a slip, but in the -8, hardly necessary with full flaps and the constant speed. Lots of control authority at low speeds in both.

Go up to altitude and do some very aggressive slips, both directions, right up to stall so you get familiar with what the plane will do. You certainly don't want to depart controlled flight at low altitude, but my guess is that you'll have so much descent capability that you'll never need to get close to the limits.

And don't forget about your fuel selector in a prolonged slip cause you can unport the fuel pickup.
 
Ain't like a Cub, but it slips ok.

Something I've never checked at altitude; the scenario is minimum fuel in the selected tank, then slipping with that tank on the downhill side. Anyone unported the tank, and got a power interruption on short final?

I think most pilots typically slip to the same side every time, sort of like being right or left handed. If I anticipate a slip, I'll set up the feed on the right tank, because I usually slip to the left. I wonder if I'm being overly cautious.
 
Ain't like a Cub, but it slips ok.

Something I've never checked at altitude; the scenario is minimum fuel in the selected tank, then slipping with that tank on the downhill side. Anyone unported the tank, and got a power interruption on short final?

I think most pilots typically slip to the same side every time, sort of like being right or left handed. If I anticipate a slip, I'll set up the feed on the right tank, because I usually slip to the left. I wonder if I'm being overly cautious.

I have a preferred side but I generally slipped in the same direction I would be using for my crosswind correction. The RV-4 with CS comes down like a brick with no power. Mostly curiousity.
 
RVs just don't have the drag and large side area to exploit in a slip compared to rag and tube planes. RVs also run out of rudder well before the aileron in a slip. Slips help some, but the effect is quite weak compared to planes that really slip well such as J-3s, Stearmans, and Pitts.
 
Ain't like a Cub, but it slips ok.

Something I've never checked at altitude; the scenario is minimum fuel in the selected tank, then slipping with that tank on the downhill side. Anyone unported the tank, and got a power interruption on short final?

I think most pilots typically slip to the same side every time, sort of like being right or left handed. If I anticipate a slip, I'll set up the feed on the right tank, because I usually slip to the left. I wonder if I'm being overly cautious.

I've tried that in my 9A and haven't yet unported a tank. I didn't get real enthusiastic about it though.
 
Used to fly an -8 off a 2000ft grass strip. Slipped virtually every landing, per primary instruction,
 
I've tried that in my 9A and haven't yet unported a tank. I didn't get real enthusiastic about it though.

I've tinkered with a little bit of this testing, at altitude, and have unported the downhill tank. I forget the actual numbers but there was something like 2gal in that tank and the slip was most exceptionally enthusiastic :).
 
I have a preferred side but I generally slipped in the same direction I would be using for my crosswind correction.

Same here - it's been a while since I flew a Citabria, but my general procedure after turning final was:

  • Establish crab for crosswind. High? Power off if not there already.
  • Still high? Establish sideslip for crosswind.
  • Still high? Exaggerate sideslip into forward slip.

I found this to provide a nice continuum of actions with which to manage the approach.
 
Ain't like a Cub, but it slips ok.
I think most pilots typically slip to the same side every time, sort of like being right or left handed. If I anticipate a slip, I'll set up the feed on the right tank, because I usually slip to the left. I wonder if I'm being overly cautious.

I do the same thing, generally land with the right tank selected anyway as most patterns are left. I have had my buddy unport a tank slipping on final and the engine quit on short final so he landed without power.
Figs
 
I've tinkered with a little bit of this testing, at altitude, and have unported the downhill tank. I forget the actual numbers but there was something like 2gal in that tank and the slip was most exceptionally enthusiastic :).

Yes, you can unport the down tank with aggressive slip or in a very steep turn with 2-3 gallons. But there are plenty of seconds to detect it.
 
In my Fixed Pitched 9a in the first 28 hours, slips have been a very good tool to have in the tool box when coming in a bit high.

I will slow down get flaps out first, then slip.

One thing my buddy/CFII/RV Owner/Aerobatic mentor showed me though, was the reason to slip right rudder, left turn and left rudder right turn and why.

RV's will spin, and by doing the above if you do get slow, instead of a spin they stall upright vs spin. Obviously we did this at altitude with a very competent pilot while also demonstrating base to final stall.
 
frequently

I frequently (more often than not) slip the 7 in on base to final. Before I enter the circuit i always select the high tank (right tank in the left circuit) to allow me the capability of an aggressive slip without unporting the tank.

The 7 slips well and allows a tight circuit without the application of any power from base to touchdown. Nice habit to have in a single engine aircraft.
 
I use the slip in my 9 but it is almost useless with the long wing. I was doing a fly-by on a new home at lower than usual altitude and wanting to see better out the window while circling. I un-ported my fuel feed. Didn't last long but sure got my attention. I think I still had 6-8 gals in that tank as well.
 
I use the slip in my 9 but it is almost useless with the long wing.

Interesting... I find my -9 slips very nicely. That said, what also works well, as alluded to in an earlier post above, is to slow the approach down. 50-55 kts on final vs my normal approach speed of 55-60 kts usually does the trick.
 
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Thought

Ain't like a Cub, but it slips ok.

Something I've never checked at altitude; the scenario is minimum fuel in the selected tank, then slipping with that tank on the downhill side. Anyone unported the tank, and got a power interruption on short final?

I think most pilots typically slip to the same side every time, sort of like being right or left handed. If I anticipate a slip, I'll set up the feed on the right tank, because I usually slip to the left. I wonder if I'm being overly cautious.

Seems to me about the only time I slip is because of WAY to much energy so IF the engine stumbles I?m covered and will have to continue slipping anyway.

For me, if I?m on a left base I slip into the turn and vice versa a right base. That way I just hold or increase bank and step on the top rudder.

Works for me.

Just my quick take away.
 
RV-12's slip great

I can shove in a full slip (either direction) and go from 500 fpm descent rate to about 1200 fpm. Not only is it very controllable, and another tool to have in your flight bag, but it's fun too.
 
Max speed

Is there a max slip speed? I would guess one would have to stay below maneuvering speed for the landing weight, but does maximum flap extension speed come into consideration?
 
Stall from slip

A caution from my experience. I?ve tried stalling a Citabria from a full slip and it was quite benign - very little tendency to spin. In my 7A the experience was very different - it drops a wing aggressively when I would deliberately stall it from a slip (at altitude!!). Same response slipping either direction. I wouldn?t want to do that close to the ground.

Scott
 
RV-3 through RV-14 are just airplanes and can be slipped the same as any plane. You can slip a B767. However an RV is less draggy than a Citabria, but slipping does add drag. RV full flaps are good for slight stall reduction and drag. Slipping should NOT be required for normal operations.

Plan to arrive over the obstacle / fence / threshold on speed, full flaps and no slip should be needed. If you are having speed control issues on short final it is you not the plane. I don't have a lot of fixed pitch RV time which might have less drag and more residual thrust than a CS prop. Still I never found it hard to plan to get it slow. One RULE "It is hard to go down and slow down". You need to get the plane slowed and some flaps in before leaving pattern altitude.
 
I've done some overly aggressive slips in the past on a variety of aircraft and in my experience you can have the inside wing stalled to the point that it is buffeting enough to really shake the aircraft but it isn't until your recovering from the slip that the air raft can stall..particularly if you were slipping in a nose high slip...they key is that if your slip is super aggressive make sure you change the angle of attack quickly as you take it out of the slip. Now I want to make it clear that I have not tried this in an RV so if you wish to try it make sure you have a couple of thousand feet below you. My gut tells me you probably won't have enough rudder to really be able to aggressively slip an RV. :D
 
I flew a flapless Citabria before buying a RV-3 and then a RV-4. I was using slipping a lot. Never really tried it with the RVs. The folks debating CS vs fixed pitch got me thinking.

When I was flying the Citabria the air speed indicator would reading accurately during a slip. Not so much on Cessna 150s and 172. The Citabria had pitot and static on the strut.

I now mostly fly the RV-4 with IO360, Hartzell CS, I want to explore slipping some. Any pitfalls to watch for. The Midway movie got me thinking.

Also flew a Citabria for several years before my RV8. The very first plane that I flew was a J-3. I slipped them both all the time and I now slip the 8 any time I need to shed some extra altitude. Never a problem.
 
I probably slip my 8 about half the time, BUT, at 71 KIAS, I get a stall buffet. So I never get slower than the 71 Kts, (unless I don't need a slip) See Post 25.
 
RV6A with metal FP prop..... Slips very nice but does not have the drag of the Warrior. Keep the nose down during a slip, if you let it lift and increase the AOA, the top wing will stall and pull you level on the way over to a spin if you don't aggressively push, and center the rudder....iow.... release the rudder pressure.

Don't confuse this with a skid.... the event of pushing on the lower rudder to keep from overshooting a turn to final. The LOWER wing will stall with little chance of recovery.
 
Stall/Spin in the Base Turn

SLIP

It's difficult to get the airplane to depart controlled flight (stall/spin) in a slip. Note the "ratcheting" effect as the airplane stalls. In this case, I'm in a sustained deep stall condition with full inside slip input (left aileron, right rudder during a descending left turn):

https://youtu.be/RtwS_vXQukk

Here is the same maneuver looking out the back of the canopy. Note the extensive tail buffet:

https://youtu.be/aqJTLEpE8sY

Here's another example looking forward...in this case, I reduce alpha before a spin (snap roll) develops fully. In other words, you really have to work hard to depart the airplane in a slip:

https://youtu.be/SD-EiHg2nBk

One more example...note multiple "nose bobs" (stall) as I've got the stick full aft:

https://youtu.be/uMEVEZMUDXY

SKID

On the other hand, if you try to recover from a low-altitude, over-shooting final by "skidding" the airplane (rudder applied in the direction of turn, and "outside" aileron applied to limit bank angle); things get interesting when you depart controlled flight. Note how quickly the airplane snap rolls underneath at stall:

https://youtu.be/h5OFuQaYs1o

Here is the same maneuver, rear view. Note extensive horizontal stab buffet:

https://youtu.be/4BHcBmQ0aoo

Note with a relatively quick recovery, 500' was lost during a typical skidding departure. If, I reduced AOA earlier in the roll, the airplane would stop rolling, albeit at a very high bank angle and very nose low condition that may require even more altitude to recover from:

https://youtu.be/tGItkZzTLUE

In both cases (slip and skid), the further aft the CG, the less static margin you have which means less natural stall warning (buffet) and quicker departure. Cross-controlled stall discussion applicable to RV's begins on page 342 in the transition training manual available in the sticky at the top of the safety page. Exercises applicable for dual instruction with a current and qualified instructor are discussed on page 390.

Merry Christmas gang,

Vac
 
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Wow! Thanks for the videos. Beautiful cold clear morning, I'm going out to see just how this RV-4 slips. I'm a little nervous about slips with flaps, though.
 
Folks talking about a full forward slip and getting STALL BUFFET... scares me. :eek: You should not be near stall in a slip or feel stall buffet. The buffet you are likely feeling (if IAS approach speed, above stall) is turbulent airflow coming off the side of the fuselage, buffeting the whole airframe ...

Slipping does not increase stall speed. The aerodynamics of the wings do not change with a slip. IAS may have some error in a slip but it is NOT from the pitot tube but static port. If you have dual static ports the error should be small (subject to phase 1 flight test calibration).

Not sure what "aggressive" slip is. A forward slip is full rudder, aileron to track and pitch to maintain approach IAS. This is standard.... I guess not aggressive is less than full rudder. If you are timid about using full rudder than you will not have full effective use of this normal maneuver to lose altitude w/o gaining speed.

Bottom line stall IAS in slip is similar to iAS in coordinated flight except for small IAS error AND high wing with down aileron is at higher angle of attack, so it will stall first and plane will snap roll over in the direction of the high wing. That affects stall speed slightly. You should be no where near stall when you do fwd slip on approach to lose altitude without gaining air speed.

The YT videos on previous post are fun. However I wonder about altitude lost? It look like the recoveries were very quick with min altitude loss. Except CFI no pilot training requires spin training. It would be good to go practice full stalls is skids and slips. The RV-4 with a passenger can get some weird control reversals near aft CG. I would not do this with a messenger in a RV-4 or RV-8 without chutes.... However the videos show HOW NICE RV's are to fly and honest, letting you know they are about to stall and having such a benign docile characteristic when they do.
 
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Angle of Attack Vs. Bank and Yaw

SLIP

Here's another example looking forward...in this case, I reduce alpha before a spin (snap roll) develops fully. In other words, you really have to work hard to depart the airplane in a slip:

In the first and second video, the snap roll/spin is the result of centering the ailerons and relaxing the bank while keeping rudder applied. You generally need yawing motion to induce a spin and by flattening the bank with rudder still applied you are no longer maintaining the slip and the nose begins to yaw right while the wings are still at critical angle of attack. Also, the drop the of the nose preceding the "snap" increases rudder effectiveness, further increasing right yaw...

Skylor
 
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Folks talking about a full forward slip and getting STALL BUFFET... scares me. :eek:

Why? They were doing this deliberately at altitude to observe the behavior of the slip as AOA is increased up to potentially full aft elevator. Most airplanes are quite stall/spin resistant in a full slip while slowly increasing elevator to full aft, but nothing wrong with learning how your particular airplane behaves. I know of a Pitts pilot who killed himself spinning in on approach from a slip. The only real way to do that is to neutralize the aileron before you've removed the rudder. Even the Pitts is very stall/spin resistant in a slip.
 
Hi Skylor,

I'm actually maintaining full inside aileron during the departure sequence (to extent that I can). I had some spare gas today, so I flew three intentional departures using the same handling technique as the old videos that you are referring to.

What I think is occurring is roll coupling at high alpha (think high AOA rudder roll in a jet). There is sufficient stability to momentarily reduce alpha during the sequence, even though the stick is maintained full aft (nose bobbing)--which accounts for the ratcheting motion prior to the spin actually developing. I left full left aileron and full right rudder through the incipient stage of the spin and allowed the spin to wind up a bit. I'm working hard to force the airplane to depart in the slip--it would be difficult to miss the extensive aerodynamic warning the airplane is providing. The airplane (RV-4) weighed 1375 lbs, with the CG at 70.65" aft of datum:

https://youtu.be/I6tBNnoaB6w

Aerodynamically, if there is something else going on here at this weight/CG condition, I'm definitely open for critique or discussion! I may also be missing any engine/propeller effect that may be at play. Also entirely possible I’m ham-fisting something...wouldn’t be the first time.

Cheers,

Vac
 
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Skylor/Luddite:

I ran an additional test today as I was concerned my elevator input in yesterday's example may have been too rapid. Today's test conditions were similar to yesterday's and RV-4 gross weight was 1366 lbs, CG at 70.65." I pulled my left leg out of the foot well to be sure the stick reached the lateral limit, and then applied slow elevator input with stick against the lateral limit while maintaining full opposite rudder:

https://youtu.be/DExPobxNyIE

In other words, I'm able to induce a departure without neutralizing ailerons whilst maintaining rudder input (i.e., sufficient yaw for a spin to develop). Obviously aircraft specific performance, with extensive aerodynamic warning. Thoughts on this departure sequence? It appears to me that there is sufficient yaw as a result of rudder input at high alpha + adverse yaw to induce some roll coupling prior to departure. I appreciate the critique. I'm always trying to collaborate to improve or correct the discussion in the training manual.

v/r,

Vac

P.S. RV's slip just fine. Forgive the deep dive.
 
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When I was talking slip I meant cross controlled, I never even considered a skid. Don't think I ever deliberately induced a skid. Is there ever any reason to?
I did some slipping in the RV-4, no problem, air speed indicator is accurate during slip. I'm going to try some landing using slip instead of flaps. With the C/S prop I have to set up something artificial to be too high.
 
Skylor/Luddite:

I ran an additional test today as I was concerned my elevator input in yesterday's example may have been too rapid. Today's test conditions were similar to yesterday's and RV-4 gross weight was 1366 lbs, CG at 70.65." I pulled my left leg out of the foot well to be sure the stick reached the lateral limit, and then applied slow elevator input with stick against the lateral limit while maintaining full opposite rudder:

https://youtu.be/DExPobxNyIE

In other words, I'm able to induce a departure without neutralizing ailerons whilst maintaining rudder input (i.e., sufficient yaw for a spin to develop). Obviously aircraft specific performance, with extensive aerodynamic warning. Thoughts on this departure sequence? It appears to me that there is sufficient yaw as a result of rudder input at high alpha + adverse yaw to induce some roll coupling prior to departure. I appreciate the critique. I'm always trying to collaborate to improve or correct the discussion in the training manual.

v/r,

Vac

P.S. RV's slip just fine. Forgive the deep dive.

Interesting thread, and watching the video I was interested in the AoA tone throughout the maneuver. I have the dynon AoA pitot on the left wing and the thread indicates that in the slip the high wing will reach critical AoA first which in my case would generally be the right wing. How would this impact the AoA tone I receive and in particular the stall onset point of the AoA system? As I am generally head/eyes out when slipping on final the AoA tone is one of my Wake-Up calls if I get too slow:)
Sorry if a dumb question.
Figs
 
Figs,

Great questions.

First, a good rule of thumb for the coefficient of pressure pitot/AOA probes is that they can handle up to about 6 degrees of sideslip. I find I run out of rudder (generally) before I run out of tone in the RV-4.

Second, there are two tones in the video; they are being generated by systems we built that generate performance AOA and energy cues in addition to progressive stall warning. All of our work is on our website at http://www.flyonspeed.org (non-profit, volunteer, open source group).

Specifically, yes, the high (right wing) is stalling first--hence the ratcheting behavior in the departure sequence. My Dynon probe is mounted in the RV-4 plan pitot location under the left wing and there is a second, Alpha Systems probe mounted on the left aileron inspection plate as well, so in both cases any stall warning provided by either probe may be "optimistic" in a left slip. We've got a calibrated test boom that we can mount on either wing tip; so getting some comparison spin data is on the list of things to do to test that thesis and quantify it.

Additionally, the quality of the AOA tone performance is going to be affected by sideslip angle. I can't specifically quantify how much, as we haven't completed that testing yet either--but the 6 degree rule of thumb comes from wind tunnel test and correlates with what we've observed so far in flight. So, you are spot on with your "not too slow" game plan :)

My 2 cents would be to adjust your system to provide 5-7 MPH/KTS of stall warning tone to build a margin and realize the margin is probably less in a left slip. You could test that by flying a cross-controlled stall as I am in the video and noting the difference in time between hearing stall warning and that first nose bob. If you do, keep in mind the rate of back stick application will affect that result. If you pull hard enough, fast enough, you'll "beat" your stall warning system and stall before you hear the warning tone.

FWIW, we learned testing our first generation AOA tone generator that Dynon AOA calibrations vary from airplane to airplane; so your's is unique and the only way to know for sure is to flight test. Also, if you ever re-calibrate, that will reset your baseline and you'll have to re-test. The first test I'd run is to determine the amount of stall warning you have with your tone selection in a normal, straight-ahead stall and go from there.

Also, in the last video you probably noted that the airplane effectively stalled 4 times before I was able to force it into a spin. In other words, in a slip (left turn, left aileron, right rudder) the airplane is highly spin resistant, so even if you ham-fist it into a stall in the base turn, it will give plenty of aerodynamic warning. I.e., RV's slip great.

In a skidding departure the airplane will immediately roll (spin) at the first stall; which is why this is the last thing you'll want to try in an overshooting final turn.

Cheers,

Vac
 
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To answer the OP's question, you press on the left rudder and give it right aileron, just make sure you are above the stall speed. To slip the other way, you step on the right rudder and give it left aileron.

(Sorry, I just couldn't help myself.)
 
Why? They were doing this deliberately at altitude to observe the behavior of the slip as AOA is increased up to potentially full aft elevator.
Sure do stalls in a slip or skid at altitude. That is not what I was reading. However stalls or slips in uncoordinated flight in the pattern is still killing pilots. FAA Pilot Std may be for the detriment do not require stalls intentionally uncoordinated. All my students I have the option to do one lesson in the Aerobat for full stalls, spin entry and spin recovery, with chutes and jettison-able doors.

Most airplanes are quite stall/spin resistant in a full slip while slowly increasing elevator to full aft, but nothing wrong with learning how your particular airplane behaves. I know of a Pitts pilot who killed himself spinning in on approach from a slip.
No argument about stability and docility of RV's but some planes (T-6) will KNOCK YOUR HEAD on the side of the canopy if slipping into a full stall. Not all planes snap roll gently. I have about 700 hrs in RV's... they are great honest planes for sure. The NACA 2313.5 airfoil and frise ailerons makes the plane very docile and controllable into the stall.

No argument about training and practicing. I'm a CFI and do aerobatics. As you know Pvt, Commercial, ATP only requires stalls (coordinated flt) and stall avoidance and awareness as part of the PTS (now ACS). I agree practice of full stalls in slip or skid, entry into insipid spins and actual spin recovery is good training (with safety in mind). However historically due to a lot of training accidents FAA removed the requirement to do actual spins and spin recovery, except for CFI's. It is about stall awareness and avoidance and stall recovery (in coordinated flt). I spun my RV-4 and it was exciting. I don't recall but it was almost a full turn to come out. I would never spin it with aft CG. I recall reading an RV stall spin "loss of control" accident. The report mentioned the plane had aft CG. Yes RV's are docile but a stall at low altitude in uncoordinated flight is bad.

The only real way to do that is to neutralize the aileron before you've removed the rudder. Even the Pitts is very stall/spin resistant in a slip.
I would hesitate follow your above instructions on what is most important. Ref FAA Airplane Flying Handbook FAA-8083-3B Chpt 4. tells you (for most SE GA planes) first thing is forward stick as required to reduce angle of attack. Then it says roll wings level, recover and add power. I would use some rudder as required (if entering incipient spin or in a spin - i.e., auto-rotation). Agree neutral aileron at first but by all means roll level before recovery with aileron. When there are arguments what is first, I say do them all at the same time. If in a fully developed spin typically it's idle power. Power in stall recovery depends on power-on or power-off stall.

My point is will not stall if at 80MPH (1G load factor) in a full slip or skid with the plane shaking like a wet dog drying off. That buffet is not a stall buffet. I am very comfortable stalling in a full slip or skid (as safe altitude). I intentionally pull excess back pressure at the top of a loop and induce a stall. Nothing happens it just shakes. Release back pressure and it fly's again. Done it many times. However stall spins low to the ground in the pattern accident , FAA/NTSB terms "loss of control" LOC, is still an all too common accident. I just renewed my CFI and FAA is big on reducing LOC which is one of the biggest causes of accidents.

Stall speed increase in a slip or skid - Just to restated, NO not really, but a little as I mentioned, high wingm(down aileron) is at higher AOA. In full slip stall the plane will roll toward the high wing (or direction of the rudder) because the higher wing stalls first. Inboard section of wing (the higher one) is blanketed as well. It does not increased stall just less lift. IAS can change due to static port error which might cause IAS read high or low depending on direction of slip, especially if the plane has only a single static port on side of fuselage (as some certified GA planes have). So adding a few MPH on slip is OK, and actually adding speed adds drag and decreases your glide ratio. You want to increase speed to lose altitude, as long as you can bleed the speed before you flare.
 
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Slip with flaps

I know of a cessna 170 that you don?t want to slip with full flaps. A small slip will spin the plane immediately. Luckily i had a good instructor when I was high on final and started a slip and he saved our lives. Later he demonstrated at altitude. Do any rv planes have this tendency?
 
I know of a cessna 170 that you don?t want to slip with full flaps. A small slip will spin the plane immediately. Luckily i had a good instructor when I was high on final and started a slip and he saved our lives. Later he demonstrated at altitude. Do any rv planes have this tendency?

Must have been misrigged.

The reason you are not supposed to slip a 170/172 with full flaps is because with 40? of flaps in the HS and elevator are blanketed and the nose starts to hunt up and down, which could be bad close to the ground. Not really a big deal but not steady state either.
 
172s

Must have been misrigged.

The reason you are not supposed to slip a 170/172 with full flaps is because with 40? of flaps in the HS and elevator are blanketed and the nose starts to hunt up and down, which could be bad close to the ground. Not really a big deal but not steady state either.

I slip 172s all the time. They hunt a little, but I am never in them for very long. If you had one that would tuck and roll, must have beed mis rigged..

Cross wind landings are a forward slip or uncoordinated flight. It is all a matter of degree.
 
Skylor/Luddite:

I ran an additional test today as I was concerned my elevator input in yesterday's example may have been too rapid. Today's test conditions were similar to yesterday's and RV-4 gross weight was 1366 lbs, CG at 70.65." I pulled my left leg out of the foot well to be sure the stick reached the lateral limit, and then applied slow elevator input with stick against the lateral limit while maintaining full opposite rudder:

https://youtu.be/DExPobxNyIE

In other words, I'm able to induce a departure without neutralizing ailerons whilst maintaining rudder input (i.e., sufficient yaw for a spin to develop). Obviously aircraft specific performance, with extensive aerodynamic warning. Thoughts on this departure sequence? It appears to me that there is sufficient yaw as a result of rudder input at high alpha + adverse yaw to induce some roll coupling prior to departure. I appreciate the critique. I'm always trying to collaborate to improve or correct the discussion in the training manual.

v/r,

Vac

P.S. RV's slip just fine. Forgive the deep dive.

Vac,

Today I went up and did some more slipping stalls in my RV-8. In general, the behavior was similar to your earlier videos; when the plane reaches stall, there is some "ratcheting" and nose bobbing, and after a hand full of bob and ratchet cycles the plane eventually broke into an incipient spin.

I was at ~ 1650 lbs, CG 79.3 (my range is 78.7- 86.82). I did these with full flaps, idle power, and full rudder. Some observations:

1. As I approached the stall the ailerons clearly lost some effectiveness which required increased aileron input to prevent roll/yaw.

2. In the stall, the amplitude of the nose-bob motions and ratchet motions were not consistent from cycle to cycle and generally seemed slightly divergent.

3. Initially there is absolutely no tendency to break into a spin. This is consistent with numerous previous attempts at this.

4. As the amplitude of the bobs and rolls increase during the "falling leaf", there begins to be some yaw in the direction of the rudder. Eventually this is significant enough to induce a spin.

5. You really have to work at it and stay stalled a long time (with slip inputs) before the plane wants to spin.

Don't fear the slip!

Skylor
 
I would hesitate follow your above instructions on what is most important. Ref FAA Airplane Flying Handbook FAA-8083-3B Chpt 4. tells you (for most SE GA planes) first thing is forward stick as required to reduce angle of attack. Then it says roll wings level, recover and add power. I would use some rudder as required (if entering incipient spin or in a spin - i.e., auto-rotation). Agree neutral aileron at first but by all means roll level before recovery with aileron. When there are arguments what is first, I say do them all at the same time. If in a fully developed spin typically it's idle power. Power in stall recovery depends on power-on or power-off stall.

You misunderstand, again. I was referring to the fact that the only easy way to spin out of a slip in the Pitts is to neutralize the aileron before you?ve removed the rudder, which turns the slip into a skid, which easily produces a spin if you have sufficient AOA. Lots of airplanes exhibit this characteristic. I was not talking anything about spin recovery technique. Again, everyone should be aware of how their specific airplane behaves.
 
Several posts here miss the point. It?s just to understand the characteristics of the airplane and not fear the unknown.
 
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