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Sideslipping an RV

howzat

I'm New Here
Being fairly new to RVs and the proud owner of an RV-7, I've not been able to get a consistent answer as to whether there are any restrictions or limitations on sideslipping on base or final to loose height. It's been suggested to me that it shouldn't be done, and/or shouldn't be done with any flap out. I'm not referring to a sideslip in the flare or short final in a crosswind, but something more sustained and likely at a (slightly) higher speed.
Any advice or guidance would be appreciated!
 
Being fairly new to RVs and the proud owner of an RV-7, I've not been able to get a consistent answer as to whether there are any restrictions or limitations on sideslipping on base or final to loose height. It's been suggested to me that it shouldn't be done, and/or shouldn't be done with any flap out. I'm not referring to a sideslip in the flare or short final in a crosswind, but something more sustained and likely at a (slightly) higher speed.
Any advice or guidance would be appreciated!

I sideslip my -6 frequently with full flaps all the way to the flare. I'm generally at 1.3x stall speed when I begin to come out of the slip. I've never experienced any adverse characteristics, and when I transition trained with Mike Seager (the factory transition CFI), he indicated that the RV-6 slipped very well and we practiced a few. An RV-7 could be different, but I doubt it.

Why not experiment at altitude to check the handling characteristics of your -7 with flaps, without flaps, and at different bank angles and speeds?
 
Why not experiment at altitude to check the handling characteristics of your -7 with flaps, without flaps, and at different bank angles and speeds?

Who suggested that you not slip an RV? What reason did they give? How much RV time did they have? Did they ever try it themselves?

I used to slip my RV-4 all the time with full flaps as well as clean. Never paid attention to the speed in the slip, though, as my attention was outside. I slip the -9A when I have to, but slips don't do as much in the -9A as they do in other planes.

Kyle's got the right idea, go try it at altitude. Personally, I doubt you'd spin it, but that might happen, so go find an RV instructor and have at it!

Ed
 
And please post your results!

I use to do nearly full control deflection slips in my cessna. I've slipped my 7A a few times although nothing even close to the control deflections I did with the cessna. When slipping the 7A, I didn't notice any unusual characteristics.
 
I have found slips in my rv are far less effective than the cessnas and pipers ive flown. Even with full rudder it just isnt that effective to me.
 
My 9A does not bleed energy nearly as well in a full slip as the 172, but with full flaps and a CS prop I really haven't needed it other than Phase I testing.
 
With a Constant Speed prop, the slipping is not always necessary BUT when one flys formation, sometimes it is needed. Over the past 20-years flying and more than 3,300 hours in my RV-6, I have slipped the aircraft MANY times including full rudder inputs. Very controllable and very similar to the 1XX series Cessnas but easier in the RV.
 
It?s hard

It’s really hard to slip an RV at cruise speeds. That big rudder is really hard to push out into the wind. I have pressed on it at cruise, never hard enough to endure a true slip.
 
Another RV-4 slipper here. I do it all the time with flaps down; I like remaining high until the runway's made.

Slips aren't as effective in an RV as factory planes simply because there's less, and cleaner, side area to add drag. Not *as* effective, but still effective.

Charlie
 
Try flying a -9 with a FP prop, you will learn to slip it. Although, as Ed said above, in the -9(A), it really doesn't do a whole lot.
 
Slow down

I think the people who say slips are not that effective in an RV are not doing it right. The rudder is big and the forces are large on the pedals. If you slow down close to final approach speed, you can fully deflect the rudder and it comes down very well.

-Andy
 
Go fer it.
I have to slip it into her every time l come home, because there are a few big trees on the end of my strip.

Don't matter much as there is a 1000 met rest usable strip.

But l come over the top at 70 kts and already slipin it in to er full flaps with it crossed up to th max.

Start gentle, practice it often ( it could save ya bacon one day) quarter flap and just increase flap and imput as ya get comfortable with it but slow down on ya approach speed.

When you get the hang of it it's a great way to view the runway on short final and l just kick it straight before touch down.

And it's fun, and ain't that flyin is all about?

Slip it into er cobber, you'll love it.
 
Has anyone gone and practiced stalls from a forward slip in an RV? In the 172 it just mushes with no buffet and with a roll tendency back toward leveling the wings, really a very benign stall condition that got me a lot more confident in forward slips to landing.

I imagine in the RV a forward slip to stall would still try to bring the wings level but the roll would be aggressive and would bring you over the top inverted.
 
-7 slips fine

I have slipped my -7 many times, where I fly there are 3 large flight schools and a very busy pattern and the tower may request a short approach to land you inside someone on an extended pattern.

The -7 slips fine to the left with flaps or no flaps, more difficult to the right for some reason and does take a fair amount of rudder pedal pressure.

I have never felt that the plane was on the edge of anything maneuverability wise and is very controllable. I do keep an eye on airspeed in the slip and you can descend at very high rates if you need to, not as much as my old Pacer but enough to be a useful maneuver when required.

I have never heard that you should not slip a RV, maybe someone is referring to the flip/wing drop issue discussed in the thread last year if you get too slow and uncoordinated controls in the pattern.
Figs
 
I think the people who say slips are not that effective in an RV are not doing it right.

Your thinking is wrong. Some folks don?t do it right and tack on extra speed which defeats the purpose of slipping but others simply have experience in other aircraft types that really do make the RV weak by comparison. Your frame of reference and experience may not include these many airplanes that truly put an RV to shame in the slip effectiveness department. IMO RVs only slip marginally better than Cessna trainers, which ain?t saying much. RVs do plenty of other things very well though. It can?t be everything.
 
Has anyone gone and practiced stalls from a forward slip in an RV? In the 172 it just mushes with no buffet and with a roll tendency back toward leveling the wings, really a very benign stall condition that got me a lot more confident in forward slips to landing.

I imagine in the RV a forward slip to stall would still try to bring the wings level but the roll would be aggressive and would bring you over the top inverted.

Simulate a landing configuration slip- power off, full flap, rudder to the floor, full aileron, 1.3Vso and start easing the stick back. Like so many other airplanes, the RV will end up with the stick on the aft stop, bobbing along refusing to spin or really do much of anything. But with too much speed sure you can yank the stick back and basically snap roll into a spin but that’s not a very realistic landing approach simulation. Lots of pilots tip toe around slips for fear of the dreaded uncoordinated stall/spin entry. No need. Just don’t turn a slip into a skid by removing the aileron before the rudder.
 
Well...

When you say 'not as good as...', you're kinda comparing apples and kumquats.

I learned to fly in a Luscombe 8A (no flaps), and slipping was the only way to increase descent angle. Obviously, slipping the Luscombe was more dramatic than the RV, but it has a much 'fatter' fuselage, bigger tail, struts, a lot more wing area (skin drag), etc. And the Luscombe would come down a lot faster than an fixed pitch RV, regardless of slipping. Is that a good thing? Only if you've lost the engine and you're 100 feet above a parking lot.

Luddite42, You say Simkinsona's thinking is wrong, and then you make his case. Whaaattt??
 
Luddite42, You say Simkinsona's thinking is wrong, and then you make his case. Whaaattt??

No. He made a blanket statement that basically said if you don?t think an RV slips well then you?re doing it wrong. That general thinking is wrong. I simply gave a qualified example for WHEN that might be the case (adding extra airspeed). Most certainly not true in all cases.
 
I don't like to slip because of the force on the rudder required is significant and I can't imagine thats a good thng for the rudder/airframe.
I've stop drilled lots of cracks on rudder skins, not sure if they are slip related but one of my good friends who used to slip a lot has multiple cracks while I've had none.
 
I think the people who say slips are not that effective in an RV are not doing it right. The rudder is big and the forces are large on the pedals. If you slow down close to final approach speed, you can fully deflect the rudder and it comes down very well.

-Andy

+1

I could do very steep approaches in my 9A with full flaps and full rudder. Sometimes it was preferred because the nose was so high, I had to slip to see the runway threshold.

Go practice it at altitude, it's a handy technique to add for very short landings.
 
Where the problem potential lies.

Hi,

No one has really explained why slipping may become a problem and why you probably got the advice.

First of all they slip well. However, depending on how the fuel tank was built and how much fuel is in the down wing could lead to an e.ngine stoppage. This happened in our 9. If your down wing tank has flop tubes this is unlikely to happen as it will still be able to pick up fuel

If the down wing tank as a standard pick up tube and it is low on fuel the fuel flows away from the pick up in the down wing. Of course it will take a few minutes for the carb to empty but FI may be affected by it pretty quickly.

So if you are going to slip, make sure either you are on the raised wing fuel supply, have plenty of fuel in the down wing is still taking fuel from that tank, or there is a flop tube in the down wing.


In our case the engine restarted soon after the wings had been levelled but the pilot got a nasty surprise when it stopped initially and then again when it started making power again.
 
No one has really explained why slipping may become a problem and why you probably got the advice.

First of all they slip well. However, depending on how the fuel tank was built and how much fuel is in the down wing could lead to an e.ngine stoppage. This happened in our 9. If your down wing tank has flop tubes this is unlikely to happen as it will still be able to pick up fuel

If the down wing tank as a standard pick up tube and it is low on fuel the fuel flows away from the pick up in the down wing. Of course it will take a few minutes for the carb to empty but FI may be affected by it pretty quickly.

So if you are going to slip, make sure either you are on the raised wing fuel supply, have plenty of fuel in the down wing is still taking fuel from that tank, or there is a flop tube in the down wing.

Yikes! I never even considered this condition. Thanks +++
 
Approaching home after a tank-draining cross country, I had the sudden inspiration to inspect the fishing crowd on a local reservoir. Lacking any semblance of planning, I was too close abeam to simply curl into a coordinated tight turn, plus not wanting to change track, I racked the -7 into a cruise speed slip to look steeply down.

The engine quit after several seconds. I had not thought to select the high-side tank. Just a reminder about basic airmanship should you hang ten coming down a long final.

Yes, RV-7s do slip, and mine carry the original -8 rudder.

John Siebold
 
RVs slip better than Ercoupes and Long EZs
Cherokee 180s slip better than RVs
Citabrias/Decathlons slip better than Cherokees
Stearmans and J-3s slip better than Citabrias
Pitts? slip better than Stearmans.
How ?well? you think RVs slip is all a matter of perspective. ;)
 
Fuel management

Yikes. I almost always slip to the left, in a left base-type of pattern. And I will now add a note to consider selecting the right tank in the pattern, and also try to arrive with most fuel in that tank.

The things we learn on this site!
 
Funny really

Interesting observation about unporting the left tank as it happened to one of my flying buddies on the way to Oshkosh. I am normally on the right tank in the pattern because 1) most patterns are left, 2) I tend to slip to the left (easier and not looking cross cockpit), and 3) when I use mogas for long Xcountry I fill the left tank and burn that off first (I fly from the left side) but I take-off and land with 100LL in the right tank (comfort factor :D ) which is part of my checklist.

Net result in my case is it all works out (more happenstance than intellect though).
Figs
 
Hi,

However, depending on how the fuel tank was built and how much fuel is in the down wing could lead to an e.ngine stoppage. This happened in our 9. If your down wing tank has flop tubes this is unlikely to happen as it will still be able to pick up fuel.

I thought ?flop tubes? were for negative g maneuvers. I don?t see how they help in a slip.
BTW, if you use the ?wing low (sideslip)? method for crosswind landings, you face the same issues.
 
The trap door that's added to the inboard tank rib to help keep fule in the inboard bay area nearest to the pickup tube .
 
...First of all they slip well. However, depending on how the fuel tank was built and how much fuel is in the down wing could lead to an e.ngine stoppage. This happened in our 9. If your down wing tank has flop tubes this is unlikely to happen as it will still be able to pick up fuel

If the down wing tank as a standard pick up tube and it is low on fuel the fuel flows away from the pick up in the down wing. Of course it will take a few minutes for the carb to empty but FI may be affected by it pretty quickly.

So if you are going to slip, make sure either you are on the raised wing fuel supply, have plenty of fuel in the down wing is still taking fuel from that tank, or there is a flop tube in the down wing.
...
What's it really matter? If you are slipping in the pattern, chances are good you are high and trying to lose some altitude. That is not a bad situation to be in, high on final, low on fuel, and a sputtering engine.

I slip almost every landing because i keep my patterns tight, and I have never had an engine so much as sputter.
 
In a 9, FWIW, I find that slips work really well. Alternatively, simply lowering the airspeed on final about 5 kts to about 1.25-1.3 Vso rather than my 1.3-1.35 Vso normal approach speed also helps shed altitude real fast and is my preferred method if close to the ground.
 
What's it really matter? If you are slipping in the pattern, chances are good you are high and trying to lose some altitude. That is not a bad situation to be in, high on final, low on fuel, and a sputtering engine.

Well... I've seen situations with thermals and downdrafts where the slip took care of the thermal, but then I needed power because of. sinker...
 
Slipping an RV

I have slipped my RV-6 for 23 yrs. with no adverse effects. Standard fuel pickups. Just watch it in base to final and don't get too slow. It will spin out in the opposite direction of the slip. Really a surprise.
 
Spin from Slips?

I have slipped my RV-6 for 23 yrs. with no adverse effects. Standard fuel pickups. Just watch it in base to final and don't get too slow. It will spin out in the opposite direction of the slip. Really a surprise.

This seems to be something that varies from pilot to pilot/plane to plane. I can pull my RV-8 into a stall while in a full-rudder slip (in either direction), and it does not have any tendency to spin. The key is that spin entry typically requires yaw motion such as a skidding turn or a "kick of the rudder" at the moment of stall. A steady slip does not do this. However, if you happen to stall at the moment you are kicking in the rudder for the slip, then you may enter a spin.

Skylor
RV-8
 
Seems counterintuitive but using full rudder deflection in a slip makes it more resistant to snapping out of a slipped stall than partial rudder. Full rudder yaw produces some elevator blanking and once you get to the point of full elevator, the rudder is blanked such that they combine to produce a very spin resistant condition.
 
It?s really hard to slip an RV at cruise speeds. That big rudder is really hard to push out into the wind. I have pressed on it at cruise, never hard enough to endure a true slip.

I'd be careful about trying to put in full rudder (or any other flight control surface) at cruise speeds! Do that above Va and you are asking for structural damage/failure.
 
Slipping with Flaps

I slip my RV-4 on almost all landings to the south a my home field. We have 60+ trees right at the north end of the runway to a 2700' grass strip. There are 40' trees about 300' from the south end. As soon as the trees disappear under the nose, I begin a moderate slip down to just before the flare. I end up using less than half the runway with this technique, but like the fact I have some excess distance in the event I'm not 100% on my game.

Sure, it doesn't slip anything like my J-3, but it still comes down quite well with full flap slips. And my experience is a stall from a slip will only result in the wings rolling towards level. If you continue to hold opposite rudder through and past the stall, it will indeed spin the other direction.
 
What's it really matter? If you are slipping in the pattern, chances are good you are high and trying to lose some altitude. That is not a bad situation to be in, high on final, low on fuel, and a sputtering engine.

I slip almost every landing because i keep my patterns tight, and I have never had an engine so much as sputter.


Bill, I am really surprised you asked why does it really matter!

You make assumptions about where people slip their aircraft, where they are trying to get into, the ability of the pilot to deal with a sudden engine our, possibly followed by an engine coming back to life when not expected.

Look up landing at Stanton in the Uk on google. The one with the light aircraft not the gliders. I tried landing there the other day and had I had either scenario happen there would be one less RV 4 in the world.

Basically it an up hill strip 600 metres long easy in an RV. But you have to land uphill even with a tailwind, and there are high power lines on the approach. You will see them on the video. Now bear in mind the aircraft in the video has a stall of 26mph so was approaching at about 40, this made it easily doable.

I tried two approaches in my 4, the first following the approach in the vid, the second coming straight in over the power lines with about 10 knots on the tail.

You will have noticed that there is a hangar right at the end of the strip, so in a go round you are not only trying to out climb the hill but also clear the hangar!

So there I was down to 60 on approach slipping to loose height, if the engine had stopped I would have no choices I would have crashed. So, this is why people need to know not to slip with the lowest wing supplying fuel.

We are not all blessed with 2400 ft asphalt runways, 1100 ft on grass is often common in the Uk, with trees at each end! You really don?t want the donkey stopping if it can easily be avoided by switching tanks if you know you are going to slip on short final.

Still love the EI commander!
 
EH?

What's it really matter? If you are slipping in the pattern, chances are good you are high and trying to lose some altitude. That is not a bad situation to be in, high on final, low on fuel, and a sputtering engine.

I slip almost every landing because i keep my patterns tight, and I have never had an engine so much as sputter.


Bill, I am really surprised you asked why does it really matter!

You make assumptions about where people slip their aircraft, where they are trying to get into, the ability of the pilot to deal with a sudden engine out, possibly followed by an engine coming back to life when not expected.

Look up landing at Stanton in the Uk on google. The one with the light aircraft not the gliders. I tried landing there the other day and had I had either scenario happen there would be one less RV 4 in the world.

Basically it an up hill strip 600 metres long easy in an RV. But you have to land uphill even with a tailwind, and there are high power lines on the approach. You will see them on the video. Now bear in mind the aircraft in the video has a stall of 26mph so was approaching at about 40, this made it easily doable.

I tried two approaches in my 4, the first following the approach in the vid, the second coming straight in over the power lines with about 10 knots on the tail.

You will have noticed that there is a hangar right at the end of the strip, so in a go round you are not only trying to out climb the hill but also clear the hangar!

So there I was down to 60 on approach slipping to loose height, if the engine had stopped I would have no choices I would have crashed. So, this is why people need to know not to slip with the lowest wing supplying fuel.

We are not all blessed with 2400 ft asphalt runways, 1100 ft on grass is often common in the Uk, with trees at each end! You really don’t want the donkey stopping if it can easily be avoided by switching tanks if you know you are going to slip on short final.

Still love the EI commander!
 
I slip my 8 all the time, if I'm high,and it works great. BUT, if I get below 71 KIAS, "something" starts stalling. Not sure what's stalling, but I make sure I'm never below the 71 KIAS if slipping. (Maybe one of you smarter guys can tell me "what's" stalling?:eek:
 
.

I slip my 8 all the time, if I'm high,and it works great. BUT, if I get below 71 KIAS, "something" starts stalling. Not sure what's stalling, but I make sure I'm never below the 71 KIAS if slipping. (Maybe one of you smarter guys can tell me "what's" stalling?:eek:

Hi, I am not claiming to be a smarter guy, in fact I am so dumb I can?t even understand your question.

What exactly are the symptoms you experience, stalling is when the wing stops flying and it does not appear that your term stalling refers to that condition?
 
I slip my 8 all the time, if I'm high,and it works great. BUT, if I get below 71 KIAS, "something" starts stalling. Not sure what's stalling, but I make sure I'm never below the 71 KIAS if slipping. (Maybe one of you smarter guys can tell me "what's" stalling?:eek:

You may want to check your airspeed against GPS speed landing on a no wind day if you have instrument logging abilities.

In a good slip the 71 kts you are seeing may not be real. The pitot won't be too bad but the airflow over the static ports can be quite different from straight flight and any previous calibration you did.
 
The pitot won't be too bad but the airflow over the static ports can be quite different from straight flight and any previous calibration you did.
Not sure if it should or not, but this is what I assume happens too. In the slip my ASI reads about 10 knots faster that when I straighten out. Thus, since my normal approach speed is about 55 kts, I try to keep my ASI reading above 65 kts or so while in the slip.
 
Hi, I am not claiming to be a smarter guy, in fact I am so dumb I can?t even understand your question.

What exactly are the symptoms you experience, stalling is when the wing stops flying and it does not appear that your term stalling refers to that condition?


Sorry Steve, that is the best I can describe. Full flaps, heavy slip, the airframe shutters like in a stall. I worded the statement the way I did, because I thought maybe one flap, or one aileron, or one wing was starting to stall. Tell you what. Next time I fly, I'll go up to a couple thousand feet, and really push it. Maybe I'll be able to figure out myself what exactly is shaking.
 
Interesting comments about airspeed. I slip my small tail six routinely downwind to final usually with half flaps when needed to lose excess altitude. I have always noticed what I thought was a tendency to accelerate (airspeed increases). I always attributed that to a tendency for the nose to go low while slipping.

Never thought that it might be a difference in airspeed sensing as the pitot static system is slipping.

Makes sense though as the airspeed does seem to drop back quickly as I remove the slip rolling final. Food for thought and further testing.

I do learn something pretty much every time I come on the site. Thanks
 
Sorry Steve, that is the best I can describe. Full flaps, heavy slip, the airframe shutters like in a stall. I worded the statement the way I did, because I thought maybe one flap, or one aileron, or one wing was starting to stall. Tell you what. Next time I fly, I'll go up to a couple thousand feet, and really push it. Maybe I'll be able to figure out myself what exactly is shaking.

Well that bit of extra description sounds to me like pre stall buffet, the aeroplanes way of telling you that if you do push it your in trouble if close to the ground. I would keep the airspeed a bit higher you are probably not doing 71 anyway because of the reasons discussed above.
 
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