Sideslipping an RV - Page 5

WAM120RV · #41 02-22-2018, 10:12 AM

Quote:

Originally Posted by N941WR

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!

BillL · #42 02-22-2018, 11:22 AM

Quote:

Originally Posted by bkervaski

Yikes! I never even considered this condition. Thanks +++

I put the flapper doors in both tanks (-7) to help address this with low tanks as suggested by Stephen Christopher.

Maxrate · #43 02-22-2018, 12:32 PM

http://www.airbum.com/articles/ArticleSlips.html

Great old article by Budd on the forward slip to landing.

donaziza · #44 02-22-2018, 07:02 PM

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?

WAM120RV · #45 02-23-2018, 01:00 PM

Quote:

Originally Posted by donaziza

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?

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?

az_gila · #46 02-23-2018, 01:09 PM

Quote:

Originally Posted by donaziza

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?

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.

alpinelakespilot2000 · #47 02-23-2018, 03:21 PM

Quote:

Originally Posted by az_gila

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.

donaziza · #48 02-23-2018, 10:31 PM

Quote:

Originally Posted by WAM120RV

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.

gereed75 · #49 02-24-2018, 07:38 AM

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

WAM120RV · #50 02-24-2018, 10:32 AM

Quote:

Originally Posted by donaziza

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.