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dave.saylor.aircrafters(a
Guest

Posted: Sat Mar 02, 2013 9:37 am Post subject: RV-10 Stall Characteristics (what just happened here?)

Last weekend I took some folks on demo rides.  All are -10 builders,

not yet flying.



On one flight, I had one big guy in the back seat.  My CG range is 8.4

to 16.8 (inches aft of the wing leading edge).  My CG on takeoff was

14.4--I ran the number before we departed because I knew the CG was

"aft-ish"--and the weight was 2614 lbs.  Years ago during phase 1 we

loaded the plane at aft CG, max gross, and did some stalls.  I don't

recall anything strange at all about those maneuvers.



First, I demonstrated an approach stall, which I've done many times.

My normal recovery is just to add a little power, stick neutral if

necessary, and the plane just flys out.  On the first stall, that's

just how it went.



Of course then it was time for a little "Watch this!"...



Actually, I wanted to demonstrate the AOA audio warning,

"Angle-Angle-Push", which was kind of faint on the first stall.  So I

let the stall develop further, keeping wings level with the rudder.

The wings rocked a bit but nothing serious.  The nose stayed straight

ahead.  Then, the nose pitched WAY down.  I added power to break the

stall and fly it out but there was no change.  It felt like we were

descending, not flying. It felt like we were about 45* nose down, but

the EFIS logs didn't capture anything that extreme.  I was concerned

about entering a spin.  So was the guy in the front seat--he said so

as it was happening...I added more power, stick neutral, and still the

nose was pointed down.  I kept the wings more or less level but at

this point things seemed out of the ordinary so I got more agressive

with the controls.  I pushed forward, adding more power.  The plane

then seemed to fly, and I seemed to be going pretty fast, but I didn't

look at the airspeed.  I pulled up gently and the controls eventually

started feeling normal again.  The EFIS logs showed the whole event

lasted less than 10 seconds--two data captures--but it sure seemed

longer.  We lost about 300 feet.



I spoke to another -10 owner who has a lot of acro and formation

experience.  He said, yeah, it'll do that...he concurred that from a

deep stall, an RV-10 requires extra effort to break it.  That's

probably not a huge surprise if you think about it and expect it, but

in this case it gave me (and unfortunately my passengers) a little

concern.



I'd be interested to hear if others have had similar experiences, and

if anyone has an explanation for what's going on aerodynamically.



Dave Saylor

831-750-0284 CL

jjessen01

Joined: 27 Sep 2010
Posts: 50

Posted: Sat Mar 02, 2013 9:49 am Post subject: RV-10 Stall Characteristics (what just happened here?)

Nice job getting out of that situation, Dave. Glad you are still with us!



John J



On Mar 2, 2013, at 9:35 AM, Dave Saylor <dave.saylor.aircrafters(at)gmail.com> wrote:



 	  Quote: 	
		   

 

 Last weekend I took some folks on demo rides.  All are -10 builders,

 not yet flying.

 

 On one flight, I had one big guy in the back seat.  My CG range is 8.4

 to 16.8 (inches aft of the wing leading edge).  My CG on takeoff was

 14.4--I ran the number before we departed because I knew the CG was

 "aft-ish"--and the weight was 2614 lbs.  Years ago during phase 1 we

 loaded the plane at aft CG, max gross, and did some stalls.  I don't

 recall anything strange at all about those maneuvers.

 

 First, I demonstrated an approach stall, which I've done many times.

 My normal recovery is just to add a little power, stick neutral if

 necessary, and the plane just flys out.  On the first stall, that's

 just how it went.

 

 Of course then it was time for a little "Watch this!"...

 

 Actually, I wanted to demonstrate the AOA audio warning,

 "Angle-Angle-Push", which was kind of faint on the first stall.  So I

 let the stall develop further, keeping wings level with the rudder.

 The wings rocked a bit but nothing serious.  The nose stayed straight

 ahead.  Then, the nose pitched WAY down.  I added power to break the

 stall and fly it out but there was no change.  It felt like we were

 descending, not flying. It felt like we were about 45* nose down, but

 the EFIS logs didn't capture anything that extreme.  I was concerned

 about entering a spin.  So was the guy in the front seat--he said so

 as it was happening...I added more power, stick neutral, and still the

 nose was pointed down.  I kept the wings more or less level but at

 this point things seemed out of the ordinary so I got more agressive

 with the controls.  I pushed forward, adding more power.  The plane

 then seemed to fly, and I seemed to be going pretty fast, but I didn't

 look at the airspeed.  I pulled up gently and the controls eventually

 started feeling normal again.  The EFIS logs showed the whole event

 lasted less than 10 seconds--two data captures--but it sure seemed

 longer.  We lost about 300 feet.

 

 I spoke to another -10 owner who has a lot of acro and formation

 experience.  He said, yeah, it'll do that...he concurred that from a

 deep stall, an RV-10 requires extra effort to break it.  That's

 probably not a huge surprise if you think about it and expect it, but

 in this case it gave me (and unfortunately my passengers) a little

 concern.

 

 I'd be interested to hear if others have had similar experiences, and

 if anyone has an explanation for what's going on aerodynamically.

 

 Dave Saylor

 831-750-0284 CL

dave.saylor.aircrafters(a
Guest

Posted: Sat Mar 02, 2013 9:58 am Post subject: RV-10 Stall Characteristics (what just happened here?)

Well, I didn't mean to make it seem super dangerous...it wasn't like I

was seeing scenes from my childhood or anything.  It got my attention

and it may have resolved itself after a few more seconds--I don't

know.  I didn't feel terribly out of control or anything but the plane

didn't respond exactly like I expected it too.  Unless I hear a reason

not to, I'm gonna try it again, but this time expect a slower

recovery.



Dave Saylor

831-750-0284 CL

On Sat, Mar 2, 2013 at 9:48 AM, John Jessen <n212pj(at)gmail.com> wrote:

 	  Quote: 	
		   



 Nice job getting out of that situation, Dave. Glad you are still with us!



 John J



 On Mar 2, 2013, at 9:35 AM, Dave Saylor <dave.saylor.aircrafters(at)gmail.com> wrote:



> 

>

> Last weekend I took some folks on demo rides.  All are -10 builders,

> not yet flying.

>

> On one flight, I had one big guy in the back seat.  My CG range is 8.4

> to 16.8 (inches aft of the wing leading edge).  My CG on takeoff was

> 14.4--I ran the number before we departed because I knew the CG was

> "aft-ish"--and the weight was 2614 lbs.  Years ago during phase 1 we

> loaded the plane at aft CG, max gross, and did some stalls.  I don't

> recall anything strange at all about those maneuvers.

>

> First, I demonstrated an approach stall, which I've done many times.

> My normal recovery is just to add a little power, stick neutral if

> necessary, and the plane just flys out.  On the first stall, that's

> just how it went.

>

> Of course then it was time for a little "Watch this!"...

>

> Actually, I wanted to demonstrate the AOA audio warning,

> "Angle-Angle-Push", which was kind of faint on the first stall.  So I

> let the stall develop further, keeping wings level with the rudder.

> The wings rocked a bit but nothing serious.  The nose stayed straight

> ahead.  Then, the nose pitched WAY down.  I added power to break the

> stall and fly it out but there was no change.  It felt like we were

> descending, not flying. It felt like we were about 45* nose down, but

> the EFIS logs didn't capture anything that extreme.  I was concerned

> about entering a spin.  So was the guy in the front seat--he said so

> as it was happening...I added more power, stick neutral, and still the

> nose was pointed down.  I kept the wings more or less level but at

> this point things seemed out of the ordinary so I got more agressive

> with the controls.  I pushed forward, adding more power.  The plane

> then seemed to fly, and I seemed to be going pretty fast, but I didn't

> look at the airspeed.  I pulled up gently and the controls eventually

> started feeling normal again.  The EFIS logs showed the whole event

> lasted less than 10 seconds--two data captures--but it sure seemed

> longer.  We lost about 300 feet.

>

> I spoke to another -10 owner who has a lot of acro and formation

> experience.  He said, yeah, it'll do that...he concurred that from a

> deep stall, an RV-10 requires extra effort to break it.  That's

> probably not a huge surprise if you think about it and expect it, but

> in this case it gave me (and unfortunately my passengers) a little

> concern.

>

> I'd be interested to hear if others have had similar experiences, and

> if anyone has an explanation for what's going on aerodynamically.

>

> Dave Saylor

> 831-750-0284 CL

>

>

Tim Olson

Joined: 25 Jan 2007
Posts: 2878

Posted: Sat Mar 02, 2013 10:03 am Post subject: RV-10 Stall Characteristics (what just happened here?)

I've seen something odd like this once too.  The situation was a bit

different though from the sounds of it.  Would you say that the

elevator felt somewhat aerodynamically "disconnected" during this?

The experience I had, you could hear the prop pitch change as it

sounded like it quit biting the air the same, and the pitch force

got real "sloppy", like you could have pulled or pushed and not

gotten a lot of response at all.  But, going into standard stall

recovery mode automatically, I shoved the stick forward and

it came right out of it.  The whole thing lasted only maybe 2 seconds,

but when you feel something like that you know how time goes slowly.

At any rate, I think I was just so deep in the stall at the time

that probably the wing wash interrupted the flow over the horizontal

stabilizer, or something like that.  So the elevator lost some

effectiveness.  At least that's what I attributed it to.

It wasn't quite a normal flight situation for me, so I've been

thinking of some day trying to recreate it up high, but I'm not

sure if I could, without the added weight of filled seats...so

I'm not sure if I'll bother.  The airplane behaved pretty well

through it, so I was happy for that.



Tim

On 3/2/2013 11:35 AM, Dave Saylor wrote:

 	  Quote: 	
		   



 Last weekend I took some folks on demo rides.  All are -10 builders,

 not yet flying.



 On one flight, I had one big guy in the back seat.  My CG range is 8.4

 to 16.8 (inches aft of the wing leading edge).  My CG on takeoff was

 14.4--I ran the number before we departed because I knew the CG was

 "aft-ish"--and the weight was 2614 lbs.  Years ago during phase 1 we

 loaded the plane at aft CG, max gross, and did some stalls.  I don't

 recall anything strange at all about those maneuvers.



 First, I demonstrated an approach stall, which I've done many times.

 My normal recovery is just to add a little power, stick neutral if

 necessary, and the plane just flys out.  On the first stall, that's

 just how it went.



 Of course then it was time for a little "Watch this!"...



 Actually, I wanted to demonstrate the AOA audio warning,

 "Angle-Angle-Push", which was kind of faint on the first stall.  So I

 let the stall develop further, keeping wings level with the rudder.

 The wings rocked a bit but nothing serious.  The nose stayed straight

 ahead.  Then, the nose pitched WAY down.  I added power to break the

 stall and fly it out but there was no change.  It felt like we were

 descending, not flying. It felt like we were about 45* nose down, but

 the EFIS logs didn't capture anything that extreme.  I was concerned

 about entering a spin.  So was the guy in the front seat--he said so

 as it was happening...I added more power, stick neutral, and still the

 nose was pointed down.  I kept the wings more or less level but at

 this point things seemed out of the ordinary so I got more agressive

 with the controls.  I pushed forward, adding more power.  The plane

 then seemed to fly, and I seemed to be going pretty fast, but I didn't

 look at the airspeed.  I pulled up gently and the controls eventually

 started feeling normal again.  The EFIS logs showed the whole event

 lasted less than 10 seconds--two data captures--but it sure seemed

 longer.  We lost about 300 feet.



 I spoke to another -10 owner who has a lot of acro and formation

 experience.  He said, yeah, it'll do that...he concurred that from a

 deep stall, an RV-10 requires extra effort to break it.  That's

 probably not a huge surprise if you think about it and expect it, but

 in this case it gave me (and unfortunately my passengers) a little

 concern.



 I'd be interested to hear if others have had similar experiences, and

 if anyone has an explanation for what's going on aerodynamically.



 Dave Saylor

 831-750-0284 CL

Strasnuts

Joined: 10 Feb 2009
Posts: 502
Location: Salt Lake City, UT

Posted: Sat Mar 02, 2013 10:53 am Post subject: RV-10 Stall Characteristics (what just happened here?)

I was up experimenting with the stall in my 10. Mine is at the fwd cg with me alone so keep that in mind. I stalled and kept the stick full aft. The plane just buffeted and still had good aileron control. I stomped on the rudder both directions with full aft stick and the plane just mushed along. It would not enter a spin. Like I said I am close to the fwd CG.    I have a video of this I'll try to post later. 



Sent from my iPhone



On Mar 2, 2013, at 10:02, Tim Olson <Tim(at)MyRV10.com> wrote:



 	  Quote: 	
		   

 

 I've seen something odd like this once too.  The situation was a bit

 different though from the sounds of it.  Would you say that the

 elevator felt somewhat aerodynamically "disconnected" during this?

 The experience I had, you could hear the prop pitch change as it

 sounded like it quit biting the air the same, and the pitch force

 got real "sloppy", like you could have pulled or pushed and not

 gotten a lot of response at all.  But, going into standard stall

 recovery mode automatically, I shoved the stick forward and

 it came right out of it.  The whole thing lasted only maybe 2 seconds,

 but when you feel something like that you know how time goes slowly.

 At any rate, I think I was just so deep in the stall at the time

 that probably the wing wash interrupted the flow over the horizontal

 stabilizer, or something like that.  So the elevator lost some

 effectiveness.  At least that's what I attributed it to.

 It wasn't quite a normal flight situation for me, so I've been

 thinking of some day trying to recreate it up high, but I'm not

 sure if I could, without the added weight of filled seats...so

 I'm not sure if I'll bother.  The airplane behaved pretty well

 through it, so I was happy for that.

 

 Tim

 

 

 On 3/2/2013 11:35 AM, Dave Saylor wrote:

> 

> 

> Last weekend I took some folks on demo rides.  All are -10 builders,

> not yet flying.

> 

> On one flight, I had one big guy in the back seat.  My CG range is 8.4

> to 16.8 (inches aft of the wing leading edge).  My CG on takeoff was

> 14.4--I ran the number before we departed because I knew the CG was

> "aft-ish"--and the weight was 2614 lbs.  Years ago during phase 1 we

> loaded the plane at aft CG, max gross, and did some stalls.  I don't

> recall anything strange at all about those maneuvers.

> 

> First, I demonstrated an approach stall, which I've done many times.

> My normal recovery is just to add a little power, stick neutral if

> necessary, and the plane just flys out.  On the first stall, that's

> just how it went.

> 

> Of course then it was time for a little "Watch this!"...

> 

> Actually, I wanted to demonstrate the AOA audio warning,

> "Angle-Angle-Push", which was kind of faint on the first stall.  So I

> let the stall develop further, keeping wings level with the rudder.

> The wings rocked a bit but nothing serious.  The nose stayed straight

> ahead.  Then, the nose pitched WAY down.  I added power to break the

> stall and fly it out but there was no change.  It felt like we were

> descending, not flying. It felt like we were about 45* nose down, but

> the EFIS logs didn't capture anything that extreme.  I was concerned

> about entering a spin.  So was the guy in the front seat--he said so

> as it was happening...I added more power, stick neutral, and still the

> nose was pointed down.  I kept the wings more or less level but at

> this point things seemed out of the ordinary so I got more agressive

> with the controls.  I pushed forward, adding more power.  The plane

> then seemed to fly, and I seemed to be going pretty fast, but I didn't

> look at the airspeed.  I pulled up gently and the controls eventually

> started feeling normal again.  The EFIS logs showed the whole event

> lasted less than 10 seconds--two data captures--but it sure seemed

> longer.  We lost about 300 feet.

> 

> I spoke to another -10 owner who has a lot of acro and formation

> experience.  He said, yeah, it'll do that...he concurred that from a

> deep stall, an RV-10 requires extra effort to break it.  That's

> probably not a huge surprise if you think about it and expect it, but

> in this case it gave me (and unfortunately my passengers) a little

> concern.

> 

> I'd be interested to hear if others have had similar experiences, and

> if anyone has an explanation for what's going on aerodynamically.

> 

> Dave Saylor

> 831-750-0284 CL

_________________
40936
RV-10 SB N801VR Flying
780 Hours
SuperSTOL 60 hours

stein(at)steinair.com
Guest

Posted: Sat Mar 02, 2013 11:23 am Post subject: RV-10 Stall Characteristics (what just happened here?)

Sounds good! I'll pencil it in.



Cheers,



Stein Bruch

President - SteinAir, Inc.

651-460-6955



--

Tim Olson

Joined: 25 Jan 2007
Posts: 2878

Posted: Sat Mar 02, 2013 11:24 am Post subject: RV-10 Stall Characteristics (what just happened here?)

I think the CG has a lot of difference in how it behaves.

This flight I was way lighter in back and I could hold

the stick almost all the way back and not get it to do

anything funky.  I added a video to this page today

just for kicks.



http://www.myrv10.com/N104CD/flights/20080414/index.html

Tim Olson - RV-10 N104CD

do not archive

On 3/2/2013 12:34 PM, Seano wrote:

 	  Quote: 	
		   



 I was up experimenting with the stall in my 10. Mine is at the fwd cg

 with me alone so keep that in mind. I stalled and kept the stick full

 aft. The plane just buffeted and still had good aileron control. I

 stomped on the rudder both directions with full aft stick and the

 plane just mushed along. It would not enter a spin. Like I said I am

 close to the fwd CG.    I have a video of this I'll try to post

 later.



 Sent from my iPhone



 On Mar 2, 2013, at 10:02, Tim Olson <Tim(at)MyRV10.com> wrote:



> 

>

> I've seen something odd like this once too.  The situation was a

> bit different though from the sounds of it.  Would you say that

> the elevator felt somewhat aerodynamically "disconnected" during

> this? The experience I had, you could hear the prop pitch change as

> it sounded like it quit biting the air the same, and the pitch

> force got real "sloppy", like you could have pulled or pushed and

> not gotten a lot of response at all.  But, going into standard

> stall recovery mode automatically, I shoved the stick forward and

> it came right out of it.  The whole thing lasted only maybe 2

> seconds, but when you feel something like that you know how time

> goes slowly. At any rate, I think I was just so deep in the stall

> at the time that probably the wing wash interrupted the flow over

> the horizontal stabilizer, or something like that.  So the elevator

> lost some effectiveness.  At least that's what I attributed it to.

> It wasn't quite a normal flight situation for me, so I've been

> thinking of some day trying to recreate it up high, but I'm not

> sure if I could, without the added weight of filled seats...so I'm

> not sure if I'll bother.  The airplane behaved pretty well through

> it, so I was happy for that.

>

> Tim

> On 3/2/2013 11:35 AM, Dave Saylor wrote:

>> 

>> <dave.saylor.aircrafters(at)gmail.com>

>>

>> Last weekend I took some folks on demo rides.  All are -10

>> builders, not yet flying.

>>

>> On one flight, I had one big guy in the back seat.  My CG range

>> is 8.4 to 16.8 (inches aft of the wing leading edge).  My CG on

>> takeoff was 14.4--I ran the number before we departed because I

>> knew the CG was "aft-ish"--and the weight was 2614 lbs.  Years

>> ago during phase 1 we loaded the plane at aft CG, max gross, and

>> did some stalls.  I don't recall anything strange at all about

>> those maneuvers.

>>

>> First, I demonstrated an approach stall, which I've done many

>> times. My normal recovery is just to add a little power, stick

>> neutral if necessary, and the plane just flys out.  On the first

>> stall, that's just how it went.

>>

>> Of course then it was time for a little "Watch this!"...

>>

>> Actually, I wanted to demonstrate the AOA audio warning,

>> "Angle-Angle-Push", which was kind of faint on the first stall.

>> So I let the stall develop further, keeping wings level with the

>> rudder. The wings rocked a bit but nothing serious.  The nose

>> stayed straight ahead.  Then, the nose pitched WAY down.  I added

>> power to break the stall and fly it out but there was no change.

>> It felt like we were descending, not flying. It felt like we were

>> about 45* nose down, but the EFIS logs didn't capture anything

>> that extreme.  I was concerned about entering a spin.  So was the

>> guy in the front seat--he said so as it was happening...I added

>> more power, stick neutral, and still the nose was pointed down.

>> I kept the wings more or less level but at this point things

>> seemed out of the ordinary so I got more agressive with the

>> controls.  I pushed forward, adding more power.  The plane then

>> seemed to fly, and I seemed to be going pretty fast, but I

>> didn't look at the airspeed.  I pulled up gently and the controls

>> eventually started feeling normal again.  The EFIS logs showed

>> the whole event lasted less than 10 seconds--two data

>> captures--but it sure seemed longer.  We lost about 300 feet.

>>

>> I spoke to another -10 owner who has a lot of acro and formation

>> experience.  He said, yeah, it'll do that...he concurred that

>> from a deep stall, an RV-10 requires extra effort to break it.

>> That's probably not a huge surprise if you think about it and

>> expect it, but in this case it gave me (and unfortunately my

>> passengers) a little concern.

>>

>> I'd be interested to hear if others have had similar experiences,

>> and if anyone has an explanation for what's going on

>> aerodynamically.

>>

>> Dave Saylor 831-750-0284 CL

>

>

Bob Turner

Joined: 03 Jan 2009
Posts: 885
Location: Castro Valley, CA

Posted: Sat Mar 02, 2013 12:18 pm Post subject: Re: RV-10 Stall Characteristics (what just happened here?)

There's a huge difference between forward and aft cg's. Near the forward limit mine just mushes, it won't really stall. Aft limit is another story, although I've always found the stalls to be conventional.



I wonder about the "stick neutral"  business. Most aircraft call for some forward stick, for prompt stall recovery. You want to lower the angle of attack as quickly as possible. At low speeds it takes a pretty good control deflection to make the plane respond quickly. From a stall starting from a steep power on climb attitude, and aft cg, I definitely need some forward stick to un-stall promptly.



How long were you flying? As I'm sure you know, if you start with cg near the aft limit, it will move further aft as you burn gas. (Also true that if you start near the forward limit, cg moves forward as you burn gas.)

_________________
Bob Turner
RV-10 QB

dave.saylor.aircrafters(a
Guest

Posted: Sat Mar 02, 2013 12:38 pm Post subject: RV-10 Stall Characteristics (what just happened here?)

 	  Quote: 	
		  Would you say that the

 elevator felt somewhat aerodynamically "disconnected" during this?


	


Yep, that's how it felt.  No result from pushing the stick further and

further forward.



 	  Quote: 	
		   you could hear the prop pitch change as it sounded like it quit biting the air


	


I felt that too.  I added more and more power without the results I

expected.  Usually, adding power gives an immediate result but not in

this case.



The plane didn't "snap out" like it usually does, where you feel a

clear difference between stalled vs. flying.  It just felt less and

less stalled, at some point it felt normal, but not a really clear

line.



Which is very different from virtually every other mode of flight.

Everywhere else the plane just feels solid and predictable.  I've told

lots of people that it just doesn't have any bad habits.  Not that I'd

call this dangerous but it's good for people to be aware that some

behavior isn't perfectly linear.



I thought about this some more and so going back to Airplane 101, I'd

expect the nose to pitch down if the Hstab quits flying.  Isn't that

why we have a (conservative) aft CG limit, to make sure the nose falls

first in a "freefall situation?  Imagine if the tail dropped...yikes.

dave.saylor.aircrafters(a
Guest

Posted: Sat Mar 02, 2013 12:44 pm Post subject: RV-10 Stall Characteristics (what just happened here?)

Sean, that sounds pretty normal.  I've seen that too, where if you

slow down gently and just ease the stick to the stop, it sort of just

mushes along and you can steer around with the rudder.  If you give

the stick a sharp pull for the last couple inches you might get it to

break.  That's what I'd call a normal RV-10 stall.  Very gentle and

relaxed.



Dave Saylor

831-750-0284 CL

On Sat, Mar 2, 2013 at 10:34 AM, Seano <sean(at)braunandco.com> wrote:

 	  Quote: 	
		   



 I was up experimenting with the stall in my 10. Mine is at the fwd cg with me alone so keep that in mind. I stalled and kept the stick full aft. The plane just buffeted and still had good aileron control. I stomped on the rudder both directions with full aft stick and the plane just mushed along. It would not enter a spin. Like I said I am close to the fwd CG.    I have a video of this I'll try to post later.



 Sent from my iPhone



 On Mar 2, 2013, at 10:02, Tim Olson <Tim(at)MyRV10.com> wrote:



> 

>

> I've seen something odd like this once too.  The situation was a bit

> different though from the sounds of it.  Would you say that the

> elevator felt somewhat aerodynamically "disconnected" during this?

> The experience I had, you could hear the prop pitch change as it

> sounded like it quit biting the air the same, and the pitch force

> got real "sloppy", like you could have pulled or pushed and not

> gotten a lot of response at all.  But, going into standard stall

> recovery mode automatically, I shoved the stick forward and

> it came right out of it.  The whole thing lasted only maybe 2 seconds,

> but when you feel something like that you know how time goes slowly.

> At any rate, I think I was just so deep in the stall at the time

> that probably the wing wash interrupted the flow over the horizontal

> stabilizer, or something like that.  So the elevator lost some

> effectiveness.  At least that's what I attributed it to.

> It wasn't quite a normal flight situation for me, so I've been

> thinking of some day trying to recreate it up high, but I'm not

> sure if I could, without the added weight of filled seats...so

> I'm not sure if I'll bother.  The airplane behaved pretty well

> through it, so I was happy for that.

>

> Tim

> On 3/2/2013 11:35 AM, Dave Saylor wrote:

>> 

>>

>> Last weekend I took some folks on demo rides.  All are -10 builders,

>> not yet flying.

>>

>> On one flight, I had one big guy in the back seat.  My CG range is 8.4

>> to 16.8 (inches aft of the wing leading edge).  My CG on takeoff was

>> 14.4--I ran the number before we departed because I knew the CG was

>> "aft-ish"--and the weight was 2614 lbs.  Years ago during phase 1 we

>> loaded the plane at aft CG, max gross, and did some stalls.  I don't

>> recall anything strange at all about those maneuvers.

>>

>> First, I demonstrated an approach stall, which I've done many times.

>> My normal recovery is just to add a little power, stick neutral if

>> necessary, and the plane just flys out.  On the first stall, that's

>> just how it went.

>>

>> Of course then it was time for a little "Watch this!"...

>>

>> Actually, I wanted to demonstrate the AOA audio warning,

>> "Angle-Angle-Push", which was kind of faint on the first stall.  So I

>> let the stall develop further, keeping wings level with the rudder.

>> The wings rocked a bit but nothing serious.  The nose stayed straight

>> ahead.  Then, the nose pitched WAY down.  I added power to break the

>> stall and fly it out but there was no change.  It felt like we were

>> descending, not flying. It felt like we were about 45* nose down, but

>> the EFIS logs didn't capture anything that extreme.  I was concerned

>> about entering a spin.  So was the guy in the front seat--he said so

>> as it was happening...I added more power, stick neutral, and still the

>> nose was pointed down.  I kept the wings more or less level but at

>> this point things seemed out of the ordinary so I got more agressive

>> with the controls.  I pushed forward, adding more power.  The plane

>> then seemed to fly, and I seemed to be going pretty fast, but I didn't

>> look at the airspeed.  I pulled up gently and the controls eventually

>> started feeling normal again.  The EFIS logs showed the whole event

>> lasted less than 10 seconds--two data captures--but it sure seemed

>> longer.  We lost about 300 feet.

>>

>> I spoke to another -10 owner who has a lot of acro and formation

>> experience.  He said, yeah, it'll do that...he concurred that from a

>> deep stall, an RV-10 requires extra effort to break it.  That's

>> probably not a huge surprise if you think about it and expect it, but

>> in this case it gave me (and unfortunately my passengers) a little

>> concern.

>>

>> I'd be interested to hear if others have had similar experiences, and

>> if anyone has an explanation for what's going on aerodynamically.

>>

>> Dave Saylor

>> 831-750-0284 CL

>

>

dave.saylor.aircrafters(a
Guest

Posted: Sat Mar 02, 2013 1:04 pm Post subject: RV-10 Stall Characteristics (what just happened here?)

Bob,



Yes, I could probably stand to move the stick forward faster,

especially with aft CG.



My basic philosophy until now has been to break the stall by adding

power if possible.  I figure that what I'm practicing is an approach

stall, on final or elsewhere in the pattern, close to the ground.  In

that case, I want to loose as little altitude as possible so it makes

sense to me to avoid very much forward stick.  That goes out the

window if it doesn't work, though, so I'm reevaluating what I've been

taught.



I wanted to stay in the stall long enough to hear the AOA through a

few cycles, so I was asking for it.  We'd only be flying a few

minutes.  CG probably hadn't changed much from takeoff.  And, I took

the rear passenger's word for it when I input his weight in the

calculator.  But he couldn't have been off by much.  It seemed

reasonable.  I was 2+ inches forward of the aft limit, so I didn't

examine the data with a microscope, but I did take the opportunity to

demo the W&B program before we departed.



Dave Saylor

831-750-0284 CL

On Sat, Mar 2, 2013 at 12:18 PM, Bob Turner <bobturner(at)alum.rpi.edu> wrote:

 	  Quote: 	
		   



 There's a huge difference between forward and aft cg's. Near the forward limit mine just mushes, it won't really stall. Aft limit is another story, although I've always found the stalls to be conventional.



 I wonder about the "stick neutral"  business. Most aircraft call for some forward stick, for prompt stall recovery. You want to lower the angle of attack as quickly as possible. At low speeds it takes a pretty good control deflection to make the plane respond quickly. From a stall starting from a steep power on climb attitude, and aft cg, I definitely need some forward stick to un-stall promptly.



 How long were you flying? As I'm sure you know, if you start with cg near the aft limit, it will move further aft as you burn gas. (Also true that if you start near the forward limit, cg moves forward as you burn gas.)



 --------

 Bob Turner

 RV-10 QB





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=395431#395431

Tim Olson

Joined: 25 Jan 2007
Posts: 2878

Posted: Sat Mar 02, 2013 1:06 pm Post subject: RV-10 Stall Characteristics (what just happened here?)

Dave, were your flaps Up when this happened?

Tim

On Mar 2, 2013, at 2:34 PM, Dave Saylor <dave.saylor.aircrafters(at)gmail.com> wrote:

 	  Quote: 	

> Would you say that the

> elevator felt somewhat aerodynamically "disconnected" during this?

 Yep, that's how it felt.  No result from pushing the stick further and

 further forward.

> you could hear the prop pitch change as it sounded like it quit biting the air

 I felt that too.  I added more and more power without the results I

 expected.  Usually, adding power gives an immediate result but not in

 this case.

 The plane didn't "snap out" like it usually does, where you feel a

 clear difference between stalled vs. flying.  It just felt less and

 less stalled, at some point it felt normal, but not a really clear

 line.

 Which is very different from virtually every other mode of flight.

 Everywhere else the plane just feels solid and predictable.  I've told

 lots of people that it just doesn't have any bad habits.  Not that I'd

 call this dangerous but it's good for people to be aware that some

 behavior isn't perfectly linear.

 I thought about this some more and so going back to Airplane 101, I'd

 expect the nose to pitch down if the Hstab quits flying.  Isn't that

 why we have a (conservative) aft CG limit, to make sure the nose falls

 first in a "freefall situation?  Imagine if the tail dropped...yikes.

Bob Turner

Joined: 03 Jan 2009
Posts: 885
Location: Castro Valley, CA

Posted: Sat Mar 02, 2013 2:21 pm Post subject: Re: RV-10 Stall Characteristics (what just happened here?)

I'd buy into Tim's theory - combination of low airspeed plus some blanking of the airflow by the wings could leave the elevators with little effectiveness until the rotation caused by the cg location (slower for aft cg) brought them back to normal. Prop noise change could be the inner part of the blade stalling at low forward speed.

Dave, I'll bet you already apply forward pressure, as well as power, to recover from an approach stall. If you didn't, the airspeed would decay even more due to the trim feeling the prop blast and "thinking" that it's going too fast. This is one of the hardest things to teach students, that an application of power on final approach requires forward stick pressure, to avoid a loss of airspeed (in most low tail airplanes). That being said, it's probably not a bad idea to practice stalls with power off and staying off, just in case you ever find yourself without power and trying to glide just a little more than is possible.

_________________
Bob Turner
RV-10 QB

dave.saylor.aircrafters(a
Guest

Posted: Sat Mar 02, 2013 7:00 pm Post subject: RV-10 Stall Characteristics (what just happened here?)

Yeah, flaps up.



Dave Saylor

831-750-0284 CL

On Sat, Mar 2, 2013 at 1:03 PM, Tim Olson <Tim(at)myrv10.com> wrote:

 	  Quote: 	
		   



 Dave, were your flaps Up when this happened?

 Tim

 On Mar 2, 2013, at 2:34 PM, Dave Saylor <dave.saylor.aircrafters(at)gmail.com> wrote:



> 

>

>> Would you say that the

>> elevator felt somewhat aerodynamically "disconnected" during this?

>

> Yep, that's how it felt.  No result from pushing the stick further and

> further forward.

>

>> you could hear the prop pitch change as it sounded like it quit biting the air

>

> I felt that too.  I added more and more power without the results I

> expected.  Usually, adding power gives an immediate result but not in

> this case.

>

> The plane didn't "snap out" like it usually does, where you feel a

> clear difference between stalled vs. flying.  It just felt less and

> less stalled, at some point it felt normal, but not a really clear

> line.

>

> Which is very different from virtually every other mode of flight.

> Everywhere else the plane just feels solid and predictable.  I've told

> lots of people that it just doesn't have any bad habits.  Not that I'd

> call this dangerous but it's good for people to be aware that some

> behavior isn't perfectly linear.

>

> I thought about this some more and so going back to Airplane 101, I'd

> expect the nose to pitch down if the Hstab quits flying.  Isn't that

> why we have a (conservative) aft CG limit, to make sure the nose falls

> first in a "freefall situation?  Imagine if the tail dropped...yikes.

>

Tim Olson

Joined: 25 Jan 2007
Posts: 2878

Posted: Sat Mar 02, 2013 8:05 pm Post subject: RV-10 Stall Characteristics (what just happened here?)

I think mine were too.  I've never had anything strange happen

when with full flaps.

Tim

On 3/2/2013 8:54 PM, Dave Saylor wrote:

 	  Quote: 	
		   



 Yeah, flaps up.



 Dave Saylor

 831-750-0284 CL

rv10flyer

Joined: 25 Aug 2009
Posts: 364

Posted: Sun Mar 03, 2013 7:29 am Post subject: Re: RV-10 Stall Characteristics (what just happened here?)

I practice full power, idle, flap and no flap stalls every few months with the family and xc trip loading at 3-5,000' AGL. This puts us at gross and my CG at 15.93" with full fuel. At the end of our 4.5 hr trip to Florida we were at 16.70", which made for a very touchy landing. I am pretty aggressive getting the stick very far forward on recovery and once flying nose low add power in slowly. I don't lose more than 200-300'. 



By myself and no flaps, I experience the same as you guys. Full aft stick with a little pitch rocking and plenty of pre-stall warning. Release pressure on stick and your flying again. Now with full flaps you don't get as much warning before the stall solo or gross. My stall buzzer goes off about 6 kts above stall. It is good for us to practice stalls often. My wife always calls my speeds on final using our D6 backup. Unless we are over the runway, she knows my min speeds of 70/75/80 KIAS(full, half, no flaps) as marked on the panel.

_________________
Wayne G.

woxofswa

Joined: 12 Aug 2008
Posts: 349
Location: AZ

Posted: Sun Mar 03, 2013 8:02 am Post subject: Re: RV-10 Stall Characteristics (what just happened here?)

I wouldn't discount the possible effects of air mass changes (wind).



A swirl, eddy, or gust at the wrong moment can create a defacto shear over the flying surfaces.  A 10 knot loss is normally no big deal, but a sudden loss of 10 knots of a wing approaching stall can have a huge effect on what that wing or tail feels at that precise moment and can affect the recovery.  The slower the aircraft the more pronounced the effect will be.  That is one way identical maneuvers can have different results. 



Think of a child's kite that flies steady then seemingly takes a plunge for no reason. 



Even in 150k lb aircraft, we add the gust factor of the winds to the approach target speed up to Vref +20

_________________
Myron Nelson
Mesa, AZ
Flew May 10 2014

flying-nut(at)cfl.rr.com
Guest

Posted: Sun Mar 03, 2013 8:56 am Post subject: RV-10 Stall Characteristics (what just happened here?)

Been following this thread .... not flying yet so this may be way out in 

left field.

I wonder if the RV-10 at gross and slow ends up behind the power curve???

Linn ..... hoping to find out some day ....

dave.saylor.aircrafters(a
Guest

Posted: Sun Mar 03, 2013 9:36 am Post subject: RV-10 Stall Characteristics (what just happened here?)

Thanks Wayne.  I think what I did differently was to let the stall

develop, thinking it would act about like it does at lighter

weights/fwd CG.  I wanted to demonstrate mushing along "sort of

stalled" but it showed me "very stalled" instead.



Dave Saylor

831-750-0284 CL

On Sun, Mar 3, 2013 at 7:29 AM, rv10flyer <wayne.gillispie(at)gmail.com> wrote:

 	  Quote: 	
		   



 I practice full power, idle, flap and no flap stalls every few months with the family and xc trip loading at 3-5,000' AGL. This puts us at gross and my CG at 15.93" with full fuel. At the end of our 4.5 hr trip to Florida we were at 16.70", which made for a very touchy landing. I am pretty aggressive getting the stick very far forward on recovery and once flying nose low add power in slowly. I don't lose more than 200-300'.



 By myself and no flaps, I experience the same as you guys. Full aft stick with a little pitch rocking and plenty of pre-stall warning. Release pressure on stick and your flying again. Now with full flaps you don't get as much warning before the stall solo or gross. My stall buzzer goes off about 6 kts above stall. It is good for us to practice stalls often. My wife always calls my speeds on final using our D6 backup. Unless we are over the runway, she knows my min speeds of 70/75/80 KIAS(full, half, no flaps) as marked on the panel.



 --------

 Wayne G.

 SB 12/01/2009-12/01/2011

 TT= 97.6





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=395494#395494

dave.saylor.aircrafters(a
Guest

Posted: Sun Mar 03, 2013 9:40 am Post subject: RV-10 Stall Characteristics (what just happened here?)

Good point.  That could certainly be a contributing factor.  The wind

at the airport was kind of weird that day.  We were landing on a

runway that we only use about twice a year, and it was gusty.



Dave Saylor

831-750-0284 CL

On Sun, Mar 3, 2013 at 8:02 AM, woxofswa <woxof(at)aol.com> wrote:

 	  Quote: 	
		   



 I wouldn't discount the possible effects of air mass changes (wind).



 A swirl, eddy, or gust at the wrong moment can create a defacto shear over the flying surfaces.  A 10 knot loss is normally no big deal, but a sudden loss of 10 knots of a wing approaching stall can have a huge effect on what that wing or tail feels at that precise moment and can affect the recovery.  The slower the aircraft the more pronounced the effect will be.  That is one way identical maneuvers can have different results.



 Think of a child's kite that flies steady then seemingly takes a plunge for no reason.



 Even in 150k lb aircraft, we add the gust factor of the winds to the approach target speed up to Vref +20



 --------

 Myron Nelson

 Mesa, AZ

 Emp completed, QB wings completed, legacy build fuse on gear.  Finishing kit and FWF kit in progress.





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=395501#395501

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