C

Captain Avgas

Well Known Member
I flew a friend's RV6A recently so he could concentrate on inputting his Dynon AOA set-up parameters. One of the set-ups called for taking the aircraft to a power-off stall which I did. At the stall the aircraft had a sudden and attention grabbing left wing drop. I did this same maneouvre several times with the same result. In each case the left wing dropped severely at the stall with the stick full aft and the rudder neutral. Recovery was obtained with positive control inputs (stick to neutral, right rudder).

I mentioned this to another friend who flies an RV7 and he stated that his aircraft also drops the left wing at a power-off stall. He said he believed the left wing drop was normal in the RV....but I am not so sure of this.

I did a number of power-off stalls in a Vans RV6A when I did my transition training with Mike Seagar and there was no sudden left wing drop. If my memory serves me right (it was quite a few years ago) it was possible to keep the plane wings level in the stall with the stick full aft just by slight rudder inputs.

I am guessing therefore that my friend's planes may not be rigged to perfect tolerances.

I'd certainly like to know if other RV pilots out there think that a sudden left wing drop is normal at a power-off stall in an RV6 or RV7.
 
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more left rudder

me thinks, try adding a touch of power and stall, see what happens.

Randy
 
The prop is still spinning, right? Which way does the prop turn? Is the airplane rolling in the opposite direction when you stall?
 
RV's are sensitive to power levels and how much rudder you are inputing during the stall. I can make mine drop either wing or no wing depending on how I manipulate it. Try a full power on stall if you want some excitement but you might want to be current with your unusual attitude/upset training.
 
I have a -6A

...and at gross weight & full fuel, power off, prop windmilling @ 800rpm, stalls with a RIGHT WING drop. Not severe, but it does drop noticeably. To get to gross weight, I added weights in the passenger seat.

At 200 lbs under gross, the stall is with wings level. Wheel pants were not installed.

Now @ gross weight, wheel pants and fairings installed, power off, the stall is with a right wing drop, and although I would not call it severe, it is more pronounced than before.

With the wheel pants and fairings installed, I now have a heavy right wing in level flight. I am presently using the manual aileron trim to balance this out. I will be addressing the heavy wing on the next few flights, and then see if the stall characteristics change.

edit...Ball is always centered.
 
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Where is "the ball?"

Brantel said:
RV's are sensitive to power levels and how much rudder you are inputing during the stall. I can make mine drop either wing or no wing depending on how I manipulate it. Try a full power on stall if you want some excitement but you might want to be current with your unusual attitude/upset training.
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I agree with Brantel, my '8' will break either way by very slightly cross controlling. Normal airplane stuff.

John Clark ATP, CFI
FAA FAAST Team Member
EAA Flight Advisor
RV8 N18U "Sunshine"
KSBA
 
Interesting thread. My 6A stalls straight with flaps up, but with flaps down it rolls off to the left (ball centered, power off).
 
Left wing stall

Interestingly, my -9A stalls straight ahead while maintaing neutral ball at idle power. BUT... while carrying about 1200 rpm doing accellerated stalls, the left wing ALWAYS drops first, regardless of left or right turn in the stall. My assumption is that it's related to engine torque.
 
I suspect flap rigging can be an issue.
My 9A used to have a pronounced left wing drop in a full flap stall. Since then I tweaked the flap rigging using a home made wing top alignment tool rather than simply lining up the flap with the aileron. Stalls are now pretty much level with maybe a slight left wing drop with full flap depending on power and lateral weight distribution.

Fin
9A
 
rv9av8tr said:
Interestingly, my -9A stalls straight ahead while maintaing neutral ball at idle power. BUT... while carrying about 1200 rpm doing accellerated stalls, the left wing ALWAYS drops first, regardless of left or right turn in the stall. My assumption is that it's related to engine torque.
Click to expand...

That is my suspicion as well... if the prop turns clockwise as viewed from the cockpit, then the torque would drop the left wing in a stall... prop goes clockwise, wing goes counterclockwise (left wing down).
 
Brantel said:
Try a full power on stall if you want some excitement but you might want to be current with your unusual attitude/upset training.
Click to expand...

We were restricted to quite low altitude by airspace overhead so I wasn't game to tempt fate with a power-on stall. After the severe power-off wing drop I was inclined to think the power-on stall would be like a snap roll. :D

However during transition training I did power-on stalls with Mike Seagar in the Vans factory built RV6A and there was no pronounced wing drop either way. At the buffet it was just a matter of pushing the stick forward and flying away. I'm beginning to suspect it's all in the accuracy of the rigging.

John Clark said:
I agree with Brantel, my '8' will break either way by very slightly cross controlling. Normal airplane stuff.
John Clark
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I'm not certain that a break either way is "normal airplane stuff", certainly not for most certificated singles because most of them have geometric twist (washout) in their wings (eg Cessna, Piper) so they exhibit a degree of residual aileron control at the stall. It's very easy to keep a Cessna or Piper wings level at the stall. You have to be VERY ham fisted to get them to drop a wing.

But the RVs have "Hershey bar" :) wings with no twist so I suspect they're prone to a sudden wing drop one way or the other at the stall depending on the accuracy of the rigging. I guess the RVs are more on a knife edge.

Finley Atherton said:
I suspect flap rigging can be an issue.
Fin
9A
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Yes, flap rigging, and wing rigging, and gear fairing rigging etc. In their RV7 construction manual Vans claims that a 1/4" inaccuracy in a gear leg fairing can cause a half scale deflection in the skid ball :eek:

It obviously takes a lot of time, concentration, and technical finesse to get an RV rigged everywhere to high accuracy. My best guess is that many builders are not prepared to put in the time and effort required to get highly accurate alignments.... and a sudden and consistent one way wing drop at the stall is the end result.
 
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I too have a slight left wing drop in a power off stall. Power on is a little more neutral. Probably 5 or 10 degrees of drop is all. When you say "severe" how much bank are you talking about? I wonder if you do stalls in a right bank how it would perform?
 
Finley Atherton said:
I suspect flap rigging can be an issue.
My 9A used to have a pronounced left wing drop in a full flap stall. Since then I tweaked the flap rigging using a home made wing top alignment tool rather than simply lining up the flap with the aileron. Stalls are now pretty much level with maybe a slight left wing drop with full flap depending on power and lateral weight distribution.
Click to expand...

I had the same problem with the same fix. I have no wing drop for most configuraitons with a (coordinated) stall. With full flaps there is a very slight left wing drop.

RV-7A
 
apkp777 said:
When you say "severe" how much bank are you talking about?
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The wing continued to drop until corrective action was taken (released aft pressure on stick, a bit of right rudder). The break was quite sudden and the roll was so rapid that typically the aircraft was rolling to about 45 degrees before I could respond. It felt to me like the beginning of an incipient spin but at my low altitude I was not about to let it develop further to find out.
 
RV7A stall video

For those who haven't already seen it, here's a video shot by Mike Newall of his recently posted first flight in his RV7.

At 03:50 minutes Mike initiates a power-off stall and follows up directly thereafter with two power-on stalls. In every instance you can see the aircraft shudder at the onset of the stall. Well worth a look.

http://www.youtube.com/watch?v=R1izemwpDAY

It is relevant that there is NO wing drop, neither left or right, at either the power-off or power-on stalls. This is consistent with my experience in the Vans factory built RV6A that I flew for transition training with Mike Seagar.

I can only conclude from this that if an RV6(A) or RV7(A) drops a wing during a wings-level coordinated stall then it is not accurately rigged.

Does anybody agree...or disagree with that premise.
 
I agree.

If the airplane is rigged properly and the ball is kept centered, you should not drop a wing.
 
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