Flight Test, how close to spin?

[thinkn9a]

Ok,... I good with not doing a spin,... and looking at some videos,.. it is obvious some of our 6/7 brethern put on a pretty exciting ride (over and spin)

So,... how far how hard have folks pushed the 9/9A into stall/ cross control stall, and what are the recommnendations? How did you walk up to the line and look over without falling in?

Just wondering,.. one of these months I'm going to have to show my flight test plan, and would like to have some idea of what I will do out in that portion of testing.

tks

 

[frankh]

OK I'll get flamed for this!

I fly a 7a and LOve spins www.youtube.com/user/frankandmarci movie #9 I think gives you an idea.

I think if I were flying a 9 I would want to know what its spin recovery characteristics are..So I don't think I would do a fully developed spin but I might do an incipient spin entry..I.e a half to 1 turn spin and recover.

I think the loads on the airframe would be very light and I doubt it will spin very quickly.

FWIW..Flame suit firmly on

Frank

 

[thinkn9a]

It is not that I don't care to spin

I just don't care to go further than really is recommended.

I enjoyed several hops in my earlier military 'familirization" hops... and wan't too bad at altitude and direction of recovery,... of course then,... it was with canopy that slid and chute on my back. I have neither at this point, and did not install the canopy "quick" release.

Just trying to sort out from the Van's 'DON"T DO SPINS" to ok,.. what have folks done, and how was it.

 

[flyboy1963]

close to spins

My personal opinion is that coming close to a spin, is like trying to get almost pregnant!
FWIW, I've told this story before, but here it is again. I bought a well-built -9a last year, and was getting instruction from a many-thousand hour CFI /commmercial pilot, but not RV driver.
we were doing slow flight, power off stalls, part flap stalls, power on stall, so excuse me for an important configuration issue that I can't answer.
I think we were clean, power on, and the CFI was flying, we were lightly loaded, mid-c.g.
at the stall, he tried to 'hold it in the stall' partly to see if the rudder was effective in warding off the incipient spin. This was after a quicker stall entry that I did, where a wing started to drop, but I held it straight with rudder.
We were quite nose-high, and he kept pulling the stick back, while holding heading with rudder.
suddenly the plane pitched forward violently, about 2 g negative on the meter, the two of us hit the canopy ( gear was all secured), and we went past vertical, and began a dive that took almost 1000' to pull out of, at about 2.5 g (pulled power off of course)

What the heck was that? the RV pussycat stall? I guess we really are test pilots, and I resolved to practice stalls, but not to explore the 'deep stall' conditon further. I know many low-wings blank the tail when in a mushing stall, so control effectiveness is lost.

Now some guys will say that my plane is all out of rig, and I must have some inner ear problem, but let's just say this could be any average plane , on any average day, flown by any average pilot, and leave it at that for the purposes of education.

 

[N941WR]

Perry,

That is most interesting. I've done deep stalls with my -9 a number of times and never have I had it pitch over like you described. In fact, I have ridden my -9 down a few thousand feet using the rudder to keep the wings level. All w/o any strange thing happening like you describe. I guess each of our planes is unique.

 

[Roger Moore]

Spins

I have not spun anything but my old RV4, but have spun it regularly. The 4 enters a spin quite abruptly, much more so than the Pitts but it is very honest in the recovery. But I must add that if Vans says not to spin your model then DO NOT. Thats my 2 cents worth. Roger Moore

 

[flyboy1963]

Rv-007?

........well if James Bond hasn't the kahuna's to spin, then I certainly will NOT!

 

[AZtailwind]

Turbulence?

suddenly the plane pitched forward violently, about 2 g negative on the meter, the two of us hit the canopy ( gear was all secured), and we went past vertical, and began a dive that took almost 1000' to pull out of, at about 2.5 g (pulled power off of course)
What the heck was that? the RV pussycat stall?

Sound like you hit a rotor of turbulence while in the stall? maybe clear-air turbulence line? That is the only thing I can think of to explain that type of occurrence.
When I ran into that type of thing I was pinned to the top on the headliner in a fully loaded 182-a real eye opener-
But really-hitting any shear line would release all elevator authority while you where in the full stall- essentially allowing the nose to pitch over like yours did-

 

[snoop9erdog]

Too much forward push on the stick

A similar thing happened to me as I took a demo ride in the 9 @ LOE, but it was self inflicted. We went up and performed stalls and at the crest where the stall occurred, I pushed forward on the stick and we went over like you do in a roller coaster at Knotts Berry Farm. Had I gently relaxed the stick, I believe it would have been a non event. This is probably what happened if your non RV CFI was man handling the stick.

My .02

Ed

 

[kentb]

Perry, just to be clear

Where you in a bank, but using rudder to maintain your course?
In which case this would be cross controlled, ball not centered.

I have stall straight ahead with ball centered and can hold it there for as long as I want. I'll be dropping at more the 1000 ft per minute, but the wings will be level.
I have also stalled in a bank, but with the ball centered. The plane is flying a circle, but stalled the same without dropping a wing.

Kent

 

[akarmy]

So,... how far how hard have folks pushed the 9/9A into stall/ cross control stall, and what are the recommendations?

During my test phase here are some of the things I did and the results...

Normal stalls, normal recovery nothing new to report here.

Accelerated stalls in a 60deg bank, it would break and pitch out to level flight most of the time.

Stall with pro spin rudder added at the break, wing drops and the spin starts. I always recovered at less than 1/4 turn. In general it wants to roll over fairly steeply on the entry. Note to self, keep the ball centered.

Last thing on my test cards... cross controlled stalls. This was to simulate the base to final turn with a bit of wind and holding opposing rudder. Not something you should ever be doing, but I figured it would be good to know what happens... Climbed to 6000ft for this one, slowed down, left rudder, right aileron, keep slowing... (some of you are laughing by now)... wait for it. At the break, just a little bobble and bam snaps 180deg to inverted Recovery is to finish the roll back right side up. Notes on card, never do cross controlled stalls again!

 

[frankh]

Funny!

The one way to make an RV spin fast is to add opposite aileron....Pretty good for snap rolls too not surprisingly...

Don't try this in a 9/10...but the others..woohoo..

Frank

 

[carguy614]

Oh yeah...

Check my archived post on the result of cross control stalls. the 9 stall full cross controlled is violent and inverting. I managed to upright the craft, but I was ready for it. if it happened when you weren't ready, you WILL be upside down in a heartbeat. As previosly posted, best to roll it out. I am not sorry I explored this part of the 9's envelope, but it should be approached with caution, and at sufficent altitude. Regular old stalls are very predictable and gentile, and I have never experienced any sudden nose down pitching. I think maybe the stick was jabbed forward abruptly in the recovery, or turbulence might have been an issue. These birds will build speed at an amazing rate with the nose down. I did a few emergency descents with my 9A, and ended up with some serious airspeed on one of them. Flutter testing complete!!

Be careful!!

Chris

 

[Kevin Horton]

Check my archived post on the result of cross control stalls. the 9 stall full cross controlled is violent and inverting. I managed to upright the craft, but I was ready for it. if it happened when you weren't ready, you WILL be upside down in a heartbeat.

I wonder if you develop enough sideslip in this case so that the part of the HS that is in the lee of the VS stalls. With those big slotted flaps on the -9, there would be a lot of nose down pitching moment for the horizontal tail to fight against. If part of the HS were to stall, the result would be a sharp nose down pitch.