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-   -   Flight Testing (https://vansairforce.net/community/showthread.php?t=92947)

Bayou Bert 11-09-2012 04:27 AM

Flight Testing
 
As someone getting ready to start building an RV9A after the 1st, I have been reading throught the Van's build manual.
Van's has the flight testing in the back of the manual and reading it made the hair standup on my neck.
Does everyone push their new airplanes to the limits outlined in the manual?
Sure was a lot of parachute wearing needed.
One that really got my attentions was under Glide testing.
The manual has a statement in it about the danger of, too much or not enough rudder, and approach airspeed, causing the plane to snap over inverted! Are they talking about a stall to spin situation? They don't say spin but they say SNAP to inverted either forward or over.
Sure would like some comments on what everyone does in flight testing and about the comment on the snapping of the plane.

Bert:)

pierre smith 11-09-2012 04:59 AM

Hi Bert...don't fret over this stuff yet. Many airplanes, if not most, will snap over of you have a bad skidding situation when you stall, not just RV's. It's also what you do for intentional spin entry....full rudder and elevator.

Flying with a centered ball is good pilotage and what we should strive for, anyway. When you start flying your RV, you should have had transition training and you and the instructor can practise stalls with an increasing amount of rudder and explore gradually, the airplane's behaviour.

Best,

Bayou Bert 11-09-2012 06:07 AM

Thanks
 
Thanks Pierre, did some stalls in an RV10 last weekend getting started
on transition training with Alex De Dominics. All were ball centered but
I did hold on to one, just kept the stick back to see if if wanted to see
it if wanted to drop a wing. It stayed flat until I relaxed the stick and then
immediately flew. The buffet starts early with plenty of warning. I am told the RV9 does the same.
The manual didn't call it spin entry that's what caught my attention.
The other stuff, max G's, Vne and the other structure testing.
Does everyone push their new planes right to the limits?
Think that what's bothering me.

Bert:)

Mel 11-09-2012 06:17 AM

Every new airplane should be pushed near the limits. This is the only way to determine where the limits are.

It is STRONGLY recommended that this be done by an experienced test pilot.

No, in many cases, this is not done, but it really should be. Otherwise, how will you know the limits of the envelope?

Many people will argue that the RV line of aircraft are pretty much proven, but in reality, every airplane is different and should be treated as such.

Kahuna 11-09-2012 06:26 AM

What Mel said.

Having flight tested dozens of RV's and other aircraft, I can assure you that they do not all behave the same.

As noted, this early in your process, you need not fret about flight testing. There are other elephants in the room.

RV8R999 11-09-2012 06:50 AM

Agree with a caveat..

Some limits should not be explored without proper instrumentation and analysis such as structural limits. You cannot determine these limits without having a properly instrumented aircraft - structural instrumentation.

You can verify the designed envelop but not the limit without really putting yourself in jeopardy.

WAM120RV 11-09-2012 07:26 AM

Testing
 
In in the UK with an unknown design there is a rigorous flight testing procedure before an aeroplane is signed off for build on the LAA scheme.

With known types like RV's provided they are built to plans the 5 hours of testing is required, including one two hour flight and all round the envelope.

With our Wam engined RV we were required to do a minimum of 15 hours of light testing but I actually did more than that before I got it signed off.

Every year at permit renewal after airframe inspection we do a flight test.... rate of climb, stalls, clean and dirty, vne dive, baulked approaches and the like.

Aerobatic RV's have to be signed off individually and put fully through the aeorbatic envelope.

All of this is to ensure your safety, so you know where the limits are and can fly within them. So, as others have said to not get wound up about this it is a good thing..... if you don't feel competent to do it get someone who is and during transition training explore the envelope...... but don't pus beyond it.

:o

smiller 11-10-2012 12:48 PM

Yeah I think I would discourage testing to see how many g's your freshly-built plane can tolerate before a wing snaps off! If however you plan to routinely pull X g's, I'd want to test that (at altitude, solo, away from populated areas, with parachute, assuming you can free yourself from the out-of-control plane if something does snap!).

BobTurner 11-10-2012 05:02 PM

Most RVs have a predictable stall. But, you never know. You are a test pilot. You should feel comfortable with spin recovery if you are doing the testing.

flyboy1963 11-10-2012 08:31 PM

Flight test= test pilot?
 
Bert, if you're still reading this thread, a high-time commercial pilot was exploring the stall behaviour of my newly -purchased, well-built RV-9a.
I'm afraid I can't verify the exact configuration, but let's say you have to be ready for anything, and if you're not up to unusual attitude recoveries, not a bad idea to find someone who is.
He found a power-on, nose high stall resulted in some kind of tail blanking, or elevator stall that caused a sudden snap to vertical, straight ahead, nose down. Nothing like a windshield full of lake to get your attention, as you bang your headset on the canopy!
funny, that was the last time we intentionally did any stalls. Right or wrong, I don't think he would be of the opinion that Rv's have benign, mushing gentle stall behaviour....and it has given me a newfound respect for that regime.


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