Lesson learned rv 7

While flying last weekend I was doing mild aerobatic maneuvers and in a wing level climbing move I pulled too hard and experienced a stall severe enough to hear an audible bang noise. Flew home and inspected the fuselage with no issues. Won't do that again but the strange part was it did not feel like I was pulling that hard but must have been.





Dues paid

I have one area of my aft fuselage that will "oil can" at times...

Yup, I second the oil canning!

I have an oil can bang that happens all the time when slowing down from downwind to base leg.

I am willing to bet that is the sound you heard.

CJ

G meter?

It's easy to load up the G's, and having the G meter will help tune your senses...it's the stuff the airframe suffers that doesn't make a bang you need to worry about. Visual inspections only tell part of the story. Be carefull!

Robb said:

While flying last weekend I was doing mild aerobatic maneuvers and in a wing level climbing move I pulled too hard and experienced a stall severe enough to hear an audible bang noise. Flew home and inspected the fuselage with no issues. Won't do that again but the strange part was it did not feel like I was pulling that hard but must have been.





Dues paid

Click to expand...

Check lower fuse skin two stations behind the baggage bulkhead. It is the first one without the fore-aft center rib.

Same on my 7A.... a pop sound that actually sounded like oil canning on downwind that use to get my attention the first few times. It must be a change in the airflow under the fuse. My guess is it's the aft bottom of the fuse taking on a more direct airflow as the nose comes up.

I think this was an accelerated stall from too much G force. I inspected the plane and found no visible damage but it was more than oil canning for sure.

'Bang' on accerated stall

I was out doing aerobatics with a friend in a T-34. Same airfoil by the way, known for harsh stall onset. I did a John Deary turn (roll 3/4 snap roll to the right to turn left) when I checked the roll and pulled to turn hard, I got the loudest BANG I've ever heard in an airplane. As if something hit it.
I guess its oil canning, but it sure got my attention.

Robb said:

I think this was an accelerated stall from too much G force. I inspected the plane and found no visible damage but it was more than oil canning for sure.

Click to expand...

Unless you saw 8 or 9 G's on the meter, I wouldn't worry about "too much G force". I'd bet you didn't even hit 5. An accelerated stall never hurt anything. Oil canning most likely as others have mentioned.

Let me add this.... In my earlier post above, I had given the oil canning theory my vote. With that said let me add this.... I do recall during my transition training with the guy down by Lake Okeechobee in Florida, sorry can't remember his name, he demonstrated a couple of accelerated stalls. Sitting here thinking about that experience I remember hearing a sound that I would probably describe like you did as a "bang" and definitely not the same oil can pop I frequently hear on downwind. I also recall that the bang sounded like it came from outside the aircraft very close to the cockpit... (wings?). I remember when it happened thinking I had never heard that sound before. So, you may be correct in your thinking and now I'm in agreement that it probably is what you heard.

thanks for the info guys i feel better now just didn't want to mess up the plane. its a whole different animal than my Husky

I would be careful doing acro without a G meter. I regularly pull +6G/-3 in my Pitts and can tell about when I get those numbers.... But the first time I looped an RV6 the G load increased MUCH faster than I thought it would. I was planning for a 3.5G loop and got a 5G loop.

It is just very hard to have a calibrated *** unless you know the plane and have have calibrated your butt in that plane. It is a factor of knowing entry speed, maneuver, pull force, speed at various points.... I don't think I could just hop in a strange plane and trust my "feel" to not over stress it... I know I could not in the RV, it has a very powerful elevator.

Canopy chatter

Occasionally during an aggressive spin entry or just wind up turns with an intentional accelerated stall, the canopies on the may have just enough play in the rollers / rails that they make a popping sound at the stall break. My 8 will do it some times if its a very aggressive stall break. I think the canopy is loaded in compression during most flight regimes, but when there is a sudden unloading, they might be moving just a bit. Another example of this is when I demo a power on stall in a 9A tip I fly, the canopy is nice and tight in flight, but hold it in a sustained buffet stall and the canopy will chatter against the latches. I mounted a go-pro on my 8 canopy during spin testing and it clearly showed a slight jump in the roller to rail junction during the break, even recorded the sound. Scared me silly until I figured out what it was. Did the same thing on a 6A during accelerate stall flight testing, but much more pronounced.
Your results and assumptions may vary from mine.

This might be a bit of drift and if so, sorry about that.

I my 7A, for a long time but once in a while I would hear a bang noise that sounded like a possible oil canning but rather louder and from inside and behind the cockpit but I could not pin point to where/what. This kept happening at times until I realized it was my plastic water bottle that would collapse due to different pressure and after descending from higher altitude to land. Rather silly but it kept me wondering and also a bit nervous that something is not right.