Loops with AeroVee

[mike.smith]

Does anyone have any tips to offer for good loops with an AeroVee? When I was doing loops during flight testing I seemed to be doing OK, but now I just keep stalling at the top; literally stalling the wing so a wing drops suddenly at the top, and I end up doing a lousy half Cuban eight. So I'm pretty sure I'm pulling too hard and exceeding the critical angle of attack. I'm starting by angling down to just over 120 kts. I have a G-meter, but I really can't be looking at it during the maneuver.

Thanks,

[mike.smith]

Is nobody doing aerobatics with their AeroVee Sonex? Aileron rolls are easy, stalls are easy to start and stop quickly, steep turns are a hoot. I know loops work, if I can figure out how to do them right, again :-) Go fast and pull hard doesn't seem to be doing the trick.

[Bryan Cotton]

Mike,
I have not started loops yet as I am missing a few things like wings etc. Also it has been a long time since my 10 hrs in the pitts but the first thing that came to mind was the top. Are you at low G on top or still pulling hard? The less G/pull you have will keep you further from stall. To keep the loop round you have to let up. As long as you are slightly positive the oil and fuel should stay where it needs to be.

[rizzz]

I've just done my second aerobatic session in my VW powered Sonex this morning, one the first one I nearly dropped out of the loops as well, just look at the video I posted last week in my Sonex #145 thread. Look at the airspeed at the top, I'm very close to 40KT at that point. Following the advise from another Aussie builder, this time around I used a bit more speed, just under 130KT, and pulled slightly less hard, about 3G. Worked much better, I'll upload a video shortly as I also did my first spins this morning.

[mike.smith]

I've just done my second aerobatic session in my VW powered Sonex this morning, one the first one I nearly dropped out of the loops as well, just look at the video I posted last week in my Sonex #145 thread. Look at the airspeed at the top, I'm very close to 40KT at that point. Following the advise from another Aussie builder, this time around I used a bit more speed, just under 130KT, and pulled slightly less hard, about 3G. Worked much better, I'll upload a video shortly as I also did my first spins this morning.

I'll have a look at the video. Thanks for the input :-)

The good thing about stalling my loops was that the first time I nearly ***t my pants! But after that it was just annoying that I wasn't getting it right, and it was just something to analyze.

[fastj22]

My first loop attempts in my Jab3300 waiex, I dropped out at the top of the loop entering an inverted spin. The plane recovered wonderfully. Glad I had some unusual attitude training before hand. Aileron rolls and barrel rolls are super easy. Spins are just too much fun. But good loops require some energy management.

[dhogue]

Try working your way down to good entry level speeds. ie 140 138 136 ect.

Start at 140, momentary straight and level.

Pull, say 2 or 3 G: Pick one then adjust as needed using the 140 entry speed.

As the horizon disappears below the top of the cowl - shift your view to one of the wing tips and use rudder to keep the horizon at the same Fore/Aft point on each wing tip (to keep the roll angle level).

As the aircraft slows on the vertical up half you may need to increase the pull, slightly, to keep the front side of the loop round.

As you approach the top of the loop, roughly 20 degrees before the top of the loop - shift your view straight ahead and slightly up to capture the inverted horizon as it is coming to view.
Then:
Release just enough of the back pressure to unload some of the G while transitioning inverted over the top from the climbing front side of the loop to the descending back half.

The above may help in not arriving at the top of the loop with too little airspeed to fly over the top, too much G and wing roll angle.

Repeat the above varying the entry speed and initial pull till you find what works.

I have not flown a Sonex yet but the above loop entries work well in Robin Sport and Decathlon so speed and G will probably be different for you.

[Onex107]

Something to consider when doing aerobatics. A standard Aerovee installation is not configured for negative G's. The way mine is installed, "0" or negative "G's" could result in fuel discharging from the tank vent and reduced or no pickup for the oil pump. Depending on how you have the crankcase vented, you could loose oil from the vent overboard. The engine will run a few minutes without oil pressure but I don't like the idea of gasoline spraying from the tank vent with the engine at full throttle.

[mike.smith]

Something to consider when doing aerobatics. A standard Aerovee installation is not configured for negative G's. The way mine is installed, "0" or negative "G's" could result in fuel discharging from the tank vent and reduced or no pickup for the oil pump. Depending on how you have the crankcase vented, you could loose oil from the vent overboard. The engine will run a few minutes without oil pressure but I don't like the idea of gasoline spraying from the tank vent with the engine at full throttle.

My fuel and oil vents are at the bottom of the cowl for just that reason. The aerobatics that most (all?) of us do in the Sonex are generally positive G maneuvers specifically because of the fuel and oil issues. But nobody is perfect, so occasionally we're going to go zero or negative G just because we muffed a maneuver. Momentary zero and negative G's are just a fact of life, and generally aren't going to create any issues (IMHO).