Spin, engine quit

[mike.smith]

Been doing acro with my AeroVee and AeroInjector for 9 years. Never had it quit. I've had it burp once doing a hammerhead when I got to 0 g's. I've done up to 5-turn spins. I've never reset my carb needle in 8.5 year. I've been lucky enough to have the AeroInjector be in the absolute sweet spot for all that time. I use the mixture all the time. So in the summer I NEVER push the carb to full rich. In fact, if I try to do that on take-off the engine will stumble. So I keep the mixture out about an inch in the summer. In the winter I push it to full rich for take-off, but lean after that. In the air I lean aggressively. I never reset the needle because of the climate or temperatures.

All of that is to say, if you get the AeroInjector dialed in to how you operate, it works like a champ. If you treat it like an OEM airplane engine, my experience is you are going to have issues. You have to see what works for you in your climate, and what you do with the airplane, set up the AeroInjector accordingly, and operate the engine within those parameters.

If the engine cut during a spin, my first guess would be the mixture/needle is too lean. I don't think I ever pull the throttle to "full" idle when I'm doing spins or any aerobatics. I've always got something in there, even if not a lot. Maybe that's something to try.

[Bryan Cotton]

Thanks Mike. I have not had another engine quit. I've had stumbles if I go a little negative on the roll. For my loop this morning it was happy. Split Ss were no problem. Hammerheads coming up soon.

I have been going all the way to idle downhill on the loop. I haven't done more spins but plan to leave some throttle in.

[Scott Todd]

I've owned 3 Aerovee's and flown two others. I currently have two flying including my new Onex. I have about 150 hours in all of them. ALL of them have been on the rich side. They definitely need leaned on taxi or will stumble on takeoff. Never had one quit but the stumble can be alarming if not ready for it. I always use 100 LL AvGas. I've only ever done 1 turn spins. I generally don't do Aerobatics and when I do, keep them to a minimum.

I follow everything Mike says. Done aerobatics in all of them and never had one quit. I tend to avoid 0g's and keep everything positive. I love the simplicity of the AeroInjector. It just work. Sure, it may not be efficient and it burns more fuel than the Rotax's, but I'm happy to give it a fresh oil change ever 20 hours or so and feed it as much 100LL as it wants with me usually flying it on the rich side. I'm one of those people that NEVER say a word about gas prices. I think the fuel price gets lost in the noise of all the other expenses associated with Aviation. You just can't beat 140mph at 4gph for the price.

Tune it a tad rich and it will not let you down :)

[mike.smith]

I've put a number of aerobatic flights on YouTube:

https://www.youtube.com/@mikesmith208/videos
https://www.youtube.com/watch?v=ctzIi77rxok

[Onex107]

I agree with Mike Smith on the aeroinjector. Once I insulated to eliminate the burps, and had the needle dialed in, I never touched the needle adjustment again for eight years. It's not a carburetor, the mixture has to be managed, but it's so simple. My adjustment acted exactly like Mike's. Full rich, stumble on takeoff. An inch out at full power and lean to a higher egt at cruise. I didn't do a lot of acro. Remember guys, at negative G's, depending on your tank vent setup, you could expel fuel. Don't get it on the windshield. Bad, bad. Replacing a windshield isn't easy.

[Bryan Cotton]

I've put a number of aerobatic flights on YouTube:

https://www.youtube.com/@mikesmith208/videos
https://www.youtube.com/watch?v=ctzIi77rxok

I subscribed a while ago. Thanks for posting these!

[mike.smith]

Remember guys, at negative G's, depending on your tank vent setup, you could expel fuel. Don't get it on the windshield. Bad, bad. Replacing a windshield isn't easy.

I did the up/down vent. It goes up a few inches above the cowl, turns 180 degrees down, then goes down the firewall to an exit at the bottom of the cowl. During some of my first acro, I saw fuel spit on the canopy. I didn't do any acro again until I made the new vent. As a bonus, I can get 17 gallons in my tank without any of it siphoning off.