SonexBuilders.net

I must order my engine now, but I'm still a bit confused about the Aerovee and the aerocarb. Has anyone here done aerobatics with this setup? how does it handle maneuvers with several g's, like a loop? What about zero g maneuvers? does it stop? Will it run in a spin?

Lots and lots of people do aerobatics with the AeroVee. But there are caveats compared to other engines. Engines like the Jabiru 3300 (120 hp) have a much greater ability to power into and through aerobatic maneuvers. With the AeroVee many maneuvers will require you to nose the airplane over to gain enough speed to start the maneuver. Neither the AeroVee nor the Jabiru have inverted fuel or oil systems, so extended inverted flight or negative G maneuvers will eventually starve the engine of fuel and oil.

Sonex has a video of their Sport Acro version doing aerobatics:
http://www.sonexaircraft.com/aircraft/sa_test.html

Mike Smith

Buy the 2300 revmaster , turn key already dynoed , that's more time to spend on something else like time with family or friends , cause you don't have to build and engine , unless you would like to build the whole plane some people do, I run a revmaster and , been great ( knock on wood ) , two of my close friends are building Sonex and I talked them into goin with the revmaster , he just picked it up at fed ex a few weeks ago , very good engines , been around since the , 50,s joe is the owner , it's a small family run business , you call revmaster you talk to the owner joe in less than 3 minutes he is answering all of your questions , great people to deal with and have been in the business for years ,
Do some research before you order , not knocking aerovee , or any other engine ,.
Adam Simmons
Sonex541sx

SvingenB wrote:I must order my engine now, but I'm still a bit confused about the Aerovee and the aerocarb. Has anyone here done aerobatics with this setup? how does it handle maneuvers with several g's, like a loop? What about zero g maneuvers? does it stop? Will it run in a spin?

Positive G maneuvers with the AeroVee and AeroInjector are common and people have no issues with this setup. Just about any positive G maneuver will work just fine, including spins if you'd like.

As for negative G maneuvers, neither the engine or carb is really set up for negative G's. Momentary negative G maneuvers are okay, but prolonged inverted flight or negative maneuvers are to be avoided.

I received this video which pretty much answers all my questions :)

[youtube]http://youtu.be/7xYPJEaring[/youtube]

But I think at 4:40 or something I can see why I am asking. An Aerovee with gravity feed and an aerocarb will become rich when pulling g's and lean when decreasing g's. When he pulls up in a tight loop (around 3.5-4g) you can hear the engine revs down and roughens because it gets richer than optimal (at least that what I think, but I'm happy to be corrected). A carb with a float will not do this, it is unaffected by pulling g's (as long as it is not negative g where it stops functioning altogether). The leaning part seems to be a no issue though.

An Ellison or a Rotec TBI will also be unaffected by g's. They have a pressure regulator that keeps constant fuel pressure to the carb independent of feed pressure. The drawback is of course the regulator steals lots of pressure by itself, and a pump is needed for proper operation.

Seems like the Aerovee with Aerocarb is a good starting point (based on the video). The easiest path to a well functioning aircraft. By building the engine, I will be in a better position to make any modifications later if I want to. But there are several temptations; Revmaster, Sauer, ULPower

SvingenB wrote:I must order my engine now, but I'm still a bit confused about the Aerovee and the aerocarb. Has anyone here done aerobatics with this setup? how does it handle maneuvers with several g's, like a loop? What about zero g maneuvers? does it stop? Will it run in a spin?

Probably several hundred of us have done aerobatics with the Aerovee/Aerocarb. It works very well. Positive Gs don't have any effect on the carb that I have noticed. If you think you heard the engine changing speed during maneuvers it's because of the changing load on the prop, I believe. I've also done momentary zero G/negative G maneuvers and the engine ran fine. It certainly won't run during sustained negative G. Yes, it runs during spins.

With the Aerocarb, I cant' see why additional positive G's wouldn't cause a richer mixture. But, the relationship between the volume of the flow and fuel pressure isn't linear: Doubling the pressure should result in a change in the volume flowed past the Aerocarb needle of about 50%.

Yes, that is true. You need a 4 g pull up to get 100% more fuel to the engine. I remember similar situation for RC Aircraft (100 years ago :) ) The best position of the fuel tank was at the same level as the carb, as much as possible at least, and the tank was pressurized from the muffler. This would assure the least amount of variation in mixture for aerobatics. Today they have fuel pumps and EI etc or all electric motors.

The Aerocarb leaves much to be desired in terms of basic operational functionality, same as Revflow. But as long as it works with some minor fiddling with the mixture lever at "high" g, I guess it will do. A carb from Great Planes will be OK, but then carb heat is needed. A Rotec TBI would also be OK, but then electric pump is needed, two maybe to get some redundancy.

SvingenB wrote: But as long as it works with some minor fiddling with the mixture lever at "high" g, I guess it will do. A carb from Great Planes will be OK, but then carb heat is needed. A Rotec TBI would also be OK, but then electric pump is needed, two maybe to get some redundancy.

That's how I see it. People are doing aerobatics with the Aerobcarb and the engine keeps running through the bottom of loops, split-S's and similar high-g maneuvers, so that's good enough for me. If I planned on competitive aerobatics maybe the answer would be different. But the simplicity and weight savings from eliminating the fuel pump and carb heat pay off the other 99% of the time I'll be at, effectively, 1-G. It's another aspect of that "reality check."