Engine Reliability?

[mcjon77]

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I think the root cause is proven...it's bubbles in the fuel caused by hot gas vaporizing in the fuel line. When these bubbles reach the Aerocarb you get a "burp". This happens most often with Mogas and especially when running "winter blend" that has a lower vapor pressure.
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That is what I remember too. IIRC, the "burping" issue wasn't limited to Aerovees. Jabirus that were using the Aerocarb instead of the standard bing carb also had that issue (this is me going off memory from the old yahoo list, so I could be wrong).

[Onex107]

You are correct about the "burps" and "winter auto gas". It changes to summer gas about 4-1. I went through a series of "fix's" for the burps. First added a blast tube to the AeroInjector and wrapped the exhaust pipes, second insulate the fuel line, third insulate the gascolator, fourth remove the gascolator (it's difficult to insulate), fifth slope the fuel line down hill all the way and double insulate with two sizes of hardware store foam pipe insulation doubled up. I don't use fire sleeve, I don't know how well it insulates. Some where along there Sonex increased the opening in the bottom cowl. Finally success. 210 hours with no burps at any temp. The worst it got was burping at cruise about every three seconds. Very scary. The engine dies and restarts constantly until you land. With this happening I could maintain altitude, but if it happened on takeoff and climb out it would be a serious problem. Look for it to begin initially, when outside temps start to increase, the first indication is after you land and it begins to burp during taxi when everything is getting heat soaked. It if happens then, it will eventually happen in flight. Insulate, insulate, insulate.

[radfordc]

My case of the serious burps was in April on a day that the OAT was in the 70s. The winter blend gas in the tank started vaporizing and the engine would not give enough power to maintain altitude. Luckily I was near the airport and landed OK. After landing the engine died completely and wouldn't restart until it cooled down.

[daleandee]

That is what I remember too. IIRC, the "burping" issue wasn't limited to Aerovees. Jabirus that were using the Aerocarb instead of the standard bing carb also had that issue ...

You are quite correct. The problem with burps isn't the engine it's the Aerocarb. I was excoriated on this list for giving my personal opinion on the Aerocarb so I dare not repeat it. But I believe this "burping" issue is serious enough that every new builder that intends to use an Aerocarb should be made aware of it.

Here is a video example of the burps: https://www.youtube.com/watch?v=S6GD5s7osHE

If my airplane did that on the take-off roll it would be back in the hangar. My airplane should run at least as good as the truck I drove to the airport.

Dale Williams
N319WF @ 6J2
Myunn - "daughter of Cleanex"
120 HP - 3.0 Corvair
Tail Wheel - Center Stick
Signature Finish 2200 Paint Job
171.9 hours / Status - Flying
Member # 109 - Florida Sonex Association
Latest video: https://www.youtube.com/watch?v=1VP7UYEqQ-g

[mike.smith]

You are quite correct. The problem with burps isn't the engine it's the Aerocarb. But I believe this "burping" issue is serious enough that every new builder that intends to use an Aerocarb should be made aware of it.

AeroVee and AeroInjector. No gas collator. Fire sleeve and one other layer of plumbing pipe insulation, held in place with reflective heat tape. Not a single burp in 3 years and 270 hours.

[ScottM-Sonex1629]

AeroVee and AeroInjector. No gas collator. Fire sleeve and one other layer of plumbing pipe insulation, held in place with reflective heat tape. Not a single burp in 3 years and 270 hours.

My setup is very similar to Mike’s, except I have the gascolator still installed on the firewall.

I also wrapped my standard stainless exhaust...and have never had a burp. Always use 100LL, never MOGAS or ethanol blended fuel. Almost 2 years and 80+ hours...with the only issues the ones I created by excessively leaning the engine last year during my annual.

Do those of you trashing the AeroVee realize what you are doing to the reputation and resale “value” of the engine and our aircraft? I’m tired of reading about the generalizations of a few on the entire fleet of AeroVee’s. It’s a public forum and it’s hurting the brand and the engine.

If assembled with care, and attention to detail with the FWF is taken (and insulating the fuel supply line), the engine runs great.

[rizzz]

Do those of you trashing the AeroVee realize what you are doing to the reputation and resale “value” of the engine and our aircraft?

I’m sorry but (and I’ll put this as nice as I can) this is a very selfish comment to say the least.
Is the resale value of your, or even all AeroVee/AeroCarb powered aircraft worth even one single life? “Burps” as in the video link shown or the ones another poster descibed above are dangerous, full stop.
If people experience such dangerous events they should be allowed to talk about it over and over again on public forums, yes, for sure! And if there are ways to “fix” the problem, of course we should include that into the discussion as well, absolutely!

Now that said, here’s my 2 cents.
I have an AreoCarb on my 2.4l VW engine. My exhaust is wrapped and all fuel and oil lines are insulated, I do have a gascolator though.
I have had “hickups”, I would not even call them burps, they’re just very short stutters, nothing like what’s shown in the video above, and they only happen on hot days (not uncommon where I live) with a hot engine and most importantly, only as I’m pushing the throttle forward for takeoff, after that she runs smooth.
I’ll see if I can find a video and post it here.

So in my experience, I have not been successful in eliminating the burps entirely but almost, peharps getting rid of the gascolator would get rid of the last little “hickups” completely.
My opinion is that AeroCarbs are great because the installation is so simple, but they do need some special care that normal carbs don’t require. This must be reiterated over and over again.

I’m sorry if you think this information is damaging to the resale value of your aircraft, I find it valuable to share with the community.

[radfordc]

Once I insulated all the fuel lines and the gascolator with firesleeve, foam pipe insulation, and aluminum reflective tape I never had another problem with burps, even with Mogas.

[radfordc]

Do those of you trashing the AeroVee realize what you are doing to the reputation and resale “value” of the engine and our aircraft? I’m tired of reading about the generalizations of a few on the entire fleet of AeroVee’s. It’s a public forum and it’s hurting the brand and the engine.

Do you consider Sonex's service bulletins to also be "trashing" their reputation? I agree that a disgruntled owner may sometimes go off the deep end with criticism, but that is part of being a "community".

[kmacht]

Once I insulated all the fuel lines and the gascolator with firesleeve, foam pipe insulation, and aluminum reflective tape I never had another problem with burps, even with Mogas.

That's great but how many of the 500+ builders out there know that is what needs to be done? How many will go do their first flight without knowing any better and experience the burps? Are you sure none of the takeoff accidents weren't because of the burps? It's a bandaid for the problem, not a solution. A real solution would be to redesign the aerocarb so it isn't susceptible to air bubbles in the first place. Failing that a service bulletin from the factory with actual testing behind it detailing how to setup a fuel system that doesn't create the burps should have been issued a long time ago. Instead the factory continues to ignore the problem and hope others figure out something that works for them. Some have, I bet many have not.

Keith