The big AeroCarb/AeroInjector thread

How do you feel about your AeroCarb/AeroInjector

I love my AeroCarb/AeroInjector.
15
33%
I like my AeroCarb/AeroInjector but it took a bit of time and effort setting it up.
10
22%
I like my AeroCarb/AeroInjector now but it took too much time and effort to set it up.
4
9%
I neither like nor dislike my AeroCarb/AeroInjector, it does what it needs to and I am too busy flying to be bothered with this age old topic.
1
2%
I don't like my AeroCarb/AeroInjector but I trust it and will keep flying behind it for now.
2
4%
I don't like/trust my AeroCarb/AeroInjector and I am desperately trying to get it to run better.
3
7%
I hate my AeroCarb/AeroInjector and will replace it with something else (or have already done so).
11
24%
 
Total votes : 46

Re: The big AeroCarb/AeroInjector thread

Postby lutorm » Wed Oct 11, 2017 5:59 pm

sonex1374 wrote:Kerry talked about the tuning process on Episode 7 of SonexFlight, so that might be worth reviewing again for those just joining the conversation.

Interesting: I just listened to that episode and Kerry says (at 32min in):
Once you're at WOT and the EGTs have stabilized ... slowly pull the mixture control back and listen for your RPM to increase and you watch your EGTs and you are looking for an increase in RPM coupled with an increase in about 75-100 degrees. That tells you you're a bit on the rich side for WOT and that's what you want to be.

(my emphasis) He says nothing about the EGTs peaking or the engine starting to run rough. I interpret that statement as meaning you want the full rich EGTs to be 75-100 degrees lower than what they are at peak RPM ie. best power mixture, not 75-100 lower than peak EGT. This actually agrees pretty well with my impression, because peak power EGT is something like 125-150 ROP and full rich then becomes 200-250 ROP. See the plot below, for example.

But that description doesn't sound at all like what I read in the AeroCarb manual, which clearly says to lean until the engine begins running rough.

As for experimental vs not, the Aerovee is an air-cooled, four-stroke, two-valved, fixed-time spark-ignition engine running 100LL. It's similar to a Lycoming or Continental in every fundamental detail. A Rotax has some significant differences, ie liquid cooled heads, but operates on the same physical principles. A two-stroke, or diesel, rotary, or Atkinson cycle engines for that matter, are fundamentally different in their operation and I wouldn't apply any of the ideas here to those. But to say that an Aerovee is different in some way from a certified aircraft engine just isn't true.

Image
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Re: The big AeroCarb/AeroInjector thread

Postby sonex1374 » Thu Oct 12, 2017 11:52 am

lutorm wrote: I interpret that statement as meaning you want the full rich EGTs to be 75-100 degrees lower than what they are at peak RPM ie. best power mixture, not lower than peak EGT. ...[snip] ... But that description doesn't sound at all like what I read in the AeroCarb manual, which clearly says to lean until the engine begins running rough.

One of the main reasons for having Kerry go over the tuning instructions was to add better clarity and understanding to the process. I'm glad his explanations in the podcast helped clear things up.

Jeff
Jeff Shultz
Jackson, MS
Sonex TD, 3300, AeroInjector
http://www.sonex604.com
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Posts: 143
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Re: The big AeroCarb/AeroInjector thread

Postby lutorm » Thu Oct 12, 2017 2:38 pm

sonex1374 wrote:
lutorm wrote: I interpret that statement as meaning you want the full rich EGTs to be 75-100 degrees lower than what they are at peak RPM ie. best power mixture, not lower than peak EGT. ...[snip] ... But that description doesn't sound at all like what I read in the AeroCarb manual, which clearly says to lean until the engine begins running rough.

One of the main reasons for having Kerry go over the tuning instructions was to add better clarity and understanding to the process. I'm glad his explanations in the podcast helped clear things up.

Jeff

I don't know if it cleared things up, since we now have Sonex saying two almost opposite things... Kerry's explanation makes sense to me (and is largely what I did) so I'll follow that rather than the manual, but I think they need to rewrite the instructions in the manual to be consistent with that procedure, too. Maybe I'll email him and see what he says.
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Posts: 39
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Location: The Island of Hawai

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