AeroVee Performance (Cold Air Induction)

[WesRagle]

This brings me right back to my original question: "Does it seem strange to anyone else that a lot of folks just toss 8 HP without giving it a second thought?"

While in theory you may be losing 8 hp (~10%) I doubt that it is that much in the real world. Both Bob Mika and I used cool air induction and could not measure any difference in climb or speed performance from before we installed it. We both thought the engine "sounded" better.

Hi radfordc,

I find it surprising, shocking really, that you didn't see a substantial increase in performance. It just defies natural laws.

Questions:

Was your "cold air induction system" sealed all the way from outside the cowl through the carb?
Any pics of the setup you can share?

Thanks

[WesRagle]

I copied a lot of the Yahoo files here

http://www.sonexfoundation.com/Yahoo_files.html

Hey Robbie,

Do you still have access to the old Yahoo group files? If so, can you poke around in the AeroVee group pics and see if you can find any pictures of the induction system on #664? It's not perfect, it would just serve as another discussion point.

Thanks

[Sonex1517]

I can look this weekend. If I find them I will add them and post a link.


Sent from my iPhone using Tapatalk

[WesRagle]

Hi Guys,

Just wanted to make sure I'm not misunderstood so I wanted to make a couple of statements.

1) I am a HUGE Sonex fan. Should be obvious. I'm doing it again.
2) I am a retired electronics engineer. More than 30 years of my career were spent working in the engineering department of a small company where we designed instrumentation, monitors, and test equipment for turbine engines. So, I tend to obsess over numbers. Also, working for a small company I had to submit to "group think". I didn't like it then and I don't like it now. The difference is now I'm retired and don't have to submit to it. The long term results of group think are prejudices (pick your ism) and delusional thinking.

My reason for starting this thread is simple, I want to build the highest performance VW powered Onex that ever took to the skies. I think my chances of success are much better if I can find out what others have done to enhance the performance of their aircraft, Onex or otherwise.

Now, I'm going to ask a simple question. If the question offends anyone I would suggest they take a hard serious look at why they find it offensive.

Question:
Is there anyone, who lives outside of Wisconsin, who owns and flies a normally aspirated, AeroVee powered Sonex that can get in their Sonex, climb to 8000' and then maintain 150 MPH TAS in level flight?

If so, please chime in on this thread and help with the discussion.

Me, I almost made it. I didn't have a fancy panel but I was fully instrumented. I ran 3 ways, 4 ways, etc. I knew what the error was in my pitot-static system was and I knew how fast I was going. I could get 150 mph down low but at altitude I fell a little short. Presumably at higher altitude the fixed internal loses of the engine consumed a higher percentage of the available power so I could only hit about 145. I might have made it with a little more pitch in the prop but I couldn't talk myself into giving up climb to hit a number at 8000' where I rarely flew anyway.

Why do I think performance is so important?

1) Performance is fun.
2) Performance adds safety.
3) Performance sells air planes.

Anyway, I hope we can discuss ways to enhance the performance of out airplanes without offending anyone. I think it would be pretty cool if 10 years hence there was a proven solution for those who wanted cold air induction. Even cooler if the solution started with this thread.

So please, anyone with performance enhancing ideas pop in and keep the thread going. I'm all ears.

I need to get back to the shop or I'll never get to try anything :-)

Thanks

[radfordc]

Questions:

Was your "cold air induction system" sealed all the way from outside the cowl through the carb?
Any pics of the setup you can share?

Thanks

No, the system wasn't "sealed". It was an aluminum shroud wrapped around the air intake filter and a SCAT tube ducting fresh air to the shroud.

The pics are on this page: https://www.flickr.com/photos/32288421@N06/page3

[WesRagle]

I can look this weekend. If I find them I will add them and post a link.


Sent from my iPhone using Tapatalk

Thanks Robbie

Wes

[WesRagle]

No, the system wasn't "sealed". It was an aluminum shroud wrapped around the air intake filter and a SCAT tube ducting fresh air to the shroud.

The pics are on this page: https://www.flickr.com/photos/32288421@N06/page3

Thanks for the reply. Interesting pics. Seems like you would have seen at least some performance increase. I bet you would have if you would have totally enclosed the filter :-)

As an aside, it was fun looking at the old pics. I wonder if Gus is still flying his Sonex.

Thanks Again

[gammaxy]

Wes,

Yours is one of the more interesting threads that has been discussed lately. I'm interested in your experience with cold air induction and totally haven't interpreted anything you've said as offensive and don't think others have either.

I found plenty of references that provide numbers of 10%-15% power loss due to application of carburetor heat or alternate air, so in addition to your math seeming correct, it does seem to be in the ballpark of what would be expected. What would be surprising to me is if our intake air is the same temperature as an engine being fed by true carb heat.

Over the years, I've seen mentions of people trying it, but the results never seem to support the 10% difference you'd expect. You might be onto something by questioning whether their intakes were sealed.

I can get a little over 140 down low, but closer to 125-130mph at 8000 feet. Your numbers are the fastest I remember hearing for an Aerovee and do seem like they might be consistent with having 10% extra power. I'm unaware with anyone achieving 150mph TAS at 8000 feet. Nobody complains because they easily exceed the sea level number. Maybe cold air induction is the key.

[lpaaruule]

Questions:
Did you ever fly without cold air induction?
If so, what was the performance difference?
Do you have any pictures of your setup you can share?

Hi Wes. I haven't tried flying without cold air induction, but it would be as easy as removing the scat tube between the cowl and the airbox. I may try that.

Straight and level at around 3000 MSL I've seen 165 mph. I'm running too rich right now at over 11 GPH at WOT, so when I adjust the the Aerocarb maybe I'll get more speed.

I'll try to post a youtube video of my setup within the next week.

[builderflyer]

Hi Wes,

Good to see you back amongst the Sonex family members. You've been around long enough to remember that the first customer built Sonex to fly (Tony Spicer) utilized cold air induction on his Jabiru 3300. He used an Ellison throttle body because, I believe, the Aerocarb was not yet available. In reviewing his performance numbers utilizing two different props (Sensenich & Prince), when i began testing my airplane, it appeared that his plane didn't perform any better than mine which uses hot air induction with an AeroCarb.

But I've learned to not trust anyone's performance numbers, even mine, and I wish we had more opportunity to test one Sonex side by side with another for reliable bragging rights. Perhaps one or more of the Sonex gatherings could be used for that purpose and put to rest once and for all, who really does have the best performing Sonex out there for any particular airplane category and event.

Wes, as part of your quest for speed (or efficiency), will you be installing Van's pressure recovery wheel pants on your Onex as you did on your Sonex?

Art,,,,,,,,,,,,,,,,,,,Sonex taildragger #95,,,,,,,,,,,,,,,,,,,,,,,Jabiru 3300 #261