AeroVee Performance (Cold Air Induction)

[WesRagle]

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

Hi Art,

Great to hear from you! Hearing from members of the old gang makes me feel not so old.

Yea, I was looking at the link Robbie posted that contains some of the old Yahoo Group info. A brief write up on Tony's setup is preserved there.

Having a side by side fly off sounds like a great idea, and lots of fun.

As for the wheel pants, funny you should ask. I just looked for my old copy of ?? Years of the RVator so I could site where Van said they gained about 5 mph (I think) when they made the switch to pressure recovery wheel pants. However, it seems the book fell victim to the great shop cleanup earlier this year in preparation for the Onex build :-(

Last I recall you were installing pressure recovery wheel pants. Maybe you can provide us with a data point. Any performance increase?

As for me, performance increase or not, I think they look cool. So yes, it has already begun ;-)

The first pic is of a test fit of a pant that I totally destroyed while trying to fit it to the Sonex. I test fit it to see if I could make it work with the Onex style landing gear. It looked promising so went ahead and got a set for the Onex. They fit the Onex style gear much better/easier than the Sonex style gear. A single slit in the aft half and they slide right on.

[WesRagle]

Deleted

[DCASonex]

[quote="
Hi radfordc,

I find it surprising, shocking really, that you didn't see a substantial increase in performance. It just defies natural laws.
******************
The introduction of SCAT tubing when converting to cool air intake adds a lot of turbulence and thus restriction to airflow. That may have offset the improvement from breathing cooler air vs. having the air filter directly on the carb, but breathing air heated by cylinders.

David A.

[SonexFactoryTech]

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.

It is important to remember that comparing airspeeds between airplanes is useless unless all reporting parties have calibrated their airspeed indicators and are quoting True Airspeed (TAS), not indicated airspeed, not ground speed, not what some people call "GPS speed" (which is ground speed). The only accurate comparison method for aircraft speed is True Air Speed and few aircraft owners take the time to calibrate their airspeed indicator to allow accurate TAS calculations. Even if your digital instrument displays TAS it is only accurate if the pitot, static, and outside air temperature sensors are accurate.

The ultimate example of the inaccuracy of indicated airspeed is the Space Shuttle. In orbit, its airspeed indicator would have read zero while the shuttle orbited the earth at 17,320 mph.

Blue Skies....

Kerry Fores
Technical Support Manager
Sonex Aircraft, LLC

[lpaaruule]

Thanks for the reminder Kerry. The 165 mph was simply the indicated. I did have my pitot and static system verified by the same guy the checked out my transponder. I’m actually very happy with the performance, though my friend with the Zodiac 601 isn’t :-)

BTW, that’s without wheel pants.

[builderflyer]

It is important to remember that comparing airspeeds between airplanes is useless unless all reporting parties have calibrated their airspeed indicators and are quoting True Airspeed
Blue Skies....

Kerry Fores
Technical Support Manager
Sonex Aircraft, LLC[/quote]


Kerry is so right on this..........I have the plans pitot-static system on my Sonex and found the IAS to read 15 mph high at 150 mph. I literally spent hours and many flights calibrating the system with the result being that my Sonex is no longer the "fastest" one out there.

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

[WesRagle]

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.

Hi Chris,

Been out of town with only a tablet. I hate to try to peck out a reply on those things.

My experience, with "cold air induction" was all good. However, I never flew without it so I really don't know how much it added to performance. I am sure I helped. I flew down to the "Great Southern Sonex Gathering" one year with a couple of other VW powered Sonex's and could pass them easily. I was two up and they were one up so they could out climb me but I could still out run them.

I just enjoy thinking about such things. It is one of the ways I have fun with a Sonex. But do keep in mind. It's not my thread, it is just a thread in which I made the first post. Discussion forums are for entertainment purposes only and Sonex LLC always gets the final say. I'm just having some fun and trying to spark some good natured discussion and, as Art suggested, maybe some good natured competition. I couldn't and wouldn't make any serious mods to the airplane. However, I will try to grab some low hanging fruit in an attempt to go a little faster, just for fun.

I want to tell a little story and then I'll get back on topic.

Ten or twelve years ago I owned three airplanes. A C-150 in which my wife, my son and I earned out licences. An O-360 RV-6A with a constant speed prop, and an Aerovee powered Sonex. One of our hangars was an end T hangar which means it had a little extra room. One of the former tenants had used that extra room to build a little room in the hanger. The room was air conditioned and had a fold out sleeper sofa. I would spend all weekend at the airport. Sleep in the hangar and shower at the FBO. As the locals put it, "I was eat up with it".

Now, as will happen from time to time, some of my airplane buddies decided we should all get together and take a trip. This time I think we went to Santa Fe New Mexico, about 500 miles from my home base. All of these guys flew RV's, I had an RV, so the choice of airplanes was obvious, I'm going in the RV.

The week before the trip was a fire drill. The RV was out of annual. Among other things I had to perform a compression check and check the mag timing. While reinstalling the cowl I hit my head on the transponder antenna and broke that dang thing off (the antenna not my head). I had to get a new antenna shipped over night so I could fix that in time. The whole week went like that. Just a fire drill. It had been so long since I had flown the RV that one of my buddies, a professional pilot, was concerned about my currency. To make him happy I had to take a check ride with him to prove I could still fly the RV. BTW, of course I could, if you can fly a Sonex you can fly an RV.

Looking back on it I think it speaks volumes about the Sonex. Any time I went flying just for fun (which was 90% of the time) the airplane I pulled out was the Sonex. Why? Well, I guess that is a topic for a different thread.

Here is fun video just to get you in the mood to try some stuff :-)

"https://www.youtube.com/watch?v=1vTm8vZ-5aM"

[WesRagle]

It is important to remember that comparing airspeeds between airplanes is useless unless all reporting parties have calibrated their airspeed indicators and are quoting True Airspeed (TAS), not indicated airspeed, not ground speed, not what some people call "GPS speed" (which is ground speed). The only accurate comparison method for aircraft speed is True Air Speed and few aircraft owners take the time to calibrate their airspeed indicator to allow accurate TAS calculations. Even if your digital instrument displays TAS it is only accurate if the pitot, static, and outside air temperature sensors are accurate.

The ultimate example of the inaccuracy of indicated airspeed is the Space Shuttle. In orbit, its airspeed indicator would have read zero while the shuttle orbited the earth at 17,320 mph.

Blue Skies....

Kerry Fores
Technical Support Manager
Sonex Aircraft, LLC

Hi Kerry,

With GPS I think it is pretty easy to talk about TAS these days. On a calm wind day TAS, GPS Speed, and Ground Speed are the same (except for very minor errors inherent in the TAS formula itself). Unless I'm confused, a 4 way GPS run using IAS only to verify stable flight before taking GPS data will give TAS and you don't have to worry about instrumentation or installation errors. On a bumpy day I wouldn't even try.

The thing I had trouble with was altitude. I believe an apples to apples comparison can only be made quoting TAS at a specific Density Altitude. Now you are right back to all the error sources you sighted. Where I live there a few mornings each year, usually after a frontal passage in the Spring or Fall, when the AWOS is reporting calm winds, altimeter setting 29.92, and density altitude the same as field elevation. There you have it, just for a little while the elusive "Standard Day".

It was on such a morning that I made my one and only attempt to get 150 mph TAS at 8000' Density Altitude. I didn't quite make it.

Anyway, it's just a number. It's not even an important number. All Sonex aircraft are plenty fast. I just have fun with numbers.

I wish Andrew would pop in and make fun of me. I would make it a lot easier to back myself out of this mess :-)

All the Best

[builderflyer]

Wes,

I didn't do any serious testing after installing the Vans wheel pants but I didn't notice any significant performance increase. What I've told others who want to do the same is "do it for the looks and not for the performance and you won't be disappointed". I spent a considerable amount of time modifying the stock Van's nose wheel pants and adding a cuff to match up with the the gear leg fairings of the Sonex. Sorry for being off topic.

Good to hear from you,

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

[WesRagle]

Wes,

I didn't do any serious testing after installing the Vans wheel pants but I didn't notice any significant performance increase. What I've told others who want to do the same is "do it for the looks and not for the performance and you won't be disappointed". I spent a considerable amount of time modifying the stock Van's nose wheel pants and adding a cuff to match up with the the gear leg fairings of the Sonex. Sorry for being off topic.

Good to hear from you,

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

Hi Art,

I think it would be hard to measure the effect of a single change. It must be good for at least a couple of MPH though. The pants were difficult for me to apply to a Sonex. Much easier on the Onex. Discussion of wheel pants shouldn't be off topic. The title I chose for the thread is unfortunate. Maybe we should shut this thread down and start a new one. How about "Sonex/Waiex/Onex, find me a milliknot"? Any ideas? And thanks, good to be back.

Wes