Vetterman Fairing

While nearing completion of my RV6, I saw pictures of a fairing Larry Vetterman made for his plane. The idea of the fairing was to reduce the noise inside the cockpit. The side benefit was a several MPH increase. That got my attention since speed was always on my mind throughout this build. What's another two weeks after ten years....so I decided to copy this fairing and enjoy Larry's free speed.

After flying with and without this fairing for several hours it was clear there really was an increase in my airspeed but...my normal oil and cylinder head temperatures ran higher, 15 & 30 degrees, and this was on cold winter days. So my new fairing would be a little tight come summer in Oklahoma and it was time for a mod or version 2.

This mod keeps all my tempertures right at normal and recovery after a long climb went from 20 minutes to about 5 minutes to back to normal. Was it worth all the effort to make? Yes and I'd do it again. I know the big question is how much speed increase do I get with this fairing installed? First, all my testing was done at a pressure altitude of 5,000 feet and at as near the same tempertures as I could get. With cold winter air there is a 5 to 6 MPH increase with the fairing installed. On a hot summer day I'm seeing 4 to 5 MPH increase in true airspeed. So for an old countryboy figuring, I'd say the fairing is good for 5 MPH on my plane for sure.

Looks Great!

thanks for the pictures!

will be onto something similar, probably this winter.
how did you start with the shaping? any tricks?

rgds, bernie

Hey Bernie ... geniesse Deine Frau und die Ferien!

Kannst es wohl nicht lassen ...

Take a piece of blue foam, shape it in a horizontal view from the side and from the front, then in a vertical view, start to cut the corners to 45? untill all is symetrically, then round off all the corners ans lay down 2-3 layers of glas cloth and epoxy.

Remove the foam by thinner or aceton and build up the rest from the inside.

Maybe you want to brush on a ceramic coating in the area of the exhaust tubes.

As you know, my door is open ... i will do the same, but mine would not fit onto your cowl so you must do yours by yourself.

Have a good and save trip back with your sweet travel-machine

Gruss Domi

Just curious if you thought you had a reduction in exhaust noise.

Also, what is the rationale for the louvered area?

Mike

Beautiful glasswork!

I would pay some $$$ for a good drawing and detailed description of how you did it. Hint...hint.
I'd pay even more for one already made. Hint...hint...hint.

alcladrv said:

Just curious if you thought you had a reduction in exhaust noise.

Also, what is the rationale for the louvered area?

Mike

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The louvers are for additional cooling air to get out. If you'll look at the first photo you'll see there are spaces on each side of the exhaust tunnel. These spaces scavenge more air from inside the cowling. By doing this the sides of the "Vetterman Fairing" are faired into the cowling very cleanly. The whole idea here is to clean up air flow. As for a reduction in exhaust noise there was a very noticable reduction in cabin noise. Sorry I forgot to say anything about noise but I did this for the speed and got it too.

jarvis said:

I would pay some $$$ for a good drawing and detailed description of how you did it. Hint...hint.
I'd pay even more for one already made. Hint...hint...hint.

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Maybe I just need to post a few more photos of the "Vetterman Fairing". It's not a hard project if you don't mind fiberglass and have an eye for carving foam. Then fill and sand then fill and sand,ect......... To do one right it needs to be fitted to it's airframe. Remember these are homebuilt so all may look alike but they are not the same. PM me and we'll talk......

5 MPH is a Really Big Jump in Speed

IOldguy, your speed increase with this mod is impressive. Have you considered flying in one of the SARL (www.sportairrace.org) cross country air races? I would assume you would do quite well. Your work along with Jim Smith's refines my knowledge of the effects of the Vetterman mods in this area.

Some observations:

Since you put in the exit ramp across the entire area of the exhaust pipes:


Bob Axsom

Bob Axsom said:

IOldguy, your speed increase with this mod is impressive. Have you considered flying in one of the SARL (www.sportairrace.org) cross country air races? I would assume you would do quite well. Your work along with Jim Smith's refines my knowledge of the effects of the Vetterman mods in this area.

Some observations:

Since you put in the exit ramp across the entire area of the exhaust pipes:

Does the leading edge of the ramp seal to the fuselage forcing all cooling air to pass through this area?

If so, have you blocked off the central louvers aft of the pipes?

Why do you have the side louvers in the cowl?
​

Bob Axsom

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The leading edge of the exhaust ramp rolls up into the engine compartment making a smooth transition for the air to follow. There really is no seal just a good tight fit. The first version of the fairing required the removal of the cowling to take the fairing off. Real pain in the butt when doing testing. "What was I thinking". Second version can easily be removed any time. I'm a bit slow but I do learn.
Louvers are still there and working. Notice my first photo, there are air tunnels on either side of the exhaust ramp taking additional air from inside the cowling and venting out the rear louvers. On the first version I made a cowl flap set up on the louvers so I could shut them off but I found I could never run them closed in even Oklahoma winters. Took that part of the louvers off. Now if you lived up north where you have real winters this could be a good option. But what this did do was show me my side tunnels are working as I thought they would.
The side louvers were just insurance for getting a little more air out of the cowling incase the fairing turned out to be to restrictive. Larry Vetterman had these extra louvers on his version of the fairing installation but he put the louvers on the bottom of his cowling. Not a good place, this is a very high pressure area which would not be good for venting the cowling. So on the side they went. As low and as far back as I could put them on a flat part of the cowling. Also note my side louvers stick inside the cowling not out as the buttom ones do. Less drag, I hope anyway. Beside I just think they look really very neat there.
As for going to any formal racing most likely not. I flew competion aerobatics for 23 years and had a blast but....I know my personality and if I ever start I'd be hooked and have to try to win. Now retired and funds are not what they use to be. Life's to short the be wound up tight all the time. I did think speed all the time I was building my 6. I do have a very (I think) fast 6 for one with a 0320 in it. Best thing about it is I can putt around at a good crusing speed and not burn much fuel. "**** I am getting old".... Hope this helped clear a few things up I left off of my first post. Need anything else let me know. Oh, it did lower the noise inside the cockpit some. Larry Vetterman had a great idea with this fairing set up. I just wish I could take some credit for it. This is such a great sight for sharing ideas and making our planes better. Thanks Dan for being here!

Beautiful work and is causing me to consider this as my next big project. It's not a surprise that your plane is fast when I see your fuel drains faired in one of the photos. Wee bit of attention to drag details

All Best

Jeremy

1Oldguy said:

As for going to any formal racing most likely not. I flew competion aerobatics for 23 years and had a blast but....I know my personality and if I ever start I'd be hooked and have to try to win. Now retired and funds are not what they use to be. Life's to short the be wound up tight all the time. I did think speed all the time I was building my 6. I do have a very (I think) fast 6 for one with a 0320 in it. Best thing about it is I can putt around at a good crusing speed and not burn much fuel. "**** I am getting old".... Hope this helped clear a few things up I left off of my first post. Need anything else let me know. Oh, it did lower the noise inside the cockpit some. Larry Vetterman had a great idea with this fairing set up. I just wish I could take some credit for it. This is such a great sight for sharing ideas and making our planes better. Thanks Dan for being here!

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I cannot tell you how big of an impact you would have on the Sport Air Racing League with your RV Red class airplane. You could probably win everything in sight including the SARL Experimental National Championship Trophy and the Air Venture Cup race. Chris Murphy in his O-320 powered RV-4 often flies alone and several races have no RV Red entries at all. The racing is cross country against the clock in many classes with the fastest plane launched first. You seldom see another airplane shortly after launch and the comaradrie is of the helpful and friendly competitive kind. However, you know yourself better than anyone as well as the economic situation. Good luck with your quest for speed.

Bob Axsom

Speed Reference

Enter www.sportairrace.org, click on "Records and Stats", then "League Statistics", then "All Speeds by Class" and/or "All Speeds by aircraft Type" and you will download Excel files with speeds you would be interested in to gauge your progress without racing.

My current speed (TAS) at 6,000 ft dalt is ~184.4 kts with an O-360-A1A.

Bob Axsom

Bob Axsom said:

Enter www.sportairrace.org, click on "Records and Stats", then "League Statistics", then "All Speeds by Class" and/or "All Speeds by aircraft Type" and you will download Excel files with speeds you would be interested in to gauge your progress without racing.

My current speed (TAS) at 6,000 ft dalt is ~184.4 kts with an O-360-A1A.

Bob Axsom

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Thanks Bob, I'll take a look. What happens when one gets lost in one of these cross country races? I have been know to get just a little bit, let's say disoriented, from time to time. Hate to keep everybody waiting on me to show up....

if you think you're lost, just slow up a bit and when the guy behind you zooms past, just get on his tail and follow him home.

The races left from September to end of Season 2011

I went to www.sportairrace.org and copied what is left in the Calendar of Events for 2011. Nothing really close to Oklahoma. Usually the organizers go to significant lengths to assure that the turn points are highly visible but even then it is good to do a detailed flight plan and mark the course on a sectional and input the course into a GPS receiver. I make up a kneeboard checklist for the race with a page for the start, all the turn points and the finish. On the pages I have the required altitudes, enroute altitudes I intend to use based on winds aloft forecast, frequencies, broadcast requirements for turn points and finish and hazards (towers, etc.). There is definitely a navigation requirement and at low altitude and high speed it is harder than higher up. Occasionally someone will not finish and the program goes on but they do provide a race frequency and usually a phone number for racers to report their situation.

Bob Axsom

The Tennessee 100 Air Race
10 September, 2011
Tullahoma, TN (THA)

The Pagosa Springs 130 Air Race
24 September, 2011
Pagosa Springs, CO (PSO)

The Northwoods 100 Air Race
24 September, 2011
Waupaca, WI (PCZ)

The Lancaster 150
1 October, 2011
Lancaster, PA (LNS)

The Thunderbird 150 Air Race
8 October, 2011
Wickenburg, AZ (E25)

The Cleveland Air Race Revival
15 October, 2011
Cleveland, TX (6R3, LFK alternate)

The Tennessee Valley Air Race IV
29 October, 2011
Courtland, AL (9A4)

The Rocket 100 Air Race
19 November, 2011
Taylor, TX (T74)

Actual Race information is worth looking at

The next race is this Saturday in Tullahoma, Tennessee. If you look at the race information provided that will give you a feel for the race navigation requirements. There is too much to copy but if you go to www.sportairrace.org and click on Calendar of Event, then click on The Tennessee 100 Air Race, then click on Tennessee 150 Air Race Information [sic], the first thing you see is the course layout on a sectional. After that there is direction, distance, and Lat/Long information followed by overhead photographs of all the turn points with inbound and outbound course lines. In this particular case airports are used for most of the turns. As you fly into airports they usually are visible from five miles away but look at turn 2 ... it looks like a grass runway. I HATE those green nondescript strips of green in a field of green turn points and this requires noting the highway location and the building locations to help pick it up. Turn 3 looks easy but if your altitude is low and the trees are high this may be difficult to spot until you are very close.

You can study the rest and get the idea of the navigation and planning requirements.

Bob Axsom

Racing

Bob Axsom said:

The next race is this Saturday in Tullahoma, Tennessee. If you look at the race information provided that will give you a feel for the race navigation requirements. There is too much to copy but if you go to www.sportairrace.org and click on Calendar of Event, then click on The Tennessee 100 Air Race, then click on Tennessee 150 Air Race Information [sic], the first thing you see is the course layout on a sectional. After that there is direction, distance, and Lat/Long information followed by overhead photographs of all the turn points with inbound and outbound course lines. In this particular case airports are used for most of the turns. As you fly into airports they usually are visible from five miles away but look at turn 2 ... it looks like a grass runway. I HATE those green nondescript strips of green in a field of green turn points and this requires noting the highway location and the building locations to help pick it up. Turn 3 looks easy but if your altitude is low and the trees are high this may be difficult to spot until you are very close.

You can study the rest and get the idea of the navigation and planning requirements.

Bob Axsom

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Well you do have me thinking now. My competitive jucies are starting to move around. Maybe next year. Got to get my canoe fairings on and a new fairing for the tail end made this winter. Got to love these airplanes, try to make a certified airplane faster and it will cost you an arm and a leg. All you need with our expermential airplanes is an imagination and some elbow grease.

Some Basic Dimensions......Please

Just today I discovered the Vetterman website and found his thoughts on the exhaust fairing really interesting. It looks like a pretty straight forward project but I would lke to start with your basic dimensions like total length and thickness (height). Any chance of an outline tracing?

In Vetterman's second edition he deletes the fairing louver but since he has two louvers in the cowl that may be all he needs. In Vetterman's first prototype his CHTs went up about 30 degrees. That is too much for me but it looks like cutting out the entire area arounds the exhaust stacks did the trick for you.

It seems like the sides of your stacks are very close to the fiberglass. Have you experienced any temperature issues?

I think you'll find that the fairing on Jim Smith's RV-6 without the louvers is much easier to build. He does 202 at 8000' dalt, 201 mph at 10,000' dalt, on 150 HP, and you can make it out of aluminum.

I think you'll find that the fairing on Jim Smith's RV-6 without the louvers is much easier to build. He does 202 at 8000' dalt, 201 mph at 10,000' dalt, on 150 HP, and you can make it out of aluminum. It works on the Coanda effect

Pictures

elippse said:

I think you'll find that the fairing on Jim Smith's RV-6 without the louvers is much easier to build. He does 202 at 8000' dalt, 201 mph at 10,000' dalt, on 150 HP, and you can make it out of aluminum. It works on the Coanda effect

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Paul, can you link to some pictures of Jim's fairings?

I wonder what having both mods would do to your speed?

What?

elippse said:

I think you'll find that the fairing on Jim Smith's RV-6 without the louvers is much easier to build. He does 202 at 8000' dalt, 201 mph at 10,000' dalt, on 150 HP, and you can make it out of aluminum. It works on the Coanda effect

Click to expand...

What's the Coanda effect I too would like to see pictures of Jim's fairing. Thomas any clean up of your airframe will help make your plane more efficient/faster. But as your mods increase the results lessen. So the question is how much work are you will to do for very small gains?
The louvers really are not a problem to install it's more a cost issue for the louvers themselves. I am going to do alittle more testing with the louvers though, version 3, just have a hard time leaving things alone.
I have tried to stay away from posting any speeds of my plane but it does pretty good on a 320 also. Coming home from the "Badlands" this weekend at 9,500 pressure altitude we were truing out at 174 mph, 50% power, 6.4 gph, 2,450 rpm. We were heavey with all my wifes stuff for a long weekend.
One other thing about our plane I have not mentioned is we are running a fixed pitch "Performance Propeller" which I am very happy with.

1Oldguy said:

What's the Coanda effect I too would like to see pictures of Jim's fairing. Thomas any clean up of your airframe will help make your plane more efficient/faster. But as your mods increase the results lessen. So the question is how much work are you will to do for very small gains?
The louvers really are not a problem to install it's more a cost issue for the louvers themselves. I am going to do alittle more testing with the louvers though, version 3, just have a hard time leaving things alone.
I have tried to stay away from posting any speeds of my plane but it does pretty good on a 320 also. Coming home from the "Badlands" this weekend at 9,500 pressure altitude we were truing out at 174 mph, 50% power, 6.4 gph, 2,450 rpm. We were heavey with all my wifes stuff for a long weekend.
One other thing about our plane I have not mentioned is we are running a fixed pitch "Performance Propeller" which I am very happy with.

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Are you going to be at the Guthrie airport fly-in on September 24th? If so, I would like to talk with you. I have been interested in an exhaust exit fairing every since getting my cowl built.

Guthrie Fly In

Yes I'll be there. Looking forward to meeting you and talking RV's. The "Badlands" was our first long cross country in the 6, now my wife has the RV grin also and mine is even bigger than before. What a great traveling machine these RV's are.
Steve give me a call you don't have to waite for the flyin to come up. Also any and all RVs in the area come to Guthrie (KGOK) Saturday the 24th, like to have a good showing of RV,s here. FAA will have their altitude chamber here so you pilots can experience hypoxcia (sp?). Good food and several warbirds. Young Eagle flights. Should be a good reason to get out and fly to Guthrie that morning.

1Oldguy said:

Yes I'll be there. Looking forward to meeting you and talking RV's. The "Badlands" was our first long cross country in the 6, now my wife has the RV grin also and mine is even bigger than before. What a great traveling machine these RV's are.
Steve give me a call you don't have to waite for the flyin to come up. Also any and all RVs in the area come to Guthrie (KGOK) Saturday the 24th, like to have a good showing of RV,s here. FAA will have their altitude chamber here so you pilots can experience hypoxcia (sp?). Good food and several warbirds. Young Eagle flights. Should be a good reason to get out and fly to Guthrie that morning.

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I am planning to make it up to Guthrie on the 24th. I will try to look you up when I get there but keep an eye on arriving RV's. If you see my red/white 9A (446RV) make sure to come over and say hello. Otherwise you might only be able to find me because I will be the one bending over looking at the belly of all the RV's trying to find exhaust fairings.

Steve,

There is a lot more to look at on Joe's plane than just the exhaust fairing. He's built a bunch of go-fast into that thing. I hope to see both of you there.

You won't make fun of me if I do goofy stuff in the altitude chamber before passing out will you? This might be a "double dog dare" opportunity that could result in some new call signs.

Joe

Looking forward to seeing all of those mods.

As far as any hypoxia joking around, well, I will reserve that for others as I am sure if I end up in that "chamber" it would not be pretty.