A

AirWolf

Active Member
I'm starting on the baffling for my 9A, and I have some questions right out of the box...first, the 'instructions' (as they don't instruct very well) say to put the lower cowl on to fit the baffling...if you do that, how do you get the lower pieces in place? Wouldn't it be easier to get the baffling put in place, and then fit the cowling?

Alright, now to the real question. I started to fit the outboard sidewalls first (with the lower cowl on) and I was able to get parts 4 and 8 (rear parts) on just fine, but the front parts (3 and 9) don't fit inside the cowling, as they are too long, and they stick out. I'm assuming that this is normal for the 9's and a 320? If others have seen this, how did you trim the pieces...I'm assuming(again) that I'll just start hacking away until they fit snugly inside the cowling?

Also, on Step 6, the instructions say "Fabricate the retention clips from .040" 2024T# aluminum and install after engine to cowl gap clearance is trimmed"....what engine to cowl gap clearance are they talking about?

If anyone knows of a good site that has a good number of pictures of the baffling installation (preferrably in a 9, but not necessary), I'd really appreciate it if you could post the link here!

Thanks for the help,
Ron
RV-9A
 
Baffles

Ron-
Get ready for about a months worth of work! They don't call them Baffles for nothing!
Your right, you can do a lot of the initial work with the bottom cowl off. Before you're thru, the bottom (and top cowl) will be on and off MANY times. You can pretty much fit both sides and the back before you need to start fitting to the lower cowl. You'll need the lower cowl on to trim the sides and fit the front ramps. You are correct in that you'll basically start cutting the extra length on the front side pieces a little at a time until they just fit inside the lower cowl inlet lip.
The gap they are talking about is the gap between the baffling and the top (and/or bottom) cowl. That gap is to allow for engine movement inside the cowl. You don't want the baffling hitting the cowl while the engine is running.
Sorry I don't have any pictures. There are some good ones out there, hopefully someone will jump in and point you in the right direction. The baffles are like a jigsaw puzzle, they will fit together pretty good once you study the instructions while fitting the pieces to the engine, but, like a puzzle, it will take a while to get it all together! You just have to keep at it!!
Good Luck!
Bill Waters
 
Ron:

I used pictures from Rick Threet's webpage....

http://our-rv7a.com/finishing_kit/finishing_kit.htm

Page down and you will see where he starts on the baffles on December 2, 2003. His is a 7A, but the baffles are pretty much the same for the 9.

If you get stuck anywhere, just give me a holler and I can take a digital of any area you need. I have a 6A with an O320 E2D, but as with the 7, I don't think there is any difference in the baffles.


Regards,

Jeff Orear
RV6A N782P (reserved)
finishing firewall forward
Peshtigo, WI
 
Pictures of an RV-9A cowl and baffle installation.

Ron,

Jump into my web site at page 60:

http://www.n2prise.org/rv9a060.htm

You must have the lower cowl fitting with the prop back plate before you begin cutting the baffles. Then continue on to page 62 & 63 and you will see how I started cutting the side plates first, then I went on to the rest of the baffle installation. I was just reading my text on page 63 and realized that I used the term "jigsaw puzzle" in my posting as well. Be sure and read everything through page 77 before you do anything. You will see where I screwed up but managed to recover without anything really hurt but my pride.

When you finally get to pages 73 & 74 you will see where I had to cut down the side baffles to clear the "ramps" on the inside of the upper cowl. There is a modification I did on page 73 that also follows something I have seen on another RV-9A that is already flying. You will also see where I abandoned the hinges used for securing of the upper cowl and changed over to screws like some others I have seen and you will see on my web site. Look at this page http://www.n2prise.org/TipSlide.htm to see photos where one builder used Van's hinges on his first RV-9A, then changed to screws on his second RV-9A.

Page 76 shows the fitting of the air seal fabric to the top edges of the baffles. Page 77 gets down to fitting the air seal fabric to the lower cowl air inlets. Although page 98 is about fitting the spinner shell to the prop and back plate, there are a couple of good pictures of the baffles on that page.

You will find little areas that need trimming as I did to get the cowl on and off easily, especially when you start putting on the nose gear leg fairings. I made some minor changes to the baffles as late as page 107.

Each airplane is different, due to the type of propeller installed. In my case, the constant speed prop sits very close to the engine and therefore the cowl is a bit shorter. I finally got the 1/4" clearance between the prop spinner back plate and the front of the cowl working smoothly with my last trims on the baffle parts. You will discover the method for putting the lower cowl on and off is quite a dance with the cowl, and then the air seal fabric on the air inlets for cooling and the filtered air box (FAB) to the carburetor.

Jerry K. Thorne
RV-9A 90622 N2PZ
www.n2prise.org
 
baffles

Ron: The responses you have received so far may include my suggestion, but I'll offer it anyway since it is something that I missed and wished that I had done. When you have figured out the assembly and are ready to start adding baffling material to seal the top take a look at some of the modifications to the left rear baffle. The one that includes the opening for the oil cooler. There is a very simple mod that will greatly simplify the cutting and tying of the baffle material. It basically makes the rear baffle a straight shot rather than having that funky turn. One good example is depicted on Dan Checkoways web site www.rvproject.com Good luck. Jack N489JE RV9A.
 
Baffle Priming???

Alright, another question to stir up problems...have people been priming the baffle parts? With the heat from the engine, and the airflow, is there really an issue with corrosion? I can see arguments both ways, so I wanted to throw it out there and get some peoples opinions!

Ron
RV-9A
 
Baffle priming

I've done it both ways - I wouldn't paint them again the the future. Too much trouble, never had any corrosion when I didn't, and you can't see them most of the time.

Pete
 
Don't be afraid to use some nutplates and screws in lieu of rivets so you can easily take pieces apart later. Especially where the side panels attach to the rear panels. I did this on my -6 and never regretted it!
 
add nutplates for extra baffles also

As far as nutplates go, you might want to think about putting some in front of cylinder #1 and around the intake for the oil cooler. I used the ones in front of #1 to put a small baffle to tune the air going over the engine. Really helped in balancing 1 and 3. The nutplates around the oil cooler opening are used for an adjustable block-off plate. My o-320 runs so cool that I have to block off most of the oil cooler air.

If you decide to box in the area behind #4 so that your baffles seals have a straight shot, try making it so that the rear baffle is boxed across the top. If you check out Dan's website he has it boxed across the bottom. If you put it across the top it will give you more area to install the oil cooler duct and it will raise the duct up away from the cylinder. It's a bit hard to discribe but go look at your baffles and you can figure it out.
 
sf3543 said:
Don't be afraid to use some nutplates and screws in lieu of rivets so you can easily take pieces apart later. Especially where the side panels attach to the rear panels. I did this on my -6 and never regretted it!
Click to expand...
That's a great idea! It sure would be easier to remove the baffles if they were able to be separated...I've already riveted the left side together, but that's definately an option for the right side.

So how often to the baffles get removed??
 
I didn't remove my baffles very often, but if you need to work on a cylinder, especially a rear cylinder, being able to remove the side panels with out taking off the rear panels is really nice. Don't forget, the rear panels are also attached to the front baffle pieces, so they are a real pain!
Even though you have riveted the one side together, I'd drill them out and put in nut plates. Make sure that the black material is installed in such a manner that the pieces are removeable.
I also liked the idea of putting nut plates on the oil cooler opening...wish I'd have thought of that. The same with the dam in front of #1 cyl...I experimented with dam sizes by duct taping them on the baffle and then finally riveted the final one on. It did make temps much more even between #1 & #2 cylinders.
Over 900 hours, I had quite a few instances, during maintenance, that I removed the side panels, so it was worth it to me.
Good luck.
 
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