Behind Spinner Baffles: Cut and Seal?

Hi Guys,

Looked at the plans for 2 hours, trolled the site and internet now for an hour, but just don't get the right answer or picture, so I am going to ask...

What is the correct way to seal the inner baffles behind the spinner, where it transitions from the sides of the inlet to the back???

Heres the problem...the top cowl inlet ramps stop abruptly where they move inboard. If you cut the inboard baffles down to match the contour of the inboard inlet ramps, the baffles don't transition nicely to the top of the cowl (i.e. from the side of the inlet ramp to the top of the cowl)

Outboard no problem, but inboard??? I just don't get it??? Frustration and I don't have a RV nearby to check out!!

Do I need to cut the inner baffles down to the contour of the inlet ramps and then straight up like my blue line? The inlet ramps don't run all the way inboard to give you a nice contour as the outboard ones do??? (In the picture below the top has already been trimmed to match the cowl..)


If I do how do you seal it on the transition???

Pictures and or advice appreciated???

Thanks in advance...Kind Regards
Rudi

Don't

Hi Rudy,
Don't cut along your blue line. If you could imagine the forward piece of baffling laid out flat, it would have a semicircle shape. Then if you bent the sides forward, that's what it would look like. I'll try and upload two RV4 pictures.
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You just have to steadily work on this area to be sure that the rubber seals well here. A Formula 1 guy told me a long time ago that when air squirts out from behind the spinner in this area, it is like a vertical barrier and costs speed, so take your time here. Hope this helps,

Hi Rudy,
It's actually very simple ......just follow the contour of the inside of the cowl all the way around....including the ramps. It's no different for the forward section. Don't cut at your blue line or you'll have a gapping hole at your inside corner . Just make nice smooth 'rounded' cuts and again...remember to follow the contour of the inside of the cowl....whatever it takes. I like to lay the top cowl in place then, stick my hand in there with a sharpie and drag the marker along the inside of the cowl (leaving a scribe line on the baffles). Cut, then repeat till the cowl will drop all the way down where it's supposed to be. I have pics but I'm sure someone will post a few before I can dig mine out. I'll check back and post 'em if you still need them.

As a side bar....don't use those ugly pop rivets to install the baffle seals. #8 cad plated hardware is much more functional if/when you need to remove/repair the seals and are much more attractive. The hardware also will not put a dimple in your baffles like the pops will.

Rudi,
I'm at the same stage as you are and have just made the cut and fitted the seal. I'll post pics when I take them tomorrow. My cut line was somewhere between your blue line and the other pictures above. It's more of a blend than a step and I have a big overlap of the seal.
Jim Sharkey
PS - told you the baffles would be a pain in the bahooky!

gap seals

We are doing the exact same thing at this time. Do not cut your blue mark. Look carefully at your drawings and study how the airseals will form a gasket from the lower cowl air inlet, to the baffle floor, and then up the sides of the forward bulkhead, and around the inside of the top cowl. Cut the forward bulkhead to contour around the inside of the top cowl with 3/8 clearence gap. The airseals will fill this gap and seal against the cowl.

Hi Guys, thanks so far..

Some say it follows the top cowl all the way, some say it follows the inlet ramps. I am seriuosly worried about the transition. It seems if you just keep it high along the cowl, there would be a big gaping hole alongside the inlet ramp. If you cut it down along inlet ramp contour you have a step from the ramp to top of the cowl and another big gaping hole.

I must be stupid cuase I just don't get it PICTURES PLEASE!! Preferably a RV7

Dan's 7

Couple of photos from Dan's webpage.

http://www.rvproject.com/annual2005.html

Love that search function

I have since sealed the inboard nose baffles. I use the term "sealed" loosely....

dan said:

I have since sealed the inboard nose baffles. I use the term "sealed" loosely....

Click to expand...

Dan,
Did you notice any difference in cooling and/or performance when you added the extra sealing?
Jim Sharkey

jsharkey said:

Dan,
Did you notice any difference in cooling and/or performance when you added the extra sealing?
Jim Sharkey

Click to expand...

Zip. Nada.

RV6 Forward Baffle Seals

Rudi,
Here is what I ended up with on my "6". I still have to trim and stitch the "ears", and possibly dart in some areas to get the seal to seat better - but I'll leave that till just before first flight. Haven't a clue how it will work! The baffle profile generally follows the cowl and ramp profile all the way around.
Jim Sharkey

Here's a web link that may help. The one thing that I did to ensure a tight seal all the way around the spinner area was to extend the inlet ramps to make a smooth transition into the cowling.

That way, the baffle seal won't have any abrupt transitions as it makes its way from one ramp across the cowling to the other ramp.




http://www3.telus.net/aviation/flying/RV-9A/photos/Firewall_fwd/Firewall_fwd_photos.html

Some pictures

Hey Rudi,

Here are some pictures: http://websites.expercraft.com/PHVII/index.php?q=log_entry&log_id=8881 and beyond. Maybe it helps a bit, just don't dispair!
BTW: if I had to do it again I'd not use the plasticine clay trick to get the baffles fitted to the top cowl, but the paperclip trick or the sharpie-in wheel-trick. Good luck!

Hi Guys,

Thanks for the posts

Jim: OK now I get it, was paranoid about the gaping inboard hole of the inlet ramp ....I'm just suppose to use a lot of seal material on that corner, and get it as good as possible???


Vernon Little, I like your little mod, it will make the transition smoother and the seal better.

Rene: thank got some good tips from your photos.

Kind Regards
Rudi

RudiGreyling said:

I'm just suppose to use a lot of seal material on that corner, and get it as good as possible???

Click to expand...

Yup. Once you start flying you'll easily see visible chafing on the baffle seals where they meet (or don't meet) the cowling. Go from there...if you see a nice continuous "bead" of chafing, then you know you're getting a relatively decent seal. If you see gaps in the chafing areas, then you know, um, that you have gaps.

You can trim the baffle seals down a bit later if you find a lot of excess sticking "inside" the chafing area.