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Baffle and oil cooler brace question

papamike

Well Known Member
I just started my baffles, and I have an issue with the CB-705B brace. I drilled the holes in the baffle from the oil cooler doubler, and now I'm supposed to drill the holes for the brace in the baffle.
The holes, if I have it oriented correctly, don't line up. Plus, the holes in the doubler are #30, the instructions say to drill these holes to #40.
Have I had my latest brain fart, or what?
20190122_171007.jpg

Here's a section of the plans:
20190122_171050.jpg
 
Hi Pete,
You may want to check on the forum for the mods performed to this cooler mount before you proceed any further. Generally the outer face is reinforced further, along with the join between the outer face and the aft face. A CRMo tube braces the inboard mounting bolts of the cooler back to the top of cylinder 4 (probably the most critical mod of all). Without these mods you could see cracking of the bracket within 100hrs. I'll post some photos when I get home tonight.
Tom
RV-7
 
Oil Cooler Doubler

I performed this same process last week and looking at your photo you seem to have moved the oil cooler doubler in a bit further than the plans advise.

I lined the doubler up 1/4 inch in from the edge as specified in the plans which meant that the hole I cut in the baffle virtually lined up with the inside surface of CB1004A.

Plus my holes in CB705B lined up with the holes transferred drilled from the oil cooler doubler.

In addition the holes you have drilled through the flange on CB1004A must be quite close to the radius on this part which could make it difficult for you to install the two anchor nuts.

Cheers
 
as far as the doubler holes being #30 instead of #40, I asked Van’s and they sent me the correct doubler. Had a batch mis-punched.

I waited until I had trimmed the baffles nearly to final height before I placed the cooler and trimmed that brace.
 
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I performed this same process last week and looking at your photo you seem to have moved the oil cooler doubler in a bit further than the plans advise.

I lined the doubler up 1/4 inch in from the edge as specified in the plans which meant that the hole I cut in the baffle virtually lined up with the inside surface of CB1004A.

Plus my holes in CB705B lined up with the holes transferred drilled from the oil cooler doubler.

In addition the holes you have drilled through the flange on CB1004A must be quite close to the radius on this part which could make it difficult for you to install the two anchor nuts.

Cheers
I used a reference dimension shown on OP27 that showed 3/8" from the edge of the doubler to the edge of CB705A. And in the photo, CB1004A is not necessarily secured in position yet. But I see what you're saying. So I guess I'll heed the advice I've been seeing several times to wait on the oil cooler until everything else is fitted.
 
Hi Pete,
You may want to check on the forum for the mods performed to this cooler mount before you proceed any further. Generally the outer face is reinforced further, along with the join between the outer face and the aft face. A CRMo tube braces the inboard mounting bolts of the cooler back to the top of cylinder 4 (probably the most critical mod of all). Without these mods you could see cracking of the bracket within 100hrs.
Tom
RV-7

+1 to this. I was not aware of the issue and had my baffle crack in the first 35 hrs. After repairing them as noted above and then having the oil cooler mounting flanges crack, I relocated the new oil cooler to the engine mount and all is good since. FWIW.

Al
 
Sorry for the delay getting these pics uploaded.
Please see below for the modifications. Most important is the brace back to the top of the #4 cylinder. I also build a custom bracket to support the inboard side. I didn't like the fact that it was only held in place by 2 of 3 bolt holes, so I tried to better distribute the load. You will also see that I used nut plates for the outboard bolts, because the reinforcement angle in the corner made fitting nuts and washers difficult. I raised mine by an inch per the procedure by others, but frankly I question the necessity with the IO-360M1B. I now operate with 1" taped off at the top, and I'm still on the cool side of normal.
Tom.
2927alx.jpg

2nkugg.jpg

lw3sz.jpg

29dephs.jpg
 
A brace to the cylinder is not the only way to stabilize the inboard joint of the oil cooler mount.
Addition of a beam made from fuselage "J" channel as shown has been completely satisfactory.
Reinforcement of outer corner joint is essentially nil in my case.

Approaching 800 hrs at time of this post. No cracks,

9744268474d855ddd1d000.jpg
 
Good call. Pretty neat solution. Any solution that stops flexing on that outer corner is key.

Tom.
 
+1 on nice work.... battleship strong? You can't be too strong with baffle mounted oil coolers. First they are heavy oil filed things with large hoses hanging off them. The OC integral flanges are weak... I have seen cracked baffles and cracked cooler flanges.

My solution as many is to fix mount the cooler and duct a hose... but the direct baffle method is pretty elegant if you take solutions like this.
 
Bill,

Was there a reason, besides aesthetics, to using flush rivets?

Marc,
You made me laugh at myself. It's obviously done to make the bird go faster....

First, the rivets are AD3s and Vans doesn't give you any round headed AD3s.
BUT, that was not the reason because I had plenty of the round head AD3 size rivets in stock from other sources.

Reasonable question and I have to reconstruct my thoughts from then.
Thinking back and also looking at the picture, I must have decided on flat heads because of the kinda' tight quarters for baffle seal material in the corner just above the oil cooler and just continued with flatheads all the way across.

Alternatively, I much prefer driving flat heads over round heads so it could have just been "automatic".
 
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