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prkaye

Well Known Member
I'm already baffled by the baffle plans. At the very beginning, on page OP44-3, Step 3 says "Position the CB-705B Oil Cooler Brace on the CB-705A Cylinder 4 Aft Baffle per plans page OP-27A....".
On Page OP-27A, they don't actually give you dimensions. They don't tell you where exactly the FF-709 sits, so you don't even know where to cut that big hole. Note 3 on the drawing says that you should "fit cowling and rubber air seal material in this area prior to mounting the oil cooler. For the greatest efficiency mount the oil cooler as high as possible".
We have chicken and egg scenario here. This is the first assembly in the baffle plans, so I can hardly do what Note 3 asks of me. But without having done that, I have no reference for positioning the CB-705B Oil Cooler Brace.
What the heck?
 
Baffling

Phil,
I would hold off on positioning the oil cooler for now. I think that you can Cleco together the baffles and make the spacer that fits between the left side and left rear baffle now, trim the tops of the baffles to fit under the cowl (I like the paper-clip-as-a-gauge method), then worry about positioning the oil cooler after the baffles have been trimmed. I had to re-order some parts as I had tried to place the cooler mount early on.
Good luck. I am seriously considering a drive to Aurora in the morning to pick up more parts. I am none too happy with my front ramps.
 
prkaye said:
We have chicken and egg scenario here. This is the first assembly in the baffle plans, so I can hardly do what Note 3 asks of me. But without having done that, I have no reference for positioning the CB-705B Oil Cooler Brace.
What the heck?
Click to expand...

Phil, also watch the cooler inboard (middle) mount. You can not go too high because it may not clear engine mount.

vbpiper said:
I am none too happy with my front ramps.
Click to expand...

I am not happy with mine as well but I didn't bend them completely yet.
Do you have any refs (websites) you were using doing ramps?
 
I second (or third) the advice to not cut the hole fr the oil cooler until after you have a chance to see how the upper cowl fits. I cut the hole early and just barely ended up with enough room. Cleco the back and side together baffle, in place, then place the top cowl on, check the fit, trim the material, refit, retrim, etc. and THEN you can tell where to make the cutout.

But, yeah, I have found the plans difficult to follow in a few places.
 
baffles

Phil,
Probably the easiest way to get out of the chicken/egg deal is to fit your cowl first. Get the cowl where you want it in relationship to the spinner. Take the top cowl off and place the rear baffles and #3 & #4 side baffles clecoed together and screw the sides to the #3 and #4. Cut tops off the baffles till you have the top cowl fitting correctly with the lower cowl, allowing correct distance from baffle to top cowl. Once this is done then you can determine how much to cut off the brace and then where to place the oil cooler. I did not do it this way, tried to follow the plans, and it was a PITA to cut the baffles down with the brace on the rear baffle. Don't rivet anything together until the rear and sides are cut to correct height, very difficult to get height correct especially in the corners.
Hope that this helped.
Mike H 9A/8A
 
Phil, you're moving into a new phase. Some mental adjustment is necessary.

New builders tend to move along well through basic airframe construction. Everybody's wing and tail and fuselage is the same; it is easy for the kit manufacturer to write detailed instructions and supply dimensioned diagrams. Everything is 1-2-3, A-B-C. Great progress is apparent, big shiny parts are everywhere, and the world spins on greased grooves.

Then they hit the variables.

Different engines, different props, different exhausts, coolers, fuel delivery and ignitions. A vast array of avionics choices, a million wiring variations. Fiberglass fitting and fabrication, then finish and paint, with 20 ways to do each. The kit supplier simply can't cover them all with the sort of detail found in basic airframe construction. Instructions become guides to general concepts and mere clues to methods. You must transition from "assembler" to "builder" by visualizing the desired result for your package and working out a path to get there. More or less you create your own instructions, a highly edited version of the ones that came in the box. Consider the fundamental principles of craftsmanship for the area of interest (avionics, wiring, paint, etc), not the necessarily generalized instructions supplied by vendors.

Some do it with seamless ease, others struggle, and I have no idea where you fall in the range. I just want you to know you're arrived at a milestone of sorts, and things will be a bit different from here to first flight.
 
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Making steady progress... For the cylinder 1 and 2 side baffles, it looks like I'll have to chop a good 1.5 inches off the forward end of these to get them to fit into the lower cowl. Is this typical? The plans don't mention cutting the forward edge of these back.
The plans say to bend these inboard to clear the cowl, but even doing this they still need almost 1.5 inches chopped off the front.
 
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You will be cutting off LOTS o' metal Phil. The top cowl has to fit on, ergo, you have to keep trimming.....

Paul
 
baffles

Phil,
Actually the plans do show cutting off the front of the forward baffles. Look at the plans again and you will see the hatched area to be removed. That is very conservative. I had to trim bunches off of mine to get it to fit. As Dan and others pointed out, the instructions are only a guide to get you going in the right direction. I've had to alter my 0-320 baffles for my 0-290D considerably and make many 'innovative' changes. Just do what it takes to make the baffles work. You'll get there. I finally did.
Mike H 9A/8A
 
OK, thanks guys! You've removed my fear of hacking up the Baffles. Hope to have a decent preliminary fit done this weekend.
 
Well, I finally (after 8 hours or so of iterative trimming) got my baffles trimmed down so I have a near-perfect 3/8" gap between baffles and upper cowl (used the paperclip trick).
Now I'm starting to put the pieces together... do you guys think Blind Rivets would be OK for a lot of the baffle stuff? Some of those rivets are hard to reach with a squeezer, because of the odd shapes of the peices. My intuition is that there should be very little stress on these, so blind rivets should be fine, but wonder whether severe vibration poses and additional consideration when it comes to using blind rivets.
 
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