N254MR

In the photos below, the left side ignition coil's cooling "blast" tube is getting epoxied into place. The first photo shows an overhead view of the tube. The little blue tube of Permatex is keeping a little side pressure on the tube while the epoxy sets up. I'll have to reset the location of the wire bundle just right of the little blue Permatex tube a little to avoid vibration contact between it and the blast tube. The bottom end of the tube is beveled to allow the tube to snuggle up close to the coil. Jabiru's standard instructions for this step call for extending the tube inside the cylinder baffle about 1.5", presumably to pick up more freely flowing air than is present right at the back face of the cylinder baffle. However, in this case, there is just not enough room for the tube to go in that far without hitting the cylinder head, so the inside end of the tube is flared, and epoxy will be added to the inside tube-to-baffle junction when the outside cures. The second photo gives a side view.

Side view:

After trimming and rounding the forward bottom flange corners of the oil cooler, it was installed on the engine sump for the first time today. Installation took quite awhile [Ed.: What doesn't?] with hemostat, etc. After measuring vis-a-vis the nose bowl for precise location of the cooler baffle to the nose bowl - which can't be done until an intake hole about 1" X 4" in the nose bowl is completed -- the cooler will probably have to come off at least one more time for construction of its small intake baffle. In the meantime, I'll make the hoses.

A profile view of the installed oil cooler from the right side. A digital level on a straight edge between the firewall and rear flange of the cooler confirmed the cooler is a smidge lower than the firewall.

The oil sump fin "plenum" air duct, which has been coated with Everbrite, has been installed. In the first of three photos below, you can see the installed duct, held on by the same horizontal bolts that connect the oil cooler top brackets to the fins. The top flange, in the upper left, will connect to a piece of milled foam which will go between the air duct's inlet in the nose bowl just below the prop spinner. At the lower center-right, you can see another short flange that's bent down, at the outlet of the duct. A little firewall sealant will be added to the side flange corners at the bend in the middle of the duct, to minimize air leaks. The top hole will be secured with a #8 machine screw and Loctite, assembled into the original factory-built threaded holes.

The following bottom up view shows the four slots for access to the MS21042 nuts on the side bolts that hold the upper oil cooler brackets, and this duct, to the fins. The access holes will be covered with some aluminum tape before the oil cooler is mounted, to keep the duct from leaking. It took nearly two hours with a hemostat and a specially thin-ground mini-open end wrench, to do those nuts.

Last, the opposite top angle view of the installed oil sump fin air duct and the top oil cooler brackets. The top hole on this side of the duct will also be secured with a #8 machine screw in the factory-built threaded hole. That screw will also hold an Adel clamp securing the oil cooler hose going to the AN6 adapter on this side of the cooler.

The new Magnecor 8mm Electrosports 80 sparkplug wires arrived, and I couldn't keep from installing them. As shown below, the new, longer wires allow clean routing up and over the B&C SD20S auxiliary alternator, and away from the AeroCarb linkages and control cables. The lengths were perfect, except for one that was about 2" short. I was able to quickly look in the plug wire spreadsheet for the next longest wire, and sure enough, it was about 2" longer, and had more length than needed over its run. So the one slightly short cable was easily swapped for the next longest one, and all was well. An added bonus is the high quality connectors on each end, which snap onto the distributor and plugs much more securely than the stock wires. Even better, this item can be checked off the task list! 

Except for a coat of Everbrite, the oil sump fin plenum is completed. Below is a view of it from the bottom. The four slots will allow minimal access to the nuts which hold the upper oil cooler mounting brackets -- inside the slots between the fins. Because this is essentially an air duct, the four access slots will be covered with aluminum tape after the nuts are installed, and before the bottom oil cooler mount brackets are attached to the uppers.

A busy day. Just finished the last step of machining needed for the oil cooler mounting by back drilling holes for the upper mount brackets back into the oil sump fins, as seen below, looking back at the right side fins on the bottom of the engine. (No two ways about it, drilling through the oil sump fins is a bit nerve wracking.) Although it's not visible here, the top, inside edge of the upper bracket had to be radiused a bit to fit snugly into the top corner of the outer fin casting. Notice that the hole, which ends up at a fairly large 3/16" dia. for AN3-5A bolts, has to go through two fins. Even though the nut will go in the first slot between fins, the threaded end of the bolt is too long to end within the first slot, and must extend into the second fin. Vertical placement is critical. The holes have to be high enough to maintain material edge distances on the bottom, but low enough that an MS21042L nut will fit inside the slot without hitting the bottom of the sump. Anyway, except for a little deburring and cleanup, the oil cooler mount is now complete. After the sump fin "slot plenum" is drilled to fit between the upper brackets and the fins, the whole shebang will be bolted on, so I'll soon be able to check off two more items on the task list. Yea!

With help from neighbor Mike, the cowl construction begins with careful positioning of the nosebowl, done with layers of foam under the top edge, then fabrication of the tapered side channel frames and dimpling the holes at the fuselage ends, which will have interior nutplates for #8 countersunk SS machine screws. We were able to confirm adequate clearances for the oil cooler (whew!) so it's time now to drill the sump fins to attach the cooler mount brackets. A circle for the rear of the nose bowl was marked and is ready for trimming, but final fore and aft positioning of the nosebowl will await arrival of the propellor spinner and its backplate, which should be here in two days. It's very exciting to have arrived at this stage.

Here's an earlier shot from the right side, showing that the bottom of the nose bowl is already below the bottom of the firewall. Very little if any further drop will be needed for the air outlet "ramp".

In addition to briefly attending the annual Wooden Boat Festival in Port Townsend, I've been making progress on the mount for the Positech P20002C oil cooler today. It's about 80% done now, shown here just held in temporary alignment with some stray commercial bolts. Below you can see how the two bottom angle brackets sandwich the top flanges of the oil cooler, held together with some 1/4" bolts, and with some aluminum tubing to act as crush prevention spacers. The angle brackets on top have rectangular cutouts for access to the hose connections.

Fortunately, I didn't have to design all of this with my own limited cognitive horsepower. Instead, I'm using an excellent example design from US Jabiru. The operations still left to do are (1) backdrilling the holes in the top brackets through the lower brackets, (2) drilling horizontal holes through the top brackets and the oil sump fins, and (3) building a small rubber baffle for the intake side.

The right side engine baffle has been mounted. There's more to be done, such as the ignition coil cooling tubes, joining the split front intake "snouts", and building the half height air dams inside each intake, however, those items can wait a bit. More important at the moment are the oil sump fin cooling plenum, and mounting the oil cooler. When those are done, the cowl work can begin.

With all the FWF wiring done, a few tasks remain before building the cowl can begin. First is completing and mounting the fiberglass engine cooling baffles. The outer edges of the baffles are secured by three of the valve cover bolts. Although the factory examples show the bolts tightened right down onto fiberglass, not surprisingly, there have been several reports of damaged baffles from the turning torque. So like others, I added aluminum reinforcing strips to each bolt connection. They have a smaller aluminum piece inside to act as a washer, and the two aluminum pieces are riveted together with the low profile dome rivet head inside to minimize air flow interference.

There's more to do on these, including the front air "dam" to close off half the height, forcing incoming air to go high, and installation of the rear cooling tube outlets to cool the ignition coils.