I'm having a hard time
in this Florida heat, trying to do my first flight. With a
highspeed taxi run, (up to 55kts or so), will net my oil and
coolant above my warning limits. 240 oil pan, 230 coolant out.
The coolant inlet (44sq") is huge with the idea that down
the road I'd go turbo. The rad is from a dodge truck 19 x 24 x
1 = 454sq", with a wedge shape diffuser. Right now it just
exits the back of the cowl, no cowl flaps or sub cowl
installed yet.
The oil
inlet is a lot smaller (~12.5sq"), going to a 2.5" scat
hose, then to a trumpet shape which leads into a wedge. The
oil rad is 9 x 11 x 2 = 198sq" from cx racing. For the
outlet, I have a big box to collect the hot/expanded air,
then neck it back down to 2.5" exit. Tomorrow I'll try
another taxi test, with the outlet box completely removed and
dumping into the cowl.
To find out if my prop is doing anything with airflow into
the inlets, used a tube of water and found around 2200 static
rpm, it raised the water about 4inches in the oil duct. I
think that equals around ~55kts. I thought the prop would of
cooled down the rads a lot more, but I guess I have bad duct
designs. Maybe move them closer to the blade? Looking at the
picture, the oil is on the left with all the green tape. I
tried to make the opening bigger with foam, didn't see a real
difference. Being on the bottom of the cowl and to the left,
it doesn't get the rotating air from the blades as much.
I know high speed taxi tests in this Florida heat, is probably
the worst case scenario. Depending how the morning goes, we
might just fly the plane and get some speed into her nose. See
at what speed the temperatures stabilize and start to cool
down.
- Matt Boiteau