Our cooling is generally fine, but on hot days when we stay in the pattern, the CHT’s get warmer than I would like. Luckily we know Terry Schubert, of CSA fame, and he’s just the guy to give us some tips. So, we setup for him to come down with some aquarium hose, air stones, and we hooked them up to our engine cooling plenum, top and bottom… and went out for some test runs. We took a bunch of data at 3,000′ pressure altitude (altimeter set to 29.92″) to see how much pressure recovery we’re getting from our NACAs. Ours is not as good as you might see on some well designed EZs, but for for reference here’s our data.
|
OAT
|
BARO
|
| 76F | 30.16 |
| KIAS |
delta P
in WC |
| 100 | .9″ |
| 110 | 1.1″ |
| 120 | 1.3″ |
| 130 | 2.8″ |
| 140 | 3.2″ |
| 150 | 3.6″ |
Basically it’s telling me that we should cruise climb at 130 because we get much better cooling there than even at 120. Yes, we won’t get the performance of Vy, but a cool engine is a happy engine. I won’t be obsessing over upgrades, but we did identify several places where we’re surely losing cooling air to leaks, and I’ll begin slowly addressing them and checking these numbers again to see if we’re making improvements. Some other captured data:
| MT prop |
||||
| IAS |
100 | 110 | 120 | 130 |
| OAT |
76 | 76 | 76 | 76 |
| CHT1 |
357 | 355 | 344 | 341 |
| CHT2 | 377 | 356 | 365 | 362 |
| CHT3 | 349 | 325 | 336 | 335 |
| CHT4 | 348 | 333 | 342 | 336 |
| CHT5 | 384 | 355 | 371 | 370 |
| CHT6 | 400 | 385 | 396 | 384 |
| EGT1 | 1156 | 1132 | 1145 | 1147 |
| EGT2 | 1184 | 1193 | 1182 | 1174 |
| EGT3 | 1169 | 1157 | 1156 | 1154 |
| EGT4 | 1234 | 1228 | 12321 | 1212 |
| EGT5 | 1159 | 1163 | 1142 | 1148 |
| EGT6 | 1195 | 1191 | 1187 | 1179 |
“The Legend’ Terry Schubert |
The potentate’s magic carpet |
We also hooked up to the rear oil cooler inlet and outlet but got no data… pressure side of the oil cooler |
Low pressure side of the Oil Cooler |
This is the plenum, pressure side connection |
And the low pressure, outlet, side of the plenum |
Posted By: Brett FerrellSaturday May 31st, 2014 at 1:34 PM
Categories: Cooling Flight Testing Tags: Building Cooling Fuselage
[…] At any event, he was good enough to get some aquarium hose and air stones and fly down to help me figure out where we should hook them up. Then he gave me his favorite test sheet and flight test parameters, and Beth and I went out and flew the test. We really should’ve done it earlier in the morning when it would’ve been easier to hold tight altitudes and speeds, but at least we got some baseline data that we can compare to in the future to see if our changes are helping or hurting. Check out the detailed page here. […]