Come on ERA, don't give up on me. You wanted to call my work into question and I'm not seeing much rebuttal at this point.
No sweat, I'll just continue without you.
Step 1 was to measure the actual heights that matter to me. While coming up with a nice temp gradient with multiple data points would have been great for educating the world, I don't actually give a crap about the world's collective ignorance, so I'll only take data points that matter to me. We also need to remember that the actual temps don't really matter as we are only concerned with the temperature gradient, so let's not head down the road of humidity affecting readings.
The heights above tarmac that matter to me are the ram air inlet (
oil cooler opening), radiator duct (just in case I want to pull air from the top), just above the top of the radiator inlet (this is the air that will go into a normally positioned scoop, and finally at throttle body inlet height (this covers getting stupid and doing a snorkel inlet). Here is the heights above tarmac being measured with a laser level.
The final measurements work out to as follows:
Ram air: 7.4"
Radiator: 14.75"
Upper lip above the rad: 22"
Throttle body top: 29.75"
So the challenge now at hand is taking accurate temp measurements. My thought is that the biggest threat to accurate readings are:
Multiple measuring devices
Rapid measurement times
Radiant heat altering probe temps
Heat being conducted from objects contacting the temp probes
As a result of the above, I decided the fastest way to rapidly take multiple temperature readings from one device was to use a non contact thermometer. Lucky for me I already own a nice Raytec unit. The problem with non contact thermometers is that the target's reflectance can cause wide variations from actual target temperature. They get the most accurate readings from flat black surfaces. My solution was to make test coupons for the readings from .032 6061T6, and coat them in flat black on one side. To keep coating reflectance and thickness variances from influencing the outcome, each coupon was coated on one side with .002" thick cast flat black vinyl.
Next issue was insulating the coupons from any heat transfer though either radiant or unwanted conductive heat transfer, but also allowing maximum air contact for an accurate air temp reading. The solution was to make coupon mounts from 1" thick eps foam and coat that foam with foil to prevent radiant heat transfer.
First some hot wire action.
Then bonding on some foil.
Then cut into 4"x4" blocks.
To keep the test coupon from touching the foam, a toothpick (insulating wood) was epoxied to the back of each one, then it was positioned in the center of the foam mount .25" above the foam. To ensure consistency, the .25" measurement was maintained with shims until the epoxy was fully cured. The foam mounts were then positioned onto a rod and onto a base plate. Each mount could then be positioned where needed for a measurement.
Now that the test coupons are protect from radiant heat from the tarmac, I needed to protect them from the radiant heat of the sun, so I made a shade with cardboard and foil backing. Here is the entire assembly getting a proving run with the IR heater. Note that each foam mount is positioned so that the coupon is at the correct height, plus one coupon 1.25" above the tarmac.
Once all the test fixture proving was completed, it was time to take it out and do some real world testing.
Due to the varied reflectance of the tarmac, a test coupon was laid directly on the tarmac for temp sampling.
So ERA, you ready for some real test data, or will having your illusions shattered send you off the deep end?
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