flyrotary@lancaironline.net Mailing List Archive

Hi Finn

I smiled reading your question about ‘is that 10 or 20 inches'. I remember thinking exactly the same thing!

I think the difference between the two levels is the correct pressure. But I’m working with a pentium#1 cluster of neutrons!

All the best with the experimenting.

I found a significant fault in my experimenting on Saturday.

I’ve been fine tuning the H2O diffuser shape using the differential transducers across the face.

Then made new exits for the cowl and flight tested. The temps were fantastic! Peaked at 90C.

Then realised that I had some flights back disconnected the front gear door closing mechanism!

I’ve flown the last few test flights thinking the gear door was closed when it was open.

I reconnected it and did a flight test. The hottest day I had flown - OAT of ~37C.

Both Oil and H2O temps quickly hit 110C.

On reviewing the log data after the flight, delta pressures across the H2O rad plummeted to less than half compared with the same airspeed and when I unknowingly had the front gear door open.

Ive got a real problem with my exit air! So reviewing he cowl exits again.

In relation to EC2 MCT programming. Ive done some work and on the last flight it was so much better and hands off.

I did play with the MCT entries in those addresses used at startup and early idle while warming up. Addresses 0-31

I added 30 points of enrichment. The result was that it started more quickly and idled better. Good outcome.

Cheers

Steve Izett

On 21 Feb 2022, at 1:34 am, Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net> wrote:
Finally got around to making coolant flow "sensors". (Used existing 3/4" cu pipe with wells for temperature sensors. Maybe a bad idea because of the restriction may not make it true 0.75" ID.)

Trying to calibrate pressure sensors.
Have a hose with water. Connect to vacuum and pressure ports of sensor when water is level. When I raise one end of the hose to get a 20" difference between the two water levels, is that 10" or 20" H2O?

Yesterday I filled a 5 gal bucket through the sensors, timing it to 9 gal/min. Pressure readout indicated what I had previously gotten as 35.25" H2O.
Something is obviously wrong. Perhaps the 35.25" H2O was really half of that?

Moving on. Trying to make a formula to convert inH2O to Gal/min.
h_w _{(in H2O)} = 0.186 (v_fpm / 60)²� � where v_fpm = velocity (ft/min).
Vfpm = 60 * Sqrt(Hw / 0.186)
231 cuIn / gallon.
Area of 3/4" pipe: 0.44 sq in.
231/0.44 = 525" or 44 feet/min for 1 Gal/min flow.
So gal/min = 60 * Sqrt(Hw / 0.186) / 44
60 * Sqrt(20" / 0.186) / 44 ~ 13.6 gal/min. Close to Steve's 16 gal/min through 0.8" pipe.

Anyone seeing a mistake here?

Need to repeat my filling 5 gal bucket through sensors test, but need to get my pressure sensor calibration right first.

Finn

On 8/21/2021 12:15 PM, Steven W. Boese SBoese@uwyo.edu wrote:
Finn,

20" of water column corresponded to 16 gal/min through a 0.8" dia tube.� Coolant delta T is based on measurements in my plane. Typically, I see about 10 deg F delta T at a cruise power setting.

If I remember correctly, Bill Shertz made water pump flow rate measurements with a system he set up for this purpose.

Steve Boese��
From: Rotary motors in aircraft <flyrotary@lancaironline.net> on behalf of Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net>
Sent: Saturday, August 21, 2021 6:04 AM
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: Coolant flow sensors
�
Thank you Steve. Exactly what I need. I can make those.

What were the approximate pressures?

On a related note, what is the 15F coolant temp deltas you mention based on?
35 gpm coolant flow cooling 180 HP?

I keep wondering where the 35 gpm comes from.

Mainly by reducing oil cooler exit air area, I'm now down to 200F @130 mph @ about 4,000' density altitude and 70F OAT. Can climb at full power to about 1,500' on a 85F day (keeping speed at 110-120 mph). Only small incremental improvements so far.. Looking for that magic change that will lower that to 180F.

After working with air flow, I think I'll now circle back to coolant flow. Coolant delta over right rad still higher than left rad. Am thinking of hooking up a garden hose to rad inputs and see how quickly 5 gal buckets will fill up from each rad output But 35 gpm is a lot more than a garde
n hose can supply?

But flow sensors should give better real world results..

Finn
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