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Old 01-13-2017, 10:52 AM
j-red j-red is offline
Join Date: Dec 2015
Location: Lewes, DE
Posts: 365
Default First Engine Run

This post is almost a duplicate of the one in my builders log forum, but I thought I'd post it here given the many who responded to the engine build video who might be curious but who might not lurk there often.

With the prospect of an unusually warm (70 degree) January day, the time seemed right to try to get a first run in on the rebuilt o-360. I attached a mechanical oil pressure guage in addition to the one linked to the GRT EIS so that I could watch pressure build as the prop was pulled through to pre-oil the engine. Satisfied that oil was flowing freely, the top spark plugs were installed. Then, after doing yet another thorough inspection of all hoses, wires, and cables forward of the firewall, the moment of truth arrived.

She started in about 8 revolutions. Oil Pressure on the mechanical guage is good, nice smooth idle and no emergency signals from my observers!

Fuel Pressure with electric pump on: around 6.5psi. engine pump only: stays about the same.

Oil Temp Climbing appropriately

Fuel flow at idle showing 2 gph or so. Is that right? It later climed to 9gph at 1700 rpm, so I conclude "probably."

CHT's and EGT's take some time to register, but appear pretty even with the exception of the #1 CHT. It registers 50-100 degrees cooler than the others for most of the run. Now, it could be the sensor, it could be the fact that the cowl was off and that cylinder was getting more prop blast, or it could be a problem. Opinions would be appreciated. EGT's were about the same as all the other cylinders. More testing will need to be done with another sensor and with the cowl on...

Now, most of my experience is behind a small 6-cylinder corvair conversion, so "smooth" is a relative term, but my observers have two lifetimes of aircraft engine experience and seem to think things are running smoothly.

The test included both starting and running on the E/I, the Impulse mag, and then both together. All starts were quick and clean. Engine was run up to about 1800 rpm. Too much beyond that took too much brake pressure to hold.

I need to adjust the mixture slightly. Don't seem to get much if any RPM rise when leaning either at higher or idle rpm's which should be the case prior to cutting out, thus proving that the mixture is, indeed, rich enough for appropriate engine cooling.

A final, brief, taxi test concluded the session. It was basically just a return to the hanger, and can be seen in the following video.
Rebuilt RV-6A N94CR
RV-8 N803DR completed, flying.
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Old 01-13-2017, 12:15 PM
YellowJacket RV9 YellowJacket RV9 is offline
Join Date: Oct 2012
Location: Clearwater, FL KCLW
Posts: 1,333

Congratulations - I know that was a big moment for me. About a few of your thoughts:

9GPM at 1700 static RPM sounds a bit high - but probably just need to calibrate your fuel flow sensor, which really requires burning though a few known quantities of fuel to nail down.

I wouldn't worry at all about #1 CHT, especially if EGT's are all in line. Without cowling and baffles in place and real air flow, you won't really know how well your cooling setup is working. Do everything you can now to make your baffling perfect.

Don't go adjusting the mixture unless the engine is completely warmed up, it will change - which may take longer than is advisable for a new engine before break-in. Adjusting the mixture at the carb will have nothing to do with cooling, as it only adjusts the IDLE mixture - the rest of the time the red knob controls mixture. Your max fuel flow will depend on the size of jet installed in your carb. Do make sure your mixture and throttle levers go all the way to the stops.

Chris Johnson
RV-9A - Done(ish) 4/5/16! Flying 4/7/16
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Old 01-13-2017, 02:11 PM
Electrogunner Electrogunner is offline
Join Date: Aug 2016
Location: Quarryville ,pa
Posts: 605

That is awesome!! I'm actually at ups freight right now picking up my IO540. Needs OH but I can't wait to fire it on airframe for the first time. I have a long way to go. Good luck with the rest of build but you're almost done.
RV10 N821BS coming soon
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