N828CB kit 1175 O-540

[Xctreker]

Inspirational! Do you have a posting of the work in progress?

[swpilot3]

Thanks!! Yeah, you can check out my build log at http://azbearhawk.com

[22LD]

Looks great, Bobby. Good luck with the DAR visit today. Gary's and awesome DAR. Looking forward to seeing your plane.

[swpilot3]

Hey Larry! Yes, Gary was great!!! An absolutely pleasure to work with. I'm glad he braved the heat to come all the way down the valley.

Gary had a few recommendations but other than that, no big sqawks. After he explained all the operating limitations he left to drive home and we went to work putting all the panels and cowl back on.

I waited until the wind died down a bit and took my new Bearhawk for a test flight. She did great! Leapt off the ground before I got to full power. CHTs were mighty high, but started to calm down after 15 minutes. I'm so surprised that it flew hands off without a heavy wing. I did a few turns and some slow flight then back to land. Super stable and she landed great.

I'm waking up early in the morning when it's cool... or relatively cool (80)... to do the same test flight again.

I'll let you guys know more as I progress through the 40 hours.

[Bdflies]

Congratulations!! Very exciting times ahead!

Bill

[Mark Goldberg]

Congratulations on getting signed off and first flight Bobby. Very exciting. Mark

[rv8bldr]

Pictures/videos or it didn't happen

[swpilot3]

Hahaha! That's what everyone is saying! So, here's a video proof that it happened!

[Bdflies]

Might not be real.... That's WAY too professional!

Bill

[swpilot3]

Ha!! Thanks Bill!

[PaulSA]

Awesome! Congratulations......

[mswain]

Beautiful plane, congrats!

[svyolo]

Congrats. Fantastic looking plane.

[22LD]

Very cool video! Congrats!

[JimParker256]

Congratulations on a fantastic accomplishment. Very cool video! I loved how you pulled off the "NASCAR doughnut" there at the end... Sounds like a very supportive family was watching proudly.

[swpilot3]

Thanks guys! Yeah, I did have a very supportive crew!

So here's an update at the 5 hr mark. It's been hot here in AZ. Even at sunrise it's 85. Like most people with a new Bearhawk running a new O-540, I have hot CHTs. After talking with Mark Goldberg, I enlarged my cowl exit and spent a lot of time making sure the baffling is perfect.

However, I still had VERY hot CHTs. As soon as I climb through 1000 AGL, the CHTs were soaring past 450. So I pulled the power back to keep everything within limits. That ended up being 14" just to keep it under 475. Unacceptable. However, after talking with Schu it dawned on me that my heater box just dumps 2" of air out the side when closed. Also I've heard that the 4" scat tubing going to my oil cooler is also using A LOT of air that isn't cooling the cylinders.

So, I completely blocked the 2" heater tube and partially blocked the 4" oil cooler tube. Voila! That did it. I was able to climb to altitude and cruise at 65% power with the CHTs at 400 and the oil around 190. From what I've read, that's pretty reasonable for a fairly new engine in the summer here in AZ.

The bad part is that my EarthX battery didn't survive very well in the hot temps. Its on the engine side of the firewall. The fault light illuminated and the case bulged. They're sending me a new one. I'm going to wrap it in a heat shield and put a temp probe there to monitor the temp.

[rodsmith]

There is a butterfly valve available for the 4" oil cooler supply which I will install. Very discouraging to hear about the EarthX issue. I was afraid that the 140 deg operating/158 storage limit was not enough to survive on the firewall. For in cabin use you are supposed to use the vented version which is a $100 more. Your heat issues seem to validate my decision to use cowl flaps, even though they added at least 3 months to the build. Congratulations on a great airplane!

[swpilot3]

I like the butterfly valve idea on the oil cooler air supply. I might retrofit mine.

As for the EarthX, they've been great to work with. They said that the case bulging is just the plastic case warping, but it might have squeezed one of the cells causing the fault. I asked about how dangerous this was and they said not at all. They really didn't seem worried about it... safety wise. However, hot batteries warping has become enough of an issue that they're coming out with a thermal shielded battery box. It's in production now but the launch of it will miss Oshkosh by 2 weeks. I'm getting one.

I had originally decided not to do cowl flaps because so many Bearhawks are flying just fine without them. I kinda wish I had done it though.