Steve

I suspect it’s #2. Steve B’s email has a wealth of information and points to airflow. To prove it layup a quick but reasonable shaped duct and test it with the cowl off. I would start with a 28 sq or large inlet. 30% of the core face would be a good place to start testing.

I’ve only seen Tracy takeoff in the RV8 once. But he was not using anywhere near full throttle. He did a lot of work on the inlets but I’m not sure he can use all 300HP in the summer.  

Bobby



Sent from my iPad

> On Dec 28, 2017, at 5:13 PM, Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
>
> Hi Guys
>
> Thanks for the replies
>
> Our water inlet is small (Standard Glasair) - modelled of Tracy’s RV8 20b
> I understood he had a round right cheek inlet of 5.25” giving him 22 in^2 to his water rad for 300hp in Florida temps.
> For the two rotor -> 2/3rd of 22 is <15. We have >16 for <200hp
>
> My concern is the delta T’s.
> Yesterday at 1800rpm I was seeing 12F across oil and 6F across the water. Previously I’d seen this as high as 18F and 9F not sure why so low yesterday.
> What do others see on the ground at idle?
> Does anyone have good pressure data on the ground. Idle and power settings?
>
> Are these low due to:
> 1. Water flow due to cooling system design or air trapped.
> 2. Air flow due to small inlet, compounded by a prop that doesn’t have much blade near the spinner.
>
> I’ll look at some further baffling of the Rad to exit but cant see this helping at idle air speeds unless I duct the exit low pressure direct to the back of the core.
>
> I’ll send further photos
> Thanks
> Steve
>
> Steve<3.JPG>
> <Cowl exit.jpg>