Mailing List flyrotary@lancaironline.net Message #66536
From: Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Renesis primary iintake ports circumerence
Date: Tue, 22 Dec 2020 11:58:58 +0800
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Hi Finn

Yes. That’s why I ended up with the 32mm ID Primaries. It was the best I could find and when squashed, that tube fit the primary intake shape pretty well.
I tried to keep the dynamic effects of the OEM manifold (shortened to lift peak torque and dynamics up to 6000 and 7200rpm), but if I was to rebuild, I think I would just have clean runners as Tracy opted for into a plennum chamber.
Tracy wrote that his 4 port was producing 215hp @ ~21g/hr from memory which is better than we are seeing.

Steve


On 22 Dec 2020, at 10:45 am, Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net> wrote:

Thanks Steve.

1/8" wall is a bit too heavy for me. 1 mm or 0.04" would be more to my liking.

Looking at at manifold drawing it looks like I need 33.5 mm (1.319") ID tubing.

Seems the closest I can get is 1.5" OD with 0.049" wall. 35.6mm ID.

What I really need is 1-3/8" OD and 0.028" wall but have not been able to source that.

I might end up just wrapping existing runners with more fiberglass/epoxy.

Finn


On 12/21/2020 9:11 PM, Stephen Izett stephen.izett@gmail.com wrote:
Hi Finn

My notes show (from measurements of hem intake) that the Renesis 4 port primary and secondary runners are 30mm diameter.
I used the original secondary runners after cutting and turning the manifold ~180 degrees.
I used 32mm ID aluminium tube with a 3mm wall thickness for the Primaries.

Steve Izett





On 22 Dec 2020, at 9:56 am, Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net> wrote:

Couldn't understand why it kept "idling" at higher and higher RPMs (3,500 at the end and had to cut fuel and turn off the EC3 to shut it down).

I had made the primary runners from the plenum to the intake ports with 0.016 alum rolled and covered with fiberglass and epoxy on the outside. Seemed a simple way to go from oval at the port/manifold to round in the plenum.

Obviously I completely underestimated the amount of vacuum that the engine can pull or pump. Perhaps if I had added multiple layers of fiberglass ...

So I need to use thicker tubing or pipe.

Anyone here that can remember the size of tubing they used? (OD/ID and or thickness)

Finn





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