Mailing List flyrotary@lancaironline.net Message #66731
From: Charlie England ceengland7@gmail.com <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: MISTRAL
Date: Fri, 2 Apr 2021 09:07:27 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Well, my android phone returned the favor, refusing to display the link. Shows up on my computer, though.

Ah, yes; the self proclaimed Rotary God. ;-) I read through that thread many years ago. While the formula seems to work to extract power, I could never figure out why he was concerned with the number of degrees to get all 6 rotor faces through TDC. It seems to me that all that matters is the degrees from one lobe to the next, or from a lobe on one rotor to the next lobe on the other rotor. While a piston 4 stroke cylinder must go through 720 degrees for each intake cycle, the rotary 'cylinder' only needs to go through 360. 

 But I'm just an electron pusher by trade, so...

Charlie

On Fri, Apr 2, 2021 at 1:30 AM Le Roux Breytenbach breytenbachleroux@gmail.com <flyrotary@lancaironline.net> wrote:



Charlie sorry, yes you are right a phonecall got in the way and ate my mail 🙈🙈
Here is a link - of a RX7 forum

https://www.rx7club.com/general-rotary-tech-support-11/heres-how-figure-out-intake-runner-length-199788/

Scroll down and read only what you need.Very interesting how this guy calculate to determine the runner lenghts.
Further down on runner lenght calculations they talk about the Renesis motor runner lenght.
Yes this is for car use but there is a lot of info what we need for tuning the rotary on the “sweet spot” rpm.
The aquistic waves and speed of the intake air is very interesting

Regards

Sent from my iPhone
Le Roux Breytenbach

On 02 Apr 2021, at 00:52, Charlie England ceengland7@gmail.com <flyrotary@lancaironline.net> wrote:

Hey Le Roux,
I think your iphone ate your homework. ;-)
Part of the message seems to be missing.

Charlie

On 4/1/2021 4:35 PM, Le Roux Breytenbach breytenbachleroux@gmail.com wrote:
Check this thread about intake runner lenght,anwers on a lott of 13B engines and intake runner lenght and

Sent from my iPhone
Le Roux Breytenbach

On 01 Apr 2021, at 19:23, Charlie England ceengland7@gmail.com <flyrotary@lancaironline.net> wrote:

4 port or 6 port? It's been a long time since I had the manifold off the engine, but I *think* my 4 port engine has same size pri & sec ports. I know I used the same size tubing to make the manifold. I believe that the '3rdary' ports on a 6 port are smaller, but I think Steve Boese found that they don't do anything at our more reasonable rpms.

Charlie

On 4/1/2021 12:05 PM, Finn Lassen finn.lassen@verizon.net wrote:
Thanks Ed.

What I meant to say is that Tracy implied that secondary runners should have a larger diameter.

But I made them the same (inside diameter) as the holes in the block (30 mm).

Finn

On 4/1/2021 11:07 AM, eanderson@carolina.rr.com wrote:
Smaller dia may mean that airflow velocity is higher than in the primaries and since the secondary valves open at higher rpms, the higher airflow velocity may help stuff more air into the chamber give the shorter duration the port is open at higher rpm.  Just a WAG.

Ed

------ Original Message ------
From: "Finn Lassen finn.lassen@verizon.net" <flyrotary@lancaironline.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: 4/1/2021 8:48:31 AM
Subject: [FlyRotary] Re: MISTRAL

Tracy remarked on my secondary runners being smaller diameter than primaries and now I see the same here.

If I recall correctly, when I calculated the area of the secondaries vs the area of the primaries (in the engine block) I got smaller secondaries than primaries.

What gives?

Finn

On 3/31/2021 9:44 PM, Kelly Troyer keltro@gmail.com wrote:
Primary Runner length approximately........24 inches
Primary Runner "OD"  approximately.........1.40 inches
Secondary Runner length approximately.....24 inches
Secondary Runner "OD" approximately.......1.66 inches



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