Mailing List flyrotary@lancaironline.net Message #66729
From: Le Roux Breytenbach breytenbachleroux@gmail.com <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: MISTRAL
Date: Fri, 2 Apr 2021 08:26:28 +0200
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Charlie sorry, yes you are right a phonecall got in the way and ate my mail 🙈🙈
Here is a link - of a RX7 forum
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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