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Stephen, The answer to one of your questions is easy. A fast cruise RPM should be 6000. Mazda did many instrumented runs and found that 6000 rpm was a sweet spot where the dynamics balanced perfectly. At 6000 there is almost no load on the bearings. The rotary would run at that RPM indefinitely. If you have more power at higher speeds you can use that for maximum speed. Those RPMs are eshaft RPMs not propeller. Bill Hi Guys
Thanks for all the feedback.
I think I didn’t explain my objective clearly enough.
Some questions:
1. Given I have variable pitch, what combination of MAP and RPM should I climb or cruise at? With fixed pitch I dont suppose you think in these terms.
So should I be Climbings at WOT & 7000rpm OR WOT & 6300rpm Best Power Mixture.
I think Lynn best understood my intention of trying to use the flight as a dyne - I didn’t realise the complexity of the relationship of mixture and timing at various settings, thanks Lynn.
I thought by keeping WOT and mixture constant I might ascertain a maximum efficiency combination for MAP/RPM.
I’d like a combination for max power. I’m thinking identified by higher fuel burn and IAS for the climb, and
a max efficiency/ecconomy combination for cruise identified by best miles per gallon.
I thought our Renesis with our modified OEM (shortened) manifold but no variable intake valves etc. would have a distinctive peak at ~6400-6600rpm.
2. I’m finding tuning the EC2 (objective being EC provides constant mixture across the flight envelope) is dependant on the combination I choose to tune it at.
Eg. Tune EC2 MCT for one MAP/RPM combination, say a cruise of 18” AND 5000 rpm, then the EC will not be able to provide a constant mixture if I then choose 18” at 6000rpm.
My EC2 has Tracy’s 8 table setup but fueling requirements given the extra permutations provided by the variable pitch prop (climbing that hill - which gear should I use - 3rd 4th or 5th??)
appears to stretch its inherent capabilities. So I want a plan for what MAP/RPM I will use and then adjust/tune the EC MCT for that combination.
Thanks again guys.
Steve Izett
all is nice if you fly that combination. If I then choose ab
> On 7 Aug 2020, at 6:16 am, lehanover lehanover@aol.com <flyrotary@lancaironline.net> wrote:
>
> Your thinking is correct. Control full throttle RPM with load. Then experiment always at that particular RPM until you have whatever data point you were after. Everything affects everything so it may be that (for example) advancing ignition timing at one RPM adds power but at another RPM reduces power. A rich mixture at one RPM may increase power but reduce power at another RPM. To recover even similar data on consecutive days is difficult. The SAE has some charts that produce a multiplier to account for density temperature and so on. Required to compare results day to day. It takes a long time to collect good data..........
>
> Lynn E. Hanover
>
>
>
> https://search.aol.com/aol/image?p=dyno+sheets+for+stock+rx-7+engines&s_it=img-ans&v_t=loki-keyword&fr=loki-keyword&imgurl=http%3A%2F%2Fwww.rx7club.com%2Fattachments%2Ftime-slips-dyno-128%2F346326d1243952257-anyone-have-stock-turbo-ii-dyno-graph-stock-s4-t2.jpg#id=19&iurl=http%3A%2F%2Fwww.rx7club.com%2Fattachments%2Ftime-slips-dyno-128%2F346326d1243952257-anyone-have-stock-turbo-ii-dyno-graph-stock-s4-t2.jpg&action=click
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