Add Peripheral Exhaust Port To Renesis

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Lendo

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Sorry Dwalker I should have said small PP intake port with side ports. What you seem to be missing is the side intake and exhaust ports are restrictive due to the nature of the ports themselves, they may well be oversized for this very reason; however PP provide a straight-in and straight-out route i.e. no restriction due to the shape of the port and travel path the air must take, improving Inlet Velocity and and therefore Volumetric efficiency and that is why they can produce more power. Sweeping unburned fuel into the next combustion event is great for environmental pollution reasons, but not great for power. It basically depends upon what sort of power you want in which direction you want to go.
For straight out efficiency PP is the way to go, the biggest hurdle is having a reliable port that doesn't leak coolant into the combustion chamber, this can be achieved with an imaginative design for IP reason I can't comment further -sorry.
George
 

dwalker

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Sorry Dwalker I should have said small PP intake port with side ports. What you seem to be missing is the side intake and exhaust ports are restrictive due to the nature of the ports themselves, they may well be oversized for this very reason; however PP provide a straight-in and straight-out route i.e. no restriction due to the shape of the port and travel path the air must take, improving Inlet Velocity and and therefore Volumetric efficiency and that is why they can produce more power. Sweeping unburned fuel into the next combustion event is great for environmental pollution reasons, but not great for power. It basically depends upon what sort of power you want in which direction you want to go.
For straight out efficiency PP is the way to go, the biggest hurdle is having a reliable port that doesn't leak coolant into the combustion chamber, this can be achieved with an imaginative design for IP reason I can't comment further -sorry.
George

This is why I advocate for the standard 13B-REW with Renesis rotating assembly.

Also I disagree with the PP being more efficient than the side intake ports. It *can* make more power, but at the expense of low and mid-range power and all economy. I am aware that some (Rob Golden from Pineapple for example) have managed to build street driven PP rotary engines, however, they were still a study in compromise.

Now if I had an engine development lab and a massive pile of money to spend making one-off parts, testing, then repeat, it is entirely possible a variable length and volume intake manifold could make the PP usable, but I do not have such things, and currently there is almost zero interest in the commercial use of it.

I will note that the UAV companies apparently did get full PP motors to work fairly well, but most of thier work and findings are also apparently super secret squirrel stuff that mere mortals are not privvy to.
 

Lendo

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dwalker, you are probably aware the Original Powersport partners did recognize the low rpm roughness and controlled that with a butterfly in the housing. it seems the closer you can get to the inner port the better the results - however there are better approaches than that.

Urquiola I went down that road of a single Rotor, you can cut the power down by half but not the overall weight and there is the additional Eccentric shaft manufacture, rotor oiling issue, loss of the rocking couple with balancing issues, the list goes on. Better to buy Aluminium end and middle housings.
George
 

rv7charlie

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What George just said about custom fab of parts obviously applies in principle to swapping out the rotating assy, P-porting, etc etc.

Most of us (Don excluded, of course), if we're honest with ourselves, are walking the 'skillset edge', just to get a stock core engine to a state where it's usable in an a/c. While the rotary is technically dirt simple, and technically capable of prodigious HP numbers, wandering away from stock config and especially trying to extract more than stock HP is a high risk endeavor for us. As much experience as Tracy had with the rotary, he bought both his Renesis core and his 20B core from an established rotary engine builder with a strong reputation for quality builds. No doubt some of that choice was simply time saving, but knowing that the core will 'just work' is worth a lot, especially when so much around it must be changed for a/c use.

I have little doubt that a P-intake Renesis with reduced-diameter P port 'timed' later to minimize overlap would be lighter (simpler intake), produce more usable power than a stock Renesis even in the lower rpm range (5k-7k rpm), and would be quieter/less offensive in sound than a 13B, but it won't be the 1st rotary I fly, because Dirty Harry was right.

Charlie
 

dwalker

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What George just said about custom fab of parts obviously applies in principle to swapping out the rotating assy, P-porting, etc etc.

Most of us (Don excluded, of course), if we're honest with ourselves, are walking the 'skillset edge', just to get a stock core engine to a state where it's usable in an a/c. While the rotary is technically dirt simple, and technically capable of prodigious HP numbers, wandering away from stock config and especially trying to extract more than stock HP is a high risk endeavor for us. As much experience as Tracy had with the rotary, he bought both his Renesis core and his 20B core from an established rotary engine builder with a strong reputation for quality builds. No doubt some of that choice was simply time saving, but knowing that the core will 'just work' is worth a lot, especially when so much around it must be changed for a/c use.

I have little doubt that a P-intake Renesis with reduced-diameter P port 'timed' later to minimize overlap would be lighter (simpler intake), produce more usable power than a stock Renesis even in the lower rpm range (5k-7k rpm), and would be quieter/less offensive in sound than a 13B, but it won't be the 1st rotary I fly, because Dirty Harry was right.

Charlie

I like where your head is at.
 

dwalker

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Kyle Mohan Racing has several vids on how-to properly do a Hybrid Renesis/13b engine.. (5 exhaust ports: 3 slots + 2 PP ports) He and Atkins Rotary sell the 5 port flanges..

Hybrid Renesis Rotary Engine Explained, what it needs, Mazda RX8 Kyle Mohan Racing, Mazdatrix - YouTube
Kyle's engine never made the power they expected, and they shelved the project. They expected 600-800hp, and never made much over 450. No idea why they are pulling it back out now other than that they might can sell some product- like thier cnc exhaust flange- or get some youtube hits. It was never really reliability. They stopped using it in his drift car when he was with Mazdatrix because even with a pretty well designed turbo system it made less power than a peripheral port 13B, and a standard Renny with a turbo will make not much less power on boost. For reference, a stock port stock keg Renny will make mid-300hp reliably, 450 if you really want it to, and uses off the shelf parts to do it. A stock keg 13B-REW with a small turbo, like a GT3582R or similar will make 500hp, all day, every day, for far less time, money, and complexity, and most importantly, more reliably. And again using off the shelf parts.

There have been a lot of things tried with varying levels of success, and there always seems to be someone who is building a "6-port" motor "that will work this time" because of XYZ porting or gadget or whatever. I was actually one of them. I built a couple of different versions of the 6port motor including a special rotor housing that was being experimented with that used a "mail slot" exhaust port to try and not kill the exhaust velocity and prevent reversion. In this case all the talk of "balancing the airflow" has never panned out, because the exhaust flow and velocity just are not happy.
The problems with a 5-port exhaust setup is you lose far more than you can make up, because a rotary performs very much like a port tuned 2-stroke motor and just carving out a massive exhaust port rarely works. There was a fellow that is a pretty bright guy a couple of years ago that went through a lot of trouble to design an impressive aluminum intake manifold and spent a fair amount of time and effort to try and make more power with the "6-port", posted tons of FB and youtube info on his build, got it done, started testing, and faded away. Because the power just was not there. He would have made more power cheaper by simply building an RE or REW motor and dropping it into his RX8.

For an airplane? NFW. Nope. Uh-Uh.
 

Urquiola

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I failed in finding a single rotor shaft for Renesis, to test my concept of a Reed-Valve controlled peripheral intake port with the existing side intake ports clogged, and the side exhaust ports kept. See attached patents. Blessings +Intake port timing -from RE K Yamamoto 1981.jpg Rectangular vs Round Intake Port NSU.jpg VW Porsche 914 vs Porsche 914 Wankel NSU -1972.jpg Reed-Valve RCEs 1978.jpg
 

Attachments

  • Reed-Valve assembly for RE Ford 1979 CA1045553A2.pdf
    292.6 KB · Views: 1
  • Induction-Exhaust R-V System for a RE Ford 1978 CA1032477A1.pdf
    1.4 MB · Views: 0
  • Kawasaki -Combustion Promoting Improvement in RE US3848574A.pdf
    255.8 KB · Views: 0
  • Yanmar Diesel Reed-Valve data -SAE paper 720466.pdf
    293.2 KB · Views: 1

kevink0000

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Nov 15, 2022
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Arizona
Kyle's engine never made the power they expected, and they shelved the project. They expected 600-800hp, and never made much over 450. No idea why they are pulling it back out now other than that they might can sell some product- like thier cnc exhaust flange- or get some youtube hits. It was never really reliability. They stopped using it in his drift car when he was with Mazdatrix because even with a pretty well designed turbo system it made less power than a peripheral port 13B, and a standard Renny with a turbo will make not much less power on boost. For reference, a stock port stock keg Renny will make mid-300hp reliably, 450 if you really want it to, and uses off the shelf parts to do it. A stock keg 13B-REW with a small turbo, like a GT3582R or similar will make 500hp, all day, every day, for far less time, money, and complexity, and most importantly, more reliably. And again using off the shelf parts.

There have been a lot of things tried with varying levels of success, and there always seems to be someone who is building a "6-port" motor "that will work this time" because of XYZ porting or gadget or whatever. I was actually one of them. I built a couple of different versions of the 6port motor including a special rotor housing that was being experimented with that used a "mail slot" exhaust port to try and not kill the exhaust velocity and prevent reversion. In this case all the talk of "balancing the airflow" has never panned out, because the exhaust flow and velocity just are not happy.
The problems with a 5-port exhaust setup is you lose far more than you can make up, because a rotary performs very much like a port tuned 2-stroke motor and just carving out a massive exhaust port rarely works. There was a fellow that is a pretty bright guy a couple of years ago that went through a lot of trouble to design an impressive aluminum intake manifold and spent a fair amount of time and effort to try and make more power with the "6-port", posted tons of FB and youtube info on his build, got it done, started testing, and faded away. Because the power just was not there. He would have made more power cheaper by simply building an RE or REW motor and dropping it into his RX8.

For an airplane? NFW. Nope. Uh-Uh.
Dwalker,

I am interested in your PP Renesis build. I know many are looking for an angle on this, to find the missing link unlocking more power/efficiency for the Renesis, and I agree with you, the projects have been unsatisfying. My only question to you at this time, is what port timing did you use for the "mailslot" port in your build? I am not an airplane guy, just an RX8 guy, and glad to find this forum where these topics get discussed politely, something that seldom happens on the RX8 site. Thank you. -Kevin.
 
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