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Mazda Rotary Engine

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rv7charlie

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Nov 17, 2014
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Jackson
Google 'specific heat of oil vs water'. There's good reason you almost never see oil as the primary cooling fluid. (Though I did have a 1970 Alfa Romeo Spyder that gave it a shot, before I pulled the head to install the missing O-rings in all the block-to-head oil passages.)

I think we've discussed this here in the past; a single rotor rotary pays a big weight penalty compared to a 2 rotor, due to balance requirements. It'll likely pay another penalty in the reduction drive, due to increased weight requirements in the flywheel, 'damper' assemblies, and gears, because of the higher and lower frequency peak-to-average torque pulses.

Charlie
 

TFF

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Apr 28, 2010
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Memphis, TN
My Alfa Spider drools the oil out the right front corner. Never special mix though. I have put up with it for a long time. If the o ring is missing, I don’t know who to blame.
 

rv7charlie

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Nov 17, 2014
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Jackson
Mine was missing *all* the O-rings in the pressure-fed paths from block to head. I realized it when delicious looking pale chocolate milk starting overflowing out the radiator reservoir.
 

Billrsv4

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Joined
Sep 29, 2016
Messages
146
Location
NW Oregon
I would think the best possible surface would be chrome like the rotor housings. Grinding the HardChrome flat would be relatively easy.
Aircab you might think that chrome was best but the early Powersport tried many surfaces. The reason for the braised side plates is that they can be nitrided hard. That is a chemical change of the material itself on a molelecular level. It can’t flake or peel like chrome can. That was the best anyone, including Mazda came up with. Excepting the detonation gun coating used on the Le Mans engine. That was the best and incredibly expensive! Had to be Diamond ground, but worked if you were willing to pay 10-20 times the normal price.
Bill
 

erkki67

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Joined
Feb 18, 2010
Messages
2,376
Location
Romont / Fribourg / Switzerland
Its not a Mazda, but have a look at the not so new Geiger Wankel engines. They claim to have found the solution for the exesive oil and fuel consumption.


they have a 50 and 100hp engine, and they have coupled 2 100hp engines via a gearbox.
 

Powersport Aviation

New Member
Joined
Sep 9, 2019
Messages
3
Greetings from Powersport! A few of you have sent emails to me looking for information, but I see that others state they have not heard back. Please make sure you use the correct ending: .org The .com domain name was stolen and we cannot get it back, so we went with the reasonable alternative.
tjames@powersportaviation.org
The chatter about the "super light" engine is interesting, and much of the information is correct. However, I do have the original engine on my shelf, and I can tell you that there are many issues are that led to the evolution to the current engine. The "super light" was relatively powerful but not durable and would be very expensive to produce.
I will try to respond to emails as my time permits.
 

Lendo

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Joined
Feb 6, 2013
Messages
602
Location
Brisbane
Urquiola, It's got to do with the expansion rate of water in the combustion chamber. If it leaks a little, it most likely will get worse.
George
 

AIRCAB

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Joined
Feb 6, 2015
Messages
115
Location
Vancouver Island
Aircab you might think that chrome was best but the early Powersport tried many surfaces. The reason for the braised side plates is that they can be nitrided hard. That is a chemical change of the material itself on a molelecular level. It can’t flake or peel like chrome can. That was the best anyone, including Mazda came up with. Excepting the detonation gun coating used on the Le Mans engine. That was the best and incredibly expensive! Had to be Diamond ground, but worked if you were willing to pay 10-20 times the normal price.
Bill
The braised housings would have realized consible weight savings, otherwise what's the point. It would be interesting to know what post treatment the aussie are doing to their replaceable inserts. I have been told by some racers, that most do NO treatment after grinding and lapping.
 

Urquiola

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Joined
Aug 23, 2013
Messages
132
Location
Madrid, Spain
Google 'specific heat of oil vs water'. There's good reason you almost never see oil as the primary cooling fluid. (Though I did have a 1970 Alfa Romeo Spyder that gave it a shot, before I pulled the head to install the missing O-rings in all the block-to-head oil passages.)

I think we've discussed this here in the past; a single rotor rotary pays a big weight penalty compared to a 2 rotor, due to balance requirements. It'll likely pay another penalty in the reduction drive, due to increased weight requirements in the flywheel, 'damper' assemblies, and gears, because of the higher and lower frequency peak-to-average torque pulses.

Charlie
Deutz in Cologne produces some industrial engines with oil instead of water as cooling fluid, about heat transport features, the 'BOSCH Manual of Automobile technique' includes data about most materials used in automobiles; from the heat transport, viscosity, specific gravity properties of oil and water, you can calculate the pump, the radiator,...
Old twin-flat Citroën Series A cars engines (2CV, Ami, Dyane, Mehari) had Air Cooled cylinders, but some parts had oil cooling, with the help of a pump and a radiator. The Voisin designed 'Biscooter' micro-Biscuter a.jpgBiscuter b.jpgcar, all aluminum, there was aluminum surplus after WW II, with a 2-Strokes engine, had a large engine head, filled with oil, to avoid too much cooling and shock cooling on highway, overheating in traffic lights, oil acting as a 'heat buffer'.
OMC had hard chrome working surface in their Snowmobile Wankel RCEs, it seems was deposited by electric means; after layer was complete, they reversed polarity for some 15-20 min, in order of having porosity in working surface allowing lubricating oil to attach. Suzuki seems used a flame sprayed technology, from Canadian patents by Alfred P Grazen; NSU, Comotor, had nikasil.

About torque steadiness in a single rotor Wankel, it are comparable to a three cylinder engine, it's not that good as a twin-rotor, having the torque uniformity of a 6 cylinder engine, but is good enough, Daewoo and other carmakers offer three cylinder engines, no specific complaints.

The advantage in a single rotor Wankel is with its reduced displacement compared to units with more discs, chances are most time engine will be working in a favorable BMEP environment, and this is a core element in economy and emissions.
An ordinary auto, running on a flat road at 55 mph may use no more than 25 HP, please read:
+ 'How much overall energy does the Automobile require?', SAE Journal Automotive Engineering, vol 80, n 7, pp 36-38, Jul 1972
+ 'How much Energy is needed to produce an Automobile?', SAE Journal Automotive Engineering, vol 80, n 7, pp 39-40, Jul 1972.
+ SAE paper 2013-32-9161: 'The Intake and Exhaust Pipe effect on Rotary Engine performance', from Taiwan.

About power needs in airplanes, lots of references and charts were added in this HomebuiltAirplanes.com site.
The 'How green is green energy?' article is from Scientific American (SciAm)
Blessings +Balancing Condition of RE -K Yamamoto a .jpgBalancing Condition of RE -K Yamamoto b.jpg
 

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