Roarks
Active Member
New Radial engine.
So...
I started in over at the propeller thread and got a lot of great information, lets see how the engine thread goes...
I've been working on a ground up engine design. I think I started the first assembly model back in 2013 and have been refining things since. The amount of effort and education I've put into this thing is ridiculous. I want to say it's a significant factor to me getting my A&P cert, spent thousands on books, and an engineering friend that works at GM probably thinks oh **** here goes another hour when I call.
I've gotten distracted a few times. I've played with low altitude turbine design, I've played with 2 stroke and 4 stroke diesel with fancy fuel injection, tried spark ignition jet A... which there might still be something there but my "carb" fouls itself in a matter of hours... The more I mess with the exotic stuff the more I realize by the time I'm done with my RV8 kit... Electric will probably be a serious option. I'm a mechanical engineer not an EE PHD and battery materials research scientist. I build metal things.
So why not do something simple, tried and true, and cool... A RADIAL! Plain old aviation style, air cooled, 100LL radial. (Does anyone actually use their mogas STC? Where do you get non ethanol fuel that's cheaper than 100LL!?)
(is the guy that made the RV-8R around here, I would love to ask some questions regarding airframe mods, thrust line so on...)
My day job is an Aerospace engineer and I focus a lot on manufacturing. My first design point is manufacturabiliy with pretty much any CNC is a must. That removes specialized processes and makes low quantities a non-issue... just ask any company that used to do aircraft forgings, low cost maching has really changed the game... and 3D printing is getting insane. I've designed 3 plastic 3D printed parts that are flying in the past year. There are so many starving machine shops out there... I put out an RFQ on the cam plate and I had 4 companies beating each other up over price in under an hour. If a call an Asian manufacturing broker... the prices are laughable.
Second is my A&P training... Maintenance and ownership. I'm trying to make this thing so AS much as possible can be done without blowing it apart. Need to replace lifters, they are externally accessible. Oil pump... LRU. I want to include a pre-oiler/figure out if an external oil cycling system would be good... kind of like a battery tender but for oil, I'ts dry sump obviously so I figure good hydraulic QD fittings could be included. Maybe a few smart placed inspection ports.
Electronic ignition... No Magnetos...It's experimental. How many of you have taken apart a magneto and looked at that little I think its a #8-32 pan head phillips screw @ 6 inch-pounds that goes into a zinc housing that sets the breaker gap... not to mention plastic gears. Yeah. They work but I'm not about to make a custom magneto or rely on some NOS. Besides what I can do with a simple brain box stuffed in a nice 6061-T6 ECU housing with 38999 connectors and OEM Automotive ignition coil packs is pretty cool.
I think I want to start with a carburetor. KISS. I was talking about going nuts with a fuel management system but my GM buddy thinks that's currently beyond my scope of work. I really like the AeroVee AeroInjector but for proof of concept I bet a MA-4-5 will work. Most everyone I talk to that have a COTS system is set up for 4 or 6 cylinder. No love for Odd number radials. If you know of someone let me know.
As much as I want to fool with Supercharging, and turbos... I'm not going to for the first one. There may be a "mixing fan" in the induction manifold but that's it, nothing geared. Math says it should get about a half inch at most.
The crank is a single throw (short, stubby, much lighter than typical horizontally opposed), made up of multiple parts... assembled like a jet engine shaft. Hopefully I can couple it with a wooden/composite prop... I would like to see prop strike events to become a much lower cost ordeal. That I think right there is what scares me the most about typical aircraft engines... I can replace just about everything reasonably on a good $4k core, but if that crank or the cam is bad... I lost... I don't gamble. I want that issue to disappear.
Cam shaft is gone. Replaced with a cam plate that will be bathed in oil. I've got a friend that's a lubrication engineer and I've yet to get a verdict on going to a precipitation hardening stainless. No reason to use 1930's alloys. Hydraulic Roller lifters.
I want to say it's very conservative in it's design. It's 5 cylinders. Direct dive. I'm aiming for just under 200hp (I could still shift up to 250 but I think that's a bit much for an RV?) at 2700 RPM red line. No planetary gears... looking down the road so any "P" can work on it. I tried so very hard to get it the same width as an O-320 but its about 2 inches wider... and obviously round. It's a little under the weight of an O-320... I was hoping to go with a nylon induction housing (just about every GM product in the past decade) but I'm not sure it can survive behind an air cooled monster. By the time I have every bolt and bearing in there it will probably be about the same.
I would very much like to hear the thoughts of the community... maybe an outstanding maintenance issue or cost I haven't thought of that could be designed out.
What's your engine wish list?
What's put your plane out of annual or for sale that's engine related?
I'm going to make mine...If it works... I imagine I could make it a kit a la AeroVee. Once I get it near finalized, or actually get one built I'll let the cat out of the bag if there's interest... I think everyone's head would explode. It's really simple in concept. I'm tired of aviation being so ridiculously expensive I want to change that.
So...
I started in over at the propeller thread and got a lot of great information, lets see how the engine thread goes...
I've been working on a ground up engine design. I think I started the first assembly model back in 2013 and have been refining things since. The amount of effort and education I've put into this thing is ridiculous. I want to say it's a significant factor to me getting my A&P cert, spent thousands on books, and an engineering friend that works at GM probably thinks oh **** here goes another hour when I call.
I've gotten distracted a few times. I've played with low altitude turbine design, I've played with 2 stroke and 4 stroke diesel with fancy fuel injection, tried spark ignition jet A... which there might still be something there but my "carb" fouls itself in a matter of hours... The more I mess with the exotic stuff the more I realize by the time I'm done with my RV8 kit... Electric will probably be a serious option. I'm a mechanical engineer not an EE PHD and battery materials research scientist. I build metal things.
So why not do something simple, tried and true, and cool... A RADIAL! Plain old aviation style, air cooled, 100LL radial. (Does anyone actually use their mogas STC? Where do you get non ethanol fuel that's cheaper than 100LL!?)
(is the guy that made the RV-8R around here, I would love to ask some questions regarding airframe mods, thrust line so on...)
My day job is an Aerospace engineer and I focus a lot on manufacturing. My first design point is manufacturabiliy with pretty much any CNC is a must. That removes specialized processes and makes low quantities a non-issue... just ask any company that used to do aircraft forgings, low cost maching has really changed the game... and 3D printing is getting insane. I've designed 3 plastic 3D printed parts that are flying in the past year. There are so many starving machine shops out there... I put out an RFQ on the cam plate and I had 4 companies beating each other up over price in under an hour. If a call an Asian manufacturing broker... the prices are laughable.
Second is my A&P training... Maintenance and ownership. I'm trying to make this thing so AS much as possible can be done without blowing it apart. Need to replace lifters, they are externally accessible. Oil pump... LRU. I want to include a pre-oiler/figure out if an external oil cycling system would be good... kind of like a battery tender but for oil, I'ts dry sump obviously so I figure good hydraulic QD fittings could be included. Maybe a few smart placed inspection ports.
Electronic ignition... No Magnetos...It's experimental. How many of you have taken apart a magneto and looked at that little I think its a #8-32 pan head phillips screw @ 6 inch-pounds that goes into a zinc housing that sets the breaker gap... not to mention plastic gears. Yeah. They work but I'm not about to make a custom magneto or rely on some NOS. Besides what I can do with a simple brain box stuffed in a nice 6061-T6 ECU housing with 38999 connectors and OEM Automotive ignition coil packs is pretty cool.
I think I want to start with a carburetor. KISS. I was talking about going nuts with a fuel management system but my GM buddy thinks that's currently beyond my scope of work. I really like the AeroVee AeroInjector but for proof of concept I bet a MA-4-5 will work. Most everyone I talk to that have a COTS system is set up for 4 or 6 cylinder. No love for Odd number radials. If you know of someone let me know.
As much as I want to fool with Supercharging, and turbos... I'm not going to for the first one. There may be a "mixing fan" in the induction manifold but that's it, nothing geared. Math says it should get about a half inch at most.
The crank is a single throw (short, stubby, much lighter than typical horizontally opposed), made up of multiple parts... assembled like a jet engine shaft. Hopefully I can couple it with a wooden/composite prop... I would like to see prop strike events to become a much lower cost ordeal. That I think right there is what scares me the most about typical aircraft engines... I can replace just about everything reasonably on a good $4k core, but if that crank or the cam is bad... I lost... I don't gamble. I want that issue to disappear.
Cam shaft is gone. Replaced with a cam plate that will be bathed in oil. I've got a friend that's a lubrication engineer and I've yet to get a verdict on going to a precipitation hardening stainless. No reason to use 1930's alloys. Hydraulic Roller lifters.
I want to say it's very conservative in it's design. It's 5 cylinders. Direct dive. I'm aiming for just under 200hp (I could still shift up to 250 but I think that's a bit much for an RV?) at 2700 RPM red line. No planetary gears... looking down the road so any "P" can work on it. I tried so very hard to get it the same width as an O-320 but its about 2 inches wider... and obviously round. It's a little under the weight of an O-320... I was hoping to go with a nylon induction housing (just about every GM product in the past decade) but I'm not sure it can survive behind an air cooled monster. By the time I have every bolt and bearing in there it will probably be about the same.
I would very much like to hear the thoughts of the community... maybe an outstanding maintenance issue or cost I haven't thought of that could be designed out.
What's your engine wish list?
What's put your plane out of annual or for sale that's engine related?
I'm going to make mine...If it works... I imagine I could make it a kit a la AeroVee. Once I get it near finalized, or actually get one built I'll let the cat out of the bag if there's interest... I think everyone's head would explode. It's really simple in concept. I'm tired of aviation being so ridiculously expensive I want to change that.
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