How many people are interested in a GOOD safe psru for the rotary?

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Bobby Hughes

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Jul 8, 2020
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While it is true that rubber spring elements waste a fraction of the spring energy stored and released on each cycle, they can be designed to last thousands of hours with decent airflow over them. Evidence is engine mounts on things like, cars, trucks, and airplanes and giubos used as universal joints in many automotive powertrains. These gadgets are doing the same thing - deflecting to new equilibrium position under mean torque and then vibrating while isolating the engine vibration.

Rubber springs are poor thermal conductors, which can make the task vexing. One approach that greatly extends part life is simply to use elastomers compounded to stand higher temperatures while maintaining modest temperatures with decent airflow over them.

Billski
I found that better heat shielding between the PSRU and exhaust pipe improved damper life. The last set I changed had developed only minimal flat spots. Prior to having the batch manufactured I would rotate the dampers 180 degrees opposite the flat spots at annual. This seems to allow the existing flat spots to return back to a more normal condition but likely had some permanent compression.

Bobby
 

Pale Bear

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Feb 22, 2009
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Minnesota
OK, .. using rubber, or springs in a damper design. Fluid, or viscous dampers?, instead .. surely someone has also looked into that, as well, right? I suppose that the life cycle of this kind of thing would be marginal?
 

dwalker

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Mar 6, 2021
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Billsrv4 is there any movement forward on your PSRU? I am pretty interested in it after watching the video and seeing how it is packaged.
 

Billrsv4

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Sep 29, 2016
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NW Oregon
dWalker, Due to the covid situation I lost my 9-5 job. I am still working on the reduction gear. 1 portion remains in design. I will continue but very slowly.
Wish I could say more, but there is only a small chance to make money on it. I was hoping to provide for my own aircraft and defray my costs with sales. had to stop everything to keep the lights on.
Bill
 

dwalker

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Mar 6, 2021
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dWalker, Due to the covid situation I lost my 9-5 job. I am still working on the reduction gear. 1 portion remains in design. I will continue but very slowly.
Wish I could say more, but there is only a small chance to make money on it. I was hoping to provide for my own aircraft and defray my costs with sales. had to stop everything to keep the lights on.
Bill
Completely understand, looking forward to seeing more as things hopefully improve.
 

Lendo

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Feb 6, 2013
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628
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Brisbane
dwalker, I understand the PSRU design is very good, but what Bill has also done is develop a fail safe, Peripheral Port (PP). Don't know the exact design, but what I do know is it's his IP and I can't discuss the little I do know. Most PP's are prone to leaking water (coolant) into the Combustion Chamber - not a good thing as well you might imagine. I had some ideas but his is much better.
George
 

dwalker

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Mar 6, 2021
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56
dwalker, I understand the PSRU design is very good, but what Bill has also done is develop a fail safe, Peripheral Port (PP). Don't know the exact design, but what I do know is it's his IP and I can't discuss the little I do know. Most PP's are prone to leaking water (coolant) into the Combustion Chamber - not a good thing as well you might imagine. I had some ideas but his is much better.
George
I am pretty set against peripheral ports for my application. I do have, and plan on using, a set of semi-peripheral port housings. These are done in such a way that they are unlikely to leak into the rotor housing, and the method of attaching to the intake manifold itself is o-ringed to prevent coolant from being sucked into the intake or worse, the coolant becoming pressurized under boost.
 

rv7charlie

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Nov 17, 2014
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Jackson
No need to bother him; it's a Real World Solutions drive, designed/mfgrd by Tracy Crook.

BTW, two things immediately jump out at me in that image. First is, wondering how much pitch-up range is there with the backseat stick in place and that big box in the back seat. The other is the pilot's shoulder belt attach point. Safety wonks say the over-the-shoulder, to the floor mounting point will result in compressed vertebrae in an accident.
 
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Lendo

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Feb 6, 2013
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Brisbane
dwalker. I guess your concern with the PP is low rpm rough idle. I believe Powersport solved that with Butterfly in Port housing, close to the combustion chamber.
I'm unsure as to the exact nature of Bill's design, but he feels he has that sorted, also port sizing is important for our low RPM power requirements, 6,000 to 6,500 approx. The correct PP size is excellent of Volumetric Efficiency and a smaller port does that with higher velocity and I'm guessing a butterfly in the port controls the lower end flow and keeps things running smoothly at the lowest of RPM.
Just my take on it all
George
 

dwalker

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Mar 6, 2021
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56
dwalker. I guess your concern with the PP is low rpm rough idle. I believe Powersport solved that with Butterfly in Port housing, close to the combustion chamber.
I'm unsure as to the exact nature of Bill's design, but he feels he has that sorted, also port sizing is important for our low RPM power requirements, 6,000 to 6,500 approx. The correct PP size is excellent of Volumetric Efficiency and a smaller port does that with higher velocity and I'm guessing a butterfly in the port controls the lower end flow and keeps things running smoothly at the lowest of RPM.
Just my take on it all
George
My concern with any type of P-Port is they tend to leak. Even if they are steel and welded in place to the steel liner, over time the weld can crack. The aluminum press fit, stepped, and sealed full P-port setups have gotten very reliable these days. Even so, I am strongly considering not using the semi-p port housings I have and instead using standard Series 6-8 rotor housings.
If I were going NA, I would strongly consider going P-Port, but since I am going to use boost I feel like the semi-P will be just about right to give good power in the 6000rpm range with good economy and the ability to throttle back and cruise with good power as well. I could be wrong, almost all of my P-Port experience is in engines turning 8-9K rpm continuous, so my frame of reference may be skewed.
 

Lendo

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Feb 6, 2013
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628
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Brisbane
dwalker, I would suggest you speak to Billrsv4, I'm sure he would agree with you on PP leaks, however as an Engineer, I'm sure he has that all sorted, maybe a private discussion seeing your degree of knowledge and experience. My thought are why put in a Turbo considering weight and additional complexity. If the Turbo was for attitude compensation power- well that's another thing.
Just being the Devils advocate here.
I wish we had a lot more builders heading in the same direction.
George
 
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