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"horrendous instantaneous torque signature" is not true and its a lot better with a wankel than with a piston engine. Fake news, I say.
Dave Leonard
I am always amazed when asking about this subject on rotary engine PSRU’s. This from EPI, the maker and supposed expert on redrives…………. Marc Marc: I have not done any PSRU systems for Wankel-type engines, primarily because of the horrendous instantaneous torque signature they exhibit, thus the difficulty in properly attenuating the excitation pulses into the gearbox (and prop). Good luck with your project. Sincerely, Jack Kane EPI, Inc. Dave and all, My prop shaft is on timken taper bearings, so does not need the pressure feed. Matt is too polite to tell the whole story. The initial run did not get enough oil to the bronze bush between the input shaft and the prop shaft --- so it did what all oil starved bearings do --- it melted. Luckily Matt had his rubber cushion drive self destruct as well-- I say luckily as that caused the dismantle of the redrive which found the cooked bronze bush. Fortunately no other damage. This prompted us to make the unit self contained as for lubrication. Heat may be a problem, but I doubt it and time will soon tell. Rubber cushion drive --- Matt has really copped the "pineapple" on this. Finally turns out that the rubber firm used the wrong rubber --- Still chasing that problem down but appears lack of communication between the office and the workman doing the job. In ignorance and lack of knowledge he put the wrong rubber in--- totally different rubber to the one I am running currently. These cushion drives will be subject to recall and the proper rubber fitted. Very embarrassing and infuriating for me. So as info becomes available I will post, but the self contained oil should work well and will simplify things. Neil. Well said, Charlie. Here is Neil's page with diagrams: BTW, very nicely done Neil. Best I can tell it is a pressure fed bearing just like Tracys. Matt,
I've not followed Neil's version of the drive carefully; he may not be using a sleeve bearing. But Tracy's drive *does* use one, under that oil feed hole in the 'fat' part of the housing. Dave's telling you that if there's a sleeve type bearing in there that's designed for pressure feeding, lack of oil pressure is certain death, in short order. If Neil is using a ball or roller bearing back there, that's a different game entirely, and I'd want his input on whether it needs pressurized flow, both for lube and for cooling.
On 5/8/2019 3:44 PM, Matt Boiteau mattboiteau@gmail.com wrote: Neil's. 3.17 ratio. I've found the back gears push the oil to the front pretty well. Matt, is this one of Tracy Crooks drives? If so, it will absolutely fail in short order with no pressure feed to the main bearing. So far on the ground, static 2200 prop rpm for 30seconds, temps only got to 135°F.
Haven't flown yet. Will advise in June. So you are trying using self contained lube with no pressure feed from the engine and no drain...…...Watch your temps......…….Let us know what happens...…... I've been experimenting on Neil's PSRU with sealing it up. Only adding a breather vent on the rear housing. So far I've only done ground testing, but all seems well enough to fly with it soon enough. The Tygon house in the picture was only to see the oil flow, it's capped off now. I ran gear oil 70w-140 and it was way to thick and came out the breather vent, so went back down to my normal engine oil 20w-50. Filled half full, but I think I can go a little less, haven't tested the idle level yet.
I have a temp sensor (1/3 down), and a digital level sensor (half way) installed in the rear housing as well.
On 2019-05-07 12:32:26 PM, Steven W. Boese SBoese@uwyo.edu <flyrotary@lancaironline.net> wrote: If the original return line was not enlarged, the "vent" line simply acted as an additional return line and my gearboxes operated completely filled with oil.
Steve Boese
> On May 7, 2019, at 9:41 AM, Jeff Whaley jwhaley@datacast.com wrote:
>
> ◆ This message was sent from a non-UWYO address. Please exercise caution when clicking links or opening attachments from external sources.
>
>
> Hi Steve, is the enlarging of the oil return necessary?
> I thought you first tried enlarging the return line expecting it to improve draining, only to find no improvement until the vent line was added.
> Jeff
>
> Jeff,
> At this point I have only 3 hr of flight time on the gearbox with the modified drain and vent. I have not observed a significant effect with respect to power absorption or heat generation.
>
> Connecting the vent line to the foot of the rotor housing was ineffective even though this location was above the oil level. Connecting the vent line to the area of the oil filler opening at the top of the center iron allowed the gearbox to drain as intended.
>
> The most troublesome part of the modification was enlarging the oil return to 1/2" NPT in the rotor housing foot.
>
> Steve Boese
>
>
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