Mailing List flyrotary@lancaironline.net Message #64760
From: David Leonard wdleonard@gmail.com <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Venting the Reduction Drive
Date: Wed, 8 May 2019 15:26:17 -0700
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Hi Matt,

So when you had that bit of tubing on the vent and the bearing inlet, you could see oil flowing up and back into the vent?  

In your previous responses you noted that "ground testing for 30 seconds at 2200 RPM prop"  and now "all seems well enough to fly with it soon".  Yet , the temps got to 130 deg after only 30 seconds...???  I suspect that your stated ground testing may be insufficient.  

I have personally failed a main bearing on Tracys Drive.  True, I was racing at Reno using about 300hp, but I also had 80 psi of oil going into that main bearing along with a cooling system.  I suspect that failure to provide pressurized oil to the main bearing may be insufficient.

Just trying to save you from burning out a gear drive and a glider landing like I did.

Best,
Dave Leonard

 

On Wed, May 8, 2019 at 1:45 PM Matt Boiteau mattboiteau@gmail.com <flyrotary@lancaironline.net> wrote:
Neil's. 3.17 ratio.
I've found the back gears push the oil to the front pretty well.

- Matt Boiteau

On Wed, May 8, 2019, 13:13 David Leonard wdleonard@gmail.com <flyrotary@lancaironline.net> wrote:
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.

Dave Leonard.

On Wed, May 8, 2019, 7:03 AM Matt Boiteau mattboiteau@gmail.com <flyrotary@lancaironline.net> wrote:
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.

- Matt Boiteau

On Wed, May 8, 2019, 00:09 Kelly Troyer keltro@gmail.com <flyrotary@lancaironline.net> wrote:
Matt,
  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...…...

Kelly Troyer 

On Tue, May 7, 2019 at 10:15 PM Matt Boiteau mattboiteau@gmail.com <flyrotary@lancaironline.net> wrote:
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.

- Matt Boiteau

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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