flyrotary@lancaironline.net Mailing List Archive

On Sat, Jun 21, 2008 at 1:43 PM, John Overman <mooneydryver@yahoo.com> wrote:

Steve
I also have one of Bryan's upgrades. I'm not flying yet but I'm leaving the "actuator" installed and plan to control it with a control cable from the panel. In the off position that will cut off the exhaust to one of the two turbine wheels. Since I will be mostly turbo-normalizing I think it will be pretty hard to overtax the turbo.

Two turbine wheels? are you talking about the 3rd gen twin turbos for the 13B-REW? If so, those a definitely too small for aircraft use. Also, turbo normalizing is not necessarily easy on the turbo - it is just easier on the engine than running a lot of boost.

With my fix bypass wastgate I can only normalize up to about 6000. Above that, even at WOT, my MAP is less than 29". For example, at 15.5k my MAP is only 21". Much less than turbo normalized yet the turbo is still working pretty darn hard after you count losses in the system.

Tell us more about your set up.

--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net

--- On Sat, 6/21/08, Steve Brooks <cozy4pilot@gmail.com> wrote:

> From: Steve Brooks <cozy4pilot@gmail.com>
> Subject: [FlyRotary] Re: Another Turbo Bites the dust
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Date: Saturday, June 21, 2008, 1:20 PM

> David,
> Sorry to hear about your turbo. Especially sorry since I
> have one also.
> As I recall though, your turbo was an 86-87, which had a
> somewhat different
> design. When I had mine done, the core was an 89-91, which
> was about $200
> cheaper. Bryan at BNR turbo told me that the 89-91 was
> much easier to
> upgrade was the reason.
>
> I don't know if mine will last any longer though. 130
> hours of mostly WOT
> doesn't really sound all that bad. It will be
> interesting to see what went
> bad on it. Sounds like it may be the bearings though from
> the sounds of it.
>
> Regards,
> Steve Brooks
>
>
> -----Original Message-----
> From: Rotary motors in aircraft
> [mailto:flyrotary@lancaironline.net]On
> Behalf Of David Leonard
> Sent: Friday, June 20, 2008 11:47 PM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] Another Turbo Bites the dust
>
> Today I flew from San Diego to Brownville Texas to attend a
> formation flying
> clinic. After 6 hours of WOT flight I was descending
> through 5000' (down
> from 15.5k) an just a few miles from the airport when I had
> a sudden and
> sickening drop in manifold pressure. The engine was still
> running fine,
> and I had plenty of altitude to make the runway, so I
> continued on debating
> weather or not to flip the turbo oil shutoff switch. I had
> grown to respect
> this turbo so much that I finally decided that I had just
> blown out a
> fitting somewhere in the intake system downstream of the
> turbo. I even
> continued on to a low pass for show rather than just
> landing. When I
> eventually had time to take off the cowl I was dissapointed
> to find that all
> the fitting were in place and that the compressor wheel
> turns only with
> significant resistance.
>
> So the turbo is dead, and I am out of the formation clinic
> and will have to
> decide tomorrow about flying home with a dead turbo. Will
> maybe be able to
> take a look in the hot side and see what I see.
>
> This turbo was the TO4 hybrid with a fixed wide open waste
> gate. It had 130
> hrs of mostly hard duty. Sigh.
>
> --
> David Leonard
>
> Turbo Rotary RV-6 N4VY
> http://N4VY.RotaryRoster.net
> http://RotaryRoster.net

--
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