From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Re: Turbos
Date: Sat, 9 May 2020 17:21:44 +0800
References: <list-224097@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-224097@logan.com>
Message-Id: <94462409-AFE3-4B4B-ACB1-E96FE41FF116@gmail.com>

Thanks Todd.
Is there such a thing as a controller that references ambient pressure =
as the reference so that charge remains constant.
I=E2=80=99m asking more from interest than wanting this in the future. I =
thought cars might use such a system to adjust for altitude.

Cheers
Steve

> On 9 May 2020, at 4:00 pm, Todd Bartrim bartrim@gmail.com =
<flyrotary@lancaironline.net> wrote:
>=20
> Hi Steve;
>   I did use the standard actuator until the diaphragm burst during =
take-off resulting in a very impressive climb rate. I replaced it with =
this one on ebay
>      https://www.ebay.com/itm/262896884959
> It is a piston rather than a diaphragm. The diaphragm will react =
faster than a piston, but for our application it shouldn't matter, but =
the piston is far more reliable. To rebuild this is simply changing the =
o-ring. The mounting bracket that comes with it will fit if your =
compressor outlet is in the stock configuration, but as mine has been =
rotated to have the outlet at the 9:00 position, I had to heavily modify =
it to fit. Not a big deal if you can weld aluminum.
> For boost control I use a TurboSmart electronic boost controller like =
this one
>     https://www.turbosmart.com/product/eboost2-60mm-black/=20
> Mine is the earlier version (not the 2) and was no where near this =
pricey (I think it was around $400cad), but as far as I can see, just as =
functional. Now keep in mind that it won't reduce your boost to =
pressures below the spring pressure, so use the lowest spring that you =
can get and that will be your minimum boost pressure. Then you preset =
your desired boost levels in the controller and at the touch of a button =
you can get increased boost. It works simply by switching a small =
Numatics 3-way solenoid to vent some of the air pressure from the hose =
connecting the compressor outlet to the actuator. Simple but effective.
>  I have a 6psi spring and have my setpoints set at 9psi and 12psi. =
I've not needed to use them yet, so this expense could probably be =
saved.
>=20
> Todd Bartrim
> C-FSTB
> RV9
> 13B Turbo Rotary Engine
>=20
>=20
> On Fri, May 8, 2020 at 4:15 PM Stephen Izett stephen.izett@gmail.com =
<flyrotary@lancaironline.net> wrote:
> Hi guys.
> Another turbo question.
> Do you guys just use a standard waste gate actuator (perhaps with =
basic controller allowing different boost settings) and run out of boost =
at x altitude, or do you have some kind of altitude compensation?
> Thanks
> Steve Izett
>=20
>=20
> > On 9 May 2020, at 6:24 am, 12348ung@gmail.com =
<flyrotary@lancaironline.net> wrote:
> >=20
> > Dave and contributors,
> >                                            Spent yesterday finally =
getting specific answers that I should have had 12 months ago.  The guru =
that I sent the stock turbo to in the end had no idea as to an upgrade =
for temp in the hot section.  The up grade that Dave suggested is =
approx. $900 USD.  Real problem at the moment is the exchange rate with =
all the bank charges,  the great Ozzie dollar is approx. half.  Then =
freight----  I see freight on a turbo from the US at up to $800 Oz =
dollars!!   Then internal freight in OZ, plus labour costs  ---  I will =
have to sell 2 kidneys!
> >                 Then considering I do not have a stock RX7 manifold =
to bolt the turbo to =E2=80=93 I am manufacturing an adaption of the =
stock Renesis  manifold, so whatever turbo I get it means work to make =
it fit and I am =C2=BE down that path.  So having already having a =
=E2=80=9Cdummy spit=E2=80=9D due to 12 months lost, I lauch out to find =
a new turbo in OZ.  I find that Garret and others have a hot section =
wheel that will stand 1050 degrees C!!  Wow that fixes anything that the =
rotary puts out with no phone calls involved trying to explain.    Once =
again I make the usual; mistake telling the company with all these shiny =
new turbos that I want it for a drone!!  Thought that would by pass the =
usual arguments---- silly boy, NO they do not supply for aeronautical =
applications!!  So I am back to =E2=80=9Cdune buggy=E2=80=9D even though =
the nearest beach is 300 miles away.  Seems the turbo I require is the =
smallest they make.  Price is yet to enter the discussion.
> >                 Will update as I get abused.  I am asked continually =
for Make, Model, Vin Number, year of manufacturer!  All I want is a =
turbo!
> > Thanks to all,
> > Neil.
> > =20
> > From: Rotary motors in aircraft <flyrotary@lancaironline.net>=20
> > Sent: Friday, May 8, 2020 11:17 PM
> > To: Rotary motors in aircraft <flyrotary@lancaironline.net>
> > Subject: [FlyRotary] Re: Turbos
> > =20
> > Hi Neil,
> > It all depends on how you size and operate your turbo.
> > In general, the pressure relief, or pop-off valve is not needed in =
aircraft.  Those come more into play during the fast throttle closures =
that occur in highly boosted race cars during shifting.  They spend =
almost all of their time closed.  These valves are not intended to be =
the primary pressure regulation and would not function well in such a =
capacity. They only limit peak pressure but do not do so with a high =
level of accuracy or control ability.  They would also be highly =
inefficient if used in this manner, as the turbo would be producing =
continuously higher back pressure than needed.  The turbo would be short =
lived and your fuel consumption would suffer greatly.
> > =20
> > The wastegate issue is a much bigger question but the short answer =
is that yes, you probably want/need one.  The only exception might be a =
large turbine turbo that is sized so big that the max boost was only =
achieved at WOT operating conditions.  Even then, you would be limiting =
the usefulness of your turbo at altitude because if it were sized for =
WOT at sea level, it would not be very useful at altitude.  If sized for =
WOT at altitude you could use throttle to control boost down low, but =
you always run the risk of overboost.  Similarly, a fixed exhaust bypass =
would allow a smaller turbo to be used in the same manner but with less =
efficiency and shorter life.  I have experimented with my turbo in this =
configuration.  By removing the flapper valve from my wastegate and =
creating a fixed bypass I was able to run at WOT and have approximately =
the boost I wanted, but only at a very specific altitude.  Any higher =
and boost drops off precepitously.  Any lower and throttle is needed to =
control boost.  There is not much of a sweet spot as the natural =
variations in conditions created a oscillating situation that is simply =
not tolerable.  But for maximum benefit from your turbo, longest life =
and efficiency there is no substitute for a wastegate of some sort.
> > =20
> > Dave Leonard
> > N4VY, Turbo Rotary RV-6
> > =20
> > On Thu, May 7, 2020 at 2:47 PM 12348ung@gmail.com =
<flyrotary@lancaironline.net> wrote:
> > Can anyone help me with the following?    With a turbo, can I just =
use a pressure relief valve and negate the wastegate totally??    =
Looking for simplicity and weight saving.   Neil.
>=20
>=20
> --
> Homepage:  http://www.flyrotary.com/
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