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The rotary has essentially the same losses with altitude as any engine. There are a lot more considerations than just SL horseposer and weight but IMHO you will be dissapointed with the performance of any engine at FL250 if you do not have some sort of forced air induction. If you are going to bother to go that high on a regular basis, you may as well put on a turbo to really take advantage of the higher TAS that otherwise will be out of reach.
I fly mine right up to 17.5K whenever I have a reason to do so, but without the turbo it would take too long to get there and there would be no net benifit. Normally aspirated engines really suck above 10k.
Dave Leonard
A question from me - considering we
will be using a 4 rotor engine which will produce around 350hp
without a turbo at sea level - is a turbo really needed for an
aircraft that is
MTOW 2250 lbs
Flying to FL250
or would a 4 rotor/350hp engine be
sufficient even with the loss of power of a normally aspirated
engine at altitude? (which I vaguely recall is less of a power
drop for a rotary engine than a piston engine).
Hi Neil,
I started with the stock turbo knowing it wasnt
quite rite for the job, but hey, its came free with my
engine. It performed pretty well but only lasted about 100
hrs. Since then I have been with various iterataions of the
TO4 in a modified stock turbine housing. Those have performed
very well but are not industructable. Prolonged periods at
Peak EGT will melt them too. I have over 600 hrs on my curent
turbo becuase I keep it either rich or lean of peak and the
TOT less than 890C.
I recall the exact size of my radiator,
20"x22"x3" rings a bell. It is all detailed in the archives
and on my website. (which is in dire need of an update).
Dave Leonard
www.rotaryroster.net
Dave,
Still trying to get around to
fitting a turbo, possibly next lifetime the way I am
going. What turbo did you end up fitting, and what
size cooler? Neil.
I agree with Marc. A proper single
turbo will be more efficient, more reliable, and
much easier to install. Sequential turbos are most
helpful to minimize turbo lag in automotive
applications. Stock one or two-piece apex seals are
plenty (even preferred) for modest boost levels (up
to 150 hp per rotor or so).
The rotary will not burn less fuel
than an 8 cyl aircraft engine at the same output.
It will burn more, but not an excessive amount
more.
Dave Leonard
That
does not sound to me like a suitable aircraft
configuration.
A single turbo would suffice, the
controller/wastegate would dial in the boost
needed to maintain SL pressure in the manifold at
any condition, there isn't a reason to 'overboost'
the engine. Too complicated and
unnecessary-especially all the hot turbo piping
could get very messy.
Is the engine builder using ceramic rotor tip
seals? Good idea for boosted engines.
MW
-----Original Message-----
From: Rotary motors in aircraft
Sent: Wednesday, September 04, 2019 2:00 AM
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: The ultimate question...
Was just talking to the engine builder and the
answer to one question also answered another -
The reason that the engine will have two turbos is
that they are set up sequentially - the first one
operates as a turbo normaliser to 500 rpm above
cruise rpm. Once the throttle is opened past that
point for takeoff/climbout the second turbo kicks
in to more power.
That also explains the fuel efficiency at cruise -
only a small turbo is operating to provide turbo
normalisation. Hope this makes sense!
On 4/09/2019 11:21 am, Kent Bedford kbedford@alphalink.com.au
wrote:
> Kind of strange how it worked out, but when
we made a small change to
> the design that gave a tangible benefit we
suddenly found ourselves
> with room for an extra 40 gallons on top of
what we already had - 90
> gallons should be enough for range to be
governed by bladder size
> instead of fuel tank size.
>
> On 4/09/2019 6:08 am, Charlie England ceengland7@gmail.com
wrote:
>> On 9/3/2019 2:31 AM, Kent Bedford kbedford@alphalink.com.au
wrote:
>>> ...if someone has an about 450hp four
rotor + turbo engine with
>>> effective cooling, and resolves the
torsional vibration and
>>> resonance issues (which will partly
be resolved by having four
>>> rotors anyway), are there any other
foreseeable likely or possible
>>> issues that may need to be overcome
to successfully operate it with
>>> a good 500hp-rated PSRU like a
Ballistic or similar?
>>>
>> Figuring out where to put the fuel,
unless you're talking about a
>> time-to-climb record attempt or Reno
racer. Any usable a/c at that
>> power level may require your own
refinery.
>> Charlie
>>
>>
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