We are designing a new airframe, everyone says that we are mad
designing a new airframe and developing a "new" engine for it, but
I think by doing it that way we have the chance to design an
airframe that has the cooling ducts etc needed for the rotary,
whereas previously rotaries have been placed in existing airframes
and then tried to cool them.
That is is going to be awesome. What airframe is
it going in?
Dave Leonard.
Cheers
Dave. Will stick with the turbo(s) then.
We are
aiming for 350hp and we know that can easily be cooled,
but the engine guy is confident that with the right
ductwork then a reliable 700hp is possible - but I suspect
that the fuel burn would be horrific.
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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