Mailing List flyrotary@lancaironline.net Message #65187
From: David Leonard wdleonard@gmail.com <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: The ultimate question...
Date: Sun, 8 Sep 2019 09:42:16 -0700
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
That is is going to be awesome.  What airframe is it going in?

Dave Leonard.

On Sun, Sep 8, 2019, 8:53 AM Kent Bedford kbedford@alphalink.com.au <flyrotary@lancaironline.net> wrote:
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.

On 8/09/2019 12:16 am, David Leonard wdleonard@gmail.com wrote:
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

On Fri, Sep 6, 2019, 7:43 PM Kent Bedford kbedford@alphalink.com.au <flyrotary@lancaironline.net> wrote:
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).



On 6/09/2019 1:00 am, David Leonard wdleonard@gmail.com wrote:
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

On Wed, Sep 4, 2019, 3:21 PM Neil Unger 12348ung@gmail.com <flyrotary@lancaironline.net> wrote:

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.

On 9/5/2019 6:36 AM, David Leonard wdleonard@gmail.com wrote:
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

On Wed, Sep 4, 2019, 1:24 PM Marc Wiese cardmarc@charter.net <flyrotary@lancaironline.net> wrote:
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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