For Morgans ...Rotax (x 2)

[Montblack]

Here you go Jim - From NC,

Pusher-Puller Twin-Rotax 582's ...Italian job. <G> <G>

http://www.flylab.it/tucano2ve.htm
TUCANO Delta3 VTW

http://www.flylab.it/tucano2e.htm
TUCANO Delta3 TW

"The Tucano Delta3 TW (twin-engine) represents the successful attempt to
cope with the quite often disagreeable consequences of an engine breakdown.
It has been extensively tested with excellent result."



Montblack

[Ron Wanttaja]

On Wed, 26 Apr 2006 22:42:17 -0500, "Montblack"
> wrote:

>"The Tucano Delta3 TW (twin-engine) represents the successful attempt to
>cope with the quite often disagreeable consequences of an engine breakdown.
>It has been extensively tested with excellent result."

All it means is that you've got twice the chance of having an engine failure....

Ron Wanttaja

[Ian Mitchell]

"Ron Wanttaja" > wrote in message
...
> On Wed, 26 Apr 2006 22:42:17 -0500, "Montblack"
> > wrote:
>
>>"The Tucano Delta3 TW (twin-engine) represents the successful attempt to
>>cope with the quite often disagreeable consequences of an engine
>>breakdown.
>>It has been extensively tested with excellent result."
>
> All it means is that you've got twice the chance of having an engine
> failure....
>
> Ron Wanttaja

And half the chance of it killing you

[Ron Wanttaja]

On Thu, 27 Apr 2006 03:53:17 GMT, "Ian Mitchell" >
wrote:

>
>"Ron Wanttaja" > wrote in message
...
>> On Wed, 26 Apr 2006 22:42:17 -0500, "Montblack"
>> > wrote:
>>
>>>"The Tucano Delta3 TW (twin-engine) represents the successful attempt to
>>>cope with the quite often disagreeable consequences of an engine
>>>breakdown.
>>>It has been extensively tested with excellent result."
>>
>> All it means is that you've got twice the chance of having an engine
>> failure....
>
>And half the chance of it killing you

Mmmmmmm....no. An engine failure in a single-engined airplane requires a
deadstick landing. Bad, yes, depending on where it happens, but the pilot uses
the same skills he or she uses on every flight. An engine failure on a
twin-engine plane puts the pilot in an unusual mode of flight. Yes, a pilot
with current skills and the right training will have a better chance to bring
the aircraft home intact. But in the real world, it doesn't work out that way.
*Any* emergency is bad. Pilots die after engine failures in twins, too.

The Tucano should avoid some of the problems due to centerline thrust, but the
fact is, it has twice the fuel burn, twice the propellers, twice the ignition
sources, and twice the exhaust heat of a single-engined airplane. There are
more things to break, more chances to lose power unexpectedly, more chances to
mismanage fuel, and more things that can start fires.

Two stroke engines are about twice as apt to quit than "conventional" aircraft
engines. The solution is not to use *two* of them, but a single more-reliable
powerplant.

As for those wonder how eager the market is for twin-two-stroke
centerline-thrust airplanes, I just have three words: Powers. Bashforth.
Minimaster.

Ron Wanttaja

[Richard Lamb]

..5 reliable component x .5 reliable component = .25 reliable system.

also, .9 x.9 = .81, just for argument sake.



Richard

[Canal builder]

That's not a complete picture. It just so happens that I have an exam on
Safety, Risk & Reliability tomorrow.

There's a good reason why airliners have more than one engine. The idea is
that they can make it to an airport on just half of their engines. This is
known as redundancy.

So, if your plane has two engines, each with a reliability, r, of 0.9 (
that's a 1 in 10 failure rate, reliabilities are much higher than this in
reality), and only needs one engine to make it to a safe landing site, your
overall reliability will be

Following some maths (let me know if you want a full explanation) we get,

System reliability = 2r - r^2

Therefore reliability = (2*0.9) - (r*r)
= 1.8 - 0.81 = 0.99

So, providing that it can fly on just one engine you have a much lower
chance of walking out of a field you never walked into.

If you are relying on two out of four engines (r = 0.9 again) your
reliability is up to 0.9963.

This does, of course, leave the problem of piloting a plane with imperfect
flying characteristics, but it gives you more time to deal with the problem

Finally if the plane can't make it home on half engines, don't fly it. As
Richard points out your reliability decreases.

Ed

On 27/4/06 9:29 am, in article , "Richard
Lamb" > wrote:

> .5 reliable component x .5 reliable component = .25 reliable system.
>
>
> also, .9 x.9 = .81, just for argument sake.
>
>
>
> Richard
>

[Tim Ward]

"Richard Lamb" > wrote in message
...
> .5 reliable component x .5 reliable component = .25 reliable system.
>
> also, .9 x.9 = .81, just for argument sake.
>
>
>
> Richard
>
Yep. That's why I fly a Schweizer 1-26. I don't believe there has ever
been an engine failure in a 1-26.

Tim Ward

[Morgans]

"Montblack" > wrote

> Here you go Jim - From NC,
>
> Pusher-Puller Twin-Rotax 582's ...Italian job. <G> <G>
>
> "The Tucano Delta3 TW (twin-engine) represents the successful attempt to
> cope with the quite often disagreeable consequences of an engine
> breakdown.
> It has been extensively tested with excellent result."

First of all, let me say, "you are really cruel."

That out of the way, <g> even if it had 69 Rotax 582's, I would not get into
it. The two strokes are not suitable for flight, IMHO. They belong in Sea
Doo jet skls, where WHEN they quit, you can sit and wait for a tow back to
the dock.

If they used two stroke Rotax engines, I might be talked into _riding_ in
one, depending on their single engine service ceiling, and other performance
parameters, with one engine out. The saying about "two engines means there
is always an engine running, to get you to the scene of the crash" holds too
much truth.

I still would not own one, because there still is an engine to keep running,
and now there are two engines to keep running. It sounds like a maintanence
headache, to me.

It sure is an ugly little beastie, isn't it? I though the Italians were
supposed to be known for their sexy, stylish sports cars, and stuff. It
sure didn't carry through to this airplane.

You just love throwing salt into open wounds, dont't you? Shame on you!
;-)

[Ian Mitchell]

Snip "relevent fact"

Don't confuse the issue with facts, they don't want to change an earnestly
held pre-concieved notion.

Ian

[Ian Mitchell]

>" Mmmmmmm....no. An engine failure in a single-engined airplane requires a
> deadstick landing. Bad, yes, depending on where it happens, but the pilot
> uses
> the same skills he or she uses on every flight."

Mmmmm...no the problem is most GA pilots use powered approaches,
particularly flying into controlled airfields during a normal flight. A
"deadstick" presents them with an opportunity for poor decision making.


An engine failure on a
> twin-engine plane puts the pilot in an unusual mode of flight. Yes, a
> pilot
> with current skills and the right training will have a better chance to
> bring
> the aircraft home intact. But in the real world, it doesn't work out that
> way.
> *Any* emergency is bad. Pilots die after engine failures in twins, too.

Yes, usually associated with asymetric control issues. I'm guessing more get
home after a single engine failure than don't.

>
> The Tucano should avoid some of the problems due to centerline thrust, but
> the
> fact is, it has twice the fuel burn, twice the propellers, twice the
> ignition
> sources, and twice the exhaust heat of a single-engined airplane. There
> are
> more things to break, more chances to lose power unexpectedly, more
> chances to
> mismanage fuel, and more things that can start fires.

Fair comment, except that the single engine performance in cruise suggests
that may be a "normal" mode of operation. I think the potential for this
aircraft is in operations over water, hostile terrain. Maritime or forestry
patrol etc.

>
> Two stroke engines are about twice as apt to quit than "conventional"
> aircraft
> engines. The solution is not to use *two* of them, but a single
> more-reliable
> powerplant.

Before I converted to ultralights from GA, I was pretty concerned that one
day the fire would go out and bad things would happen. I never had an engine
failure in GA, and I haven't had one in an ultralight yet either, but I'm
not concerned about it, when you do most of your flying at 500' or less, you
are always noting the location of the best forced landing area, taking the
long way around "tiger" country etc. The problem with conventional 4 stroke
aircraft engines has been weight, and the need to put them into a bigger
heavier airframe. I'm very encouraged by the developement of engines like
the HKS and Warner, as they appear to offer a nice blend of light
weight/power/reliability.


>
> As for those wonder how eager the market is for twin-two-stroke
> centerline-thrust airplanes, I just have three words: Powers. Bashforth.
> Minimaster.

Don't know anything about those, my only comment would be that the problem
may have been a business, marketing etc issue and not the concept in
general.

Ian

[Richard Lamb]

Ian Mitchell wrote:

> Snip "relevent fact"
>
> Don't confuse the issue with facts, they don't want to change an earnestly
> held pre-concieved notion.
>
> Ian

Maybe, so.

I don't get very excited about ugly airplanes...


Now a Pulsar with wing mounted twin 582's?
I'm fool enough to think that'd be sweet.


Richard

[Montblack]

("Morgans" wrote)
> First of all, let me say, "you are really cruel."
[snip]
> You just love throwing salt into open wounds, dont't you? Shame on you!


I had to hurry up, before that sucker closed up! <g>

http://home.att.net/~dannysoar/BelGeddes.htm
Rotax, Rotax, Rotax, Rotax, Rotax, Rotax, Rotax, Rotax, Rotax, Rotax...


Montblack-hearted-fiend, er, I mean, um ...friend. Me friend.

[John Kimmel]

.. The problem with conventional 4 stroke
> aircraft engines has been weight, and the need to put them into a bigger
> heavier airframe. I'm very encouraged by the developement of engines like
> the HKS and Warner, as they appear to offer a nice blend of light
> weight/power/reliability.
>
>
>
>> Ian
>
>
Published performance specs for the HKS:
56HP @5800RPM 4.2gph/.45bsfc.
This will require a volumetric efficiency of 110%. Not bad for an
engine running at 75% throttle. In fact, not very likely.

Published performance specs for the Verner:
63HP(75%) @3750RPM. 2.7gph/.25bsfc Much more reasonable 55% volumetric
efficiency with 75% power, but absolutely astonishing fuel efficiency.
In fact, not very likely fuel efficiency.

Both engines achieve their light weight by running at high rpm with
small displacement, and by using Nikasil aluminum cylinders. Which is
to say, they are race car engines.

Would you rather have a C-85 with 2000 hours TT or a Verner with 600
hours TT? Or a 2 stroke with cast iron cylinders?

I would appreciate it if someone would check my numbers and see if they
come up with similar results.

--
John Kimmel

remove x

"He's dead, Jim."