Greetings Gentlemen, I am quiet concerned about the ending of Mazda
rotary production and would like to see the Mistrel type av engine
fitted with a compound turbo system as per Pauls' CAD drawings.
Nothing short of brilliant!
We have just finished price negotiations on a Seawind 3000 incomplete
amphibian kit which we expect to take delivery of next month. We
will be
installing a 20b Mazda on it with a compound turbo system. Yet to be
engineered. Quality reference from anyone having the needed
knowledge in
turbine sizing/design would be highly appreciated.
All the manifolding/mountings will be scratch made in house. We have
located blade producers to handle blade assemblies. I grew up in a
family run machine shop and have 25 years as a Plant Engineering
Technician. Efforts are now moving forward on obtaining ample funding
for an additive machining center to produce honey combed interior shaft
assemblies and end covers to further reduce weight and bring production
costs down. 100 pounds of Monel reduced to 27 pounds of shaft leaves a
lot of time and material on the floor!
We also have a huge existing residential market use for an affordable
45 hp rotary with a blow down turbo. Which we will not disclose for
engineering with out an NDA. $5,000 for an Axiro is more than a bit
much!
Cheers Ya-All, Michael Nash
Michael, A word of warning on the seawind, they are a real dog to fly.
Having that engine up there on the tail is a bad idea, they suffer
badly
from gyroscopic precession when rolling into the turn. A good friend of
mine here killed himself trying to take off from a lake, he hit a boat
wake (not a big one) and it porpoised and dove in killing him. They can
only handle a very small choppiness on the water. I flew it a few times
and boy did it need a lot of rudder input to co-ordinate in a turn.
Changing power settings on final for
landing was a disaster, the pitch changed dramatically with
throttle
change. Just my 2 cents worth here
Michael. Chris in NZ.
With the CG that high I can see how that might happen. Any significant
impact at water level will cause a pitch down.
Paul Lamar
Thank you for your informative words...they have in fact pounded 15 of
these into the ground. The slowed prop does in fact impede airflow over
the elevator and rudder control surfaces particularly on final. We had
seriously thought about moving the 20B down into the aft fuse and using
carbon fiber drive shafts and magnetic couplings for low friction loss
to solve the GG issue. The high speed wing lacking lift is the other
demon. A Retractable hydrofoil to keep the nose up and clean might
help.
Thank you for the "Heads UP" You caring words did not fall on deaf
ears.
I think we will take it to the company that is trying to sell a
certified version Seawind and let them work to save their bacon. I
won't
mind helping them work it out especially if it saves lives down the
road.
Respectfully,
Michael Nash in Virginia
I would lengthen the hull. You need more buoyancy forward.
Paul Lamar
I can't speak to this design specifically but the high thrust line of
this style of aircraft scares me silly. The most common time for an
engine failure is take-off. A high thrust line like this tends to push
the nose down during high power applications which must be compensated
for. On take-off and initial climb you are at low speed, high A of A
and close to the surface. If your engine loses power for even a second
it can be enough to take that thrust line (nose down moment) and
reverse
it into a very high drag line (nose up moment). This puts you way past
the critical A of A where you have no chance of recovery, I knew a
couple of people who sadly learned this in the last few seconds of
their
lives.
John Gibbons
Interesting thoughts as to the Seawind. I remember it at the Oshkosh
seaplane base. It came in with 4 people... left with one. It just
can't get out of the water well. Perhaps some of you remember the Air
Shark.
Much like the Seawind, it tried to be "fast".. In fact, may still
hold
the speed record for a single engine monohull amphibian of over 200
mph., but..
it too came in to the seaplane base to prove it's worth. It was
eventually beached and trailered back to the airshow. Couldn't get out
of the water.
It of course no longer exists. Amphibious monohulls of a smaller
nature
are a compromise. The engine has to go somewhere on top... usually
a pylon.
The Lake Amphibian is I believe the only certificated of that
genre. The
bigger monohulls of course aren't as affected by said thrust lines with
the engines in the wings. The Grumman Goose and Mallards out there
etc... and even the twin Seabee's. These attempts at faster
amphibians
(personally), just don't have enough boat under them. The
compromise to
being faster. (?) It's always (The Seawind) been a beautiful bird...
and fast. Just probably
shouldn't be an amphibian. One to watch perhaps is the French Lisa
Akoya... Basically, a mini Seawind. (with "Seafoils" instead of a
stepped hull) They too are struggling for certification as an
LSA. Some
might say any aircraft can be a widow maker, but.. amphibians given
their versatility and use in water likely score right up there. Good
luck with your Seawind Michael.
Bruce Buksyk
Hi Guys,
I'm adding my words of support to those who are adding their words of
wisdom of using an extra dose of caution for known problems in aircraft
that are flying out there, and thoughts of both improving existing
designs of aircraft and engines, be cautiously aggressive. Those
are not
mutually exclusive terms or traits to follow.
Just as it takes many ingredients and skills to make something simple
like good ice cream, it takes many, many more to make a good, but very
complex, safe engine/airplane combo, more input from everyone directed
into making these projects safer will benefit everyone, present and
future. For those who don't understand the relevance of this analogy,
World famous Blue Bell Ice Cream of Brenham Tx. Just this week
accidently killed three customers because of a very minor error in the
manufacturing process of a well proven product.
Let's all of us do everything possible to help those who are doing all
they can to make better safer aviation products.
Paul, Thanks for the work you are doing. What time and days are your
forums at "Sun and Fun" ?
Fly Safe,
Larry (Flash) Gordon
Houston Tx
My schedule is :
Wankel Rotary Engines in Experimental Aircraft
Tuesday 1:00 room 10
Multi Strike Capacitor Discharge Ignitions for high RPM Wankel rotary
engines
Wednesday 1:00 room 10
Universal Motor Mounts for Mazda rotary engines.
Thursday 1:00 room 10
Paul Lamar
If you want a twin engine composite amphibian, look at this one:
http://www.gweduck.com/
I would absolutely love to have one of these!
Steve Brazil
Steve,
What about building a kit version of the Dornier Seastar
<http://www.dornierseaplane.com/> scaled down to a
six seat with twin centerline Mazda 20B engines in place of expensive
Turbo-Prop engines?
Now that would be one fine design, and cost would not be prohibitive...
G. F. Curtis Jr.
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