Burt Rutan's Model 375 SkiGull Amphibian

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http://www.flyingmag.com/news/burt-rutan-releases-details-his-new-aircraft-design?src=SOC&dom=tw

Burt Rutan Releases Details on His New Aircraft Design
By Bethany Whitfield / Published: Mar 12, 2015
Related Tags: News, Aircraft
Burt Rutan New Design
Burt Rutan recently unveiled preliminary details about his brand new aircraft design, a rugged two-seater outfitted with a retractable ski system that will allow the airplane to operate in rough waves around the world, both in fresh and saltwater alike.

Aptly named the SkiGull, the airplane will be built of composites or titanium — no aluminum — in order to allow operation in the harsh environment of seawater. It is projected to have a cruise speed of 170 knots and, according to Rutan, should have the range to make the trip from Hawaii to California without ferry tanks.

“Imagine going to snow fields anywhere there is around 400 feet of relatively smooth snow, or to a dirt patch right at Puma Punku, or any part of the Amazon, including the tiny rivers that feed it,” says Rutan. “Imagine doing an eight-month exploration trip around the world without ever going to an airport.”

The SkiGull has not yet flown, but Rutan says that if it does he will use it to travel the world with his wife, Tonya.

Rutan, who retired from the aerospace company he founded, Scaled Composites, in 2011, has been working on the design for the past few years. It is also the subject for an upcoming documentary about the legendary aviation innovator, titled Looking Up, Way Up! The Burt Rutan Story, which is currently under development by the award-winning team behind the film SpaceShipOne.

The team has launched a grass-roots fundraising campaign on kickstarter.com to fund the new film, and has currently raised more than $37,000 of its $80,000 goal.
 

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Fascinating...ferry distance between California and Hawaii is 2,400 nmi (without reserves)(!)
Titanium won't be cheap.


I was expecting a small airplane, maybe even an LSA. This is not the case obviously. Who's going to buy this?
Don't get me wrong, i love Burt, but this is weird. I guess we need to wait for more details, in due time.
By the way, if he really wants to sever the need to go to airports, he needs engine(s) that run on Jet-A / Diesel.
 
AeroFranz said:
Fascinating...ferry distance between California and Hawaii is 2,400 nmi (without reserves)(!)
Titanium won't be cheap.


There may be some hints in here....
https://www.youtube.com/watch?v=2OZQ-9Nd76g&spfreload=10
 
I remember seeing this. There were indeed a few hints. AFAIR, he was trying to use a loophole - something to the extent that if the air vehicle has high aspect ratio wings, it counts as a glider and you don't need a pilot's license. I never got the impression that he was planning on designing a large aircraft. Maybe the very long range comes from using the high aspect ratio wings? In that case he's not going anywhere particularly fast. Bladder volume might be the limit on range, more than anything.
 
I think the range quoted in the article above may be mistake - almost the exact phrasing is a bullet point Rutan uses to talk about Boomerang.
 
Extremely interesting... Thanks for sharing.

I could be wrong of course (Given Burt's previous involvement with things that fly "Up, Way Up!"), but when reading the article I fell under the impression that the SkiGull was primarily a water-based vehicle... Something that glides over water, maybe hardly touches it, but not an aircraft proper.
 
Grey Havoc said:
A WIG in other words?

Well, yeah... That's kind of what I had in mind. A cross between a WIG and a jet-ski... But of course I could be very wrong. After all, Burt is the undisputed king of the unexpected in flying!
 
Burt lives in Idaho, right on a lake. It makes sense for him to have a seaplane. however, i believe his area is up high in the mountains. It would make sense for him to have a vehicle with a high ceiling. I have no evidence beyond this, but i think it's going to be a conventional (non-WIG) aircraft. WIGs can fly out of ground effect, but not efficiently.
 
Tend to agree, because there are other ways of getting an airplane out of the water and into the air that carry smaller aero penalties.
 
Maybe it's going to be a hybrid airplane? High aspect ratio wings to fit solar cells with a conventional backup engine?
 
You can see a lot of the features of the design from stills I took from the video of Burt talking about the design.


You can see it has a high aspect ratio wing with a T-tail and the tandem cockpit is built into the main support for the wing. It has sponsons for balance in the water, similar to Dornier's designs.
 

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It now has a wiki entry: http://en.wikipedia.org/wiki/Rutan_SkiGull
 
Is it me, or are there really two engines (PBY-style)? also, i can't tell if the aircraft has a side-by-side layout, or the transparencies aft of the wing pylon are for the passenger seat. Looking at the pictures, i'm inclined to believe the latter, but that's a really weird layout for a GA aircraft.
Maybe Tonya Rutan nags Burt so much that he felt the need to segregate her aft by design!
j/k, i'm sure she is a wonderful person...
 
What's up with the microscopic text? I've been seeing that a lot recently.
 
Sometime people forget to check their work for a bad Cut&Paste (I have been an offender in this).
 
Oops...I think it's happened to me in precisely that case (cut and paste), and for some reason the font got shrunk from the original. If i don't double check my post it stays that way.
 
First Rutan aircraft ever with wing struts? (I don't count inter-wing struts in a biplane/tandem wing.)
 
Rutan talks about his SkiGull in this video:

https://www.youtube.com/watch?v=CatlUfYcG9Y

I only watched ~15 mins worth, but some points from the video:

- It has significant suspension ("about 28 inches") in the struts / skis to make water landings far smoother than normal seaplanes.

- Stall speed is about 40 knots.

- It's meant to be able to be landed on open ocean, beaches, grass, snow, dirt, rough fields and runways (each ski has a few low profile wheels).

- At 13-16 knots, a pneumatic system lifts the aircraft up out of the water and onto the skis.

- It's completely made of titanium and composite; anything that isn't (eg, the single engine) is an LRU.

- Due to it's low drag and high aspect ratio wing, it's range will be around 4500km ("Hawaii to Idaho")

- Max cruise speed (throttle at 75-80%) 180 knots @ (roughly 18,000-24,000ft)

- Approximately 60 miles per gallon of fuel

- It's going to have it's first flight in the next 6 weeks, with Rutan flying it non-stop from (dunno) to Oshkosh Air Show.
 
Dragon029 said:
It's going to have it's first flight in the next 6 weeks, with Rutan flying it non-stop from (dunno) to Oshkosh Air Show.

Most likely from Coeur d'Alene, Idaho, his new home for the past three years or so.
 
I assume the long-haul nonstop flight won't be the actual first flight. That would be rather reckless off an untested aircraft of novel design.
 
From what I gathered from the statement it won't; the first flight will be in 6 weeks, but I think that leaves him a month prior to Oshkosh for preliminary testing.
 
That makes sense. I wasn't sure when Oshkosh was scheduled.
 
Something completely different (mentioned at 15:10) on the SkiGull is the addition of two 12 hp 70 lb thrust electric motor powered folding propellers mounted out on the wing leading edges to be used for water taxiing and docking, takeoff assist power, and emergency flight power sufficient to keep the airplane flying if main engine power is lost. These motors have enough capacity to power climb for 2 1/2 minutes or 5 minutes of level flight to allow for controlled flight to a landing.


The batteries are lithium iron and can be charged by the engine alternator, windmilling the motor propellers, or solar cells.


He says near the end of the interview that his goal is to finish the airplane in six weeks and there is a 50% chance that it will be at Oshkosh.
 
some quick calculations:


4,500 km = 2,430 nmi
@ 180 kts = 13.5 hrs flight time


I dunno... this figure of 180 kts max speed seems a bit sporty to me. Anyway, even at this speed, it would take 13.5 hours of flight time to cover that distance.
Assuming 60 mpg = 52 nmi/gal
that's 47 gal of fuel, or 280 lbs of avgas.


figure one passenger plus fishing/camping gear = 220 lbs
280 lbs of fuel
An empty weight fraction of 50-60% (composite is lightweight, but this is a seaplane with what looks like several unconventional additions, thus comparatively heavy)


TOGW =~ 1,260 lbs, which i believe is around the max for LSA.


Of course i could be totally off. I think he's designing a two-seater, so an alternate load would be Burt + Tonya = 330 lbs
Assuming the same max TOGW of 1,250 lbs
Empty weight = 750 lbs
Camping gear = 50 lbs
Fuel = 120 lbs


The resulting range is still in excess of 1,040 nmi, plenty for anyone, really.

edit: ok, i just finished watching the whole thing. He says the engine is a Rotax running on Mogas (912? 914?)
He didn't want to be limited by LSA rules, so his aircraft might be quite heavier than i thought. He must be using some loophole in certification, because at age 72 (and having undergone heart surgery) he probably can't get a regular pilot license.
He also clarified the quotes on fuel consumption. He's probably not doing 180 kts and getting 2400 nmi range.
Finally, is that me or this seems like a huge FU to John Karkow and the Icon people?
 
AeroFranz said:
The resulting range is still in excess of 1,040 nmi, plenty for anyone, really.


I was going to say that it definitely exceeds bladder range. For me anyway. ;)
 
Stephen Trimble said:
Burt Rutan has just unveiled the design of the SkiGull, a wingship/seaplane, at #OSH15.
Source: https://twitter.com/FG_STrim
 
And here's an attempt at enhancing the photo too. Of course I cannot guarantee that I got all the proportions exactly right but it gives a general idea.
 
I've removed the pics as I mistakingly designated the type as the "Model 372" (as designated in early articles) while the correct designation for the design shown is Model 375-12 (as proved by this new picture found on the web).
 

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The modified files:
 

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Wow, thanks for the pics. The first one really gives it scale, as it is smaller than I thought it would be.
 
I'm surprised that no-one has mentioned it here already, but Burt Rutan's SkiGull had its first flight yesterday, 24 November 2015.

According to Burt Rutan himself: "... the 47th new type of manned aircraft designed by me or produced by one of my companies, has now flown! Just in time, since we got our first North Idaho snow just hours after the flight.

While I do plan to continue designing new airplanes, the SkiGull is the very last airplane that I will be personally involved in building. I built SkiGull in my garage starting 20 months ago and it was a grueling exercise for an old guy in his 70s.

(...) Yesterday our test team preflight briefed the first flight, took off from runway 06 at KCOE, flew for 1.8 hours and landed back on 06. (...) All maneuvers on the card were performed on this first flight."

The complete article can be read here, on the EAA site.

Burt Rutan's current Facebook page "Looking Up, Way Up: The Burt Rutan Story" is here.
 

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