Cobalt Aircraft
 

What do people think of this?

They give performance only for 75% power but at 75% it doesn't seem as efficient as it ought to be for a canard.

To their credit they don't pull the standard marketing stunt of quoting the TAS at 25000ft - on an unpressurised aircraft.

T.O. distance seems impressive. Doesn't say if ground run or to 50'.

With 350HP, and an MTOW of perhaps 1400kg, the takeoff distance will always be impressive :)

But anybody can stick a 350HP motor into a plane. It's an off the shelf 6-cylinder item, from both Lyco and Conti. One could stick one in my TB20, even. Then, given it has a turbo, you quote a FL250 TAS figure, which will always be well above 200kt.

But that doesn't translate to any worthwhile economy, necessarily, especially as there is no way to fly at FL250 without a mask (cannulas are hard work at FL200).

Very superficially, the fuel burn doesn't seem different to a Cessna 400.

95 litres of 100LL per hour seems VERY hefty, even if you'll do a lot of distance in that one hour. I could not find any figures right away, but I figure a Thielert - Centurion, I should really say - V8 would make do with half of that. I simply can't understand anyone wants to apply a 100LL engine to a new design in 2010.

We've done this one here before. I think that it is very hard to make progress in the USA with a diesel engine, and this won't change for years, at least. And in Europe, only the boldest keenest guineapigs who happily live on the bleeding edge, buying up every computer gadget with v0.001-beta firmware, will go for a diesel after the Thielert fiasco.

When diesels become a proven concept, you will be able to retrofit one. They will be made with mounting points compatible with the IO540/IO550 engines.

95L/hr is a helluva lot but all the "fast" planes burn that, e.g. Mooneys and C400 etc. to get 200kt+.

But with a canard I would have expected a spectacular improvement.

But maybe there isn't one.

Maybe the reason why the Long-EZ etc are so good is because they are so narrow in cockpit area terms. That's an easy way to get economy. Not because they are canards.

@IO540: I think that the SPECTACULAR improvement is that these numbers are quoted at 8000ft, not 25000 - so it is real usable speed here in Europe.

I would be intrerested in to know what the landing distance is. I understand that canards normally like a nice long piece of tarmac, but I have never tried flying one.

Personally I think it looks very interesting, you definitely get a lot of presence for you money as well as the fifth seat.

@mmgreve: I haven't flown any canard either, but I learned canard pilots prefer "clean" runways (normally translating to "hard" runways) because any debris thrown up by the wheels risks damaging the pusher prop normally associated with the canard design.
Also, canards seem to have higher-than-usual stall- and approach speeds (though I wouldn't know why), requiring longer runways indeed.

@IO540: if canards made a spectacular improvement, they'd be all over the place - just like diesels. Pilots are a remarkably conservative bunch, private pilots not the least: they'll only change their preferences if and when they really have to.

Very pretty, but....

- Looking at it in side view, it looks likely to be directionally neutral to unstable

- Reducing the cruise performance to CAS, I get about 195kn at 75% power, which sounds in the right order.

- Whilst I can see the point of double fins to enhance directional stability, I can't really see the point of a V-tail with a canard, there should be no need for separate pitch control to the canard, and all it's going to do is introduce unwanted pitch/yaw coupling.

- Nice to see a 4/5-seater being designed with a sensible payload.

- It may have a good short take-off distance (although I reckon that's 1300ft roll, not distance they're quoting), but with 65kn stall and a canard, it'll eat runway on landing.

- The tiny canard should minimise the known canard gust aggrevation factor, but also will give almost certainly very poor pitch stability and I'd anticipate problems with the longitudinal pitch damping.

- Very interesting, and I'd seriously consider the job of running the flight test programme if anybody wanted to ask for me!

G

They won't get certified with a 65kt Vs, AIUI. The limit is ~ 60kt. The TBM700 got this increased by demonstrating a higher level of crash-proofing.

Interesting input on stability... presumably they are aware of this issue; nowadays everything will have been extensively simulated with CAD.

The limit for single engined aeroplanes certified to part23 is 61kCAS, which is a good point, it would need to be brought down to that (or certified to part 25, which would be prohibitively expensive). Looking at it, the simplest fix to that would be a bigger Canard to milk more from the wing (and at the same time improve longstab).

You can model something like this reasonably readily (not in CAD as such, but there are plenty of other tools); but no sensible engineer would trust that alone, they'd want it wind tunnel testing. Then you'll flight test it and still find out that there was still stuff you'd missed! (Particularly the pitch/yaw coupling would be hard to analyse accurately in the wind tunnel, although a radio controlled model might tell you quite a lot.)

G

Canards and stalling are a bit unusual. In a stall the for planes stall and the aircraft nods. It is very safe, but you have to fly them on unless you want to wipe out the nose gear. The Long-Ez I flew was a very nice bit of kit, side stick, superb vis and 130kn on 100hp, but it needed 700m of black stuff to get airborn and 750 to stop (the airfield was just under 800m). I decided it was not very practical for the UK and did not buy it.

Rod1

I watched an Avanti take off from Deauville last week.

Beautiful looking aircraft but it used not much less runway (well about 500m less) to take off, than the A319 that arrived before it, used in landing!

Difficult to see what real advantages the Cobalt offers over the exisiting competition, let alolne a variety of designs not presently in production but which would notionally be available.

To choose a relatively 'difficult' basic configuration which would doubtless need considerable development (think Beech Starship and not so much its production issues but the flight testing with linkages between canard and flaps etc) seems to be setting a steep challenge.

Why would you need 5 seats? I doubt whether you'd ever fill them and if you did, image all the hassle dealing with 5 different points of view. It was bad enough in a Saratoga trying to decide which type of restaurant everyone wanted to eat at.
Regarding the design I thought pushers and canards had all been disproved when the Cirrus came along. I remember Daryl Stinson giving a lecture and mentioning T tails as being a fashion derived design and they've fallen out of favour now.

I think that if they can achieve an extra 30kt at say FL100-180 (the choice operating level for higher end unpressurised GA) over a Cessna 400 at the same fuel flow, and deliver a FL250 ceiling, they will have a super product.

If OTOH their performance claims are like everybody else's (go mostly out of the window by the time the thing is finished; how many recall the 207kt claim for the DA42?) and in the end achieve just an extra 10-15kt, they will fail.

An interesting angle here is that the Cobalt is retractable. It is the only modern composite design that is retractable. Of course the Cessna and Cirrus salesmen say their fixed gear costs them just 2-3kt (which is obviously bollox) but this design might derive quite a big advantage due to this, not due to the canard.

Why are so many people convinced he's called Daryl, he's Darrol Stinton. (Or at-least, that's how it's written on the cover of his books, and so far as I could decypher his handwiting, on his christmas cards.)

G

Sorry GTE with regard to Darrol Stinton, it's just another design fault:)

Canard Configured Aircraft.

It is really good to see that people with dreams are still prepared to invest!

It might be wothwhile to look at what has been done before?

AASI Jetcruiser Details with Photo

I would be surprised if Hartzell allowed a metal prop to be fitted to a pusher, we will see......




Charlie

Has anyone in here seen the plane in Oshkosh? I assume that it is not just a mock-up as they were planning to have already started flight testing(?)

The other thing which comes to mind is that their 350HP engine variant probably has a zero chance of ever running on any unleaded fuel - short of the "GAMI G100UL" which for reasons unknown is still talked about but nobody is apparently doing anything with it. I wonder if GAMI are asking too much for the patent licensing?

Saw the Cobalt at Oshkosh - still very much a work in progress!

A few pieces still made of ply. Will try and remember to get picture tomorrow.