Cobalt Aircraft

[IO540]

What do people think of this (http://www.cobalt-aircraft.com/)?

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.

[Maoraigh1]

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

[IO540]

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.

[Jan Olieslagers]

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.

[IO540]

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.

[mmgreve]

@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.

[Jan Olieslagers]

@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.

[Genghis the Engineer]

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

[IO540]

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.

[Genghis the Engineer]

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 (http://www.darcorp.com/Software/AAA/)); 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

[Rod1]

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

[gasax]

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.

[jxk]

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.

[IO540]

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.

[Genghis the Engineer]

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.

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

[jxk]

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

[Charles E Taylor]

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 (http://aasijetcruiser.wordpress.com/)

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




Charlie

[mmgreve]

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(?)

[IO540]

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?

[kui2324]

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.

[jxk]

An interview with Colbalt designer here at Loop, about 3 minutes in:

LoopTV.Aero (http://www.looptv.aero/LTVCategory186/2247/OSHKOSH2010%E2%80%93MONDAY.aspx)

[IO540]

Very interesting :ok:

At 650k USD (which is sure to rise) it better be damn good, with superb avionics integration etc.

[Fuji Abound]

Hmmm, the problem with a new aircraft like this (on the basis as pitched to be used by the owner flyer) is that it will have to be a fully capable IFR / IMC platform. Whereas in Europe the airways might be empty of GA that is most certainly not the case in the US. However equally at this level that means the aircraft needs to be FIKI and needs glass.

They therefore have some big hurdles to overcome compared with the likes of Cirrus and I suspect they are very unlikely to be competitiors for some time.

[IO540]

Maybe... Cirrus, and Socata and Mooney before them, have managed to sell a suprising number of IFR singles into Europe, in the vast majority of cases with no ice protection.

I think the salesman saying it is a tool for travelling is being less than honest. A tool for travelling needs 100% anti-ice and radar. Without these, your dispatch rate will be down to say 75% which is fine for "business travel" (as in meeting up with chums who you do business with) but is no good for real business travel (pre-scheduled customer visits).

And I say 75% even based on flying VMC on top enroute.

Interestingly, radar is a possibility in the Cobalt. Whether they will realise the value of it is another matter. But if they originally planned it as a jet, radar would have been a must.

European airways are empty of GA because too few pilots have an IR and too few airports have an IAP and most have limited opening hours; not because of lack of aircraft ice protection.

The other thing is more basic: is there really a market between the "SR22" level, and SE turboprops? A lot of salesmen think there isn't and that anybody with $700k can afford $2M. Together with the perceived need for pressurisation, and poor TP efficiency at low altitudes, this is why we see such a big gap between pistons and TPs.

[Fuji Abound]

Maybe... Cirrus, and Socata and Mooney before them, have managed to sell a suprising number of IFR singles into Europe, in the vast majority of cases with no ice protection.


Yes, but Europe is a small market. The aircraft must sell in the US to be viable. Very few Cirrus are now be sold without at least the get you out of trouble anti ice (which is in terms of the airframe is the same system as on the full FIKI model). You can order a 42 without FIKI, but does anyone? Mooney and Socata are sadly no longer producing aircraft. Whether they use it or not I just dont think the owner pilot in the US these days will buy without some form of wet wing and de-ice. In the US at least I think weather radar is less of an issue because the owner pilot would be nearly as happy with NEXRAD, even if it is not quite as good as weather radar. In Europe of course things are very different.

The other thing is more basic: is there really a market between the "SR22" level, and SE turboprops?

I recall a good article in Flying about how difficult it is to establish any new type or, to a greater degree, concept in aviation. Pilot's are rightly both a cautious and cynical lot. We have all seen new manufacturers come and go. The vast majority of potential punters in the market for a single engine turbo prop will buy from an established stable with a tried and tested design even if their product is 40% more costly. The price and concept would have to be very very attractive to persuade people otherwise - and if it were that attractive and that radical then the manufacturer will probably be bust in short order. You cant change physics, and since physics has such a big impact on aircraft design you cant readily change the cost of developing and certifying a radical new turboprop.

The reason Cirrius has been so successful and dominates GA today (and to a lesser extent Diamond) is because they created the illusion they had done something radical, when in fact they had not. They took reasonably tried and tested technology and put it together in a package that could take full advantage of the economies of producing a plastic aircraft. In fact a good example of the risk is that the only radical step Diamond took was to fit diesel engines in their 40s and 42s. To be fair they nearly pulled it off, but it also proves how dangerous taking such a leap of faith can be. (from one who very nearly bought and 42 and is entirely glad to have listened to your and others wisdom Peter!).

[IO540]

More here (http://www.aopa.org/oshkosh/oshkosh10/news/100728cobalt.html?WT.mc_id=100730epilot&WT.mc_sect=gan).

It makes me smile to see the MTOW as 3087lb. The TB20 is 3086lb :)

Maximum takeoff weight is planned to be 3,087 pounds, with a useful load of 1,213 pounds and a full-fuel payload of 552 pounds.

Exactly the same as the TB20 sales brochure, except that no appropriately equipped TB20 has a 1213lb payload.

So they are aiming for the same market, rather than the "four fat Americans" which the DA50 is aimed for.

[lancen]

with 262 hp, at 8,000 ft, I SERIOUSLY doubt they will ever get even close to 245 kts - unless in a pretty significant dive. I believe the plane hasn't flown yet, so think "hype". No great benefit to a canard and I see a lot of interference drag locations.