All Things Aviation Related

[Seahawk]

The numbers, especially fuel economy, are staggering.

Never heard of it, thanks for posting!

https://www.thedrive.com/the-war-zone/36016/the-potentially-revolutionary-celera-500l-officially-breaks-cover

https://www.ottoaviation.com/

Originally Posted by KNS

There have been a lot of advances in material science, prop design and engines. 60ft is interesting. That is Global Hawk territory. I managed the Navy's version. Lot's of challenges.

[Dantilla]

Originally Posted by Seahawk

The numbers, especially fuel economy, are staggering.

Never heard of it, thanks for posting!

Chit chat about this has been on the aviation sites for a while.
It has been seen in tests recently, but they've kept the lid on any details until now.

Some advance aerodynamics predict astonishing numbers, but the laminar flow necessary is easily tripped up by small discontinuities like door handles, antennas, even the small bump around window edges or imperfect skin contour.

Not a short-field craft. Will most likely need long runways.

I hope they can pull I off.

[svandamme]

if you look at the best long distance flyers so far.. they all had turbines.. for a good reason.
piston props loose efficiency at altitude , turbines gain efficiency at altitude..

And pusher props.. work better with canards... counters the stall issues
Where's Burt Rutan when you need him!

[crustychief]

looks like an f18 belly tank/glider wings/j-3 tail feathers. cool! Might be a candidate for a scratch built scale RC model.

[KNS]

Originally Posted by svandamme

if you look at the best long distance flyers so far.. they all had turbines.. for a good reason.
piston props loose efficiency at altitude , turbines gain efficiency at altitude..

True but pistons have far cheaper operating costs. Possibly one of the reasons direct operating costs are so low.

Even the ancient B-36 with piston engines had a service ceiling of 45,000 ft.

[john70t]

Originally Posted by svandamme

I don't get it, it's supposed to fly at 60000 feet at 450 knots..

With a V12 Diesel driving that tiny propeller and tiny wings???

I'm calling BS on that.

Laminar wings aren't a new invention.. P51 mustang had wings like that.
Didn't go to 60k feet tho.. despite 3 times more horsepower and an 11 feet prop

I would expect this thing to have vicious stall characteristics without air going over it's horizontal stabs

Agree.
The tube is not a lifting body so all the lift stresses are on the wings.
Probably more efficient at AOA and punching through minor gusts, but IDK. Wing tech is enormous.

But the elevators look like they are the full rotatable kind.
Same as the F-4 Phantom. The flying brick.
(Sorry I forgot the proper name, and Bing is not providing viable non-wikipedia results today, and I won't be steered.)

They are right in front of the prop...

Those huge elevators must create enormous turbulence right in front of that little tiny overpowered prop at high altitude and already low pressure..
It must be like slapping a sheet of cardboard on a fan.

[svandamme]

Originally Posted by KNS

True but pistons have far cheaper operating costs. Possibly one of the reasons direct operating costs are so low.

Even the ancient B-36 with piston engines had a service ceiling of 45,000 ft.

but not 60 000.. thats what they say it will fly at.
and have you seen the hp numbers and diameter of them b36 props?

and are you sure that a prop. reduction gear and variable pitch prop system is lower maint then a turbine???

[Seahawk]

So I sent the link to my partner, Michigan BS in Aero, Stanford MS in Aero.

His rely:

It’s a piston engine / propeller airplane that wants to go M=0.7. I’m going to say don’t invest.

There is some German-bred smoked bratwurst in there somewhere. Not to mention the orca-esque fuselage.

He is German, btw. Now, aero folks are interesting folks but I really want to see the numbers. He sent me some:



I have no idea.

[svandamme]

Originally Posted by Seahawk

I have no idea.

The higher you go, the lower the air density

The smaller the wings, the higher the wing loading

The higher the wing loading, the higher you go, the faster you need to go to keep from stalling.
Also referred to as the coffin corner, because the higher you go, the narrower the performance range of the aircraft becomes.. eg Vmax at some point equals Stall Speed (Vs)

Need lot's of speed to have lot's of air particles over the wings, to get the lifties.





But all that is moot.. because, well , that's wings..
In this case propellers are the bigger problem for altitude, they don't work optimally in low air density.
They need lot's of air particles to get the pull'ies or in this case the push'ies

What can they do to compensate?
More blades
Bigger prop
spin it faster
dual contra rotating
paddle type blades to scoop more air

I see none of that on their Celera 500L apart from more blades..and variable pitch.
But It's still a relatively small prop for such a large aircraft.

True, pusher config is low drag.. so the plane can do with lower thrust at lower altitudes.. The Rutan LongEZ and VariEze are super performant airplanes because of that , they go faster, with much more range then comparable pull prop Cessnas or whatever plane , despite having the same Lycoming 200 or 230 engines..

But the pusher won't fix anything higher up... drag isn't the main concern FL450 or FL600, Everybody wants to go high for Long distance to avoid drag.


But they use jet turbines to do that.. not propellers!



The official highest altitude for a manned prop plane, was in the 30ies..
56000 feet

Lot's of wing.
gutted for weight
Look at that prop!



NASA managed 100 000 feet with the Helios
So To fly that high
with a propeller

The higher you go, the lower the wingloading should be
Huge wings
Low aircraft weight
motors/fuel that weighs very little

NASA did FL 960 with the Helios, with propellers..
Unmanned.



Spot the difference with that Otto thing.



The way the Celera500 is shaped.. with them tiny wings....
It would have to go much faster then 450 knots to manage FL600.
And I doubt that tiny propeller probably can manage 450 knots at FL450

It just doesn't add up one way or another.


So
It can't go fast enough
it doesn't have the wings for it
and the way it's shaped, aft CG, no air blowing over the elevators..
it will probably stall real fast, and recover quite poorly

[svandamme]

High altitude research plane

Those are high altitude props, so they do look similar to the Celery 500.. But they look much bigger to me ..
the props have twice the diameter of the fuselage.. and they have 2 of them




And look at the wings on that Grob (sailplane manufacturer)



EDIT, apparantly that Grob strato is the current record holder for FL600 manned pisto/prop flight

https://www.instagram.com/p/BvrBvCLFfKX/?hl=en

On this date in 1995, the Grob Strato 2C completed its first flight.
The Strato is completely insane.
Constructed from carbon fiber, its wingspan is greater than that of a Boeing B-52 Stratofortress, and it‘s equipped with 19.5 ft (5.9m) diameter propellers that turned at just 650 rpm.
It had a staggering ceiling of 78,740 ft (24,000m), a maximum unrefuelled endurance of 48 hours, and a massive 11,246 mi (18,100 km) range.
You'd think that an aircraft that can achieve such incredible performance would be equipped with a pair of huge turboprop or turbojet engines.
But in fact, the Strato used the same basic engines as a Beechcraft Baron...two Continental TSIO-550 piston engines that produce a relatively meager 402hp each.
Granted, these engines were modified.
The standard turbocharger was removed from each engine, and like a Honda Civic in Southern California, an absurdly large compressor (from a 2,750hp PW127 turboprop as found on ATR-42 and ATR-72 turboprop airliners) was installed.
But despite the huge compressors, the basic engines were the same as those found on the Cirrus SR22 and Beechcraft Bonanza, and the compressors served only to cram as much air as possible into them to maintain horsepower at altitude, as opposed to cranking the horsepower to absurdly high levels.
All of these efforts were intended to carry a couple of scientists and their equipment to high altitudes, where they could conduct atmospheric studies.
But despite setting a world altitude record for manned piston-engined aircraft, cost overruns occurred and not all performance expectations were met.
Accordingly, the Strato made only 29 flights before being permanently retired.
Fortunately, the good people at Grob have preserved it at their airfield in Mindelheim, Germany for future generations to see and appreciate.
So if you ever encounter one of the people at Grob who made this happen, please buy them a beer as thanks for not scrapping it. ⠀

[KNS]

Many unanswered questions. The aircraft pictured is a test aircraft, are the numbers claimed for the test aircraft or future, production aircraft?

Will production aircraft have a different propeller design?

Lots of concept aircraft with revolutionary designs have come and gone over the years, only a very few have gone into production.

[svandamme]

I wouldn't even call this one revolutionary..
It doesn't have anything that hasn't been done before..
laminar flow wing : P51
pusher prop?? been doing those since the very beginning of aviation
diesel? had them in the 20ies
fuselage shape? nothing fancy there
construction materials?? Rutan
The propeller? not new either..
it's all been done before.

Just the performance claims are revolutionary.. But nothing to back those up.

I bet if they scaled up Rutan's LongEZ they would have a better plane then the celery 500L

Look at the Beechcaft Starship , a Rutan design.
Not a commercial success, but a great plane nonetheless




Scale that up even more.. and You'll probably get the same performance as the Celery 500.. with better flight characteristics (lower stall speeds , better recovery)

[Sarc]

Originally Posted by Seahawk

Never heard of it, thanks for posting!

I dig it. Looks like a modernized Glamorous Glennis.



.

[3rd_gear_Ted]

The laminar flow of the air over the specific length and shape of the body creates a higher velocity point of air flow confluence right at where the small prop is thus allowing the smaller prop for same velocity. Correct me where I'm wrong.

[john70t]

Even with 5 blades, those must be spinning in an envelope of extensive turbulence.
(elevators+rudder)

[flipper35]

The Starship was a good idea gone bad.

https://airfactsjournal.com/2018/01/why-the-starship-was-such-a-disaster/

This one, may or may not be all it is cracked up to be. I will believe it when I see it. But a recip engine can go a long ways on fuel. Voyager wasn't even an oil burning piston engine.

The Raptor is one that might me reasonably efficient.

[Rinty]

The Starship was a good idea gone bad...flipper35

Nice to read a McLellan article again. Thanks for posting.

[Seahawk]

The jet folks here may be interested in this. Excellent videoos, btw:

https://www.thedrive.com/the-war-zone/35947/navy-f-a-18-squadron-commanders-take-on-ai-repeatedly-beating-real-pilot-in-dogfight?utm_source=pocket-newtab

Don't feel bad, here is a snap of the first autonomous helo UAS landings I sponsored:

[Dantilla]

Originally Posted by flipper35

The Raptor is one that might me reasonably efficient.

In my opinion, the Raptor has zero chance of meeting its goals.

For those unfamiliar, the Raptor is the brain child of a guy with a computer tech background, who thinks his ideas will revolutionize aviation.
Wide, comfortable cabin, pressurized, air conditioned, supposed to go very fast, very high while sipping diesel fuel.
A 3.0L Audi engine is the base.

Great idea, right? The problem: There has been no actual engineering. The entire project has been done by "That looks about right".
He has had a couple test pilots flee the program. As problems are found, they have been fixed with Band-Aid type changes, often using methods contrary to long-held aviation standards.

The two biggies:
-The Redrive. Power from the engine to the propeller is transferred through a couple wide rubber belts. Think funny car supercharger belt.
BUT- The engine is on your typical rubber engine mounts, while the prop shaft is rigidly fixed to the airframe. the sprockets and belts are not fixed in relation to each other. Experts have chimed in that this will never last long. During ground testing, several parts have already needed replacement.

-The turbos. due to the high altitudes necessary to achieve the speed/range goals, there are two turbos in series. To do this properly, the thermodynamics must be calculated with precision. With a lower-pressure turbo feeding the second higher-pressure turbo, they must be two different sizes. Both turbos in the Raptor are the same. Another forum discussing this has a long explanation how the Raptor's current turbos will create massive back pressure, overheating the exhaust valves in short order.

Current empty weight is over 1000 pounds more than projected, and very close to the projected gross weight. So instead of five passengers in air-conditioned comfort, just the pilot and a bit of gas, and it's at maximum weight.
That's the result of Band-Aid fixes on top of Band-Aid fixes.

Ailerons were very sloppy. Test pilot could hold the stick all the way to one side, while another guy at the aileron was able to move the aileron through its entire range.
Pulleys in the aileron system were bonded to the belly skin, and the skin was flexing instead of moving the ailerons.
The fix? A steel plate bolted to the belly under the pulleys to stiffen that area up.
Anybody with an aviation background would know to mount control pulleys on solid structure like stringers or bulkheads- Not just belly skin.

And the skin is at least twice as thick as it needs to be. Carbon is light, right?
Between the extra thickness, and adding steel in several places as Band-Aid fixes, the airplane is severely overweight.

Where are we now?
Taxi tests. Lots of taxi tests. Down the runway, picking up speed.
So far he has had it up to 90 knots, and it's still on the runway.
this thing will need long runways, and excessive speeds for take-off and landing.
A few months back, a major rocking motion bounced the airplane enough that it damaged the landing gear. Ailerons were flopping, causing the wings to begin a fluttering motion.
Ailerons not solid, landing gear not able to withstand the equivalent of a rough landing.

The good:
Got to admire the guy's tenacity. So many buy a pre-fab airplane kit, with easy to follow step-by-step instructions, and still do not complete their project.
This guy started with just an idea, and has made it happen. Wow. Congrats.
I just wish he would listen to those that have gone down this road before.
Also- He posts a new video twice a week showing his progress. All the world can see his successes and failures.
But- Whenever somebody with expertise points out a possible deficiency in the comments, he blocks them, instead of listening.

Some say it will never fly.

My prediction? It will fly, poorly. It will never come close to its projected performance, and it will never be a commercial success.

I hope it gets back on the ground, safely, before the turbos roast the engine and the drive belts disintegrate.

[Ryan_Cunningham]

Originally Posted by Seahawk

The jet folks here may be interested in this. Excellent videoos, btw:

https://www.thedrive.com/the-war-zone/35947/navy-f-a-18-squadron-commanders-take-on-ai-repeatedly-beating-real-pilot-in-dogfight?utm_source=pocket-newtab

Don't feel bad, here is a snap of the first autonomous helo UAS landings I sponsored:

I'd like to watch the entire 5 hour video but around 5:15 he described what was clearly a 2 circle fight as a 1 circle fight leads me to believe the commentary isn't going to be very valuable.

That being said, most computers can do most things more efficiently than humans. It's certainly that way with autopilot, magic carpet, and in this case 1v1 ACM. That being said, large force employment like a 12v48 would probably be different. But who knows.

My horse has been put in the stable, I think there'll be pilots in cockpits through at least gen 6, but time will tell.

***EDIT***

Fast forwarded to the end to see what the actual pilot was flying, a low cost VR trainer is a poor substitute for our high fidelity FMS's. I think that certainly didn't help.