Quad motor aircraft future ?

[R.Perry]

I had a great conversation today with a guy I have known for years, and has his finger on aviation and what may be coming. The drone as we know it today has taught us many things, one being how to build an affordable vertical take off aircraft that has enough AI technology to make learning to fly it easier than learning to drive a car.
He believes as I do, the next thing we are going to see in aviation is hybrid aircraft built on the quad motor design. My friend is a retired aeronautical engineer and he feels the technology could easily replace helicopters as we know them today.
Helicopters are maintenance hogs, a hybrid quad copter would have a fraction of the maintenance and have a much better safety potential than helicopters especially if they are equipped with parachutes in case of catastrophic failure.
So why aren’t they producing them yet? He believes as I do, ATC. Fill the skies with personal aircraft that just about anyone could fly, and you have an air traffic control nightmare.
The advantages of quad aircraft over helicopters could be substantial, they could get into tighter places for search and rescue, could have longer flight time, crop dusting costs could be cut drastically and would be much safer.
Let’s take a Bell 206 new about 700,000 with limited lifting capacity when fully loaded. Operational costs per hour is between $400.00 and $500.00 per hour. Burns about 25 gal an hour.
Hybird quad copter with four-cylinder engine driving two generators (redundancy) and four AC motors estimated operations costs less than $50.00 per hour. Estimated cost to produce $55,000 to $65,000 depending on avionics.
Program your flight computer for your destination after getting ATC clearance and go along for the ride.
My friend and I think we are going to see it in the not to distant future.

 

[AH-1G]

I would be worried with a quad, what if a motor went out? It's better to have a hex, one motor out you can still fly.

 

[Phaedrus]

 

[clolsonus]

Here is my 2c and why I don't think this is the next big thing for humanity. Traditional helicopters have a huge efficiency advantage over multi-rotors. Traditional helicopters have the ability to autorotate in the event of a power lose and the ability to set down in any small open clearing. I get that parachutes might mitigate this, but if you are tumbling on 3 motors when you pull the chute, you might just end up in a big tangled ball. I give the safety edge to traditional helicopters. These multirotors are 100% fly by wire ... there is no way to make them manually controlled. They are subject to electronics glitches, software bugs, logic/design errors, sensor errors, etc. (cough)MCAS(cough) Then don't forget cost. Owning and maintaining an full size aircraft is crazy expensive. One of the things that hurt the 1950's flying car was that an owner/operator needed something like 7 different gov't certificates because operating it spanned multiple gov't organizations.
This is an intriguing idea ... people and NASA are interested in these things ... but personally, I'm not seeing this going much beyond a few cool prototypes or a few uber rich or uber daring souls. I could be wrong though ... wouldn't be my first time.

 

[PatR]

Passenger multorotor type aircraft will most likely be limited to short range operations as their power/propulsion systems, their lower speed, and limited payloads will not have the ability to compete with either a helicopter or winged (tilt rotor) design for heavy lift, long duration, or high speed operations. Hybrid power systems are terribly inefficient as a combustion engine typically only achieves about 25% from the energy available in the fuel supply. Electric is about 95% efficient but the fuel supply is quite heavy for the duration provided. The adaptation of a hybrid system carries it’s own efficiency barriers.

 

[R.Perry]

Here is my 2c and why I don't think this is the next big thing for humanity. Traditional helicopters have a huge efficiency advantage over multi-rotors. Traditional helicopters have the ability to autorotate in the event of a power lose and the ability to set down in any small open clearing. I get that parachutes might mitigate this, but if you are tumbling on 3 motors when you pull the chute, you might just end up in a big tangled ball. I give the safety edge to traditional helicopters. These multirotors are 100% fly by wire ... there is no way to make them manually controlled. They are subject to electronics glitches, software bugs, logic/design errors, sensor errors, etc. (cough)MCAS(cough) Then don't forget cost. Owning and maintaining an full size aircraft is crazy expensive. One of the things that hurt the 1950's flying car was that an owner/operator needed something like 7 different gov't certificates because operating it spanned multiple gov't organizations.
This is an intriguing idea ... people and NASA are interested in these things ... but personally, I'm not seeing this going much beyond a few cool prototypes or a few uber rich or uber daring souls. I could be wrong though ... wouldn't be my first time.

Sorry, but traditional helicopters don't have and advantage, look at the spec sheet on a Bell 206 for instance, very limited payload, and a huge price tag.
You have a fear of electronics and computers, well don't get on an airliner, most are fly by wire, and the pilots don't fly, the computer does.
Aviation grade electronics has proven very reliable, and most likely any new aircraft will have a redundant system, meaning two flight computers minimum. As stated most will be hybrids with a small gas engine running generators and a battery backup.
The reason helicopters are so costly to operate is due to the maintenance requirements. Sure they have auto rotate if the engine quits or turbine flames out, problem is the two primary causes of helicopter failures is the gear box and the tail rotor failure. So instead of four electric motors, put eight and now you have an aircraft that would be more reliable than a helicopter and tremendously less expensive.
Look at our drones and how cheap they are and their reliability is very high. Having a hybrid means you have much longer flight time, and they could be built to have comparable speeds to helicopters. There is already a hybrid drone that will fly up to five hours.
A drone parachute would be charged so the chute deploys automaticlly if the aircraft rolls a preset number of degrees, say 30 to 40 degrees.
Crop dusting would be a perfect fit for a multi rotor aircraft, less expensive, and better chemical penetration of the crops, especially orchards.
Personal opinion is they would be a tremendous asset to general aviation and some commercial aviation today.


The biggest draw back to personal aircraft in high traffic areas is ATC, they can only handle so many aircraft and maintain safe separation. However for remote areas, I think they would be tremendous.

 

[AH-1G]

..... two primary causes of helicopter failures is the gear box and the tail rotor failure....
I don't know where you got your data from, but that's incorrect. Common Causes of Helicopter Crashes | Hogan Injury
Most accidents are pilot error!
When I was in the army I worked on Cobra helicopters, and a Crew Chief hence AH-1G. Also flew front seat. (A rush indeed)
I have never seen a flame out, hot starts very seldom.
Gear boxes were not the majority of helicopter accidents.

 

[AH-1G]

Auto rotation can be loss of engine, or loss of hydraulic power. So there are two different ways to perform an emergency landing when these problems occur.
We know the first, hydraulic loss you can still fly, it's like not having power steering. When landing your taught coming in on a very long approach and skid your way to a stop. Not sure how they teach Apache's with hydraulic loss landings?

 

[AH-1G]

@R.Perry,
were you on a SH-3A of type?

 

[clolsonus]

You have a fear of electronics and computers, well don't get on an airliner, most are fly by wire, and the pilots don't fly, the computer does.
Aviation grade electronics has proven very reliable, and most likely any new aircraft will have a redundant system, meaning two flight computers minimum.

This article (written by someone with far better communication skills than I have) does an extremely good job at organizing and communicating thoughts very similar to my own random and scattered thoughts on the state of the art for flight control system development. All the redundancy boiled down to a dependency on single angle of attack sensor that apparently failed, but the MCAS continued to trust it over all the other available information and forced the flight control system to override the pilots. As someone who works in a corner of the industry, my brain explodes over all the red flags that had to have been ignored as they went down the design path .... starting with shocking [in]stability issues with the bare metal airframe.

How the Boeing 737 Max Disaster Looks to a Software Developer

Design shortcuts meant to make a new plane seem like an old, familiar one are to blame

spectrum.ieee.org

In all honesty I would really hesitate to climb on board a boeing 737 max right now and in the next year or two at least. This thread isn't about Boeing, but lets assume Boeing hires the cream of the crop flight control system engineers ... so we might be stuck with the 2nd team for programming the multirotor flight controller ... I don't know. I'm not disagreeing with anything you say, just highlighting places where my skepticism comes from.

So sure, we could pop a chute if the mulitrotor banks beyond some preset limit of 30 or 45 degress ... but it's been very recently demonstrated (twice) that sensing angles in aircraft isn't a perfectly solved problem.

And then things like this happen:

Cirrus Chute Deployment Fails Over Texas, Pilot Still Makes Safe Landing | Aero-News Network

A 2001 SR22, With A REPACKED CAPS Chute, Experiences Rocket Firing But NO Chute Deploy You know you're having a bad day when a flight goes so b| Published: Fri, May 17, 2013 | Aero-News Network

www.aero-news.net

Again, it doesn't mean we won't have multirotors flying us all to work and back in 5 years, it just makes me very skeptical that this can be done safely by humans. And I don't say any of this to discourage anyone from pushing the envelope ... the Wright brothers didn't have everything figured out when they started and they left plenty of things for Glen Curtiss and all the others that stood on their shoulders to figure out.

But I'm still *very* skeptical about scaling up multirotors and using them to fly humans around. Good luck, and I mean that in all sincerity!

Curt.

 

[R.Perry]

@R.Perry,
were you on a SH-3A of type?

No, I was on S2 then P3, I have not flow helicopters, and really don't want to.
You are correct that pilot error is primary reason for aircraft accidents in general. I was talking about mechanical or electrical failures.

 

[clolsonus]

S2 is such a cool airplane.

 

[R.Perry]

This article (written by someone with far better communication skills than I have) does an extremely good job at organizing and communicating thoughts very similar to my own random and scattered thoughts on the state of the art for flight control system development. All the redundancy boiled down to a dependency on single angle of attack sensor that apparently failed, but the MCAS continued to trust it over all the other available information and forced the flight control system to override the pilots. As someone who works in a corner of the industry, my brain explodes over all the red flags that had to have been ignored as they went down the design path .... starting with shocking [in]stability issues with the bare metal airframe.


Curt.

I never implied that there can not be computer glitches, or switch, sensor failures. It is common knowledge that things fail, and always will. However how often do they fail. How many flights are going on world wide everyday without incident. Speak of failures, how about Sue City crash, impeller came apart and severed all three hydraulic lines eliminating all flight controls.
Helicopters only have a decent safety record to to a lot of maintenance, and that is costly.
Why do the airlines insist on their pilots using the flight computer and not fly the aircraft themselves? The reason is obvious, the computer does a more efficient job. It manages course, altitude, speed, environment, basically every aspect of the aircraft except the restroom.

Technology is a great thing, but it isn't perfect, but nothing is. However I'n going to worry about what might happen and miss out of experiencing life.

 

[R.Perry]

S2 is such a cool airplane.

You never flew one, the stuff was a miserable plane to fly, now the P3 was wonderful, and it didn't have a tail hook.

 

[clolsonus]

I got to poke my head in the cockpit of a CDF S2 a few years back when I was working on a flight sim project for them in Sacramento. But for sure I have no idea what it's like to fly them. They sure look cool though.

I just fly RC/UAV stuff (not trying to pass myself off as anything more than that here.) I do that and some software stuff. I have developed a successful flight controller for UAV's from scratch (not an ardu or pixhawk) but the failure scenarios for a 5-10 lb unmanned plane are a lot different than anything you would climb into. We get our triple redundancy by bringing 3 planes to the flying field. (My day job is in a UAV lab at the U of MN as a full time support engineer for the various student and research projects that come though.)

People definitely are working on a variety of manned multi-rotors projects (and also hybrid wing/vtol) so a lot of people think the basic idea is legit enough to sink a lot of time and energy into it. I keep remembering more projects I've seen over the past few years as I type here (some of them getting airborne for real.) Just google evtol and there are tons of prototypes, computer renderings, and ideas out there. But I can't think of anything that's gone to market yet, or anything with a real price on it. Probably Elon Musk will be selling a VTOL Tesla in 2 years that will run off your ipad.

Curt.

 

[Moosewax]

Near future of helos right here;

Coaxial with push prop

 

[PatR]

It ain’t no slouch in the speed department either.

 

[Deltadave]

As for the matter of hazards of clogging the skies and overwhelming ATC, I'm sure the serious have taken this into consideration.
Each aircraft could be connected to each other, and will know where each and every other aircraft are, including conventionals at all time
Pretty sure this would be mandatory, as I'm sure that's how a mass of autonomous cars must be.
Gridlock will go away if each car can do 80 mph, two feet apart from the next.
Nothing is more dangerous than driving on California highways.
I drive by fatal accidents several times a year and think little of it, as it's so common.
Just saw one last night. You can tell when the firetrucks block the scene and people are just kinda standing around.
As for power loss, yes, auto rotation in conventional is nice and I really don't have a legit answer but to equip each with rocket propelled ejection seats out of scuttled Soviet fighters.
At least you get an "E" ticket ride before you die.

 

[AH-1G]

I'm sure some one will try to hack these flights then will see a major disaster.
Autonomous flying and driving is scary.
I watch on YouTube "Corporate Pilot Life", where flying is done mostly by the computer.
Sean been posting videos for several years.
I Enjoy watch, lots of ATC interaction.

 

[AH-1G]