Technology Today vs the 1960 Mooney Design

[toto]

I always thought Rutan's asymmetric Boomerang was a clever solution to the critical engine problem. 

http://rutanboomerang.com/

It also just looks way cooler than a 337

[carusoam]

@KLRDMD let’s invite the good doctor to discuss the C337...

He may have some first hand knowledge of it.

Best regards,

-a-

[toto]

2 hours ago, aviatoreb said:

The rotax are generally very popular with small experimental and sport airplanes.  Why don't we see them on certified?

A friend has a lot of time in a Tecnam twin Rotax, and raves about it. I believe the Tecnam has an FAA type certificate, but I think they've also moved on from Rotax to Lycoming. Not sure if they're still making Rotax-powered twins today. 

[aviatoreb]

48 minutes ago, toto said:

I always thought Rutan's asymmetric Boomerang was a clever solution to the critical engine problem. 

http://rutanboomerang.com/

It also just looks way cooler than a 337

Wow- that is UGLY!  

I Love it!

[aviatoreb]

1 hour ago, toto said:

I always thought Rutan's asymmetric Boomerang was a clever solution to the critical engine problem. 

http://rutanboomerang.com/

It also just looks way cooler than a 337

Wow - I had never heard of the boomerang...but now I have - thanks!

Performance looks phenomenal - 264kts cruise at 75% and 1500nm range, or 2100nm at 210kts at 50%.  WOW!  And twin tsio360 burn so must be 22gph total at 75%?  only downside is a very very high stall speed.  88kts at cruise.  I hope it comes with a space shuttle parachute.

I never heard of it - but matchbox has: https://www.amazon.com/Matchbox-Busters-Rutan-Boomerang-White/dp/B083HNRGSC

[carusoam]

Once you have seen the boomerang....

You are going to want a tri-motor....   

-a-

[KLRDMD]

1 hour ago, carusoam said:

@KLRDMD let’s invite the good doctor to discuss the C337...

He may have some first hand knowledge of it.

I have no data on the normally aspirated or straight turbo models but I own my second P337 now. It is a great airplane for what it is, as most airplanes are.

[cliffy]

Anyone remember the Adam 500?

[carusoam]

Partial memory...

Seems like unfinished business...

Another example of a heavy composite plane... that never got to the Bravo model...

https://en.wikipedia.org/wiki/Adam_A500

-a-

[EricJ]

38 minutes ago, cliffy said:

Anyone remember the Adam 500?

There was one at the Pima Air Museum the last time I was there.

[Planegary]

Years ago I ran into the test pilots flying the Adam aircraft. They were inside trying to warm up since a heater had not been installed.I wanted to stop and visit with them for a few minutes but life intervened and my pax showed up and I had to head out without speaking to them

[aviatoreb]

Aren’t “they” testing an electric 337 in Hawaii on a commercial route right now?

[Blue on Top]

2 hours ago, aviatoreb said:

Aren’t “they” testing an electric 337 in Hawaii on a commercial route right now?

Yes!  And they are doing the right things!  They have replaced one of the engines with an electric motor and calling it "hybrid".  That is kind of misleading as both propulsion devices are not outputting the same power.  (note: I can't believe that I am going to say this ... especially to Erik of all people) But do the math.  Very good Lithium-ion battery energy density is slightly above 150Wh/kg.  For both propulsive devices to be outputting the same power all the time, the gross weight would be so high that the airplane couldn't get airborne.

Check out Pearl Harbor Aviation Museum.  They did an hour-long webinar on 1/29/21 on this vehicle.  Wonderful presentation. Yes, they flew from LA to SF with this hybrid ... again, do the math for how much the electric motor was contributing ... and when.  PHAM also did a webinar this past Friday (2/12) on a hydrogen fuel cell (ignore the costs) airplane.  Both are cool webinars to watch ... with the reality filters on.

So, why do I say they are doing the right things?  They are getting all the other bugs worked out before (if and when) the solution to the energy density equation comes along.  Because of centerline thrust, they don't have to deal with assymetric thrust when a propulsive device quits (distribution is much, much easier).  They are dealing with motor cooling (Cessna already did the engine cooling portion).  Motor power is NOT the issue.  Even at 90-95% efficiency, cooling is.

More than my 2 cents, but this excites me. =Ron

[aviatoreb]

48 minutes ago, Blue on Top said:

Yes!  And they are doing the right things!  They have replaced one of the engines with an electric motor and calling it "hybrid".  That is kind of misleading as both propulsion devices are not outputting the same power.  (note: I can't believe that I am going to say this ... especially to Erik of all people) But do the math.  Very good Lithium-ion battery energy density is slightly above 150Wh/kg.  For both propulsive devices to be outputting the same power all the time, the gross weight would be so high that the airplane couldn't get airborne.

Check out Pearl Harbor Aviation Museum.  They did an hour-long webinar on 1/29/21 on this vehicle.  Wonderful presentation. Yes, they flew from LA to SF with this hybrid ... again, do the math for how much the electric motor was contributing ... and when.  PHAM also did a webinar this past Friday (2/12) on a hydrogen fuel cell (ignore the costs) airplane.  Both are cool webinars to watch ... with the reality filters on.

So, why do I say they are doing the right things?  They are getting all the other bugs worked out before (if and when) the solution to the energy density equation comes along.  Because of centerline thrust, they don't have to deal with assymetric thrust when a propulsive device quits (distribution is much, much easier).  They are dealing with motor cooling (Cessna already did the engine cooling portion).  Motor power is NOT the issue.  Even at 90-95% efficiency, cooling is.

More than my 2 cents, but this excites me. =Ron

It does seem like a fantastic concept.  I love also when something critical - like power - has two entirely different systems for the ultimate in redundancy.  Vs say a standard twin engine where still a common loss of power is fuel problems.

Center thrust is cool.

But I cannot do the math - since I don't know any of the constants.  That's...engineering.  :-O

[Blue on Top]

11 minutes ago, aviatoreb said:

It does seem like a fantastic concept.  I love also when something critical - like power - has two entirely different systems for the ultimate in redundancy.  Vs say a standard twin engine where still a common loss of power is fuel problems.

since I don't know any of the constants.  That's...engineering.  :-O

So very rough numbers (so I can do the math ), The engines on a 337 are 160kW each.  We'll say it's a very good Lithium-ion battery at 160 Wh/kg.  Each hour of flight for each motor requires 1000 kg (2,200 lbs.) of batteries.   This assumes that the batteries can be used to 100% capacity (65-70% is more realistic).  In the end, a flight of 4 hours on a C337 will require 17,600 lbs. of batteries ... at 100% capacity.  Not practical ... yet.  Fuel cells need to get less expensive.

[cliffy]

Just to speculate- (as I said many many years ago)

If we had good CHEAP fuel cells (of such output as for this airplane) each home could have its own fuel cell for power. each commercial building could have its own fuel cell. 

Think where that could put us  overall in the power generation market on a worldwide stage?

How about national security where by our power grid would no longer be vulnerable to attack? Kill our grid and we have anarchy in 72 hrs. (check out recent news speculations)

I know CHEAP is a relative term but it could happen.

With a good fuel cell THEN we have a new paradigm for aviation.

Until then we will be consigned to the land of dinosaurs both figuratively and realistically - even with better batteries!  

Batteries are just a stop gap in the paradigm shift in power generation.

[aviatoreb]

9 hours ago, Blue on Top said:

So very rough numbers (so I can do the math ), The engines on a 337 are 160kW each.  We'll say it's a very good Lithium-ion battery at 160 Wh/kg.  Each hour of flight for each motor requires 1000 kg (2,200 lbs.) of batteries.   This assumes that the batteries can be used to 100% capacity (65-70% is more realistic).  In the end, a flight of 4 hours on a C337 will require 17,600 lbs. of batteries ... at 100% capacity.  Not practical ... yet.  Fuel cells need to get less expensive.

I wonder if we really need both of the props spinning on a 337.  I see three reasons for two engines. 1) greater useful load to lift more stuff, 2) redundancy of having a second engine for back up especially during take off, and also in cruise just in case, 3) speed.

3 seems like the weakest reason since two engine airplanes are not much if any faster.

So how about a 337 where the second engine is electric but is only used for maybe a half hour total during a flight for take off, and then shut down for cruise but at the ready and stand by in case there is an emergency.  So then you would not typically as much battery reserve.  60 min worth?

[N201MKTurbo]

9 hours ago, Blue on Top said:

  Fuel cells need to get less expensive.

Haven't they been saying that for the last 60 years, yet no cheap or robust fuel cells. 

That would be the holy grail wouldn't it. A Carnot engine can only extract 30% of the energy from fuel, a fuel cell can extract almost 100% of the energy. Couple that with an electric motor that is 95+% efficient and you have a great propulsion system.

They have made fuel cells that work with hydrocarbons, but they emit CO2 also. Can't get away from that.

[Igor_U]

On 2/12/2021 at 8:56 PM, cliffy said:

Anyone remember the Adam 500?

Sure do.

Picture taken last fall at KBVS:

 

[MikeOH]

10 hours ago, aviatoreb said:

So how about a 337 where the second engine is electric but is only used for maybe a half hour total during a flight for take off, and then shut down for cruise but at the ready and stand by in case there is an emergency.  So then you would not typically as much battery reserve.  60 min worth?

Ah, so only 2200 pounds of batteries!

[MikeOH]

Whether it's fuel cells or batteries...the 'breakthrough' is 'just around the corner.'. Sorry, what all the fan-boys call my cynicism, I call reality after hearing this for the last 50 years!  Batteries just don't have the energy density, not even close.

Fuel cells are great, despite their cost, but everyone seems to ignore where the energy comes from.  You're going to have to spend money for 'energy' somewhere to create the 'fuels' that go into the fuel cell...either by 'mining' hydrocarbons (like natural gas), or using massive amounts of other energy sources to create, for example, hydrogen and oxygen.  Not to mention safely storing those gases on board a high-speed aircraft.

[N201MKTurbo]

Ok, I have to tell a hear say story about fuel cells.

I guy I used work with at the medical company, used to consult with NASA. They were having an electric car competition here in AZ back in the early 80s. He entered, but convinced NASA to loan him an Apallo fuel cell. He built a car with a 400 HP electric motor. He had all these hydrogen and oxygen cylinders in the back. All the other cars were racing along at like 40 MPH and getting like 20 laps at PIR. He was going like 150 MPH and going all day long. He said after the first day he was disqualified fo not being in the spirit of the competition.

[MikeOH]

Just now, N201MKTurbo said:

Ok, I have to tell a hear say story about fuel cells.

I guy I used work with at the medical company, used to consult with NASA. They were having an electric car competition here in AZ back in the early 80s. He entered, but convinced NASA to loan him an Apallo fuel cell. He built a car with a 400 HP electric motor. He had all these hydrogen and oxygen cylinders in the back. All the other cars were racing along at like 40 MPH and getting like 20 laps at PIR. He was going like 150 MPH and going all day long. He said after the first day he was disqualified fo not being in the spirit of the competition.

Great story!  Gotta hate the result.  Reminds me of what happened to my son many years ago in a paper airplane contest.  His flew farther (the criteria for winning) but was disqualified because his was a hoop design and  "didn't look like an airplane"....I was majorly pi$$ed off, but, to his credit, didn't want dad to make a scene with his teacher.  So, I let it go...but, it still rankles me!

[cliffy]

24 minutes ago, N201MKTurbo said:

Ok, I have to tell a hear say story about fuel cells.

I guy I used work with at the medical company, used to consult with NASA. They were having an electric car competition here in AZ back in the early 80s. He entered, but convinced NASA to loan him an Apallo fuel cell. He built a car with a 400 HP electric motor. He had all these hydrogen and oxygen cylinders in the back. All the other cars were racing along at like 40 MPH and getting like 20 laps at PIR. He was going like 150 MPH and going all day long. He said after the first day he was disqualified fo not being in the spirit of the competition.

sounds like the STP Turbine race car at Indy. Clobber the field and then disqualify it for future racing. A 50 cent part broke and kept it from winning. 

[aviatoreb]

1 hour ago, MikeOH said:

Whether it's fuel cells or batteries...the 'breakthrough' is 'just around the corner.'. Sorry, what all the fan-boys call my cynicism, I call reality after hearing this for the last 50 years!  Batteries just don't have the energy density, not even close.

Fuel cells are great, despite their cost, but everyone seems to ignore where the energy comes from.  You're going to have to spend money for 'energy' somewhere to create the 'fuels' that go into the fuel cell...either by 'mining' hydrocarbons (like natural gas), or using massive amounts of other energy sources to create, for example, hydrogen and oxygen.  Not to mention safely storing those gases on board a high-speed aircraft.

Yes - I am a fan boy.

I will be shocked if we are flying "gasoline" powered airplanes in 50 years.  Something else is coming.  What will it be?  No one can say for sure.  I find it very credible that electric will continue to improve - dramatically.

If someone told 1850-man that we would make small metallic devices where small explosions would drive a piston up and down - and generate 1000hp and more, just 100 years later.  Or showed the wright brothers a WWII massive radial engine, or a turbine engine of just a few years after that give all they had was a tiny home made engine.

Something is coming.

What are we to do.  Not work on it and not improve every and all reasonable tech until then? Or just wait wait wait until one day, magically, the right tech suddenly comes ready to go, fully formed?  whatever it might be.

Thousands and thousands of engineers and scientists, trying every and all combination of many different directions of possibilities, in search of the next great thing, has been exactly what has given us always the next great thing, and why our tech is so fantastic today and keeps getting better and better.  

It is the infinite number of monkeys approach.  https://en.wikipedia.org/wiki/Infinite_monkey_theorem

I am just one such monkey.