Raptor Aircraft

Racerx said:
Not spray foam. Fuel cell foam. Keeps the fuel from sloshing around as much. Extremely coarse spongy foam you can scrunch up and put through the fuel cap. It in no way will solve anything. Much like his reasoning on the landing gear and putting "L channel"(he means angle) in front of the opening. Rather than him making something to fit the void. Tape would have been a much simpler easier solution.
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well, a couple of pieces of 2024 and some aluminum speed tape would be so difficult to fab.......................................
 
unsafervguy said:
well, a couple of pieces of 2024 and some aluminum speed tape would be so difficult to fab.......................................
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More so than just taping over the well and ending it. Why spend any more time than is absolutely necessary. Does anyone really think his weeble wobble flight was caused by this?
 
Tantalum said:
Yes! The physical world has actual laws. This is my thing with battery tech and development. Tesla has gobbs of money and their battery tech is incremental. I've done the work up on another post somewhere but that top of the line Tesla battery is no where near small enough, light enough, and with enough juice to be theoretically used in something like a Bonanza. Hybrid planes are even dumber since planes operate at sustained high power settings.. "use the gas to get up, electric to cruise, and charge on the way down" doesn't work in reality. Plus, each conversion of energy has losses.. it works in cars due to regenerative breaking and because of the long traffic and idle times.


The whole thing with this airplane that seems the least realistic is the power train. He has enough hurdles to overcome with the plane itself.. using junkyard audi engines is just madness.


That's what I thought he was doing first, putting some vents in the nose cone area with an additional cooler. The only thing 5 gallons of coolant will do is make it take longer to heat up, but also that much longer to cool down. It's probably the dumbest and most illogical solution to the cooling issue he could have possibly come up with.
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The only thing I can say about batteries is that the physics behind them is not fully understood, and there is a possibility there could be a significant breakthrough that would make them considerably more energy dense. I'm not counting on it, but it is a possibility. Even with a major breakthrough, I still don't think it will be enough to make electric airplanes practical.

You're absolutely correct about hybrid technology not being applicable to airplanes. There are two things that hybridization does that is useful in passenger cars, it recaptures energy that would normally be waste heat when braking, and it shuts off the engine at times where power demand is very low and the engine is seeing significant pumping losses. The only time airplanes do any braking are on final approach (propeller drag) and then on rollout. Other than that, from takeoff until final approach, you need energy to keep the airplane aloft and moving forward. Besides, who wants to fly an airplane where the engine stopping is a regular occurrence?

The only thing that I can think of that might be applicable from hybrid cars is what the carmakers are calling Atkinson cycle technology. This uses cam timing to get where the expansion ratio is greater than the effective compression ratio. It's not a genuine Atkinson cycle engine, which used an eccentric setup to physically vary the compression stroke, and is not compatible with modern engine speeds. Instead, it leaves the intake valve open for a part of the compression stroke, so some of the mixture gets pushed back into the intake manifold and gets used by one of the other cylinders. That gives about a 10 percent increase in fuel efficiency, and for auto engines with variable valve timing, this does not come at much of a cost. Of course, in order to get some new technology into the light aviation market, we're going to need a big increase in the number of new airplanes sold. It's unlikely that anyone's going make a new technology engine available as a retrofit for the existing fleet, and the number of new airplanes sold is not enough to justify a major development program. GAMA member companies bought about 1500 new piston engines last year for their total new airplane output. That's less than a day's production at an automobile engine plant.
 
FormerHangie said:
The only time airplanes do any braking are on final approach (propeller drag) and then on rollout. Other than that, from takeoff until final approach, you need energy to keep the airplane aloft and moving forward. Besides, who wants to fly an airplane where the engine stopping is a regular occurrence?
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Good analysis.

There might be a niche for electric planes in the training market where flights are shorter, power requirements a lower and regeneration can start to come into play while going through various maneuvers. Think touch and goes, for instance. I’m guessing even that will take at least 10 years to become practical, but it’s an exciting prospect.
 
The other big issue with hybrid technology is it requires 2x complexity and propulsion systems which add weight (biggest deal for airplane where induced drag is directly related to weight) and takes up room and maintenance issues.

The main reason things that work well in cars don't work well in airplanes is that cars spend most of their time at relatively small percentages of total power and they vary the power lots. Airplanes spend most of their time at high percentages of power and are generally not varied. Much of the gains of efficiency in cars are based on improving the efficiency when varying and a lower power percentage. This is such a large part of a cars normal usage that the gains are significant (even spectacular). In an airplane the are lost in the noise.
 
FormerHangie said:
The only thing I can say about batteries is that the physics behind them is not fully understood, and there is a possibility there could be a significant breakthrough that would make them considerably more energy dense. I'm not counting on it, but it is a possibility. Even with a major breakthrough, I still don't think it will be enough to make electric airplanes practical.
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Surely there will be progress, like we see happening in metallurgy, etc., but those steps are incremental. Even with huge funding behind it, social interest, and lots of government incentives the battery tech improvement are very small. Just looking at pure energy density numbers batteries still have a long way to go before they are true contenders for fossil fuel replacement in all applications. But not impossible.. unlike what Peter thought he could achieve with a 7gph 200ktas+ cruise

FormerHangie said:
The only thing that I can think of that might be applicable from hybrid cars is what the carmakers are calling Atkinson cycle technology. This uses cam timing to get where the expansion ratio is greater than the effective compression ratio. It's not a genuine Atkinson cycle engine, which used an eccentric setup to physically vary the compression stroke, and is not compatible with modern engine speeds. Instead, it leaves the intake valve open for a part of the compression stroke, so some of the mixture gets pushed back into the intake manifold and gets used by one of the other cylinders. That gives about a 10 percent increase in fuel efficiency, and for auto engines with variable valve timing, this does not come at much of a cost. Of course, in order to get some new technology into the light aviation market, we're going to need a big increase in the number of new airplanes sold. It's unlikely that anyone's going make a new technology engine available as a retrofit for the existing fleet, and the number of new airplanes sold is not enough to justify a major development program. GAMA member companies bought about 1500 new piston engines last year for their total new airplane output. That's less than a day's production at an automobile engine plant.
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That's my long standing issue with GA engine tech.. it is SO FREAKING OLD. There are a lot of incremental improvements we COULD see, but we simply don't. Yes yes, the volume numbers are miniscule and if Ford only sold 1,500 cars a year that cost of a car would be astronomical. However internal combustion piston engines do not exist in some separate GA bubble outside of the world. Perhaps the FAA regulations make it so, but there is no real reason one cannot take these small technological advancements and apply them to GA. The cost of many other aircraft components don't totally follow that same "yeah but they only sell 1,500" rule since many of those components exist outside the GA industry. GPSs are relatively cheap (for example), because they also are used in lots of other applications.

Clearly there is demand for better fuel consumption, reliability, etc. That's all Mooney guys talk about it how little gas their planes burn. If Continental put an engine out that burned 30% less gas for the same power output as it's 70 year old counterparts with better reliability, no voodoo leaning science, etc., there would be a home for it in GA. I'm not asking for a breakthrough... but PLEASE, do something!
 
Tantalum said:
That's my long standing issue with GA engine tech.. it is SO FREAKING OLD.
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Think about this for a second. Anyone who builds an experimental airplane can use any engine they want. So what do most of them go with? Airplane engines! The damn things are awfully good at what they do despite being long in the tooth.

Yes, Rotax makes airplane engines. But one of the reasons they can do what they do is they sell a LOT of them for UAVs and other such things. Others have tried, but the long lead time, certification costs and limited manufacturing runs can make it difficult to improve the wheel.
 
Tantalum said:
That's my long standing issue with GA engine tech.. it is SO FREAKING OLD. There are a lot of incremental improvements we COULD see, but we simply don't.

If Continental put an engine out that burned 30% less gas for the same power output as it's 70 year old counterparts with better reliability, no voodoo leaning science, etc., there would be a home for it in GA. I'm not asking for a breakthrough... but PLEASE, do something!
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There have been improvements. We do have some FADEC controlled engines, fuel injection, etc.

The reason for slower development is aircraft engine manufacturers have an entirely different risk profile. Auto manufacturers can experiment with new designs. If there is an issue, they issue a recall (or bury their head in the sand), and worst case scenario is someone ends up on the side of the road with a warranty claim. Their mean failure rate can be much higher without creating a safety issue.

Now if Lycoming or Continental come out with a new engine, the stakes are much, much higher. Even a single failure will create a significant risk of serious or fatal injury. I don't know why anyone would even want to build anything in aviation. You sell a single $40,000 engine, and expose yourself to millions in liability for years to come.
 
midwestpa24 said:
Now if Lycoming or Continental come out with a new engine, the stakes are much, much higher. Even a single failure will create a significant risk of serious or fatal injury. I don't know why anyone would even want to build anything in aviation. You sell a single $40,000 engine, and expose yourself to millions in liability for years to come.
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But at one point, there were new piston GA engines.. it's not like these engines were handed down from God for us to use.. at some point they were new..
 
steingar said:
Think about this for a second. Anyone who builds an experimental airplane can use any engine they want. So what do most of them go with? Airplane engines! The damn things are awfully good at what they do despite being long in the tooth.
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..and if I build a plane some day (I'm looking at you twin Velocity) I'll likely be putting a Continental or Lycoming in it too.. but it still would be nice to have some incremental improvements to these designs
 
Tantalum said:
..and if I build a plane some day (I'm looking at you twin Velocity) I'll likely be putting a Continental or Lycoming in it too.. but it still would be nice to have some incremental improvements to these designs
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Which is funny, since I think if you're going to take a risk on a new engine tech, a twin is the way to go -- and I think the V Twin is one of the few kit twins out there. I suppose you could experiment on an Aircam too. :D
 
There has been experimentation for a long time. While not certain, it is likely true that air cooled boxer engines with the displacement and compression figures produced by Lycoming, Continental, and Rotax are the best possible piston engines for airplanes if your calculus includes the cost of operation, efficiency, and reliability. It is at least as likely that the only realistic room for improvement is a turboprop. And it is almost as likely that, below 400 hp or so, the turboprop is not an actual improvement.
 
Tantalum said:
[snip]
That's my long standing issue with GA engine tech.. it is SO FREAKING OLD. There are a lot of incremental improvements we COULD see, but we simply don't. Yes yes, the volume numbers are miniscule and if Ford only sold 1,500 cars a year that cost of a car would be astronomical. However internal combustion piston engines do not exist in some separate GA bubble outside of the world. Perhaps the FAA regulations make it so, but there is no real reason one cannot take these small technological advancements and apply them to GA. The cost of many other aircraft components don't totally follow that same "yeah but they only sell 1,500" rule since many of those components exist outside the GA industry. GPSs are relatively cheap (for example), because they also are used in lots of other applications.

Clearly there is demand for better fuel consumption, reliability, etc. That's all Mooney guys talk about it how little gas their planes burn. If Continental put an engine out that burned 30% less gas for the same power output as it's 70 year old counterparts with better reliability, no voodoo leaning science, etc., there would be a home for it in GA. I'm not asking for a breakthrough... but PLEASE, do something!
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Could we build airplane engines that were easier to use (FADEC so no "voodoo leaning", push button start, etc.)? Yes. Would we see a 30% increase in efficiency? Nope. The main reason things that work well in cars don't work well in airplanes is that cars spend most of their time at relatively small percentages of total power and they vary the power lots. Airplanes spend most of their time at high percentages of power and are generally not varied. Much of the gains of efficiency in cars are based on improving the efficiency when varying and a lower power percentage. This is such a large part of a cars normal usage that the gains are significant (even spectacular). In an airplane the are lost in the noise.

It turns out that if you operate an engine at one specific RPM for long periods of time, simple mechanical timing for valves, ignition, fuel mixture, etc. can be optimized for that. In cars, the simple mechanical timing and fuel mixtures were always compromises for highly variable operations. Why do high performance muscle cars of the 1960's have the V-8 lope at idle? Because that was what cams, ignition and fuel mixtures set up for wide open operation caused at idle.
 
Datadriver said:
View attachment 91041

Another thing he mentioned in his video was a guess for why the aircraft was bobbing up and down. He mused that it might be the size of his mouseholes in the vertical bulkheads in his fuel tanks. This picture is part of my own velocity build - the "mouseholes" are those half holes you see at the ends of the vertical baffles. In decades of following the velocity community I've never seen a similar issue be related to such holes. PM suggested he might spray foam inside his tanks? I would suggest he fly with full fuel but I know he is pretty heavy as is...
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Full fuel = bigger fire.
 
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jsstevens said:
It turns out that if you operate an engine at one specific RPM for long periods of time, simple mechanical timing for valves, ignition, fuel mixture, etc. can be optimized for that.
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I get that, but I don't believe our 1950s engines are optimized for that as well as they can be. Plus, the atmospheric conditions they operate in and the loads do vary. Cars =/= planes, but it doesn't mean we should just assume that we got 70 years ago is the end all/be all

We already see planes with one electronic ignition (one mag one electric) start and run better and smoother. There is room out there for improvement. Maybe not much economic opportunity, but there's certainly room

Just look at turbines.. every iteration of engine that GE/RR/Pratt release incrementally save fuel.. even though the turbine is already remarkably simple and also just sits at one sitting for thousands of hours.. yet, we don't see airliners flying around with 70 year old turbines
 
Tantalum said:
I get that, but I don't believe our 1950s engines are optimized for that as well as they can be. Plus, the atmospheric conditions they operate in and the loads do vary. Cars =/= planes, but it doesn't mean we should just assume that we got 70 years ago is the end all/be all

We already see planes with one electronic ignition (one mag one electric) start and run better and smoother. There is room out there for improvement. Maybe not much economic opportunity, but there's certainly room

Just look at turbines.. every iteration of engine that GE/RR/Pratt release incrementally save fuel.. even though the turbine is already remarkably simple and also just sits at one sitting for thousands of hours.. yet, we don't see airliners flying around with 70 year old turbines
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And why do you not believe that? Because cars have improved so much? (which they undeniably have.)

Start easier and run smoother is part of the easier to operate. That’s there I grant you. But your desire for 30% efficiency gains is just not there for a properly operated piston engine.

Much of the improved efficiency in turbines has to do with turning them into ducted fans rather than just using the exhaust gas as thrust. (How much came from where you’d have to ask a power plant engineer). And remember how much younger (as a production technology) turbines are. 50+ years younger.
 
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Tantalum said:
Just look at turbines.. every iteration of engine that GE/RR/Pratt release incrementally save fuel.. even though the turbine is already remarkably simple and also just sits at one sitting for thousands of hours.. yet, we don't see airliners flying around with 70 year old turbines
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https://en.wikipedia.org/wiki/Brake-specific_fuel_consumption

Most us have Lycomings and Continentals which operate all day long at ~.45 lb of fuel/hp/hr. That's roughly 12% less efficient than an efficient auto engine. And there are optimized aero engines (current lycomings and continentals) which achieve .40 or below once leaned and in cruise.

Our engines are not misers like you might find in a Prius where they use the battery to hide drivability issues, but they aren't that bad.
 
jsstevens said:
And why do you not believe that? Because cars have improved so much? (which they undeniably have.)

Start easier and run smoother is part of the easier to operate. That’s there I grant you. But your desire for 30% efficiency gains is just not there for a properly operated piston engine.

Much of the improved efficiency in turbines has to do with turning them into ducted fans rather than just using the exhaust gas as thrust. (How much came from where you’d have to ask a power plant engineer). And remember how much younger (as a production technology) turbines are. 50+ years younger.
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Higher compression, smarter injection, tighter tolerances, etc. Maybe not 30% but there are improvements to be had

the core of the turbo fan, the actual jet, has also improved dramatically but part of that is due to better metallurgy allowing for higher temperatures and compression
 
kyleb said:
https://en.wikipedia.org/wiki/Brake-specific_fuel_consumption

Most us have Lycomings and Continentals which operate all day long at ~.45 lb of fuel/hp/hr. That's roughly 12% less efficient than an efficient auto engine. And there are optimized aero engines (current lycomings and continentals) which achieve .40 or below once leaned and in cruise.

Our engines are not misers like you might find in a Prius where they use the battery to hide drivability issues, but they aren't that bad.
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They're not awful.. and for their weight they do their job well. Why I would (will?) still use one in my future v-twin.. but by and large it's still a relative mediocre piece of equipment compared to what we could be getting.. cranked crankcases, magnetos that shred themselves, dubious vacuum pumps that fail, suspect oil leaks here and there, burning oil... we tolerate a lot of nonsense. Our son isn't a drug addict, but he's a solid B student that is not achieving all they can.
 
Tantalum said:
They're not awful.. and for their weight they do their job well. Why I would (will?) still use one in my future v-twin.. but by and large it's still a relative mediocre piece of equipment compared to what we could be getting.. cranked crankcases, magnetos that shred themselves, dubious vacuum pumps that fail, suspect oil leaks here and there, burning oil... we tolerate a lot of nonsense. Our son isn't a drug addict, but he's a solid B student that is not achieving all they can.
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The volume is so low that the economics don't make sense. Let's say that you came up with a clean sheet 180 - 200 hp engine. Chances are to make significant improvements, you'd have something that would not be a drop in replacement for an O-360. How many do you think you could sell in a year, and at what price? How long would it take to recover your investment?
 
Tantalum said:
They're not awful.. and for their weight they do their job well. Why I would (will?) still use one in my future v-twin.. but by and large it's still a relative mediocre piece of equipment compared to what we could be getting.. cranked crankcases, magnetos that shred themselves, dubious vacuum pumps that fail, suspect oil leaks here and there, burning oil... we tolerate a lot of nonsense. Our son isn't a drug addict, but he's a solid B student that is not achieving all they can.
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As far as oil leaks and the like, I look at it like a Harley. They sometimes sit for long periods of time rattle like crazy and have a tendency to leak and burn oil. "You must exercise the gaskets!" Put in glass and you can lose that vacuum pump. But I understand your gripe. The technology out there exists for most all GA aircraft to have some sort of diesel replacement. It's just not economically realistic even if there were any stc. The experimental market and Europe is where things are SLOWLY advancing.
 
Tantalum said:
Higher compression, smarter injection, tighter tolerances, etc. Maybe not 30% but there are improvements to be had

the core of the turbo fan, the actual jet, has also improved dramatically but part of that is due to better metallurgy allowing for higher temperatures and compression
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How (in the specific case of a low RPM, constant speed engine) would higher compression help? How would "smarter fuel injection" help?

And remember, we're talking specifically about fuel efficiency here. That we could build more reliable and certainly easier to use engines and accessories I have not argued.

John
 
Perfect storm of the requirements of an airplane engine are quite different from the needs of an auto engine, the low volume of engines/less of a business opportunity to recover and make profit on engine development and tooling, and a huge legal bullseye on aircraft engine makers.
 
To bring the thread back toward its topic, here's another YouTube gem. "I believe it's going to be the Tesla of the air, and since I already have a Tesla..." Financial advice and airplane buying advice, both from a non-pilot who thinks that it is "really ironic" that he paid his Raptor deposit before he wrote his book. I can't watch beyond that but maybe someone here will and you can share with us the secret of how to buy a Raptor Aircraft with life insurance.

 
Kenny Phillips said:
Fuel fuel = bigger fire.
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I take your comment in jest:), but note that some test pilots (wasabi for example) state they like first flights to be full fuel. I'm not sure if Raptor can fly full now due to weight concerns:eek:
 
Datadriver said:
I take your comment in jest:), but note that some test pilots (wasabi for example) state they like first flights to be full fuel. I'm not sure if Raptor can fly full now due to weight concerns:eek:
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I can say with absolute certainty that my fuel planning has never taken into consideration the size of the fire that might result. o_O:D

Nauga,
who says, "FOOM"
 
Brad Smith said:

The perfect “Raptor” customer. No knowledge whatsoever about aircraft but lots of money in their pocket. There’s one born every minute.
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You've got to take a look at this guy. He's hilarious! He looks to be 20 or 22 years old and he put's himself out as a financial expert consultant/podcast guru. He invests in life insurance. Whole life. No, I'm not making that up.

Never pay cash. Pack a ton of money into whole life and then borrow against it. That's how you can buy airplanes.

He spins a lot of numbers in an excel sheet and combines it with the wisdom of a 22 year old, and speaks with great conviction.

Lots of numbers, no experience, a multitude of false assumptions. He's making lots of money now not from his "system" but by selling books.
 
WDD said:
He's making lots of money now not from his "system" but by selling books.
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That's what most of these losers do.. so many people also pour tons of money into a worthless investment courses.. think about it, all you need to do is sell a $2,500 product to 500 people and you are a millionaire!
 
jsstevens said:
How (in the specific case of a low RPM, constant speed engine) would higher compression help? How would "smarter fuel injection" help?
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My last note on this, and then we can start a new thread or dig up one of the countless others

Just look at the marine outboard industry.. even 2-strokes. What you can buy today brand new from Honda or Evinrude or any of those guys is not at all comparable to what they were selling in the 1950s

The marine environment is harsh, and at least in the case of outboards also necessitates relative lightweight and dependability so that poor guy out fishing 20 mi from shore in his center console can still get home. Mind you, these engines will go hundreds of hours at 4,000 RPM..

Financials aside, we have not reached the apex of what ga piston can technically, physically achieve
 
Tantalum said:
That's what most of these losers do.. so many people also pour tons of money into a worthless investment courses.. think about it, all you need to do is sell a $2,500 product to 500 people and you are a millionaire!
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Like most of these financial "gurus"...They don't make a living off of how they invest. They make a living off of seminars and books. Think about it, if you had a trick to make all this money, why on earth would you tell anyone your financial secret. Same thing as the house flip seminar.
 
Tantalum said:
Just look at the marine outboard industry.. even 2-strokes. What you can buy today brand new from Honda or Evinrude or any of those guys is not at all comparable to what they were selling in the 1950s
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Well, no longer Evinrude; that brand was dissolved earlier this year
 
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