Raptor Aircraft

Tantalum said:
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
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Which still doesn't answer my specific question about why you think there's more efficiency to be found here. And yses, this should probably be picked up on one of the other threads...
 
atbroome said:
Well, no longer Evinrude; that brand was dissolved earlier this year
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Johnson and Evinrude merged in the 1960s? somewhere around there. Same engines, different branding...
 
Tantalum said:
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
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How many outboards were sold last year?

How many aircraft engines?

There you go.
 
jsstevens said:
Which still doesn't answer my specific question about why you think there's more efficiency to be found here.
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to flip it around, why do you think there *aren't* any further efficiency gains to be found in our engines? Surely advances have been made since 1950 that can be applied to our engines?

donjohnston said:
How many outboards were sold last year?

How many aircraft engines?

There you go.
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which is why I said "finances aside" as a response to the notion that we've reached peak performance of GA engine tech some 70 years ago

But I digress.. easier to just say "yeah, you guys are right. That Continental that might crack its crankcase 900 hours in or the magneto that may shred itself 250 hours after overhaul.. or that weird suspect low compression cylinder, hard starting, sometimes running rough at this weird RPM, why is my one cylinder always 50* hotter than the others?" or really any of the ailments that so often get asked on forums is the best we can get. No sense asking for more, or desiring more. We accept mediocrity everywhere else in life, why not also accept it from the single most important piece of equipment keeping us alive

And it's a straw man to say "yeah but car engines..." - however, they do serve as an analog since both are, after all, ICE. Garmin doesn't exist just to supply the single engine GA fleet, however, the single engine GA fleet gets to enjoy Garmin's advances from marine, etc.

Back to Peter's tom foolery.
 
atbroome said:
Well, no longer Evinrude; that brand was dissolved earlier this year
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I hadn't seen that one. They finally managed to kill of Johnson and Evinrude. I don't think Evinrude ever recovered from the Ficht-direct injection engine failures from the late-90's. It turned a ton of people off from Evinrude, and by the time they had rectified the issue everyone had gone to Mercury/Yamaha/Honda by that point. Sad to see Evinrude die off though, I think it had been operating for over 100-years.

Unrelated to topic, but I used to love the mid-80's 90HP v4 Johnson that was on my grandfather's bass boat. It was sometimes a bit cold-natured and didn't want to start easily when it had sat for a month or two, but once it fired up that thing was good to go the rest of the weekend. Created quite the 2-stroke smoke show on that first cold start, ran clean after that. Dependable as could be.
 
Regarding the wobble.. there are actually a few smart comments in YT on this one. Notably, the wobbling may be caused by incorrect incidence on the winglets, assuming they're also lifting bodies.. this would exacerbate a wobble by loading and unloading them. I imagine they AREN'T lifting bodies.. but who knows, Peter may have just taken the general wing shape and "bent it up" in his design
 
FastEddieB said:
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.
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I think there's one other niche. Small eVTOL aircraft take a lot of crap from the aviation community because so many of the companies pushing that tech understand so little about the current state of general aviation, but there are legitimate aircraft out there proving urban air mobility could become a thing. Kittyhawk's Heaviside has a lower specific consumption (electricity, not gas) than a Tesla Model S and has demonstrated a range of >100 sm in an unmanned configuration. Manned would be lower, but probably still enough to use as a George Jetson lookalike commuter, and this is still an early prototype in the grand scheme of things. I think we are decades rather than years away from that shift, but I do think it'll happen.
 
Tantalum said:
to flip it around, why do you think there *aren't* any further efficiency gains to be found in our engines? Surely advances have been made since 1950 that can be applied to our engines?
[snip]
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Because engines that are run at set constant speeds are easy to optimize with 1950's mechanical valve, ignition and fuel timing and metering. Which I have said over and over...

Reliability? Better cooling (which we have made advances on, see things like the LoPresti cowls. And yes, I know they're touted as lower drag, which they are.)? Easier operation? Sure. ALl that's possible but apparently not finically attractive enough to warrant the expense.
 
Tantalum said:
to flip it around, why do you think there *aren't* any further efficiency gains to be found in our engines? Surely advances have been made since 1950 that can be applied to our engines?
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Thermodynamics. She is a pretty mean B%^&) and hard to cheat on.

Thats why large bore air cooled engines running<3000rpm wont get much more efficient than they are.
 
Another view of what an aircraft engine needs, and why improvements aren’t that easy.

Aircraft engines benefit from high torque, low rpm speeds, meaning long strokes and bigger displacement. With that design there isn’t much to gain by going away from its clunky push rods, etc.

Rotax is great with higher rpm over square and lower displacement per HP engines - works ok for smaller hp/ output (100 HP) I don’t think that works for a durable 200 HP+ engine though.
 
ChemGuy said:
Thermodynamics. She is a pretty mean B%^&) and hard to cheat on.

Thats why large bore air cooled engines running<3000rpm wont get much more efficient than they are.
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What he said

torque X RPM = HP. To get lighter weight run a smaller displacement engine at higher RPM.

Higher RPM usually means less reliability.
 
WDD said:
I don’t think that works for a durable 200 HP+ engine though
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It works for boats..? That's why I brought up marine outboards.. a relatively small object screams out 350 hp for hundreds of hours at high rpm in an unforgiving environment.. and every year emissions on these things get better. They basically operate similarly to aircraft engines in that they sit at one power setting for most of their life

ChemGuy said:
Thermodynamics. She is a pretty mean B%^&) and hard to cheat on.
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I generally hate the argument "I just don't believe that" - but here I have to invoke it lol, I just don't believe that what was built and designed in the 1940-50s and is hand assembled out of sandcast molds with so much variability between engine to engine that we've reached peak performance. Maybe there is no money in improvement, but I bet you could squeeze a smarter piston power plant into a plane if you really tried. Maybe no one has tried because gains are limited and there's no financial prospect for it but it doesn't mean it's not possible

Let's see how the Otto people do.. they are also using a novel piston design. Granted it is diesel, but they have some lofty goals they're trying to hit. We'll see how close they can get
 
High rpm screaming is less reliable than a bigger loping lower rev engine, all things equal. Less things moving per unit of time per hp. Which is why over the road trucks have very large engines with surprisingly low peak HP. They run forever

Yes a higher revving reliable engine can be done. It just costs more.
 
Theres several reasons we haven't seen the innovation in the GA engines. I think they all tie into one another. Most of our planes had designs in the 50's. Since about the mid 70s it's been a rather niche market. Part of that is because the planes made in the 60s are here today. They're not like cars or boats where they get worn out from their environment. More like motorcycles. Kept indoors, enjoyed sparsely. Coincidentally both markets are struggling. Now the one thing motorcycles have is the ability to do whatever it is you want to them. You can't do that with a Cherokee. FAA says nay nay. Is their a market for "something better"? Absolutely. But how do you go about that and how does it become profitable? After all without profit there's no incentive towards innovation. The diesel market is there. But the cost to retrofit a 172 with the CD-155 is 78,000 bucks...and thats without labor. No incentive to do that in the States. If someone were to make something that's more bulletproof the FAA approval and stc makes the cost astronomical.

The tech exists. That's not the argument. But with a huge majority of general aviation being forcibly stuck with things from the 50s-70s the market to innovate wasn't and really isn't there. At least in the states. Overseas where fuel is an issue is a different story. That's why we see a new cirrus with the same design from way back. No other options exist for the cirrus because no other options exist for anyone else.
 
Tantalum said:
but who knows, Peter may have just taken the general wing shape and "bent it up" in his design
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That's exactly how the winglets on a Velocity are. Pretty sure they're like that on Long-EZ's and Cozy's as well.

My vote is that part of his problem is the location of the main gear wells.
 
donjohnston said:
That's exactly how the winglets on a Velocity are. Pretty sure they're like that on Long-EZ's and Cozy's as well.
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Thanks! so do you think there's a merit to the wobble being caused by wrong winglet incidence?
 
unsafervguy said:
Yes and give you seen the price of an outboard lately? a Yamaha 150hp 4 cyl 4stroke is 17k
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Boaters, like pilots, are rich. West Marine charges quite a severe premium on most of what they sell
 
WDD said:
I blame gov regulations. Mainly because I want to toss this grenade and see how hard of a turn this thread can go.
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I get it that you are making a joke here, but I dare say it is more costly for a carmaker to certify a new drive train than for an aircraft manufacturer to certify a fixed gear four seater.
 
Did one already fall off 26 seconds in?
 
Racerx said:
Theres several reasons we haven't seen the innovation in the GA engines. I think they all tie into one another. Most of our planes had designs in the 50's. Since about the mid 70s it's been a rather niche market. Part of that is because the planes made in the 60s are here today. They're not like cars or boats where they get worn out from their environment. More like motorcycles. Kept indoors, enjoyed sparsely. Coincidentally both markets are struggling. Now the one thing motorcycles have is the ability to do whatever it is you want to them. You can't do that with a Cherokee. FAA says nay nay. Is their a market for "something better"? Absolutely. But how do you go about that and how does it become profitable? After all without profit there's no incentive towards innovation. The diesel market is there. But the cost to retrofit a 172 with the CD-155 is 78,000 bucks...and thats without labor. No incentive to do that in the States. If someone were to make something that's more bulletproof the FAA approval and stc makes the cost astronomical.

The tech exists. That's not the argument. But with a huge majority of general aviation being forcibly stuck with things from the 50s-70s the market to innovate wasn't and really isn't there. At least in the states. Overseas where fuel is an issue is a different story. That's why we see a new cirrus with the same design from way back. No other options exist for the cirrus because no other options exist for anyone else.
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You left off the single biggest obstacle - liability insurance. Small scale/ big risk.
 
Mercury is now selling 450 HP outboards with a three year warranty. They are supercharged 4.6L V-8s and cost around $58K. Based on reports from owners, they are very reliable.

Just a random data point.
 
One drawback to a pusher is that the air reaching the prop is partially blocked and/or disturbed by the fuselage or nacelle. It seems like adding that lip to the scoop in the back would divert even more air away from the prop, decreasing its efficiency, if only a little. Regardless, I don’t see how he expects that to enhance the cooling airflow.
 
FastEddieB said:
One drawback to a pusher is that the air reaching the prop is partially blocked and/or disturbed by the fuselage or nacelle. It seems like adding that lip to the scoop in the back would divert even more air away from the prop, decreasing its efficiency, if only a little. Regardless, I don’t see how he expects that to enhance the cooling airflow.
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Peter needs to find an aviation buddy he trusts. And he needs to use that person as a sounding board. Based on what I'm seeing, he's making all of this up as he goes and installing the first fix he comes up with, regardless of how nonsensical the fix really is.
 
3393RP said:
Mercury is now selling 450 HP outboards with a three year warranty. They are supercharged 4.6L V-8s and cost around $58K. Based on reports from owners, they are very reliable.

Just a random data point.
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Yup, and seeing those 450Rs mounted 4 or 5-across the back of some offshore power boats is an insane amount of money compared to just using a pair of Merc Racing 1050 inboards, but I digress. I'm sure with the surface drives and other supporting hardware it's all a wash in the end when you've got $800K+ sunk into a 38' boat.
 
Does tufting right up against the prop give you any information except yep...prop works! Cover the whole damn plane not such small areas. You know at least some air is getting where it needs but you don't know if there's turbulence 12" from the scoop
 
Was just reading the comments from this vid. Their was an Audi engineer that previously suggested removing one turbo and someone asked why. Someone else replied that Peter had stated it's a lot of work and he didn't think it would solve anything. Yep, peter knows better than the guy that had a part in engineering the damn thing. Another person pointed out his tail number 2TD...2Turbo Diesel. Yes I believe Peter is that much of a stubborn fool.
 
SoonerAviator said:
Yup, and seeing those 450Rs mounted 4 or 5-across the back of some offshore power boats is an insane amount of money compared to just using a pair of Merc Racing 1050 inboards, but I digress. I'm sure with the surface drives and other supporting hardware it's all a wash in the end when you've got $800K+ sunk into a 38' boat.
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Indeed, the current hot setup is four or even five 450s hung on a center console hull anywhere from 40' to 65' in length. Builders like MTI, NorTech, and Cigarette, that are best known for their performance based offshore racing hulls, have jumped into the lucrative market.

By the way, the latest stern drive offering from Mercury is the Mercury Racing QC-4v engine. Instead of using a modified GM block like all previous Mercury Racing engines, the QC-4v is a clean sheet design from their in house engineering division.

It's a 9.0L/552 CI V-8, with a four valve DOHC head and dual turbochargers. There are four different horsepower ratings available: 1350, 1550, 1650, and 1750. It is matched to a M8 dry sump transmission and drive. The 1750 list price is just over $225K.
 
A 200hp Lycoming weighs 330 pounds. A 200 HP outboard weighs 500. They also enjoy the luxury of an unlimited supply of cold water for cooling, and through thermostats, get to operate at a constant temp, reguardless of load or rpm. Something an air cooled motor can't enjoy so you can't get the benefit of tight tolerances and precisely controlled fuel/air ratios. The environment they operate (Cylinder head temps, oil temps, air inlet temps, etc) in is very controlled and varys little. Now look at an aircraft engine, Air inlet temps go from 100 deg to the negative numbers routinely every flight. Oil temp vary with load on every climb and decent. Same for CHT and EGT. So, if you want the modern advancments of a marine engine in an aircraft, you need to make it water cooled, have a large enough cooling sysem and water load to cover all situations, and constantly varying thremostats and poppet valves to maintain temps, and never fly where air temp is going to vary much, like what your typical outboard sees its whole life.

Tantalum said:
It works for boats..? That's why I brought up marine outboards.. a relatively small object screams out 350 hp for hundreds of hours at high rpm in an unforgiving environment.. and every year emissions on these things get better. They basically operate similarly to aircraft engines in that they sit at one power setting for most of their life
Click to expand...
 
Air temp is of little concern when the other things you mention are within narrower ranges.
 
Racerx said:
Does tufting right up against the prop give you any information except yep...prop works! Cover the whole damn plane not such small areas. You know at least some air is getting where it needs but you don't know if there's turbulence 12" from the scoop
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Tufts 24” long also seem a little unorthodox.
 
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