Raptor Aircraft

EdFred said:
So there are zero losses when converting from mechanical/chemical energy to electrical, to convert back to mechanical? This is good to know. I'll retro fit all my vehicles to put an electric motor off the crank shaft to run the transmission or prop. Should work out better.
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You appear to have reinvented the hybrid car, but worse.
 
So from an RC perspective, a tiny version of this would fly, powered by brushless motors and a lipo battery. But while in theory, ducted fans can be more efficient than props, I've never seen that happen in RC. Scaling it up to full size, to get 30HP out of each fan unit, he's going to have to put more than 22k watts into it. Or in other words, to effect the same INPUT power to the fan units, he would need the equivalent of 44 1 Kilowatt Honda generators. Electric motors small enough to fit into a 24" ducted fan exist, but they're water cooled. All to get the same input energy as a Piper Cub, with an aircraft that is supposed to weight about twice as much. Let's not forget that a Cub has about a 6' prop, or about 4.5 times the area of the ducted fans. This is just a silly design.

The USS Slater, docked in Albany, uses diesel electric drive, as do most modern trains. One of the advantages of electric drive is that an electric motor can be efficiently driven over a very wide range of speeds. In addition, power can be easily divided between multiple motors, and an electric motor is more resistant to momentary changes in load than an internal combustion engine. None of these advantage are helpful in an aircraft, though.

I have to believe that someone is just making drawings to test how gullible people are. Or maybe it's the theory that the goofier the idea, the easier it is to get investors to throw money at it?
 
Albany Tom said:
So from an RC perspective, a tiny version of this would fly, powered by brushless motors and a lipo battery. But while in theory, ducted fans can be more efficient than props, I've never seen that happen in RC. Scaling it up to full size, to get 30HP out of each fan unit, he's going to have to put more than 22k watts into it. Or in other words, to effect the same INPUT power to the fan units, he would need the equivalent of 44 1 Kilowatt Honda generators. Electric motors small enough to fit into a 24" ducted fan exist, but they're water cooled. All to get the same input energy as a Piper Cub, with an aircraft that is supposed to weight about twice as much. Let's not forget that a Cub has about a 6' prop, or about 4.5 times the area of the ducted fans. This is just a silly design.
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Thank you for doing some rough “back of the envelope” calculations. They seem to reinforce what, just at first glance, seem like obvious flaws in the concept.

That said, the post is really more appropriate to the new Raptor NG thread.
 
Ah... Sorry about that. My mistake. Looked at 'watched threads' before I noticed the thread for the new design.
 
FastEddieB said:
I think it’s closer to a Ponzi Scheme. I don’t think the two are quite synonymous.
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A pyramid scheme is very similar to a chain letter. People buy into the pyramid, and if and when a certain number of other people also buy into the pyramid scheme, then those who bought in earlier get paid. A Ponzi scheme is where an organizer, such as Bernie Madoff, offers an investment, and pays off the early investors with funds received from later investors, until the whole thing collapses. What Peter's doing is neither of these, he's gathering venture capital and is going to fail at creating a viable product. What he's doing is not illegal, unless he is making misrepresentations as to what he's doing. If he tells the investors up front that there is a strong possibility that the venture will fail, then he's pretty well covered himself. As long as he doesn't do anything outlandish with the money, he's not going to be charged with a crime.
 
I guess if your definition of interesting is “pointless wastes of energy and resources to prove well-known principles” then sure, I’ll happily concede to missing that point.
Next, do a mountain propelled by solid rocket boosters.
 
FormerHangie said:
What Peter's doing is neither of these, he's gathering venture capital and is going to fail at creating a viable product.
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Sounds like “Springtime for Hitler”, from “The Producers”!

Well, I guess everybody needs a hobby!
 
FastEddieB said:
Sounds like “Springtime for Hitler”, from “The Producers”!

Well, I guess everybody needs a hobby!
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I thought of that movie when I was responding to you last night. I suppose it's easier to sucker some investors into bankrolling a pie-in-the-sky-project than it is to actually create a product that would succeed in the marketplace.
 
DaleB said:
And correct me if I'm wrong, but won't this thing require a type rating, since it's now a multiengine jet? I suppose it's up for debate whether a ducted fan is a "turbofan" according to the FAA or not, since I don't think anyone has ever flown one, but I somehow suspect they'll say it is.
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It does appear, however, that a multi-engine rating will be required. So much for us single engine folks being interested in this thing (assuming we were in the first place).
 
Getting a multi in that thing would be easy - if you accept all the fairy dust that gets it flying in the first place. I would think the ducted fan isn't going to be as bad a boat anchor as a dead propellor (well, except that it kinda is even when it's running), it would be trivial to have them counter rotating, so there won't be a critical engine.

You couldn't feather it, but with a fan, I don't think that would be a big deal. But I'm using Peter's engineering principals of "sounds about right", it's probably totally wrong.
 
Ghery said:
It does appear, however, that a multi-engine rating will be required. So much for us single engine folks being interested in this thing (assuming we were in the first place).
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What if, and hear me out here... we just use ONE engine to drive both the ducted fans! Eh? Eh? I totes think that would work, yeah?
 
Rgbeard said:
I loved the excuse for flying 1,000 AGL. A temperature inversion.

Allllll righty!!!
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Would you climb to where it's hotter outside when you have the heater on full blast? I wouldn't... :p
 
Ghery said:
It does appear, however, that a multi-engine rating will be required. So much for us single engine folks being interested in this thing (assuming we were in the first place).
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Dude, it is fantasy land. It is more likely that I'll roll out a line of dilithium crystal powered Zeppelins.
 
Steve Costello said:
What if, and hear me out here... we just use ONE engine to drive both the ducted fans! Eh? Eh? I totes think that would work, yeah?
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I’m sure he’ll find some way to ensure a single point of failure that will kill both fans.
 
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Spoiler alert: peter plans to use a turbo Audi engine to spin a big generator via belts!

Albany Tom said:
So from an RC perspective, a tiny version of this would fly, powered by brushless motors and a lipo battery. But while in theory, ducted fans can be more efficient than props, I've never seen that happen in RC. Scaling it up to full size, to get 30HP out of each fan unit, he's going to have to put more than 22k watts into it. Or in other words, to effect the same INPUT power to the fan units, he would need the equivalent of 44 1 Kilowatt Honda generators. Electric motors small enough to fit into a 24" ducted fan exist, but they're water cooled. All to get the same input energy as a Piper Cub, with an aircraft that is supposed to weight about twice as much. Let's not forget that a Cub has about a 6' prop, or about 4.5 times the area of the ducted fans. This is just a silly design.
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It has long been known that a ducted fan or propeller can increase thrust up to 30% at a standstill (static tie-down thrust test) .... and can improve thrust a lower flight speeds .... but those benefits diminish completely at higher air-speeds and become a detriment (drag and inefficiencies) .

The best props operate in free air , using blades that are as long as possible , and rotate as slow as possible .

PM is also heading in the wrong direction if he thinks an automotive engine powering a generator to power two electric motors is his next key to success indicates his delusion is getting worse.

Ultimate has always been lots of cubic inches (horsepower at low rpm) with a direct crank mounted prop ..... if reduction is required a gear-set is most efficient with only about 3% losses .... and down the list are belt drives etc .... way down the list are electric generators and motors or hydraulic pumps and motors

.
 
The best props operate in free air , using blades that are as long as possible , and rotate as slow as possible .
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So what we need to design is not only a constant speed prop, but an extendable prop that goes from our standard 70 some odd inches and at altitude can extend to...well how big do you want it?
 
donjohnston said:
Except that the diameter of the prop doesn't change.
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That's absolutely true... at least, the diameter of the prop in its more effective orientation (as opposed to being folded).

All that said, my simple monkey brain cannot imagine how an extending prop would work... but it would be very, very cool.
 
donjohnston said:
Except that the diameter of the prop doesn't change.
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Going down a bit of a rabbit hole, but thinking about my plane (RV), or any other GA fixed-gear, why not make the gear 6-inches longer?
My guess is the engineers have probably optimized the drag vs prop efficiency. would be any easy-ish and fun experiment to do on an experimental.
 
I would really like to know who's funding him. His first prototype did exactly nothing he claimed it could do, could be handily outperformed by a ratty Cherokee 140, and crashed in a cornfield. Not a stellar record of success. Who is dumb enough to sink more money into that? Or is the designer like Bruce Wayne, with an inexhaustible supply of money?
 
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Proposing a crazy pie in the sky prototype is a good way to distract from the failure of the first prototype.
 
steingar said:
I would really like to know who's funding him. His first prototype did exactly nothing he claimed it could do, could be handily outperformed by a ratty Cherokee 140, and crashed in a cornfield. Not a stellar record of success. Who is dumb enough to sink more money into that? Or is the designer like Bruce Wayne, with an inexhaustible supply of money?
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From a post recently in this thread, it sounds like he had equity-level investors in addition to the regular deposit holders. The deposit holders were returned their money from escrow a while back. I'm guessing that the company he is working with in Idaho is buying out the equity-level investors. And maybe they have some kind of a crazy grant or angel investor backing them, which would explain the totally absurd but green-sounding hybrid electric drive idea.
 
steingar said:
I would really like to know who's funding him. His first prototype did exactly nothing he claimed it could do, could be handily outperformed by a ratty Cherokee 140, and crashed in a cornfield. Not a stellar record of success. Who is dumb enough to sink more money into that? Or is the designer like Bruce Wayne, with an inexhaustible supply of money?
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It flew and did a bunch of other things the nervous nellies here said it would never do. And I'm still wondering why folks who have no vested interested spend so much time and effort thinking about this guy. He's an absolute obsession for some here.
 
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Lindberg said:
It flew and did a bunch of other things the nervous nellies here said it would never do. And I'm still wondering why folks who have no vested interested spend so much time and effort thinking about this guy. He's an absolute obsession for some here.
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Same reason people watch "reality" TV shows. Although this one is more akin to "Jackass". You know it's going to fail, the only question is when. And this has an aviation component. So what do you expect?
 
Lindberg said:
It flew and did a bunch of other things the nervous nellies here said it would never do. And I'm still wondering why folks who have no vested interested spend so much time and effort thinking about this guy. He's an absolute obsession for some here.
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COVID. What else did we have to do over the last year?
 
EdFred said:
So what we need to design is not only a constant speed prop, but an extendable prop that goes from our standard 70 some odd inches and at altitude can extend to...well how big do you want it?
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The lowest drag prop only has one blade. Wanna go fast better get out the saw.
 
A Martin said:
It has long been known that a ducted fan or propeller can increase thrust up to 30% at a standstill (static tie-down thrust test) .... and can improve thrust a lower flight speeds .... but those benefits diminish completely at higher air-speeds and become a detriment (drag and inefficiencies) .

The best props operate in free air , using blades that are as long as possible , and rotate as slow as possible .

PM is also heading in the wrong direction if he thinks an automotive engine powering a generator to power two electric motors is his next key to success indicates his delusion is getting worse.

Ultimate has always been lots of cubic inches (horsepower at low rpm) with a direct crank mounted prop ..... if reduction is required a gear-set is most efficient with only about 3% losses .... and down the list are belt drives etc .... way down the list are electric generators and motors or hydraulic pumps and motors

.
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I love the hydraulic idea! Or pneumatic. Put a giant gas powered air compressor in the middle, then run two 30hp air motors to drive the fans. We haven't had a compressed air powered airplane in a long time. To use an air compressor, he's going to need something like a 1000HP diesel to get enough air to run the fans. Quick Google search says that a CAT 3508 could be perfect. 2100 cubic inch V-8, turbocharged. Only weighs 9500 lbs. The submarine idea sounds better now, though.
 
Albany Tom said:
I love the hydraulic idea! Or pneumatic. Put a giant gas powered air compressor in the middle, then run two 30hp air motors to drive the fans. We haven't had a compressed air powered airplane in a long time. To use an air compressor, he's going to need something like a 1000HP diesel to get enough air to run the fans. Quick Google search says that a CAT 3508 could be perfect. 2100 cubic inch V-8, turbocharged. Only weighs 9500 lbs. The submarine idea sounds better now, though.
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You'd want a C32 instead of a 3508. Same to better power density and 1 ton lighter.
 
Albany Tom said:
I love the hydraulic idea! Or pneumatic. Put a giant gas powered air compressor in the middle, then run two 30hp air motors to drive the fans. We haven't had a compressed air powered airplane in a long time.
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Every free-turbine turboprop is compressed-air powered :-) Maybe that's been the solution all along?

Nauga,
who admits it may have been in the previous thread
 
Will anything at all come of the NG? Will there even be a mockup? If Peter had any pride, this would be his exit from the public stage. Like a bad TV show that promises a Season 2, never to be seen again.
 
OneCharlieTango said:
Will anything at all come of the NG? Will there even be a mockup? If Peter had any pride, this would be his exit from the public stage. Like a bad TV show that promises a Season 2, never to be seen again.
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the most hated airplane builder has basically told us he will convert his crashed craptor 1.0 into a craptor NG mock up!
 
Lindberg said:
It flew and did a bunch of other things the nervous nellies here said it would never do.
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Yahbut there are airplane designs from the 1930's that could have outdone it in almost every respect. He accomplished nothing new. And when someone makes that level of noise claiming they're going to reinvent the wheel they tend to get a lot of attention.
 
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