I am in the camp that hopes that disappointing is all that it is.

Chris, here is my simplistic math approach.

Best in class drag, 300 hp to get 300 ktas at FL 240 standard atmosphere. Total drag in English units is somewhere around 275 lbs. It will take incredible execution on design and construction to get airframe AND cooling drag to this level. This also assumed a much lighter airframe than he has now, and an operating weight of 3000 lbs.

Best in class BSFC demonstrated for aircraft Diesel engines = 0.35 or 15 gph for 300 hp. For him to achieve this with a junkyard Audi would be an amazing feat worthy of admiration.

Note that to meet the “unrealistic” scenario I posted above, he needs to meet both of these criteria. That will give him 300 knots on 15 gph while making 300 hp. This is the fairytale math that probably got this started and I would guess is similar to what you fell in love with. BUT...

I am not sure he is going to able to cool that engine at the output, and I would be really surprised if he was able to do that without higher cooling drag. Higher weight is going to mean higher drag. Another 20 lbs for induced drag? Add even more if it really will carry 200 gallons of fuel and passengers. Then a larger wing to keep wing loading semi-reasonable, adding how much more drag? Start to do the math and you will soon need 360-400 hp to cruise at 300 knots. Or more! (Plot your polar if you need that visual, but we are talking about a single point on the curve, 300 knots so why do you keep talking about polars?).

So, back to the engine. Now it needs to make 360-400 hp continuous (without self destructing and while keeping cool.) That’s 18-20 gph at 0.35 bsfc, but he won’t do that well. 0.38 to 0.42 is where I would guess he will end up. Now I have a fuel consumption estimate of 19.5 - 24.0 gph.

That’s best case IMHO, and you can see from there the range falls apart fast. The engine is being pushed very hard, if he can even get it there. Wing loading a max gross will be very high making it a handful to fly. Take off and landing speeds with push higher and so will rolling distances. Engine out scenarios will have extreme lethality risk. And so on.

Sorry, but I think this is the reality IF EVERYTHING GOES WELL and it sure doesn’t look like he has the proper expertise for even that to be likely. We will see.

Just saying:
You show up a couple of weeks ago
Obviously very smart, with way too many fast and precise answers.
You supposedly fly a Pilatus PC12ng, which is no joke.
Only post about "The Raptor"
Defend him with very strong facts.
Sign :"Fly Raptor, fly"
Hum...
Don't get me wrong, I love the fact that this Raptor guy is trying hard to make his dream come through. But Gravity and basic laws that govern on this earth are still in effect here.
His claims were ludicrous to start with.
For me, once you claim something, you need to do it. If you can't, it means only 2 things:
You are a liar, or you are incompetent.
Sorry, the "dreamer" category is closed past the age of 15, or the minute money changes hands.

I hear ya... You said "Best in class drag" What does that mean?

It means the lowest total drag coefficient I could find for a 4 place composite aircraft with highly laminar wing and turbocharged piston engine at roughly 3000 lbs operating weight measured at a lower altitude than being discussed.

Also, here is a loaded question nearly all pilots will get wrong:

A skilled race pilot does some laps at Reno hitting 200 k IAS on the straight aways in his slick experimental powered by a high performance turbo charged piston engine. Then, he flies home at FL 240 at 200 k IAS. Is the drag higher, lower or the same on the way home?

Pilots will almost always answer the same, because that’s the common teaching about IAS and a good enough estimate for what they need to know. The reality is on the flight home, the engine is generating more hp due to higher TAS. That extra hp plus the altitude effects increases the required cooling drag (cowl flaps?) If you plot minimum drag vs altitude for a turbo piston engine at a given IAS, it is not flat but a curved line.

"It means the lowest total drag coefficient I could find for a 4 place composite aircraft with highly laminar wing and turbocharged piston engine at roughly 3000 lbs operating weight measured at a lower altitude than being discussed."

Pusher or tractor config?

1.) Is the boundary level airflow velocity over the fuselage/wing root/empennage of the IV-P higher or lower than the same over the Raptor?

2.) Why?

3.) Implications to parasitic drag?

4.) Parasitic drag is what percentage of total drag?

5.) Parasitic drag increases is linearly with speed?

Next.

Raptor belt drive got nothing on this
http://www.geversaircraft.com/ac/propdrive.htm

The polar must be a bear.

Hey, Chris, one more quick question: why does the headset in your avatar say “esoB?”

The minimum number from a data set that included a number of configurations including a number of pusher prop canard designs. In addition to being hung up on the polars, you also seem to be fixated on the drag reduction from laminar flow over the fuselage. In practice it is a lot smaller than you seem to think and is typically offset by other factors. For example, the two big vertical stabilizers on the wingtips of the Raptor. They may have a positive impact on induced drag and increase the effective AR of the wing, but if you look at your polars, that is a fairly small piece of total drag. On the flip side, they add significantly to parasite drag as IAS approaches 200 knots.

Pushers are hardly groundbreaking new technology. The earliest airplanes were pusher designs, so the tractor config is the relative new comer. The initial reason to put the engine in front was for crash survivability with wooden stick construction, but as airframes became stronger, the tractor design still remained more common. Even amongst fighters and air racers where every bit of speed counts. Think about that. If the pusher canard was dramatically lower in drag, wouldn’t pusher designs dominate every class at Reno where they are allowed? They clearly don’t.

The airframe my minimum possible drag number came from was in fact a tractor config with a small area high aspect ratio laminar airfoil wing that had lower overall drag than any pusher design with available data. It was also unpressurized, lighter, and optimized for lower altitudes where cooling drag could be reduced. Based on how that airframe compares to the Velocity line and other pusher configs that are EXTREMELY similar to the Raptor, it isn’t hard to figure out where the Raptor will slot in without some innovative drag reduction approaches that I see no evidence of.

I have given you more than enough. If you remain convinced I am wrong, share YOUR numbers and sources. Explain YOUR reasoning. So far all you have shared are a bunch of questions challenging others, assertions about drag polars but no actual drag polar for the Raptor, and pictures of variable definitions and formulas with no numbers.

The minimum number from a data set that included a number of configurations including a number of pusher prop canard designs. In addition to being hung up on the polars, you also seem to be fixated on the drag reduction from laminar flow over the fuselage. In practice it is a lot smaller than you seem to think and is typically offset by other factors. For example, the two big vertical stabilizers on the wingtips of the Raptor. They may have a positive impact on induced drag and increase the effective AR of the wing, but if you look at your polars, that is a fairly small piece of total drag. On the flip side, they add significantly to parasite drag as IAS approaches 200 knots.

Pushers are hardly groundbreaking new technology. The earliest airplanes were pusher designs, so the tractor config is the relative new comer. The initial reason to put the engine in front was for crash survivability with wooden stick construction, but as airframes became stronger, the tractor design still remained more common. Even amongst fighters and air racers where every bit of speed counts. Think about that. If the pusher canard was dramatically lower in drag, wouldn’t pusher designs dominate every class at Reno where they are allowed? They clearly don’t.

The airframe my minimum possible drag number came from was in fact a tractor config with a small area high aspect ratio laminar airfoil wing that had lower overall drag than any pusher design with available data. It was also unpressurized, lighter, and optimized for lower altitudes where cooling drag could be reduced. Based on how that airframe compares to the Velocity line and other pusher configs that are EXTREMELY similar to the Raptor, it isn’t hard to figure out where the Raptor will slot in without some innovative drag reduction approaches that I see no evidence of.

I have given you more than enough. If you remain convinced I am wrong, share YOUR numbers and sources. Explain YOUR reasoning. So far all you have shared are a bunch of questions challenging others, assertions about drag polars but no actual drag polar for the Raptor, and pictures of variable definitions and formulas with no numbers.

"Aerodynamics are for people who can't build engines."

--Enzo Ferrari

“We can make anything fly if we have a big enough engine and you have a big enough budget”

Matt Fine,
was that "optimum" airframe catbird?