Switchblade Flying Car

Like many of these unbuilt conceptual designs that are only vaguely air or ground vehicle (or both) I am very sceptical they will even work as either or both, let alone be approved for use.

Link

The Switchblade has side-by-side seating for two, room for over 100 pounds of luggage (golf clubs, etc.), a wide cabin, and the power-to-weight ratio of a 2017 Corvette

Given the body and wing shape and a 190hp engine and 794kg takeoff weight the lift to weight ratio just seems too low to me.

Any thoughts from our aeronautical members, is this even practical?

OVER 200KPH ROAD DRIVING SPEED? Seriously, this just sounds like fantasy to me.

I don't believe that will fly.....the wings are too small, it would need a jet engine and have a 300 mph takeoff speed...

..."At just over 5 meters long, the new model can reach speeds of up to 515 km/h while having a range of 370 km. It is powered by a Quantum Turbine System which gives a thrust of 265lbs (120 kg), allowing it an impressive maximum carrying capacity of 200 kg while the plane itself only weighs 188 kg."..

This is the above mini-jet...

For piston-propeller aircraft:
Thrust = 550 * bhp * prop efficiency / velocity
- thrust is in lbs
- 550 is just a conversion factor
- bhp is engine brake horsepower
- prop efficiency is a max of about 90%
- velocity is in ft/s

So on the prop driven plane let's say we need,, how much thrust?

http://www.airliners.net/forum/viewtopic.php?t=739339

Thrust X .66 = BHP

Wing surface area required?

https://www.ajdesigner.com/phpwinglift/wing_lift_equation_force.php

The BD5 was originally a 70hp two stroke with a top speed of about 170mph.

But it did have a fairly high stall speed.

And would it have any stability problems while driving, like the Reliant Robin?

https://www.youtube.com/watch?v=QQh56geU0X8

A Reliant Robin with a top speed of 120mph? I think it would be worse: The weight of the ducted fan and its thrust are over the back wheels so at any speed the nose will try to lift (it is an aeroplane after all) and make the thing unsteerable. Some form of retractable splitter to create downforce over the nosewheel would be necessary. The Robin didn't handle at all well even though it had the engine behind the front wheel.

If the thrust alignment is horizontal and above the rear wheel would that not create a downforce on the front wheel? The Reliant's handling problem was not so much the front wheel lifting as the mass of the engine being sufficiently high to cause a rolling moment in turns.

If the main part of the thrust is above the roll centre the force would be downwards. Look at the effect of flaps. With a high wing, when you lower the flaps the nose pulls up. With a low wing it pulls down. Remember: The Principle of the Lever. (1st year Physics.

Meoowwrr....Marum.(Die schachspielen Katze)

The forward swept wings tell me this is an unproven concept vehicle only.

I wait for the first Alcubierre drive craft. Dream BIG!

Vehicle, I don't need no stinkin' vehicle!

OK.... I don't WANT that........ I NEED that!!!! Too COOL!!!!!!!

Hmm, you might have a long wait for that Alcubierre drive craft!

Tell that to the Ruskies. The Sukhoi SU 47 seems to work pretty well.

Grrrrooowwwwlll....Marum.(Die schschspielen Katze)

The only SU 47 ever built was a test bed plane, just like the two X-29 built by Grumman for NASA. The KB SAT SR-10 is a forward swept prototype offered as a jet trainer but this seems paradoxical to me. Training a pilot's muscle memory to respond to a very atypical wing geometry seems odd to me.

I don't dispute that there are some significant advantages (agility to name but one) for a forward swept wing that will continue to bring this atypical wing geometry back from time to time. Remember that agility and instability go hand in hand. An agile car/plane is only desired in an animation.

Interestingly KB SAT is modifying the SR-10 to an AR-10 which is an unmanned variant. A high agility remotely piloted aircraft seems like a viable design, particularly for air superiority. That is if one can mask the RF communication.

It has to be made of ultra lite composite, carbon fibre. One thing about carbon fibre cars: it is used extensively through out motorsport REALLY doesn't like high force impact. Given it looks to be about the size of a (not so) Smart Car it is probably as safe, not at all according to the aero posters, on the ground as it is in the air.

I also do not see any flight control surfaces. So unless they have a new way to implement the Wright Brothers wing warping (flexible skin and pneumatic bladder) the animator left out some crucial information.

Righto. I was originally a Motor Mechanic.

First let's deal with it as a car. A three wheeler of this configuration will give you lots of understeer, as well as instability in bumpy corners. That is why most three wheelers (Morgan, Messerschmitt ,etc) had two front wheels and one rear. The makers claim 190bhp. Thus 200kph., seems a little high.

Now as an aeroplane. (Flying is a lifetime passion since I was eight or so.

The makers claim a wing loading of 26 Psi. (Spitfire 28Psi, Beechcraft Baron 26Psi) A Cessna 182 is 16.9Psi. With wingspan of 35'10" and an area of 174 sq ft, This device has a wing area (calc. by me) of 144 Sq ft, and a wingspan of 30 feet. So I would expect it to be of only average maneuvreability. The makers claim high lift wings. High lift = high drag. eg. Cessna rectangular wing. From their website, the wing does not point forward, it looks dead straight. The photo, may be with the wing partly deployed. However that design has a lot of advantages, with the disadvantage of a narrow operating window. When, at trans-sonic speed, the wing root starts to distort, the aircraft rapidly loses controlability. (over Mk 3) I don't think that, would worry this device.

The landing and take off roll seem a tad long, and the top speed a little ambitious. Stall speed seems a tad high.

So, to sum up, from this very brief assessment. It is like most such hybrids, and as such, so too, is the problem with mermaids. They are not fish enough to eat, or woman enough to have sex with.

Purrr....Marum. (Die schachspielenkatze)

Nope....

Yep....

Found this from 2009...

I guess it's taking a while to get off the ground....haha

Right. I notice they have included a "Canard" in the redesign. I was going to mention that in my first posting, but I thought of the KISS principle.

In the hands of novice and inexperienced pilots a canard makes them almost un-stallable, provided the canard-wing stalls before the main wing. Also,, it improves performance , by reducing drag, thereby eliminating the need for a tail wing. It is also a great idea on "Pusher-prop aircraft. For basic info on Canard-wings see: http://www.boldmethod.com/learn-to-fly/aircraft-systems/canards/

Purrr....Marum. (Die schachspielen Katze)

Latest iteration...

..."Plans also call for the $140,000 three-wheeled, carbon-fiber vehicle to make its first public flight this summer. MARCH 21, 2018 "...

..."According to Samson Sky’s projections, the three-wheeled carbon-fiber vehicle will accelerate from zero to 60 mph in 6.5 seconds on the ground and reach a top speed of more than 100 mph. In the air, it will cruise at 155 mph and fly as fast as 175 mph. The Switchblade will achieve 35 miles per gallon of regular unleaded automobile gasoline on the road, and it will burn only nine gallons per hour when flying. It is 16 feet 9 inches long and only about 6 feet wide, so it will fit in a standard house garage."...

https://robbreport.com/motors/aviation/samson-sky-switchblade-flying-car-to-road-test-2784310/

General characteristics

• Crew: one
• Capacity: one passenger
• Length: 16 ft 8 in (5.08 m) in ground mode, 20.2 ft (6.2 m) in air mode
• Wingspan: 26 ft 9 in (8.15 m)
• Height: 5 ft 1 in (1.55 m)
• Wing area: 67 sq ft (6.2 m²)
• Gross weight: 1,550 lb (703 kg)
• Fuel capacity: 16 U.S. gallons (61 L; 13 imp gal)
• Powerplant: 1 × Suzuki Hayabusa four cylinder, liquid and air-cooled, four stroke aircraft engine, 170 hp (130 kW)

Performance

• Maximum speed: 200 mph (322 km/h; 174 kn) in the air, 100 mph (161 km/h) on the ground
• Cruise speed: 160 mph (257 km/h; 139 kn) in the air
• Stall speed: 67 mph (108 km/h; 58 kn)
• Range: 345 mi; 556 km (300 nmi)
• Wing loading: 23 lb/sq ft (110 kg/m²)

Avionics

• 7″ Dynon Skyview
• 10″ Dynon Skyview
• Garmin AERA 550
• Garmin GMA 340
• Garmin SL30
• Garmin GTX 330.

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

Well it is now August of 2018 but still no full scale model has been flown, at least that I can find. A few months and even a year delay should not be worrisome for a new aeronautical vehicle.

The full scale mockup/prototype from the cited Robb Report does seem to have flight control surfaces but no canard.