Roadable aircraft

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Victor Bravo

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Sorry to repeat myself here, but duty calls. I've been awarded a $50,000,000,000 grant from the World Common Sense Foundation, for the task of prying all the complexity and needless futuristic vaporware nonsense out of people's minds and putting simplicity and "do-able" back in. I've been issued an Anti-Moller Ray Gun and I'm not afraid to use it !

If you want to make a roadable aircraft you have to go bigger, not smaller. You need something the size of a large minivan or even a full size old Ford Econoline van. But fabric covered tube or a very light composite box. The wings and tail go inside the back of the van where you have room to store them, and they won't get !(#*$ damaged, and they don't have to have all that !)#*% heavy mechanism for folding and unfolding the parts, telescopic wing spars, etc. with the push or a button.

As for power, if you really want to go modern hi-tech, then have one IC engine driving an efficient, but current technology alternator. Build small LIGHT electric motor components directly into the road wheels (brushless outrunner) to power the vehicle on the ground. A larger electric motor can drive the propeller for flight. A MODEST battery pack, or a bank of capacitors, can store enough energy to assist takeoff and smooth out the drive train, but the primary power comes from the IC engine driven alternator, NOT 1000 pounds of batteries carried around.

This type of roadable aircraft is inherently less efficient than an equivalent car or aircraft, of course. No way around it...you are carrying parts of a car when you are flying, and parts of an airplane when you're driving. But because you went larger instead of smaller (perhaps 180-200 sq. ft of wing), you now have a reasonable amount of lifting area available. Because you allowed yourself the 18 foot length of a van instead of a sportscar, four 12 x 4 foot wing panels can fit inside the vehicle, giving you the area, span, and aspect ratio to have an aircraft that climbs well on reasonable power. The length of the vehicle also allows you to have a longer tailboom or tailcone, putting the tail at a reasonable distance behind the wing for safe flight characteristics.

This configuration allows you to lay out a somewhat conventional aircraft with a longer span, or even look into the Rutan ATTT tandem wing for a "three surface" configuration. The 3 surface layout allows you to use high lift devices on the main wings if the trade-off between complexity, weight and CL justify it.
 

bmcj

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:gig: I want to see you use your Anti-Moller Ray Gun. (Better do it quickly before it goes on the California assault weapon ban list.)
 

BBerson

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four 12 x 4 foot wing panels can fit inside the vehicle, giving you the area, span, and aspect ratio to have an aircraft that climbs well on reasonable power. The length of the vehicle also allows you to have a longer tailboom or tailcone, putting the tail at a reasonable distance behind the wing for safe flight characteristics.
Four wings?
 

Victor Bravo

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Four wings?
No, four (12 foot max) wing panels that are assembled as two wings with a total span of 48 foot (max).

OR if someone wanted to explore a 3 surface aircraft config. (using a forward wing, rear wing, and elevator) they could essentially use this method to have two main wings of 24 foot span. The three surface configuration allows larger flaps and flap deflections than conventional airplanes. So you can often use higher lift devices and high lift coefficients on the wings, and yet still have a lightly loaded tail with plenty of trim authority.

The point was that regardless of the wing configuration, if you have an 18 foot long vehicle, the rearmost 12 feet can be used to store the wings in four pieces like the larger competition gliders do nowdays. Relatively simple overlapping spars that are held together with simple shear pins, instead of a huge electro-mechanical folding and locking mechanism.

Looking at most of the other roadables, they try to use shorter spans, or they try to use complex folding or swinging wings that are smaller than they otherwise could be.
 

Victor Bravo

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No, Deszo is a great guy and very enthusiastic, and he's a member of our local EAA chapter (the actual photographs in that article are in our EAA hangar)... but his concept is different than I am saying.

The concept I mentioned for a three surface airplane is much more along the lines of this:


scaled-attt.jpg
 

BBerson

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No, four (12 foot max) wing panels that are assembled as two wings with a total span of 48 foot (max).

OR if someone wanted to explore a 3 surface aircraft config. (using a forward wing, rear wing, and elevator) they could essentially use this method to have two main wings of 24 foot span. The three surface configuration allows larger flaps and flap deflections than conventional airplanes. So you can often use higher lift devices and high lift coefficients on the wings, and yet still have a lightly loaded tail with plenty of trim authority.

The point was that regardless of the wing configuration, if you have an 18 foot long vehicle, the rearmost 12 feet can be used to store the wings in four pieces like the larger competition gliders do nowdays. Relatively simple overlapping spars that are held together with simple shear pins, instead of a huge electro-mechanical folding and locking mechanism.

Looking at most of the other roadables, they try to use shorter spans, or they try to use complex folding or swinging wings that are smaller than they otherwise could be.
I bet the glider wings weigh more than the fuselage. Weight doesn't matter much for a glider but does for an airplane.
That would be a huge weight penalty for an airplane, even more for a flying moving van. :gig:
 

jedi

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FYI - Plane Driven is in the process of modifying a Just Aircraft with a conversion similar to the prior Glasair Sportsman conversion. Sportsman was too expensive. JA will be faster and easier to convert from Road to Air to Road.
 

Xanadrone

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http://www.autocar.co.uk/car-news/new-cars/world’s-first-production-road-and-air-legal-flying-car-sale-prices-specs-pictures

...is the latest announcement made by the [crazy] :gig: dutch company PAL-V about the imminent (2018) commercialization of their "legal flying car" in the final form, following prototypes presented in 2009 and 2012 - that you know already.

This 2-places 3-wheeled tilting (on the road) auto-gyro has two separate engines (100 HP on road and 200 in the air) and shoud cost a whooping 600K USD - way too much in my opinion, but this is just one of the issues prone to further discussion.

P.S. I was tempted to post it in the "motorcycle of the air" thread, but it ain't one IMHO. I'll be back though on that specific - and interesting - topic, because I found its goals were superposed to some personal ideas during my long absence here.

Please be well all
X
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32721695732_24313d0597_oweb.jpg
 

Topaz

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Website lists the "initial" sales price at £425,000 which, at this morning's rate, is about $529,000 and change.

There's just not that much value there, IMHO.
 

autoreply

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I know a bit more about the company than public.

They got it right. It'll remain a niche for the decade to come.

But at least they start selling for a profit. Best way to bankrupt a company is to hype and sell too cheap. Eclipae anyone?
 

Victor Bravo

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The point is that however many of them that they do sell will actually be flying "normally" and do what was advertised. No scams or rip offs. The thing looks like it will do what they say it will do, and that an average gyro pilot will be able to buy one and use it as a daily flying car to whatever the allowable limits of their country.

Some of us may remember that cell phones were pretty expensive in the beginning too. But once they started to do what they claimed to do, with some degree of reliability, the prices came down.

Also, let's remember the cost of certifying a traditional airplane. Not many new airplanes for under 600K these days. I believe a Cirrus SR-22 is priced similar to the PAL-V.
 

Xanadrone

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You've almost convinced me it's a bargain (@bmcj & @Topaz made me check my bank-account in a hurry ;) - luckilly i had the 529,000 $ left, but with the european-style comma... so it wouldn't be enough for a PAL-V tyre.)

A bit more seriously now, I'm sticking even harder to my opinion after visiting http://www.planeandpilotmag.com/article/gyroplanes-buyers-guide-2015/#.WKQWw9J_uHg and seeing prices between 60-90K $ for gyros with good performance, enclosed cabins and similar Rotax engine.
OK, they can't make the trip home-airport, but wait a minute... i'm wondering if our veteran colleague @Aircar contributed to this design, 'cause PAL-V states it clear: "Dont't EVER land on the road!" :gig:

Anyway, I remain skeptic about the "democratisation of the skies" for zig thousand motives, linked not only to the ongoing orwellian societal control.
...And finally much more serious: I do admire the guys from PAL-V for their inventivity and stubborness "to make it tangible" at any price (pun intended), though I doubt that this slightly modified auto-gyro will have more relevance for the GA progress than a handful of golden-diamond plated Bentleys sold to sheiks for the future of the automotive industry.
An exotic niche occupier it may be, but that's all.
 
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