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tspear

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I think it is interesting that they have focused on what is probably a moderate/achievable mission. Short range, lower speeds, 9 passengers, likely limits crew requirements also....
Also, they seem to have been developing quietly for a while and only are going public when they are getting ready to test the prototype.

Tim
 

12notes

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Stumbled on this while looking for a better photo of the tail wheel assembly, still not a technical article, but a bit more information:
https://thepointsguy.com/news/eviation-alice-electric-plane-tour/

"the aircraft can continue to fly with just the rear motor engaged. If one wing-mounted motor fails, the other will be disabled to maintain stability, and additional electric power can be diverted to the rear motor so the plane can continue its flight."

The customer they have lined up, Cape Air, has short haul routes mostly under 240 miles, and they claim to be able to recharge an hour's worth of flight in 30 minutes. If the plane is close to the 240 knot cruising target, this would keep turnaround time reasonable.
 

Dan Thomas

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I don't think the FAA has the criteria in place to certify an electric airplane.
Probably not. The first applicant will have to work with the FAA to write up some regulations. That will delay things considerably, but that first applicant might get some free certification out of it.
 

mm4440

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Are there links to those articles you wrote? Would be interesting.

There was crosswind gear available on the Cessna 170 and perhaps some other airplanes. It castered to discourage groundlooping, but was not widely received. You don't see it on any production taildraggers these days.

Another issue I'm wondering about with steerable taildragger mains would be the forces required to control them through the rudder pedals. And the corollary to that is the relative lack of weight and traction on the tailwheel due to its long arm from the CG.

So many ideas have been tried and found wanting. Aviation history--even in my own 66 years--is full of enthusiastic propositions that just never panned out. One of the big mistakes inventors make is to publish their ideas with all the performance projections, and when (if) the machine becomes reality it usually fails to reach that standard. That just brings ridicule and disillusionment. And then there's the already-mentioned investment scams that are particulary successful among the uninitiated. Among us older guys the Moller Aircar is the classic example of that: https://en.wikipedia.org/wiki/Moller_M400_Skycar

A couple of excerpts:

The Moller Skycar is a prototype personal VTOL (vertical take-off and landing) aircraft – a "flying car" – invented by Paul Moller who has been attempting to develop such a vehicle type for more than fifty years.[2] As of 2018, no Moller air vehicle has successfully flown in free, non-tethered flight.

After forty years and $100,000,000 in expenditure[4] the Skycar demonstrated tethered hovering capability in 2003.[5] It has been extensively marketed for pre-order sale since the 1990s as Moller attempted to raise more money for development.

In April 2009, the National Post characterized the Moller M400 Skycar as a "failure", and described the Moller company as "no longer believable enough to gain investors".[6] On May 18, 2009, Paul Moller filed for personal protection under the Chapter 11 reorganization provisions of the federal bankruptcy law[7] and it is unknown how this will impact the fate of his ideas; Moller International itself did not file for bankruptcy but reduced operations.[8]


That sort of stuff--and it's not alone at all--tends to make seniors skeptical. Way back in the late '70s a friend was all ready to send his deposit to Moller, and I couldn't dissuade him. Some folks are just too optimistic and trusting. I don't know if he ever sent the money. It's long gone if he did.

All through my growing-up years, long before the internet, I read the magazines aimed at guys like me. Mechanix Illustrated. Popular Mechanics. Science and Mechanics. Popular Science. All of them, every three months or so, had another breathless article about the newest revolutionary airplane or helicopter or engine. Years of that sort of thing. I can count on one hand the machines that actually made it: The Wankel Rotary engine. Rutan Varieze and its derivatives. Some others, like the Beech Starship, made it but were failures to the point that Beech bought them all back. So, today, we're left with horizontally-opposed four-bangers and a few European diesels that are still struggling to overcome technical issues. Most brand-new light airplanes are of conventional tractor configuration. Helicopters are still using the same controls they did 70 years ago; the real advances are in blade articulation technology--elastomerics, flex straps and all that.

If there will be any really revolutionary machines I believe they'll be VTOLs. Big quadcopters. And they'll need much larger battery capacity than we have now, and some serious forms of redundancy; they don't autorotate like a helicopter. The drive systems MUST work absolutely reliably.
https://www.youtube.com/user/MurryR100 The link to my EAA " Experimente"r article is not there anymore,will try to find.
 

BBerson

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A locked tailwheel is useless if still in the air (or barely any weight is on it) when landing.
A pilot sometimes lands on only one wheel, especially in a crosswind. That one wheel needs to be slightly behind the CG to be self correcting.
 

mm4440

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If the wheel or wheels in front of the cg are free to caster there will be no ground loop. The fixed tailwheel acts like the vertical stab. If it is in the air you have to use the rudder to fly down the runway until it comes down. There are more details involved.
 

BBerson

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Sometimes the rudder is ineffective as well. Then try differential brakes. Trouble is differential brakes sort of impedes takeoff in an underpowered motorglider. (see avatar)
 

narfi

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Seems for this configuration the tailwheel could help prevent prop strikes on the rear prop.

It is finished pretty plush for a 'prototype'... nice leather passenger seats with wireless charging stations, swivel seats for looking out the windows, etc.....
 

BBerson

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It's probable purpose was as a sales mockup instead of flight prototype. The article in post 1 said prototype number 2 is under construction. That means prototype 1 likely wasn't flyable, is my guess.
 

narfi

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according to wikipedia (which of course should be taken with a grain of salt)
Eviation hopes to secure EASA airworthiness approval before the end of May, to fly Alice from Vannes or nearby Nantes, ahead of Paris air show
I think the current pictures are from the paris air show that just finished? but i didnt find any news about any initial flights taking place.......
 

12notes

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The article I posted stated that the prototype in Paris was airworthy. I've seen a few other articles stating the plane in Paris is fully functional, and that particular plane is heading to Arizona after the show for flight testing later this year.
 

Dan Thomas

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Seems for this configuration the tailwheel could help prevent prop strikes on the rear prop.
But at the same time, the prop won't be too far off the ground, either. One of the real drawbacks of pushers is the risk of prop damage by loose debris kicked up by the tires, as well as water splashed up by the wheels on a really wet runway. Trikes with tractor props have enough trouble as it is. I used to watch my apprentices running up airplanes after inspections, and would watch the surface under the prop. If there was water (a puddle), a waterspout would form and the puddle would disappear. This was with around 10" of prop tip/ground clearance. If there was sand or small stones, the vortex ring around the prop would sweep that stuff forward from a foot behind the prop, under it and then up into the prop. Kinda hard on the metal blades. Taildraggers with tractor props tend to get the best propeller life. Lots of ground clearance.

This one was built at least 20 years ago as an aircraft for unimproved strips--rough stuff. I can't imagine that propeller life was very good at all.



 
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tspear

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But at the same time, the prop won't be too far off the ground, either. One of the real drawbacks of pushers is the risk of prop damage by loose debris kicked up by the tires, as well as water splashed up by the wheels on a really wet runway. Trikes with tractor props have enough trouble as it is. I used to watch my apprentices running up airplanes after inspections, and would watch the surface under the prop. If there was water (a puddle), a waterspout would form and the puddle would disappear. This was with around 10" of prop tip/ground clearance. If there was sand or small stones, the vortex ring around the prop would sweep that stuff forward from a foot behind the prop, under it and then up into the prop. Kinda hard on the metal blades. Taildraggers with tractor props tend to get the best propeller life. Lots of ground clearance.

This one was built at least 20 years ago as an aircraft for unimproved strips--rough stuff. I can't imagine that propeller life was very good at all.

If you are doing a static ground run up; the vortex pulling stuff up applies the same to a pusher and a tractor plane.
The difference between the two really is either ground clearance or when moving. I do not see how the static test matters.

Tim
 

Dan Thomas

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If you are doing a static ground run up; the vortex pulling stuff up applies the same to a pusher and a tractor plane.
The difference between the two really is either ground clearance or when moving. I do not see how the static test matters.

Tim
I was trying to get a point across: how much ground clearance can a pusher prop at the very end of a taildragger's fuselage have?

And is that clearance requirement the reason the airplane's ground attitude is so flat?

Geometry is such a pain, isn't it?
 

tspear

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I was trying to get a point across: how much ground clearance can a pusher prop at the very end of a taildragger's fuselage have?

And is that clearance requirement the reason the airplane's ground attitude is so flat?

Geometry is such a pain, isn't it?
Assuming I recall correctly, my Cirrus has a lower ground clearance on the prop as the Velocity Twin I was considering when sitting still. But yeah, on takeoff when you raise the nose, I am willing to bet the Velocity props are lower to the ground.

Tim
 

BJC

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Seems for this configuration the tailwheel could help prevent prop strikes on the rear prop.
Yes, but the overall configuration appears to severely limit the AoA on takeoff and landing.

It will be interesting to see if, as they wrote, it flies this fall.


BJC
 

mcrae0104

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A locked tailwheel is useless if still in the air (or barely any weight is on it) when landing.
A pilot sometimes lands on only one wheel, especially in a crosswind. That one wheel needs to be slightly behind the CG to be self correcting.
BB's right. With the proposed configuration, when taxiing with a crosswind, the plane will crab into the wind with the tailwheel skidding merrily behind over the pavement. The diagrams in the article are interesting but the self-correcting side force the tailwheel can generate is limited to the weight that is on it (with an ideal friction coefficient of 1).
 
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