how is double ender going now?

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ToddK

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Its going nowhere. It scores very high on the novelty index, but like most novelties its a solution in search of a problem.
The added complexity, weight, expense, and ongoing maintenance costs of such an airplane when balanced against a single large engine comes up very short.
 

Voidhawk9

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If only the engines were electric, the company could be swimming in cash. 🤪
It probably doesn't need any more area for take-off and landing than most E-VTOLs anyway, right?
 

saini flyer

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A good combination is a ICE upfront and an electric motor at the back. Use electric for STOL and emergency only to keep the battery weight low making the electric pusher config very lightweight. Also, charge the battery through the ICE alternator during cruise.
Best of both worlds!!
If only the engines were electric, the company could be swimming in cash. 🤪
It probably doesn't need any more area for take-off and landing than most E-VTOLs anyway, right?
 

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Cardmarc

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Or just convert a Skymaster 337 as a hybrid electric. One just crossed the English Channel as a test. Boom fronts have 2 electric motors/props
See AVWEB press release
 

rtfm

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Its going nowhere. It scores very high on the novelty index, but like most novelties its a solution in search of a problem.
The added complexity, weight, expense, and ongoing maintenance costs of such an airplane when balanced against a single large engine comes up very short.
Couldn't disagree with you more ToddK. High on novelty - check. 'a solution in search of a problem" (bloody hell, I hate that cliche) NO. It is a rather elegant solution to the problem faced by every airplane designer - that of getting the CG right. One big engine up front, and you have to put the pilot way back. One big engine at the back, and the pilot has to be pretty close to the engine to get the CG right. This is a is a better solution. The double ender puts the pilot roughly half way between the engines, and allows cheaper powerplants while putting the pilot in a panoramic viewing position in that fully enclosed glass cockpit.

In fact, the biggest drawback of the push-pull engine configuration is noise.

Why hasn't the concept sparked the imagination of builders/flyers? Because most airplane builders/flyers are so conservative it staggers belief.

Duncan
 

galapoola

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Couldn't disagree with you more ToddK.
Have to agree, if you listen to the narration in the video the designer flies in Africa. He wanted a redundant power-plant and inline so it would fly normal on one engine. He even does an in flight demo of one stopped engine and then fires the second one up. The Super Cub inspired main wing and all that flap make it very STOL, perfect for his mission. Anyone flying back country professionally or for pleasure would appreciate all of the above. I love the unobstructed bubble view. It’s not a solution looking for a problem IMHO
 

opcod

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A potate bag with an electric engine do fly well. It<s just a matter of what range you want vs what is really needed.
 

Pops

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With the high CG better have it slowed down the make a turn after landing. Even the first couple of years of the C-172 was easy to get a main wheel off the ground in a turn off the runway if not slowed down to a fast walk. Cessna lowered the fuselage of the 172 several times with shorter gear to get the CG down lower. I think 1956/57/58 is the high gear, 59/60 is a little shorter. 61-62 is a little shorter and then 1963 up . Did the same for the 182's but slightly different years. I have a couple sets of 182 gears that are different.
 

ToddK

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That’s a lot of added complexity and expense for a good view (which I do value). I think the Chinooks out there (I had one) and the Woody pusher (Especially the swamp monster) illustrate very well that CG is a non issue with with a rear engine pusher, and superior or at least very competitive stol performance can be achieved with a single engine, all with less weight, less complexity, and be less expensive.

There is nothing innovative or inspiring in the wasting of time, money, or lightness in aviation.

An engine in the back in no way requires the pilot be back near the engine. In fact the opposite is true, very often the pilot ends up setting out in front of the wing to balance the engine and tail. Adding the complexity and cost of a second engine for CG issues does not make any sense at all.

I find the supposed redundancy of a second engine in a bush/stol environment to be of fairly dubious value. If it takes two engines to drag it all in to a very tight spot, and 2 drag it out, of what use is the second engine?
 
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SheepdogRD

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The marketplace does a pretty good job of determining value, or at least commercial value. A few people or operations of some sort would probably love to buy one or more Double-enders, just as a few would love to have a Mike Patey Scrappy. Is there enough interest to make them commercially viable? Apparently not. But I suspect they could sell Double-ender plans, and probably some parts, such as the windscreen and the cowling.

The Double-ender's double-slotted flaps, developed by Doug Keller and Alec Wild, were sold as experimental and STC'd Performance STOL "Keller" flaps. The operation was purchased by Airframes Alaska, so that much of the design has definitely proven its commercial value.
I find the supposed redundancy of a second engine in a bush/stol environment to be of fairly dubious value. If it takes two engines to drag it all in to a very tight spot, and 2 drag it out, of what use is the second engine?
I agree, if STOL performance is the primary motivator. But another aspect is flying in remote or inhospitable environments. If an engine fails over jungle, or water, or places (or times) where no landing is survivable, then a second engine that can get the plane to a safe landing may be well worth the related costs.
 

Tiger Tim

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I think arguing over the merits of twin engines for STOL is missing the point of the Double Ender. My understanding is that it was more or less designed to do a similar mission to the Air Cam: get in and out of runways most normal airplanes can’t go, cheaper than a helicopter, and two engines so if one quits you can get to a safe landing place. Unlike the Air Cam, the Double Ender seems to have been intended to do it with as many Cub parts as possible.
 

Pilot-34

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Why hasn't the concept sparked the imagination of builders/flyers? Because most airplane builders/flyers are so conservative it staggers belief.

Duncan
Conservative? Lol hardly the act of building or flying already puts someone so far out in the world of wild weird and risk taker that they have used up their risk taking inclination!
 

wktaylor

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For my clarity/sanity...

'Double-ender' => Push-pull [in-line] twin engine arrangement? => [fun version] pushme-pullya

I wonder-why no one every discusses 'twin-pack' engine/motor arrangements... 2-engines/motors feed thru a common transmission to power a single propeller??? if power is de-rated [per individual power source], then, WHEN failure of one power-source occurs, the aircraft sees relatively uninterrupted operation as the 'dead' powerplant drops off line [disengages] and the 'good powerplant spools-up' to drive the prop. Reliability? Complexity? Cost?
 

challenger_II

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Its been done. The issue found was that One added the weight, complexity, and the potential fail point, of the corresponding coupling transmission.

As Robert Heinlein famously stated: TANSTAAFL.

For my clarity/sanity...

'Double-ender' => Push-pull [in-line] twin engine arrangement? => [fun version] pushme-pullya

I wonder-why no one every discusses 'twin-pack' engine/motor arrangements... 2-engines/motors feed thru a common transmission to power a single propeller??? if power is de-rated [per individual power source], then, WHEN failure of one power-source occurs, the aircraft sees relatively uninterrupted operation as the 'dead' powerplant drops off line [disengages] and the 'good powerplant spools-up' to drive the prop. Reliability? Complexity? Cost?
 

gtae07

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Why hasn't the concept sparked the imagination of builders/flyers? Because most airplane builders/flyers are so conservative it staggers belief.
Conservative? Lol hardly the act of building or flying already puts someone so far out in the world of wild weird and risk taker that they have used up their risk taking inclination!
As Douglas Adams put it,
I've come up with a set of rules that describe our reactions to technologies:
1. Anything that is in the world when you’re born is normal and ordinary and is just a natural part of the way the world works.
2. Anything that's invented between when you’re fifteen and thirty-five is new and exciting and revolutionary and you can probably get a career in it.
3. Anything invented after you're thirty-five is against the natural order of things.
 

REVAN

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The high mount engines are not going to be good for stopping, or general ground stability. I think both are important for effective STOL operations.

Cost is a big factor for bush flying, as accident rates can be high, and this configuration is more expensive than a traditional configuration. As you lower the stall speed, the risk of a fatal forced landing from an engine out situation is lowered. This decreases the value of a multi-engine architecture. Then balance the odds of an engine-out situation where a safe landing is not possible vs. the odds of wrecking the plane on landing or takeoff due to pilot error and the cost of damages/repairs in each situation. I'm thinking that the multi-engine STOL configuration doesn't start to pay dividends in the equation unless you spend a significant amount of time flying under 200 feet above hostile terrain. If you don't need to do that and are willing to use altitude for a safety device, the traditional single engine arrangement will likely be preferable.

Also, don't underestimate the value of looks. This plane looks very different from a typical bush plane, a genre that already has an overactive thread of nostalgia running through it. There is the old saying that, if it looks good, it will fly good. I've observed evidence there is an apparent spin-off that some seem to have adopted; if it looks ugly, it will fly slow. IMO - This spin-off lacks wisdom and is often not true. While a design may be considered "ugly" because it isn't very streamlined or elegant looking, these attributes don't assure slow flying, or STOL capabilities. They will likely only prevent it from having the ability to go fast.

Anyway, some designers feel they have liberty to make an ugly plane if it is intended to be a STOL plane. I tend to think this is a mistaken attitude. While, I'm a strong proponent of the axiom form follows function, a good looking plane will sell better, so long as it delivers on performance.
 
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