If you could have a 2-place, ~200 hp (total), twin experimental that would perform as well as a single with the same operating costs and identical build price, would you prefer it when flying in the backcountry?

And assume: IFR capable, high performance, turbo-normalized, with a high single-engine service ceiling.

In other words, does the fact that it's a twin turn you off because of the extra flying requirements, or does the added safety of the extra engine in the backcountry make up for the complexity?

or does it turn you off because of the increased maintenance cost of the twin?

DAMN!! Not what I was thinkin... cuz Twins whould be cool at least once.....

For me it's a turn off
Reason is it doubles the odds of an engine failure and I do a lot of low slow flying and take offs
Rather have less chance of failure or if I have one just go right to focusing on the landing.
But that's just me probably depends on type of flying u do
If I did a lot of high night cruising in marginal weather I would have a different answer.

soyAnarchisto wrote:or does it turn you off because of the increased maintenance cost of the twin?

Read again and he states based on the same operating cost...

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I might be about to make an "ass out of u and me" when I _assume_ that the two engines in your scenario are "fair" meaning they are unique and the probability of failure is not dependent on another. I think this is the correct assumption - unless you consider fuel delivery, electrical, or control issues - which will screw you and should be properly designed with redundancy and complexity (and cost) of the systems.

If that is true - and feel free to argue if its wrong - then Blu - adding a second engine does not "double" your chances of engine failure. In fact it drastically decreases your chances of having a bad day.

Consider for the sake of argument that the probability of failure of an engine is 1 in a million or 1/1,000,000. Probability of engine working is the inverse then 999,999/1,000,000.

The math works like this:

The are only 4 possible outcomes - only 1 of which means you have a bad day. Again assuming the plane climbs or maintains altitude (critical engine) with a single engine.

1) Engine 1 works, Engine 2 works
2) Engine 1 fails, Engine 2 works
3) Engine 1 works, Engine 2 fails
4) Engine 1 fails, Engine2 fails

Probability of outcome 1 is: (999,999/1,000,000) * (999,999/1,000,000) = 99.9998% - have a good day
Probability of outcome 2 is: (1/1,000,000) * (999,999/1,000,000) = 0.0000999999% - clean your drawers scared shitless
Probability of outcome 3 is: (999,999/1,000,000) * (1/1,000,000) = 0.0000999999% - clean your drawers scared shitless
Probability of outcome 4 is: (1/1,000,000) * (1/1,000,000) = 0.0000000001% - fly it all the way to the crash site

In single engine, the math is easier. Only 2 outcomes:
1) Engine works
2) Engine fails

Probability of 1 is: 999,999/1,000,000 = 99.9999% - have a good day
Probability of 2 is: 1/1,000,000 = 0.001% - fly it all the way to the crash site

So we should all be flying twins..... Preferably push-pull reciprocals.

Okay, ready, aim, fire!

Right - I missed that. But it's an impossibility. If I could have a Ferrari with the economy of Geo - of course I would be one Magnum PI sumbitch mustache and all.

A1Skinner wrote:Read again and he states based on the same operating cost...

f you could have a 2-place, ~200 hp (total), twin experimental that would perform as well as a single with the same operating costs and identical build price, would you prefer it when flying in the backcountry? For sure!!

And assume: IFR capable, high performance, turbo-normalized, with a high single-engine service ceiling.

In other words, does the fact that it's a twin turn you off because of the extra flying requirements, or does the added safety of the extra engine in the backcountry make up for the complexity?

And assume: IFR capable, high performance, turbo-normalized, with a high single-engine service ceiling.

Is there one available

Sounds good to me!
I'll get the kit ASAP.
Let me know the brand?

It could be cool if you were the type to routinely practice single engine work.

You might be able to stay flying single engine but lose an engine on rotation and not be proficient in engine out emergencies and you're likely to be upside down in a grass field very quick.

Its very hard to replicate losing an engine right at rotation practicing in the airplane.

A simulator event practicing true engine loss on the critical engine at rotation is the best way to show the effects and not many private pilots have access or the option to get this kind of training.

Also just because you have a high single engine service ceiling doesn't mean you are going to clear those 50 foot evergreens off the end of the runway single engine.

Once out of the trees though, it is a very nice feeling having the extra insurance of a second engine.

I guess I'm not convinced that there is extra safety in a light twin.

Don't they have a worse fatal accident record than single engine planes?

And i agree with the above odds of losing both engines. I just ment you doubled your chances of having an engine failure (single engine failure) per hour flown

What's the saying about light twins "the second engine has just enough power to get you to the scene of the crash"

M6RV6 wrote:

f you could have a 2-place, ~200 hp (total), twin experimental that would perform as well as a single with the same operating costs and identical build price, would you prefer it when flying in the backcountry? For sure!!

And assume: IFR capable, high performance, turbo-normalized, with a high single-engine service ceiling.

In other words, does the fact that it's a twin turn you off because of the extra flying requirements, or does the added safety of the extra engine in the backcountry make up for the complexity?

And assume: IFR capable, high performance, turbo-normalized, with a high single-engine service ceiling.

Is there one available

Sounds good to me!
I'll get the kit ASAP.
Let me know the brand?

Not a kit, but there is one available. Check out the Tecnam twin. Only problem is it's $500K + for a 140 kt. airplane.

sigmatero wrote:If you could have a 2-place, ~200 hp (total), twin experimental that would perform as well as a single with the same operating costs and identical build price, would you prefer it when flying in the backcountry?

And assume: IFR capable, high performance, turbo-normalized, with a high single-engine service ceiling.

In other words, does the fact that it's a twin turn you off because of the extra flying requirements, or does the added safety of the extra engine in the backcountry make up for the complexity?

If such a thing were possible, it might be worth considering.
But really small twins don't make sense for backcountry.

In such a design, you would have to rely on both engines working to fly at normal weights in a backcountry environment (assuming realistic engine power to weight ratio).

The increased complexity creates more ways things can fail, as demonstrated probabilistically above. I work on this kind of stuff for a job, simpler really is better.

So maybe someone can come come up with a real baby Islander??
Good back country aircraft, high wing, and going from 10 place to 2 maybe would work with 200 instead of 500 HP
Don't know that the Tecnam would work in the Back Country very well, but a heck of a bird!! And there is that 500k tag on it!
GT

Probably not true backcountry (bushwheels won't fit in the wheelwells) but the Tecnam does fine on grass.

I remember seeing a twin engine Champ once - think they called it a "Lancer."

sigmatero wrote: If you could have a 2-place, ~200 hp (total), twin experimental that would perform as well as a single with the same operating costs and identical build price, would you prefer it when flying in the backcountry?......

With regards to backcountry ops, is a 100hp-per-side twin safer than a 200hp single, or even as safe? In the event of an engine failure, what's the climb rate gonna be on that single 100hp engine? Will it even be able to maintain level flight? And how many 100hp engines have feathering props to cut drag on the dead side?
I vote no.

Maybe some one can park a Tecnam and an Air Cam together in a dark Hangar and see what develops !
GT

Operating costs the same? On a Tecnam?

What do you do with those Rotax engines when they hit TBO?

You can overhaul a Lycoming.

Now, an economical small turbine.....

I know, an oxymoron.

MTV

A cheap to operate twin is about as rare as a loving affectionate wife who wants you to have "relationships" with her friends and sisters....

lc

mtv wrote:
What do you do with those Rotax engines when they hit TBO?

You overhaul it if you want or fly it past TBO - same as a lycoming/continental. I have no first hand experience I admit - but googling yields $10-12k rebuilds - seems inline with similar sized certificated engines or even a little less. I know people who buy runout over TBO rotax's happily - and lots of people are upgrading choosing to buy a brand new 18k 912 versus a 10k overhaul. Or upgrading to the new FI, or turbo 914.

Blu - odds of engine failure are purely independent. It is a mathematical impossibility to double the odds of failure with a second engine. Now the non-redundant bits and the common points of failure is another story - hence the second impossibility of it ever being "cheaper" maintenance and design costs of a twin. It's like saying you double your odds of rolling a 1 if you are throwing 2 dice as opposed to 1. The probability of rolling a 1 on a single die is ALWAYS the same. Within some generally accepted engineering principles - the probability of an engine failure is the same. This should not make you feel any better - but it is technically true.

A 200hp total twin will always be significantly heavier than a 200hp single. So performance will suck unless you play the displacement game to compensate. Cost will suck unless you trade safety - which you won't do.

This is a fun game - but it's a lot like the airplane on the conveyor belt viral internet discussion. I call it mental masturbation.