Would you be interested in some form of back-up propulsion for your piston single? If yes, how much would you be willing to pay for it?

[Tarheelpilot]

I thought we were all pretending this to be a serious thread.

Well if we are not then we have a real opportunity to learn about each other in this thread.

 

[MooneyDriver78]

So just go out and buy a 336/337 and only use one engine untill you need the backup engine

In my experience, complicated mechanical systems like engines need to be used to insure they work when needed.
A backup system better be simple and reliable when sitting for long periods of time.

 

[Ed Haywood]

Since no magic device exists, and CAPS cannot be retrofit to the great majority of GA legacy airframes, we are stuck with:

A) spend more money on maintenance.
B) spend more money on training.
C) spend more money on modernization and safety- enhancing devices.

All of those things exist and are readily available.

 

[Maxnr]

Time to bring back the trimotors?

 

[Dan Thomas]

Since no magic device exists, and CAPS cannot be retrofit to the great majority of GA legacy airframes, we are stuck with:

A) spend more money on maintenance.
B) spend more money on training.
C) spend more money on modernization and safety- enhancing devices.

All of those things exist and are readily available.

The typical owner responses are:

A) If it ain't broke, don't fix it.
B) I'm a good pilot. Don't need no more training.
C) My old airplane with its old stuff works just fine. Why do I need shoulder harnesses anyway? Or a new fire extinguisher? Or a 60-amp alternator instead of my ancient 30-amp generator that doesn't even generate under 1200 RPM? Or a decent Com so that everyone else can understand me, and I can hear them? Or an ELT that works?

 

[francisco collazos]

100's of helium balloons would be better. don't have to feed them and they pack tight until inflation.

ok two possibilites ...

one ... get those size D estes rockets and attach enough of them to get you a better glide aka....Wile E Coyote
two ... instead of filling balloons just bring the helium tank and put it in the plane. This should keep it floating.

 

[Checkout_my_Six]

backup power....like extra engines? otherwise you clearly don't understand how planes are designed.

 

[MRC01]

My backup propulsion is gravity, aka converting potential energy to kinetic energy, aka gliding.
A single engine airplane has less chance of engine failure than a twin, and when an engine fails, the airplane is easier to control.
That said, as others have said here, properly maintaining and operating the engine greatly reduces the chance of failure.

 

[SoonerAviator]

ok two possibilites ...

one ... get those size D estes rockets and attach enough of them to get you a better glide aka....Wile E Coyote
two ... instead of filling balloons just bring the helium tank and put it in the plane. This should keep it floating.

I always had trouble getting them to ignite with the battery-powered launch control. My father's battery charger never failed to light them off though!

 

[The Master]

No one is really taking this seriously.
A Cessna 150 at the optimum speed can maintain altitude on 25 hp.
Now imagine a high strung two stroke 'power pod' than swings up from the empennage, like one of those power modules on a sailplane, with a 2 ft dia. prop.
I imagine the whole system could be done in 50 lbs.
Would use same airplane fuel supply, and have its own oiler.
Every six months you would test it on the ground, just like a residential emergency generator.
Hp requirements might surprise you. Remember, all we want to do is maintain altitude when lose an engine, not climb. Or even just greatly extend a glide.
Not saying the idea is wise, but a lot of you are dismissive about the engineering

 

[Salty]

No one is really taking this seriously.
A Cessna 150 at the optimum speed can maintain altitude on 25 hp.
Now imagine a high strung two stroke 'power pod' than swings up from the empennage, like one of those power modules on a sailplane, with a 2 ft dia. prop.
I imagine the whole system could be done in 50 lbs.
Would use same airplane fuel supply, and have its own oiler.
Every six months you would test it on the ground, just like a residential emergency generator.
Hp requirements might surprise you. Remember, all we want to do is maintain altitude when lose an engine, not climb. Or even just greatly extend a glide.
Not saying the idea is wise, but a lot of you are dismissive about the engineering

you aren’t reading the posts.

his engine doesn’t run on the same fuel. In fact, either engine would stop running if fueled with the other engines fuel.
you aren't building a ”power pod” as you describe in 50 pounds.
retrofitting a pod like this is going to be costly, chew up useful load and worse, take up a lot of space.

 

[AV8R_87]

his engine doesn’t run on the same fuel.

"My engine" was just an example of something that could generate the required thrust for the required weight, to silence the "physics don't work for this" crowd. The actual powerplant could be something completely different.

Even if a turbine engine was used, they can run on leaded gasoline. Not for 1000 hours, since the lead deposits will have an impact on overall life. But in this application, longevity is not a design goal.
The time limit has more to do with the installation and certification effort required to use the existing fuel supply. Might be easier, cheaper and lighter to have a dedicated fuel tank, even if the fuel is the same. Hence the time limit.

retrofitting a pod like this

This is a valid point. While it would be "relatively" straightforward to implement in a new airframe build, the retrofit would be almost as difficult as installing a BRS.

On the topic of BRS installs, while they could cover some additional use cases, they overall get used for engine failures. The same argument made over how many fatalities were caused by engine failures can also be applied to BRS installs, yet (even in this topic) the attitude towards them is slightly different now. You're still hauling a load of expensive equipment with non-trivial overhaul costs for the remote possibility of a mishap that would require you to use it.
A BRS retrofit for a 172/182 was in the range of 20k (and I think that was parts only) last time I looked, a couple years ago. Haven't heard of too many takers. The RV-10 has a BRS option now, it's 30k in parts plus labor to install. Haven't seen one with it in the wild yet.
And a BRS retrofit without manufacturer support is very difficult, if not impossible. The failure modes of an improperly attached BRS will result in fatalities when you deploy it, with very little chance of recovery. From my own experience while reaching out to experimental kit makers, a lot of them would not talk to you at all about a retrofit.

Ron Wanttanja made a good point that (at the Cessna level) this would only save two lives a year. The overall number of powerplant failure fatalities per year is about 20-25, out of 200-230 total fatalities per year. That's 10(-ish)% of all GA fatalities.
https://www.ntsb.gov/safety/data/Pages/GeneralAviationDashboard.aspx - great tool for quick data look-up.

I don't think that includes the ones where they couldn't find anything wrong with the engine after the crash, despite it being reported as stopped before. Remove some of those accidents, as they might be in airframes that nobody will attempt to certify such a mod to, due to low production numbers and not enough of them still flying. That might leave you with 10-15 fatalities a year that might be averted. Probably a few off-airport landings with serious injuries and airframes being written off would also not happen. And I think that's also worth considering, too. A broken back that can be avoided might be worth the safety investment.

Depending on how you want to phrase it, you can either be honest and say that it might reduce the total number of GA fatalities by 5% (which isn't a number to be ignored) or that it will reduce the number of engine failure fatalities by 50% (but I agree that it might be a bit dishonest to phrase it this way). And it would be a personal choice to install this in your airframe, if available. Nobody would force you to do it.

Speaking of personal choice...
We don't need to put in fancy electronic attitude indicators (primary or back-up). Our planes have been certified and proven to be IFR-capable with two iron gyros spun by a brittle graphite-vaned vacuum pump, and an electric turn coordinator. Yet a lot of us chose to install thousands of dollars worth of additional equipment just for the extra safety. I'm not even talking about full glass cockpits, just the G-5, GI-275, AV-30 or similar group. Shoulder harnesses are only useful for a handful of scenarios, yet I don't think anyone here would argue against them.

One important point, and I'm sure you've all heard this one before - Statistics are meaningless until you become one.

Greatest loss of life in GA happens because of loss of control accidents - yet how many pilots practice slow flight and stalls after they get their certificates? A lot of them might do it every two years at their flight reviews (if that). How many people do you know that go out and practice slow flight, stalls and similar things regularly? That might be the topic of another thread/poll.
We (as a group) definitely seem to be thinking bad things only happen to other people.

won't say that it's impossible. What I will say is that it seems to be very complex to design, consumes useful space, will be more expensive than you think (just like everything else on a plane) and will add significant maintenance cost. Is it worth the trade-off vs. CAPS or equivalent? Hmmm.....

This is the kind of conversation worth having. It's definitely not an easy task. If someone was willing to pay 300k today, it might happen. Take that 70k jet engine, add 30k in install costs and 200k in certification costs. Any takers? 99.999999% convinced the answer would be no for a 75-100k airframe.
Hence why the question was asked the way it was asked. It wasn't a case of "do you think this is possible?", but "how much would you pay for it?". Give me enough money and I'll make a washing machine achieve controlled flight. Isn't that how helicopters fly?

Thank you to all that answered the poll. If those are truthful answers, it's actually better than I thought it would be, but the sample size is a bit small.

 

[DJTorrente]

"My engine" was just an example of something that could generate the required thrust for the required weight, to silence the "physics don't work for this" crowd. The actual powerplant could be something completely different.

Don't take it all so personally. Besides, the beauty of a capitalist economy is that if you're right and everyone else is wrong, then you stand to be in a better position to become fabulously wealthy due to the information imbalance. I'm sure the Klapmeyer brothers profited handsomely from the sale of Cirrus in the face of the BRS nay-sayers you mention upthread. That Could Be You.

That said, since you're asking pilots' opinions on how they would spend their own dollars (even hypothetical ones), its not the least bit unreasonable for them to inquire about how you plan to make your blue-sky dreams a reality. Spare us the "YOU COULD BE THE NEXT STATISTIC!!!!" That pitch puts you on the level of a whole life insurance salesmen who trolls class reunions that aren't even his class. Pilots know the risks they are taking, and most take appropriate steps to manage those risks. Pledging six figure sums to unproven and seemingly indescribable magic carpet technology is not a successful risk management strategy.

 

[ElPaso Pilot]

Give me enough money and I'll make a washing machine achieve controlled flight.

Speaking of personal choice...

How much of your money (vs other people’s money) are you going to put forward to research, develop, test, and certify this noble cause?

You mention BRS retrofit solutions several times and that no one would speak to you.

Open your checkbook to fund the risk and cost, and they will design and certify an installation on your plane. Or even your washing machine.

 

[MRC01]

... Pilots know the risks they are taking, and most take appropriate steps to manage those risks. ...

Well said. And as we analyze the root causes of incidents, we realize how many are caused by improper planning, maintenance or operating procedures. This tells us how greatly we can improve safety with the airplanes we already have by learning best practices and following them.

Even proven safety devices like a chute are not as big a factor as some think they are. Many of the Cirrus "saves" would have turned out fine without the chute, or were saves from situations the pilot never would have entered but for the false sense of safety the chute provided. That is not to say the chute is worthless - there have been some genuine saves. My point is that assuming every chute pull is a "save" (as many people do) is misleading.

Not to pick on Cirrus, but another aspect of that airplane's history demonstrates that training, not extra doo-dads, is the most effective way to improve safety. At first, Cirrus had a poor safety record compared to the rest of GA. It turned out there was nothing wrong with the airplane, but the people flying them needed better training. Too often, these pilots had more money than experience, enabling them to upgrade to a complex, fast airplane like the Cirrus early in their flying experience, before gaining enough hours to develop the necessary judgment. Cirrus created a transition training program and campaign to get all Cirrus owners & pilots to take it. Over time this was successful and turned around their safety record. No changes to the airplane, just better training.

 

[Dan Thomas]

I don't think that includes the ones where they couldn't find anything wrong with the engine after the crash, despite it being reported as stopped before

The vast majority of such failures are due to carb ice, according to AOPA. The investigators can't definitely blame it on carb ice, since the ice is long gone when they get to the wreck, but they will state that "the conditions were conducive to carb icing at the time of the accident."

That makes it a training issue. I found that way too many PPLs AND instructors did not understand the physics of carb icing. They think it's winter problem, or an IMC problem. So they are not prepared to recognize and deal with it. It gets them.

 

[Dan Thomas]

No one is really taking this seriously.
A Cessna 150 at the optimum speed can maintain altitude on 25 hp.
Now imagine a high strung two stroke 'power pod' than swings up from the empennage, like one of those power modules on a sailplane, with a 2 ft dia. prop.
I imagine the whole system could be done in 50 lbs.
Would use same airplane fuel supply, and have its own oiler.
Every six months you would test it on the ground, just like a residential emergency generator.
Hp requirements might surprise you. Remember, all we want to do is maintain altitude when lose an engine, not climb. Or even just greatly extend a glide.
Not saying the idea is wise, but a lot of you are dismissive about the engineering

Are you a pilot? Do you have any idea what happens to weight and balance when you stick 50 pounds in the tail cone? Do you know what happens to a 150's useful load with another 50 pounds aboard?

And that's even if it could be at 50 pounds, which it cannot.

 

[Capngrog]

Eastern Airlines had three (as I recall) of these for use at some of the high altitude South American airports. They were supposed to only be used in the event of an engine failure on takeoff. I don't know if this capability was ever used, but on a hot day at high altitude ... my guess would be yes. Some passengers seated above these things may have needed an underwear change after they went off.

 

[AV8R_87]

That said, since you're asking pilots' opinions on how they would spend their own dollars (even hypothetical ones), its not the least bit unreasonable for them to inquire about how you plan to make your blue-sky dreams a reality.

It's one thing to be asked pertinent questions, but another to be called an idiot by people that didn't really know any better.

Spare us the "YOU COULD BE THE NEXT STATISTIC!!!!"

Sadly, that is the case. We can all become the next statistic, whether we like to admit it or not. Your engine (or mine, or anyone else's) can decide to grenade itself over hostile terrain and leave us with no exit strategy. Short of deciding you're only going to fly over perfectly flat states with no trees or other obstacles during day VFR conditions, you're always exposing yourself to a small (but non-zero) risk.

Pilots know the risks they are taking, and most take appropriate steps to manage those risks.

I will respectfully disagree with you on this one. We could discuss this further in a separate thread if you'd like to. We see enough accidents caused by lack of even the most basic pre-flights, and other similar things that would only take minutes to inspect and rectify. We're all supposed to know the risks of an engine out during takeoff, yet how many people don't bother sumping their tanks? All these loss of control accidents, but when I ask local pilots how often they go and practice slow flight, stalls and similar things the answer I get almost all the time is "never". Or a VFR-only pilot that only puts foggles on for his flight review. We become desensitized, but we don't manage the risks well. At least not at the GA level.

Speaking of personal choice...

How much of your money (vs other people’s money) are you going to put forward to research, develop, test, and certify this noble cause?

A decent amount. Most development ideas start with a preliminary design followed by a market survey (see poll). Nobody sinks a million+ dollars into something without trying to figure out first if he can recoup the development costs. Boeing didn't design the 777 in a vacuum. They reached out to potential customers to figure out what they wanted and what it would take for them to place orders before the design work started.

You mention BRS retrofit solutions several times and that no one would speak to you.

Open your checkbook to fund the risk and cost, and they will design and certify an installation on your plane.

I wasn't asking for free stuff. The one manufacturer who was willing to talk about it mentioned clearly that they had sufficient interest from potential builders to work on that. The others said things like "it's a safe and strong airframe, you don't need a parachute for it!". It wasn't a case of "not enough interest, so we're not sinking money into it". They just saw no need for it, period. While pushing some questionable engine choices and telling potential builders that they won't get any factory support (even for the airframe build) if they went with a different engine.

 

[The Master]

Are you a pilot? Do you have any idea what happens to weight and balance when you stick 50 pounds in the tail cone? Do you know what happens to a 150's useful load with another 50 pounds aboard?

And that's even if it could be at 50 pounds, which it cannot.

I am a PP and engineer. The Cessna was just given as an example of how surprisingly little HP might be required just to barely maintain altitude at that scale and drag . (I said 25 HP but it may actually be as low as 17 HP when I researched it back when) I never mentioned such a system could be added to an existing C150. If someone designed "the new Cessna 150 of the 21st century," they could then design in such a system. And they would prolly have an extra weight allowance to work with as well, being a more modern design with 912 upfront, etc etc.

Yes it could be done at 50 pounds, which it can.

P.S. I also calculated someone flying a handglider might maintain altitude with a .60 ci model airplane engine with around 2 hp

 

[ateamer]

Longer wings and winglets? Could potentially increase glide range and I don’t think it’d be expensive either. Thoughts?

That would kill the handling of an RV.

 

[ateamer]

you aren’t reading the posts.

his engine doesn’t run on the same fuel. In fact, either engine would stop running if fueled with the other engines fuel.
you aren't building a ”power pod” as you describe in 50 pounds.
retrofitting a pod like this is going to be costly, chew up useful load and worse, take up a lot of space.

And adding 50 pounds near the tail could have just a minor effect on weight and balance.i

 

[ateamer]

It’s cheaper to maintain the engine and systems, get recurrent training, and practice emergency procedures at least quarterly. One good way is to quit doing the FAA and 300 hour CFI-recommended power-on flat final from three counties away, and to mix it up with power-off (or rather idle power) precision 180s at lesst one out of every four landings. It’s fun, too, and the improved skill transfers to other areas.

 

[Dan Thomas]

I am a PP and engineer.

Then you should know this chart:



I was never able to keep a 150 aloft in endurance flight at anything less than 2000 RPM, around 38% power. 25% is just wishful thinking. The 150's POH cruise chart doesn't even list anything under 40%:



The 150 is notoriously underpowered. We had two in the flight school. I instructed in them and maintained them (I am also an Aircraft Maintenance Engineer). On hot days they were almost useless, even with freshly overhauled engines.

Go ahead. Add 50 pounds and 30 HP to a 150. It won't end well. A heavier airplane like a 172 or 182 would need much more power, meaning more weight. Our airplanes are already weight- and power-limited.

 

[CaptainXap]

Despite all the hate, I think this is quite a neat idea.

It would be cool to have something that could give you two minutes of power - just enough to get you back to the airport if you had an engine failure of takeoff. I like the idea of replacing something that's already there (the starter motor) with something more powerful that would allow your plane to limp home.

However - despite electric motors being a lot lighter than ICE engines, they're not *that* light. A 75KW motor still weighs a lot more than a starter motor, and a 3KWH battery is still pretty heavy. So maybe it could be done, but you're probably still talking 100lbs or so for 150 seconds of flight.

So it seems like a nice idea that just isn't practical with current tech. I think if it does become practical it would probably also mean that electric aviation would be practical, which would be awesome.

 

[Klaus M]

Here's an example of an alternative to an engine failure:


...And you can go fishing too

 

[Daleandee]

Here's an example of an alternative to an engine failure:
View attachment 126708

...And you can go fishing too

That's a great idea ... unless you're over the forest!

 

[Tantalum]

Twin. Or for those scared of VMC roll issues and proficiency, you have the Skymaster. You can pick up a Skymaster well below $200K.. but they seem to sit a long time. The same ones I was scrolling through months ago are still there. Oddly, people are spending well over $200K for singles. The market does not appear to want this.

You've also got (well had) the Rutan Defiant and the A500 for people terrified of asym thrust. Neither became a success.

 

[The Master]

Then you should know this chart:

View attachment 126699

I was never able to keep a 150 aloft in endurance flight at anything less than 2000 RPM, around 38% power. 25% is just wishful thinking. The 150's POH cruise chart doesn't even list anything under 40%:

View attachment 126700

The 150 is notoriously underpowered. We had two in the flight school. I instructed in them and maintained them (I am also an Aircraft Maintenance Engineer). On hot days they were almost useless, even with freshly overhauled engines.

Go ahead. Add 50 pounds and 30 HP to a 150. It won't end well. A heavier airplane like a 172 or 182 would need much more power, meaning more weight. Our airplanes are already weight- and power-limited.

The second chart isn't showing speeds anywhere near Vx, and yet still shows power levels as low as 40 hp, and at 82 knots!

I said the minimum power requirement to hold at altitude at best speed (Vx) in a typical small airplane (C150 in this case) is 25 hp.

And the first chart isn't even from the C150 POH, and is either missing context or isn't even for a C150. Nice one there.

I'm not saying someone should retrofit a system on a Cessna 150. I am saying the OP is right about his concept, as long as the concept is to barely maintain altitude at Vx speed (or even just to extend the glide). It could be done with 50 lbs addition to a new aircraft design.

 

[Dan Thomas]

Engine cost, maintenance and overhaul is probably the biggest part of the airplane's overall costs. Adding an engine adds a lot of cost, dead weight for 99.999% of the time, and it needs regular maintenance to keep it ready for an emergency. It needs to deploy and start, without fail, in a very few seconds. So, it's neither cheap nor easy.

Even the Cirrus 'chute has to be repacked every ten years. When I was working on one about 14 years ago, it was about $15K for the repack, IIRC. $1500 per year to maintain just that one item.

 

[PaulS]

Engine cost, maintenance and overhaul is probably the biggest part of the airplane's overall costs. Adding an engine adds a lot of cost, dead weight for 99.999% of the time, and it needs regular maintenance to keep it ready for an emergency. It needs to deploy and start, without fail, in a very few seconds. So, it's neither cheap nor easy.

Even the Cirrus 'chute has to be repacked every ten years. When I was working on one about 14 years ago, it was about $15K for the repack, IIRC. $1500 per year to maintain just that one item.

It's more now, and for some dumb reason the parts are hard to come by. Apparently the rocket motors begin degrading as soon as they are made, with 10 years being the time the manufacturer has determined they need to be replaced.

 

[Dan Thomas]

And the first chart isn't even from the C150 POH, and is either missing context or isn't even for a C150. Nice one there.

The 150 uses that engine. That chart shows the HP generated at various RPM when loaded with a propeller appropriate to the airplane. My experience is that endurance flight is near Vy, which is close to best L/D or best glide, and 2000 RPM is about the minimum to do that.

Have you flown a 150 in best range or best endurance situations, as well as slow flight? What is the procedure for determining best endurance power setting?

 

[Dan Thomas]

The second chart isn't showing speeds anywhere near Vx, and yet still shows power levels as low as 40 hp, and at 82 knots

Sure, and that's at 2200 RPM. it doesn't take much more RPM loss before you start sinking.

 

[Klaus M]

That's a great idea ... unless you're over the forest!

Just follow rivers and fly over lakes. Plus, there's no fish in the forest anyway

 

[PaulS]

What percentage of ga singles are 150s?

 

[pfarber]

How do you propose to keep my 3600lb plane aloft for 10 minutes with a weight of 150 lbs? This doesn't exist because of physics, not cost. There's already an expensive backup propulsion system available....it's called a twin.

Now, if a BRS were available for my plane, I'd be very interested.

BRS is available for EAB. The certified world is SOL pretty much.

my idea is for a rocket motor in the prop spinner so when you land you go from 70 to 0 in a few feet... but most engine mounts hate compression.

 

[Salty]

BRS is available for EAB. The certified world is SOL pretty much.

my idea is for a rocket motor in the prop spinner so when you land you go from 70 to 0 in a few feet... but most engine mounts hate compression.

Rapid deceleration is the problem, not the solution.

 

[Dan Thomas]

BRS is available for EAB. The certified world is SOL pretty much.

Oh really? They are available as STC'd installations for several certified aircraft models. Their website seems to be down right now so I can't get the Approved Models List.

 

[AV8R_87]

Off the top of my head I know they're available for the 172/182 on the certified side. 20k in parts, 80-90 lbs. Not aware of anything else with an FAA certification (besides Cirrus).

 

[DJTorrente]

Looks like PW Canada beat you to the market. Good luck with the GenAv market.