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?

[Dana]

The problem with JATO bottles...

You took me seriously...

 

[Half Fast]

You took me seriously...

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

 

[flyingron]

JATO bottles! Rocket up to 15,000 feet and your 10 minutes is glide time.

Good luck getting the STC...

If you hadn't realized it, my picture of the Ercoupe is a zero-takeoff role JATO launch.

 

[2-Bit Speed]

If you hadn't realized it, my picture of the Ercoupe is a zero-takeoff role JATO launch.

Was it re-usable afterwards? The Ercoupe, not the rockets...

 

[flyingron]

Yes, this took place at March Field as part of an AF-sponsored test run by CalTech. The aircraft had larger rudders installed on it. It did survive, but they decided to decommision it after the testing was over.

 

[Llewtrah381]

but they decided to decommision it after the testing was over.

Was it one of Space-X’s Unscheduled Rapid Decommissionings?

 

[SoonerAviator]

Was it one of Space-X’s Unscheduled Rapid Decommissionings?

I believe the PC-version was Rapid Coming From Together. Or was that the 6PC version? I foget.

 

[Initial Fix]

10 minutes? Pull the chute if you have it. Otherwise buy a twin (ok bring on That debate )

 

[DJTorrente]

It will fly a 1000-lb plane at 210 kts, in this application it needs to keep you in the air at 80kts or so. That's a lot less drag to overcome.
I see about 9gph at 75% power, but I can keep it airborne at bucket speed for about half the fuel flow.

Form (friction) drag is lower by the speed difference squared.
Induced drag is proportional to the square of the lift, but inverse to the square of the speed.

All else being equal, if the airframe/powerplant combination can lift 1000 lbs while moving at 210 kts, the same combination lifting 3x the load (3000 lbs. v. 1000 lbs.) at the same airspeed produces 9x greater induced drag. If you can generate that greater lift at 1/3 the airspeed, what was 210 now at 70, its a wash on the induced drag side of the equation while you capture the savings on the parasitic drag side. But that's usually not the way these things work.

In God We Trust; All Others Bring Data.

 

[2-Bit Speed]

Yes, this took place at March Field as part of an AF-sponsored test run by CalTech. The aircraft had larger rudders installed on it. It did survive, but they decided to decommision it after the testing was over.

Sounds like a minor alteration to me!!

 

[wanttaja]

You took me seriously...

Always. After all, you fly an Experimental. If I can have an ejection seat in my Fly Baby, why can't you have JATO on your Hatz?



Ron Wanttaja

 

[AV8R_87]

Man, some of you would've done a fine job in 1928 berating Frank Whittle for his stupid idea of proposing an airplane that could fly without a propeller. The British Air Ministry would've been so proud of you.
Same thing about BRS - while it seems like the forum is somewhat accepting them now, I can only imagine the derision if someone would have posted that as a topic here 25 years ago.

Good, fast and cheap - pick two of them. Seems like we're here today. 70k for that engine, plus installation and certification costs won't gain any customers, I agree. If someone figures out how to lower those costs maybe more people would consider it. How low before there might be any interest, well, that's what this conversation was meant to be about.

I'll leave this picture here. This time, it was people that most likely none of you knew. Next time, it might be someone you know and care about. Your son/daughter, and/or their kids. Don't ridicule someone who asks questions in the hope that one day such tragedies might be averted.

 

[Salty]

Man, some of you would've done a fine job in 1928 berating Frank Whittle for his stupid idea of proposing an airplane that could fly without a propeller. The British Air Ministry would've been so proud of you.
Same thing about BRS - while it seems like the forum is somewhat accepting them now, I can only imagine the derision if someone would have posted that as a topic here 25 years ago.

Good, fast and cheap - pick two of them. Seems like we're here today. 70k for that engine, plus installation and certification costs won't gain any customers, I agree. If someone figures out how to lower those costs maybe more people would consider it. How low before there might be any interest, well, that's what this conversation was meant to be about.

I'll leave this picture here. This time, it was people that most likely none of you knew. Next time, it might be someone you know and care about. Your son/daughter, and/or their kids. Don't ridicule someone who asks questions in the hope that one day such tragedies might be averted.
View attachment 126391

What is your motivation? Why does it matter what we think of your idea? Do you think anyone will change their minds if you use someone’s picture to make your dramatic point? Do you think the laws of physics will change if we all feel bad?

 

[ElPaso Pilot]

Man, some of you would've done a fine job in 1928 berating Frank Whittle for his stupid idea of proposing an airplane that could fly without a propeller. The British Air Ministry would've been so proud of you.
Same thing about BRS - while it seems like the forum is somewhat accepting them now, I can only imagine the derision if someone would have posted that as a topic here 25 years ago.

Good, fast and cheap - pick two of them. Seems like we're here today. 70k for that engine, plus installation and certification costs won't gain any customers, I agree. If someone figures out how to lower those costs maybe more people would consider it. How low before there might be any interest, well, that's what this conversation was meant to be about.

I'll leave this picture here. This time, it was people that most likely none of you knew. Next time, it might be someone you know and care about. Your son/daughter, and/or their kids. Don't ridicule someone who asks questions in the hope that one day such tragedies might be averted.

I think maybe you're using the wrong venue for this discussion.

Or you don't understand how an open web forum works.

You had some well thought responses addressing the restrictions YOU put on the discussion with simple data and straight physics.

 

[wanttaja]

Man, some of you would've done a fine job in 1928 berating Frank Whittle for his stupid idea of proposing an airplane that could fly without a propeller. The British Air Ministry would've been so proud of you.

Frank Whittle developed his engine over decades, with well-identified advantages if he succeeded.

Yet, you haven't offered any data on saving the number of lives if your system gets implemented.

Let's look at the Cessna 172 accident record. It's probably the most-common GA aircraft in the US.

Between 1998 and 2021, Cessna 172s suffered about 3200 accidents in the US. In eighty-five percent of them, your gadget wouldn't have made a difference. Only 15% of the accidents involved a loss of engine power... the only time where your whizbang could have made a difference. Could. That's important. Having backup propulsion doesn't ensure that an accident doesn't occur, just like having a CAPS doesn't exclude one from a fatal Cirrus accident.

Let's look further at that Cessna accident record. About 380 of those 3200 accidents resulted in at least one fatality. Only eight percent of those accidents involved the loss of engine power. That's about 30 accidents. They resulted in 40 people being killed.

Forty people. In twenty-four years. Your gadget, IF it had been universally installed in the most popular GA aircraft, and IF it had a 100% success rate...would have saved fewer than two lives per year.

Sure, you can scream, "Think of the children!" and claim that those two lives were worth whatever cost the aviation community would have to pay. But then again, you aren't paying it, are you?

Same thing about BRS - while it seems like the forum is somewhat accepting them now, I can only imagine the derision if someone would have posted that as a topic here 25 years ago.

Pul-eeeze. BRSs have been around much longer than the 25 years you claim. They've been discussed since the '80s. What Cirrus did was adapt proven ultralight technology to a production-class airplane.

And not everyone is against them. If you did any sort of research here, you'd see the discussions, and note that opinions are mixed...at least compared to the derision your proposal set off.

And yes, I'm one of the people who have supported the CAPS. Not because I own BRS stock, not because I like things that go boom, but because I did an accident analysis and liked what I saw.

Ron Wanttaja

 

[ElPaso Pilot]

I think maybe you're using the wrong venue for this discussion.

Or you don't understand how an open web forum works.

You had some well thought responses addressing the restrictions YOU put on the discussion with simple data and straight physics.

Answering my own question.

OP has only on been the forum for a month, with >100 posts since last Friday.

Sometimes people just need to step away from the keyboard for awhile and breathe the outside air.

 

[AV8R_87]

What is your motivation? Why does it matter what we think of your idea? Do you think anyone will change their minds if you use someone’s picture to make your dramatic point? Do you think the laws of physics will change if we all feel bad?

May I remind you what one of the goals of the forums is: encourage discussion, interest and education in all things aviation.
It's the dismissive mindset that bothers me, the "I don't understand it, therefore it must be useless" mentality. People that had no real understanding of the power required to keep their aircraft airborne, yet telling me to go take a physics 101 class.
My motivation, believe it or not, is aviation safety. This doesn't happen by accepting the status quo. Sometimes tough questions have to be asked, and answers might not be readily available. A healthy and constructive conversation might provide a path to a viable answer, which might be completely different than what the original question was expecting.
At the end of the day, I'd really like to see less of those mishaps happening, without making aviation unaffordable for the vast majority of people that can afford it today. If anything, I'd like to make it more affordable, but that's a conversation for another time.

I think maybe you're using the wrong venue for this discussion.

You might be right on this one.

You had some well thought responses addressing the restrictions YOU put on the discussion with simple data and straight physics.

True. I have no problem with that. I'm perfectly happy to discuss things based on actual facts.

Sometimes people just need to step away from the keyboard for awhile and breathe the air outside.

It's cold and miserable outside. Give it a few more weeks, they I'll see myself out.
(or maybe I'm in the hospital recovering from surgery - who remembers that?)

Let's look further at that Cessna accident record. About 380 of those 3200 accidents resulted in at least one fatality. Only eight percent of those accidents involved the loss of engine power. That's about 30 accidents. They resulted in 40 people being killed.

Forty people. In twenty-four years. Your gadget, IF it had been universally installed in the most popular GA aircraft, and IF it had a 100% success rate...would have saved fewer than two lives per year.

This is the kind of conversation I like to have. Even if the conclusion ends up not supporting my approach. Thank you.
Most people don't need their insurance policies, yet they still get them, even if not required (talking outside aviation as well). The idea was not to have it installed on every aircraft, but what if you had an option to install it later. So, user's choice. As I stated above, my goal is to make aviation safer and still affordable.

And yes, I'm one of the people who have supported the CAPS. Not because I own BRS stock, not because I like things that go boom, but because I did an accident analysis and liked what I saw.

Would you be willing to summarize what you liked? I'm also a fan of parachute systems, but (especially as retrofits) they seem difficult to install. When I was considering a certain model of experimental build (that will remain unnamed for now), one of the questions I asked them was "Will you assist me in installing one in it?". Their answer was a straight no, you're not allowed to deviate from the plans and we won't give you any information. Same line from others out there, too. "It's a strong airframe, you don't need a parachute for it" was the other answer. Only one was willing to work with me. Also, once you go over 1300lbs, BRS choices become a lot more limited. Can you blame me for looking at alternatives?

 

[MountainDude]

None of the options. BRS is the best solution (even better than a twin) and it already exists.

 

[2-Bit Speed]

None of the options. BRS is the best solution (even better than a twin) and it already exists.

Not to contradict, because I think CAPs is a good idea that gives more pilots more options, but it's not very useful during a Loss-of-Power on takeoff. That's the one singular application I have seen here that might a benefit from auxiliary propulsive power. But even that application would require significant training, design, and work to make such a system safe. Something like JATO (if I put aside my jokes for a moment) could, if improperly mated to an airframe, could cause significant damage and might upset the attitude of the plane during a critical phase of flight. That's not something an untrained (untrained for this specific concept, I don't mean an unlicensed pilot with zero PPL or LSA ticket) or poorly trained pilot is likely to survive. Any system designed to hook into the prop to keep IT spinning would need training similar to that required for flying a twin because the process would unlikely be easier. That means that this system is a twin without the benefit of a twin's extra power and altitude capability for most of its airtime.

 

[SoonerAviator]

Man, some of you would've done a fine job in 1928 berating Frank Whittle for his stupid idea of proposing an airplane that could fly without a propeller. The British Air Ministry would've been so proud of you.
Same thing about BRS - while it seems like the forum is somewhat accepting them now, I can only imagine the derision if someone would have posted that as a topic here 25 years ago.

Good, fast and cheap - pick two of them. Seems like we're here today. 70k for that engine, plus installation and certification costs won't gain any customers, I agree. If someone figures out how to lower those costs maybe more people would consider it. How low before there might be any interest, well, that's what this conversation was meant to be about.

I'll leave this picture here. This time, it was people that most likely none of you knew. Next time, it might be someone you know and care about. Your son/daughter, and/or their kids. Don't ridicule someone who asks questions in the hope that one day such tragedies might be averted.

There were some who were against BRS on principle, but they were in the minority. Most of the people who were against BRS (on existing airframes) said the cost/benefit wasn't worth it, in terms of lost payload, initial cost, and recurring maintenance/repacks. On something like the Cirrus, it was already in the design, so not much argument to be had there. There will always be dissention, but sometimes solutions are proposed to very rare problems . . . and those solutions present a large set of other problems/costs with them. Your solution falls into that category. Outright engine failures (not fuel exhaustion related) don't occur that often, when they do, they usually (per the data) don't result in fatalities. An engine failure at cruising altitude doesn't cause me a ton of anxiety, an engine failure just after takeoff does, but unless I could "cut over" to the auxiliary power within seconds, it doesn't help that scenario much. The enormous expense, additional systems complexity, and ongoing maintenance of ANY available option just doesn't pencil-out for most everyone. While "just get a twin" is a bit of a curt response, it's honestly what I'd recommend to someone who had a fear of losing an engine. It isn't any less complex than any JATO/battery-drive coupling/etc that has been proposed so far in this thread. It does carry the distinction of being cheaper than any of those proposed options and has been proven for a century. We're not required to be excited about your search for a solution, but we are probably a healthy sample of what responses you'd see from the larger aviation community.

 

[Dan Thomas]

This with its own fuel supply would weigh less than 150lbs and give you 10 mins or more. And plumbing it in the aircraft's fuel supply would give you more. Cost is where it's not going to work.

A turbine needs time to start and spool up. Since many engine failures occur shortly after takeoff, this thing will not help. Might actually make things worse as the pilot frantically tries to get it going instead of flyinmg the airplane.

The BRS 'chutes are also useless at low altitudes.

Look at the thrust on that. Ain't gonna cut it for a 3000+lb airplane.

Go try to fly your plane at 35% power. Hint (Economy cruise is your most efficient, any deviations from that and you get less efficient)

And then immediately after that sign up for physics 101.

That there.

 

[Maxnr]

View attachment 126357

Right on Ron! If I recall correctly, this was a Navy project conducted mid WW2. Burn time was in seconds. Ever seen a Fat Albert RATO t.o.? (Fat Albert had access to the world wide supply of RATOs until exhausted. About 2 years) The unit on the Ercoupe's belly was about the size and weight of a wall mounted fire extinguisher.
Now, if the burn rate on the RATO unit were slowed to last a minute or more and a second one was mounted, you would have something that was useful.
I would dread to have to fly a MAP in IMC.

 

[3393RP]

View attachment 126373

Plumbing one of these in would solve the 10-minute problem for a good number of engine failures in flight. Might need two for a twin, to get 10 minutes, depending on the engines.

I have one of those cans. The plane would crash while trying to get the damned thing to release the fuel.

 

[Mikey52]

We had jato bottles on a Howard 350 I flew, they were required to meet performance requirements to get to the second segment climb performance at gross weight. They would fire automatically with loss of an engine after becoming airborne. Luckily never needed them.

 

[SebIp]

Isn’t caps usable by 500 feet? And they say you should use it anyways if lower?

I think really caps is about the most sensible backup for single engine lost of power. You can try this or that but a device that lets you come back down without dying passively is about as useful as you can get. You can even tell your passengers to slow down if you are disabled and pull the handle.

I wish I have caps would make the wife a lot less nervous.

 

[Bob Noel]

Since nothing is 100% safe, the question is what is safe enough?

 

[Half Fast]

You can even tell your passengers to slow down if you are disabled and pull the handle.

Yep. CAPS and autoland are the only things I’ve seen that can account for pilot incapacitation. The proposed auxiliary jet engine, even if feasible, would require more pilot skill during a high-stress event. A push-button save has a greater likelihood of success.

 

[SebIp]

Since nothing is 100% safe, the question is what is safe enough?

Death. Once you are dead everything is safe.

Bad jokes aside. Don’t we all mentally make that decision the risk is acceptable when we push the throttle forward for take off?

 

[PaulS]

Isn’t caps usable by 500 feet? And they say you should use it anyways if lower?

I think really caps is about the most sensible backup for single engine lost of power. You can try this or that but a device that lets you come back down without dying passively is about as useful as you can get. You can even tell your passengers to slow down if you are disabled and pull the handle.

I wish I have caps would make the wife a lot less nervous.

Yup, I had an instructor who survived a low caps actuation unscathed. He was checking out in a Cirrus with an instructor, engine stopped producing power. The thought they had the field made, on the glide in they realized it wasn't going to end well, they weren't going to make the field, so they pulled at about 320 feet. The recommended minimum for that model was 500 feet. They landed in a swamp and walked away. Cirrus recommends landing straight ahead if the engine goes on take off, but if it looks hopeless, pull.

CAPS, more specifically a ballistic chute, is a good idea that is now proven to be a lifesaver. There is a weight penalty and a maintenance cost, but the upside far exceeds the downsides. CAPS saves pilots from many situations beyond just power loss, which is important when considering whether an idea is worthy of consideration.

Let's face it, a back up propulsion system for a single is not a very good idea because it only addresses a narrow slice of issues that take out pilots. The penalty in weight and maintenance would not be worth it.

 

[bflynn]

To be clear, he's talking about strapping a mini jet engine to the plane.

Not useful.

An electric motor with a small battery might be a better choice. For about 200 lbs of useful load, you could get 10 minutes of flight time, which at a minimum allows you to pick your off airport landing spot. The math might be based on old battery tech and if you slow to best range speed, the battery could last longer / be smaller so maybe actual numbers are better.

The problem here is that some airplanes can't afford to lose 200 lbs of useful load.

 

[Ashara Keliyn]

Didn't do the math, but what about flywheels? You're again sacrificing weight, however it's a simpler system with lower maintenance requirements.

 

[Salty]

Didn't do the math, but what about flywheels? You're again sacrificing weight, however it's a simpler system with lower maintenance requirements.

How about big rubber bands?

 

[Ashara Keliyn]

How about big runner bands?

Or bunch of RC airplane engines (gas) in a pusher configuration

 

[wanttaja]

Didn't do the math, but what about flywheels? You're again sacrificing weight, however it's a simpler system with lower maintenance requirements.

Would require a clutch/transmission to send the flywheel energy to the propeller. One more failure mode.

To be useful, too, that flywheel would have to be spun up at operating speed for the entire duration of the flight. The precession alone would probably take a pretty complex set of flight tests to determine the effect on aircraft flight characteristics and develop mitigation. Plus, when the flywheel is in use (in an emergency situation), the gyroscopic effect will be changing through the entire event. Something ELSE the pilot has to be aware of....

Ron Wanttaja

 

[wanttaja]

How about big runner bands?

Here ya go...it's patented, even.

Rubber band is connected to the wheels, and the rubber band is wound during each landing rollout.

Ron Wanttaja

 

[frfly172]

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

 

[Ed Haywood]

Here ya go...it's patented, even.
View attachment 126475
Rubber band is connected to the wheels, and the rubber band is wound during each landing rollout.

Ron Wanttaja

Only thing missing from that diagram is a coyote and an anvil.

 

[Half Fast]

Only thing missing from that diagram is a coyote and an anvil.

And Rube Goldberg's signature on the drawing.

 

[asicer]

what about flywheels?

The gyroscopic side-effects sound like a lot of fun in an airplane.

 

[Half Fast]

Would require a clutch/transmission to send the flywheel energy to the propeller. One more failure mode.

To be useful, too, that flywheel would have to be spun up at operating speed for the entire duration of the flight. The precession alone would probably take a pretty complex set of flight tests to determine the effect on aircraft flight characteristics and develop mitigation. Plus, when the flywheel is in use (in an emergency situation), the gyroscopic effect will be changing through the entire event. Something ELSE the pilot has to be aware of....

Ron Wanttaja

Might be able to mitigate the precession with two counter-rotating flywheels. Have a coil on one and a magnet on the other, both sides with the same moment of inertia. Drive it like a motor to spin the masses up to speed, or geared off the engine with a clutch, then cut it in as a generator to make electrical power for a motor and it will spin down. BUT, the power needed, the rotational mass, and the rotational speed would be enormous, and any sort of failure catastrophic.

Overall it would have a worse failure mode and a higher probablility of failure than the problem it seeks to solve.