Adding redundant fuel and spark to auto/sled/motorcycle conversions.

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Vigilant1

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What sort of fellow would think it's ok to use aluminum for an aircraft exhaust system though?
Well, really, if the SDS requires users to have a special exhaust system, you should spell that out in the installation manual. "The impingement of exhaust gasses or flames onto the wires, sensors, injectors or the ECU unit itself will result in degraded operations of your EM-5 and voids the manufacturer's warranty."

Hey, the aluminum was lighter and easy to bend!

No fire? He was darn lucky. That's the nightmare I probably share with a lot of pilots--a fuel fire that I can't get extinguished. It would be a most bad way to sign off.
 

pictsidhe

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Modern plugs very rarely fail in modern engines. If one does, is being one pot down going to be game over? Coils fail far more often, though less so now.
Options: HV diodes from dual systems. That introduces diodes as a new failure point, though.
Separate coils for each plug. If you ran twin ignition and diodes, you'd be very unlikely to be more than onr pot down.

Condidering the reliability of proven modern car systems, I do wonder if you can improve on it with a redundant system without doing a lot of testing.

As Ross says, it's usually the wiring. My experience is that very few people can come close to car manufacturer reliable wiring.
 

rv6ejguy

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The same sort that lands in tomato fields rather than on runways.


BJC
Ah, there is more to the story. The builder wasn't flying it, Titan's chief pilot was carrying out a test flight for the builder.

Here's ur keys back son. Thanks for almost killing me! and I hope you don't mind I changed the color of ur plane a bit...
 

Vigilant1

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As Ross says, it's usually the wiring. My experience is that very few people can come close to car manufacturer reliable wiring.
Well, sometimes. But as the (ex)owner of a Triumph (the bad British Leyland years) and Jaguar (older than that), I can assure you there are exceptions. :)

Come to think of it, maybe this is the source of my apprehension regarding mission-critical electronics. Lucas and Smiths--uggh.
 

pictsidhe

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Ah, there is more to the story. The builder wasn't flying it, Titan's chief pilot was carrying out a test flight for the builder.

Here's ur keys back son. Thanks for almost killing me! and I hope you don't mind I changed the color of ur plane a bit...
That'll learn him to test a numpty's plane for him.
 

Himat

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If we are converting an engine that is already equipped with modern electronic ignition (EI) and electronic fuel injection (EFI) systems, what are the options for adding economical, lightweight, reliable redundancy for assuring fuel and spark continue to arrive? I understand and agree that these modern systems are highly reliable. Maybe from an objective standpoint redundancy isn't warranted (after all, there are plenty of other single points of failure on any engine: we don't have a redundant crankshaft, water pump, oil pump, throttle cable, etc). But if we nonetheless want redundancy in fuel and spark, what's the best way?

...

Opinions (and spears) are welcome and expected . . .
Option four:
  • Have dual ignitions systems that are two completely separate systems of different design and implementation.
  • Have a separate fuel injection system for each cylinder with the least possible common parts.
It will be awkward to have one fuel tank for the fuel injection for each cylinder. The run out of fuel due to faulty tank filling procedure do rise. This actually highlight the trouble with adding redundancy, fault modes are most often added too…
 

jbiplane

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We - www.aviamech.com have solution for complete reservation of Fuel injection and spark ignition for 1,2 and 4 cylinder engines.
Complete solution (instalation kit) is relativelly expensive 2100 USD (standard kit 800 USD)
Have as well batteryless option for our EMS.
 

Vigilant1

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We - www.aviamech.com have solution for complete reservation of Fuel injection and spark ignition for 1,2 and 4 cylinder engines.
Complete solution (instalation kit) is relativelly expensive 2100 USD (standard kit 800 USD)
Have as well batteryless option for our EMS.
Thank you for posting. I followed the link to your site, but there was no information about fuel injection or ignition systems. There were three products shown (15-28 HP engines), and it was not possible to see the specifications on those engines in English.
 

jbiplane

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Thank you for posting. I followed the link to your site, but there was no information about fuel injection or ignition systems. There were three products shown (15-28 HP engines), and it was not possible to see the specifications on those engines in English.
Yes, no time to make good site. Will do in few months. We make a better site for our umbrella company http://uav-siberia.com/en/ but may be not play with design and put more info by the simplest old way :) We have numerous docs which have to be translated soon.
 

dsigned

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A Titan T51 experienced the same sort of issue and forced landed in a tomato field. The owner had decided to make a set of aluminum (instead of the usual steel) exhaust stacks. Predictably, they melted and the hot gases melted the crank sensor wire through.

Subsequently, we provided the sensors with a 3 foot length of fire sleeve. We now provide Tefzel cabling plus firesleeve as this is a critical component.

What sort of fellow would think it's ok to use aluminum for an aircraft exhaust system though?
In fairness, GM has integrated the exhaust manifold on their latest V6 turbocharged engines into the head (aluminum). Presumably that's water-cooled though.
 

Topaz

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My objective is to be able to land safely in a way/place that poses only minimal chance of damage/injury. Say, 30-45 minutes of available flight time with the ability to safely climb at a moderate rate. I don't care if I don't reach my initial destination....
I won't speak to the electronics issues, because that's not my area of knowledge. I am going to freely admit that my viewpoint is biased by the kind of flying I've done. Hold that in your mind up-front.

BUT, if the quote above is genuinely your objective, none of that excepting the "available flight time" has anything to do with the engine or any of its systems. Safely landing "out" without an engine is just another skill to learn, like stalls or short-field takeoffs. Landing "out" is a matter of planning your flight so that you always have an option, keeping aware of your surroundings, and knowing how (and at what speeds) to fly your airplane when the noisemaker stops. "Deadstick" landings, on or off an airfield, are nothing of which to be afraid. I'd guess, at this point, that 95% of the landings I've ever done were "deadstick". By choice. Your airplane is just another glider, one that happens to have a poorer L/D and the towplane bolted to the nose. That's all.

If you don't care that you're reaching your intended destination, what you're actually trying to avoid is the hassle of getting the landed airplane transported out from "x" other airfield, or "y" field, road, or dry lake bed along your original route. It's not a safety issue, it's an issue of convenience. Recognize that, and it colors the discussion quite a bit.

Given the reliability of modern electronics and other systems, and looking at it with this "new" philosophy, I don't really see the need for the cost, weight, and unintended additional failure modes created by extensive redundancy. YMMV, of course.
 

pictsidhe

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Speaking of redundancy, why not duplicate critical sensors like the crank sensor? ECUs are much more reliable than their 'eyes'.
 

rv6ejguy

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Our dual ECU setups use dual crank sensors but in fact, I've never seen an electronic failure of our crank sensors yet and that's in millions of hours collectively.
 

Vigilant1

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Safely landing "out" without an engine is just another skill to learn, like stalls or short-field takeoffs. Landing "out" is a matter of planning your flight so that you always have an option, keeping aware of your surroundings, and knowing how (and at what speeds) to fly your airplane when the noisemaker stops. "Deadstick" landings, on or off an airfield, are nothing of which to be afraid. I'd guess, at this point, that 95% of the landings I've ever done were "deadstick". By choice. Your airplane is just another glider, one that happens to have a poorer L/D and the towplane bolted to the nose. That's all.

If you don't care that you're reaching your intended destination, what you're actually trying to avoid is the hassle of getting the landed airplane transported out from "x" other airfield, or "y" field, road, or dry lake bed along your original route. It's not a safety issue, it's an issue of convenience. Recognize that, and it colors the discussion quite a bit.
This is a valid way of looking at things, and taking it to heart can improve flight safety regardless of the reason for the loss of power. OTOH, there are practical considerations that can affect the situation. For instance, the factory says my Sonex has an L/D of 11:1. If I assume I'll probably get 9:1 in a real situation (getting to proper speed/configuration, etc), and I'm at 5000 AGL when things get quiet, then I'll touch ground somewhere within 7.4 NM. Since I would need to properly orient for landing, there might be wind issues, etc, that cuts the range I can count on to about 5 NM. If I'm going out of the local area, it is not practical to stay within 5NM of an airfield. Where I live, most of the year every bit of land is crops, trees, river, road, or structures--no desert. There are some more open fields where cattle graze, but from a distance it can be hard to know what is what. Setting down in most of that poses a substantial risk to safety and damage to the plane. It's amazing how much damage landing in a cornfield can do. So, while it is smart to always be thinking "what if," in practice the choices can be "unappealing," and taking fairly significant steps to avoid landing out make sense from both a safety and a cost/benefit standpoint.

Given the reliability of modern electronics and other systems, and looking at it with this "new" philosophy, I don't really see the need for the cost, weight, and unintended additional failure modes created by extensive redundancy. YMMV, of course.
For me, it will boil down to an assessment of the risk (which can be a problem for some EFI/EI systems with short aviation records) and the practicality of reducing those risks. But, back to your first point: I'd only be reducing risk due to loss of spark or fuel. Crankshaft, conrods, swallowed valves, etc would still lie in wait, and that's where "what if" planning makes sense.
Or, better yet, fly a Beetlemaster and have that other engine on hand. :)
 

Topaz

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... For instance, the factory says my Sonex has an L/D of 11:1. ...
Oh heck, that's soarable on a nice ridge day! You might never come down! :gig:

No worries. Clearly your surroundings are different than mine, where the biggest threat to landing out safely is finding a place without houses... :roll:
 

pictsidhe

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Our dual ECU setups use dual crank sensors but in fact, I've never seen an electronic failure of our crank sensors yet and that's in millions of hours collectively.
No, but you've seen the wiring damaged? They are a relatively low cost component, but utterly essential. It wouldn't be too hard to add a 2nd one on the other side of the engine with a fault detection subroutine. You wouldn't even need to locate it at a precise crank angle, you could calibrate from the main sensor.

I have had an angle sensor fail. But it worked fine until the engine had been running 20 minutes. I eventually diagnosed it in the kitchen oven...
 

rv6ejguy

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No, but you've seen the wiring damaged? They are a relatively low cost component, but utterly essential. It wouldn't be too hard to add a 2nd one on the other side of the engine with a fault detection subroutine. You wouldn't even need to locate it at a precise crank angle, you could calibrate from the main sensor.
The whole system depends on doing the wiring correctly and you could say the same for most mechanical parts on the engine too. You can't fix stupid as in the case I talked about before with the aluminum exhaust system melting through. Where do you draw the line on redundancy on a single engined aircraft- plenty of single points of failure. Do the installation correctly with the armor and fire sleeve and that scenario can't happen.

With one set of magnets and the software that has to run, you can't easily have a second sensor 180 degrees from the first one feeding that ECU. You'd be writing more code you'd have to validate and develop/test isolation hardware to feed dual sensor signals into a single input. Just more complexity, more likely to create another problem while trying to solve an issue that is extremely remote with a proper installation.
 
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