Cold Start Screw up?

GeorgeC said:
How long do the nozzles last? What about the labor to replace them?
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They should be good for several thousand hours, but in the flight school with its frequent primes and starts, I'd find them clogging up after maybe 2000 hours.

Quick and easy to replace in most cases. Undo the tube nut, back out the primer (1/8" NPT), screw in new nozzle and reconnect the tube.

1706220250743.png

https://www.aircraftspruce.com/catalog/hapages/primperfittingsan4022-1.php

There's a 90° angled version you'll find on the carbureted O-470s, common in airplanes like the 180 and older 182s. It shoots the prime into the aft end of the intake runners. We had a hard-to-start 180 come in for an annual, and I found AN822-2D elbows in the runners. The primer was just pouring fuel into them, no atomization at all. One has to wonder sometimes...
 
Country Flier said:
I read an article, albeit regarding car engines, that said if you start a cold car on a 20F day, and drive 200 miles, you do more wear during the first 2 miles when the engine is still cold than the remaining 198 miles. The article did say the engine wear is very light, but still more in the first 2 than the remaining 198 was meaningful to me.
I preheat every engine I own in winter...my truck, my tractor, my plane.

But OP, I wouldn't think one cold start, within manufacture specifications, wouldn't cause harm.
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You do the nearly the same on an 80F day as well. Any mechanic or automotive engineer will tell you that 90% of engine wear occurs on startup.
 
Sac Arrow said:
You do the nearly the same on an 80F day as well. Any mechanic or automotive engineer will tell you that 90% of engine wear occurs on startup.
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This is one of several reasons I dislike cars with stop/start, but maybe the manufacturers know something that I don't...
 
GeorgeC said:
This is one of several reasons I dislike cars with stop/start, but maybe the manufacturers know something that I don't...
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I am just spitballing here, as I have no research or other hard data to back this up, but consider please that the stop/start cars have a fully lubricated, warm engine for all but the initial few starts of the automotive trip. No “drip time” for that engine. That has to minimize the wear for most of the starts on a trip.

That doesn’t help it over night or longer engine off periods. Just as with our aircraft engines.

Anyone have any hard data that applies here?

-Skip
 
Skip Miller said:
I am just spitballing here, as I have no research or other hard data to back this up, but consider please that the stop/start cars have a fully lubricated, warm engine for all but the initial few starts of the automotive trip. No “drip time” for that engine. That has to minimize the wear for most of the starts on a trip.

That doesn’t help it over night or longer engine off periods. Just as with our aircraft engines.

Anyone have any hard data that applies here?

-Skip
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The feature is too new for hard data to kick in. But remember that journal bearings require both movement and forced oil in order to float. Once movement stops, you are back to metal to metal contact. Yes hot starts are better than cold starts, but I'll bet these engines aren't going much past 100K.

I'd love to see real world feedback on that.
 
Yeah, the on/off thing doesn't address the root problem - stopping all the time. Airplanes don't stop in mid air, why should cars stop all the time? Change stop sign and red light enforcement to yield rather than full stop, and knock it off with the environmental regulations for the next 50 or so years.
 
Albany Tom said:
Yeah, the on/off thing doesn't address the root problem - stopping all the time. Airplanes don't stop in mid air, why should cars stop all the time? Change stop sign and red light enforcement to yield rather than full stop, and knock it off with the environmental regulations for the next 50 or so years.
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There are people who do this stuff for a living, and I'm not one of them, but that's never stopped me from engaging in Deep Thoughts(tm). Prepare to mix aviation and telecom metaphors!

It would be nice if car traffic were circuit-switched instead of packet-switched. I think there are issues at the local scale (ie, it takes me 15 minutes to go a couple miles, because I need to stop at every block, even if there are no other cars) and at a larger scale (I want to go 25 miles away, but there are too many other cars between me and where I want to go).

For the "local" issues of not hitting anything and deconflicting traffic, I sometimes wonder, instead of the machine vision moonshot timeline we appear to be in, if equipping cars with short-range peer-to-peer transponders would have been an easier path to driver assist + less traffic + fewer accidents.

For the "global" problem, in the same way that some highways meter incoming traffic, one could imagine an IFR-like system for cars, where the route gets planned with traffic flow control in mind. You don't go until you are cleared, but once you are, it's as though you have the road to yourself.
 
GeorgeC said:
There are people who do this stuff for a living, and I'm not one of them, but that's never stopped me from engaging in Deep Thoughts(tm). Prepare to mix aviation and telecom metaphors!

It would be nice if car traffic were circuit-switched instead of packet-switched. I think there are issues at the local scale (ie, it takes me 15 minutes to go a couple miles, because I need to stop at every block, even if there are no other cars) and at a larger scale (I want to go 25 miles away, but there are too many other cars between me and where I want to go).

For the "local" issues of not hitting anything and deconflicting traffic, I sometimes wonder, instead of the machine vision moonshot timeline we appear to be in, if equipping cars with short-range peer-to-peer transponders would have been an easier path to driver assist + less traffic + fewer accidents.

For the "global" problem, in the same way that some highways meter incoming traffic, one could imagine an IFR-like system for cars, where the route gets planned with traffic flow control in mind. You don't go until you are cleared, but once you are, it's as though you have the road to yourself.
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I like the concept just because I remember when a lot of networking was CSMA/CD (Ethernet w/out switching) which is a little bit like the way cars work. Look left and right and step on the gas, if you see a crash avoid it.

We already have local systems that can detect a signal from an emergency vehicle and give it a green light. It wouldn't be much different to combine real time traffic information with signal control, and make that 3am trip to the convenience store stop-less.

Maybe when the current semi-auto driving cars that sometimes run over firemen are replaced with something new, the freeways will work like that. You get on the ramp, the autopilot takes over, and merges you with traffic. I don't like self driving, but if a system like that would let the highway speeds increase to about 120mph, then it might make sense.
 
Albany Tom said:
I like the concept just because I remember when a lot of networking was CSMA/CD (Ethernet w/out switching)...
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Same. I always admired the eleganace of simple decentralized systems that figure out how fast to go on their own and manage to avoid congestion collapse.
 
Skip Miller said:
I am just spitballing here, as I have no research or other hard data to back this up, but consider please that the stop/start cars have a fully lubricated, warm engine for all but the initial few starts of the automotive trip. No “drip time” for that engine. That has to minimize the wear for most of the starts on a trip.

That doesn’t help it over night or longer engine off periods. Just as with our aircraft engines.

Anyone have any hard data that applies here?

-Skip
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I have read in several places that some kind of polymer coating is being used to address start-stop operating conditions, for example:

Polymeric Engine Bearings for Hybrid and Start Stop Applications

The implementation of legislations to ban the usage of lead as an alloying element in internal combustion engines and incrementally reducing emission output is having a fundamental impact on the design and function of half bearings. It has been witnessed that bearing operating environments are becom
www.sae.org www.sae.org
 
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