gibbon

2 minutes ago, h4nd said:

Send me a pic of it's innards, and I'll tell you how to goose it. The resistor is gonna cost you 12c

Actually here's a tangental question - what we do have already is a 3 phase fed 28v DC ground power unit for starting turbines, how do I tap off a 14v feed from that without frying myself? it's the size of a doghouse and good for 200a 

5 minutes ago, h4nd said:

2 || lipo, easy.

Oh, you can has mains? Well, is 2Fiddy too much? https://www.jaycar.co.nz/13-8v-40a-switchmode-bench-power-supply/p/MP3089?gclid=Cj0KCQjwi7GnBhDXARIsAFLvH4mmOTYQPrmYhm-zriE338bz0AvlewRgMaoQkyPeuknaqPXv3SryrKIaAqK6EALw_wcB

voltage is marginal but I reckon that'd do it 

people have shit to say when they see that sort of ingenuity hanging off their aircraft 

Another option would be running thirteen 14v 3a laptop chargers in parallel but I'd have to package it real nice 

1 hour ago, tortron said:

Would a big old battery charger put that out. 

My one on wheels puts out a shit load of amps (cauge starts at about 20 and goes to 60) at about 14v

That must be a beast of a charger... Ours is a big (and old) benchtop one but I think it tops out at 10a

... are you sure it's not an arc welder lol 

I'll bolt an alternator to an angle grinder and post results 

18v is probably a bit much... Surely pulling 40 amps from that would melt it into a puddle? 

what's the best way of getting a 14v battery for cheap? I need 14v able to provide at least 40 amps for a minute or two. Basically I need a regular battery with an extra cell? We've just jumped off a running engine in the past but it's a bit of a pain in the ass 

I used an oil pressure cutout and bridged the relay on demand with a "prime" button that sortof doubles as a security system because it's a repurposed aircon button

I had a piss poor experience with weber specs tbh

what if she asks difficult questions like "why do none of these guys actually have old cars" 

A GIRL!!?!?

While I do have several operators who have policies of never reusing decanted avgas, - resulting in enough to run my lawnmower for a trillion years - it really really was just a hypothetical question 

yeah good point - the rotax would probably throw a fit if you started giving it the sort of throttle input that a car gets

also generally these EFI aircraft engines have a constant speed prop attached, so even if it did ran sub-optimally for a few seconds while it got it's EGT feedback, the prop would just fine out to keep the RPM constant, so you'd see a decrease in MAP instead and have a mathematical decrease in airspeed but you probably wouldn't even feel it. same setup in a car and there'd be bogging down, RPM decay etc

moral of the story is carbys rule

Come to think of it we look after a couple of machines with fuel injected rotax engines that don't have manual mixture adjustment, can run avgas, and don't have o2 sensors... They must be able to compensate for altitude somehow and I can't imagine they do it without some kind of feedback. The ecu is definitely not connected to the altimeter 

@Roman it genuinely is a question of pure academic curiosity 

Ok so my takeaway here is that a wideband is more of a tuning aid than anything else? I guess cars trundle around in open loop from time to time anyway. Still I'm curious to know the answer from a hypothetical point of view - can an ecu extrapolate meaningful feedback with an EGT sensor rather than o2

5 hours ago, yoeddynz said:

@gibbon ask @kws just how much difference a wideband can make - if only to economy.

 

I was trying to see if it were feasible to have something akin to wideband feedback, without having an actual wideband sensor, for avgas reasons 

more importantly how is the escargot going 

With enough inputs (air & fuel flows, map and EGT for a start) could an ecu do away with an o2 sensor but still run closed loop?

Nothing like picking up someone's daughter for the prom in your sedan featuring a spacious full sized rear seat 

I'm not in. My day sucked and I'd love to complain in person but I've started feeling like shit so just going to crash out. fuck a burger would be so good right now though 

I'm in 

I hope

Haven't asked the wife 

WPC collects 400l or more for free, so presumably a truck service centre wouldn't care if you chucked yours in their dump. I've got a 995l hopper and all the locals make the most of it because I'm community minded/utterly powerless to stop them