I don't think that is too crucial - once you have properly planned your flight, and you are flying the plan, the engine settings determine your fuel economy. You know how much fuel you have - you used your dip stick, didn't you? Of course, you would never trust the gauges - but actually have a computer determining the best setting for the mixture would be much easier than having the pilot fiddling with the control. How accurate is peak EGT less 25degC? Let a PIC measure the EGT, and control the mixture to within pre-set tollerances. This will stretch your gallons per seat mile. And this will be moot when you fly a C208 or such. Regards Chris A ----- Original Message ----- From: "Pic Dude" To: Sent: Saturday, 15 June, 2002 16:19 Subject: Re: [EE]: Airplane cruise control Hmmm.... not sure if this is clear or not, but I'll say it just in case. On an airplane, engine RPM is not directly proportional to groundspeed (which is not the same as airspeed, btw). My guess is that you want to be able to maintain a constant groundspeed, so there will need to be some sensor(s) to gauge that, and perhaps GPS is the way to go. Also, revs are not proportional to fuel consumption. Not just in airplanes, but also in cars. Speaking of fuel, if you really want to do something useful for the aviation community, how about building a fuel gauge that senses the level at various points, and perhaps also the motion of the aircraft to mathematically calculate a more accurate fuel-level. Cheers, -Neil. -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Jinx Sent: Saturday, June 15, 2002 6:00 AM To: PICLIST@MITVMA.MIT.EDU Subject: Re: [EE]: Airplane cruise control > Ummm, not self-flying? So exactly what purpose DOES > a cruise control serve? It's exactly the same as cruise control in a car. I spoke to the actual person who wants the job done today. If I understand him correctly it means less work for the pilot making minor corrections to engine RPM during a flight. I presume from this that it would make it easier to some degree to gauge fuel usage if the engine is running at the same revs from take-off to landing, as well as probably a more comfortable flight for all concerned. He told me that on a recent trip from Queenstown to Auckland (about 225mm. Hang on, it's more than that surely. Oh right, there's a scale, er 700 miles) he noted that the pitch control on this 4-seater cycled about half a dozen times, but it was pretty clear air most of the way He gave me some more details. The prop needs to be held at a selectable speed betrween 2000 and 3000 rpm. There are 6 magnetic sensors on the prop shaft that output 200 to 300Hz (eg (2000/60) * 6). There was also talk of adjustment time, pilot controls, operational stuff like that. It's reasonably straight-forward > small embedded consultants Can't argue with that. I'm 5'3" and people are always consulting me. Like, "just when ARE you getting up ?" > are approached to design ANYTHING even related to self > flying aeroplanes you have to be a bit suspicious. I wasn't concerned at all. To be honest, I didn't hear much after the word "job" except a distant cash register going "ching ching ching". One of "those" weeks. And NZ is so small you can get up in the air and pretty well point out anywhere in the country. GPS ? Waste o' money here. Security is nowhere near as tight as you'd see in the US for example and it would be easy to damage any of many soft targets you wanted to with devices other than a plane. And why would you bother with a light plane anyway ? Look at the student who hit that building (the only high rise in a European town) with a light plane. And I think one in Florida too. Broke a couple of windows and killed themselves doing it > And the added bit "I was contacted through an intermediary" > really made me grin If you've ever spoken to my acquaintance old Mr Harris you'd be thinking that a terrorist organisation could do a little better than use "him" as a go-between. He's not what you'd call "perky" > Did the intermediary insist on a meeting on a park bench > where the design plans were handed over inside a folded > newspaper? ;o) Well yes actually. But it was no bother - I was already down the park trying out the new E-Z-Flash raincoat. Which is really great btw, the 2002 VelcroMatic, beats buttons on a cold finger- numbing day I can tell you -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu