RE: [Flightgear-devel] Instrument help
It looks like the switch is marked CHT Select in the top part of the image. Does this aircraft have a 4 cylinder engine by any chance? Richard -Original Message- From: WillyB [mailto:[EMAIL PROTECTED] Sent: 28 July 2003 8:10 pm To: FlightGear developers discussions Subject: Re: [Flightgear-devel] Instrument help H Ok, I'm probably confusing the switch then. I resized and enhanced the photos and have attached the new one I made from it. Is that 4 position switch for the C HT or am I totally wrong on that? Re's WillyB On Monday 28 July 2003 11:42, Alex Perry wrote: From: Matthew Law [EMAIL PROTECTED] If ther eis a switch for CHT .. would this be so you can manually adjust the temp if needed? No. Cylinder Head Temp is usually used to help you assess the health of your engine. CHT itself doesn't have a switch, it is purely a measurement. _However_ ... * Some people put EGT and CHT on the same dial and need a switch to select which output is being shown at any given time. * Like EGT, it is often useful to have a peak hold feature, in which case you need a switch to disable the peak hold. * You normally have one CHT sensor per cylinder (sometimes two), so you either need to have lots of dials, or a switch to select among them, or an electronic display to cycle through them, etc. * On a racing aircraft, I might be tempted to connect an autothrottle to the CHT (with a switch to disable it), just like a lot of acft have an autolean that operates the mixture on carburated engines. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument help
On Tuesday 29 July 2003 00:42, Richard Bytheway wrote: It looks like the switch is marked CHT Select in the top part of the image. Does this aircraft have a 4 cylinder engine by any chance? Yes, it uses the Continental 0-200 (100 HP) which is 4 cylinder. From what I understand now the switch will switch between the 4 cylinders and the selected cylinder's temp will be displayed in the cht instrument. Thanks for taking a look at it :) Re's WillyB Richard -Original Message- From: WillyB [mailto:[EMAIL PROTECTED] Sent: 28 July 2003 8:10 pm To: FlightGear developers discussions Subject: Re: [Flightgear-devel] Instrument help H Ok, I'm probably confusing the switch then. I resized and enhanced the photos and have attached the new one I made from it. Is that 4 position switch for the C HT or am I totally wrong on that? Re's WillyB On Monday 28 July 2003 11:42, Alex Perry wrote: From: Matthew Law [EMAIL PROTECTED] If ther eis a switch for CHT .. would this be so you can manually adjust the temp if needed? No. Cylinder Head Temp is usually used to help you assess the health of your engine. CHT itself doesn't have a switch, it is purely a measurement. _However_ ... * Some people put EGT and CHT on the same dial and need a switch to select which output is being shown at any given time. * Like EGT, it is often useful to have a peak hold feature, in which case you need a switch to disable the peak hold. * You normally have one CHT sensor per cylinder (sometimes two), so you either need to have lots of dials, or a switch to select among them, or an electronic display to cycle through them, etc. * On a racing aircraft, I might be tempted to connect an autothrottle to the CHT (with a switch to disable it), just like a lot of acft have an autolean that operates the mixture on carburated engines. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument help
Matthew Law writes: IIRC, running lean at high power settings increases CHT. Running rich decreases it since there is more fuel to help dissipate heat. That's an OIT (Old Instructor's Tale) as far as I can tell, though I'm sure that a little heat gets carried off that way. What actually seems to control the CHT is the efficiency of combustion. The hottest CHT's come at about 50 degF rich of peak EGT (ROP), and the greatest power comes at 100 degF ROP. At peak EGT, CHT's will be already be getting cooler, and they start to drop significantly as you go lean of peak EGT (LOP). By 50 degF LOP, CHTs will have dropped nearly 20 degC -- you need to run almost 250 degF ROP to get the same result. In other worlds, 50 degF ROP is the hottest the engine will run -- either leaning or enriching the mixture from that point will make the engine run much cooler, but you have to lean only a little, while you have to enrich quite a bit to get the same effect (bringing on the joy of fouled plugs, stuck values, high fuel consumption, and lots of carbon monoxide in your exhaust). You can find a little chart in any Lycoming (or, presumably, Continental) engine manual showing how all this works -- I bought my O-320 manual on eBay for almost nothing. All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument help
Arnt Karlsen writes: ...except when running lean-of-peak, where leaning further, lowers CHT further. Anything lean of 50 degF rich of peak EGT will result in lower CHT. Running right at peak is already slightly cooler, though only by a few degrees. All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument help
Alex Perry writes: Individual cylinders have slightly more or less airflow cooling (due to the pattern of baffles in front of the firewall) and receive slightly different richness in the mixture (due to fuel injection differences, or uneven atomization after the carbureter as appropriate). For each engine (and baffle layout), the pattern of differences is generally well known and the behavior is pretty consistent across most of the fleet. After enough experience in an aircraft, many owners know which cylinder is going to be hottest for a given phase of flight and therefore can leave the switch in a single position, just changing it (eg) after climb ends. Periodically, the pilot will cycle through all the cylinders to make sure they all read as expected, as a way of detecting some imminent failures. Nowadays, a lot of people are installing inexpensive engine monitors like the EDM 700: http://www.jpinstruments.com/edm_700.html It cycles through all the information and will display whatever you want (i.e. hottest cylinder) automatically. It also keeps track of all its incoming data and allows you to download it to your computer and make charts in your spreadsheet, etc., so it's a bit like a poor-man's flight data recorder. It's also considerably cheaper than other toys like an IFR GPS or a Stormscope. All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument help
If ther eis a switch for CHT .. would this be so you can manually adjust the temp if needed? No. Cylinder Head Temp is usually used to help you assess the health of your engine. If it is running too hot it is likely to shorten the life of the engine. If it is running really hot then it's probably about to die very soon. IIRC, running lean at high power settings increases CHT. Running rich decreases it since there is more fuel to help dissipate heat. In the context of a racer, CHT is helpful in knowing if you can push your engine a little harder without blowing it I suppose. Then again, I might be totally wrong! Cheers, Matt. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument help
From: Matthew Law [EMAIL PROTECTED] If ther eis a switch for CHT .. would this be so you can manually adjust the temp if needed? No. Cylinder Head Temp is usually used to help you assess the health of your engine. CHT itself doesn't have a switch, it is purely a measurement. _However_ ... * Some people put EGT and CHT on the same dial and need a switch to select which output is being shown at any given time. * Like EGT, it is often useful to have a peak hold feature, in which case you need a switch to disable the peak hold. * You normally have one CHT sensor per cylinder (sometimes two), so you either need to have lots of dials, or a switch to select among them, or an electronic display to cycle through them, etc. * On a racing aircraft, I might be tempted to connect an autothrottle to the CHT (with a switch to disable it), just like a lot of acft have an autolean that operates the mixture on carburated engines. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument help
H Ok, I'm probably confusing the switch then. I resized and enhanced the photos and have attached the new one I made from it. Is that 4 position switch for the C HT or am I totally wrong on that? Re's WillyB On Monday 28 July 2003 11:42, Alex Perry wrote: From: Matthew Law [EMAIL PROTECTED] If ther eis a switch for CHT .. would this be so you can manually adjust the temp if needed? No. Cylinder Head Temp is usually used to help you assess the health of your engine. CHT itself doesn't have a switch, it is purely a measurement. _However_ ... * Some people put EGT and CHT on the same dial and need a switch to select which output is being shown at any given time. * Like EGT, it is often useful to have a peak hold feature, in which case you need a switch to disable the peak hold. * You normally have one CHT sensor per cylinder (sometimes two), so you either need to have lots of dials, or a switch to select among them, or an electronic display to cycle through them, etc. * On a racing aircraft, I might be tempted to connect an autothrottle to the CHT (with a switch to disable it), just like a lot of acft have an autolean that operates the mixture on carburated engines. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel attachment: chtimg.jpg___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument help
The engine has four cylinders and the four-position switch in question allows the pilot to select between four Cylinder Head Temperature sensors (one in each cylinder head). Kris WillyB wrote: H Ok, I'm probably confusing the switch then. I resized and enhanced the photos and have attached the new one I made from it. Is that 4 position switch for the C HT or am I totally wrong on that? Re's WillyB On Monday 28 July 2003 11:42, Alex Perry wrote: From: Matthew Law [EMAIL PROTECTED] If ther eis a switch for CHT .. would this be so you can manually adjust the temp if needed? No. Cylinder Head Temp is usually used to help you assess the health of your engine. CHT itself doesn't have a switch, it is purely a measurement. _However_ ... * Some people put EGT and CHT on the same dial and need a switch to select which output is being shown at any given time. * Like EGT, it is often useful to have a peak hold feature, in which case you need a switch to disable the peak hold. * You normally have one CHT sensor per cylinder (sometimes two), so you either need to have lots of dials, or a switch to select among them, or an electronic display to cycle through them, etc. * On a racing aircraft, I might be tempted to connect an autothrottle to the CHT (with a switch to disable it), just like a lot of acft have an autolean that operates the mixture on carburated engines. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument help
From: WillyB [EMAIL PROTECTED] Ok, I'm probably confusing the switch then. I resized and enhanced the photos and have attached the new one I made from it. Is that 4 position switch for the C HT or am I totally wrong on that? Url : http://mail.flightgear.org/pipermail/flightgear-devel/\ attachments/20030728/02418d4a/chtimg.jpg Aha! Nicely enhanced; it resolves the confusion. The two switches lower left are the magnetos as you've already figured out. The rotary analog display is labelled CYL HEAD TEMP and only has one needle (white) and the redline (which is irrelevant to the discussion). From: Alex Perry [EMAIL PROTECTED] * You normally have one CHT sensor per cylinder (sometimes two), so you either need to have lots of dials, or a switch to select among them, or an electronic display to cycle through them, etc. The metal control (without a knob) is shown, in both the drawing and the panel, with four positions and, in the drawing, is labelled CHT select. I therefore assert that this aircraft has a four cylinder engine and this selects which cylinder measurement is going to be seen on the dial. Individual cylinders have slightly more or less airflow cooling (due to the pattern of baffles in front of the firewall) and receive slightly different richness in the mixture (due to fuel injection differences, or uneven atomization after the carbureter as appropriate). For each engine (and baffle layout), the pattern of differences is generally well known and the behavior is pretty consistent across most of the fleet. After enough experience in an aircraft, many owners know which cylinder is going to be hottest for a given phase of flight and therefore can leave the switch in a single position, just changing it (eg) after climb ends. Periodically, the pilot will cycle through all the cylinders to make sure they all read as expected, as a way of detecting some imminent failures. As far as simulating it is concerned, there are standard models for how CHT changes as a function of operating conditions for a given cylinder. Therefore, we could easily have per-cylinder parametrics for the cooling and for the mixture (in the engine file) that drive a standard CHT model. Those parametric values, plus the broken status of each CHT sensor, would be accessible to the instructor through the property tree. Hope that helps ... ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument help
Thanks Kris That makes sense :) WillyB On Monday 28 July 2003 12:34, Kris Feldmann wrote: The engine has four cylinders and the four-position switch in question allows the pilot to select between four Cylinder Head Temperature sensors (one in each cylinder head). Kris WillyB wrote: H Ok, I'm probably confusing the switch then. I resized and enhanced the photos and have attached the new one I made from it. Is that 4 position switch for the C HT or am I totally wrong on that? Re's WillyB On Monday 28 July 2003 11:42, Alex Perry wrote: From: Matthew Law [EMAIL PROTECTED] If ther eis a switch for CHT .. would this be so you can manually adjust the temp if needed? No. Cylinder Head Temp is usually used to help you assess the health of your engine. CHT itself doesn't have a switch, it is purely a measurement. _However_ ... * Some people put EGT and CHT on the same dial and need a switch to select which output is being shown at any given time. * Like EGT, it is often useful to have a peak hold feature, in which case you need a switch to disable the peak hold. * You normally have one CHT sensor per cylinder (sometimes two), so you either need to have lots of dials, or a switch to select among them, or an electronic display to cycle through them, etc. * On a racing aircraft, I might be tempted to connect an autothrottle to the CHT (with a switch to disable it), just like a lot of acft have an autolean that operates the mixture on carburated engines. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument help
Ah.. ok.. C H .. Cylinder Head... go figure! Thank you Mish :-)) Re's WillyB On Saturday 26 July 2003 23:21, Wg Cdr BB Misra, VSM \(Retd\) wrote: Willi, It is Cylinder Head Temperature. - Mish - Original Message - From: WillyB [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: 27 July, 2003 10:56 AM Subject: [Flightgear-devel] Instrument help Hi... I'm starting to get the instruments onto the Cassutt Racer and came accross one that is called CH or C HT or something like that... and I don't have any idea what it is... I've thought about it but my brain can't come up with the answer so thought I'd ask here as most of you probably know ;) Here are two photos that I found somewhere out there on the www... and is where I found the instrument ref'd. http://24.121.17.106/fgfs/cassutt-racer/instruments.html TIA for any insight. Regards! William McRaven ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
re: [Flightgear-devel] Instrument help
WillyB writes: I'm starting to get the instruments onto the Cassutt Racer and came accross one that is called CH or C HT or something like that... and I don't have any idea what it is... Cylinder Heat Temperature -- it's the main indication of how hot your engine is running (Exhaust Gas Temperature -- EGT -- is more for leaning the mixture). CHT gauges are common on large engines, but very rare on the little 140-180 hp engines used in entry-level aircraft. All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument help
On Sun, 27 Jul 2003 08:57:38 -0400, David Megginson [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]: WillyB writes: I'm starting to get the instruments onto the Cassutt Racer and came accross one that is called CH or C HT or something like that... and I don't have any idea what it is... Cylinder Heat Temperature -- it's the main indication of how hot your engine is running (Exhaust Gas Temperature -- EGT -- is more for leaning the mixture). CHT gauges are common on large engines, but very rare on the little 140-180 hp engines used in entry-level aircraft. ..the Cassutt Racer is hardly an entry-level plane. ;-) ..that said, many EAA types cram in some weird instruments because I got it cheap and it works and I like it, so your best option is simply ask for close-ups. ..telling 'em about FG _might_ land you an invitation to take your own shots of the real bird. ;-) -- ..med vennlig hilsen = with Kind Regards from Arnt... ;-) ...with a number of polar bear hunters in his ancestry... Scenarios always come in sets of three: best case, worst case, and just in case. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Instrument help
On Sunday 27 July 2003 07:12, Arnt Karlsen wrote: On Sun, 27 Jul 2003 08:57:38 -0400, David Megginson [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]: WillyB writes: I'm starting to get the instruments onto the Cassutt Racer and came accross one that is called CH or C HT or something like that... and I don't have any idea what it is... Cylinder Heat Temperature -- it's the main indication of how hot your engine is running (Exhaust Gas Temperature -- EGT -- is more for leaning the mixture). CHT gauges are common on large engines, but very rare on the little 140-180 hp engines used in entry-level aircraft. ..the Cassutt Racer is hardly an entry-level plane. ;-) ..that said, many EAA types cram in some weird instruments because I got it cheap and it works and I like it, so your best option is simply ask for close-ups. I've emailed the company who makes the Cassutt Racer (and the Sport model). The planes are kit planes and you have to put them together yourself :) The company told me they would send me more details on the deminsions, but have not heard back from them since. :/ ..telling 'em about FG _might_ land you an invitation to take your own shots of the real bird. ;-) Now that would be totally Kool! The pics are from a site about a guy who is documenting building a racer. So the panel is from a racer. I've been lookign for the site I got those photos from but have not found it again.. yet ;) There is also a switch it on the left w/ what looks like 4 positions it and is marked as CHT Selected. I have not seen anywhere stated that there has to be any certain instruments onboard, but I know they check the engine out very thouroughly before and after the race... to see how much oil it can hold.. to see the diameter and depth of the carb.. etc. There is no room for error in that area and the weight has to be the same for all planes.. they add weight to them if they are under weight when the pilot is seated in the plane. It probably takes longer for the pre post flight checks than for the race it'self. If ther eis a switch for CHT .. would this be so you can manually adjust the temp if needed? Re's WillyB ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
[Flightgear-devel] Instrument help
Hi... I'm starting to get the instruments onto the Cassutt Racer and came accross one that is called CH or C HT or something like that... and I don't have any idea what it is... I've thought about it but my brain can't come up with the answer so thought I'd ask here as most of you probably know ;) Here are two photos that I found somewhere out there on the www... and is where I found the instrument ref'd. http://24.121.17.106/fgfs/cassutt-racer/instruments.html TIA for any insight. Regards! William McRaven ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
