---------------------------------------------------------- Lightning-List Digest Archive --- Total Messages Posted Tue 03/24/09: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:55 AM - Re: more prop test info (selwyn) 2. 06:17 AM - Re: Re: more prop test info (Pete Krotje) 3. 08:54 AM - Re: more prop test info (jeynon) 4. 12:04 PM - Re: Re: more prop test info (Bob Haas) 5. 12:17 PM - Re: Re: more prop test info (Bob Haas) 6. 05:23 PM - Re: more prop test info (selwyn) 7. 06:54 PM - Electronic Cabin Heat Vent (Jim Langley) ________________________________ Message 1 _____________________________________ Time: 01:55:35 AM PST US Subject: Lightning-List: Re: more prop test info From: "selwyn" Hi Buz, I'll be interested to see that as I am sure will others. There is a school of thought going around which says that the coarser pitch props are too coarse and the engine is running at too high a manifold pressure for the revs. One consequence of that would be that the thing is running on lean mixture at high power settings, not necessarily a good thing. I appreciate you can't actually do much about it with a fixed pitch prop (except change the prop ) but it would be nice to know so we could operate the thing in the best way available. Of course, if we had a decent carby with a mixture control then we would be able to do something about it wouldn't we. That's on my list of possibles once the warranty expires. I'm getting towards where I can start to at least think about flying mine so I'm keen to gather all the preliminary info possible. Another two or three months and we may be getting close. -------- Cheers, Selwyn Kit 66 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=235925#235925 ________________________________ Message 2 _____________________________________ Time: 06:17:09 AM PST US From: "Pete Krotje" Subject: RE: Lightning-List: Re: more prop test info Actually Selwyn, more prop pitch will result in a richer mixture not leaner. Pete -----Original Message----- From: owner-lightning-list-server@matronics.com [mailto:owner-lightning-list-server@matronics.com] On Behalf Of selwyn Sent: Tuesday, March 24, 2009 3:54 AM Subject: Lightning-List: Re: more prop test info Hi Buz, I'll be interested to see that as I am sure will others. There is a school of thought going around which says that the coarser pitch props are too coarse and the engine is running at too high a manifold pressure for the revs. One consequence of that would be that the thing is running on lean mixture at high power settings, not necessarily a good thing. I appreciate you can't actually do much about it with a fixed pitch prop (except change the prop ) but it would be nice to know so we could operate the thing in the best way available. Of course, if we had a decent carby with a mixture control then we would be able to do something about it wouldn't we. That's on my list of possibles once the warranty expires. I'm getting towards where I can start to at least think about flying mine so I'm keen to gather all the preliminary info possible. Another two or three months and we may be getting close. -------- Cheers, Selwyn Kit 66 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=235925#235925 ________________________________ Message 3 _____________________________________ Time: 08:54:33 AM PST US Subject: Lightning-List: Re: more prop test info From: "jeynon" So Buz, if my interpolation skills are up to par, you could shut off your fuel altogether and cruise all day at 100 mph. [Shocked] John Eynon Lightning kit #53 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=235971#235971 ________________________________ Message 4 _____________________________________ Time: 12:04:04 PM PST US From: "Bob Haas" Subject: RE: Lightning-List: Re: more prop test info I would like to check the manifold pressure also. I will have a manifold pressure gage and will see just how hard my Sensenich Ground adjustable prop is working at given airspeeds and rpm. Bob Haas N330BH. _____ From: owner-lightning-list-server@matronics.com [mailto:owner-lightning-list-server@matronics.com] On Behalf Of N1BZRich@aol.com Sent: Monday, March 23, 2009 8:37 PM Subject: Re: Lightning-List: Re: more prop test info In a message dated 3/23/2009 8:05:16 P.M. Eastern Daylight Time, selwyn@ellisworks.com.au writes: I'd really like to see these numbers with RPM and manifold pressure information. OK, Selwyn, I do have manifold pressure (MP), so can eventually get that for you. Currently I don't pay that much attention to MP (fixed pitch prop) and I got it installed too late to be much help during the initial 40 hour test phase. I ordered the MP set up early on, but there was a delay in getting it to me. I wanted to use it to help with the % horse power charts, but I was about done with the phase one testing before I got it installed. I guess I just have been too busy to do much with it since then. But as I said, I will get some info for you if you promise to write something up about it and the Bing adjustments for the newsletter. Just keep bugging me about it until I get it done. Buz _____ Feeling the pinch at the grocery store? Make dinner for $10 or less. 06:52:00 ________________________________ Message 5 _____________________________________ Time: 12:17:25 PM PST US From: "Bob Haas" Subject: RE: Lightning-List: Re: more prop test info I concur, but if you have an adjustable prop one can manage the engine Some what with the Bing. Bob Haas. -----Original Message----- From: owner-lightning-list-server@matronics.com [mailto:owner-lightning-list-server@matronics.com] On Behalf Of selwyn Sent: Monday, March 23, 2009 8:03 PM Subject: Lightning-List: Re: more prop test info Hi Buz, I'd really like to see these numbers with RPM and manifold pressure information. With the Bing the only control you have over mixture is via the airflow through the carby, set by the revs, so those numbers help to understand what regieme the engine is operating in. The manifold pressures help to understand this a little more. To my mind, the fuel flow figures in isolation are very little help in understanding what is going on in the engine and one needs an appreciation of that to make valid propeller comparisons. Cheers, Selwyn -------- Cheers, Selwyn Kit 66 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=235877#235877 Checked by AVG - www.avg.com 06:52:00 ________________________________ Message 6 _____________________________________ Time: 05:23:40 PM PST US Subject: Lightning-List: Re: more prop test info From: "selwyn" pete(at)flylightning.net wrote: > Actually Selwyn, more prop pitch will result in a richer mixture not leaner. > > Pete > > -- Hi Pete, Sorry, I don't follow that one. My understanding is that what will set the mixture is a combination of throttle opening and engine revs. Engine revs is the critical thing because it affects the flow through the carby and thence the needle position which is what regulates the mixture. The profile of the needle has to match the operating rev band. >From that, if you imagine an engine with a variable pitch prop and you run it with a wide open throttle and the thing is running somewhere near max revs, the needle will be right out and it will be running rich mixture with most of the needle profiles we are likely to use. If we then start winding in pitch the revs will come back as we load the engine and somewhere a little under 3000 RPM the mixture will start to lean off as the flow through the carby throat decreases and the needle begins to descend. If we keep winding in pitch we will end up at 2850 cruise revs, wide open throttle and a nice lean cruise mixture, high manifold pressure, probably good cruise performance but an engine waiting to go bang. That's my theory of how the Bing works. I would be very pleased to see debate from the experts. -------- Cheers, Selwyn Kit 66 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=236039#236039 ________________________________ Message 7 _____________________________________ Time: 06:54:04 PM PST US From: "Jim Langley" Subject: Lightning-List: Electronic Cabin Heat Vent Here's a little tidbit that I know Nick can relate to because he's a fellow RC'r. Instead of using the cable to control the vent for my cabin heat, I am using a 12v-5v regulator, servo tester and Hitec Digital servo. The servo will be mounted on the firewall, connected to the vent with a Hangar 9 titanium control link. The servo is a standard RC digital servo that came out of one of my big rc airplanes and has about 180lbs of torque. This is what I had handy, although a 60-80lb servo would work fine. I built the voltage regulator from parts and the following plans, http://www.mybitbox.com/articles/standalone-voltage-regulator/ I also built a simple servo tester which is not much more than a 555IC, and some cheap parts from Radio Shack with a pot to control the servo travel. The servo will move throughout its range as fast as you turn the dial, so you can open or close the vent pretty fast. I will be mounting the servo tester, (heat control like on a car dash), on my center console along with my master/EFIS switch and my flap position selector; (see my crude drawing). The nice thing about the Hitec servos is that they are pretty robust when it comes to heat, and are programmable for arm travel. All in all, $59.00 for the servo and $12.00 for the rest of the parts, plus some solder time = total of $71.00 for a digitally actuated heater vent! If you want to go cheaper, use a HS-75BB with 100lbs of torque. It is used a lot for robotics and only costs $29.00! http://www.servocity.com/html/hs-75bb_retract.html What I used is over kill, but was lying around and not being used. I will write up something with pictures after it is installed. Jim! ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message lightning-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Lightning-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/lightning-list Browse Digests http://www.matronics.com/digest/lightning-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.