Hangar Flying => Hangar Flying => Topic started by: allen on September 09, 2007, 09:40:29 PM
Title: Temps for the O-320 160hp
Post by: allen on September 09, 2007, 09:40:29 PM
I’m a new owner and have a few questions about the proper care and feeding of an O-320. I have CHT’s for all four hamsters and two EGT’s. The exhaust system is 2-into-1 so I have one EGT for each side. The pervious owner also mounted a temperature probe to monitor the carburetor temp.
I have a few questions for you vets out there. What is a good cruise RPM and what temps are you seeing? What temperature spread are you seeing between each of the cylinders? What temperature are you seeing for long climbs and dissents? What power settings are you using to descend in order to avoid shock cooling?
The book says not to go above 425 degrees. My A&P says that anything above 325 is cause for alarm and I'm seeing my number three in the 350 range in cruise at 2500rpm. Number 4 reads right about 300 or so. One and two are both high 200's. Left side EGT runs 1090 and the right side runs about 1300.
After looking at Bill James and his set up I am inclined to build a similar set up.
The plane is a dream to fly! Landing this thing takes some getting use to.
Allen N701DS
Title: Temps for the O-320 160hp
Post by: rglos on September 10, 2007, 01:08:31 PM
I see you have the P-51 style scoop. Where are your probes? on the top plugs, bottom plugs or bayonets on the bottom.
There have been many discussions on this.I searched all the forums and the consensus is that on updraft cooling the sensors should be on the top and on down draft cooling, on the bottom. If you have the thermistors on the top and are running the temps that you are, then you have no problems
The "Lycoming" hand book I have on the O 235 and O 290 lists the Cylinder max temps at 500 degrees F and Oil temps at 245 degrees F.
I'm breaking in a completely overhauled engine and still running the break in oil but I too would like to research better cooling. The baffles shown in one of the Cp newsletters did nothing for me. To be fair, I should wait untill the engine has some more hours on it before going further.
I ran the old engine with no CHT probes for 20 years. I was nearing 2000 hours when I had it overhauled so I can't say it was due to any worn out jugs but without the probes I can't say that this was OK to do either.
Title: Temps for the O-320 160hp
Post by: allen on September 10, 2007, 01:20:08 PM
Thanks for the reply. I have also dug through the threads. I have also been on the Lycombing website searching for hard numbers. So far I have not had great luck, but I will keep looking. I am going to order one of the operators handbooks from them this week as well. It's just good to have on hand.
Allen
Title: Temps for the O-320 160hp
Post by: Drew on September 10, 2007, 11:34:27 PM
The Longez owners manual has most of the numbers that you need. The lycoming manual is ok---but will more or less tell you what numbers to not exceed----and I would say don't get close to them.
Take a look at some of the engine monitor sites. They give some pretty good advice on using their monitor---and what temps you should be running. And of course they will give you the disclaimer on checking the manufacturer's manual.
The Sacramento Sky Ranch book (if I remember the name) is a weath of engine information.
There is also a series of books---one of them called Firewall Forward---that are very good. There are several more books in the series---once you find Firewall Forward, you will find the rest. All those books---very very good.
All the lycoming engines run more or less the same.
Takeoff: full power with a carb to get the extra cooling from the extra fuel dump. Use about 120 mph for your climb to cool off the motor. Don't let it exceed 400. Throttle back and level off in the climb if you have too. The engine will quickly "recover," then power back up and resume the climb. Can you get over 400---yes---book says you can go to 435 (memory) continuous---but don't recommend.
Cruise:350 for an EZ is pretty good. I am up around 470 (both Long and Cozy) with no ill effects. Don't exceed 75% power if aggressively leaning. The power charts in the manual are not suitable for the cockpit. You can make your own cheat sheet based on them----but they are difficult to interpret. There is an RV guy on the web (might be rocketboy--but can't remember) who has a spreadsheet for a lycoming that calculates all the values. I use his spreadsheet, (you can change the HP if he has a different size motor), to calculate my cheatsheet that I carry in the cockpit. You will need a MP gauge to do this however. You don't need mp in a 172 because it is fixed pitch---and the test pilots already took mp out of the equation. Your HP for your prop can only be determined from MP, rpm, OAT, and altitude. Most likely if you are in the 2400 to 2500 regime below 8000 ft, you are probably ok no matter what fixed prop you have----unless you have something real crazy. Above 8000ft (std day), your engine can't develop 75% anymore---so you could go full throttle. I normally don't---I usually just max it out at 2700 rpm.
I have now been playing with LOP (I am fuel injected). Works great---fly a little slower----but really sip the gas (3ish gph less---and cyl head temps way down also).
Title: CHT's
Post by: GlennBob on September 11, 2007, 01:05:09 AM
Drew,
Good memory ! !
Direct from the 0-235 and 0-290 series manual, pp 3-5: " For continuous operation cylinder head temperatures should be maintained below 435 degrees F. (224 C). "
I tried to scan the page but the E.Z. site said it was too big.
Glennbob
Title: Temps for the O-320 160hp
Post by: allen on September 11, 2007, 12:05:16 PM
Last set of numbers I got. How do they look to you guys? From what I'm finding on line it looks well within limits that Drew mentions. The probes are bayonet type and located under the motor. This is also a P-51 style intake.
_________________________________________________________ Oat: 95F, density alt:1500 feet, solo at 30gallons of fuel, 25 miles trip
Taxi:
Cht1:280, cht2:284, cht3:299, cht4:287, egt1:998, egt3:1015 airbrake was down
The LOP idea is new to me. I do not have a MP readout. I have read up a bit on LOP but I still do not get how exactly to do it. More reading to be done in that area.
Title: Temps for the O-320 160hp
Post by: Bill James on September 11, 2007, 05:34:29 PM
Allen- A couple of thoughts on changing cooling- -Your cylinder numbers sound pretty good. I flew mine 400 hours over three years before going to downdraft plenums. It was productive time learning the plane and engine, and getting out among the other eze drivers. -My cooling target was to be able to fly wide open at sea level on a 100 degree day. While it is very gratifying to have accomplished that fairly challenging goal, for most of us a better target is just good numbers for normal climb and cruise, which it sounds like you already have. -A parallel target was to play with augmented cooling draw through the cylinders, and of course oil cooling, all good now. Its fun when someone stops by and suggests this or that and I pull an ugly inlet or ramp or tunnel out of the box and say "Like this?" My curosity is pretty well satisfied there, and now some components are being tweaked and minimalized or removed. All this has been done after having flown the plane all over the place for several years, which I hope you have a chance to do. Maybe along the way you will luck into a back seat ride in an operationally well balanced plane where you can observe someone good up front working their cruise climb magic on the way to altitude. Good flying-
Title: Temps for the O-320 160hp
Post by: Drew on September 11, 2007, 11:13:05 PM
Keep the probes on the bayonettes. Get up to 8500 ft and 2700 rpm (or as high of rpm that you can get without exceeding). You can probably go to 2900 rpm (2700 rpm more geared to swinging an aluminum prop)---but why put up with the noise and additional fuel flow? Then lean out the engine. Leaning techniques sort of vary and depends on how balanced your cylinders are. If you lean to peak and then add until you are 100 degrees rich, you should be ok. If you monitor all four pipes (which you are not) then you can tighten up the 100 deg part.
Lean of peak will only work if you are fuel injected---carb engines don't really like it on the "other side" due to the vastly different conditions between the cylinders. Even if you are fuel injected, it may not like it "over there" unless the fuel flow between the cylinders is balanced real well (all cylinders peaking on EGT at the same time---or near the same time).
Your temps are good---but I think you may be down on the power---that's why I say get to 8500 (<75% even at full throttle) and get up to 2700 rpm). BTW, it is nice and cool up there too---and the engine will thank you for it. At those conditions, I would like to see the oil temp a little higher---about 180.
One thing you can do for your winter project is to verify that all of your probes are accurate----and even check your rpm with one of those optical tachs (see if you can borrow one).
Title: Tach check
Post by: GlennBob on September 12, 2007, 12:24:08 AM
Drew and gang,
Here's a FREE way to check your tach and I know it works cause I've done it.
Must be done at night. Taxi near a ramp light or hangar light that is flourescent. I'm not sure if the high press sodium work or not, but with our elect service at 60 cycles, the prop will shadow and " stand still " at any rpm that is a multiple of 60. So . . .1200 rpm, 1800 rpm, 2400 rpm you will see the prop " stopped ". It's a cool way for free to check your tach and it works ! !
Glennbob
Title: Temps for the O-320 160hp
Post by: rglos on September 12, 2007, 11:10:44 AM
While you may be comfortable with the readiings on the bottoms of the cylinders, I found a post indicated that there was as much as a 90 to 100 degree difference between the tops and the bottoms.
I copied it for discussion.
"Well, yesterday I did two things:
1) I installed an aluminum, air deflector in the ram-air box forward of the filter leaving sufficient space between the filter and the deflector to allow air to pressurize all faces of the filter more equally. 2) I moved the sparkplug probe from the upper sparkplug of the #2 cylinder to the lower sparkplug of the #4 cylinder so I could directly measure the delta T top to bottom.
Today, I flew to measure the effects. Here are the happy camper results:
1) Upper probe temperatures dropped by 20 to 30 degrees F. 2) Engine performance improved noticeably 3) There was no switching of relative temperatures between #3 and #4 with a change in throttle position. 4) The delta T measurements showed that the upper TC was indicating - gasp!!- 90 to 100 degrees hotter than the lower TC. Yes, the TCs are calibrated.
I am NOT going to take the easy CHT cooling solution of switching all my probes to the lower cylinders. Besides, if I did that, my cylinders would probably be running TOO COLD ;-). I will stick with my current and known arrangement with the probes on the upper sparkplugs.
The saga continues. That's why the plane is called EXPERIMENTAL."
Marc Borom LEZ N966EZ Ryan Field (KRYN)
That being said, on climb out your #3 cylinder temperature on the top could be as high as 475 degrees.
Rick
Title: Temps for the O-320 160hp
Post by: allen on September 12, 2007, 12:15:05 PM
Well I cannot say that that article gave me any warm and fuzzy feelings :?
There is one aspect to this that has not been addressed fully I feel. The TC relies on heat conduction passing through the various metals of the spark plug and motor into the TC. The TC is also somewhat exposed to the outside environment based on the sheer nature of how it is applied. The bayonet type probes are taking reading from within the cylinder itself. Correct me if I am wrong here, but I am under the impression that the bayonet type probes are more accurate regardless of their location since they are gathering temperatures inside the motor right from the source. Granted the probe wire will be influenced by the outside air, but I doubt that it would be 100 degrees worth of variation.
It would be interesting to see the numbers for a motor with bayonets on the bottom and TC’s on the top. I would postulate that they would not be that different on an up-draft style Long-Ez. However, I have never been accused of being terribly bright.
Thoughts?
Title: Temps for the O-320 160hp
Post by: rglos on September 12, 2007, 02:07:11 PM
Very good questions Allen. I hope someone address this. My engine does not have bayonet access on the top so I have no choice.
One thought: If the bayonets are on the inside closer to the heat source the spark plug type should theoritically be cooler. (because they are closer to the cooling source) That is if they are mounted on the bottom side as well.
What would the temperature differential be between a Bayonet on the bottom and a spark plug type on the top?
I just finished reading the Schubert/Hertzler PP presentation on this subject and it has given me many things to try after the engine has broken in. I need a good baseline to work from.
In the meantime I'm just going to throttle back to keep the #4 jug below 425 degrees. Incidentally a friend in the Hounduras recently purchased his Long and is running nearly the same set up as you. (O-320, P 51 scoop) I think he is running nearly the same temperatures as you with probes on the bottom.
Contact him at saybeengineering@hughes.net
Title: Temps for the O-320 160hp
Post by: Bill James on September 12, 2007, 02:50:21 PM
On sender location, over the years i ran washer senders on the tops and bottoms of cylinders at the same time. I also tried putting bayonet senders on the bottoms, which showed the same as the adjacent washer sender. The hotter sides indicated 'about' 60 degrees higher. With dd cooling I run the senders on bottom for worst case readings. It is interesting to record the differing temps in climb versus cruise versus wide open on the deck. After a while we can maybe detect which flight regime needs a little help and affect a benefit at that point without screwing up the other conditions too much. I agree with Terry Schubert's Oshkosh cooling forum comment that different pilots get different performance and readings in the same airplane because of technique. Hopefully we all get better. At Jackpot i could outrun Beagle matched side by side but he always beat me because of his 20+ years of smarts. I'll get him next time.
Title: Temps for the O-320 160hp
Post by: Drew on September 12, 2007, 11:20:29 PM
There is a discussion (I think the CPs) where someone had TCs on all spark plugs and the bayonettes with updraft cooling. From there he made certain conclusions.
I have come to 2 separate conclusions: 1. Running both of my engines (Long--downdraft; Cozy updraft----both with bayonettes) within the parameters that I listed in an above post---never was bad for me. But to really know for sure----you have to start with a fresh engine and see how long you go until overhaul.---so maybe that one is not a really good conclusion 2. I challange anybody that you really don't know what you have unless you are running downdraft cooling with TC in the bayonette boss. The lycoming numbers are based on this.
There will be a delta temp from one side of the cylinder to the other---these machines are aircooled. I would also assume (but don't know) that with engine sitting still on a test stand that the bottom of the cylinder would be hotter due to the proximity of the exhaust valve/port/pipe.
Title: Temps for the O-320 160hp
Post by: allen on September 13, 2007, 01:22:37 PM
Good points guys. Certainly food for thought.
On my next flight I’ll head up to 8.5 and run at 2700rpm and see what those numbers look like. Honestly, I have not run engine at that high of an RPM in the past intentionally. While flying the FBO Cherokee’s with the O-320 I was cautioned to never run above 2500 rpm or it will harm the motor. My flight instructor would always walk it back to 2400rpm. I just got in the habit of running at 2400rpm I guess. Anyway, I’ll run it up and see the numbers.
Frankly guys, I hate to admit it, but I’m scared that I’m going to “hurt” the plane. Again it harkens back to my tin can days. Anything more than a couple G’s and I panic that the wings will rip off. After years of following these planes and reading about just how strong they are, I still worry a bit. I guess that’s where I get the fear about the causing harm to the motor by spinning it too tight. It is reassuring to hear from you guys that the temps are good. That was becoming a real fear for me.
With regards to exhaust temps under the cowl I have a concern. The right side pipe has been wrapped in fiberglass to stop damage to the paint. The left one is still unwrapped and the paint shows signs of heat damage. I would like to wrap the left pipe to save the cowl. While at it, I would like to put in some felt style heat shielding that Berkut13 has on his website. This would theoretically solve two problems: it would save the paint and cowl from heat relate damage, and it would contain any heat radiating from the pipes into the compartment. Anyone out there doing this already?
Thanks for the help everyone. Still leaning, and having a blast doing it! 8)
Title: Temps for the O-320 160hp
Post by: Drew on September 14, 2007, 12:01:12 AM
In the CPs there is a discussion by either Burt, Dick, or Mike Mellville on running at "high" rpm---like 2700 to 2900 rpm. I encourage you to read through that----you can get the text online. In your "tin can" airplane, you are swinging a much heavier mass (aluminum propeller). Additionally, some engine/aluminum propeller combinations have a resonant frequency (certain rpm to avoid) that is destructive.
As I said before, full throttle (non turbo/non supercharger/non altitude compensating engine) is approx 75% at 8000 ft---and drops off from there. Ideally when you are trying to match your fixed pitch prop to your aircraft, here is what you are trying to do (and of course each one of these things is fighting with you---so you have to compromize): --generate enough static rpm on the ground to be safe (can't remember what this number is----but probably around 2200 to 2300 rpm). If you can't generate the rpm, then you need a prop with less bite (assuming a properly running engine). --generate the rpm you would like to cruise at---at your "normal" cruising altitude--at full throttle (assuming your normal cruise altitude is above 8000ft). If you have too much rpm up here---then you need more bite.
As you can see, if you need more bite at altitude, but can't generate the required rpm on deck, you are going to have to compromize---you may need longer runways with the bigger bite-----or accept a little more higher rpm at altitude.
I typically run between 2500 and 2700 rpm---depending on noise, how fast I am trying to get somewhere, how hot the engine is running, etc
An interesting note on LOP----engine has a different sound to it in this regime.
Title: Temps for the O-320 160 HP
Post by: Bruce Hughes on September 14, 2007, 12:41:16 AM
AGGGGH. :shock:
NEVER, NEVER, NEVER consider wrapping an exhaust pipe!
You need a metal (SS?) shield to protect the cowling.
I am NOT an expert; I'll just tell you what happened to me.
I read the info in Aircraft Spruce and Specialty's catalog. Bought that lie hook, line, and sinker. Bought the wrap (now another type is in the catalog but the idea is the same) and installed it.
After some time (I was just doing taxis at the time) I noticed that the exhaust nuts were rusting severely. :shock:
Those were the exhaust manifold nuts (STD1410 or 1411, I forgot which size) specified for Lycoming engines.
I tried to take the nuts off. Got 6 off with some difficulty. The last 2 were hopeless. Rust crumbling off the outside. Of course, the high temperature of the exhaust gas was held in the pipe and reflected back to the flange and nuts.
I filed the nuts down on 2 sides until I could get a 5/16" wrench on the nut. Turned it 60 degrees. Filed again. Turned it 60 degrees. Turned it and filed the 3rd set. This filing took hours. :(
I took the wrap off and bought more nuts. Never believe what a manufacturer's label says; ask someone who has been there.
Bruce Hughes :D
Title: Temps for the O-320 160 hp
Post by: Bruce Hughes on September 14, 2007, 10:17:34 AM
You might try calling Lycoming. :idea:
I think the tech rep will tell you that a major cause of engine failure is overheating of the exhaust valves. :(
Bruce Hughes
Title: Temps for the O-320 160hp
Post by: allen on September 14, 2007, 11:45:32 AM
Went up last night to get some numbers and here they are. This is with an O-320 swinging a Great American 62x72 and with 25 gallons of fuel on board at 8.5k.
Outside air temp on the ground was reported as 74F, winds calm. Static RPM run-up was up to 2500 with no problems. On takeoff I noticed that at rotation speed I was showing 2650rpm.
Ground taxi was with aggressive leaning and running at 800-1000 rpm and brake down. Temps stayed nice and low.
Once at altitude I made a few long (60-80nm) flights to allow the motor to settle in and determine the winds up there. My 396 was reporting winds at altitude as 5kts. With that in mind I made 2 circuits with the winds abeam, and two with winds head on and dead astern.
Once settled:
RPM: 2660 firewalled and leaned Grnd Spd: 173kts average, (as reported by my Garmin-396 post flight) Oil: 197 CHT 1: 315 CHT 2: 303 CHT 3: 370 CHT 4: 347
EGT 1: 1238 EGT 2: 1374
Bruce,
Thanks for the information. I have sent an email to Lycoming for clarification. Once I hear back I’ll post it here.
Allen
Title: Temps for the O-320 160hp
Post by: Drew on September 15, 2007, 02:50:09 AM
What did you use for leaning technique?
Do you have a fuel flow gauge?
Your engine is running just fine as it is---actually it is fairly cool. The oil temp is about 17 degrees higher than ideal---but is ok.
If you want, you can work at balancing the airflow around the cylinders. From what I see (brainfart here---#1 is the one closest to the prop?), your cylinders by the firewall are the hottest---which is normal---but you can fix. But before you do anything---make sure that the TCs are correct.
There is a lot of documentation in both the CPs and CSA newsletters that talks about balancing. One has to do with the baffles that go around the cylinders. Basically, the air will enter into the opening of the baffles on the bottom of the cylinders. You can remake/rebend the baffles accordingly to make the entry area smaller for the cooler cylinders and larger for the hotter cylinders. Obviously, this will be an iterative approach. The other thing to do is to build fiberglass ramps to divert air to the front cylinders. In the Cozy, you build a rather large ramp to make sure the air gets to the front cylinders---and if you do it right (ramp big enough), you will hopefully overcool the front cylinders. Then you start cutting down pieces of the left and right side of the ramp until the cylinders are even. Don't cut too much at a time---much easier to cut ramp than to add ramp!
By the way, your engine rpm on the roll is always higher than static. The windmill effect relieves some of the load on the prop. I would say that you have a good prop engine match.
Title: Temps for the O-320 160hp
Post by: allen on September 16, 2007, 11:20:10 PM
Drew,
No fuel flow gauge on board. I have been looking at swapping in one of the multiple function gauges that has fuel flow as one if its functions. One plane that I looked at had a gizmo that showed engine power in a percentile of max output. I found it to be helpful when trimming out at cruise.
In regards to leaning out the motor at altitude I have been doing some trial and error. Since LOP is not an option for a carbureted motor I have been trying to find the sweet spot.
Today I went for a scenic flight. It was a bit cool today. ATIS reported 70F and calm winds. On the ground I leaned until the motor ran rough, then increased the mixture until it ran smooth again and stopped. Up at 4.5k I trimmed out and followed your recommendation and cruised at a higher RPM than I usually do. This flight I kept it under 2700 and tried to keep it about 2650-ish. The GPS showed calm winds at altitude and a ground speed of 165kts.
After I was established and the temps looked good I started to play with leaning out. I leaned the motor while watching the CHT’s and EGT’s. One thing I noticed was that RPM would increase by about 10-15 while the temps climbed about 25 degrees. The motor also ran smoother. I guessed this to be the sweet spot. The temps all behaved.
After a while I landed at Martinsville to gas up and watch the locals. On my walk around I noticed that I had a considerable amount of black soot on the prop. Interestingly enough, the soot buildup was almost entirely on one blade. Not too sure how that happened. More to the point, I’d like to know why I had all this soot in the first place!
Before I took off for Roanoke I cleaned off the soot to see if I could recreate the event. Once in Roanoke I looked at the prop again and although I had some soot again, it was not anywhere near the amount I noticed in Martinsville.
Since I had been fairly low today I made a real effort to not lean to aggressively; only to the point that the EGT/CHT increased, then increased the mixture until I notices the EGT/CHT start to decline again. Once the temperatures began to cool down again I stopped enriching the mixture.
On a side note I have installed my onboard camera. It worked great! Initially I was worried that the vibration would be a problem, but to my surprise the video was perfectly clear. The setup is very similar to the one Jason Redman is running in his Berkut.
Where can I find the CP’s and CSA letters? Who do I contact about joining the CSA? I have joined the EAA and will be joining the local EAA chapter as soon as I can make a meeting. (They majority of the local chapter are retired so their meetings tend to be at time when I am at work.)
Stay safe. See you when you get back.
Allen
Title: Temps for the O-320
Post by: Bruce Hughes on September 17, 2007, 12:26:08 AM
Hi Allen
The CSA information that you need is in this website. On the Homepage, click at the 5th item on the left margin.
Terry has old issues; I believe that the price is the same as a current subscription ($30 for 1 year including the directory). I think you can buy individual issues.
A little further down is the Canard Pusher info. It is no longer published so that is all the info we will get.
Bruce Hughes :D
Title: Temps for the O-320 160hp
Post by: Drew on September 17, 2007, 06:30:15 AM
Without knowing what your %power is---I would stay below 2500 rpm in cruise unless you are above 8K ft. Once you figure out what 75% is, then go ahead and throttle up.
What do your pipes look like? Ideally, you want them to look sort of tan looking on the inside. If they are black, you are either running too rich or you could have a problem with one of the cylinders on that side----most likely too rich.
Go search the web on leaning technique--many people do many things---and everyone's setup varies. I monitor all four cylinder EGTs. I lean to peak (Dynon Engine monitor makes this real easy----but your conditions need to be real steady---steady speed and altitude). I then enrich about 75 to 100 deg EGT on the first cylinder to peak (there are discusions on running at peak, 25, 50, 100, 200 ROP). I also look at the value of the hottest EGT---if too hot, I enrich some more. Download the instructions from several of the engine manufacturers such as JPI or EI----great discussions on things to look for).
Another technique is to lean until rough, then push it back in until smooth.
The way to tell good performance of your airplane is to record TAS---either with a TAS gauge----or calculate when you get back on the ground (grab the OAT at altitude---or look it up the nearest weather balloon on line).
How are you getting winds at altitude? Does your GPS have a feed from your pitot-static system? I get winds from my BM Lite---do you have something similar?
Title: Temps for the O-320 160hp
Post by: allen on September 18, 2007, 02:31:01 PM
Drew,
Sorry for the delay. To answer yor question though the pipes were rather black and not the tan you described. This was something new so I attribute it to my failed leaning temps. The method I used was to lean until rough, then increase until smooth again. Guess I need some practice. Still, what would make the soot build up so significantly on only one blade? A harmonic anomaly maybe.
This plane does not have an OAT gauge so I would have to best guess after the fact. One thing I have learned so far is that these planes love to be up high so I suspect I will spend most of my time above 8k. I’ll do some more reading on leaning methods. I’m at a conference in San Antonio until the 23rd, but when I get back I may be making a flight to Montgomery Alabama the following weekend. I’ll plan that flight at p around 10k or so depending on the weather.
I went to XM radio to see if I could find where they get their winds aloft data. They are mum as to the source. From what I could gather from previous flights it seemed to be more accurate than I could get. This 396 is very handy. It even puts up TFR’s as they change. According to the website they quarry that data right from the FAA website. Initially I was really hesitant to buy this thing but I have to say, it has got to be one of the best tools I have in my VFR arsenal so far. Great gadget.
Title: Temps for the O-320 160hp
Post by: Jack on September 18, 2007, 08:33:35 PM
Quote from: allen
In regards to leaning out the motor at altitude I have been doing some trial and error. Since LOP is not an option for a carbureted motor n
On a really big recip like a R-2800 with a carb we leaned to LOP as SOP. Tis an old wives tale about running LOP. If you have the gauges and touch use it.
Lycoming long ago highly recommended using LOP on their motors. It kinda of fell by the wayside.
Iraqijack
Title: Temps for the O-320 160hp
Post by: Drew on September 18, 2007, 10:55:58 PM
My guess is that Lycoming lost the secret sauce somewhere---and now their carb motors won't run LOP.
With fuel injection, you can get the cylinders to peak near enough to one another to run LOP.
But---you can always try to run LOP with a carb motor. The motor will tell you if it does not like it there.
Jack---when you coming up to Speicher next?!
Title: Temps for the O-320 160hp
Post by: Bill James on September 21, 2007, 10:51:56 AM
Allen- You mentioned leaning in your thread. For the last couple of years I have flown what could be called extreme LOP. My VariEze can be flown with the throttle full open and the RPM reduced with mixture, down to around 2000 RPM. Am still developing the efficiency potential. With the previous stock oil sump induction the lowest comfortable RPM with wide open throttle was about 2350, about normal I hear. I am not at all suggesting anyone needs to cruise at 2000 RPM, but rather per your comment, am offering some elemental thoughts on leaning during this experience. You proabably have more info than you can use. The simple intent is to mention some personal experience and sources. Satisfying curiosity and resolving the unknowns and concerns, they can be shelved and we can go fly.
Because of length, it is posted at http://www.ezchronicles.com/blogger.html
Good flying
Title: Temps for the O-320 160hp
Post by: Jack on September 23, 2007, 07:28:34 AM
Quote from: Drew
My guess is that Lycoming lost the secret sauce somewhere---and now their carb motors won't run LOP.
?!
It's in my database at home on leaning LOP with the Lycs. Have to go back to the 70s or so for their actual procedures. Article I read the pilot used some serious gauges and finally resorted to leaning back to a slight rise in RPM and then drop it a tad. Which was basically what we used in R-2800s with the BMEP or power gauge being utilized.
Lately only been running to Biap and to the West. Right through freaking Fallujah and hauling ass in that pissant city. If you hit the big city or the snake drop me an email. I could be running either one of them. Been pushing us hard lately.
Next month I head back for my R&R for a couple of weeks.
Cheers;
Jack
Title: Temps for the O-320 160hp
Post by: Drew on September 24, 2007, 07:49:13 AM
Jack, I had heard of running LOP with carb'd Lycomings but did not think they would run there anymore due to the cylinder "not flying very close in formation." However, you do have Bill James and others doing it---but not with stock Lycomings---they have screwed around with induction tube lengths and whatnot to solve the problem.
All of my wandering around Iraq will be limited to the North (MND-N) since that is where all my trucks are based. Don't drive too fast----if you can see, you can avoid. After R&R are you going to be doing any runs up north?
Title: Temps for the O-320 160hp
Post by: LongEZDaveA on September 25, 2007, 08:07:03 PM
Quote from: Drew
Lean of peak will only work if you are fuel injected---carb engines don't really like it on the "other side" due to the vastly different conditions between the cylinders. Even if you are fuel injected, it may not like it "over there" unless the fuel flow between the cylinders is balanced real well (all cylinders peaking on EGT at the same time---or near the same time).
Drew - I agree with your post except this part. My Long EZ has a O-235 with a carb and does well very lean of peak. I only go LOP when full throttle and less than 65% power. If I try to throttle back it starts running rough. A big point is that I also have a Light Speed EI. I think the multi spark is important LOP.
Title: Temps for the O-320 160hp
Post by: Drew on September 26, 2007, 12:40:47 AM
Can you get it to work at 75%?
To me, it appears that Lycomings modified with either fuel injection and/or elect ignition or balancing the intake tubes will get you to LOP. But without modification, it may be difficult to get there.
I had a Hal Hunt ram air scoop for my carb on my Longez. I had seen people put a deflector right in front of the filter to get the air to be a little more uniform going into the carb instead of piling up on the back side of the carb. I wonder if this would have worked instead of modifying intake tubes?
With my Cozy (fuel injection and elect ign), I run at 75% and fairly LOP. All CHT temps were way down---sacrifice some top speed---but EGTs were fairly hot.
Title: Temps for the O-320 160hp
Post by: LongEZDaveA on September 26, 2007, 12:47:54 PM
It may just be ignorance, but I have been afraid to try LOP at 75%. I have 9.7:1 pistons and have heard that it is not advisable to operate LOP with that high of compression. I don't really know, therefore I haven't tried it.
I have the Hal Hunt ram air box on mine and have always used the foam filter that came with it. Some say the foam filter is more restrictive (again I don't know for sure) and this could have lead to more even distribution/flow going into the carb. I'll see when I fly again now that I have changed to a K&N filter.
I do know that when I would go way LOP, that the CHTs and EGTs would go down a lot. That was the only way I could get my engine cool enough for cruise, or so I thought. I am in the middle of a rebuild and have found a large error on my uMonitor on the CHTs. I had to add a resistor to the board to callibrate the CHTs. I can't wait to get it in the air again and see what kind of continuous cruise speed I can get with acceptable temps now that I have the CHTs callibrated to a RTD.
Title: Temps for the O-320 160hp
Post by: Drew on September 26, 2007, 11:03:10 PM
If you have a source for the 65% power and LOP thing, please post. I am having a hard time trying to figure out how 75% ROP with higher temps is better than 75% LOP at lower temps.
Title: Temps for the O-320 160hp
Post by: LongEZDaveA on September 27, 2007, 01:18:45 PM
I'm terribly "memmory challenged" and don't recal the source. Seems to me there is an issue with the higher compression and lean mixtures tending to cause detonation or pre-ignition or.....
I can't disagree with you about it being tough to figure out how 75% ROP with higher temps is better than 75% LOP at lower temps. I think it is more an issue of higher cylinder pressures caused by the high compression and that higher cylinder pressure in combination with a lean mixture make the flame front progress more rapidly. I don't know, but I'll try to look it up when I can.
Title: Temps for the O-320 160hp
Post by: Jack on October 03, 2007, 05:54:15 AM
Quote from: LongEZDaveA
more an issue of higher cylinder pressures caused by the high compression and that higher cylinder pressure in combination with a lean mixture make the flame front progress more rapidly. I don't know, but I'll try to look it up when I can.
NACA the forerunner of NASA has an online database stretching back to 1917 or so. Do a search and pull up the database. Most of these issues were addressed decades ago. Another point as you fly higher your losing power due to less atmosphere. So unless your running a turbo or supercharger you won't have sea level power in the teens.
When I was running R-2800s we had a two speed supercharger and went to high blower somewhere before 14,000 feet. It also sucked up 50 BHP of power to turn the puppy.
Have to know your motor and it's sweet spot. Freaking 2800s had a serious section on running the motor for long range cruise and I usually ran it right at 2100 RPMs because the engine felt good and less vibrations.
Jack
Title: Temps for the O-320 160hp
Post by: Drew on October 04, 2007, 04:15:22 AM
Jack, I'll be moving out of the "country" (Speicher) and into the "big city" (Victory).
Title: Temps for the O-320 160hp
Post by: allen on October 04, 2007, 10:42:00 AM
Drew,
The wife (Kris) will be in your neck of the woods as I understand it. She may look you up and say hello at some point. If a hot looking redhead shows up at your office don't be alarmed. :wink:
Allen
Title: Temps for the O-320 160hp
Post by: Jack on October 05, 2007, 02:06:34 AM
Quote from: Drew
Jack, I'll be moving out of the "country" (Speicher) and into the "big city" (Victory).
Sent you an email several days ago. Am actually stuck in the big city right now due to vehicle breakdowns. Pretty damn funny and we had one helluva of a traffic jam. Dunno when you are coming in, am stuck over by the De Fleury DFAC. Which nearby has the best deals on DVDs and software.
If you have the NACA website can you post it here? I got it somewhere but I avoid carrying my lap on the road since we have been taking some hard hits lately and Uncle doesn't pay for squat you lose.
Drop me an email with your new addy and or phone. I usually hit Liberty a tad and right now am looking for a damn shower.
One item about leaning, have to know your motor. I had an older bird with an O-200 and just being off a quarter inch or so on the mixture control was enough to screw it up. I knew it was off by the IAS.
With the winter upon us. You might try using carb heat on the cold days for a better fuel burn. I run about 15C and then lean it out.
Hey it's an X class bird you can try damn near anything.
Jack
Title: Temps for the O-320 160hp
Post by: Drew on October 05, 2007, 03:17:12 AM
Jack and Allen, I'll let you know my address when I get down there (should helo down between the 20th and 25th). I think that I am working at Victory and living in Liberty.
Allen, I'll take a picture of Kris and send.
Title: Temps for the O-320 160hp
Post by: allen on October 05, 2007, 08:01:10 AM
Drew,
That would be much appreciated. :wink:
Jack,
Thanks for the info. I’m still toying around with the settings a bit. Over the last few weeks I have been looking at changing a couple of the gauges in the panel to free up some realestate so I can put in some MF gauges. I would like to have something that shows real time fuel flow and maybe even have calculator for fuel remaining. I would also like to add a MP gauge. The panel I have now works great, but the bug has bitten and I feel the need to tinker and tweak. (Damn you Burt!)
You guys be safe. Either of you need anything I am more than happy to help out any way I can. Just let me know.
Allen
Title: Temps for the O-320 160hp
Post by: Jack on October 05, 2007, 10:22:37 AM
Quote from: Drew
Jack and Allen, I'll let you know my address when I get down there (should helo down between the 20th and 25th). I think that I am working at Victory and living in Liberty.
.
Ahh so. Sounds right. Just found out am stuck another night here. I might be in Biap on the 21st or so if they don't fly me direct out to DXB for my R&R.
You wanna hit the DVD and software store by ECP 4. Picked up Vista and Office 07 for 3 bucks a pop.
You hit Victory let me know. Probably have a run into it sooner or later. I can point you to the good deals. Might be leaving the country at the right time. Lots of message traffic on it lately.
Thanks Allen am pretty well set up. After 31 months over here I have accumulated a tad too much.
One point about running fuel flow, it does slow down your fuel flow a tad. Might double check to see how much. On a Vari with gravity feed fuel flow meter is a bad idea.
Cheers;
Jack
Title: Temps for the O-320 160hp
Post by: allen on October 05, 2007, 11:17:48 AM
Jack,
31 months?! Why don’t you come on home and let some others have a chance to go over and play. Stop hogging the war!
I can sympathize to a degree. I did 3 tours in the sand box myself, but none for that duration. (93’, 95’, 97’) Somalia was the most hostile tour for me, but that was a relatively short lived exposure. Nothing like what you are seeing on the ground there. The gulf was pretty well behaved during the time frame I was there. My wife is over there now. I tried to prepare her for the heat, but how can you really ever explain that kind of heat to somebody. Or exactly what a camel spider is. (Don’t think she has had the pleasure of seeing one yet.)
Reading on some of the manufacturer’s websites about fuel flow gauges and how they work. The little mad scientist in me wondered if it impeded fuel flow. With a mechanical and electric fuel pump I cannot imagine that the fuel flow would be obstructed measurably. Still more reading to be done on this. I sincerely doubt that I will be doing any kind of modifications to the plane for the first year or so. That doesn’t mean I cannot compile a dream sheet though.
Get yourselves home safe guys. Plan on making Rough River next year!