Would I have survived?

T

teson1

Charter Member 2014
Ok, I pushed the engine (or the sim model?) of the L-1049G Connie way beyond typical realistic operating conditions for the Evita event... :kilroy:

In particular I flew with much leaner mixture than recommended:
- approx. 30-40% lean (recommended 10% lean with low blower), and
- higher MAP than recommended: 48-49 psi (recommended not to exceed 43 psi with low blower as per the handling notes http://www.flightsim.com/file.php?cm=SEARCH1&fsec=0&fname=L1049G.ZIP).
See other parameters below.
These operating parameters resulted in -30% fuel consumption compared to AutoLean mixture setting.

After reading a lot on realistic flying during the event I am having second thoughts.
I guess the more one knows on how and why the real planes are operated the way they do, the less fun there is to operate the sim game-style...

Now, I wonder about the following:
Is it in principle possible to fly the way I have with the real plane?
Would I (and the plane) have survived the trip?:engel016:

+ What would have happened to the engines?
- Would the engines have worked at all with very lean mixture?
- Would the plane have arrived at all at a leg's destination or would the engines likely have failed in flight?
- Would the engines (and other parts) have to be changed after each leg?

+ Would the real plane have behaved the same way regarding fuel consumption/speed, or is it a quirk in FS that consumption decreases so much with very lean mixture?

I mean would it have been possible that a participant to a real-world race would have flown my way, and arrived, scoring similarly? Even if this would have required installing a new set of engines at every airport and any spare part needed, unlimited money, was willing to take risks - somebody who would _really_ like to win... (who, me? Hehe... :d)

I would appreciate your insight. Sim or game flying?

Thanks,
Gunter

******

Below are the parameters with best speed/fuel efficiency determined by test cruise flying.

Plane: Lockheed L-1049 Super G - Jahn et al - flightsim - l1049g.zip with update
http://www.flightsim.com/file.php?cm=SEARCH1&fsec=0&fname=L1049G.ZIP

The parameters were optimised to provide the best "score" (speed/fuel consumption) in the frame of the Evita race rules:
Total score is flight time + 0.3 hr for each 1000 lbs of fuel consumed.

Main observation was that speed (power) for a given altitude is determined by a given set of RPM and BMEP (which is realistic for this type of engines as far as I understand).
Fuel consumption was the lower the leaner the mixture (the higher the MAP to achieve a given BMEP).
So best score was obtained with maximum permissible MAP (49 psi, end of green arc, for the model, as higher MAP may have resulted in failure of the modeled engine AFAIK).

Altitude = 10000 - 12000 ft (actually, cruising higher resulted in lower scores. With critical altitude = 10500 ft, MAP available was below 49 psi, i.e. needing a richer mixture and higher fuel consumption)
Low blower
2500 RPM (green arc)
BMEP = 170-180 psi
MAP = 48-49 psi (end of green arc)
Mixture = very lean (14-16%)
The mixture was leaned so far that with a MAP of 48-49 psi (end of green arc), BMEP was 170 - 180 psi.

This resulted in a TAS of 260 KTAS (approx 220 KIAS) and
fuel flow of 610 PPH/engine (2440 pph).

With AutoLean Mixture setting for comparison:
Mixture = AL
MAP = 34 psi
FF = 960 pph/engine
All other parameters (RPM,BMEP,TAS) same.
Fuel consumption was reduced by 30% by leaning the mixture.

Btw, the Composite Cruise Control Chart of the real plane, included with the handling notes gives the following parameters for cruise at
12000 ft
115000 lbs
220 KIAS
high blower (no chart for low blower):

2500 RPM
BMEP 180 psi
FF 840 pph/engine (3400 pph)
 
There is a strong possibility you would have survived. :engel016:

If once you blew the first engine you backed off the throttle and played it safe you could have landed safely.

If you would have pushed the three remaining engines until failure No you would have been Toast. :173go1:

For the Record McHales Airlines ran the Northstar / Argonaut at the published numbers in the referance pages. :wavey:
 
We had conceived this event to fly the propliners at published specs. Unfortunately not everyone did this. (Gunter, I'm not picking on you directly.) It was a great turnout and kudos to those who completed the race but in the end it was unfair to those who ran their entries within normal real world numbers.

I hope sometime in the near future we will have a Duenna type program that can monitor engine map & rpm for these types of events. Maybe even check to see if you dive down to the ground exceeding fpm for that particular aircraft. You would then be flagged with errors accordingly. My opinion of course. I would also like to see the RTWR race be flown more realistic someday instead of 90 minutes of firewalling your late war fighter.
 
In general, it's possible to run 'super-lean' mixtures on some engines. Long-range patrol missions during and after WWII proved the theories (notably Catalina flights of up to 24 hours) but the precise numbers were initially found by trial and error. A P&W engineer could probably pull a file to give absolute numbers for a given engine/airframe but I'm not sure FS, with it's limited model would prove too realistic. Some basic information may be found here:
http://www.lycoming.com/support/publications/service-instructions/pdfs/SI1094D.pdf

On the subject of altitudes, FSRTWR history shows that in non-supercharged engines the efficiency loss of operating slightly above "critical altitude" - lower power and related loss of speed - is compensated for by better winds aloft (for longer periods). Tossing two-stage blowers into the mix raises new questions, but the 1049 was designed to operate in the range of 17,000' to FL230 on long flights.

Advanced system modelling like that in the A2A B377 brings out some of the other issues (cooling, etc.) but the basic FS model is limited. In most cases I'd say that the published numbers have been tested to be the optimum (if taken from the real world stats) to balance performance with engine life and costs (fuel vs flight times vs maintenance).

Rob
 
Over Lean mixture will push the CHT up up up, and you will cook the engine. An accepted practice is to lean out the mixture untill you show EGT(if you have one) rise, then nudge it back towards rich. As altitude increases, air density drops, so the mixture needs to be leaned out.Over rich mixtures give lower temps but foul the sparking plugs. One can monkey with the mixture some from the book settings, but the mixture/MAP/RPM/Fuel flow graph has been arrived at by many,many years of trial and error and hard won experience. I have read several accounts of P-51 drivers getting home with cooling systems shot out by running full rich,and stroking the Kholer pump(manual primer) every 4-5 seconds to over rich the engine, keeping the temps just under the red line.It would run like crap, as the plugs fowled, so you quit pumping for a few moments to let the temps climb and burn the lead off the plugs. Don Gentle wrote that, after 2 hours or so of contiuous pumping nursing his Mustang back with a shot up rad, that he had worn the thumb out of his glove, and then wore the hide off his thumb down to the bone, the cockpit looking as if a hog was slaughtered in it, but that was preferable to being a POW.
 
Dave, kudos for the excellent performance! Mc Hales is the real winner in this event. But that was clear from the beginning, in view of McHale's mileage.

Moses,
I take your point, and maybe I have not read the rules sufficiently in detail, mea culpa. :173go1:
A big part of the interest in the racing for me is to squeeze the best performance out of the plane, find a sweet spot with best performance.
Now, another big part is keeping everything as realistic as possible.
Seems I have veered way outside of the realistic envelope here.

Blame this on my lack of knowledge on what a real plane can stand and what not. But learned a lot (and that's another part of what I love about FS!).
Here's my trophy back! :medals:
Now I'll crawl back into my hole. :toilet: :d

srg, now that is very interesting information!
So it seems I have shamelessly exploited the limits of FS.
Seems at least the engine should run rough with very lean mixture. Tsstssstsss, seems we need a new sim... :monkies:
 
Gunter- Please keep your trophy!:medals: I'm just a bit grumpy at times about sim-style balls out racing vs real world flying.

We had encouraged everyone to fly by the numbers but it was not a rule. This race was a good measuring stick for future events. Especially with the payload management.

Hopefully everyone had fun with it one way or another. :)
 
Here's an interesting series carried on AvWeb-
Pelican's Perch #63:
Where Should I Run My Engine?
http://www.avweb.com/news/pelican/182179-1.html
http://www.avweb.com/news/pelican/182176-1.html
http://www.avweb.com/news/pelican/182583-1.html
It's involved, sometimes technical and rather lengthy but worth a read.
(note: it's written for injected engines and there are differrences for engines with carbs.)

One thing to consider is that not all models have fully functional CHT gauges etc. so it's hard to follow complete procedures.

As for 'exploiting' the limits, the way I see it, in the interest of not "over-legislating" the event, the committee didn't specify every parameter so there naturally would be some accidental or intentional fudging. A lot of that was balanced by the calculations used. To be as precise as possible would also require a sim that enabled all the functions of a r/w aircraft and we don't have that, nor do we have perfectly modeled aircraft. For example, are the #s for the NorthStar perfect? We have to depend on the info published and what we could test.

In the McHale case, we tested almost all the listed aircraft and looked at the rules. The significant advantage of operating at FL250 with strong westerlies and the tested fuel burn gave us an indication that it would be significantly ahead of most of the fleet that had to fly low, so we purchased the surplus NoisyStars and set off. We also had a set of fuel consumption tables (from testing) that gave us predicted loads to be used based on the forecast, or observed winds and which were within about 10% of what we got on the legs. Sure it was a fair bit of work, but that's what it takes to run a successful airline :icon_lol:. We also tested performance "beyond the book" and found there was little to be gained in the case of the NorthStar and risks attached. (Yea Jens!)

Rob
 
srgalahad said:
In the McHale case, we tested almost all the listed aircraft
Rob
Click to expand...

Time wise I am inclined to believe we had more time invested in testing and preperation for the event than we did flying the Race.

:icon_lol:

I flew each plane to each set of published numbers "High Cruise" "Fast Cruise" and "Economy Cruise @ varing altitudes to test the speed and fuel consumption of each aircraft. That is excluding the A2A 377 which I do not have.

That alone took days and was likely what fried my video card. :pop4:

Then once we decided which aircraft to use we needed our own Paints. :icon_lol: There goes another week of work.

Now the rules come out and we find out about this %^#%#&^% Payload Bonus. Which could have been the great fuel efficiency equalizer.
 
Racing outside the numbers

You can count me in the group with Teson that squeezes every ounce of performance out of the flight model without much regard for what the actual aircraft could perform. I simply took the data that was provided by the committee, downloaded the various models and tested to see which gives the best performance for the desired route operating under the rules in place. This is what I do for the RTWR so it seemed applicable here, although apparently some may see it a bit differently. However if there were an unenforceable rule to fly to certain engine parameters, much like the no GPS rule, I would honor it of course.

Sorry if I frustrated anyone with my interpretation of the rules or perceived fudging. I had fun pushing my aircraft to the limit and navigating around South America once again. :jump:
 
every ounce of performance out of the flight model without much regard for what the actual aircraft could perform
Click to expand...
That whole issue is what frustrates some of us (or all of us some of the time?) - the flight models are not totally realistic and enable us to get away with all sorts of things. From my discussions with a few builders and FDE guys it seems to stem from having to make compromises to fit the MSFS game engine, unavailable data or sometimes a lack of time/patience/knowledge of how to bully MSFS into doing it "right". In other cases the FDE is simply wrong but thousands of adoring fans would be up in arms if performance or flight characteristics were too "real" and the model didn't perform like the PR guys said it should -- I'll put the Shockwave P-51 in that list. Others, like Gnoopey (P-47) and C. Knoell (F4F-4) have worked hard to model to the real world.

As far as the airliners we ran, they mostly were close to proper numbers for speed/fuel overall, but some do better than others at emulating not 'airline style' flying, but accurate stress or climb/descent values. One example is the DC-4/6 emergency airbrake setup (which was real) that required lowering the main gear as otherwise the airplane would overspeed/overstress in anything over about a 1500 fpm descent. Some models just fudge it --- which is then available for us to fly it that way.

In the Evita we also didn't have a chief pilot looking over our shoulder, ready to chastise us - or fire us- for overly aggressive turns, descents or 'hot' climbs that are verboten in something like an airline operation. We all know that to go to that level would deter some of the entrants who've never learned or practiced flying to those parameters - and drive the organizers nuts.

As we do more testing against real-world specs for our various events some of these 'freaks' become known but it's difficult to rule some of them out as there is no alternative model available. That's why I really like Jens' NorthStar... trying to fly it 'beyond the book' just didn't work and from my observations so far, the Connie and Starliner are in the same range of "very plausible" as is the B-377. Of course, the historical data is more available and honest for airliners than for the combat a/c as many of those were known for their propaganda numbers:kilroy:

Both the Evita and last year's Nobel events leaned toward 'realism' and I applaud the gang for their efforts and testing.
 
3/7charlie said:
Over Lean mixture will push the CHT up up up, and you will cook the engine. An accepted practice is to lean out the mixture untill you show EGT(if you have one) rise, then nudge it back towards rich. As altitude increases, air density drops, so the mixture needs to be leaned out.Over rich mixtures give lower temps but foul the sparking plugs. One can monkey with the mixture some from the book settings, but the mixture/MAP/RPM/Fuel flow graph has been arrived at by many,many years of trial and error and hard won experience. I have read several accounts of P-51 drivers getting home with cooling systems shot out by running full rich,and stroking the Kholer pump(manual primer) every 4-5 seconds to over rich the engine, keeping the temps just under the red line.It would run like crap, as the plugs fowled, so you quit pumping for a few moments to let the temps climb and burn the lead off the plugs. Don Gentle wrote that, after 2 hours or so of contiuous pumping nursing his Mustang back with a shot up rad, that he had worn the thumb out of his glove, and then wore the hide off his thumb down to the bone, the cockpit looking as if a hog was slaughtered in it, but that was preferable to being a POW.
Click to expand...

LOTS of info there, but generally your right- leaner mixtures run hotter ! An over-boosted under fuelled engine should've shown decreasing compression pressures until catastrophic failure (burnt rings, burnt valves, holes in cylinder, etc) no matter how cool you keep the cylinder jackets, but generally failure takes many hours of abuse.
 
Actually from more than that Dave.. my first NorthStar ride happened when I was 6 or 7. Dad worked for TCA and we lived 1/4 mile from Dorval so I was kind of immersed in it. Another member here at the Outhouse taught me to fly at 17 and I've pumped gas, groomed planes, towed them, washed them since I was 13 or 14.
One of these days when I find some time I'll go back and scan the slides I've collected of aircraft since 1960.

Yeah, I have one of those Dyson minds.. spins round and round and picks up a lot...

Rob
 
teson1 said:
Hey guys,
stop intimidating new people. :d
Click to expand...
LOL

We were all "new" once upon a time .. in a galaxy far, far away...

Just that some of us started before the dawn of time:rolleyes:

Besides, that's the fun of it - picking our brains for the bits that have been stored... if we can find them under all the other junk
 
I had a great time participating in the Evita Challenge. Initially I was a bit disappointed to have finished so far back in the pack but I have gotten over that.

What really gave me satisfaction was taking max loads and the right amount of fuel to avoid landing penalties. The Stratocruisers high fuel consumption outweighed the good speed and load carrying capability of the aircraft.

The B377 is very thirsty and particularly on climb to cruise where I needed to run auto rich to keep the engine temperatures down in the safe range. Once in cruise fuel consumption moderated significantly and as I was to run a much leaner mixture. The longer legs were better for me.

The legs in the tropics were tricky as I had to throttle back almost immediately after take off to avoid overheating. Lots of time spent opening cowl flaps and cooler flaps to keep the flight engineer happy. It took longer to get to cruise altitude too. Descents were less of a problem but required continuing attention to carb heat and flap settings. No combat descents in the 377. Too easy to overspeed and if you throw out flaps above 150knts they will jam. The Accusim add-on does promote “responsible” handling of your power plants. Push’m to hard and you will get a failure. It was very satisfying to complete the challenge on the set of engines I started with. Two were rated as in good condition and two were rated in fair condition at race end.

It was a lot of fun and I learned a lot.

Jeff W
 
I had a great time with the Evita and flying the JBK Stratoliner. I knew going into the event that I was behind the curve for speed and payload. I was just hoping that the 307's fuel economy would get me through. And I ended up finishing better than I thought I would.
 
We tried to write the rules in such a way that fire walling would be discouraged because it would lead to a “non-optimum profile”, in terms of fuel consumption, and this would cause people to fly by the numbers to save gas. This didn’t work out exactly like we had planned. We knew we couldn’t simply outlaw going fast, and it wasn’t explicitly stated in the rules that we wanted racers fly “by the numbers.” We wanted to make winning the race dependent on other factors that would naturally lead people to fly “correctly” to take advantage of those other factors, such as fuel efficiency and payload bonuses, as well as penalties for landing too heavy. We didn’t 100% succeed at this, but it did make for a fun and interesting event. Short of flying only planes equipped with A2A style “accu-sim” technology, the goal we set out to achieve with this race seems, at this point, almost out of reach. One simple way, I suppose, might be to provide each aircraft type with a “target” speed, and penalize the degree to which the target was missed, either under or over. The same way a handicap system works. I personally don’t like this approach because it’s too “artificial” and boring. We wanted flying by the numbers to be a logical consequence of the rules (if you wanted to win), and not simply the rule, if that makes any sense. Like I said, we didn’t quite succeed at that, but we’ll keep thinking about it!
 
You must log in or register to reply here.
Back
Top