The A2A Simulations Community

"Come share your passion for flight"
It is currently Sat Oct 20, 2018 9:53 pm

All times are UTC - 5 hours




Post new topic Reply to topic  [ 48 posts ]  Go to page Previous  1, 2, 3, 4  Next
Author Message
PostPosted: Fri Oct 27, 2017 9:03 pm 
Offline
Technical Sergeant
User avatar

Joined: Sun Jun 10, 2012 6:23 pm
Posts: 576
Location: (S05) U.S.A.
Artur wrote:
So it looks like u are a good pilot and A2A did a proper research :-)

We all know that A2A has done their home work. Not sure just how good of a pilot I am but I do muddle through. The enjoyment of the Connie is amazing.

Roger

_________________
------ Fly Well, Be Nice, Have Fun ! ! !

Asus X99a | Core i7 5930K @ 4625MHz | G.Skill 16GB 3000 | EVGA 980 Ti SC | 950 Pro NVMe 256GB (OS) | 850 Evo 500GBx2 Raid0 | 3TB HDD | EKWB Custom Loop
P51civ - T6 - P40 - B17 - B377 - L049 - Comanche 250 - Spit


Top
 Profile  
 
PostPosted: Thu Nov 23, 2017 2:04 pm 
Offline
Technical Sergeant
User avatar

Joined: Sun Jun 10, 2012 6:23 pm
Posts: 576
Location: (S05) U.S.A.
Just an update on my engines. Today I hit 681 hours on my airframe. My freshest engine has 658 hours. This is over 100 hours on the engines sense they started showing "Poor" condition. I guess for Thanksgiving I can be thankful that they have not let me down yet. It will be fun to see just long I can make them last.

Cheers
Roger

Image

_________________
------ Fly Well, Be Nice, Have Fun ! ! !

Asus X99a | Core i7 5930K @ 4625MHz | G.Skill 16GB 3000 | EVGA 980 Ti SC | 950 Pro NVMe 256GB (OS) | 850 Evo 500GBx2 Raid0 | 3TB HDD | EKWB Custom Loop
P51civ - T6 - P40 - B17 - B377 - L049 - Comanche 250 - Spit


Last edited by WB_FlashOver on Sat Dec 23, 2017 3:18 pm, edited 1 time in total.

Top
 Profile  
 
PostPosted: Fri Nov 24, 2017 2:25 am 
Offline
Airman First Class

Joined: Wed Jul 01, 2015 9:43 am
Posts: 77
Location: Paris, France
WB_FlashOver wrote:
It will be fun to see just long I can make them last.


Very interesting :D

_________________
Image


Top
 Profile  
 
PostPosted: Sat Jan 06, 2018 12:41 am 
Offline
Technical Sergeant
User avatar

Joined: Sun Jun 10, 2012 6:23 pm
Posts: 576
Location: (S05) U.S.A.
So tonight I lost my first engine at 729 hours. Not quite sure what happened but on my way from Stockholm, Sweden to Berlin, Germany the engine failed. All gauges showed well within limits and the same as the other engines, i.e. torque pressure, oil pressure, fuel burn, RPM, temps etc, however the manifold pressure on engine 4 was an inch, maybe a hair more, under the others. I assumed I had lost a supercharger (nothing to critical, right?) so I did not shut it down as I divert to Neubrandenburg AB, Germany.

Should I have shut engine 4 down? Would the Maintenance Costs have been lower if I had? Was the engine completely dead and windmilling and if so why would the manifold pressure so closely follow the other engines as throttles changed and why would RPM's mimic the exact same as the other engines?

Looking for suggestions, ideas, input.

Also, if I was not considered to be responsible for the "RARE AND SUDDEN FAILURE" then why would they dock my salary $2,507.00? This is a real conundrum! This makes me want to return to my last saved data file and rebuild all engines before flying again. I might just do this, not sure yet.

Thanks much
Roger

Image

_________________
------ Fly Well, Be Nice, Have Fun ! ! !

Asus X99a | Core i7 5930K @ 4625MHz | G.Skill 16GB 3000 | EVGA 980 Ti SC | 950 Pro NVMe 256GB (OS) | 850 Evo 500GBx2 Raid0 | 3TB HDD | EKWB Custom Loop
P51civ - T6 - P40 - B17 - B377 - L049 - Comanche 250 - Spit


Top
 Profile  
 
PostPosted: Sun Feb 04, 2018 5:38 pm 
Offline
Staff Sergeant

Joined: Sun May 27, 2012 7:32 pm
Posts: 390
Quote:
So tonight I lost my first engine at 729 hours. Not quite sure what happened but on my way from Stockholm, Sweden to Berlin, Germany the engine failed. All gauges showed well within limits and the same as the other engines, i.e. torque pressure, oil pressure, fuel burn, RPM, temps etc, however the manifold pressure on engine 4 was an inch, maybe a hair more, under the others. I assumed I had lost a supercharger (nothing to critical, right?) so I did not shut it down as I divert to Neubrandenburg AB, Germany.

Should I have shut engine 4 down? Would the Maintenance Costs have been lower if I had? Was the engine completely dead and windmilling and if so why would the manifold pressure so closely follow the other engines as throttles changed and why would RPM's mimic the exact same as the other engines?

Looking for suggestions, ideas, input.

Also, if I was not considered to be responsible for the "RARE AND SUDDEN FAILURE" then why would they dock my salary $2,507.00? This is a real conundrum! This makes me want to return to my last saved data file and rebuild all engines before flying again. I might just do this, not sure yet.

Thanks much
Roger


Ah heck, in today's dollars it only cost about a million dollars or so to overhaul a big Wright. With the recent tax breaks afforded us by Congress, this should be easily doable now. :wink:

Okay, before starting a politically laced thread tirade, I'm wondering if you guys are flying the published BMEP setting for climb and cruise, as well as keeping BMEP out of the negative torque regime on descent and approach. On the real aircraft, I'm assuming the quoted BMEP figures were as much to reduce engine wear as they were for fuel economy, and these torque values were always used instead of manifold pressure to set climb and cruise power. I'm not sure how much Accusim would actually take into account though when it computes wear on the engine. I think Scott Gentile mentioned that Accusim accelerates normal engine wear too to provide a richer simulation experience.


Top
 Profile  
 
PostPosted: Mon Feb 05, 2018 12:12 am 
Offline
Technical Sergeant
User avatar

Joined: Sun Jun 10, 2012 6:23 pm
Posts: 576
Location: (S05) U.S.A.
Hobart Escin wrote:

Okay, before starting a politically laced thread tirade, I'm wondering if you guys are flying the published BMEP setting for climb and cruise, as well as keeping BMEP out of the negative torque regime on descent and approach. On the real aircraft, I'm assuming the quoted BMEP figures were as much to reduce engine wear as they were for fuel economy, and these torque values were always used instead of manifold pressure to set climb and cruise power. I'm not sure how much Accusim would actually take into account though when it computes wear on the engine. I think Scott Gentile mentioned that Accusim accelerates normal engine wear too to provide a richer simulation experience.

Hello Hobart,
I am starting to have questions about this very subject. My normal settings are:
Takeoff- 140-145 BMEP @ 2600 RPM (runway length and density altitude allowing)
Cruise- 130+/- BMEP @ 1700+/- RPM (this is variable but always in this ballpark) (FL200-FL240)
Descent- 100 BMEP @ 1550-1600 RPM (depending on my rate of descent but usually around 18-20" MP @ said RPM)

My issue is that I always treat my engines very nicely but my maintenance costs average just under $40.00 per hour. I have flown with friends that departed 30 minutes after me and they ran hard, 32" over 2300 RPM, to catch up and they end the flight with $0.00 maintenance costs while I still have my $40 per hour costs. I, personally, have never seen $0.00 maintenance costs. It doesn't make sense. I am not a pilot nor an airplane engine mechanic but I do know engines to some point and I know that the kinder you are to them to longer they last. I do see others posting their flight logs with some very high maintenance costs but I don't know their engine settings during the flight to compare.

Lately I have been trying higher settings but have not noticed any noticeable change in costs, accept for fuel costs.

Cheers
Roger

_________________
------ Fly Well, Be Nice, Have Fun ! ! !

Asus X99a | Core i7 5930K @ 4625MHz | G.Skill 16GB 3000 | EVGA 980 Ti SC | 950 Pro NVMe 256GB (OS) | 850 Evo 500GBx2 Raid0 | 3TB HDD | EKWB Custom Loop
P51civ - T6 - P40 - B17 - B377 - L049 - Comanche 250 - Spit


Top
 Profile  
 
PostPosted: Mon Feb 05, 2018 6:34 am 
Offline
A2A Aviation Consultant
User avatar

Joined: Mon Mar 03, 2008 12:06 pm
Posts: 2099
Location: Wichita Falls, Texas, USA
Run the engines at their charted settings. DO NOT use reduced takeoff power or climb. Only use the charted and recommended settings in cruise.

This is a misnomer with piston engines - they LIKE to be run hard. When you try to "go easy" on them, you do things like foul plugs, allow lead buildup on the rings, and worse. You need to keep the engines warm so that the rings stay properly seated too.

I've seen how "reduced power" takeoffs and odd power schedules kill R2800s. Even on 100LL, as long as you run the max dry power (50") on takeoff (even with water injection on) and then 1100HP cruise (ECON Cruise) and follow your proper climb stage power, the engines last 1500+ hours. It's when you start mucking with the power settings (like holding METO until top of climb, running 1000HP cruise, or worse- uncharted cruise settings) that the engines start eating themselves and lasting only 100 hours. Not running them regularly when not flying also will kill engines. We ran them for an hour once a week when they weren't flying, to include several full-power runs (with cool downs between). These keep the piston rings properly seated and make sure the oil is out of all the "low spots".

With Accusim, while it's not specifically modeled, what is modeled is the engine knowing when it's in the "sweet spot" or not and the maintenance and wear works off of that.

_________________
Image


Top
 Profile  
 
PostPosted: Mon Feb 05, 2018 8:01 am 
Offline
Staff Sergeant

Joined: Sun May 27, 2012 7:32 pm
Posts: 390
WB_FlashOver wrote:
Hobart Escin wrote:

I am starting to have questions about this very subject. My normal settings are:
Takeoff- 140-145 BMEP @ 2600 RPM (runway length and density altitude allowing)
Cruise- 130+/- BMEP @ 1700+/- RPM (this is variable but always in this ballpark) (FL200-FL240)
Descent- 100 BMEP @ 1550-1600 RPM (depending on my rate of descent but usually around 18-20" MP @ said RPM)

Roger


As CAPFlyer mentioned, your takeoff power setting is pretty low. I don't even reference BMEP settings until reducing from METO to normal climb power. I use 46" @2600rpm for takeoff and hold that power setting until completion of gear retraction, then reduce power to METO (40" @2400 rpm), and hold METO until about 1500' AGL. Finally, I reduce to published climb power setting of 145 BMEP @ 2300 rpm. I use whatever manifold pressure setting will yield 145 BMEP until reducing power at cruise, then fly published cruise power setting. On descent, I reduce to 20", keeping the props at their 2000 rpm cruise setting and holding this until in the terminal area.

Before pattern entry, I come back to 1800 rpm on the props and 15-16" MP. This seems to keep the BMEP safely out of negative torque as well as maintaining hydraulic pressure.


Top
 Profile  
 
PostPosted: Tue Feb 06, 2018 1:03 am 
Offline
Technical Sergeant
User avatar

Joined: Sun Jun 10, 2012 6:23 pm
Posts: 576
Location: (S05) U.S.A.
Hmmm, Ok this is a hard concept to wrap my head around. I don't want to sound argumentative so let me say that this is not the purpose for this post. I just need to understand.

Since age 10 I have been on equipment. Tractors, dozers, loaders, excavators, 4x4 Jeeps & pickups, etc. I have rebuilt several engines, diesels and gas. I have been told several things over this time. One of the things that I have been taught is that revolutions produce wear on internal parts. Wear on main bearings, rod bearings, wrist pins, cam bearing, lifters, followers, rocker arms, push rods, etc. With each revolution cycle increase, the wear increases. Wear does not just increase in accordance with the amount of revolutions, it increases exponentially. An engine running at 2000 RPM does not produce double the amount of wear as an engine running at 1000 RPM's, it is much more. If the RPM is allowed to continue to increase there will eventually be catastrophic failure. The stress on parts such as rods, crank, cam, pistons and valve train within a reciprocating engine increase exponentially as well with RPM increase.

This all makes a lot of sense to me. A racing engine with high dollar lite-weight parts will last much longer at 8000 RPM than a stock engine but it will still need to be rebuilt much more often than if it were run at 3000 RPM. So, now I am told that running an airplane engine hard will make it last longer, well, it's just hard to wrap my head around it. I fully agree that lugging an engine will kill it too but backing off a couple of hundred RPM and pulling the throttles back a few inches of MP to create less power does not seem to warrant lugging or abuse.

I have found that running near the 43" 2500 RPM in the P-51 requires new cylinders, bearings, etc much more often than running 30" 1800 RPM or even less. When driving truck I use only the power needed at the time it is needed. I don't run the engine at it's governed RPM while tootling down the street empty. However, while pulling 76,000 lbs of concrete up a 7% incline I will run it as hard as needed.

This is just hard for me to grasp. I do plan on increasing power settings to see if the maintenance costs will decrease. It could be that the costs that Accu-Sim is giving me has nothing to do with the way I am running the engines.I top the fluids off on every flight and maybe the maintenance cost has to do with they fluid cost. I know that somewhere I heard or read Scott say that one might just end up reducing power settings in the Connie to see how long they can make the engines last. I looked for it tonight but could not find that statement. It was around the time that the Connie was released. Maybe someone else knows of this.

Cheers and thanks for the replies Sirs.
Roger

_________________
------ Fly Well, Be Nice, Have Fun ! ! !

Asus X99a | Core i7 5930K @ 4625MHz | G.Skill 16GB 3000 | EVGA 980 Ti SC | 950 Pro NVMe 256GB (OS) | 850 Evo 500GBx2 Raid0 | 3TB HDD | EKWB Custom Loop
P51civ - T6 - P40 - B17 - B377 - L049 - Comanche 250 - Spit


Top
 Profile  
 
PostPosted: Tue Feb 06, 2018 4:42 am 
Offline
Senior Airman

Joined: Thu Oct 10, 2013 9:35 pm
Posts: 161
Hi Roger,

Because I have an idea of what I'm looking for, and where to find it, I have this link related to the question of "going easy" on high performance aero engines. I hope you enjoy it. I learn something new every day with these curious flying machines, and I know we will all keep doing so in this great hobby. Enjoy.
http://www.enginehistory.org/Operations/wbn/WBN11.pdf


Top
 Profile  
 
PostPosted: Tue Feb 06, 2018 7:01 am 
Offline
A2A Mechanic
User avatar

Joined: Sun May 26, 2013 5:03 am
Posts: 3878
Also, recall that running an airplane engine at high power does not usually mean that high RPM. Airplane engines are generally operated at very narrow RPM range (narrow enough to allow for their fixed ignition timing).

Running them at or near absolute maximum rated power or redline RPM is harder on them than running at nice modest cruise setting, but is needed for much less time. Also, they are designed to handle that, though not necessarily for very long periods due to potential overheating.

-Esa


Top
 Profile  
 
PostPosted: Tue Feb 06, 2018 7:19 am 
Offline
A2A Aviation Consultant
User avatar

Joined: Mon Mar 03, 2008 12:06 pm
Posts: 2099
Location: Wichita Falls, Texas, USA
Roger, your problem is your experience. ;)

I'm being tongue-in-cheek about this, but it's true to a certain extent. Aero engines (not just high performance ones, any piston or turbine engine designed for aeronautical use) are not the same as whats in your car, your truck, or your tractor.

The common point is this - Aero engines are designed to run at high power for long periods of time. Turbines more especially than pistons, but the principle is still the same. Aero engines spend most of their lives at or near their "rated power". On a jet, this is whatever they determine to be 100% rotation speed for the compressor, and on a piston, this is whatever they determine to be the cruise power band (typically between 65% and 75% rated power). The engines in your land vehicles spend most of their lives changing power. As such, they are designed to deal with that. As such, most land engines take the least wear at low RPMs. However, because an Aero engine is designed differently, when the engine is working hard, it's doing so in a balanced way. The long-stroke, low compression cylinder design of the Aero Engine makes it so that you're producing a TON of torque (work) for not much energy, and that greatly reduces wear. Most of your aero engines run at less than 1/2 the compression ratio of a diesel, and about 1/3 less than a gasoline engine.

Here's some examples -

Radials (Wright, Pratt & Whitney)
R975 - 6.3:1 (420 hp)
R985 - 6.0:1 (400 hp)
R1820 - 6.45:1 (1000 hp)
R1830 - 6.7:1 (1200 hp)
R2800 - 6.75:1 (2400 hp)
R3350 - 6.85:1 (3000 hp)
R4360 - 6.7:1 (3000 hp)

Water-Cooled (Allison, Rolls Royce)
V1710 - 6.65:1 (1500 hp)
Merlin 61 - 6.0:1 (1200-1500 hp)
Griffon 65 - 6.0:1 (2500 hp)

Horizontally Opposed
O-360 (C-182) - 8.5:1 (235 hp)

Gasoline Engines
Chevy LS6 - 10.5:1 (350 hp)
Ford 5L V8 (2018) - 12.0:1 (300 hp)

Diesel Engines
Navistar T444E (7L V8 diesel built pre-Tier3) - 17.5:1 (210 - 275 hp)
PowerTech series (John Deere Tractors, modern Tier4) - 16.0:1 - 17.0:1 (50 - 600 hp)

Marine Diesel Engine
Wartsila 20 (modern ship engine) - 15:1

So, as you can see, even at high power settings, you're not putting nearly as much stress on the engine as you would at high power on the engine in your car or truck (or even ship). This is the secret.

_________________
Image


Top
 Profile  
 
PostPosted: Tue Feb 06, 2018 7:21 am 
Offline
A2A Aviation Consultant
User avatar

Joined: Mon Mar 03, 2008 12:06 pm
Posts: 2099
Location: Wichita Falls, Texas, USA
AKar wrote:
Also, recall that running an airplane engine at high power...


This is what I get for taking an hour plus to write and make sure I've got good numbers in my post. :lol:

_________________
Image


Top
 Profile  
 
PostPosted: Tue Feb 06, 2018 9:54 am 
Offline
A2A Mechanic
User avatar

Joined: Sun May 26, 2013 5:03 am
Posts: 3878
CAPFlyer wrote:
This is what I get for taking an hour plus to write and make sure I've got good numbers in my post. :lol:
Don't worry...I've had my hour of labor in collecting some stuff in a table for some statistical comparison... :mrgreen:

Image

So far I've got the specs of about two hundred Lycomings for stats, when I find some time I add the Continentals as well.

-Esa


Top
 Profile  
 
PostPosted: Tue Feb 06, 2018 10:47 pm 
Offline
Technical Sergeant
User avatar

Joined: Sun Jun 10, 2012 6:23 pm
Posts: 576
Location: (S05) U.S.A.
Salute Sirs,
This is all fascinating information. Very informative indeed. I know you all have put some time into bringing me up to speed.

I was under two assumptions.

1) A reciprocating piston engine, is a reciprocating piston engine, is a reciprocating piston engine. Sure there are many differences with stroke, bore, valve train layout, etc, etc. I understand now that airplane engines are created differently.

2) I was always under the assumption that using full takeoff power is for safety sake, "Don't dilly dally, get her airborne". I also thought that the listed climb and cruise settings were considered to be the max, or do not exceed, settings. Not "use these or expect failure" settings. I figured this in part to the fact that airplane engines get regular inspection and maintenance where car and truck engines get attention when they start to make funny noises or stop running. The mixer truck I drove prior to the one now had 2200 miles on it when it arrived at the plant. When it went to a different location I had put over 150K miles and over 14K hours on it and it was still going strong. That would translate to a lot of inspections and several overhauls on an airplane engine.

You have me curious enough now to do more research. I may have to take some time at my local State airport and talk with the mechanics at Frank's Flight Service.

Thanks again for your time.
Roger

_________________
------ Fly Well, Be Nice, Have Fun ! ! !

Asus X99a | Core i7 5930K @ 4625MHz | G.Skill 16GB 3000 | EVGA 980 Ti SC | 950 Pro NVMe 256GB (OS) | 850 Evo 500GBx2 Raid0 | 3TB HDD | EKWB Custom Loop
P51civ - T6 - P40 - B17 - B377 - L049 - Comanche 250 - Spit


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 48 posts ]  Go to page Previous  1, 2, 3, 4  Next

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 3 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group