I just took it up for a first flight. My first impressions were good, and I think this is my new favourite aircraft (sorry, Cessna 421C). As I climbed to 8000 ft, my engines suddenly shut off. I was unable to get them started so I had to land in a nearby field. I couldn't get the engines started again, so I exited FS, and went to the load utility to see if it actually logged my engine hours. Sure enough, it did, and it also told me that my engines were now "damaged".I guess the moral of the story is "don't fly around at full throttle", or "check an engine gauge once in a while". 10 minutes of flight cost me $67,200 "virtual" dollars, but it's nice to see an aircraft that has this sort of feature. It sort of reminds me of Lagos FSMaintenance, but this is a little nicer since it is aircraft-specific.Anyway, I'm pretty happy with it.- Martin

There are basically two ways to damage a piston engine:- Overstressing it: Note that an engine overstresses when it's flown at high manifold pressures or incorrect Manifold Pressure/RPM settings (oversquaring). The throttle setting is not really relevant here, you can fly full throttle at 10.000 feet without overstressing the engine, since the manifold pressure is not very high at high altudes. FSMaintenance didn't get this right and penalized every throttle setting about 95%, if I remember correctly. Too bad, it wasn't very usefull for GA flights.- Rapid temperature changes: Shock heating and cooling should be prevented by using leaning and cowl flaps correctly.Of course there are plenty more ways to kill an engine, but I think these are the most important ones. Can anyone shed a light on FSD's implementation of damage modeling? I've been looking for correct engine damage modeling and the FSD Navajo looks promising.

Well don't know if this applies to your overstressing but I was crusing to KOSH at over 200 MPH and decided to throw in some real world weather. Soon after restarting, the aircraft started to buck and shake all over the place until I brought the speed down to about 180. Thereafter if was pretty smooth. I was impressed! I really like this aircraft. Great job FSD!Jim

We've refined the damage profile for the Navajo.This is a TC engine so the comments about firewalling it and power progressively falling away as altitude increases (true of a nomally aspirated engine) don't apply here. Managing a TC engine is actually a lot easier than a recip, as long as you pay attention and understand the factors involved which are basically heat, time, airspeed and procedures.As IRL, a relatively high output recip engine like this has a limit on how long you can pull maximum power from it without consequences. Mostly the engine limit is due the cooling system for oil and CHT. A limit of 3-5 minutes at full power is the general rule for a similar engine following take-off above which temps and pressures trend unfavourably. That interval is what you get in the Navajo 'free of consequence' : beyond that there are random states and temporal factors that accumulate if you ignore limits. A count-down if you will. As for cruise (the prepared high-mid-low power altitude tables which escaped the POH, an omission to soon be corrected), provided you don't exceed the max continuous power limit of 85% 'indefinitely' (conditional on not operating below the recommended climb speed) - you will not see problems. This info is in the kneeboard files by the way and you need to either (1) read these files, or (2) turn off the damage profile in the Load Manager. There are *also* other params. For example, the cool-down interval after landing is another (see the ref files) : you have to observe the two minute cool-down before shut-down. Why ? Because it's normal for a TC engine to be allowed to cool so the turbocharger temps fall below that at which oil will coke the turbocharger oil galleries leading to a premature failure. FS models thermal events miserably so we have stuck you with a hard time limit much as the extended idle 'turbo timers' you note in some high performance turbocharged automobiles.We have made it more complex, but ultimately you can turn it all off if you like. The only thing I am not sure of is why we are seeing a few reports of both engines simultaneously failing as we programmed this as a random L-R event so you would have to fly using asymmetric procedures. If it is not duplicating just that, we will ascertain the reason why and fix it so it will reliably fail one engine randomly, consistently (an oxymoron, yeah I know ...).Hope this helps.Best,http://www.fsd-international.com/team/Steve_signature.gif

No offense Barry, but I have two other FSD add-ons, therefore I'm familiar with how they model damage by not allowing one to overstress the engines and so on. Also, if you have flown a good number of add-ons, or even a real plane, you become acquainted with system operation, thus reducing the need to read the entire manual just for a test spin.Chris

Steve,Thanks for this information. I took off from Princess Juliana into a tropical storm when both engines failed about 3 minutes after departure (OK I know it was stupid - but this is a sim so we can try out this sort of stuff!!) Strange thing is that, now, whenever I select the Navajo it won't start! How long do I have to sit in the sin bin for? Joking apart - a great aircraft and virtual cockpit - I'd just like to be cut some slack and get the engines started again!!Kev:-)

>Steve,>>Thanks for this information. I took off from Princess Juliana>into a tropical storm when both engines failed about 3 minutes>after departure (OK I know it was stupid - but this is a sim>so we can try out this sort of stuff!!) Strange thing is that,>now, whenever I select the Navajo it won't start! How long do>I have to sit in the sin bin for? Joking apart - a great>aircraft and virtual cockpit - I'd just like to be cut some>slack and get the engines started again!!>>Kev:-) You have to go back into the Load Manager program and "fix" the engines.- Martin

Great plane and lots of features.Love clicking on the circuit breakers-tried pulling the gear breaker and sure enough-it worked.Fantastic job-thanks!http://mywebpages.comcast.net/geofa/pages/Geofdog2.jpg

I am HUMBLED .. very much so.1. Read all the instructions, follow the checklists .. t/o PHNL 22 on my way 73 miles to Lanai City ... PHNY. I was at 2500 feet, engines died, could not be started. Madre de la luz, tenga piedad en los ciegos!!!!! I was able to bring the Navajo around and land .. not sure how but it surely glided nicely.2. I spend the next hour trying to start the GD engines ... I tried every thing written .. no joy. Then I tried the FSD forum ... registered some time ago (have all their planes) .. could not log on ... some GD message about fixing my browser or security software for referral logging ... GOOD GRIEF .. WHAT IS WITH THAT??? I looked all over IE, and my firewall ... Zone Alarm ... SO YOU PAY YOUR MONEY AND YOU CAN'T USE TECH SUPPORT .. GRRRRRRRRRRRRRRRR3. Finally came here to AVSIM .. and found the usual friendly INFORMATIVE posts and didn;t feel so bad. Looked at the load manager and engines ere damaged. Fixed4. Ok again .. RW 8 this time the winds were calm ... off I go ... at 750 feet throttle back and adjusted prop not to TAX the baby. OK so far so good .. turned on to my path .. at 3000 set AP on and slaved to the 530 and relaxed ... throttled back and adjusted prop for 5000 ft .. 33mag/2500rpm .. adjusted mixture to 1325 deg .. humming along nicely ... to MKK VOR ...(molokai) .. 4 miles off coast .. both engines died ... could not restart ... tried to glide to an little airport near the coast, but could not fly and try the engines over and over (thus the need for a co-pilot or to be an octopus or perhaps a squid) .. and of course, I put the gear down and landed on a little road ... MORE DAMAGE ENGINES ...What did I do wrong now? C421 never treats me like this. Looked at loader .. set to easy ... I suppose I should set to OFF ..Not having fun.I am getting OLD and very tired, it's been a long terrible week, bought a new toy .. more complex than a 747-200 to fly.I feel ignorant, stupid and very humble .. Any thoughts??

The FSD planes are very sensitive when it comes to RPMs and MP. I think the Navajo may have a few minor bugs in this respect, but the Cheyenne is sensitive as well, so what do I know.Before even taking off I set the prop levers to 80% and the mixture to whatever depending on altitude. When taking off, try and keep the manifold pressure in the green at least after initial climb out. Also, watch your airspeed, my was really high with the throttle and MP in green. I flew a hundred mile trip to KACK last night without a problem. Just keep the RPMs well below the end of the green strip, and everything else in green, and you should be fine. Also, keep the airspeed down below 160 or so. Hope this helps,Chris

Look like if you look in the FSD Navajo folder-there is a folder called "manual" with much of the info you need.http://mywebpages.comcast.net/geofa/pages/Geofdog2.jpg

I am enjoying this bird. Oh those engines what beautiful sound they make. I can almost smell the fuel.As for the damage modeling, I really enjoy the realsim it adds. Gives you a sense of accomplishment when you get the bird up to cruise altitude, pull back to cruise, and she humms along. It really is something to enjoy.As I said on the FSD forums, you guys have done it again. I am really digging my GA fleet now, so many really good planes. Thank you guys.I hope everyone else is enjoying these aircraft like I am.

http://www.forefrontgrp.com/jayssigsmall.jpg"There is an art . . . to flying. The knack lies in learning how to throw yourself at the ground and miss!"

Ahhh touche ;),but if you read the manual and checklists they state, climb MAP should be lower than 38, and Climb RPM should be 2500rpm.Now if you are to use these settings with "real-world" damage modelling your oil temperature will go through the roof and your engines will die.Now if you reduce the RPM to 2100rpm everything seems fine, so I deduce from this that either the checklists are wrong, or the damage modelling is damaging the engines when it should'nt.I hope FSD can look into this.Also another thing I noticed was if you try to uninstall the Navajo and you have the seneca installed it will try to uninstall the Seneca instead, wierd.CheersDan.

Thanks Steve, this looks promising. Downloading now!:-)

Paul,After retracting the gear and establishing a positive rate of climb, try retarding the RPM to 2250-2300 for your climb/cruise. You only have about three mins at 2500 by my calcs before you start to do some damage.Cheers,Chris Porter:-outtaPerthWestern AustraliaMy "Around the World 4" flight pagehttp://members.iinet.net.au/~portercbp/fly...e%20World_4.htm