After flying the RA Duke for about one month, I'm experiencing unexplained power loss. Firstly, FL240 MP 32", 2500 RPM, FF 114 PPH, IAS 150; everything normal. Thence, gradual power loss over the span of about 45 seconds to less than 14" ! Attempts to correct with mixture changes are futile. After about another 45 seconds, power returns on a gradual increase at about the same rate as the decrease. Assuming this is weather engine related, I'm using ASA with XG/FEX graphics. Now, following and emergency descent to 16 000, think once again normal. This is the second occurrence over two days. Les Parson

Keep an eye on the OAT gauge while this is happening.. report back

After flying the RA Duke for about one month, I'm experiencing unexplained power loss. Firstly, FL240 MP 32", 2500 RPM, FF 114 PPH, IAS 150; everything normal. Thence, gradual power loss over the span of about 45 seconds to less than 14" ! Attempts to correct with mixture changes are futile. After about another 45 seconds, power returns on a gradual increase at about the same rate as the decrease. Assuming this is weather engine related, I'm using ASA with XG/FEX graphics. Now, following and emergency descent to 16 000, think once again normal. This is the second occurrence over two days. Les Parson

Use your carb heat next time.

Wilco. It's gonna take me till about next weekend before I can do another test.

Wilco. It's gonna take me till about next weekend before I can do another test.

Even if an aircraft does not have carb heat, use the FS default key to turn it on. For whatever reason, this seems to be a FSX glitch that effects some of my FSX aircraft, even turbo/injection models.

Thanks for the advice; looks like "H" on the keyboard.

Thanks for the advice; looks like "H" on the keyboard.

I believe that is correct. I use voice commands, so when I do not have a carb heat knob, I simply say 'carb heat', and it switches on...or off. :(

I wasn't mentioning OAT for carb icing.. The Duke is fuel-injected, so carb-ice is not an issue (and why it shouldn't have carb heat).Some add-ons cause the weather engine to have ridiculously high temperatures at high altitudes.. which results in off-the-chart density altitude.. hence the power loss.

I wasn't mentioning OAT for carb icing.. The Duke is fuel-injected, so carb-ice is not an issue (and why it shouldn't have carb heat).Some add-ons cause the weather engine to have ridiculously high temperatures at high altitudes.. which results in off-the-chart density altitude.. hence the power loss.

As I said Brett, I encounter this with a few 3rd turbo/injection aircraft in FSX. FSX does not simulate actual turbo/injection equipped aircraft by it's design (only carbureted), thus you have to use it, even though you would not do so in real life. Myself and a few others had this discussion/issue in the ES forum a couple years back when we were encountering this loss of power issue in the SR22, an injection engine. Bill L, or Ron from Eaglesoft could explain the shortcomings of the FSX 'engine' better than I, as they have to design aircraft 'around' these inherent issues. The answer, finally, was to simply use carb heat, even though the aircraft isn't equipped with it. The same technique also works for other aircraft I have as well.Actually, I typically find this in lower (colder) temps at high altitudes, not high temps, or in combination with large fluctuations in air pressure per the 'weather engine', as you stated.

Interesting... In all my years of simming, and model design, I've never encountered carb ice at all. Plenty of frozen pitot tubes though.. LOLThanks for the explanation. From now on, all my fuel-injected aircraft will have an invisible XML gauge that makes carb-heat on at all times..As for my theory.. I've seen a few posts (maybe even one at this board), where the weather engine was giving an OAT of 45C.. that's nearly 200F.. and it was causing performance issues.Edit: That would be 200F at sea level, allowing for lapse rate (the 45C was at high altitude)

Interesting... In all my years of simming, and model design, I've never encountered carb ice at all. Plenty of frozen pitot tubes though.. LOLThanks for the explanation. From now on, all my fuel-injected aircraft will have an invisible XML gauge that makes carb-heat on at all times..As for my theory.. I've seen a few posts (maybe even one at this board), where the weather engine was giving an OAT of 45C.. that's nearly 200F.. and it was causing performance issues.

Actually, having it on all the time lowers performance to a small degree from what I've found. There are a couple aircraft I have that do not exhibit this issue, so some must have found the 'correct' tweak to eliminate the issue.Wow....45C degrees? That is indeed quite high if you are above 25,000. That said, IIRC, I use ASA (AS6 prior), and I do believe there was some issues with this, and I remember bringing it up with Jim of HiFi when 'we' were encountering the issue (there was a little 'finger pointing' going back and forth :( )....and then again after the initial release of ASA the air temps at 'level' altitude seemed too warm (noticed when I was flying the Aerosoft F-16 a bunch at 30,000+)....just not sure if this was resolved. I have not been flown at +20,000 for quite some time now. I have been flying the Duke below 18,000 most all the time.

Hi guys, really wierd that, I was just gonna post about this when i found this thread. I had nearly the same thing in a flight i just completed, only at low level, 8000 ft. Flying along, then the engine note decreases, I notiuce the manifold pressure going down to about 10 then it slowly picked up again. Happened 3 times on the flight. The second time, I switched on the fuel boost pumps and it came back up, but it happened again, with the pumps still on, about 20 minutes later. I could not see what was amiss, everything looked good in the pit. I thought it may be some kind of random failure, built in, but , i dont know.Be interested to see if any other duke pilots experience this. I had the new REX2 weather engine running at the time, weather good, light clouds and warm.cheers, Mark

This would actually be pretty cool if the power loss was programmed on purpose and the pilot had to troubleshoot the situation in the air. My instincts in the real world would be...- Carb heat and fuel pump on immediately. Since the Duke is fuel injected, this would not apply but sounds like FSX applies carb icing to all ACs- Check Mags. Do you notice a power difference on mag#1, mag#2, both?- Mixture. Increase mixture. Does that help? Decrease mixture. Any better?- Engine gauges - CHTs. Are all the CHTs about the same? Is any unusually high or low (I've not seen an FSX aircraft that emulates that well...)- Engine gauges - EGTs. Any unusually high or low?In my experience, one of the above 5 will point towards a cause of the problem and allow you to safely land under "normal" conditions. Now that you are thanking the good Lord that you made it back on the ground safely, its time to pray you find a good mechanic. This "temporary" problems are a bear to trouble shoot (and often expensive!). Oftentimes, an advanced engine monitor can help track down the cause of the problem. Talk about FSX being as real as it gets....! That would be fun.Anyways, its likely a programming bug but the discussion got me thinking how cool this would be if it were by design.

This would actually be pretty cool if the power loss was programmed on purpose and the pilot had to troubleshoot the situation in the air. My instincts in the real world would be...- Carb heat and fuel pump on immediately. Since the Duke is fuel injected, this would not apply but sounds like FSX applies carb icing to all ACs- Check Mags. Do you notice a power difference on mag#1, mag#2, both?- Mixture. Increase mixture. Does that help? Decrease mixture. Any better?- Engine gauges - CHTs. Are all the CHTs about the same? Is any unusually high or low (I've not seen an FSX aircraft that emulates that well...)- Engine gauges - EGTs. Any unusually high or low?In my experience, one of the above 5 will point towards a cause of the problem and allow you to safely land under "normal" conditions. Now that you are thanking the good Lord that you made it back on the ground safely, its time to pray you find a good mechanic. This "temporary" problems are a bear to trouble shoot (and often expensive!). Oftentimes, an advanced engine monitor can help track down the cause of the problem. Talk about FSX being as real as it gets....! That would be fun.Anyways, its likely a programming bug but the discussion got me thinking how cool this would be if it were by design.

Doug-I think it is probably a fs bug that applies carb icing to all aicraft-but your advice is correct.I think the fuel pump would be my first reaction.

Doug-I think it is probably a fs bug that applies carb icing to all aicraft-but your advice is correct.I think the fuel pump would be my first reaction.

Geof - I suspect you are right. BTW, I just missed you at Oshkosh. I stopped by the Flight1 booth and spoke with Jim Rhoades. I mentioned that I had followed his posts on several forums including Avsim. He chuckled and said he just finished chatting with another Avsim fan named Geof. I figured it had to be you and that we just missed each other by less than 10 minutes. I took a quick look around the hanger to see if I could find you but no luck. It would have fun to meet in person! Oh well, maybe next year....Oshkosh was a wonderful time. I took my 6 year old daughter and we camped there for 8 nights. There is so much to see and do there. my daughter has not yet caught the aviation bug but loved KidsVenture, the nightly movies (and the free popcorn!) and the Craft tent. So wonderful that they have such a large and enthusiastic group of volunteers to make it possible for people of different interests and ages to have fun. ....Come to think of it, I think it would be an ideal location for an Avsim gathering some year....