10 knots/second deceleration at idle fix

[pilotjohn 19]

Has anyone found a solution to the 10 knots/second deceleration at idle (F1)? That is, there is a small throttle "boundary" at which point the plane either decelerates normally, or switches to a ridiculously fast rate of deceleration on the order of 10 knots/second. While it's been discussed that then putting the plane into reverse range (yes, I'm aware of the general problem with this) reduces the magnitude of deceleration (which is counter-intuitive to how real planes would behave), I'm really just looking for a fix so you can fly steep stabilized approaches without having to jockey the throttle around this boundary. I've compared the AIR files between the Carenado 208 and the stock 208 with AAM, but I didn't see anything obvious.

[Buzz313th 0]

I am in the same boat as you. The throttle triggered gauge file that increases drag is a complete showstopper for me as it makes fine throttle modulation on approach completely impossible. I guarantee that the 208 does not behave this way and that if reducing the throttle to idle and prop to high rpm causes a large amount of decel then in the real plane the pilot would be able to feather it's effect. With the current ver of the carenado 208, the drag effect is either on or off with no way of transitioning smoothly. I believe the reason that they did this is because fsx does not model the correct amount of drag on a closed throttle in turboprops, so carenado programmed a gauge file that at closed throttle either opens invisible spoilers or just increases drag. By the way, you can disable the drag gauge file and get rid of the drag effect, but then it makes the 208 impossible to slow down on a steeper than 3 degree descent path. I have emailed carenado and asked them if they could address the issue, but I have yet to hear back from them. I wish I had bought the addon from flight one so I could get a refund, but I bought it straight from Carenado.I am curious what they are gonna do for their upcoming kingair. I they use the gauge file approach to add drag then it's gonna behave almost the same.Hopefully Carenado will re address this issue.JB

[Avi8tor1 1]

I honestly think its beta. Though it doesn't make sense to have it there - as it should actually be flight idle. Thus, the prop become a massive speed brake and the plane nose dives. You are to never put a PT6 in beta because you'll snap the prop, snap something within the engine or in the case of a wing mount rip off the nacelle or worse - the entire wing. So I don't see the point of this being simulated in the alpha position (forward thirst). Just my 2 cents and turbo info ;)

[Guest bstolle]

Just for clarification, 'beta' is not necessarily related to forward or reverse thrust. Beta just defines the area at which the prop angle is being controlled by the throttle and not the prop lever.E.g. on the Dash 7 flight idle is well within beta range. Although not recommended or certified, some PC-6 pilots use ground idle and even lower prop pitch in flight without ripping the engine or the prop off etc... According to a few 208 pilots, the flight idle stop on the 208 has a very low pitch setting and this does create a lot of drag.

[Guest BeaverDriver]

Some Twin Otter pilots doing sky dive flights at high altitude (i.e. 10,000 roughly) get up there over the airport or dropzone (often the same), drop their load, then go to reverse and virtually come straight down so as not to take all day to get up and down again for each drop. At one time (and might still be possible). Twin Otter drivers would get the machine into reverse as they were starting to flare if coming in on a very tight "runway" (i.e. a gravel beach, piece of flat tundra, etc.). The actual machines have a "gate" on the thrust lever that prevents you from inadvertently pulling the thrust lever too far back, but if you want to pull it back deliberately, you can. It's not possible to model that in FSX so you simply have to note where the "cutoff" point is and not go below that. Yes, you aren't able to achieve a steep descent without getting into the beta or reverse position, but the real thing can't either. The Caravan is not a STOL aircraft, but it can be made to do some pretty short landings if you want to get into that region. Like with the real thing though, it really helps to know what you are doing. Insofar as the prop acting as a brake when you push the prop pitch full forward - that too is very realistic. Going to full fine pitch with low rpm's is like gearing down severely in a standard transmissioned car. It does help you slow down, here and IRL.

[Buzz313th 0]

My issue is not with the amount of drag at low prop pitch and flight idle, but with the transition delta from the point at which we go from partial throttle to flight idle and the carenado 208 suddenly decelerates at a fixed rate with no linear transition. During throttle movement towards flight idle, the drag intensity created by prop pitch change should be gradual, not sudden.JB

[pilotjohn 19]

A fix for the Carenado 208 idle deceleration flight dynamics is to edit aircraft.cfg and change...the spoiler_limit from 90 to 75 (optionally 60)the spoiler_extension_time from 1.0 to 5.0 (optionally 3.0).They're using a spoiler trick to allow the plane to decelerate by creating a 90 degree deflection of the "phantom" spoiler.The stock FSX 208 is 20. The Carenado will have a harder time stalling with anything less than 60 because of their engine/power tweaks.So, using 75/5.0 will give about 97% of the original deceleration - sin(75) - but it will "kick-on" in 5 seconds, not 1. This time extension will make it easier to joggle the throttle back and forth between the deployment boundary, and using 75 instead of 90 won't require 17% of the total time to be spent getting rid of only 3% of the drag.Using 60/3.0 may be more comfortable to some, and it will still provide 87% of the original deceleration drag, and won't require 33% of the time to eliminate only 13% of the drag. The plane will have a slightly harder time stalling with flaps up and idle power at this setting, but then again it was pretty reluctant to stall as-is.

[Buzz313th 0]

Funny how you started this thread looking for a fix and yesterday posted a viable bandaid fix for it yourself. Thanks.I was hoping for a more elegant fix from Carenado. With the one you have posted, we are still dealing with the inability to modulate the throttle for a steady state approach. JB

[Guest BeaverDriver]

My issue is not with the amount of drag at low prop pitch and flight idle, but with the transition delta from the point at which we go from partial throttle to flight idle and the carenado 208 suddenly decelerates at a fixed rate with no linear transition. During throttle movement towards flight idle, the drag intensity created by prop pitch change should be gradual, not sudden.JB

Oh, ok I see what you are saying now. Yeah, it's pretty abrupt alright (found that out the hard way once on short final - recovered in time but it did get "interesting" for a minute ). I think it does happen IRL fairly abruptly, but not like what is modelled here, so I have to agree with you on this one. I'll give the fix above a try (thanks for that) and see how that goes.

[pilotjohn 19]

Funny how you started this thread looking for a fix and yesterday posted a viable bandaid fix for it yourself. Thanks.I was hoping for a more elegant fix from Carenado. With the one you have posted, we are still dealing with the inability to modulate the throttle for a steady state approach.JB

Well, I went hunting on FSDeveloper about dynamics to find a cause; I found it. For Carenado to fix this right, they would have to scrap and start from scratch. From cursory reading, I think they were trying too hard to match exact cruise speeds and that resulted in some duct tape elsewhere (seemingly where it really matters). I also think the plane has too much power and climbs too fast even at MTOW (1000 FPM+ way above Vy above ISA), when the book says 975, and that's optimistic (I have 2 flights and about 1 hour in a C208), and at lighter loads (6000 lbs) it's like a rocket. I haven't measured ground-roll, but I would venture to guess that's also too short. Too bad, because it would be in my top 3, but because of the patch-work dynamics, it's not even close. I hope they do a better job with the C90.

[Buzz313th 0]

I'm right there with you. I think Carenado does an amazing job with the 3d modeling and textures, but some of the flight characteristics of some of the planes are haphazardly put together like the 208. I really hope they take another look at the 208 and find solution to make flying the 208 on approach anything but completely uncomfortable like it is now. This plane would be my favorite aircraft up in the orbx pnw, but the throttle control during approach is absolutely hideous. If I kept flyin it I would end up getting into a bad habit of over controlling throttle on final. Until a proper fix comes along, I hate to say that I won't be flying it at all. It just feels too uncomfortable.Like I said in an earlier post, I wish I had bought it from flight one and then I could of returned it after finding this out.JB

[Avi8tor1 1]

Sorry guys, time to throw my complete understanding of beta out the window : I just can't seem to wrap my head around the operated of free turboprops. I have a solid understanding of geard turbos, pistons and jets. I was recently on a Q400 and the FO told me that Beta was anywhere from flight idle and back (reverse) and alpha is anything from flight idle and forward...hmmm :PThe reason I say never to put the 208 in beta is "a" because I had a completely different understanding of what beta wasy and "b" my friend flies a 208 for Fedex and he said that he would NEVER put it into beta during any stage of flight. But that could just be his SOP's.Could anyone fill me in on what beta is? :) Thanks!Regards,Cameron Caldwell.P.s. Sorry for stealing your thread pilotjohn

[taguilo 33]

I've made some changes in the gauge that controls drag on the Caravan. The trick to use invisible spoilers is a good one indeed, mostly because one can play with different flight and ground conditions.In this case, I added a polinomial that controls the increase of drag in a smooth way, taking into account the propeller status -if it's feathered, no drag at all-Also, as soon as the aicraft is landed, spoilers are removed as to extend the landing roll and improve the reverse throttle. On the other hand, a bit of spoilers are added in the take off roll, -up to 60 kias- as to extend the take off as well.All the variable values and triggers were estimated by me, who has no real Caravan flight experience so I'd be glad to send this gauge to anyone that would like to test it and help me find the most accurate behavior.Regards,Tom

[Buzz313th 0]

I've made some changes in the gauge that controls drag on the Caravan. The trick to use invisible spoilers is a good one indeed, mostly because one can play with different flight and ground conditions.In this case, I added a polinomial that controls the increase of drag in a smooth way, taking into account the propeller status -if it's feathered, no drag at all-Also, as soon as the aicraft is landed, spoilers are removed as to extend the landing roll and improve the reverse throttle. On the other hand, a bit of spoilers are added in the take off roll, -up to 60 kias- as to extend the take off as well.All the variable values and triggers were estimated by me, who has no real Caravan flight experience so I'd be glad to send this gauge to anyone that would like to test it and help me find the most accurate behavior.Regards,Tom

Does the gauge you made, scale the simulated prop drag with the throttle position or the prop control?If you have been able to scale it with throttle control, then I would love to test it for ya.PM me if you still wanna send the gauge file out.JB

[pilotjohn 19]

Does the gauge you made, scale the simulated prop drag with the throttle position or the prop control?If you have been able to scale it with throttle control, then I would love to test it for ya.PM me if you still wanna send the gauge file out.JB

Same... why don't you attach it to a reply, so anyone can try it. Also, what do you use to edit gauge parameters and which gauge is it?

Sorry guys, time to throw my complete understanding of beta out the window : I just can't seem to wrap my head around the operated of free turboprops. I have a solid understanding of geard turbos, pistons and jets. I was recently on a Q400 and the FO told me that Beta was anywhere from flight idle and back (reverse) and alpha is anything from flight idle and forward...hmmm The reason I say never to put the 208 in beta is "a" because I had a completely different understanding of what beta wasy and "b" my friend flies a 208 for Fedex and he said that he would NEVER put it into beta during any stage of flight. But that could just be his SOP's.Could anyone fill me in on what beta is? :) Thanks!Regards,Cameron Caldwell.P.s. Sorry for stealing your thread pilotjohn

Regardless of what beta should or should not do on particular airplane, an F1 (idle detent on Saitek, 0 throttle value, no negatives) throttle setting should be considered "flight idle". Negative throttle settings (pressing F2 after pressing F1) can induce whatever logic might appropriate for beta range and associated reverse thrust. Beta range is nothing more than a near 0 to negative propeller blade angle that may or may not induce parachute-like drag (my guess is that it would not provide as much drag as real spoilers).