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#4550427 - 01/02/21 12:44 AM Re: EECH 1.15.2 update available ***** [Re: thealx]  
Joined: Jun 2005
Posts: 2,132
Reticuli Offline
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Reticuli  Offline
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Joined: Jun 2005
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Dayton, OH, USA
I was wrong back then. Too hard to maintain lift with FM 2 in the latter mods. You should be able to safely maintain ground effect altitude (within 1/2 of the main rotor diameter from the ground) while at least well above translational lift speed (a minimum of double the ETL threshold velocity of 20kts on average, so about a minimum of 40kts) and on only one engine in a two engine helo at no higher than 100% torque on that remaining engine while gear is down. This is a US Army aviation requirement that it be able to get back to base on just one engine without starting the remaining engine on fire, etc. That's minimum. Sometimes quite a bit faster and out of ground effect is possible depending on the helo and/or loadout. Otherwise the extra engine is a waste of money if the helos can't. Only helos in EECH with FM 2 I think I can do that are the coaxials like the KA-52.

So the translational lift is obviously too weak and the engines are maybe slightly too weak with FM 2, as well. I wouldn't be surprised if ground effect is also too weak. The Comanche seems about 5 or 10 kts too slow max cruise speed in level flight at 100% torque with all engines operating, but Apache top speeds seem fine when both engines are still up. Hind is an unsafe pig. FM 0 is WAY too lite and powerful. FM 1 is slightly too much. Well over 100 kts out of ground effect on one remaining engine and with torque to spare on every helo? Yeah, 0 and 1 are off on that. FM 2 seems maybe to have gone too slow/heavy/weak, but, again, most (but not all) of it might just be the weak translational lift and ground effect.

As I said before, the automatic coordinated turning also starts mixing in yaw too much at too low a speed on 0 and 2 when you bank; it's off on 1, obviously, which isn't a bad compromise if it can't be fixed on the others.

Edit:

With FM 2, the menu option to disable Translational Lift is reversed. Off is on and on is off.

Putting the main rotor lift to at least dmrl=1.1 in the EECH.ini when FM 2 is in use seems to have met the minimum single-engine lift requirements for many of the helos just barely with an average loadout, without wildly increasing ceiling and top speed. In fact, it seems to approximate published Comanche dash speeds when briefly at 100% torque on two engines in level flight now. At dmrl=1.1 even the Hind can just barely make it back to base on one engine without starting on fire most of the time, which is a pretty good litmus test, I think. It's still a problem with max gross weight situations, though, and we'd need a jettison stores function for this alone to be sufficient. I suppose next is further dealing with the taxi wheel rolling problem, fixing the still-anemic translational & ground lifts and coaxial yaw rates, and raising the speed for when turn coordination begins kicking in remains on FM 2 to be at least as good as FM 0 & 1, but with the added nifty new RPM effects and proper turning at speed. I am also curious about what the global air density modifier does, as adjusting that solely before made zero difference on the IGE + ETL problem during failure of one of two engines that I could tell.

Last edited by Reticuli; 01/02/21 08:56 PM.

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#4565628 - 04/22/21 11:18 PM Re: EECH 1.15.2 update available [Re: thealx]  
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Reticuli Offline
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Reticuli  Offline
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Joined: Jun 2005
Posts: 2,132
Dayton, OH, USA
Originally Posted by thealx
ricnunes, what is really makes "problems" for you is transitional lift. lift gain instead of linearly increasing now has curve shape and has maximum value close to half of maximum helicopter velocity and will decrease with velocity increasing. so, if you flying at maximum speed you will experience lift loss. same for hovering and low speed moving, but usually ground effect makes it not very noticeable. just for testing purpose you can try to switch back to new FM and disable Transitional Lift in dynamics options.



When was this altered on FM 2? Where are these dynamics parameters and relationships located, because we haven't found them in the main source code files and these nuances are definitely not in the dyn files.


The term "necroposting" was invented by a person with no social memory beyond a year. People with a similar hangup are those o.k. with the internet being transient vapor.

http://www.openfuelstandard.org/2011/12/methanol-wins-open-wager.html

Saitek X65 and X52, Glide, Winx3D, and GlovePIE Profiles http://library.avsim.net/search.php?SearchTerm=reticuli&CatID=miscmisc

http://library.avsim.net/register.php

X52 + Silicone Grease = JOY stick
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