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Showing results for tags 'flight model issue'.
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This has major implications on the flight model, to the point where the entire flight model could be considered incorrect. null This document has a lot of interesting information in it, but what we care about is this graph. This graph shows the relation between the position of the anti-torque pedals and the pitch of the blades of the tail rotor. It shows that at full left (0%), the tail rotor blades have a pitch of 18 degrees. It shows that centered (50%), the tail rotor blades have a pitch of 4 degrees. It shows that 65% from full left, the tail rotor blades have a pitch of 0 degrees, making no thrust. It shows that 100% from full left, the tail rotor blades have a pitch of -10.5 degrees, making nose right thrust. The DCS huey's tail rotor blades don't even come close to that. Here is a picture with the pedals full left. The blades have a pitch of about 22-25 degrees. Here is an image with the pedals centered. The blades have a pitch of about 10-12 degrees. Here is an image of the pedals all the way to the right. The blades have a pitch of about 0- -2 degrees, we'll assume 0 degrees and the camera isn't directly above the top of the blade so it looks a little angled. OK, so maybe you think it's just an animation error. I can prove that it is not. I can prove that is how it is modeled in the flight model. But first lets look at that graph again about 24% from full left (52% left of center) shows the blades at a pitch of around 10.5 degrees. 100% from full left (full right) shows the blades at a pitch of around 10.5 degrees in the other direction. With the helicopter stationary on the ground, either of these positions should place the exact same amount of stress on the driveshaft. This means that if we turn the governor off, both positions should reduce RPM by the same amount. Not even close. The bottom left example shows the pedals 25% from full left, considered 50% left of center, this means that the tail rotor blades will be at a SMALLER pitch than what full right should be, therefore should reduce RPM by LESS than the pedals full right would. The top middle example shows the pedals 100% from full left, all the way to the right, barely even touching the RPM, infact the RPM is slightly higher. The tail rotor, as modeled on the DCS UH-1H, is modeled incorrectly, not only visually, but also in terms of how it affects the flight model. The tail rotor is modeled as if full right pedal puts the blades at a pitch of 0 degrees. Producing no thrust. The repercussions of this encompass basically the entire flight model. With the tail rotor acting the way it does, it means that the phyiscal strength of relative torque values is entirely incorrect, and proper trim in a properly modeled aircraft would technically be impossible in some basic turns.
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I encountered this bug earlier, but didnt think anything of it until I read a post by Taerdyn in other topic. This bug has a couple of parts it seems. one is jettisoning stores can cause the airframe to start rolling uncontrollably, blacking the pilot out. Second part is after jettisons/dropping weapons, and rearming, it seems the weight of the airframe is being reduced by the weight of the stores you dropped. Attached is multiple logs and track files of the separate events. the final log is the one where the flight model got absolutely busted, and its a long one. it took time between take offs and landings to get the bug to really stand out. I've been able to reproduce this 100% of the time Towards the end, i could almost hover in the aircraft at about 30kias, and half throttle would catapult me to mach 1 at sea level almost instantly. dcs.log.old Drop tank bug f15.trk dcs.log Drop tank bug f15 2nd time.trk Jettison bug f15 part 2.trk f15 jettison fm bug.trk dcs Jettison.log
