takefootoff Posted October 6, 2018 Report Share Posted October 6, 2018 Coming from Bell products, love having a trim string again. Is trim accomplished with the string lined up straight with the center pillar, or is it offset and pointed towards the pilot? My lower back used to let me know if I was in trim or not, but I'm just generally sore and numb now so I'm having a hard time sensing it. 1 Quote Link to comment Share on other sites More sharing options...
V-any Posted October 6, 2018 Report Share Posted October 6, 2018 Coming from Bell products, love having a trim string again. Is trim accomplished with the string lined up straight with the center pillar, or is it offset and pointed towards the pilot? My lower back used to let me know if I was in trim or not, but I'm just generally sore and numb now so I'm having a hard time sensing it. It's just a piece of yarn. When when the wind is directly from the front, it pushes the yarn directly aft, and it's in trim. Quote Link to comment Share on other sites More sharing options...
takefootoff Posted October 6, 2018 Author Report Share Posted October 6, 2018 That piece of yarn has a part number too. Quote Link to comment Share on other sites More sharing options...
Wally Posted October 6, 2018 Report Share Posted October 6, 2018 Coming from Bell products, love having a trim string again. Is trim accomplished with the string lined up straight with the center pillar, or is it offset and pointed towards the pilot? My lower back used to let me know if I was in trim or not, but I'm just generally sore and numb now so I'm having a hard time sensing it. The inclinometer's ball is set at 'level' in the roll axis. The aircraft does not fly level in roll, from a pronounced right side down at a hover, gradually bringing the right side up at speed, according to cg, power, weight and speed.The 'string' on the nose cone accurately shows air flow streamline, I consider(ed) it primary, and calibrated my 'ball' by it.Yes, it has a part number and is required for airworthiness. I don't remember being certified to replace it, but having a spare in your RFM, or personal kit is a good idea....The final authority is whether the aircraft holds heading. If it wander off, right or left, I re-calibrate everything.The aircraft is pretty stable at speed, pitch, roll and yaw, but it becomes faster as fuel burns,and that affects everything else. I always cruise(d) at max continuous, fuel is cheaper than fight time, so all speed available is economic. 1 Quote Link to comment Share on other sites More sharing options...
takefootoff Posted October 7, 2018 Author Report Share Posted October 7, 2018 So it's just straight up the pipe then? Was probably just over thinking it, something about how the pilot seat is slightly crossed in or maybe I'm a lil cross eyed. Quote Link to comment Share on other sites More sharing options...
brettjeepski Posted October 8, 2018 Report Share Posted October 8, 2018 So it's just straight up the pipe then? Was probably just over thinking it, something about how the pilot seat is slightly crossed in or maybe I'm a lil cross eyed.No I would say straight at your head. Not inline with the pillar. Quote Link to comment Share on other sites More sharing options...
Azhigher Posted October 8, 2018 Report Share Posted October 8, 2018 I usually shoot for straight up the pillar. Not sure if that's the "correct" answer, but it's what I do. Regardless of what I do though my mechanic will tell me I'm using too much pedal and I'm wearing down the bearings prematurely. 1 Quote Link to comment Share on other sites More sharing options...
Eric Hunt Posted October 8, 2018 Report Share Posted October 8, 2018 No I would say straight at your head. Not inline with the pillar.This would have totally different results if you sat in the other seat.Gotta be Wrong.Straight up. Airflow is then balanced either side. That's why they call it "balance". Quote Link to comment Share on other sites More sharing options...
takefootoff Posted October 9, 2018 Author Report Share Posted October 9, 2018 (edited) Fellas, please. I really have no clue on this one. I'll get it cruising straight and level tap each of the pedals (slightly) and it still won't feel 'right. Got an Aspen MFD/PFD installed and I don't trust anything that thing says. My back still hurts at the end of the day. Edited October 9, 2018 by takefootoff Quote Link to comment Share on other sites More sharing options...
V-any Posted October 9, 2018 Report Share Posted October 9, 2018 Neither the inclinometer nor the Aspen will tell you if the helicopter is in trim. Only the string will. The string points straight back when it's in trim. This was answered in the first reply. Everyone pay attention: ... It's just a string. Not a magical string that knows where the pilot sits and points to him when it's in trim, it's just a damn string. When air hits it from the front, it points aft. When air hits it from the side, it points to the opposite side. ... sometimes helicopter pilots amaze me. 1 Quote Link to comment Share on other sites More sharing options...
WolftalonID Posted October 9, 2018 Report Share Posted October 9, 2018 The aspens inclometer should be accurate for trim if installed properly. Quote Link to comment Share on other sites More sharing options...
Azhigher Posted October 9, 2018 Report Share Posted October 9, 2018 My back still hurts at the end of the day. Oh buddy, if that's your judge of trim I've been out of trim since flight school. 4 Quote Link to comment Share on other sites More sharing options...
V-any Posted October 9, 2018 Report Share Posted October 9, 2018 The aspens inclometer should be accurate for trim if installed properly. Trim and balance (ball in the center) are two different things. 1 Quote Link to comment Share on other sites More sharing options...
supergokougt Posted October 9, 2018 Report Share Posted October 9, 2018 Fellas, please. I really have no clue on this one. I'll get it cruising straight and level tap each of the pedals (slightly) and it still won't feel 'right. Got an Aspen MFD/PFD installed and I don't trust anything that thing says. My back still hurts at the end of the day. If back pain an issue I got the relaxoback seat and lumbar pillow to help with back pain after hours in a B2. And really try and keep that back straight. Really helped with the shifting in the seat after about 2 hours. https://www.amazon.com/RelaxoBak-Support-Tailbone-Orthopedic-Cushion/dp/B001OVFNQA/ref=sr_1_2_a_it?ie=UTF8&qid=1539110514&sr=8-2&keywords=relax+o+back 1 Quote Link to comment Share on other sites More sharing options...
Wally Posted October 9, 2018 Report Share Posted October 9, 2018 My back still hurts at the end of the day. That's mandatory in helicopters, isn't it? Better seats help. The older Astar fiberglass bucket seats were the worst I sat in over 48 years of flying. The newer, energy attenuating seats were much better. Quote Link to comment Share on other sites More sharing options...
Hand_Grenade_Pilot Posted October 10, 2018 Report Share Posted October 10, 2018 Youre overthinking it mate. Just fly what feels right. I hated having a trim string on the AS350. It annoyed the hell out of me. As silly as it sounds, I just didnt like seeing a little wire sticking out with a string. A weird pet peeve I guess. I would keep the wire in the little hook so I wouldnt have to look at it. Every time ground crew came over to hot load, they thought I had forgot to unhook the trim wire during preflight; as theyd reach to unhook it Id try to wave them off only to get a confused look. 1 Quote Link to comment Share on other sites More sharing options...
takefootoff Posted October 10, 2018 Author Report Share Posted October 10, 2018 Would ya'l consider me crazy if I'd say trim at night feels different than trim in the daylight? Quote Link to comment Share on other sites More sharing options...
takefootoff Posted October 10, 2018 Author Report Share Posted October 10, 2018 (edited) No I would say straight at your head. Not inline with the pillar.I'm kinda with you on this one man, straight and level, 70% trq or so, little bit of left pedal and right cyclic 'feels' right (correct) trim string slightly pointed at my dome... Or is it the other way around? Oh gosh. Edited October 10, 2018 by takefootoff 1 Quote Link to comment Share on other sites More sharing options...
takefootoff Posted October 10, 2018 Author Report Share Posted October 10, 2018 Youre overthinking it mate. Just fly what feels right. I hated having a trim string on the AS350. It annoyed the hell out of me. As silly as it sounds, I just didnt like seeing a little wire sticking out with a string. A weird pet peeve I guess. I would keep the wire in the little hook so I wouldnt have to look at it. Every time ground crew came over to hot load, they thought I had forgot to unhook the trim wire during preflight; as theyd reach to unhook it Id try to wave them off only to get a confused look.Dunno if it's a curse or a blessing at this point, was awfully keen on getting over the 'Bell back' transitioning into the squirrel. Time will tell. Quote Link to comment Share on other sites More sharing options...
Eric Hunt Posted October 10, 2018 Report Share Posted October 10, 2018 The worst Bell Back is from the Huey - sitting on a sagging mesh seat, leaning slightly left to reach the collective, hunched forward after several hours of hash-and-trash, head tilted upward to see over the instrument coaming, and the helmet adding some weight, and getting bounced up and down with the famous Huey 1:1 wok wok wok. No wonder I have neck problems and a back that does not tolerate sitting still very long. Quote Link to comment Share on other sites More sharing options...
iChris Posted October 11, 2018 Report Share Posted October 11, 2018 (edited) Coming from Bell products, love having a trim string again. Is trim accomplished with the string lined up straight with the center pillar, or is it offset and pointed towards the pilot? My lower back used to let me know if I was in trim or not, but I'm just generally sore and numb now so I'm having a hard time sensing it. The string lined up straight with the center pillar is your best option for the least amount of drag in forward flight. Your slip ball measures only the aircraft’s lateral balance resulting from the forces of gravity and centripetal force. You can observe this fact by holding your helicopter in a hover over a spot where the helicopter is neither moving laterally or vertically and noting the position of the ball. It will be off to one side of center. This is all due to the fact that the helicopter is an aerodynamic beast affected by both inertia forces and aerodynamic forces. The ball’s position is affected only by inertia forces (gravity and centripetal force, if any). You’ll have an offset lateral CG, offset from the vertical axis of the helicopter, due to any aerodynamic moment created by the tail rotor thrust, main rotor tilt, and or vertical stabilizer forces, which are the source of the “inherent sideslip” that all helicopters with a tail rotor experience when flown in ball-centered, straight and level flight. With the string lined up straight with the center pillar in forward flight, you may note that your slip ball is nearly in the same position it was in the hover described above when you were in a stationary hover and the helicopter was in equilibrium aerodynamically. Again, the string is your best option for the least amount of drag in forward flight with the aircraft in-line with the relative wind. In any case, you may still have 1 to 2 degrees of “inherent sideslip” which is a characteristic attributed to most single rotor helicopters with a tail rotor. Fuselage left tilt as shown above, counter-clockwise turning main rotor. Fuselage right tilt on clockwise turning main rotor. As viewed from the top. Edited October 25, 2018 by iChris Quote Link to comment Share on other sites More sharing options...
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