June 5, 201214 yr There is a very fine line between being very maneuverable, and being unstable Actually, in terms of "real" aircraft... the maneuverability of an aircraft can be based on the aircraft being inheritly unstable in one or more axes (modern fighters are the example I am thinking of). I do not agree that weight in and of itself gives you better stability... the fundamental importance of this weight would be its location. That will determine (longitudinal) stability... the CG and its location relative to the center of lift. You can have the same weight... but shifting it aft will markedly change control pressures required to the point which... e.g. if outside the aft cg location, the aircraft will become unstable and unable to recover from a stall / spin. I was thinking about your statement "More weight will make you more stable, since more force will be needed to push you off course"... which I got a kick out of as it reminded me of one turbulent night flight (more like night fright). This might be the case when jumping up significantly in aircraft types... like from the GA aircraft we are flying to corporate jets to the airline heavies... but within the category/class we are in... no... not so much. Go up on a significantly gusty day (approaching cold front) when the heavies are reporting 10 to 15kt loss of airpseed on final. You will find e.g. a Piper Arrow (and the few hundred pounds more or less that could be carried) means very little in terms of stability. What is more important are doing things like keeping a relatively high airspeed to maintain control effectiveness and positive control of the aircraft.
June 5, 201214 yr Commercial Member Lets not split hair on a beginners thread... Kevin Miller 3D Artist and developer
June 5, 201214 yr Lets not split hair on a beginners thread... You'll have to help me out here Kevin... as I have no clue what you are referring to.
June 5, 201214 yr Commercial Member We are getting to technical and off topic for the level of thread. She just wanted to know why she was curving to the left. Kevin Miller 3D Artist and developer
June 5, 201214 yr Well fwiw... as a certificated instructor, I do not feel any topics brought up in this thread (and few threads ever stay solely on topic) are past Private Pilot material. With all due respect Kevin... you discussed the topics of maneuverability and stability first. If you are referring to Weight & Balance (cg topic) that students will learn before Solo Cross-Country. But ok... back to the left turning tendency during takeoff... But from what I understand now during a takeoff roll it seems that the propwash would dominate? Aye... that is correct. Torque, P-Factor (asymmetric disk loading), Gyroscopic precession have all been blamed... and they do exist to varying degrees and times during the takeoff roll for a taildragger... but it is this "spiraling slipstream" (propwash) that is mainly attributed to being the cause of why one needs a significant amount right rudder (with a prop turning clockwise). Same effect occurs in tri-cycle gear aircraft, and can demand what feels like quite a bit of (right) rudder during the beginning of the takeoff until building up enough airspeed to compensate (air moving over the rudder). Rudders are generally trimmed out for cruise airspeeds... Does this mean that single turbines don't have a strong torque effect? I have absolutely zero time in turbine aircraft, so I really do hate to "answer" this question... however, since there would be no prop, therefore no propwash and the resulting effect(s) from it... I'd expect an F-86, F-16 etc. to track straight down the runway (no wind). Edit: referring to strictly a turbine (jet) engined aircraft... not meaning a turboprop like the Cessna 208 Caravan or Pilatus PC-12...
June 5, 201214 yr Rudders are generally trimmed out for cruise airspeeds... noffa, on 04 June 2012 - 11:00 PM, said: Does this mean that single turbines don't have a strong torque effect? I have absolutely zero time in turbine aircraft, so I really do hate to "answer" this question... however, since there would be no prop, therefore no propwash and the resulting effect(s) from it... I'd expect an F-86, F-16 etc. to track straight down the runway (no wind). Edit: referring to strictly a turbine (jet) engined aircraft... not meaning a turboprop like the Cessna 208 Caravan or Pilatus PC-12... Turboprops do "suffer" from both torque and slipstream effects. A Pilatus will add some p-factor too (although p-factor is usually negligible compared to the other players...). Regarding "pure" turbines, at least the F109 was known for the noticeable torque effects when the throttle was advanced to full/intercept climb power! The effect takes place only during the initial turbine acceleration of course... Eheh... Gliders do suffer from slipstream effects as well :-) With some tugs I do have to use a LOT of aileron/rudder to counteract slipstream from the tug plane! Flying gliders since 1980 Flightsimming since 1992 AMD Ryzen 5600x, 32GB RAM, GPU Nvidia RTX 3060 Ti 8 GB, 1 TB and 500 GB nvme2 SSD drives, HP 27" 60Hz LED monitor @ 1920x1080, T16000, Hotas from old X52 Pro, Saitek Combat Rudder Pro (2010 model)
June 5, 201214 yr Yeah, that's normally only on the tow before you get into the air though, and the tow rope tends to keep you pretty straight anyway. Every glider I've ever flown on an aerotow has been off the deck miles before the tow plane, to the extent that you have to hold it down at about 10 feet agl to stop the tow guy digging his prop in the ground, so you can actually take it above the worst of the wake, so long as you don't take it up too high LOL. Once you are in the air and out of ground effect, the wake from the tow plane is a long way below you. Anyhow, back on topic to the OP, glad you got it sorted out, and a belated welcome to the forums too. All that technical stuff about propwash and torque etc is just part of the fun of learning to fly an aeroplane. Al Alan Bradbury Check out my youtube flight sim videos: Here
June 5, 201214 yr Regarding "pure" turbines, at least the F109 was known for the noticeable torque effects when the throttle was advanced to full/intercept climb power! The effect takes place only during the initial turbine acceleration of course... Not sure what you mean by the F109, but.... This surprises me. I have turbine time in the T-2A Buckeye (single J34), T-2C Buckeye (two J85's), F-9 Cougar (single J48), and F-8 Crusader (single J57). All these aircraft had a rudder trim switch, but it was hardly ever touched. Rudder was used only for controlling weather-cocking on take-off roll, to actuate nose-wheel steering, and for banking the swept-wing Cougar and Crusader while pulling G's in ACM.
June 5, 201214 yr Not sure what you mean by the F109, but.... This surprises me Same here... i was thinking maybe he meant an F-106 and surprised me too... I would expect some torque effect (for any turbine for that matter) however I thought would be neglible in terms of stick and rudder forces. I have turbine time in USN or USMC? Edit: Disregard. Saw your (very impressive) bio at Loyola. :hand_salute: sir, from a crusty ol' ground poundin' devil dog.
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