Questions related to Flight Dynamics
I'm deeply interested in aerodynamics and CFD. I'm currently thinking about two masters:
_ one in aerospace dynamics which talk about flight mechanics, aerodynamics (lift, drag, flows characteristics ...) with modules about CFD, experimental aerodynamics (wind tunnel tests, measurements principles ).
_ CFD master which essentially talks about fluid mechanics, heat transfer, numerical methods, CAD, data analysis.
I want to become an aerodynamicist. I feel like the CFD master can give me a deeper understanding of fluid mechanics and more choices (I can work in fields like automotive, naval, aerospace). I'm more interested in aeronautics than other vehicles but it wouldn't bother to work for automobile or naval company. In the other hand the aerospace dynamics master is more centered on air-vehicles, can give me a good undertanding of flight dynamics and experimental skills not just numerical ones.
As I'm not experimented enough, I'm humbly asking which one do you think is the best for an aerodynamicist ?
I am in the preliminary design phase of a heavy-lift octocopter. Is there a systematic approach to selecting the proper propeller, motor, and battery for the given configuration provided that the frame size is still variable, the required payload weight is W and the endurance is T minutes?
All of the above parameters are coupled so I am guessing this will be an interactive solution. Any suggestions?
Thank you in advance for your advice and guidance,
1) What exactly is the definition of a control law and what is the difference between control laws and controllers in the context of aerospace vehicles ?
2) Is the use of the term flight control law specific only to aircraft (fixed wing & rotorcraft) and UAVs, for in my experience the term is not actively used in the context of Launch Vehicles or spacecraft ?
(examples of FCLAW's: images 1 and 2) 
A few questions regarding the control laws of combat aircraft -
3) The Eurofighter(EF 2000) seems to use an interesting control structure - the Differential PI Algorithm, which is also a controller that is being actively used by the naval version of the Indian LCA. My question is, as the controller seems to be quite advantageous, why has'nt the Differential PI structure been used in other flight controllers ? (refer to image 3)
4) The testing of combat flight control laws has made use of test aircraft for in-flight simulation, for example the use of the F-16 VISTA (now X-62 VISTA) to test flight control laws of the Indian LCA. How does this work ? How is useful information to validate & certify the control laws of one aircraft obtained from the flight performance and input responses using these same control laws but on another aircraft ? (refer: VISTA.pdf)
Note: This is not exclusive to aircraft as such, the control laws for the SLS have also been tested on an F/A 18 Hornet.
 Balas, Gary J.,"Flight Control Law Design - An industyr perspective", European Journal of Control, Vol. 9, Issues 2–3, 2003,
 Osterhuber, R., et.al."Realization of the Eurofighter 2000 Primary Lateral/Directional Flight Control Laws with Differential PI Algorithm", AIAA GNC Conference and Exhibit 16 - 19 August 2004, Providence, Rhode Island
 "Flight Testing of the Space Launch System (SLS) Adaptive Augmenting Control (AAC) Algorithm on an F/A-18", NASA/TM-2014-218528
Is there any public paper about the behaviour of a C* flight control system during stall entry and recovery?
It is my impression that an increasing number of airline passengers place cabin-sized suitcases in the overhead lockers.
1. Does anyone know whether there is an increased number of accidents from suitcases falling down when opening the overhead lockers?
2. Does it make a big difference for the pilots to fly the planes if most luggage is stored in the overhead lockers instead of the storage room? There are usually regulations in terms of number of items, size and weight of luggage declared as hand luggage, but what if these are not always adhered to?
Please I need a reference that could be used to build an aeroelastic model for an aircraft. The model should be simple, but yet accurate. It might be consisted of a simple aerodynamic model (lifting line, lifting surface, etc.) and a simple structural model (beam theory, etc.). The reference should give complete details and hands-on on how to build the model (not only theoretical derivations). The model should be fully implementable on MATLAB. It also needs to be finally represented in a state-space model that accounts for the ordinary rigid-body states, in addition to the flexible degrees of freedom. The results of the analytical model will be validated with real flight test data.
The aircraft to be modeled is a single-seated sailplane that has a wing span of 18 m, wing chord of 0.7 m, wing area of 11 m^2 and mass of 450 kg. The wing has low sweep and twist angles, and also a low tapering ratio with a considerable dihedral angle. The aircraft is constructed of composite materials (carbon fiber) and has a T-tail and ordinary control surfaces (aileron, elevator and rudder). The flight envelope is mainly characterized by altitudes up to 3 km and speeds from 100 to 160 km/h TAS.
The possibility of a mutual cooperation that will result in a published paper is also welcomed.
Towards solving Auto landing problem of a UAV what maneuvers carried out for heading correction along the runway by the autopilot. what are the path planning strategies.
For example, at what speed can the upper wing, fuselage cabin of an airplane be formed ?
I need to get an idea about speed scales ...
Thank you in advance.
I want to design a missile with tails while controlled with canard fins. The question is how to make the missile of critical damping in its pitch-mode response to the elevator (actuator-fin) deflection? I mean I want to meet a critically damped response of pitch-angle dynamics to canard-fin deflections (actuation). Although the missile is spinning but if you answer about spin-stabilized missile, your answer is also welcomed. I do not want any oscillatory motion in pitch-mode (only pure damping is sought). You can imagine rolling-airframe missile RIM116 as my design goal and reply with regard to that.
Recently, I have read some references applying proper orthogonal decomposition to solve unsteady aerodynamic problems. I'm very interested in this topic and really want to learn more about it. For now, I'm not sure how this method works, so, can anyone who is familiar with this topic give me some advice about starting in this field? Or some recommendations for related materials (books and references that may contain necessary mathematics background)? Thanks a lot!
PS: I'm familiar with linear algebra and basic matrix analysis, but I don't know much about control theory since I majored in aerodynamics.
At present i am using CAMRAD which does not address the subjected issue.
Since most of the theoretical and conceptual designs of Single Stage to Orbit (SSTO) aircraft are depicted through Scramjet-based vehicles (such as the X-30 concept from the National Aerospace Plane Program - https://en.wikipedia.org/wiki/Rockwell_X-30), would it actually be possible (and also economically feasible) to reach an orbit (at least a LEO-grade orbit) using an air-breathing engine as a Scramjet or even an hybrid approach like the Turboramjet in the SR-71 ?
If I were to design a cabin on top of the drone chassis which holds the cargo (say 15 kg), How should one go about designing the chassis? Should it be a monocoque, steel frame, unibody, body on frame structure?
This is important in my opinion as the chassis should hold the battery (primary structural member) and the electronics involved to control the propeller rotation and resulting thrust. I would love to get as many opinions and feedback as possible.
I´m trying to model the SH60 (sea hawk helicopter) on FLIGHTLAB, but the paper "PROCEDURAL GUIDE FOR MODELING AND ANALYZING THE FLIGHT DYNAMICS OF THE SH-60B HELICOPTER USING FLIGHTLAB" from Roy C. Wagner has some missing information about horizontal stabilizer tables. Is there somebody who can help me to find it?
Many models of this aircraft were developed, does somebody know a source for geometrical, aerodynamic, and mass characteristics?
I am trying to think of simple general modifications that can be done to a conventional type UAV so that it flies with better stability during crosswind of about 13m/s.
Does anyone know of any study that provides/obtains experimental values for the slipstream contraction factor, and for the slipstream heigth of a rotor? I am trying to modulate the slipstream using the expression V=Vc+Vi+Vi*tanh(s*k/h), from Seddon's Basic Helicopter Aerodynamics, but I am not finding a way to evaluate k (wake contraction factor) and h (slipstream height). I think I only need the value for the upper rotor, so values from a single rotor might work. And if they were regarding small propellers (unmanned aircraft prop) it would be better. I believe I can get a value for k from theoretical assumptions (as Leishman does), but if I would like to try with experimental values.
How much the friction between the aircrafts wheels and the runway during landing, participate to the rising of the runway surface temperature? is it something like %20 or 30% ….. of the actual temperature of the asphalt. I know it will be a function of the aircraft's landing rate plain weight, length of the runway, the weather and the seasons, wind speed and so on.
If you know any study have been carried out about this, any published paper or article that can be useful.
It could be related to fluid mechanics. To maintain the landing time, should i give more attention to lift or drag?
Any suggestion and opinion are welcomed. Thank you
Suppose, a simplified model of the roll dynamics of an aircraft, which is represented by xdot(t) = A x(t) + B u(t), where the states are (phi, p) and the u is the aileron command **(neglecting the dutch-roll mode).
Due the fact that, the controller contains an integral term, the system dynamics is augmented to contain the state related to the integral of the error signal. Let's call it of Tau(t). Then, we have [xdot Tau_dot] = A_aug x_aug(t) + B_aug u(t).
So, the control law is given by u(t) = - K x_aug + K(1) Phi(ref), where K is the static gain of the controller. Which we can "interpreted" as K = [Kp Kd Ki] = [Proportional, Derivative , Integral] (I have all states to feedback).
As the output of actuator is limited and the controller has an integral term, I should implement an Anti-windup scheme to avoid the windup of integral term. So, what type of anti-windup do you suggest?
Thanks in advance.
I am looking for papers/books presenting the regression equation between body size (body mass or wing length) and wingbeat frequency in hummingbirds. I'm aware of the two excellent publications below, and I try to get a hand on some of the old publications of Greenewalt, C. H.. Is there other publications that are addressing this relationship between body size and wingbeat frequencies in hummingbirds? I will need the regression equation to predict wingbeat frequency as a function of body size.
Altshuler, D. L., and Dudley, R. (2003). Kinematics of hovering hummingbird flight along simulated and natural elevational gradients. Journal of Experimental Biology 206, 3139-3147. doi:10.1242/jeb.00540
Altshuler, D. L., Dudley, R., Heredia, S. M., and McGuire, J. A. (2010). Allometry of hummingbird lifting performance. Journal of Experimental Biology 213, 725-734. doi:10.1242/jeb.037002
I just want to know what people usually do to measure the circulation or vortex strength in water or wind tunnel (like HWA or PIV, etc.), especially in some cases where the "boundary" of a vortex is not that clear, and the circulation can vary a lot when different boundaries are chosen. Sumner presented his data of circulation, sadly I didn't found his method of doing it in his paper. Here's Sumner's JFM paper: Sumner D, Price S J, Paidoussis M P. Flow-pattern identification for two staggered circular cylinders in cross-flow[J]. Journal of Fluid Mechanics, 2000, 411: 263-303.
hi dear researchers,
i want to model UAV aerodynamic,
i use relations in part 6 roskam or relation in performance books?
if any researcher have another source please send me.
see attachment please.
I have successfully come up with a new helicopter design that I call the NOTA MRH (NO TAil Mono Rotor Helicopter). The picture shows it's basic design. This helicopter does not need a tail rotor for torque reaction. The person flying this helicopter will only mind about the single main rotor cause that's the only rotor on the helicopter. It can work well for stealth helicopters. It is not a Mono copter or Coaxial helicopter nor Tandem helicopter and can easily be fitted in a space capsule if required for future landing.
How can the propeller slipstream-induced yawing effect on a General Aviation aircraft be estimated with only limited geometric information available?
Any references to existing literature dealing with this would be helpful.
For finding transfer function of aircraft we are finding 6 equations of motions then longitudinal and lateral equations of motions then linearization then statespace matrix then transfer function and used it in closed loop system
if we take a similar transfer function fraction equation as numerator and denominator of our own and use it in closed loop system
i mean to ask that if we take similar fraction or transfer function then simulate it in matlab the if we getting the approximate results when compared with original transfer function, then what is the use of dynamics why we working very hard for dynamics of aircraft and uav or quadrotor? is it just for sake of proof?but i think main thing is to design different controllers like linear and nonlinear controllers?
I am working on improving cockpit automation interfaces and will be using a PC based simulation as part of that effort. I am considering using Microsoft’s FSX, Flight Gear, X-Plane or Prepar3D. I’m leaning toward Flight Gear as it is open source and may be easier to develop interfaces with it using custom software. I wanted to ask other researchers what opinion they have regarding the suitability of these platforms for academic research especially when failure simulations will be created?
What is the highest wingbeat frequency (WBF) recorded for hummingbirds during hovering? To my knowledge the highest is 80 wingbeat per sec for the Bee hummingbird (Calypte helenae) (Greenewalt 1960). Are there publications that I'm not aware of with registrations of higher WBF for hummingbirds hovering?
There are well established manuals on flying/handling qualities for fixed-wing aircraft as well as for helicopters. Does anyone know if there exists similar documentation for the UAVs?
In designing flight control systems (FCS) for an air vehicle one has to consider HQ/FQ in order to meet specs of real FCS. Where can one see a set of HQ/FQ for all types of UAV (fixed wing, quad rotors, helicopters, etc.)?
I am trying to write a project proposal and I am having a problem referencing my proposal. Thing is I know things like dust etc can cause some damage to propellers which might lead to dents and cracks and etc, but what I need is research papers that prove this Where can I find them?
I'm looking for advice and references regarding the current state of the art for detecting landing and takeoff in fixed-wing micro UAVs. Hand launching is particularly of interest, as it is the most likely launch mode for micro UAVs.
Due to the low flight airspeeds of micro UAVs, pitot tube and GPS data are noisy and difficult to rely upon. One approach would be to add pressure sensors to detect contact with the ground or a human hand, but this is not an easily workable approach if cost, weight, and complexity are to be kept down. Ideally, we would like a generic implementation which uses the inertial gyroscopic and accelerometer sensors to detect takeoff and landing, but in my literature searches I haven't yet found anything along these lines.