Re: [Flightgear-devel] CH53e data
I just noticed that there might be/is a typo in the ch53e-yasim.xml file. change: ground-effect-constatnt="1.25" to: ground-effect-constant="1.25" Greetings, Wim On 1/3/07, wim van hoydonck <[EMAIL PROTECTED]> wrote: > Hi there, > > I just checked Janes' All the world aircraft (versions 1979-1880 and > 1989-1990) which confirms the data found in Prouty, except for the > main rotor blade twist. For thi,s Janes gives a value of -14 degrees, > but this value is probably measured from the root cutout (so not from > the centre of the hub as in Prouty). > > Performance data (ISA, T/O weight: 25400 kg) for the CH-53E: > - Max level speed @ S/L: 170 kts (315 km/h; 196 mph) > - Cruising speed @ S/L: 150 kts (272 km/h; 173 mph) > - Max Rate of Climb @ S/L:838 m (2750 ft) / sec > - Hovering ceiling IGE max power: 3520 m (11550 ft) > - Hovering ceiling OGE max power: 2895 m (9500 ft) > - Service ceiling max cont power: 5640m (18500 ft) > - Range (optim cruise speed for best range): 1120 nm (2075 km; 1290 miles) > > Powerplant > 3 T64-GE-415 or T64-GE-416 turboshaft engines; > - performance each: >- max rating: 3266 kW (4380 shp) 10 minutes >- intermediate rating:3091 kW (4145 shp) 30 minutes >- max cont rating: 2756 kW (3696 shp) > - rotor transmission: >- rated @ 9792 kW (13140 shp) for 10 sec >- rated @ 8627 kW (11570 shp) for 30 min > > Fuel capacity: > - self-sealing bladder fuel cell in forward part of each sponson, > each w. capacity of 1192 litres (315 US gallon) > - additional 2-cell unit, capacity 1465 litres (387 US gall), > -> total standard internal capacity: 3849 litres (1017 US gall) > - optional drop tanks outboard of each sponson for CH-53E, total > capacity 4921 litres (1300 US gall) > MH-53E can carry 7 internal range extension tanks, total capacity 7949 > litres (2100 US gall) > > Weights: > - empty:15 071 kg (33 226 lb) > - internal payload (100 nm radius): 13 607 kg (30 000 lb) > - external payload (50 nm radius): 14 605 kg (32 200 lb) > - MTOW: 33 339 kg (73500 lb) > > Rotor dimensions: > - MR diameter: 24.08 m > - TR diameter: 6.10 m > - MR blade chord: 0.76 m > - MR blade twist: 14 deg > > > Greetings, > > Wim > > > On 12/18/06, wim van hoydonck <[EMAIL PROTECTED]> wrote: > > Hi there, > > > > > > Some data for the CH53e yasim model, taken from Prouty [1], p. 699. > > > > Looking at the data in cvs, rotor diameters and chords should/could be > > changed, just like control input ranges for the main and tail rotor. > > > > > > Weights (lb): > > - Empty:33009 > > - MTOW (internal payload): 69750 > > - MTOW (external payload): 73500 > > - Fuel capacity (norm): 6682 > > - Fuel capacity (aux): 8450 > > > > Engines: > > - Type: General Electric T64-GE-416 > > - Number:3 > > - Max T.O. rating: 13140 > > - Max usable power: 11570 > > > > Rotor Parameters: Main > > Tail > > - Radius (ft): 39.5 > > 10 > > - Chord (ft):2.44 > > 1.28 > > - solidity 0.138 > > 0.163 > > - No. of blades: 7 > >4 > > - Tip speed (ft/sec):732 > > 733 > > - twist (deg): -20 > > -8 > > - equiv. linear hinge offset ration (e/R): 0.063 0.043 > > - Airfoil: SC1095 > >NACA 0015 > > - Collective range (deg): -1.4 to 19.6 -10 > > to 24 > > - Longitudinal cyclic range (deg): -8.5 to 18.0 - > > - Lateral cyclic range (deg): -9.8 to 6.1 - > > - Polar moment of inertia (slug ft^2) 51800181 > > > > > > Greetings, > > > > Wim > > > > > > [1] Prouty, R. W., Helicopter Performance, Stability and Control > > > > > > -- > > Avoid hangovers - stay drunk! > > > > > -- > Avoid hangovers - stay drunk! > -- Avoid hangovers - stay drunk! - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] CH53e data
Hi there, I just checked Janes' All the world aircraft (versions 1979-1880 and 1989-1990) which confirms the data found in Prouty, except for the main rotor blade twist. For thi,s Janes gives a value of -14 degrees, but this value is probably measured from the root cutout (so not from the centre of the hub as in Prouty). Performance data (ISA, T/O weight: 25400 kg) for the CH-53E: - Max level speed @ S/L: 170 kts (315 km/h; 196 mph) - Cruising speed @ S/L: 150 kts (272 km/h; 173 mph) - Max Rate of Climb @ S/L:838 m (2750 ft) / sec - Hovering ceiling IGE max power: 3520 m (11550 ft) - Hovering ceiling OGE max power: 2895 m (9500 ft) - Service ceiling max cont power: 5640m (18500 ft) - Range (optim cruise speed for best range): 1120 nm (2075 km; 1290 miles) Powerplant 3 T64-GE-415 or T64-GE-416 turboshaft engines; - performance each: - max rating: 3266 kW (4380 shp) 10 minutes - intermediate rating:3091 kW (4145 shp) 30 minutes - max cont rating: 2756 kW (3696 shp) - rotor transmission: - rated @ 9792 kW (13140 shp) for 10 sec - rated @ 8627 kW (11570 shp) for 30 min Fuel capacity: - self-sealing bladder fuel cell in forward part of each sponson, each w. capacity of 1192 litres (315 US gallon) - additional 2-cell unit, capacity 1465 litres (387 US gall), -> total standard internal capacity: 3849 litres (1017 US gall) - optional drop tanks outboard of each sponson for CH-53E, total capacity 4921 litres (1300 US gall) MH-53E can carry 7 internal range extension tanks, total capacity 7949 litres (2100 US gall) Weights: - empty:15 071 kg (33 226 lb) - internal payload (100 nm radius): 13 607 kg (30 000 lb) - external payload (50 nm radius): 14 605 kg (32 200 lb) - MTOW: 33 339 kg (73500 lb) Rotor dimensions: - MR diameter: 24.08 m - TR diameter: 6.10 m - MR blade chord: 0.76 m - MR blade twist: 14 deg Greetings, Wim On 12/18/06, wim van hoydonck <[EMAIL PROTECTED]> wrote: > Hi there, > > > Some data for the CH53e yasim model, taken from Prouty [1], p. 699. > > Looking at the data in cvs, rotor diameters and chords should/could be > changed, just like control input ranges for the main and tail rotor. > > > Weights (lb): > - Empty:33009 > - MTOW (internal payload): 69750 > - MTOW (external payload): 73500 > - Fuel capacity (norm): 6682 > - Fuel capacity (aux): 8450 > > Engines: > - Type: General Electric T64-GE-416 > - Number:3 > - Max T.O. rating: 13140 > - Max usable power: 11570 > > Rotor Parameters: Main Tail > - Radius (ft): 39.5 > 10 > - Chord (ft):2.44 > 1.28 > - solidity 0.138 > 0.163 > - No. of blades: 7 >4 > - Tip speed (ft/sec):732 > 733 > - twist (deg): -20 > -8 > - equiv. linear hinge offset ration (e/R): 0.063 0.043 > - Airfoil: SC1095 >NACA 0015 > - Collective range (deg): -1.4 to 19.6 -10 to > 24 > - Longitudinal cyclic range (deg): -8.5 to 18.0 - > - Lateral cyclic range (deg): -9.8 to 6.1 - > - Polar moment of inertia (slug ft^2) 51800181 > > > Greetings, > > Wim > > > [1] Prouty, R. W., Helicopter Performance, Stability and Control > > > -- > Avoid hangovers - stay drunk! > -- Avoid hangovers - stay drunk! - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] CH53e data
Hi, wim van hoydonck schrieb am 20.12.2006 21:48: >> If I got you correctly, the tip of the rotor for most helicopters has >> negative pitch at minimum collective (equal to the twist, e.g. -8.5° for >> the bo, -9 ... -12° for the ch47). >> > > Indeed. > > >> On ground most helicopters are parked >> with collective full down. Therefore it should be possible, to find >> pictures of helicopters with huge negative blade pitch on the tip of the >> rotor. Try to find such a photo for the bo or the ch47 ... >> > > Define "huge negative blade pitch angles". > With collective full down and approximately 10 degrees twist in > blades, the pitch of the blade tip will be in the order of 10 degrees > down. Not something I would call huge: > > http://www.airliners.net/open.file/1146481/M/ > http://www.airliners.net/open.file/0959909/M/ > http://www.airliners.net/open.file/1080345/M/ > http://www.airliners.net/open.file/1152408/M/ > > shows a puma and 3 chinook helicopter on the ground. Pitch angle at > the blades of these helis is in the order of 10 degrees nose down. > And for the front rotor of the chinook, you should take the high > forward tilt of the rotor itself into account when determining the > pitch angle of the retreating blade. > > Greetings, > > Wim > yes, you are right. Let me be a little bit more precise: ...Therefore it should be possible, to find pictures of helicopters with huge negative blade pitch on the tip of the rotor for all blades. If the stick is not centered, the pitch differs from blade to blade. At least on the first picture you can clearly see the pitch of the front-right blade to be positive. Maik - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] CH53e data
> If I got you correctly, the tip of the rotor for most helicopters has > negative pitch at minimum collective (equal to the twist, e.g. -8.5° for > the bo, -9 ... -12° for the ch47). Indeed. > On ground most helicopters are parked > with collective full down. Therefore it should be possible, to find > pictures of helicopters with huge negative blade pitch on the tip of the > rotor. Try to find such a photo for the bo or the ch47 ... Define "huge negative blade pitch angles". With collective full down and approximately 10 degrees twist in blades, the pitch of the blade tip will be in the order of 10 degrees down. Not something I would call huge: http://www.airliners.net/open.file/1146481/M/ http://www.airliners.net/open.file/0959909/M/ http://www.airliners.net/open.file/1080345/M/ http://www.airliners.net/open.file/1152408/M/ shows a puma and 3 chinook helicopter on the ground. Pitch angle at the blades of these helis is in the order of 10 degrees nose down. And for the front rotor of the chinook, you should take the high forward tilt of the rotor itself into account when determining the pitch angle of the retreating blade. Greetings, Wim On 12/20/06, Maik Justus <[EMAIL PROTECTED]> wrote: > Hi Wim, > wim van hoydonck schrieb am 19.12.2006 23:44: > > The minimum pitch angle at the blade root (or pitch bearing) for most > > helicopters is somewhere around 0 degrees, sometimes a bit more, > > sometimes a bit less. This is probably dictated by airworthiness > > requirements related to autorotational flight. If the pitch angle, and > > hence angle of attack would be too big during autorotation, drag on > > the blades would stop the blade in a matter of seconds, with > > not-too-nice consequences. > > > > > If I got you correctly, the tip of the rotor for most helicopters has > negative pitch at minimum collective (equal to the twist, e.g. -8.5° for > the bo, -9 ... -12° for the ch47). On ground most helicopters are parked > with collective full down. Therefore it should be possible, to find > pictures of helicopters with huge negative blade pitch on the tip of the > rotor. Try to find such a photo for the bo or the ch47 ... > > Maik > > - > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys - and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > ___ > Flightgear-devel mailing list > Flightgear-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/flightgear-devel > -- Avoid hangovers - stay drunk! - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] CH53e data
Hi Wim, wim van hoydonck schrieb am 19.12.2006 23:44: > The minimum pitch angle at the blade root (or pitch bearing) for most > helicopters is somewhere around 0 degrees, sometimes a bit more, > sometimes a bit less. This is probably dictated by airworthiness > requirements related to autorotational flight. If the pitch angle, and > hence angle of attack would be too big during autorotation, drag on > the blades would stop the blade in a matter of seconds, with > not-too-nice consequences. > > If I got you correctly, the tip of the rotor for most helicopters has negative pitch at minimum collective (equal to the twist, e.g. -8.5° for the bo, -9 ... -12° for the ch47). On ground most helicopters are parked with collective full down. Therefore it should be possible, to find pictures of helicopters with huge negative blade pitch on the tip of the rotor. Try to find such a photo for the bo or the ch47 ... Maik - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] CH53e data
On Tue, 19 Dec 2006, Maik Justus wrote: Important info for the ch47d flight model. I had expected a large delta3 effect. Can you point me to the point in the report, where you found this info? From the British ministry of defence: http://www.mod.uk/NR/rdonlyres/DB72A687-551F-498C-A402-A015E9C1CDDB/0/chinook_boeing1c.pdf (~2.5MB A report regarding the simulation of the accident. They mention several times that although the software used for the simulation is capable of taking delta3 into account, this is not used for the reason that there is no delta3 on the chinook helicopter.) Another little gem in the same collection (haven't seen this one before myself): http://www.mod.uk/NR/rdonlyres/8BF9CD63-D369-47AD-88A1-0117FEE32C01/0/chinook_boeing1b.pdf (a few diagrams of output from the simulation which gives away some data about the LCT algorithm -- it was 4°+4° after all. And Rotor thrust/torque in real units.) Now I'm confused about the LCT again. 4° relative what? "their respective masts"?? :P- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] CH53e data
Hi Maik, > the "incidence data I have for the bo" I mentioned is not the angle of > attack, but pitch or "the mechanical incidence angle". Ah, ok. That explains a lot :) > But with the > negative pitch you cited for the ch53e, the rotor would be able to > produce much "negative" force (as far as I know inly very few > helicopters are able to produce "negative forces", e.g. nh90 for carrier > operations, but not in flight). You would get much overspeed at descent. The minimum pitch angle at the blade root (or pitch bearing) for most helicopters is somewhere around 0 degrees, sometimes a bit more, sometimes a bit less. This is probably dictated by airworthiness requirements related to autorotational flight. If the pitch angle, and hence angle of attack would be too big during autorotation, drag on the blades would stop the blade in a matter of seconds, with not-too-nice consequences. > you mean 1 degree flap angle reduce the incidence by 0.45 degree? I > would to have to update the bo105.xml file then. Not exactly. See pp. 14-15 of [1]. 45 degrees pitch-flap coupling introduced through the control mechanism geometry reduces the blade pitch angle by 1 degree for every degree of blade flapping. So for normal helicopters, the blade flapping (coning angle) is somewhere around 5 degrees, resulting in a blade pitch reduction of 5 degrees. Adding pitch-flap coupling to the pitch equation gave a better match for the trim results, so it just seemed logical. Thesis, literature survey and a a3 page containing the source code structure can be found here (for now): http://users.pandora.be/tuinbels/afstuderen/ Note that the model described in my thesis has 9 structural degrees of freedom (6 for fuselage + coning angle, lateral and longitudinal tilt) and 4 (only inflow) or 8 (inflow and wake distortion dynamics) aerodynamic degrees of freedom, resulting in a total of 22 (or 26) states that have to be integrated each time step. Greetings, Wim PS My superviser used an analytical approach in calculating the rotor forces, her PhD thesis can be found here [2]. You might want to read that on too. [1] http://users.pandora.be/tuinbels/afstuderen/final_thesis.pdf [2] http://www.fmp.lr.tudelft.nl/content/phdthesis_mdpavel.pdf On 12/19/06, Maik Justus <[EMAIL PROTECTED]> wrote: > Hi Wim, > wim van hoydonck schrieb am 19.12.2006 11:31: > > Hi Maik, > > > > > >> yes, but it is still the double value than the bo. But the incidence > >> data I have for the bo is measured at 0.7r and therefore much smaller. > >> > > [...] > > > >> I am not sure if that matches the data. With 8° twist and -1.4° pitch at > >> minimum you will get -9.4° at the tip and something about -7° mean > >> (weightened with r^2). In autorotation you will get much overspeed. >The > >> data I have for the bo is measured at 0.7r. The effect is, that a pitch > >> of 0 degree gives approx. in the same lift as a blade without twist. > >> > > > > I think you are mixing incidence angle (angle of attack) with pitch angle > > here. > > > > > the "incidence data I have for the bo" I mentioned is not the angle of > attack, but pitch or "the mechanical incidence angle". But with the > negative pitch you cited for the ch53e, the rotor would be able to > produce much "negative" force (as far as I know inly very few > helicopters are able to produce "negative forces", e.g. nh90 for carrier > operations, but not in flight). You would get much overspeed at descent. > > [1] is appendix A of my MSc thesis (about helicopter flight dynamics > > modelling & simulation) > oh, can you mail me an copy of this thesis? > > in which the mathematical model of the main > > rotor is derived/explained. Figure A.2 contains a sideview of an > > airfoil along the span of a rotor blade, which should explain the > > difference between the two. > > > > The main contribution to the vertical component at a blade section > > (U_p in [1]) comes from the induced inflow. If the induced inflow is > > not calculated accurately (or not at all), the pitch angles at the > > blade sections will be much smaller than in reality, since inflow > > reduces the angles of attack. > > > > How is inflow calculated in Yasim? I only can find some reference to > > 'downwash', but I don't see any familiar equations overthere. > > > > > It follows an old theory of Prantl with an "empirical" correction > factor. (in function calculateAlpha in rotorpart.cpp) > >> One important point for the simulation: most rotors have a delta3 effect > >> (this means: reducing the pitch with increased flapping angle). Do you > >> know this parameter for the ch53e (or for other helicopter?) > >> > > > > At our faculty, we normally set delta_3 equal to -45 degrees for the > > bo105 (i.e. positive blade flapping reduces the blade pitch angle, so > > stabilizing). > you mean 1 degree flap angle reduce the incidence by 0.45 degree? I > would to have to update the bo105.xml file then. > > Pitch-flap coupling for the AS 330 Puma is zero
Re: [Flightgear-devel] CH53e data
Hi Wim, wim van hoydonck schrieb am 19.12.2006 11:31: > Hi Maik, > > >> yes, but it is still the double value than the bo. But the incidence >> data I have for the bo is measured at 0.7r and therefore much smaller. >> > [...] > >> I am not sure if that matches the data. With 8° twist and -1.4° pitch at >> minimum you will get -9.4° at the tip and something about -7° mean >> (weightened with r^2). In autorotation you will get much overspeed. >The >> data I have for the bo is measured at 0.7r. The effect is, that a pitch >> of 0 degree gives approx. in the same lift as a blade without twist. >> > > I think you are mixing incidence angle (angle of attack) with pitch angle > here. > > the "incidence data I have for the bo" I mentioned is not the angle of attack, but pitch or "the mechanical incidence angle". But with the negative pitch you cited for the ch53e, the rotor would be able to produce much "negative" force (as far as I know inly very few helicopters are able to produce "negative forces", e.g. nh90 for carrier operations, but not in flight). You would get much overspeed at descent. > [1] is appendix A of my MSc thesis (about helicopter flight dynamics > modelling & simulation) oh, can you mail me an copy of this thesis? > in which the mathematical model of the main > rotor is derived/explained. Figure A.2 contains a sideview of an > airfoil along the span of a rotor blade, which should explain the > difference between the two. > > The main contribution to the vertical component at a blade section > (U_p in [1]) comes from the induced inflow. If the induced inflow is > not calculated accurately (or not at all), the pitch angles at the > blade sections will be much smaller than in reality, since inflow > reduces the angles of attack. > > How is inflow calculated in Yasim? I only can find some reference to > 'downwash', but I don't see any familiar equations overthere. > > It follows an old theory of Prantl with an "empirical" correction factor. (in function calculateAlpha in rotorpart.cpp) >> One important point for the simulation: most rotors have a delta3 effect >> (this means: reducing the pitch with increased flapping angle). Do you >> know this parameter for the ch53e (or for other helicopter?) >> > > At our faculty, we normally set delta_3 equal to -45 degrees for the > bo105 (i.e. positive blade flapping reduces the blade pitch angle, so > stabilizing). you mean 1 degree flap angle reduce the incidence by 0.45 degree? I would to have to update the bo105.xml file then. > Pitch-flap coupling for the AS 330 Puma is zero. I am > not sure about other helicopters. > > > Greetings, > > Wim > > > Maik - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] CH53e data
Hi Joacim, Joacim Persson schrieb am 19.12.2006 02:39: > On Tue, 19 Dec 2006, Maik Justus wrote: > >> One important point for the simulation: most rotors have a delta3 effect >> (this means: reducing the pitch with increased flapping angle). Do you >> know this parameter for the ch53e (or for other helicopter?) >> > > I can only add that the CH-47D has no delta3 mechanism. > > (Or at least not the RAF HC Mk2 version which is very similar to the D > version Chinook. Found that out just now from reading the RAF > Mull-of-Kintyre accident report more thoroughly. But presumably this goes > for all Chinook production models.) > Important info for the ch47d flight model. I had expected a large delta3 effect. Can you point me to the point in the report, where you found this info? Thanks! Maik - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] CH53e data
Hi Maik, > yes, but it is still the double value than the bo. But the incidence > data I have for the bo is measured at 0.7r and therefore much smaller. [...] > I am not sure if that matches the data. With 8° twist and -1.4° pitch at > minimum you will get -9.4° at the tip and something about -7° mean >(weightened with r^2). In autorotation you will get much overspeed. >The >data I have for the bo is measured at 0.7r. The effect is, that a pitch >of 0 degree gives approx. in the same lift as a blade without twist. I think you are mixing incidence angle (angle of attack) with pitch angle here. [1] is appendix A of my MSc thesis (about helicopter flight dynamics modelling & simulation) in which the mathematical model of the main rotor is derived/explained. Figure A.2 contains a sideview of an airfoil along the span of a rotor blade, which should explain the difference between the two. The main contribution to the vertical component at a blade section (U_p in [1]) comes from the induced inflow. If the induced inflow is not calculated accurately (or not at all), the pitch angles at the blade sections will be much smaller than in reality, since inflow reduces the angles of attack. How is inflow calculated in Yasim? I only can find some reference to 'downwash', but I don't see any familiar equations overthere. > One important point for the simulation: most rotors have a delta3 effect > (this means: reducing the pitch with increased flapping angle). Do you > know this parameter for the ch53e (or for other helicopter?) At our faculty, we normally set delta_3 equal to -45 degrees for the bo105 (i.e. positive blade flapping reduces the blade pitch angle, so stabilizing). Pitch-flap coupling for the AS 330 Puma is zero. I am not sure about other helicopters. Greetings, Wim [1] http://users.pandora.be/tuinbels/afstuderen/appA.pdf On 12/19/06, Maik Justus <[EMAIL PROTECTED]> wrote: > Hi Wim > > wim van hoydonck schrieb am 18.12.2006 23:23: > > Hi Maik, > > > > > > Once our library opens again next year (they are moving to a new > > building), I'll cross check that data with Janes (I work at the > > faculty of aerospace engineering in Delft). > > > > > very good, thank you! > >> Very surprising for me are the > >> cyclic/ collective data with approx 20+18=38 degree maximum incidence of > >> the main rotor. > >> > > > > That's the maximum pitch angle at the root of the blade which is not > > the same as the angle of attack of a blade (element) along the span of > > the blade (inflow induced by the rotor itself reduces the angle of > > attack). > yes, but it is still the double value than the bo. But the incidence > data I have for the bo is measured at 0.7r and therefore much smaller. > > >> Unfortunately I do not have any information about the > >> airfoil (SC1095). > >> > > > > This ([1]) NASA report contains some data about wind tunnel test done > > with that airfoil. > > > > > Perfect. With this data I can calculate the data for the .xml file. > >> One important point: the main rotor and the tail rotor > >> are twisted. Do you know, where the incidence is measured? > >> > > > > Pitch angle (theta) is normally measured from the root of the blade, > > as can be seen in [2], page 322. > I am not sure if that matches the data. With 8° twist and -1.4° pitch at > minimum you will get -9.4° at the tip and something about -7° mean > (weightened with r^2). In autorotation you will get much overspeed. The > data I have for the bo is measured at 0.7r. The effect is, that a pitch > of 0 degree gives approx. in the same lift as a blade without twist. > > Flight path angle (phi) is calculated > > >from the tangential and normal velocity components at a blade element > > and the angle of attack (alpha) is the difference between (or sum of) > > these two (depending on the choice of positive axes). > > > > > >> Do you have such data for other helicopters in your book (bo105 (but > >> here the actual data should be correct), ec135, ec145, ch47d, s76c, > >> little nellie)? > >> > > > > I have access to the majority of editions of Janes All The Worlds > > Aircraft between 1976 and 2006, so yes :) (although I'm not sure > > about little nellie ...) > > > > > One important point for the simulation: most rotors have a delta3 effect > (this means: reducing the pitch with increased flapping angle). Do you > know this parameter for the ch53e (or for other helicopter?) > > > Greetings, > > > > Wim > > > > > > [1] http://halfdome.arc.nasa.gov/publications/files/NASA-TP-2003-212265.pdf > > [2] > > http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19960054374_1996092848.pdf > > > > > > > Thank you, > Maik > > - > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys - and earn cash > http://www.techsay.com/default.php?page=j
Re: [Flightgear-devel] CH53e data
On Tue, 19 Dec 2006, Maik Justus wrote: > One important point for the simulation: most rotors have a delta3 effect > (this means: reducing the pitch with increased flapping angle). Do you > know this parameter for the ch53e (or for other helicopter?) I can only add that the CH-47D has no delta3 mechanism. (Or at least not the RAF HC Mk2 version which is very similar to the D version Chinook. Found that out just now from reading the RAF Mull-of-Kintyre accident report more thoroughly. But presumably this goes for all Chinook production models.) - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] CH53e data
Hi Wim wim van hoydonck schrieb am 18.12.2006 23:23: > Hi Maik, > > > Once our library opens again next year (they are moving to a new > building), I'll cross check that data with Janes (I work at the > faculty of aerospace engineering in Delft). > > very good, thank you! >> Very surprising for me are the >> cyclic/ collective data with approx 20+18=38 degree maximum incidence of >> the main rotor. >> > > That's the maximum pitch angle at the root of the blade which is not > the same as the angle of attack of a blade (element) along the span of > the blade (inflow induced by the rotor itself reduces the angle of > attack). yes, but it is still the double value than the bo. But the incidence data I have for the bo is measured at 0.7r and therefore much smaller. >> Unfortunately I do not have any information about the >> airfoil (SC1095). >> > > This ([1]) NASA report contains some data about wind tunnel test done > with that airfoil. > > Perfect. With this data I can calculate the data for the .xml file. >> One important point: the main rotor and the tail rotor >> are twisted. Do you know, where the incidence is measured? >> > > Pitch angle (theta) is normally measured from the root of the blade, > as can be seen in [2], page 322. I am not sure if that matches the data. With 8° twist and -1.4° pitch at minimum you will get -9.4° at the tip and something about -7° mean (weightened with r^2). In autorotation you will get much overspeed. The data I have for the bo is measured at 0.7r. The effect is, that a pitch of 0 degree gives approx. in the same lift as a blade without twist. > Flight path angle (phi) is calculated > >from the tangential and normal velocity components at a blade element > and the angle of attack (alpha) is the difference between (or sum of) > these two (depending on the choice of positive axes). > > >> Do you have such data for other helicopters in your book (bo105 (but >> here the actual data should be correct), ec135, ec145, ch47d, s76c, >> little nellie)? >> > > I have access to the majority of editions of Janes All The Worlds > Aircraft between 1976 and 2006, so yes :) (although I'm not sure > about little nellie ...) > > One important point for the simulation: most rotors have a delta3 effect (this means: reducing the pitch with increased flapping angle). Do you know this parameter for the ch53e (or for other helicopter?) > Greetings, > > Wim > > > [1] http://halfdome.arc.nasa.gov/publications/files/NASA-TP-2003-212265.pdf > [2] > http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19960054374_1996092848.pdf > > > Thank you, Maik - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] CH53e data
Hi Maik, Once our library opens again next year (they are moving to a new building), I'll cross check that data with Janes (I work at the faculty of aerospace engineering in Delft). > Very surprising for me are the > cyclic/ collective data with approx 20+18=38 degree maximum incidence of > the main rotor. That's the maximum pitch angle at the root of the blade which is not the same as the angle of attack of a blade (element) along the span of the blade (inflow induced by the rotor itself reduces the angle of attack). You would only need that combination in high speed forward flight, which in normal flight is limited by the stall on the inner side of the retreating blade. > Unfortunately I do not have any information about the > airfoil (SC1095). This ([1]) NASA report contains some data about wind tunnel test done with that airfoil. > One important point: the main rotor and the tail rotor > are twisted. Do you know, where the incidence is measured? Pitch angle (theta) is normally measured from the root of the blade, as can be seen in [2], page 322. Flight path angle (phi) is calculated from the tangential and normal velocity components at a blade element and the angle of attack (alpha) is the difference between (or sum of) these two (depending on the choice of positive axes). > Do you have such data for other helicopters in your book (bo105 (but > here the actual data should be correct), ec135, ec145, ch47d, s76c, > little nellie)? I have access to the majority of editions of Janes All The Worlds Aircraft between 1976 and 2006, so yes :) (although I'm not sure about little nellie ...) Greetings, Wim [1] http://halfdome.arc.nasa.gov/publications/files/NASA-TP-2003-212265.pdf [2] http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19960054374_1996092848.pdf On 12/18/06, Maik Justus <[EMAIL PROTECTED]> wrote: > Hi Wim, > > very interesting data. I have googled to find out, which values are > correct, at least for the rotor diameter there is many data on the net. > It seems, that in the version in cvs some data are from the ch53d (or > are there different ch53e variants?). Very surprising for me are the > cyclic/ collective data with approx 20+18=38 degree maximum incidence of > the main rotor. Unfortunately I do not have any information about the > airfoil (SC1095). One important point: the main rotor and the tail rotor > are twisted. Do you know, where the incidence is measured? > > Do you have such data for other helicopters in your book (bo105 (but > here the actual data should be correct), ec135, ec145, ch47d, s76c, > little nellie)? > > Thank you, > Maik > wim van hoydonck schrieb am 18.12.2006 15:49: > > Hi there, > > > > > > Some data for the CH53e yasim model, taken from Prouty [1], p. 699. > > > > Looking at the data in cvs, rotor diameters and chords should/could be > > changed, just like control input ranges for the main and tail rotor. > > > > > > Weights (lb): > > - Empty:33009 > > - MTOW (internal payload): 69750 > > - MTOW (external payload): 73500 > > - Fuel capacity (norm): 6682 > > - Fuel capacity (aux): 8450 > > > > Engines: > > - Type: General Electric T64-GE-416 > > - Number:3 > > - Max T.O. rating: 13140 > > - Max usable power: 11570 > > > > Rotor Parameters: Main > > Tail > > - Radius (ft): 39.5 > > 10 > > - Chord (ft):2.44 > > 1.28 > > - solidity 0.138 > > 0.163 > > - No. of blades: 7 > >4 > > - Tip speed (ft/sec):732 > > 733 > > - twist (deg): -20 > > -8 > > - equiv. linear hinge offset ration (e/R): 0.063 0.043 > > - Airfoil: SC1095 > >NACA 0015 > > - Collective range (deg): -1.4 to 19.6 -10 > > to 24 > > - Longitudinal cyclic range (deg): -8.5 to 18.0 - > > - Lateral cyclic range (deg): -9.8 to 6.1 - > > - Polar moment of inertia (slug ft^2) 51800181 > > > > > > Greetings, > > > > Wim > > > > > > [1] Prouty, R. W., Helicopter Performance, Stability and Control > > > > > > > > > - > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys - and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > ___ > Flightgear-devel mailing list > Flight
Re: [Flightgear-devel] CH53e data
Hi Wim, very interesting data. I have googled to find out, which values are correct, at least for the rotor diameter there is many data on the net. It seems, that in the version in cvs some data are from the ch53d (or are there different ch53e variants?). Very surprising for me are the cyclic/ collective data with approx 20+18=38 degree maximum incidence of the main rotor. Unfortunately I do not have any information about the airfoil (SC1095). One important point: the main rotor and the tail rotor are twisted. Do you know, where the incidence is measured? Do you have such data for other helicopters in your book (bo105 (but here the actual data should be correct), ec135, ec145, ch47d, s76c, little nellie)? Thank you, Maik wim van hoydonck schrieb am 18.12.2006 15:49: > Hi there, > > > Some data for the CH53e yasim model, taken from Prouty [1], p. 699. > > Looking at the data in cvs, rotor diameters and chords should/could be > changed, just like control input ranges for the main and tail rotor. > > > Weights (lb): > - Empty:33009 > - MTOW (internal payload): 69750 > - MTOW (external payload): 73500 > - Fuel capacity (norm): 6682 > - Fuel capacity (aux): 8450 > > Engines: > - Type: General Electric T64-GE-416 > - Number:3 > - Max T.O. rating: 13140 > - Max usable power: 11570 > > Rotor Parameters: Main Tail > - Radius (ft): 39.5 > 10 > - Chord (ft):2.44 > 1.28 > - solidity 0.138 > 0.163 > - No. of blades: 7 >4 > - Tip speed (ft/sec):732 > 733 > - twist (deg): -20 > -8 > - equiv. linear hinge offset ration (e/R): 0.063 0.043 > - Airfoil: SC1095 >NACA 0015 > - Collective range (deg): -1.4 to 19.6 -10 to > 24 > - Longitudinal cyclic range (deg): -8.5 to 18.0 - > - Lateral cyclic range (deg): -9.8 to 6.1 - > - Polar moment of inertia (slug ft^2) 51800181 > > > Greetings, > > Wim > > > [1] Prouty, R. W., Helicopter Performance, Stability and Control > > > - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
[Flightgear-devel] CH53e data
Hi there, Some data for the CH53e yasim model, taken from Prouty [1], p. 699. Looking at the data in cvs, rotor diameters and chords should/could be changed, just like control input ranges for the main and tail rotor. Weights (lb): - Empty:33009 - MTOW (internal payload): 69750 - MTOW (external payload): 73500 - Fuel capacity (norm): 6682 - Fuel capacity (aux): 8450 Engines: - Type: General Electric T64-GE-416 - Number:3 - Max T.O. rating: 13140 - Max usable power: 11570 Rotor Parameters: Main Tail - Radius (ft): 39.5 10 - Chord (ft):2.44 1.28 - solidity 0.138 0.163 - No. of blades: 7 4 - Tip speed (ft/sec):732 733 - twist (deg): -20 -8 - equiv. linear hinge offset ration (e/R): 0.063 0.043 - Airfoil: SC1095 NACA 0015 - Collective range (deg): -1.4 to 19.6 -10 to 24 - Longitudinal cyclic range (deg): -8.5 to 18.0 - - Lateral cyclic range (deg): -9.8 to 6.1 - - Polar moment of inertia (slug ft^2) 51800181 Greetings, Wim [1] Prouty, R. W., Helicopter Performance, Stability and Control -- Avoid hangovers - stay drunk! - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
