From: Simon J. M. <sim...@go...> - 2020-10-27 12:35:22
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Out of curiosity, I've had to create a pendulum damping force as a helicopter rotates around it's rotor, as opposed to it's CoG. Did anyone else have this issue, and how did you resolve it. Simon On Tue, 27 Oct 2020 at 09:40, Simon Julie Morley < sim...@go...> wrote: > Ok to answer the question about the tail rotor. > > It's a force that produces a moment equal and opposite to the main rotor > n_moment. The collective increases or reduces this force value by up to 10% > > On Tue, 27 Oct 2020, 00:56 Thomas, <kre...@mo...> wrote: > >> Hi Simon, >> >> sorry now for quoting into your response. >> >> Simon Julie Morley wrote: >> > No offense intended, it's not like I'm critising jsbsim as I'm using it. >> >> IMHO, youre welcome >> >> > >> > I chose to attempt to model a helicopter by adapting the propeller >> > code.... I shouldn't be critised for doing this. >> >> Well, call/interpretate the critism just as 'questions' about your >> intention, or simply as advice (you are trying something new, or?), >> since I guess the people in this forum all have their individual >> 'zugang' to jsbsim. >> >> > >> > This is my hobby, if you feel me doing something is a personal insult >> > and that we shouldn't talk about it, and that I shouldn't answer >> > questions raised to me then I'm at a loss as to the point of this >> forum.. >> >> No, again, feel free to exercise jsbsim -- but what's wrong about >> explaining what you like to do? My answer was a respose to your >> statement. Should I accept it, or should I pose a question? >> Alternatively, this could be a starting point for a discussion... >> >> Thomas >> >> >> > >> > Simon >> > >> > On Mon, 26 Oct 2020, 22:47 Thomas, <kre...@mo... >> > <mailto:kre...@mo...>> wrote: >> > >> > Hello Simon, >> > >> > I'm a bit offended by your claim -- CIT: 'there's nothing in it I >> can't >> > do with a propeller'. >> > >> > Allow me one question: how do you intend to treat the tail-rotor? >> > >> > Anyway, I'm curious about your results. 'think that the propeller is >> > better suited to model mid-size quad-drones and the like. >> > >> > Kind Regards, >> > >> > Thomas >> > >> > P.S. As for the rotor-model, two pointers for reading: >> > >> > /br/ >> > >> https://www.elsevier.com/books/bramwells-helicopter-dynamics/bramwell/978-0-08-097404-0 >> > >> > /sh/ Shaugnessy, J. D., Deaux, Thomas N., and Yenni, Kenneth R., >> > "Development and Validation of a Piloted Simulation of a Helicopter >> and >> > External Sling Load", NASA TP-1285, 1979 >> > >> > >> > Simon Julie Morley via Jsbsim-devel wrote: >> > > >> > > yeh I have, and there's nothing in it I can't do with a >> propeller, >> > > and actually there are things in the propeller code that the >> > rotor can't >> > > do.... so using rotor is a net less... >> > > >> > > Simon >> > > >> > > ---------- Forwarded message --------- >> > > From: *Sean McLeod* <se...@se... >> > <mailto:se...@se...> <mailto:se...@se... >> > <mailto:se...@se...>>> >> > > Date: Mon, 26 Oct 2020 at 20:00 >> > > Subject: RE: [Jsbsim-devel] Helicopter >> > > To: Simon Julie Morley <sim...@go... >> > <mailto:sim...@go...> >> > > <mailto:sim...@go... >> > <mailto:sim...@go...>>> >> > > >> > > >> > > Hi Simon____ >> > > >> > > __ __ >> > > >> > > Have you looked at the FGRotor code to see what helicopter >> specific >> > > stuff it models that isn’t modeled by FGPropeller?____ >> > > >> > > __ __ >> > > >> > > Cheers____ >> > > >> > > __ __ >> > > >> > > *From:* Simon Julie Morley <sim...@go... >> > <mailto:sim...@go...> >> > > <mailto:sim...@go... >> > <mailto:sim...@go...>>> >> > > *Sent:* Monday, October 26, 2020 5:19 PM >> > > *To:* Sean McLeod <se...@se... >> > <mailto:se...@se...> <mailto:se...@se... >> > <mailto:se...@se...>>> >> > > *Subject:* Re: [Jsbsim-devel] Helicopter____ >> > > >> > > __ __ >> > > >> > > Hi Sean,____ >> > > >> > > __ __ >> > > >> > > I'm not sure about using prop resulting in a lesser quality or >> that >> > > rotor offering greater functionality...____ >> > > >> > > __ __ >> > > >> > > I remain open minded to the possibilities____ >> > > >> > > __ __ >> > > >> > > Simon.____ >> > > >> > > __ __ >> > > >> > > On Mon, 26 Oct 2020, 13:08 Sean McLeod, <se...@se... >> > <mailto:se...@se...> >> > > <mailto:se...@se... <mailto:se...@se...>>> >> wrote:____ >> > > >> > > Hi Simon____ >> > > >> > > ____ >> > > >> > > I’m sure you can model a helicopter using FGPropeller etc. >> as a >> > > basis, but I would imagine it would be a 1^st order >> approximation >> > > since there are a number of dynamics that FGPropeller doesn’t >> > model >> > > compared to FGRotor, so FGRotor would more easily allow for a >> > higher >> > > fidelity model.____ >> > > >> > > ____ >> > > >> > > Cheers____ >> > > >> > > ____ >> > > >> > > *From:* Simon Julie Morley via Jsbsim-devel >> > > <jsb...@li... >> > <mailto:jsb...@li...> >> > > <mailto:jsb...@li... >> > <mailto:jsb...@li...>>> >> > > *Sent:* Sunday, October 25, 2020 11:59 PM >> > > *To:* Development issues <jsb...@li... >> > <mailto:jsb...@li...> >> > > <mailto:jsb...@li... >> > <mailto:jsb...@li...>>> >> > > *Cc:* Simon Julie Morley <sim...@go... >> > <mailto:sim...@go...> >> > > <mailto:sim...@go... >> > <mailto:sim...@go...>>> >> > > *Subject:* Re: [Jsbsim-devel] Helicopter____ >> > > >> > > ____ >> > > >> > > Hi Sean, ____ >> > > >> > > ____ >> > > >> > > To be honest I wanted to try and see if I could make a >> helicopter >> > > using the prop code, because I couldn't see why not.____ >> > > >> > > ____ >> > > >> > > On Sun, 25 Oct 2020 at 21:12, Sean McLeod >> > <se...@se... <mailto:se...@se...> >> > > <mailto:se...@se... <mailto:se...@se...>>> >> > wrote:____ >> > > >> > > Hi Simon____ >> > > >> > > ____ >> > > >> > > I’m just getting started again in terms of looking at >> JSBSim >> > > based helicopter models.____ >> > > >> > > ____ >> > > >> > > Thomas Kreitler improved the FGRotor model between 2010 – >> > 2012.____ >> > > >> > > ____ >> > > >> > > >> > >> https://github.com/JSBSim-Team/jsbsim/blob/4840a621dafe1ce64970990ddaec3e86a1c7e082/src/models/propulsion/FGRotor.cpp____ >> > > >> > > ____ >> > > >> > > He also added a fairly detailed helicopter model for the >> > AH1S:____ >> > > >> > > ____ >> > > >> > > >> > >> https://github.com/JSBSim-Team/jsbsim/tree/4840a621dafe1ce64970990ddaec3e86a1c7e082/aircraft/ah1s____ >> > > >> > > ____ >> > > >> > > In general there are very few JSBSim based helicopter >> models >> > > around when I last looked.____ >> > > >> > > ____ >> > > >> > > Cheers____ >> > > >> > > ____ >> > > >> > > *From:* Bill Galbraith <bil...@gm... >> > <mailto:bil...@gm...> >> > > <mailto:bil...@gm... >> > <mailto:bil...@gm...>>> >> > > *Sent:* Sunday, October 25, 2020 8:08 PM >> > > *To:* 'Development issues' >> > <jsb...@li... >> > <mailto:jsb...@li...> >> > > <mailto:jsb...@li... >> > <mailto:jsb...@li...>>> >> > > *Subject:* Re: [Jsbsim-devel] Helicopter____ >> > > >> > > ____ >> > > >> > > Simon,____ >> > > >> > > ____ >> > > >> > > I had devoted some brain cells towards that idea a while >> ago, >> > > but never implemented it.____ >> > > >> > > ____ >> > > >> > > Imagine a point mass, with a point vertical force located >> > above >> > > it. At 50% collective, vertical force equals weight. >> Cyclic >> > > tilts that vertical force fore/aft, left/right. >> > Displacing the >> > > cyclic yields a slight loss (sine of angle) loss of lift, >> > > requiring slightly more collective.____ >> > > >> > > ____ >> > > >> > > The painful part comes when you try to fly it with a >> > joystick. >> > > When you release the joystick, the cyclic returns back to >> > > neutral, the aircraft will slow to a hover. You basically >> > need a >> > > joystick that has a trim lever, or allows you to >> > reestablish the >> > > trim point.____ >> > > >> > > ____ >> > > >> > > Enough to get your brain cells excited?____ >> > > >> > > ____ >> > > >> > > Bill____ >> > > >> > > ____ >> > > >> > > *From:* Simon Julie Morley via Jsbsim-devel >> > > [mailto:jsb...@li... >> > <mailto:jsb...@li...>] >> > > *Sent:* Sunday, October 25, 2020 1:41 PM >> > > *To:* Development issues >> > <Jsb...@li... >> > <mailto:Jsb...@li...> >> > > <mailto:Jsb...@li... >> > <mailto:Jsb...@li...>>> >> > > *Cc:* Simon Julie Morley <sim...@go... >> > <mailto:sim...@go...> >> > > <mailto:sim...@go... >> > <mailto:sim...@go...>>> >> > > *Subject:* [Jsbsim-devel] Helicopter____ >> > > >> > > ____ >> > > >> > > Anyone here ever done one ?____ >> > > >> > > ____ >> > > >> > > Want to talk about it, share knowledge ?____ >> > > >> > > ____ >> > > >> > > Simon____ >> > > >> > > ____ >> > > >> > > ____ >> > > >> > > ____ >> > > >> > > _______________________________________________ >> > > Jsbsim-devel mailing list >> > > Jsb...@li... >> > <mailto:Jsb...@li...> >> > > <mailto:Jsb...@li... >> > <mailto:Jsb...@li...>> >> > > https://lists.sourceforge.net/lists/listinfo/jsbsim-devel >> > > _______________________________________________ >> > > The JSBSim Flight Dynamics Model project >> > > http://www.JSBSim.org >> > > ___________________________________________________ >> > > >> > > >> > > >> > > >> > > >> > > _______________________________________________ >> > > Jsbsim-devel mailing list >> > > Jsb...@li... >> > <mailto:Jsb...@li...> >> > > https://lists.sourceforge.net/lists/listinfo/jsbsim-devel >> > > _______________________________________________ >> > > The JSBSim Flight Dynamics Model project >> > > http://www.JSBSim.org >> > > _______________________________________________ >> > > >> > >> > -- >> > Thomas Kreitler - Information Retrieval >> > kre...@mo... <mailto:kre...@mo...> >> > 49/30/8413 1702 >> > >> >> -- >> Thomas Kreitler - Information Retrieval >> kre...@mo... >> 49/30/8413 1702 >> > |