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Re: [Jsbsim-devel] Fwd: Helicopter
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From: Simon J. M. <sim...@go...> - 2020-10-30 09:39:57
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Come on, it wasn't that hard a question On Tue, 27 Oct 2020 at 15:54, Simon Julie Morley < sim...@go...> wrote: > I'm not a C++ coder I work on xml code. > > It's not a case of ignoring rotor functionality but more a case of after > 10+ years of only working on propellers, (in fact the first time i touched > a turbine was doing the avatar Scorpion gunship) I'm extremely familiar > with how the to create propeller tables and how the propeller code works. > > To answer the next question, without using any equations describe in your > own words the requirements of, and how flapping is implemented in a real > life helicopter and I'll explain how I do it with a prop. > > Simon > > On Tue, 27 Oct 2020 at 13:50, Sean McLeod <se...@se...> wrote: > >> Hi Simon >> >> >> >> Are you adding code to FGPropeller to implement some of the functionality >> that is currently in FGRotor but not in FGPropeller currently? >> >> >> >> Are there some aspects of FGRotor’s functionality that you’re ignoring >> because you don’t think they’re useful for your needs? >> >> >> >> What things did you notice in FGPropeller that FGRotor can’t currently >> do? Could potentially be useful to add them to FGRotor for users of FGRotor. >> >> >> >> What’s quite useful is Thomas references the equations etc. that his code >> is based on, e.g. >> >> >> >> // Flapping angles relative to control axes /SH79/ eqn(32) >> >> void FGRotor::calc_flapping_angles(double theta_0, const FGColumnVector3 >> &pqr_fus_w) >> >> >> >> <dt>/SH79/</dt><dd>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.</dd> >> >> >> >> https://ntrs.nasa.gov/citations/19790005912 >> >> >> >> I’m currently using FGotor for the helicopter models I’m working on so >> I’d be interested to know what you see as the pros and cons of using >> FGRotor versus FGPropeller. >> >> >> >> Cheers >> >> >> >> *From:* Simon Julie Morley via Jsbsim-devel < >> jsb...@li...> >> *Sent:* Monday, October 26, 2020 10:09 PM >> *To:* Development issues <Jsb...@li...> >> *Cc:* Simon Julie Morley <sim...@go...> >> *Subject:* [Jsbsim-devel] Fwd: Helicopter >> >> >> >> >> 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...> >> Date: Mon, 26 Oct 2020 at 20:00 >> Subject: RE: [Jsbsim-devel] Helicopter >> To: Simon Julie Morley <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...> >> *Sent:* Monday, October 26, 2020 5:19 PM >> *To:* Sean McLeod <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...> 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 1st 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...> >> *Sent:* Sunday, October 25, 2020 11:59 PM >> *To:* Development issues <jsb...@li...> >> *Cc:* Simon Julie Morley <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...> 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...> >> *Sent:* Sunday, October 25, 2020 8:08 PM >> *To:* 'Development issues' <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... >> <jsb...@li...>] >> *Sent:* Sunday, October 25, 2020 1:41 PM >> *To:* Development issues <Jsb...@li...> >> *Cc:* Simon Julie Morley <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... >> https://lists.sourceforge.net/lists/listinfo/jsbsim-devel >> _______________________________________________ >> The JSBSim Flight Dynamics Model project >> http://www.JSBSim.org >> _______________________________________________ >> >> _______________________________________________ >> Jsbsim-devel mailing list >> Jsb...@li... >> https://lists.sourceforge.net/lists/listinfo/jsbsim-devel >> _______________________________________________ >> The JSBSim Flight Dynamics Model project >> http://www.JSBSim.org >> _______________________________________________ >> >> |
