Re: [Jsbsim-devel] Fwd: Helicopter

[Simon J. M. <sim...@go...>]

Thomas,

You might already know or be interested in knowing that Titan are using
your bk117 in their sim

"    <author> Thomas Kreitler </author>
    <email> t.kreitler at web 056 de </email>
    <filecreationdate>2010-10-07</filecreationdate>
    <version>$Revision: 1.5 $</version>
    <description> Models a Bell209/AH1S helicopter. </description>
"
regards

Simon

On Wed, 4 Nov 2020 at 22:01, Simon Julie Morley <
sim...@go...> wrote:

> For those that are interested... The flight model patch can be found here
>
> https://github.com/FGMEMBERS-NONGPL/UH-1
>
> On Fri, 30 Oct 2020, 09:39 Simon Julie Morley, <
> sim...@go...> wrote:
>
>> 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
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
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>>>> _______________________________________________
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>>>> _______________________________________________
>>>>
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>>>>
>>>>