DFW-CV

Everything in connection with developing aircraft for FlightGear
bomber
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Re: DFW-CV

Postby bomber » Sat Oct 01, 2016 5:19 pm

No Lester it's not as an afterthought... you kinda don't or won't make a move towards understanding the principles behind JSBsim.

You're starting to sound like Stiglr, where someone must deliver you a flight model that you can just adapt to suit your plane, be it a single engined, mono wing to multi-engined multi wing powered by this that and the other and your plane has hit the numbers or you'll just scream that it's the flight model that's porked...

Complaining the JSBsim is for jet engined planes is rubbish... aerodynamics is aerodynamics the engine just provides thrust... but in the case of a prop plane the prop also supplies some extra wind velocity, that is applied aerodynamically.

You can do your planes in whatever flightmodel system you want...yasim is a blunt instrument. JSBsim is a sharp scalpel that the majority of people are too scared to wield. And so they listen to people like Thorsten and Alant and a few others who tell them how it has to be and accept this.. Rather than standing up against them and challenging it..

I stand up, I don't accept the status quo of doing flight models in a way that is just basically applying a 60 year old mathematical solution and using todays computer processing power to solve it. Because at the end of my appenticeship I saw old hand draughtsmen attempting to use CAD as just another drawing board instead of accepting change. I stand up and it's me that gets the abuse from the old lags, just as I got the same abuse at Targetware. And then there are others that keep their heads down, say nothing, change nothing and everyone likes them, their reputations remain untarnished.

I've asked for people to consider modifying JSBsim to meet the requirements of yasim users....but with all those people keeping their pretty little heads down, not wishing to rock the boat nothing gets changed.

Not for many many years....

At the beginning of this topic I suddenly realised I'd not added prop thrust effect into the beagle pups flight model... so I added it , it took 20mins and I'll never have to do it again for any other plane.

The point I'd like to leave you with is that you can solve a problem using JSBsim which if there was such a thing as a vibrant C++ community could then be added into JSBsim's core code.... that's the future of Outerra.
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

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LesterBoffo
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Re: DFW-CV

Postby LesterBoffo » Sat Oct 01, 2016 6:17 pm

And yet Outerra is not able to run on Windows XP. I've tried it, nope, doesn't even launch. And is it freeware yet in the development realm?

I'm not saying your multi-sectional wing data table approach in JSBsim is wrong Simon, but in the context of practical usage and having new, young and more artistically oriented developers come into the fold of FG, that they have very little choice in making any sort of honest flight model with the two obvious FDM options. Yes, well, there's your approach: but it really takes more than a hobbyists depth of interest in making that work and actually addressing it to a 3D model, let alone having something work and work with any fidelity, at a hobbyists interest level using the other options. I have developed YASim to the best of my understanding of aerodynamics, I feel it's lacking in some factors, but it covers most of the points needed. Not to say that someone may hack in some new features in YAsim the future, I just like that it covers a wide base of ground and air physics at it's present level. And that it's easy to visualize the aero configuration.

And yet, still look at Targetware's FDM, it was pretty brilliant despite being dated. Fully intergrating the FDM and damage model, much like Activision's Screamin' Demons over Europe did. I will hold up these two sims as having been far ahead of the game. Someone did their math and physics correctly on both.


Richard
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Re: DFW-CV

Postby Richard » Sat Oct 01, 2016 6:34 pm

bomber wrote:Complaining the JSBsim is for jet engined planes is rubbish... aerodynamics is aerodynamics the engine just provides thrust... but in the case of a prop plane the prop also supplies some extra wind velocity, that is applied aerodynamically.


JSBSim is a very flexible declarative method of defining a mathematical model for a vehicle. You don't need to use the built in models for thrust, propellers, engines - these can all be defined in a system.

bomber wrote:I stand up, I don't accept the status quo of doing flight models in a way that is just basically applying a 60 year old mathematical solution and using todays computer processing power to solve it.


I think it's fair to say that you've proved that you can use JSBSim in an unconventional way; but what I still don't understand is what's wrong with the standard approach to aerodynamic modelling that everyone uses. It might be old, but then the Newtonian mathematics that we use is even older and that works well.

What I am convinced about is that building aerodynamic models offline using VLM, or flat panel, or CFD - and converting the results into a conventional aerodynamic model does work better than the purely geometrical / airfoil approach of yasim, XPlane, FSX etc.

However I'm still not convinced about the benefits of your approach to modelling - so what I'm now wondering is if it's time for me to build a model to compare against one of yours - and see what comes out of this. I don't know if you're interested in doing this as - but if you are then pick what you think is your best model, give me the geometry and airfoils, propeller RPM and CT/CP and I'll put it through my aero builder and we can see what comes out.

bomber
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Re: DFW-CV

Postby bomber » Sat Oct 01, 2016 7:04 pm

Beagle pup... or cessna 172.
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

bomber
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Re: DFW-CV

Postby bomber » Sat Oct 01, 2016 7:14 pm

Why not get that beagle pup up to top notch in all aspects
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

bomber
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Re: DFW-CV

Postby bomber » Sat Oct 01, 2016 7:52 pm

First off I'm not getting into a how good Targetware was debate with you.... it's the past, the developers decided to pull the plug and leave a lot of us modders high and dry, that was their choice, mine was to carry on with my hobby.

LesterBoffo wrote: I'm not saying your multi-sectional wing data table approach in JSBsim is wrong Simon, but in the context of practical usage and having new, young and more artistically oriented developers come into the fold of FG, that they have very little choice in making any sort of honest flight model with the two obvious FDM options. Yes, well, there's your approach: but it really takes more than a hobbyists depth of interest in making that work and actually addressing it to a 3D model, let alone having something work and work with any fidelity, at a hobbyists interest level using the other options.


Do I understand from what you've written above that you think my approach is too hard for you ?

That you need a more simpler data input approach to getting a complex flight model output than mine and it's why you chose yasim ?

cause if that's the case then we have a very different approach to our hobby... as it's seems you think you should do ALL the plane... frankly I don't want a novice 3d modeller touching a flight model, stick to what you know best, 3d modelling and leave the flight modelling to flight modellers
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

KL-666
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Re: DFW-CV

Postby KL-666 » Sun Oct 02, 2016 10:35 am

D-ECHO wrote:I once added a pushback-like feature to gliders to tow them around, maybe this can be done for these planes too?


I think such thing is not a bad idea at all, to simulate men dragging the plane to the start position by the tail.

I have tested the Camel, which could steer somewhat, but failed to turn my back into 10 kt wind. So i could not taxi to the start of the runway.

Kind regards, Vincent

bomber
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Re: DFW-CV

Postby bomber » Sun Oct 02, 2016 10:48 am

I've another question to Lester and the 3der's here...

How many hours do you put into an exterior model, and how many into an interior ?

On average... humour me considering I 3d model for a living not as a hobbyist.
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

bomber
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Re: DFW-CV

Postby bomber » Wed Oct 05, 2016 10:31 am

Richard wrote:However I'm still not convinced about the benefits of your approach to modelling - so what I'm now wondering is if it's time for me to build a model to compare against one of yours - and see what comes out of this. I don't know if you're interested in doing this as - but if you are then pick what you think is your best model, give me the geometry and airfoils, propeller RPM and CT/CP and I'll put it through my aero builder and we can see what comes out.


I suggest you use the same engine and prop that I use, that way we can be sure that the thrust isn't an issue.

If you provide me with an email addy I'll send you the airfoil and geometry for the beagle...

Simon
"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

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LesterBoffo
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Re: DFW-CV

Postby LesterBoffo » Thu Oct 06, 2016 3:14 pm

Hey Simon, why don't you move this to another thread?

And as far as hours spent making 3D models, what part of doing this as a hobby do you not understand?

When you release something of yours that you put hundreds of hours in as GPLv2, maybe we'll have something to talk about, otherwise..


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