Just Retired, and Joined Up.

Hello to everyone here. A bit of background on myself first.

I just took early retirement from working as an Engineering Manager in a tough manufacturing business for 30 years. I had had enough.

I earned a bachelors degree in Aerospace Engineering back in 1985 from University of Kansas under the design professorship of Dr. Jan Roskam (whose name I still see in many places related to flight control and aircraft design). He instilled in me a passion for aircraft design, and I still have my aircraft design that allowed me to pass and graduate from that school.

I ended up working in an industry, that had nothing to do with aircraft, but paid well enough I could retire a few years earlier than most folks I guess. In the back of my mind, still from 30 years ago, that design I made. How would it fly, and look in 3D simulated model?

So, in the years since, I have usually had the MS Flight Simulator, first for Commodore Amiga, then every version since then, and now have FSX. In the last 6 years or so, I had not the time to "play" around with my sim hobby. I had entertained the idea of trying to bring my design from 1985 to flight simulator modeling, but always found other things took priority.

So, now into my retirement 5 months, I dug out all my old class work from the design course. Got the FSX up and running, and did some research. I will be ordering FSDS soon, and have already downloaded evaluation copy of AirWrench. I still have all my textbooks from my university days.

I still have all the design equations for my aircraft, which has the calculations for lift and drag coefficients, drag polars, stability derivatives, 3-view (on paper), all dimensions, weight and balance, etc. Pretty much everything I think I would need to translate the paper design into something that could be modeled into a computer simulation model.

This is something I will be devoting at least some of my newly found free time to in the coming months. I have much to learn and re-learn I realize, and figure that this will be a very long term project.

But, it is something I have dreamed about for decades now.

I will be spending quite a bit of time lurking around, reading, and absorbing things here. Hopefully, others who have built new aircraft designs from the ground up, will be tolerant of my possible future questions.

Oh, by the way, the aircraft I designed is a 60 passenger, short-haul commercial twin-engine pusher turbo-prop. It is a three-surface design with supercritical airfoils. It utilizes un-ducted fans (prop-fans). Somewhat similar to the Piaggio P-180 in planform (already have that aircraft in my simulation model stable), but much larger.

Thanks for your understanding.

It will be interesting to follow your journey. I am not an aircraft model builder, bit X-Plane is reportedly very good for aircraft design and modeling. Might be worth a look. The demo version should show you its capabilities and wether it would be a help to you.

Sent from my tablet thingy!

As an ex-aircraft Design Draughtsman I use Gmax that comes in the disc package for FS2004. I had previously used AutoCAD, so the transition was logical & I can effectively use dimensions then to create the profiles rather than pushing & pulling a shape to fit.

Understanding the FSX or FS9 Flight Dynamics listing might be a bit of a challenge at first, & my experience of using Jerrys FDWB (the freeware version of Airwrench) is good, but one does need to insert changes manually I find as the auto update function can at times mess the whole thing up! Engine power & thrust is a black art!

Good luck, there are plenty of people here & elsewhere willing to give advice gained from their experience.

Keith

Hi EAS100, and welcome. Unlike 'TheYorks' and 'Keefpee' I can't offer any advice at all, but I'll certainly be looking for any updates on your experiences in modelling your design. It sounds like a technically interesting machine; I know there have been a few built designs with similarities - apart from the Piaggio, I recall the (sadly discontinued) Beech Starship, albeit of different size and purpose - and a conceptually comparable RPT aircraft would be definitely one to try. So please tell us how you travel with your project; perhaps you could even manage both FS and X-Plane versions!

Best wishes for the project, EAS100.

Ian / Macsimian, near YBCG, Oz.

As theyorks said, as an engineering type interested in experimenting with aerodynamics, X-plane may be more to your liking

This is just one example of how X-plane is being used as an engineering tool

http://www.jefflewis.net/x-plane_engineering.html

Thanks for the welcome and replies.

Yes, I have been examining X-Plane quite a bit here in the last few days. I do have familiarity with MS Flight Simulator in all its evolved forms, and figured to stick with what I knew. Right now, basically doing a lot of research and homework. My design could stand to do with some updating and revision.

I am finding there is a wealth of tools available now, many free (digital datcom for instance) that were just not available to me back in the mid-1980's. Airfoil design and evaluation tools are also now available.

When I graduated, there was no internet to speak of, and my extent of PC use was limited to VisiCalc and WordStar programs (imagine that.) I never got up to speed really with CAD, having done most of my drafting with the paper, T-square, angles, etc. So, this will be an opportunity to learn some other new skills as well.

My last several years in professional life, were not so much pure engineering, as they were financial and personnel management at the workplace. Seems like I had a bit of talent in counting beans, and making sure transactions followed a profitable track was my forte. I did however keep up with the latest in 3D CAD, often using AutoVue and Solidworks for analysis of things other folks designed.

Anyway, I found this image of an un-ducted fan engine on a sim plane, and have also found some 3D models of them.

Thanks again, and when I get some sort of result (it will no doubt be months in the future), I'll be sure to share. Thanks again.

EAS100,

Welcome to FSCom forum and Simming. i have a project you might appreciate as it concerns flight dynamics. If you download AirEd (I recommend V1.4.2 and not v1.5.2 (for now)) and print out (using Word so you can do page layout) the AirEd.ini (about 24 pages) and have a look in there. Check back in a week and see what you gleened from that. Did you see anything you 'like'? Or did you just get a headache by just looking (hehe).

Notice the AiED file dates - it's ancient, but still works with FSX Accelleration, in case you wonder. I spent 5 yrs (thru 2012) working on dynamics for the vehicles in FS2k2, FS9, and FSX (Porsche 911, F1, etc). I work on cfg and air files everyday. I NEVER have used (or plan to use) 'AirWreck' (as I call it-not my cup of tea). That's a 'last resort' tool to 'fashion' dynamics for a model by a modeler when he doesn't know dynamics. Happy Simming (and tweaking).

Chuck B

Napamule

..I just took early retirement from working as an Engineering Manager in a tough manufacturing business for 30 years. I had had enough..

Good for you mate, I retired at 60 and it was the best decision I ever made, I'm free at last! Let others keep the world going from now on, we've done our bit..:)

"Retirement is the world's longest coffee break"- Anon

PS- I bought X-Plane 10 last year but didn't like it and am sticking with FSX.

X-Plane has got a flawed flight model in single-engine prop planes which makes them slowly develop a bank as if they've got no natural stability, and according to their forum it's a longstanding issue that they never fixed.

Their jets may or may not be alright, I never stuck with it long enough to find out.

Don't forget to hang in our FSX forum to ask questions and advice, that's how I learnt where babies come from, there's nothing those FSX gods don't know. Also check out this thread about the wondrous things you can do with FSX-

https://www.flightsim.com/vbfs/showthread.php?248567-How-do-you-keep-FSX-interesting

In response to the AirEd suggestion, I found both versions and examined the .air files of a couple of aircraft. 1. Piaggio P-180 (for examination of the 3 surface Lift vs. AoA data). and 2. Bombardier CRJ 700 (this aircraft is very similar in size and planform to my design).

A few things I see at this point are:

-There seems to be no provision to allow a true three-surface configuration, however the Lift vs AOA curves are quite different on the P-180 than most other planes. A tweak to simulate the three-surface dynamic? The canard should stall before the main wing.

-Adding separate anhedral and twist to the canard wing seems to be something not programmable either in FSX air files. This has me looking more closely at the X-Plane method of flight modeling.

-The older version of AirEd 1.4.2 did not open so many parameters in FSX air files as did the newer version 1.5.2. I got a lot of "unknowns" on the 1.4.2 list, that 1.5.2 seemed to open fine.

-The parameters for editing in both AirEd and AirWrench are familiar to me. This is the complex nature of aircraft flight dynamics.

-AirEd did not open the 404 lift/AoA table on the CRJ700, whereas AirWrench did. I do not understand what is going on there, but have just started my examination.

My saved course work on the airplane I designed, constitutes a stack of paper over 3 inches thick. Most of the graphs and equations in it are hand drawn and plotted. I see much time will be required to translate these parameters into a form that can be input in the .air and .cfg files.

My design utilizes a fully flying canard on the front to precisely adjust the trim of the aircraft to give all three surface lift vectors, but the tail horizontal stabilizer utilizes conventional elevator and trim tabs. The whole idea was to absolutely maximize fuel efficiency with the proposed technology from the mid-1980's. Maximum efficiency propulsion, with minimum drag (induced or otherwise).

Another complication, is that I can already see that my design from 1985 is lacking in a few areas. My approach will be to first convert what I have into some form I can manipulate with a modern computer, and not worry quite yet about putting into a simulation format. I need to re-verify that the design is completely sound aerodynamically. I do not wish to put into simulation something that could not fly in the real world. That just would not achieve the true ends I have imagined of this exercise.

---

In response to the retirement bliss...yes, I am loving this freedom more and more with each passing day. I know quite a few folks, who retired and about went off the deep end saying "There is nothing to do!". Well, I find myself busier than I ever was working in industry already. Long time dreams of starting a garden, upgrading and repairing things on my house, indulging in other hobbies and interests, and traveling about seem to have me going longer hours than ever before. But now, it is my own time, and my own decision what I do, and when I do it. I sure as heck do not miss that alarm clock blasting my senses every morning.

I FIGURED you would open both versions of AirEd and that's why I (intentionally) mentioned both (it worked - ha). But at least you got to compare a little bit and got a taste of what AirEd can and can't do. This is where I get off (due to 'unknowns'-ha).

You can change the 404 table by holding down SHIFT key and then using the Numpad direction keys (4,6,8,2). Remember that in FSX you can 'over ride' the air file parameters with the data values entered in the appropriate section(s) in the aircraft.cfg. But don't think you can just play with the (flight_tuning) section and get favorable results (a misconception by tweakers). Also, look in the (airplane_geometry) section of cfg for ideas concerning use (or NOT use) of a canard due to no provisions to adjust. It would be the 'horiz stab' along with it's 'incidence' (am I right?). The incidence there can be pos or neg (effects pitch trim (neg or pos)) when on AP Alt Hold. The faster you go the more neg the pitch trim goes-but you can adjust it there.

I have heard of people 'working themselfs to death', where I have never heard of anyone 'resting themselfs to death'. But do pace yourself. Eat right and get some Vitabin D (sunshine). (Ha, looks who is talking-I get paler everyday.) Time for my nap.

Chuck B

Napamule

(Just kidding-I got a garden too, and grass and leaves and weeds so I too get my excercise. But I only do 'work' every other day-for 3 hrs max-strict RULE!!). You can't be too careful.

Welcome to the forums!

If you are looking to see how well your design flies and handles, X-plane might be the better sim. It is more like a wind tunnel you stick your model into. While it isn't perfect it can give a good idea of how a new design might actually fly. FSX is aimed more at simulating an existing design where performance and handling is already known. Although in the end, both are desktop flight sims with limitations.

My saved course work on the airplane I designed, constitutes a stack of paper over 3 inches thick. Most of the graphs and equations in it are hand drawn and plotted. I see much time will be required to translate these parameters into a form that can be input in the .air and .cfg files.

For the sake of completeness I would like to draw your attention to JBSim. Problem with MS FSX and X-Plane is that they are both "black boxes" (something engineers should be familiar with ;) )

JBSim is an open source flight dynamics model, and it's used - amongst other - by the open source FlightGear simulator. The big problem with FlightGear however is total lack of eye candy.

Still, you might be interested to take a look

http://jsbsim.sourceforge.net/

I have found that FS9 & FSX appear to be approximations to real world aerodynamics, with I suspect a whole load of addon correction parameters that are not needed in a lot of cases. One example I think is the Cl vs Alpha curve, all one really needs is the slope & zero degree intercept to be close, but others note that the Cm vs Alpha (as well as the Cl vs Alpha) are for the complete aircraft, not just the lifting wing. Also bear in mind that the centriod of the aircraft is set at the 25% chord, so more corrections need to be added to avoid excessive trim change with speed!

Its also worth a look & to download Herve Sors programs http://www.aero.sors.fr

Keep at it, you could surprise all of us. It can get very addictive....

Good luck

Keith

P.S. Once starting the 3d process either by Gmax or possibly FSDS, keep saving almost every stage that you draw as a separate file issue. Gmax will & can bite leaving you with a saved unreadable file sometimes, requiring a repeat draw of the newer bits....welcome to Frustration Street.

There are these 3 weird and wonderful Aircraft Realism sliders in FSX, P-factor, Torque and Gyro, I usually have them about halfway.

I keep meaning to twiddle them to see what they do, but keep chickening out-

http://i53.photobucket.com/albums/g64/PoorOldSpike/sub2/FSX-aircraft-setts_zpsr2mevukt.jpg~original

It's been several months since I last posted. Retirement has sent me in multiple directions, with multiple activities. Trying to get that bucket list done, while the body is still reasonably operational. Went up to Montana last fall, and camped out at Glacier National Park several days. Got a HAM radio license. Rebuilt two decks. Grew a nice garden, and built an automatic drip irrigation system for it. Lots of painting indoors. Lots of plumbing work. Getting with doctors and dentists on various issues. On and on. But...

With the cold weather, I've spent a lot of time indoors at the computer.

Thanks for the suggestions on JSBSim, and the Sors files. My collection of programs, files, and other items grows. Finally had my old blueprint shop scan my old vellum 24" x 36" 3-view into high resolution TIFF, and proceeded to clean it up (lots of pixels needed to be blanked out from the scan). I've finally started on working with FSDS and Gmax both, trying to learn that methodology. My brain is not what is was in my mid-20's by any stretch.

Working on a number of fronts. I want to recalculate the entire aircraft system using the classical methods I learned years ago, but using modern computer analysis. Digital Datcom has me quite interested right now, as does virtual wind tunnel analysis. Been rethinking my airfoils, and high lift system. Winglets were not on the original design, but will no doubt be added.

In short, still here, but moving in deliberate calculated steps. So much to learn, but it is all good. I'll return when I have something a bit more fleshed out.

Good for you mate, I retired at age 60 seven years ago and have never been happier because retirement is one long coffee break..:)

You mention HAM radio, gardening, irrigation, painting, plumbing, so I'd recommend this good discussion forum which has categories for stuff like that, I'm a member there myself under the screenname 'Gamer'..:)-

http://thesurvivalpodcast.com/forum/

Hi & Welcome to the forums. I noticed that you list that you live in TN. In case you have interest there is a flight simulator "gathering" this coming June 11-12 called "Flight Sim Con 2016". Here is the link http://www.flightsimcon.com/

The reason I mention this is that Austin Meyer, the founder of X-Plane, is a speaker this year. He was also a speaker at last year's event. This is the 4th year of Flight Sim con. The event is held at the New England Air Museum at Bradley Airport in Windsor Locks, CT. I attended the last 2 years, and going again this year. It is a great place to meet up with friendly FS folks, and attend various seminars. I am not aware of any similar event in the US.

Thanks for the info on the simulator convention. I am more of an "out west" fellow though.

I have put a couple images of my design(so far) on the Aircraft Design sub-forum. This gives a good visual sense to what I have written so far in previous posts. Several thousands more details to work on, but now I can see in 3D space, what used to be only on hand drawn vellum.