Convair Delta Wing Test

[Sundog]

Very interesting Sundog. But I have a question. When I got to fly the C-17 simulator, the instructor made a "big deal" out of the fact that the C-17 lands "on the back side", meaning on the back side of the power curve, a high AOA (low speed) region where forward and aft stick movement affects speed (AOA) and power controls glide slope (altitude). It's the same place on the power curve where navy jets approach the carrier, which is why they fly approaches the same way. Since all these delta-wing jets land at high AOA, might they "simply" be operating "behind" the power curve on approach, like C-17s and F/A-18s? I do wish FSX (etc.) modeled this interesting behavior better!

As Rick said, the backside of the power curve is normal for all aircraft. It''s basically a plot of drag and available power. It's usually noticeable on landing because you're in a high drag low power configuration. If you remember that old video of the F-100 where the pilot comes in too slow and he tries to correct by pulling the nose up and only gets slower then finally stalls and rolls into the ground. Basically it's where the drag generated is higher than the power available. Modern aircraft usually have enough excess power that they can add smash and fly out of it. The F-100 didn't have that much power available at low speeds. The pilot got slow and tried to compensate with more alpha, which lead to even more drag, and he really didn't have any way out since they didn't have zero-zero ejection seats in those days.

Here's a graph of it. Power available is what your powerplant produces and power required is the total drag curve. When you get to the left side where the power required (drag) is higher than the power available, that's the backside of the power curve. Most aircraft will stall before they get into this region of the envelope.

What I'm talking about with regard to the delta is basically how the flight controls which control pitch also effect the camber of the wing. With a tailed aircraft, you push the stick forward, the tail lowers the nose (alpha), the wing is at lower alpha and if density and speed (dynamic pressure) remain constant, you generate less lift. With a delta, you push forward on the stick, which will push the nose down, and lower alpha, which lowers lift, but it will also increase lift because you've just increased the camber of the airfoil. The exact opposite happens for pitching up.

At small increments of alpha, the higher dynamic pressure means you don't have to deflect the flight controls much, so the camber change is most likely negligible, but based on what I've read of most deltas, it's really noticeable at low speeds and high alpha, such as on approach to landing.

[Mach3DS]

That poor soul in the F100 video had more than just low power to contend with. They couldn't control roll coupling in Swept wing aircraft very well at that time and I think he suffered from that as well. Inexperience with heavy slow Jets can equal disaster at times.

[Milton Shupe]

Interesting topic and discussion guys. Just curious who has the knowledge and skills to do the flight model :-)

Update: invested the last three days getting the nose and main gear started and doors and bays cut in.
Now that the basics are done, I can clone to the right side, add details and animate.
I'll be another day on main gear and associated fuse and wing parts.

[Sundog]

Interesting topic and discussion guys. Just curious who has the knowledge and skills to do the flight model :-)

I never looked at how they did the Concorde FM, but I'm betting if anyone has experience with how to implement a good delta FM, it's Glowing Heat (maybe he'll offer some advice). I've made some FM's before and for jets, I find the most difficult part is finding a good engine deck to reference. I only have a couple of them. I don't recall the FDE having a delta option and I've been thinking about how you make it work. Do you make the wing and elevator "overlap" and artificially reduce the parasite drag based on the actual surface area as opposed to the doubled control surface area the sim would see? Do you also model them as flaps, to effect the wing lift as they are deflected as well?

I'll be more than happy to help out where I can, but between guitar lessons and practice, working around the house (too many projects), and writing a book with a lot of graphic art I have to complete, my calendar is full. Also, once a month I have to make the news letter for the model hobby club I'm in (Will-Cook IPMS). I mean, it's so bad, the only thing I assemble in the hobby club right now is the news letter. Here I thought I would finish my 1/72 Sukhoi PAK-FA/T-50/Su-57 before the end of the year. That's all after my day job. So I can help, it just won't be quick.

The preview shots look great so far. Of course, I'm never surprised by that from you.

[heywooood]

check out this one - by Rayl @ http://www.virtualaerodrome.com/image_detail.html?p_aircraft_id=633&p_user_id=1042 &p_image_id=33691

[heywooood]

this is a scratchbuilt balsa display model - rayl is an active contributor at the VA website - he may have some interesting plans and photographs to share. I dunno about FM's though...but certainly drawings and pictures etc..

[Milton Shupe]

I never looked at how they did the Concorde FM, but I'm betting if anyone has experience with how to implement a good delta FM, it's Glowing Heat (maybe he'll offer some advice). I've made some FM's before and for jets, I find the most difficult part is finding a good engine deck to reference. I only have a couple of them. I don't recall the FDE having a delta option and I've been thinking about how you make it work. Do you make the wing and elevator "overlap" and artificially reduce the parasite drag based on the actual surface area as opposed to the doubled control surface area the sim would see? Do you also model them as flaps, to effect the wing lift as they are deflected as well?

I'll be more than happy to help out where I can, but between guitar lessons and practice, working around the house (too many projects), and writing a book with a lot of graphic art I have to complete, my calendar is full. Also, once a month I have to make the news letter for the model hobby club I'm in (Will-Cook IPMS). I mean, it's so bad, the only thing I assemble in the hobby club right now is the news letter. Here I thought I would finish my 1/72 Sukhoi PAK-FA/T-50/Su-57 before the end of the year. That's all after my day job. So I can help, it just won't be quick.

The preview shots look great so far. Of course, I'm never surprised by that from you.

Sundog,

I wasn't really asking; just commenting in jest.

The plan right now is I'll do a basic FM for testing.
Then I'll turn it over to Rick to deal with :-)

I am doing this project for Rick and he will take it where he wishes once I am done modeling.

Thanks
Milton

[Sundog]

Sundog,

I wasn't really asking; just commenting in jest.

The plan right now is I'll do a basic FM for testing.
Then I'll turn it over to Rick to deal with :-)

I am doing this project for Rick and he will take it where he wishes once I am done modeling.

Thanks
Milton

:: phew::: That was really going to work on my time management skills!

[Dimus]

Brent Stolle did a fantastic FDE for the MTM Mirage 2000C. Maybe if you intrigue him enough?

[Milton Shupe]

:: phew::: That was really going to work on my time management skills!

LOL Sir; I appreciate that you are always willing to help.

Brent Stolle did a fantastic FDE for the MTM Mirage 2000C. Maybe if you intrigue him enough?

Good point Dimus; he would be good. Bernt usually contacts me when he has an interest. Not sure if Rick has anyone in mind or not but I'll leave it to him to sort out.

[Milton Shupe]

this is a scratchbuilt balsa display model - rayl is an active contributor at the VA website - he may have some interesting plans and photographs to share. I dunno about FM's though...but certainly drawings and pictures etc..

Very well done model; looks great.

I will not be needing drawings or ref pics unless there is something available for the cockpit. Everything is done. Thanks

[Mach3DS]

My plan was to enlist my good friend and coworker who is an aerodynamics engineer for Boeing Defense on the super hornet to help me tune the FDE to something fairly close.....that's the plan anyway! Milton had been humoring my idea requests. So I have some ideas for what I would like to see be in the final released package, but I'm keeping those under wraps right now until I can figure out how to do it or if it can be done. I'm reaching out to my developer friend network (not for the work) to answer my questions of if it can be done and how it could be done.

[Bjoern]

I never looked at how they did the Concorde FM, but I'm betting if anyone has experience with how to implement a good delta FM, it's Glowing Heat (maybe he'll offer some advice). I've made some FM's before and for jets, I find the most difficult part is finding a good engine deck to reference. I only have a couple of them. I don't recall the FDE having a delta option and I've been thinking about how you make it work. Do you make the wing and elevator "overlap" and artificially reduce the parasite drag based on the actual surface area as opposed to the doubled control surface area the sim would see? Do you also model them as flaps, to effect the wing lift as they are deflected as well?

Engine data may be a bit of a problem, but the J33 allows extrapolation from data for other aircraft (T-33, P-80, etc.).

No point in defining a delta planform in the FDE when you need to determine its aerodynamic characteristics by coefficients (C_L, C_d, etc.) in the .air file and aircraft.cfg anyway. Same for elevator influences in terms of pitch acceleration, moment and drag increase.
FSX flight dynamics reference (minus engine-related things): http://fsdeveloper.com/forum/resourc...msfs-v1-0.169/

The worst thing about making FDEs is having to fill gaps (usually a lot and very wide) in source data with a lot of time-consuming trial and error.



Some charts containing aircraft characteristics are displayed in this video:
https://www.youtube.com/watch?v=2HKQ87g4SsQ

[Milton Shupe]

Some wire frames to share here; I know some folks like to see such things.

[Mach3DS]

Thanks for those links Bjoern! The video is a good one I e watched many times since a few years back...

Milton those shots are impressive!

[YoYo]

Nice choice and part of interesting history!!!
P3Dv4 ready also ? (pretty please)

[odourboy]

Great photo Yoyo!

[Milton Shupe]

Nice choice and part of interesting history!!!
P3Dv4 ready also ? (pretty please)

Best photo of my archives now.

P3Dv4 of course. :-)

Thanks

[Milton Shupe]

Just got the first cut of the flight model, and our First flight ...

[warchild]

wht arent there any "like" buttons on this page?? Looking fantastic Milton.. I love it already..

[Milton Shupe]

wht arent there any "like" buttons on this page?? Looking fantastic Milton.. I love it already..

Thank you Pam; I was surprised in went into the sim so easily on a first cut FM. No probs in taxi, takeoff or climbout, great stability, but underpowered at the moment.

I am missing N1 and N2 numbers for the J33-A-29 variant on this first cut but at least we have the basics in place for balance and stability.

Took her to FL250 no problem; handles well.

We are happy with this start.

Now, back to modeling to populate the cockpit with some basics, then onto the mapping for textures.

[Flyboy208]

Such a cool project ! Love the exotic X types. A good family friend was a USAF test pilot who knew Yeager well and had some great stories to tell. Mike

[Mach3DS]

Milton if need be, we could also opt for the J33-A-16, which might have more information available. Which is the final engine variant with Afterburner that NACA had installed for all of Scott Crossfield's flight testing.

[napamule]

Josh,
Paul Clawson made one (FSDSv3, for FS2004) back in 2005. It flys well in FSX. I did not use Rob's VTOL Gauge - made my own FDEs, Turbo-Prop. Here is a video of it landing on Tokyo Skyscraper Helo Pad in FSX Accel. Link: https://www.youtube.com/watch?v=Hr5xjupE3MU . But you have to learn to fly it and most simmers don't have the time or patience to learn how to fly it. Flys like a helicopter so there is a learning curve. But it's 'airplane' not helicopter FDEs.
Chuck B
Napamule
Edit: Found the link to video of it flying in FS2004. Link: https://youtu.be/VP8EdVX6LdU

[gribouil]

Hi Milton and Team,
I can contact Jean-Pierre Bourgeois (BEEGEE as he is known on several FS forum) who worked on the Restauravia Mirage III and did marvels on her FDE if you want?
Cheers,

Stéph.