Douglas X-3 Stiletto FSX Native

[Milton Shupe]

Awesome job! I've been excited about this project for a while. I had a chance to fly the X-3 this afternoon after work and it was great...just what I expected. I loved the downard escape system modeled into the aircraft. Having read Mike Millers X-Planes and Scott Libis's Skystreak, Skyrocket & Stiletto - Douglas High-Speed X-Planes, I was expecting the aircraft to be underpowered and susceptible to inertia coupling.

I have FSX Acceleration and did not experience any problems loading or flying the aircraft.

I've only conducted two flights and both were successful. Its easier to land than Captain Sims F-104 (also with thin stub wings and roll coupling issues), once you've deployed both leading and trailing edge flaps. I used the speed break to control the steep descent angles and retracted it with plenty of energy to make the touchdown zone markers. Maintaining the runway center-line was a challenge due to visibility. Accelerated stalls were evident, especially while banking the aircraft or during excessive maneuvering.

Its definitely a challenging aircraft to fly! I can't wait to try the future updates to the aircraft. My future flights will try to address the coupling phenomena that the X-3 experienced and attempt the Mach 1.05 that Joe Walker flew in a dive.

Are there any plans to incorporate a ribbon-drogue chute or the performance of the original X-3 engine (J46) in future updates for a what-if design?

Thank you for that report. Refreshing to hear some positives.

The modeled downward egress system is basic; there are lots of functional parts to the real thing but all eye candy for our purposes.
I had considered the drogue chute but the custom xml coding is not my forte.
Pam had talked about doing a J46 performance flight model from the beginning. That will be her call.

You are correct re; approach visibility, and that was an issue in the RW as well as mentioned in various publications.
Keeping approach speed up (225-245kias) with full flaps will help. Cross fence at 200-215; land at 190~.

 

[Flyboy208]

Flies just fine for me Milton in FSX SP2 ... definitely will have a learning curve and have to watch that wing loading. Managed not to crash it on the first flight , so happy about that. Mike

 

[Milton Shupe]

Flies just fine for me Milton in FSX SP2 ... definitely will have a learning curve and have to watch that wing loading. Managed not to crash it on the first flight , so happy about that. Mike

Thank you Mike. I still crash it if I am not really engaged, just fooling around. Requires concentration and a steady hand in following the procedure all the way down.

There are still a couple of handling things being worked on, one to do with full flaps. Both nose down pitch and drag need to be decreased a bit to allow for a proper short final attitude and speed decay with appropriate thrust, IMO.

 

[Josh Patterson]

Got it out of and back into 18/36 at KOSH (barely). It really does need a braking chute. (I did up the braking force to .95 to cheat a bit and simulate a chute.) Flies nice and smooth and looks great! I've been seeing people have been having crashes. I don't know if I have xmltools or not, (I'm thinking I do as I can hear the AB pop when it engages) but mine is working fine in FSX gold. Thanks for another great X-plane Milton!

 

[Milton Shupe]

Got it out of and back into 18/36 at KOSH (barely). It really does need a braking chute. (I did up the braking force to .95 to cheat a bit and simulate a chute.) Flies nice and smooth and looks great! I've been seeing people have been having crashes. I don't know if I have xmltools or not, (I'm thinking I do as I can hear the AB pop when it engages) but mine is working fine in FSX gold. Thanks for another great X-plane Milton!

Thanks Josh; good report. If you hear the AB POP, it's working for you.

I have been testing at KDFW. It's 7200'+ runways have been sufficient for me.
Are you using the speed brake? Can be deployed at any speed. It helps.

 

[IFlySWA]

What a ride!

Brian

 

[Milton Shupe]

Thanks to Jan Visser "Javis" for the complete, era-correct pilot figure.

 

[delta_lima]

Big thanks to Milton, Pam et al.

I love this (and the XF-92) project. This is so up my alley, it's insane. Thanks so much.

I only had a few minutes and did two circuits of KEDW. I really liked how I was accurately able to dislike the cross-coupling and other behaviours that were characteristic of this plane. I found gentle turns easier than I expected, and most of the handling manageable given a very atypical configuration for such a plane in the early mid-50s.

I found a strange anomaly on finals, where, out of an abundance of caution (aka poor planning), I entered it a bit high, but more or less on speed. Not wanting to lower power too much and risk loosing altitude too quickly with insufficient time to get the engine back up to speed, I deployed air brake briefly, in conjunction with a bit of down elevator.

What happened next was strange - the plane "translated" horizontally in a sharp nose-down attitude, without actually diving, until I retracted the brake, brought the plane back into proper trim, and just used throttle to reestablish my descent rate. With a touchdown, as a result, halfway down RWY22 (facepalm)....

Not sure if it was poor flying on my part, but it was just odd to experience a nose-down translation movement - was wondering if anyone else experienced that. I'd have expected the moment those highly loaded wings saw more airflow in a pitch down attitude, the plane would happily dive.

I get that it's beta, and I will happily watch the progress unfold.

cheers,

dl

PS - best wishes to Pam (huge contributor, I gather) for a speedy recovery!

 

[Milton Shupe]

Big thanks to Milton, Pam et al.

I love this (and the XF-92) project. This is so up my alley, it's insane. Thanks so much.

I only had a few minutes and did two circuits of KEDW. I really liked how I was accurately able to dislike the cross-coupling and other behaviours that were characteristic of this plane. I found gentle turns easier than I expected, and most of the handling manageable given a very atypical configuration for such a plane in the early mid-50s.

I found a strange anomaly on finals, where, out of an abundance of caution (aka poor planning), I entered it a bit high, but more or less on speed. Not wanting to lower power too much and risk loosing altitude too quickly with insufficient time to get the engine back up to speed, I deployed air brake briefly, in conjunction with a bit of down elevator.

What happened next was strange - the plane "translated" horizontally in a sharp nose-down attitude, without actually diving, until I retracted the brake, brought the plane back into proper trim, and just used throttle to reestablish my descent rate. With a touchdown, as a result, halfway down RWY22 (facepalm)....

Not sure if it was poor flying on my part, but it was just odd to experience a nose-down translation movement - was wondering if anyone else experienced that. I'd have expected the moment those highly loaded wings saw more airflow in a pitch down attitude, the plane would happily dive.

I get that it's beta, and I will happily watch the progress unfold.

cheers,

dl

PS - best wishes to Pam (huge contributor, I gather) for a speedy recovery!

Thanks for that report dl.

Yes, I have had that happen because I usually use the air brake and keep power on and speed up. I think my way (faster speed on approach) is not the best because of the actions you stated. We did try to keep use of the air brake neutral in lift and pitch.

It seems if you overfly flaps 4, you will get a strong nose down pitch as described with added lift. The adjustments we intend to make on the flaps are for less lift and less pitch moment on flaps 4. The downside is runway visibility. But, if you can get the final approach speed right, you can use it to you advantage.

EDIT: Forgot to mention that part of the conundrum in managing low fuel approaches is that the CoG is forward of the wing ( -4.3% MAC with gear down, 1-5% MAC Gear up) so the balance is interesting. At near Mach1, the CoG is moving rearward to around the 75% MAC or to the aileron hinge line.

 

[Dev One]

A bit more playing has shown that if one is very gentle using the stick in roll, then she will respond OK & is fairly easy to fly.

I did manage to get beyond M=1 in a dive & subsequently levelled out, where she maintained M=1+ even in a shallow climb, where she stiffened up a bit & was more in her element.

I did though have a problem when passing through turbulence at cruise speed where she was thrown around a lot more that I would expect from a short span high wing loaded vehicle, & recovery was difficult, sometimes almost impossible.

I get the impression that I am not seeing the afterburner effects listed in the aircraft.cfg, only the smoke, also not hearing the subdued bang of the AB lighting up, although the M=1 bang & shock wave visual effect is seen, so not sure if AB clicks in. I do get the various noises of buffet , & U/C down & flaps. Is AB triggered by throttle lever % or indicated RPM %? I get throttle lever position of 37% = 77.9% indicated.

I have reduced the induced drag to 0.8 which helps the climb out & approach, & will try reducing the aileron authority, but can only do this in the flight tuning section because I believe the air file data has somehow been hidden, so not sure how FSX is able to read the data - or is the .air file corrupt?

If one bounces it on landing it leaps into the air nose down, but I think part of that is due to FSX reading that it has exceeded G level & has reset the trim.

I have conducted rolls & a loop or two, although one can too easily stall at the top of the loop, but playing with the flaps as one goes over, one can keep control - just!

I have commented out [Window08], but am not aware the XML tools is loading.

She is challenging but not impossible to fly, I just admire the RW pilots who had no simulation to practice on! Certainly a change from my normal aircraft that rarely get above 200 mph!

One last comment at the moment - being lazy I CTRL+E for engine start - it won't get beyond 24.96% rpm so wont fire up, & the sound file changes & repeats accordingly, one has to hit the start switch. Air file problem?

Hope Pams procedure went well for her.

Keith

P.S. Found I can open the air file in AAM, also found error - it says its a taildragger - cannot change it to see if it makes any difference - also no entry for aileron effectiveness vs Q. Will continue to experiment tomorrow.

 

[Milton Shupe]

A bit more playing has shown that if one is very gentle using the stick in roll, then she will respond OK & is fairly easy to fly.

I did manage to get beyond M=1 in a dive & subsequently levelled out, where she maintained M=1+ even in a shallow climb, where she stiffened up a bit & was more in her element.

I did though have a problem when passing through turbulence at cruise speed where she was thrown around a lot more that I would expect from a short span high wing loaded vehicle, & recovery was difficult, sometimes almost impossible.

I get the impression that I am not seeing the afterburner effects listed in the aircraft.cfg, only the smoke, also not hearing the subdued bang of the AB lighting up, although the M=1 bang & shock wave visual effect is seen, so not sure if AB clicks in. I do get the various noises of buffet , & U/C down & flaps. Is AB triggered by throttle lever % or indicated RPM %? I get throttle lever position of 37% = 77.9% indicated.

I have reduced the induced drag to 0.8 which helps the climb out & approach, & will try reducing the aileron authority, but can only do this in the flight tuning section because I believe the air file data has somehow been hidden, so not sure how FSX is able to read the data - or is the .air file corrupt?

If one bounces it on landing it leaps into the air nose down, but I think part of that is due to FSX reading that it has exceeded G level & has reset the trim.

I have conducted rolls & a loop or two, although one can too easily stall at the top of the loop, but playing with the flaps as one goes over, one can keep control - just!

I have commented out [Window08], but am not aware the XML tools is loading.

She is challenging but not impossible to fly, I just admire the RW pilots who had no simulation to practice on! Certainly a change from my normal aircraft that rarely get above 200 mph!

One last comment at the moment - being lazy I CTRL+E for engine start - it won't get beyond 24.96% rpm so wont fire up, & the sound file changes & repeats accordingly, one has to hit the start switch. Air file problem?

Hope Pams procedure went well for her.

Keith

Good fun!

Yes, when you lose it around M1, it will take a bit to regain control, by design, and per the flight tests.

I have posted 3 screenshot examples you should see as the 3-stage afterburner effects are initiated at (A:TURB ENG CORRECTED N1:2, Percent) 82 &gt ... ). These do not require XMLTools to be installed.
Sometimes you will also see a blue ring depending on speed, altitude, etc.
If you have installed XMLTools, you will hear AB sounds, and a bang when activated/de-activated, among other features.

The air file is present and intact. AirEd will not see details but AAM will.
Why are you trying to modify the handling? This is a beta test; we are looking for detailed feedback from tests, not suggestions for flight model mods. ??? LOL Sorry that Pam and Paul cannot be here to answer your flight model questions.

Not sure how you bounce on landing; do you have Detect Crashes and Damage turned off? Never had a bounce; I either land it or bury it.
Touchdown should be at 180-190kias full flaps.

The START procedure is so simple and documented by a graphic in the Docs folder, and checklist. Seven (7) clicks and you are ready ...

Using cntrl+e does not turn on the following:
1) Master engine switches
2) Boost pumps
3) Avionics Master switch
4) Inverter switch for right side gauges

 

[MrZippy]

I also notice no AB pop or AB power boost or visual effect. I do hit the I key for engine flame. Running FSX with SP2. Window08 is intact.

 

[Milton Shupe]

I also notice no AB pop or AB power boost or visual effect. I do hit the I key for engine flame. Running FSX with SP2. Window08 is intact.

There is no I key effect in this package.
The AB effect is a combination of modeling with attached effects, and custom xml programming controlling when each of the effects shows, and when AB sounds are heard, and at what level.

I believe the FSX Sim AB support code was added with FSX Acceleration... will check.
EDIT: Nope, apparently was available earlier but not sure if SP1 or SP2.

They kick in at 82% N1 approximately.

When I first programmed the AB effects with my preliminary flight model, the AB kicking in would snap your head back with the surge forward. Pam and Paul attenuated that with a more appropriate thrust.

 

[MrZippy]

There is no I key effect in this package.

I get the below effects with the i key.

[SMOKESYSTEM]

//Engine 1
smoke.0 = -24.200, -1.672, 0.520, xf92a_engine_smoke
smoke.1 = -10.045, -1.672, -0.243, xf92a_engine //engine 1 glow
smoke.2 = -10.045, -1.672 -0.243, xf92a_AB //AB 1
smoke.3 = -48.000, -1.672, -5.00, fx_jetblastto2_xf92a , // Take off n2> 74%
smoke.4= -29.774, -1.672, 4.00, fx_heat_shimmer_xf92a , // idle and speed less than 25kias
smoke.5= 0.000, 0.000, 0.00, fx_vapor_x3, // possible use

//Engine 2
smoke.6 = -24.200, 1.672, 0.520, xf92a_engine_smoke
smoke.7 = -10.045, 1.672, -0.243, xf92a_engine //engine 2 glow
smoke.8 = -10.045, 1.672 -0.243, xf92a_AB //AB 2
smoke.9 = -48.000, 1.672, -5.00, fx_jetblastto2_xf92a , // Take off n2> 74%
smoke.10= -29.774, 1.672, 4.00, fx_heat_shimmer_xf92a , // idle and speed less than 25kias

 

[Milton Shupe]

LOL Oh yeah! I do remember them now. Forgive me; I'm older than you are.

EDIT: Let me re-state it - None of the effects are intended to used with the I key.
They are all controlled by custom xml.

 

[delta558]

I'll drop in a couple of responses on the handling, as I know Pam would already have replied to each and every one of your comments!

Firstly, this really is her baby. I only contributed a little with suggestions and help but knowing what it meant to her I was happy to be able to do so.

Thrust - as has been mentioned earlier, it really was underpowered. Gutless, in fact. So much so that my early engine work had the thrust running backwards at a rate of knots, almost as if it was scared to go anywhere. Anyways, it's reasonably accurate now across the range of speed v altitude, from what I remember of the notes and manuals it should be strictly subsonic in level flight and required quite a steep dive (25 or 30 degrees?) to reach max speed.

Flight Handling - reaction to weather, well apparently they would only fly it on a calm day. Also, the coefficients of motion and moments of inertia were set up using realistic levels (F104 figures from Roskam's paper "Airplanes FD and auto flight controls pt1" as a basis, then worked out to the particular aircraft and adjusted to the sim from what I remember). That instantly brings in the unrealistic effects of FS weather, so you may wish to dial that back to around 15% on wind and turbulence effect. Or do what they did in real life and fly only clear skies. There are some major flaws with the handling of the real aircraft (at least one serious departure from controlled flight as a result of a pull-out from a dive) and I know Pam worked hard to get the feel right and incorporate the aircraft's 'bite'. It is not intended as something to jump in and fly around looking at scenery - hopefully there is some effort required to get it to fly right, and the reward is in successfully getting through a flight and pushing the limits. Again, what they did in real life.

Aeros - Jeez, somebody's pulling loops? Okay, so it's not just me If you're going to do it, don't expect advice, sympathy or anything else, just enjoy it.

Take-off - definite need for flaps on this, I think I've seen one FS video where they were not used and rotation speed was closing on 300kts. Basically, any flight under 400kts should have at least 1 stage of leading edge slats and more slat / flap as speed decreases.

Approach - the one thing I really don't like is the pitching from full flaps. It's the lift side of the flaps that is causing this, but the correct amount of lift is being applied and you will see the stalling speed is correct for full flap. Other than that, keep your speed up because it will drop like a stone.

Landing - should be very little ground effect, the gear should cushion the landing reasonably well but there's going to be a long roll out. This is where reality takes a side-step: I believe nosewheel steering was left in 'for comfort'. I initially set it up without, and the rudder loses effect around 90kts. That's a long way to roll if you haven't got the nose pointing in the right direction by that point!

I'm sorry I can't be more detailed in my response, but hopefully it will give you a better idea of some of the things we discussed during the initial preparations for the flight model. There's probably a ton of stuff I've missed out and anything Milton has said is way more up-to-date than I am! Fingers crossed, Pam will be on here to correct me and give you more detail soon.
Cheers,
Paul.

 

[Milton Shupe]

Thanks Paul for chiming in. We appreciate all your efforts.

 

[Josh Patterson]

Thanks Josh; good report. If you hear the AB POP, it's working for you.

I have been testing at KDFW. It's 7200'+ runways have been sufficient for me.
Are you using the speed brake? Can be deployed at any speed. It helps.

I use it entering the pattern to get to gear extension speed then pull it back in. After that I just keep adding flaps and adjusting trim on final until I get set up for a stabilized approach. I've been making my downwind just west of highway 41 then do a 180 just north of Fond du Lac (not really using a base leg) at 250 then bleed off till I'm 200 over the fence and 190 over the numbers. I pop it again after touchdown. It behaves pretty much like SSW's 104 on the approach. (Except it's harder to see out of!)

 

[Josh Patterson]

I'll drop in a couple of responses on the handling, as I know Pam would already have replied to each and every one of your comments!

Firstly, this really is her baby. I only contributed a little with suggestions and help but knowing what it meant to her I was happy to be able to do so.

Thrust - as has been mentioned earlier, it really was underpowered. Gutless, in fact. So much so that my early engine work had the thrust running backwards at a rate of knots, almost as if it was scared to go anywhere. Anyways, it's reasonably accurate now across the range of speed v altitude, from what I remember of the notes and manuals it should be strictly subsonic in level flight and required quite a steep dive (25 or 30 degrees?) to reach max speed.

Flight Handling - reaction to weather, well apparently they would only fly it on a calm day. Also, the coefficients of motion and moments of inertia were set up using realistic levels (F104 figures from Roskam's paper "Airplanes FD and auto flight controls pt1" as a basis, then worked out to the particular aircraft and adjusted to the sim from what I remember). That instantly brings in the unrealistic effects of FS weather, so you may wish to dial that back to around 15% on wind and turbulence effect. Or do what they did in real life and fly only clear skies. There are some major flaws with the handling of the real aircraft (at least one serious departure from controlled flight as a result of a pull-out from a dive) and I know Pam worked hard to get the feel right and incorporate the aircraft's 'bite'. It is not intended as something to jump in and fly around looking at scenery - hopefully there is some effort required to get it to fly right, and the reward is in successfully getting through a flight and pushing the limits. Again, what they did in real life.

Aeros - Jeez, somebody's pulling loops? Okay, so it's not just me If you're going to do it, don't expect advice, sympathy or anything else, just enjoy it.

Take-off - definite need for flaps on this, I think I've seen one FS video where they were not used and rotation speed was closing on 300kts. Basically, any flight under 400kts should have at least 1 stage of leading edge slats and more slat / flap as speed decreases.

Approach - the one thing I really don't like is the pitching from full flaps. It's the lift side of the flaps that is causing this, but the correct amount of lift is being applied and you will see the stalling speed is correct for full flap. Other than that, keep your speed up because it will drop like a stone.

Landing - should be very little ground effect, the gear should cushion the landing reasonably well but there's going to be a long roll out. This is where reality takes a side-step: I believe nosewheel steering was left in 'for comfort'. I initially set it up without, and the rudder loses effect around 90kts. That's a long way to roll if you haven't got the nose pointing in the right direction by that point!

I'm sorry I can't be more detailed in my response, but hopefully it will give you a better idea of some of the things we discussed during the initial preparations for the flight model. There's probably a ton of stuff I've missed out and anything Milton has said is way more up-to-date than I am! Fingers crossed, Pam will be on here to correct me and give you more detail soon.
Cheers,
Paul.

Well, I didn't try any loops, but it does aileron rolls and four point rolls rather nicely!

 

[Milton Shupe]

I also notice no AB pop or AB power boost or visual effect. I do hit the I key for engine flame. Running FSX with SP2. Window08 is intact.

As I said earlier, Delete Window08 from the panel.cfg. It was left in by accident.

Can you verify by tooltip values your Throttle lever percent is >82 or that your Thrust gauges are over 82% when at full throttle.
N1 must be above 82% for AB to kick in.

Also, did you install XMLTools 2.0 for your sim?