F-5E simpit cockpit dimensions and flight controls

[Bucic]

I've noticed there's no simpit thread for the venerable Tiger. While I do not intend to build a home cockpit for F-5E I am in the process of building some dirty bootleg flight controls for it with some aspects mirroring the flight controls of the real F-5E, namely the stick travel and forces. I'm willing to share what I'm going to find but after a week of research I have to start like a beggar - has anyone got any cockpit dimensions like those easily available for F/A-18 and several other jets?

1. control stick pitch/roll travel range and neutral point location vs the roll limiter - the DCS implementation of it specifically (see ch. 4.1 of the DCS manual Aileron Spring Stop)

A: As described in document AFFDL-TR-71-134 (AD0738625.pdf) (courtesy of nairb121), see the post

A: The DCS implementation: DCS does NOT alter the input sensitivity between 'limiter enabled' and 'limiter disabled' states i.e. good news ; key command: L - Aileron Limiter (Hold to turn off) (or lower the landing gear, in real F-5 the mechanism is triggered by the front landing gear) ; the real implementation is via additional spring force past the aileron limiter for normal flight (to still make the range available for emergency situations)

Quote

Apart from the artificial feel system there's also an additional force spring in the roll channel to limit roll in normal flight but provide additional authority for the purpose of landing. - DCS manual(?)

1A. stick arm length - from pivot to the middle of the palm or to the grip base

A: (partial) the stick column movement axes are on different heights - the roll axis is above the floor, the pitch axis below the floor. 80 mm assumed for now for each.

2. rudder pedals travel range - for now I assume +/- 55 mm

A: In actuality it's much bigger: +/- (179/2) mm

3. Split throttle mechanism operation

Still unknown...

 

TODO:

[ ] seat height range from modelviewer
[ ] throttle range mapping in DCS to prevent from going into AB

[ ] axes vs encoders
 

 

Model Viewer ModelViewer questions and issues:

0A. Orthographic mode for measurments!

0B. Only full screen screenshots! (alignment)

1. How to MOVE the camera? How to use free camera mode? I need that to confirm my initial guess as for the plit throttle mechanism.

2. How to remove the pilot body model? A: argument 775

3. Is there a list of arguments with descriptions? A: NO, there is no standardized list for aircraft cockpits in DCS 71 and 74 are the control stick but man, it's exhausting to go through them manually.

 

Model Viewer Arguments:

775 hide pilot body

771 seat adjustment vertical

A list of arguments I tested manually for the F-5E cockpit model - attached below.

 

 

REFERENCES FOR DIMENSIONING:

1. The control stick grip B-8 is ~160 mm high.

2. Personally I'll rely mostly on the knees for the control stick positioning. Especially that I do not intend to build a seat mirroring the cockpit arrangement of F-5E. My sitting position will be higher.

 

reference cockpit photos from a museum F-5

http://www.primeportal.net/hangar/bill_spidle_f-5e/f-5e_74-1558_fwd_cockpit/index.php?Page=1

 

 

Throttle - chaff switch - modelviewer argument 115, 116 or 117 (along with flaps LEVER and brake switch)

https://forum.dcs.world/topic/303369-chaffflare-release-button/

 

REAL WORLD REFERENCES

Quote

F -5A vs F-5E vs T-38 : force feel system on the actual aircraft. Springs plus additional forces in function of current G force via weight bob. (...) please note that while F-5A and F-5E are quite similar the control system in the area of the force feel assembly has seen a significant redesign hence resources from the A variant (or T-38 Talon for that matter) may not translate directly to the E variant.

source: me

Throttle details from the RL manual

Quote

THROTTLES
The throttle (figure 1-31) for each engine provides main engine control from OFF to IDLE, IDLE to MIL and afterburner control from minimum to maximum (MAX) afterburner operation. Each throttle controls respective engine fuel supply, fuel shutoff valve, main fuel control throttle angle and stopcock valve, main and afterburner ignition circuitry, engine speed, and afterburner control operation. The left throttle also controls crossbleed start valve circuitry. Fingerlifts on the forward side of each throttle (® front cockpit) provide a stop detent at IDLE. Raising the fingerlift permits retarding the throttle from IDLE to OFF. In the IDLE to MIL range, throttle friction . is constant. A spring detent between MIL and MIN afterburner must be passed over for afterburner or nonafterburner operation. Afterburner thrust modulation is provided throughout the afterburner range. Throttle friction in the afterburner range is slightly greater than that provided from IDLE to MIL position. Throttle friction is preset and not adjustable by the pilot.

throttle sight switch

 

PHOTO WALKAROUNDS

https://forum.dcs.world/topic/263518-real-f-5e-tiger-ii-hotas-screenshots/ -> YT https://youtu.be/dg4zsQ7coJc?t=1071

http://www.primeportal.net/hangar/bill_spidle_f-5e/f-5e_74-1558_fwd_cockpit/index.php?Page=1

 

REFERENCE THREADS

---

started by me:

https://forum.dcs.world/topic/318926-controls-indicator-figuring-out-real-stick-movement-range/

https://forum.dcs.world/topic/318756-controls-indicator-proportions-and-neutral-point-position/

---

 

https://forum.dcs.world/topic/149476-f5e-panel-dimensions/

https://forum.dcs.world/topic/304611-artificial-feel-in-the-f-5-and-other-jets/

 

https://forum.dcs.world/topic/229796-model-viewer-tips-tricks/

scale modeling https://designer.home.xs4all.nl/models/f5-72/f5-tiger-aircraft-man.htm

https://forum.dcs.world/topic/188402-brunner-force-feedback-joystick-base/

https://forum.dcs.world/topic/188402-brunner-force-feedback-joystick-base/page/12/#comment-5124308

 

https://ocw.mit.edu/courses/16-885j-aircraft-systems-engineering-fall-2004/pages/lecture-notes/

https://ocw.mit.edu/courses/16-885j-aircraft-systems-engineering-fall-2004/resources/aero_primer/

https://ocw.mit.edu/courses/16-885j-aircraft-systems-engineering-fall-2004/resources/aircraft_murman/

 

3D printed components

switch caps https://forum.dcs.world/topic/313480-buttonswitch-caps-and-covers/#comment-5147689

DIY throttle fingerlifts https://forums.mudspike.com/t/throttle-finger-lifts/9954

 

Hornet

https://simhq.com/forum/ubbthreads.php/topics/3351156/F_A_18_Hornet_Pit_builders_Hor.html

http://aviationarchives.blogspot.com/2016/12/early-years-in-hornets-nestf-18-growing.html

https://forum.dcs.world/topic/252987-hornet-stick-feeling-in-the-aircraft/page/2/

detailed photos of the full 18 throttle quadrant assembly   https://aerotronicsllc.com/f18throttle.htm

 

F-15 Eagle

F-15C Flight Simulator Project — https://www.f15sim.com/

 

 An "official" package with modelviewer arguments for object types other than cockpits:

On 10/30/2014 at 4:05 PM, SVKSniper said:

Here....;)

arguments.rar 33.29 kB · 296 downloads

 

Courtesy of Viper1970 https://designer.home.xs4all.nl/models/f5-72/f5-tiger-aircraft-man.htm

 

draw arguments for F-5E v01.txt

Edited February 28, 2023 by Bucic

[streakeagle]

There is an old thread that may be of some interest to you: 

 

[Bucic]

@streakeagle

Not much in there, apart from side panels... When I finish the rudder pedals I'll probably get what I need for the stick and throttle using the DCS model viewer.

 

Edited January 26, 2023 by Bucic

[Bucic]

Pfff. Who needs museums when you have the model viewer

 

[Bucic]

The original topic updated. I'll be posting my findings and I'd appreciate if anyone dropped answers to some of the unknowns.

[Bucic]

A list of 3D model draw arguments for the F-5E added.

[agrasyuk]

Measured from the floor. The tape has both metric and normal units on it for your convenience:)

 

 

[Bucic]

On 2/7/2023 at 12:41 AM, agrasyuk said:

Measured from the floor. The tape has both metric and normal units on it for your convenience:)

 

Thank you! How many measurements I've got left?

It seems to me that the distance between the floor and stick pitch (below the floor) and stick roll (above the floor) axes is similar at around 80 mm. So for anyone making a gimbal mechanism with axes at the same level I guess the floor level would be a good approximation.

And thanks to https://forum.dcs.world/profile/73814-nairb121/  we've got some solid data on the control limits and forces! Assuming the data in AFFDL-TR-71-134 (AD0738625.pdf) are applicable to F-5E as well.

The bad news is that my finished rudder pedals won't accommodate that huge +/-3.52" (+/-89.4/179 mm total) movement range. The good news is I wouldn't want this much of travel anyway.

[Bucic]

A juicy update just in for Valentine's Day, TheSimNet has updated his B8 grip model package for 3D printing to include the F-5 variant of the grip (with palm rest)!

Century Series Grip - F-4 Phantom Joystick + Many Aircraft by TheSimNet - Thingiverse - https://www.thingiverse.com/thing:5764003

[agrasyuk]

On 2/8/2023 at 4:53 PM, Bucic said:

Thank you! How many measurements I've got left?

 

 

You have as many as you need. As long as I can clearly explain to the owner from what to what I need the measurement to be taken

[Bucic]

3 hours ago, agrasyuk said:

You have as many as you need. As long as I can clearly explain to the owner from what to what I need the measurement to be taken

Thank you. After I finally got the data on stick travel (see AFFDL-TR-71-134) I need to compile a basic side-view drawing with some basic dimensions and see what we're missing.

[Bucic]

So, I've entered everything known, unknown and assumed into a spreadsheet. It was enough for me to help me figure out the stick positioning. I'm using lumbar back support and my room floor as dimensioning datums. I've glued a V mock-up out of tin strips of wood showing me the forward-aft movement range of the stick. It turns out my stick mechanism is going to reach all the way down to the floor, without any clearance. Now I have to figure out how to actually attach it firmly. Unfortunately I have to use my office chair. On an upside, it has a massive 5-arm metal base and it's scrap. I can drill and tap into it to my hearts content. Another challenge is that the stick has to be easily removable, complete with the gimbal mechanism.

 

EDIT:

The spreadsheet updated.

EDIT 2:
Throttle: This will come in handy for throttle detent mapping!

 

F-5E simpit flight controls movement geometry v202202D.ods

Edited February 25, 2023 by Bucic

[Bucic]

2023-04-30 update
I had some other things to take care of. Some are related to the project. Like the making of legs for my workshop bench/planing board. I got really tired of working on a bench with two wobbly chairs as the base. Refurbishment of a drill stand was another of these jobs...

All 3 sets of controls are mostly finished mechanically and with all the functional replica features I mentioned previously. To be done, main items:
• the weapon and fuel control panels
• some switches made from scratch, e.g. the speed brake switch, flaps lever
• control stick grip - 3D print or wood, haven't decided yet
• throttle grips - sheet metal
• seat mounts for stick and throttle, the base for the rudder pedals is already integrated

 

Edited April 29, 2023 by Bucic

[Bucic]

I'll be looking into re-working of the 3D printable models by TheSimNet. The amount of supports required for this arrangement is massive and with the stick print time at over 10 hours it's going to amount to about 20 hours total when the armature is included. And I'm not even talking about the stick column (tube). Generating tree type supports reduced the printing time by 2 hours but I still think 8 hours coul be cut. I'd like to investigate a horizontal arrangement with 2 halves printed separately.

[_BringTheReign_]

3 hours ago, Bucic said:

I'll be looking into re-working of the 3D printable models by TheSimNet. The amount of supports required for this arrangement is massive and with the stick print time at over 10 hours it's going to amount to about 20 hours total when the armature is included. And I'm not even talking about the stick column (tube). Generating tree type supports reduced the printing time by 2 hours but I still think 8 hours coul be cut. I'd like to investigate a horizontal arrangement with 2 halves printed separately.

Hey there! I don't believe that many supports are necessary - the only mandatory supports are the ones under the handrest. The rest should be fully printable without any supports whatsoever. I do usually put two under the trigger extrusions like so, but they are not strictly necessary for a functional print:
null

[Bucic]

4 hours ago, _BringTheReign_ said:

Hey there! I don't believe that many supports are necessary - the only mandatory supports are the ones under the handrest. The rest should be fully printable without any supports whatsoever. I do usually put two under the trigger extrusions like so, but they are not strictly necessary for a functional print:
null

Thanks for chiming in! And, again, I salute you for your continued contributions! The F-4 grip was a godsend already, and then, bam!, F-5 grip update!

Have you investigated splitting the model in two halves, as you'd do in case of casting?

 

I'm trying to lay out support blockers in Cura. It's rather cumbersome but I'm curious. What times did you manage to cut down the printing process down to?

 

[Bucic]

6h32 minutes and 72 grams of filament is all I could do so far.

[_BringTheReign_]

6 hours ago, Bucic said:

6h32 minutes and 72 grams of filament is all I could do so far.

That's really good time, mine are usually 8-9 hours

7 hours ago, Bucic said:

Have you investigated splitting the model in two halves, as you'd do in case of casting?

Yes, however I have had a lot of issues with the knurling when it prints sideways - it comes out looking like a very frizzy topographical map because the knurls end on an infinite point that the slicer tries to justify into a segmented set of layers. But that might just be my slicer and my printer. Will include halves for both in the next update at the end of the summer!

[Bucic]

On 8/18/2023 at 5:36 AM, _BringTheReign_ said:

That's really good time, mine are usually 8-9 hours

Yes, however I have had a lot of issues with the knurling when it prints sideways - it comes out looking like a very frizzy topographical map because the knurls end on an infinite point that the slicer tries to justify into a segmented set of layers. But that might just be my slicer and my printer. Will include halves for both in the next update at the end of the summer!

Sounds awesome!

The printer I borrowed sure is a handful. Not only it's an off-brand model, it's got more surprises!

I decided to investigate the issue of the blower not working (the one blowing down). Apparently it is the one more important for the printing quality...

Initial state:
1. the fan on the block works, and is correctly controlled by the slicer software/g-code.

2. there is no mention of a second fan in the configs.

I deduce from 1 and 2 that there must be something wrongly connected. The results of the investigation:
(a) the fans were connected in reverse (swapped places)
b) ADDITIONALLY, the connector on the circuit board was connected with the + and - swapped, so the fan connected to that harness simply did not work at all. Now they both work and I am going to print the tunnel for that down-blower tomorrow.

https://lumeplus.wixsite.com/lume/product-page/lume-orange

 

Edited August 20, 2023 by Bucic

[Bucic]

 

I didn't imagine this is going to turn out so fine. If something goes badly later it doesn't matter, I'm going to fix it. I'm talking about the quality of the print. I made sure to watch the creation of that first hanging layer of the palm rest. Man! It looked so satisfying! Like a bogus marketing video

 

Edited August 31, 2023 by Bucic

[Bucic]

On 8/18/2023 at 5:36 AM, _BringTheReign_ said:

 Will include halves for both in the next update at the end of the summer!

@_BringTheReign_ Is that close-to-real extension model https://youtu.be/3D4wnmjt9E0?t=178 intended for sharing as well by any chance? I could really use it right now as it's the time I need to figure out all of the components between the grip and the gimbal.

 

EDIT:

@_BringTheReign_ I'm going to use this section for the TheSimNet grip issues:
https://www.thingiverse.com/thing:5764003

- missing in the BOM: M2 threaded brass insert ?3 pieces?

- BOM: screw head type: flat head (conical) -> slot head (cylindrical)

- YT channel: Discord invite link invalid?

- the TRIM HAT hole (round) not fitting on the ALPS RJK 4-way switch (half-round) shaft

- the F-5E thumb switch hat hole (round) not fitting on the ALPS RJK 4-way switch (half-round) shaft

 

Edited August 31, 2023 by Bucic

[Bucic]

@_BringTheReign_ Laugh all you want, but I'm confused as far as the ALPS switch go. I finally found an affordable source, so I bought 2. 1 for the trim, 1 just in case. I noticed the ALPS switch is really small. So small it almost fits the thumb hole... <cogs turning> ... wait... picked up the thumb connector (the one from the F-5E grip file thesimnet_F5_Grip.stl). Damn! It fits! And since the switch has a press action as well it pretty much solves everything in that area. Now a stupid question: was that your intention? I mean, to use TWO ALPS switches for the F-5E variant of the grip?

Edited August 26, 2023 by Bucic

[_BringTheReign_]

On 8/25/2023 at 7:34 PM, Bucic said:

@_BringTheReign_ Laugh all you want, but I'm confused as far as the ALPS switch go. I finally found an affordable source, so I bought 2. 1 for the trim, 1 just in case. I noticed the ALPS switch is really small. So small it almost fits the thumb hole... <cogs turning> ... wait... picked up the thumb connector (the one from the F-5E grip file thesimnet_F5_Grip.stl). Damn! It fits! And since the switch has a press action as well it pretty much solves everything in that area. Now a stupid question: was that your intention? I mean, to use TWO ALPS switches for the F-5E variant of the grip?

Yes this was indeed the intention! 
I have been running into an issue with the alps switches where the push is activated verey time I rock the switch in a direction - this is apparently a common issue with with using the alps switch in a DIY project, but a gentleman by the name of imarchemides on reddit figured out a custom PCB that solves this issue. I am still tinkering with it, but in the meantime I have been using standard 5-way switches like these ones: Thru-hole 5-way Navigation switch : ID 504 : $1.95 : Adafruit Industries, Unique & fun DIY electronics and kits 
Even cheaper copies are available from ali express, etc. These switches are pretty good, but I will continue trying to make the alps switches work perfectly!

[Bucic]

4 hours ago, _BringTheReign_ said:

Yes this was indeed the intention! 
I have been running into an issue with the alps switches where the push is activated verey time I rock the switch in a direction - this is apparently a common issue with with using the alps switch in a DIY project, but a gentleman by the name of imarchemides on reddit figured out a custom PCB that solves this issue. I am still tinkering with it, but in the meantime I have been using standard 5-way switches like these ones: Thru-hole 5-way Navigation switch : ID 504 : $1.95 : Adafruit Industries, Unique & fun DIY electronics and kits 
Even cheaper copies are available from ali express, etc. These switches are pretty good, but I will continue trying to make the alps switches work perfectly!

How is that possible?! The switch is not cheap. Is it a mechanical or an electrical problem within the switch?

[Bucic]

Good news and bad news.

The good news is the work is proceeding. The legs for the base turned out perfect, joints so tight I get a BOING! when I hit it. Note to self: reclaimed wood is a waste of time.

As for the 3D no-name printer I treated it to an overhaul. I detected a sneaky malfunction, replaced the bearings and fixed a 1 mm dip in the bed. No wonder leveling was inconsistent.

The bad news is that despite all my efforts I did find a job. All the consequences with regard to the "simpit time" are given, naturally.