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There are already a number of vendors offering Spitfire Spade Grips for decorative or flight simulator use. However as it has always been my intention to create my own cockpit from scratch so that is what I am doing. This does then offer the opportunity to integrate my own choice of sensors into the grip/handle assembly.
Jan 2021 - For those of you who are looking for a quick fix then I can thoroughly recommend having a good look at https://authentikit.org/ who has also been at this game for the past 2 years. As he appears to be a lot more more single focussed than me (I am easily distracted and wander around from piece to piece) so he is a lot further ahead on the spade grip and is already offering a finished product as free STL. He is also working on a throttle and trim wheel so I should really go back to focussing on the instruments.
I may have a look at taking his output and perform a remix - to add my park brake
Original Spade Grips, made by Dunlop, have the following manufacturers part numbers stamped on themSource: https://www.key.aero/forum/historic-aviation/23659-how-to-recognize-a-spitfire-spade-gripA.P.1086, Part 11E lists the following "ring control handles" for the Spitfire:AH2174 for Spitfire IA, IIA, VAAH8068 for Seafire, Spitfire IB, IIB, VB, VC, F.VI, VII, VIII, FIX, FXII, FXXIThe AH2040 was fitted to Hurricanes Battle, Fulmar, Lysander I and II, Skua, Swordfish and Whirlwind
Looking at the layout of the spade grip the Spitfire is very much for the right handed pilot. The brakes, camera and gun switches can only only be operated by the right hand.
I have been using this photograph (and a few others) to create a scale model of the spade grip, canon switch, and gooseneck parts of the control column. The original much larger "Cockpit Controls Of A Spitfire Fighter" image is available for purchase from "fineartamerica.com".
This photograph is quite handy as I have the blind flying panels dimensions for the mounting centres of the ADI (the square to the right of the grip) so with just a little adjustment for parallax (about 4%) I was able to get some reasonable scale measurements for the entire assembly.
I am not sure yet if I will build a full column (modelled on something like this https://youtu.be/XcKmBWGFUn8 or just an adapter ring to attach the gooseneck (the lower cream part) to my existing Logitech Pro Flight Yoke.
Whilst the finished spade grip will have the roughly the right dimensions and look correct from the front aspect, some parts will have to be added/moved to enable me to make room for the sensors.
The brake handle will require a bearing (22mm as I have plenty of those in stock), a spring attachment and a magnet enclosure. Whilst the shaft hosel will need matching mounts for the spring, a brake end stop and a hall effect sensor to detect the brake handle position.
On the photograph, directly below the gun switch is the Spitfire's camera switch. I have found several conflicting photographs showing that the camera switch can be mounted in one of 2 positions with the bracket attached either left or right of the hosel. I assume that this is pilot preference. Whilst there is no need for a camera switch in the simulator, this bracket would be an ideal place to fit a flight sim point-of-view hat switch.
In my model there is also space at the top of the shaft hosel to fit a small circuit board, for an ATTiny, that could be used to convert the gun switch, POV Switch and the brake position to a single serial cable connection at the cost of a few milliseconds game delay.
The Canon/ Gun Switch has been a fun project all on it's own. The original gun switch was pneumatically operated, you can see the 3 air pipes and their compression joints at the front of the column on the gooseneck.
I have used a couple of 13mm Microswitches and 4 off 0.5x7x13.5mm Springs from an assortment box of 250 that I bought on eBay. After I have used a couple more for the Brake lever operation I will have 244 springs remaining to find another use for !
The upper 3 parts are built as one assembly and held together by 2 off 2mm screws and a rocker pin. The two case parts are printed as part of the spade grip (hence the cable exit holes). 2 more 2mm screws hold the bottom case to the lower switch assembly plate.
I still have some easing/rounding to do on the rocker top and the upper case but I am quite happy with the results of the draft print.
The one issue that I have yet to resolve is how to implement a working 3D printed safety switch within the existing volume of the case. The original canon/gun switch has a sliding plate/switch on the lower facet of the upper case
One approach may be to use a small slide switch and to implement the safety electrically/logically rather than mechanically stop the switches being pressed.
Close up of the draft brake handle print showing the spring mount, magnet holder and bearing.
27 Nov 20 I have just been watching an excellent (but quite old) documentary on the Spitfire on YouTube. https://youtu.be/8JgyKO3WT28
Towards the end the full start up sequence is shown including a few frames on the use of the brake lever. What I had not appreciated up to then was that there is a parking brake catch that is manually applied to lock the lever with the Brakes fully engaged. This catch automatically retracts when the brake handle is pulled a second time.
My thanks to Paul Ivinson for working out the operation of the catch and finding a photograph of a Mk22/24 grip showing the catch.
https://www.pinterest.co.uk/pin/409405422352365543/
So I now have to work out some kind of simple latch/release mechanism to fit to the hosel.
The 2nd proof-of-concept print of the canon/gun switch.
The central pivot will need lowering slightly then strengthening and the casing wants some additional edge rounding. The switch mechanism plates are showing some warping from the spring pressure. But that will not be an issue on the final print as the switch plates will be strengthened by attachment to the casing and the rocker top.
Note: The casing print is also exhibiting some very mild "elephant footing", so the final print will need a little fine tuning.
Version 2 of the Parking Brake engaged
The great thing about 3D printing is just how fast you can iterate a design. So far I have made 5 versions of the brake catch, each one taking about an hour in total to modify the design, compile to an STL file, slice the STL into G-Code and then warm up the printer and print it. For a cost of 1.5 meters of filament, approx £0.09p each time.
I failed abysmally at fitting the catch with a torsion spring return mechanism. But late yesterday I had the thought - could I use the existing brake lever return spring to do both jobs ? 1 hour later and the answer is Yes!
Version 2 of the Parking Brake disengaged
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