khorton
New Member
I am very happy to learn about the HSI 34 expansion module, as I have a GNS 430 that would need to use with an eventual D-10A as an EHSI. However, I am quite dismayed to learn how large the HSI 34 is. I have some space left in my panel, but not nearly enough to fit this monster in. I would need to cut a whole new instrument panel, get it powder coated and silk screened, etc 
I know Dynon is working on other expansion modules, so perhaps you have something in the works that would better meet my needs. If not, I offer the following comments as ideas for future products.
1. I suspect there are many people like me - they have a GNS 430, want to feed it to a Dynon product, but have no more panel space available. Why not make an interface box with no instrument panel interface? Sure, you wouldn't get the nice knobs, or the bearing needle switches, etc. But, you could at least use a GNS 430 without sacrificing any panel space.
2. Why not make a smaller version of the HSI 34? Does it really need to be so big? As a reference, I measured the spacing between adjacent knobs on a Canadair Challenger CL-604 - the knobs on the lighting control panel are 0.5" diameter, and spaced side-by-side on 1.333" centres. The only vertically stacked knobs I could find are of similar diameter, but spaced 1.5" vertically, centre to centre. It should be possible to make much smaller, but still usable, control panel.
3. If you can't make the HSI 34 smaller because you need to the volume to fit all the electronics, then how about making a smaller control head that just has knobs and buttons. It would connect to a remotely mounted box that had the bulk of the electronics. It should even be possible to make this remote box be the same one as discussed in comment 1. If a knob and button box was connected to the remote box, it would respond to them. If no knob and button box is connected, the remote box simply interfaces the GNS 430 to the HSI. If you did this, I would purchase the remote box so I could feed a GNS 430 to a D-10A. Later, when I was prepared to redo my panel, I would purchase a cockpit control panel to hook up to the remote box.
4. You could publish the spec to allow third party knobs and buttons to connect to the remote box mentioned in comments 1 and 3. This would allow installers to use buttons and knobs that matched the rest of the instrument panel.
5. As others have mentioned, a horizontal orientation would be popular. But, for those with D-10As, it would be a bonus if the expansion module width matched the width of a D-10A. That way the expansion module could be mounted right above or below a D-10A. There should also be an available spacer that would go between the expansion module and the instrument panel, to put the aft face of the expansion module in the same plane as the aft face of the D-10A.
6. A cockpit control panel with just the heading knob, course knob and the bearing and nav source buttons would be nice, with a second control panel that just has a Value knob. The first control panel would be mounted near the EHSI, and the second one near the EADI.
7. I saw an interesting cockpit control on the Dassault Rafale demonstrator way back in 1988. There was a knob similar to your Value knob, but there was also a concentric outer ring. You selected which item you wanted to change by turning the concentric ring. Once you had the correct item selected, you spun the knob to change the value. When you had the value you wanted displayed, you pushed the knob to enter the value into the system. A few seconds after you pushed to enter, the system timed out, and the data entry field on the HUD would disappear. If you turned the Value knob again, the data entry field on the HUD would be displayed again, with the item that was last used displayed. If you wanted something different, you would turn the outer ring to cycle through the different items. You could use a similar interface with the Value knob on your system. This would be quicker and easier than using the buttons on the EFIS to select the item to be changed, then moving the hand to the knob to change the item.
I know Dynon is working on other expansion modules, so perhaps you have something in the works that would better meet my needs. If not, I offer the following comments as ideas for future products.
1. I suspect there are many people like me - they have a GNS 430, want to feed it to a Dynon product, but have no more panel space available. Why not make an interface box with no instrument panel interface? Sure, you wouldn't get the nice knobs, or the bearing needle switches, etc. But, you could at least use a GNS 430 without sacrificing any panel space.
2. Why not make a smaller version of the HSI 34? Does it really need to be so big? As a reference, I measured the spacing between adjacent knobs on a Canadair Challenger CL-604 - the knobs on the lighting control panel are 0.5" diameter, and spaced side-by-side on 1.333" centres. The only vertically stacked knobs I could find are of similar diameter, but spaced 1.5" vertically, centre to centre. It should be possible to make much smaller, but still usable, control panel.
3. If you can't make the HSI 34 smaller because you need to the volume to fit all the electronics, then how about making a smaller control head that just has knobs and buttons. It would connect to a remotely mounted box that had the bulk of the electronics. It should even be possible to make this remote box be the same one as discussed in comment 1. If a knob and button box was connected to the remote box, it would respond to them. If no knob and button box is connected, the remote box simply interfaces the GNS 430 to the HSI. If you did this, I would purchase the remote box so I could feed a GNS 430 to a D-10A. Later, when I was prepared to redo my panel, I would purchase a cockpit control panel to hook up to the remote box.
4. You could publish the spec to allow third party knobs and buttons to connect to the remote box mentioned in comments 1 and 3. This would allow installers to use buttons and knobs that matched the rest of the instrument panel.
5. As others have mentioned, a horizontal orientation would be popular. But, for those with D-10As, it would be a bonus if the expansion module width matched the width of a D-10A. That way the expansion module could be mounted right above or below a D-10A. There should also be an available spacer that would go between the expansion module and the instrument panel, to put the aft face of the expansion module in the same plane as the aft face of the D-10A.
6. A cockpit control panel with just the heading knob, course knob and the bearing and nav source buttons would be nice, with a second control panel that just has a Value knob. The first control panel would be mounted near the EHSI, and the second one near the EADI.
7. I saw an interesting cockpit control on the Dassault Rafale demonstrator way back in 1988. There was a knob similar to your Value knob, but there was also a concentric outer ring. You selected which item you wanted to change by turning the concentric ring. Once you had the correct item selected, you spun the knob to change the value. When you had the value you wanted displayed, you pushed the knob to enter the value into the system. A few seconds after you pushed to enter, the system timed out, and the data entry field on the HUD would disappear. If you turned the Value knob again, the data entry field on the HUD would be displayed again, with the item that was last used displayed. If you wanted something different, you would turn the outer ring to cycle through the different items. You could use a similar interface with the Value knob on your system. This would be quicker and easier than using the buttons on the EFIS to select the item to be changed, then moving the hand to the knob to change the item.