Intrument Panel Thickness in Aluminum, Glass, and Carbon

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Marc Zeitlin

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Trying to get dimensional info on the Rack for the Avidyne IFD440. If anyone has data or a drawing of it, I sure could use it to make sure I have enough room set aside for it.
Download the IFD440 installation manual - all dimensions and drawings are in it. If you can't find it online, drop me an email and I'll forward it to you.

Marc, I assume you are using #6-32 screws for attaching the aluminum to the fiberglass and hanging the avionics to the aluminum?
I use 10-32 torx drive button head screws to attach the AL panel to the glass IP stub or tabs, with clickbond nutplates. I generally use 3/4" AL angle extrusions from the airplane department of Home Depot to mount the avionics trays to the IP - all avionics (at least all that I've worked with) use 6-32 flathead screws to attach the tray to <something>, and the <something> I use is the angle extrusions. I put 6-32 nutplates on the fore-aft extrusion surface so that the tray attaches to it easily, and then I put either 8-32 or 10-32 nutplates on the left-right surface of the angle extrusion to attach the extrusion to the IP. If I was confident that the PEM inserts that FPE can install on the fwd face of the panel were strong enough, OR if I wasn't cantilevering the trays off the panel, I might be willing to use PEMS and nuts to hold the angle extrusion onto the fwd face of the panel, just to eliminate screw heads from the IP and make it look a bit cleaner. But I'm not and I don't, so I haven't :) .

I use 6-32 where I have to, but I like the larger screws because the 10-32's will match the perimeter screws, and the 8-32's - well, they're almost 10-32's. Idiosyncratic, I know.

On COZY's, generally I'll attach the AL IP at the perimeter on the sides, to the center pedestal, and depending upon how much of the fiberglass panel I can salvage, to the glass near the top as well - this is because the glass panel has two transverse stiffeners just above the leg holes and right near the top of the panel, and these substantially stiffen the panel structure if I can keep them. If I can't (and sometimes even if I can) I'll use an AL angle (again, from HD) to connect the IP to the next bulkhead fwd, wherever it's convenient and doesn't interfere with the EFIS's, to also substantially stiffen the panel. I think you can see some of this in the pics below.

I have been trying to figure out how to transfer the shape of my panel (in SolidWorks) to .dxf files, and my quarter ellipses at the upper left and right are refusing to make the trip into .dxf. Anyone with any hints on that? I am afraid I may have to learn DXF. Hints please.
Create a 2D drawing of the panel outline, and then export it to either DXF or IGES. IIRC, FPE can import either one.

As it turns out, just yesterday I finished up a full Garmin G3X panel in a COZY MKIV (Tim Andres OSH award winner from 2012, now owned by other folks) using all the techniques described here. You can see pics of the teardown/install sequence here:


Happy viewing.
 

wsimpso1

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Download the IFD440 installation manual - all dimensions and drawings are in it. If you can't find it online, drop me an email and I'll forward it to you.
I did spend quite a bit of time on Avidyne's website to do just that. When asked Avidyne's website and support folks were - unsupportive. But I did find it online and share it here:


Nice doc, except it still does not say how wide the outside of the tray is, so I am left guessing. You would think that they would want people to know the size of their stuff when designing an instrument panel for their stuff... Anybody know the outside width of the tray for the Avidyne IFD440 of 550?

I use 10-32 torx drive button head screws to attach the AL panel to the glass IP stub or tabs, with clickbond nutplates. I generally use 3/4" AL angle extrusions from the airplane department of Home Depot to mount the avionics trays to the IP - all avionics (at least all that I've worked with) use 6-32 flathead screws to attach the tray to <something>, and the <something> I use is the angle extrusions. I put 6-32 nutplates on the fore-aft extrusion surface so that the tray attaches to it easily, and then I put either 8-32 or 10-32 nutplates on the left-right surface of the angle extrusion to attach the extrusion to the IP. If I was confident that the PEM inserts that FPE can install on the fwd face of the panel were strong enough, OR if I wasn't cantilevering the trays off the panel, I might be willing to use PEMS and nuts to hold the angle extrusion onto the fwd face of the panel, just to eliminate screw heads from the IP and make it look a bit cleaner. But I'm not and I don't, so I haven't :) .

I use 6-32 where I have to, but I like the larger screws because the 10-32's will match the perimeter screws, and the 8-32's - well, they're almost 10-32's. Idiosyncratic, I know.
That voice of experience, I will just apply.

On COZY's, generally I'll attach the AL IP at the perimeter on the sides, to the center pedestal, and depending upon how much of the fiberglass panel I can salvage, to the glass near the top as well - this is because the glass panel has two transverse stiffeners just above the leg holes and right near the top of the panel, and these substantially stiffen the panel structure if I can keep them. If I can't (and sometimes even if I can) I'll use an AL angle (again, from HD) to connect the IP to the next bulkhead fwd, wherever it's convenient and doesn't interfere with the EFIS's, to also substantially stiffen the panel. I think you can see some of this in the pics below.
All that makes a ton of sense. I have a pretty sturdy panel and was planning to bond a fiberglass channel (made for the purpose) to the back in four places, oriented vertically, one on each side of the GPS/NAV/COM, one outside of the Dynon displays. They were planned to be 3/4" wide too. The aluminum IP face would have been just attached with screws and ClickBonds around the edges and along all four channels. Now I am thinking how I can make the panel as stiff and strong as what you propose. Thinking maybe the fiberglass channels can do it...

Create a 2D drawing of the panel outline, and then export it to either DXF or IGES. IIRC, FPE can import either one.
Suggestions are generally to make a 2D drawing from my 3D parts before trying to make it jump to FPE. Lots of things to try, and I will share the workaround that works.

As it turns out, just yesterday I finished up a full Garmin G3X panel in a COZY MKIV (Tim Andres OSH award winner from 2012, now owned by other folks) using all the techniques described here. You can see pics of the teardown/install sequence here:


Happy viewing.
Serious WOW! That gives me all sorts of thing to think through. Thanks again for the huge support.

Billski
 

Pops

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Bearhawk instrument panel, .063 2024-T3. With a 1.5" lip on the bottom. Also made a removable panel on top of the instrument panel.
 

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Marc Zeitlin

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Nice doc, except it still does not say how wide the outside of the tray is, so I am left guessing.
Well, not directly, but in Figure C - 35 on page 136 of 213 in Revision 09, it shows the IP cutout needed if you install the tray from the front, rather than the back. This outline is just barely larger than the tray itself (since the tray has to fit through it to get in front of the panel). So that would be the 4.61" x 6.32", with the 0.050" x 0.75" cutout below the center for the lock.

Serious WOW! That gives me all sorts of thing to think through. Thanks again for the huge support.
De Nada.

Just as a calibration, the IP/electrical system replacement on that plane was just about 200 hours, give or take.
 

wsimpso1

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Well, not directly, but in Figure C - 35 on page 136 of 213 in Revision 09, it shows the IP cutout needed if you install the tray from the front, rather than the back. This outline is just barely larger than the tray itself (since the tray has to fit through it to get in front of the panel). So that would be the 4.61" x 6.32", with the 0.050" x 0.75" cutout below the center for the lock.

De Nada.

Just as a calibration, the IP/electrical system replacement on that plane was just about 200 hours, give or take.
I saw that difference in the drawings. 1/16" more to get the tray in too? Either the tray is mighty thin or that leaves the cutout with a big gap to the parts protruding through to the dressy side of the panel. Looks like I will take measuring tools with me to the FBO maintenance shop and hope to measure some reality (there is an new IFD440 in our Archer, which is down for annual). I sure wish I had figured out I needed this info two months back, when the parts were sitting on the bench...

Maybe a pro like Marc Zeitlin can do it in 200 hours. ;) I was figuring on this first timer spending more like three months on the task.

Billski
 

Marc Zeitlin

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I saw that difference in the drawings. 1/16" more to get the tray in too? Either the tray is mighty thin or that leaves the cutout with a big gap to the parts protruding through to the dressy side of the panel.
Yeah, trays are pretty thin. 90% of it is 0.032" or 0.045" AL, and there are just a few places where the AL is doubled up on some trays. There are NOT large gaps, and if you make the hole in the panel too large, the bezel of the instrument will NOT cover up the gap. You want the hole in the panel to be the absolute smallest it can be - I always use the smaller hole definition and do NOT slide the tray in from the "dressy" side of the pane (aft side). In some planes, this may not be possible, but in canards, it always is.

Maybe a pro like Marc Zeitlin can do it in 200 hours. ;) I was figuring on this first timer spending more like three months on the task.
Hah. 200 hours assumes you purchase a harness, VERY well defined with (in this case) zero point geometry definitions for harness leg lengths (or a bus architecture, if that fits the needs better), from SteinAir (or a functional equivalent, but I've used them for four installs and we have a good working relationship, plus Stein Bruch is a very funny guy).

My customers couldn't afford to pay me to pin a whole harness, plus, it would have errors to debug - Stein rings it out and configures the components and harness. You also get a complete schematic from them, with all connectivity defined. Not to say that there are never errors in either the harness or the schematic - sometimes there are, and I've got to fix them, but they're relatively few and far between, and it's still better and cheaper than I could do.

If you're going to pin every connector and run every wire yourself, yeah - at least double that time. That 200 hours was spread out over 8 weeks - March 12 to May 8. I don't work 40 hour weeks :).

I don't think I've posted this here previously - this is a link to MY plane's electrical system definition, with all drawings and schematics:


So you can see all the documentation, both from me and from Stein. Yeah, I went nuts.
 

Yellowhammer

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I looked and could find very little on this topic. One thread said sailplanes are using 5-6 plies of 200 g/m^2 (6 oz/yd) glass cloth, while Jarno indicated less in graphite. But these are smaller panels.

I know, I am a composites analysis guru, why do I not just figure it out? Truth be told, if a convention already exists, I like to go there instead... Besides, it mostly comes down to having enough stiffness, and for this, I am betting that empirical processes mean more than my use of SolidWorks...

So, my panel is 46" wide, will have a couple 10" Dynon displays, an IFR GPS/NAV/COM, a backup EFIS, and some smaller stuff. What thickness is being used for this sort of thing in aluminum, glass composite, and graphite composite?

Billski
Excellent question.
 

wktaylor

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wsimpso1… some thoughts are not very funny, nor wise, to be spoken out loud in an amateur setting...

"...airplane department of Home Depot..."

NOT knowing what You are putting in an aircraft is unwise... even seemingly trivial parts...

Aviation Itself is Not Inherently Dangerous.jpg
 

Marc Zeitlin

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wsimpso1… some thoughts are not very funny, nor wise, to be spoken out loud in an amateur setting...

"...airplane department of Home Depot..."

NOT knowing what You are putting in an aircraft is unwise... even seemingly trivial parts...
Feel free to quote me directly and reply directly if you've got an issue with something I said - I'm happy to admit when I'm wrong if someone can point out why that's so.

But what if you DO know what you're putting in an aircraft and you still got it from Home Depot?

In the case of the angles I use, I'm going for stiffness, not strength - the angles are WAY stronger than necessary to support the few lb. of weight, even at 4 - 6 G's. All aluminum has the same modulus of elasticity, within a percent or so, so as long as it's strong ENOUGH, any AL will do for these purposes. And since these pieces are internal to the airplane and never exposed to the elements, I don't really care about environmental corrosion resistance, but could paint them if I did.

Now, the Home Depot Everbilt angle material is almost exactly the same 6063T52 that ACS sells as an angle or channel (which I use for capturing the heads of the wing attach bolts inside the spar) - it's 6063T5. The strength is at least 20 ksi, which gives huge safety factors for attaching an instrument tray to an instrument panel, or to stiffen the IP when connecting it to another bulkhead (which were the contexts in which this "Home Depot" material was used - nowhere did anyone mention "wing spars" or "control surfaces", in which case something other than "eyeball engineering" would obviously be required).

So is it OK with you if I use that, and recommend it for this purpose? Or would you rather that I wait a couple of days to mail order essentially exactly the same thing from ACS for 3X - 4X the price, once I get through with shipping? Since obviously an aircraft parts supplier's material would be more appropriate...
 

TFF

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I think I would use some of that green steel T shaped fence post; the kind that has the chunk of concrete stuck on it, usually found thrown behind your grandma’s garage. Way cheaper than HD.
Most trays have provisions for a back stay rod or some kind of hanger. Heavier items, like a Garmin 430 or a regular radio stack is rarely cantilevered. Modern electronics like a G5 is only inches deep and doesn’t need much support. The radios seem to be keeping the standard depth, just because they don’t have to reinvent the wheel. The modern flight displays are all over the place on depth.
 

wktaylor

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Mark Zeitlan…

My apologies for miss-attributing wsimpso1 for Your original quote "...airplane department of Home Depot...".

I located Your original statement... so You certainly deserve the credit.
 

rv7charlie

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Billsky,
The 440 fits a Garmin 430 tray (they periodically offer 'trade-in'/upgrade deals where you don't get a tray with the new 440). The Garmin tray is made to mount *behind* the cutout; its width is 6.320". The Garmin 430 *faceplate* is 6.250", so if you mount the Garmin tray through the faceplate, instead of behind it, the Garmin faceplate won't cover the hole. I don't have the 440 manual on hand, so I don't know the width of the 440 faceplate.
1621021624947.png
 

rv7charlie

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Oh, and a heads-up on the concept of various stiffeners, etc on a panel. *Everything* you do structurally, restricts panel space and usability. A lot. Van's stock instrument panel is 0.063 (probably 2024), with a 1" flange bent on the bottom edge. The top has a 3/4" aluminum angle riveted as a stiffener (can't be bent because the top of the panel is curved). The riveted top angle costs 3/4"+ of vertical space. If a bottom flange is riveted instead of bent, that costs more vertical space. I've replaced about 1/3 of the panel (containing an 8" EFIS) in my RV6 with 0.50 aluminum of unknown pedigree but much lower strength than the original panel, with no ill effects. There is a vertical reinforcement at the joint between the new section and the original panel segment, and the original flange across the bottom of the panel was retained.

There are two vertical stiffeners that are actually the aft ends of two airframe ribs, but it is acceptable to cut/move them to where ever is convenient (even delete, in some cases). They *always* fall within the cutout of at least one instrument. Their true purpose is not so much to stiffen the panel for installed instrument weight, but to prevent fore/aft flex. The aluminum radio stack attach angles cost 3/4" on each side of the stack. Etc etc.

FWIW....

edit: TFF makes a good point about rear (forward?) support for long, heavy avionics. In the RV's, the 430 extends far enough forward to protrude through the 'subpanel'; the partial bulkhead that's slightly forward of the front of the windshield. I made a bracket attached to the subpanel that supports the connector end of the 430, and in turn, the transponder, etc, that are stacked on it. The 430, etc simply rests on the bracket, allowing me to pull the entire panel/radio stack without dumpster diving. I'd be somewhat concerned about fatigue to the panel if it was asked to support the cantelevered radio stack without assistance.
 
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dwalker

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When I was a younger lad, I built some carbon fibre splitters (undertrays) for the cars we were running at the time to the very limit of the rules. Something along the lines of 2" from the bumper, had to be a flat plane and could not extend rear of the front axle centerline. Most of the teams were using plywood, some, including the team I joines, were using aluminum. For a splitter to be effective at speed it needs to at least be able to support the weight of a full size human (lets say 200lbs) standing on the splitter while in place, with no deviation.
I built carbon fibre over nomex honeycomb core material using aluminum hardpoints vacuum bagged on a large plate glass surface, that was really super stiff and very very light. Worked awesome, dropped 10lbs or more from the front of the car, and you could throw the thing like a frisbee if you wanted. IIRC I even built a couple using foil covered foam, a couple of heatguns, and a temp probe on my meter to heat cure while bagging, which was amazing.

The reason I mention all that is my Dragonfly shockingly has a honeycomb core composite for bits of the interior. Again, super light, amazingly stiff and strong. If I can find some core material, I will likely do the Dragonfly and Long-EZ panels out of vacuum bagged honeycomb core and carbon with hardpoints for mounting, thinned out "molded" areas for switches/breakers, and might even be able to build another heat box.
Obviously, way easier to just cut some aluminum sheet up, but as long as I have the foam and epoxy out might as well give it a go!
The first picture is me working on a mold for a "lip"from the splitter up to the lower bumper on my glass surface, the second is the AL splitter as used prior to my becoming involved.
 

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wsimpso1

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Mark Zeitlan…

My apologies for miss-attributing wsimpso1 for Your original quote "...airplane department of Home Depot...".

I located Your original statement... so You certainly deserve the credit.
Uh, I feel the same as Marc does on this topic... This is a part added to make something stiffer for the human factor issue of the panel moving too much under vibration and contact - strength only enters with regard to fasteners, and they are way more than adequate too.

If the person doing the design does the engineering correctly, you could almost make parts like this out of cardboard. Do the engineering badly, and the best most expensive stuff in the world will still result in crap... Let's have a little faith in the chops of the folks involved on bolting this together securely.

Billski
 
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