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Engine basics => Engine set up tips => Topic started by: Peter in Fairfax, VA on August 07, 2021, 01:26:56 PM
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What filament would be best for engine mount shims, if any? I could use metal, of course, but wonder if engine heat would melt the more heat-resistant filaments. The engine in question is a Brodak 40, which does not sit at the right height in my Vector.
Thoughts?
thanks,
Peter
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What filament would be best for engine mount shims, if any? I could use metal, of course, but wonder if engine heat would melt the more heat-resistant filaments. The engine in question is a Brodak 40, which does not sit at the right height in my Vector.
Thoughts?
thanks,
Peter
I think that it's worth a try. The bottom of the crank case doesn't get that hot while the engine is running and most of the heat you would feel after a flight is heat soaking down from the upper part of the cylinder. You should be able to make them with the correct hole locations, or even just a dimple at the correct location so you can drill the holes size you need or want. Let me know how the work of i can test some for you on a profile model
Type at you later,
Dan McEntee
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Peter
if you can get some the thickness youneed, phenolic (spelling) will work nicely.
Carl
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Personally I think I'd want something stronger than a thermoplastic (meltable) filament.
And I love using phenolic, so +1 to Carl's suggestion! It's almost as chemically resistant as CF-epoxy, much more workable, and plenty strong enough for an engine shim.
If I wanted something 3D printed, I'd get it printed in resin. There's a ton of places that'll do that for the right amount of $$.
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ABS should suffice. Mind you, I haven’t tried it.
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First concern would be stiffness. All plastics are generally fairly compliant. I'd use aluminum myself but that just me. Carbon fiber would be good as well as Garolite (phenolic). I've been making some 3D parts with carbon fiber impregnated nylon Nylon X which would do the job but it's pricey as material isn't cheap and you need hardened nozzles to use it. With all of the above options in my shop, it would depend on my mood which one I would choose but more than likely it would be a aluminum.
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"Filament?"
"Material."
ABS will work, various thicknesses and easy to cut/drill. Layer pieces up for fine adjustment.
I've used ABS behind R/C motor mounts to add offset.
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Aluminum or phenolic. These parts are simple enough that they can be made with a hacksaw and a drill in 20 minutes. Leave 3D printing for something more complex.
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SIG offered an engine support, primarily targeted to profiles I would guess, and it was some sort of black plastic and shaped like a squarish "C". I've used them and never noticed them compressing or changing in any way. This was at a time when SIG did almost all of their own plastic molding, so it was probably the same plastic (black) as their 4" bell crank. Top Flite used to make a similar product but smaller and intended to be used as one under each side. I have some of those also. Sterling , I think, used to make some plastic wedge supports the same way and were in varying degrees of angle to set engine offset for a profile. These were white nylon, it looked like, and while they worked OK, they were too thin and flimsy and would distort if they were not on a solid, smooth surface. Given that, though, engine heat didn't seem to affect them. If I were to try to 3D print something it would be similar to the SIG offering with about a 1 degree offset angle and make them in specific widths for specific brands of engines.
Type at you later,
Dan McEntee
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Brodak also carried 'Thrust Wedges' with an assortment of varying degrees offset for profile applications.
STAY SAFE & "Tight Lines!"
Wes
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Dan,
They were made from a plastic called Ryonite (sp) glass reinforced injectable plastic that worked very well and had
plenty of strength. I don’t remember who made it but it wasn’t hard to find so we ordered a few bags, we made a number of injection model parts from it, including motor mounts, 4” bell-cranks, thrust wedges, and control horns. What was cool when they were dropped on the floor they would almost ring like metal parts would.
Later,
Mike Pratt
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Rynite is a high temp, high stiffness Dupont product.
https://www.dupont.com/products/rynite.html
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While I cannot comment on your exact engine, PETG would be what I would use. I have made 1/2a TD engine mounts and it appears to hold up well. I also have made up and used PLA for 1/2a engine spacers as well, but these are for a plastic backplate.