Cowl Air Scoop

[Mark Dickens]

Has anyone modeled an intake air scoop for the nose bowl? This is one of my goals for the Companion. I got two spools of PAHT-CF for Christmas and I'm imagining a nicely faired "ram" scoop interfaced with my horizontal intake manifold. Not that it would alter the speed of the plane, but it would look cool

[Mark Dickens]

I modeled an air filter holder and base plate that bolts directly to my fuel injector (RSA-5 mount). The filter canister is modeled to hold a K&N RU-2790 filter. A side inlet will be plumbed to the bottom of the left baffle inlet ramp. I've printed a prototype and it just fits. I may elect to put a small bump on the lower nose bowl for clearance, but overall, I'm pretty happy with how it came out. I've sent it out to be SLS printed using PA12. When I get it, I will post a photo of it installed.

canister 2.png canister.png

[huntaero]

For our 4A we used an IO-520 intake tube and modified to adapt our airbox to the forward baffles which are the same size as the RSA fuel servo inlet dia, used two for redundancy, similar to the Cessna U206. Made to fit a K&N air filter and installed an alternate air-door manually controlled (canadian requirement). We used an Air flow performance 110-degree intake elbow with K&N E-0995 air filter and installed a 4 in prop extension for clearance, makes for a nice clean cowling.









SKS_5893b.jpg

[Bcone1381]

I'd like to encourage our group to be aware and exercise caution with 3d printed parts in the engine area due to material ability to handle high heat.

Be cautiously curious, understand the environment, and the nature of the material under high heat and do some testing. Temperature Testing on material is very satisfying and not a lot of time or effort. Set some temperature thresholds limits that are rather conservative.

Within the last year or so there was an accident of an experimental aircraft...If I recall correctly.... at least part of the intake assembly was beautifully fabricated using a 3d printer. The part was under higher-ish heat conditions. The suction force in the engine intake collapsed after it was softened by the heat. The collapsing blocked airflow to the engine and resulted in engine failure.

I have a turkey roaster....If anyone want to send me some 3d printed material I can test it for you. I also have thermocouples and readers. I'll lend them out too. This allows a builder to collect real temperature data inside the engine cowl.

[U2fletch]

Mark is sending this part out for SLS printing with a high temp material, so is exercising good choice of material. You are correct about the crash caused by the intake part collapsing. Using a thermoplastic above its rated temperature is a bad idea.

[Mark Dickens]

Nylon 12 has two things going for it, a relatively high heat deformation temp of between 140-147C, and when it does deform, it does so VERY slowly...in addition, this is used for air intake and would be in a relatively cool temp environment. If I have a situation where that environment is at 284F or higher, I have much bigger issues at hand.

I am using the same material and process for the oil cooler shroud too, which will be in a hotter environment, but again, I surely hope that the air cooler is not getting 284 F from cylinder fins!

[Mark Dickens]

Here's a good write up about glass transition temps and heat deformation: https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-print-tips-archive/glass-transition-temperatures-not-what-they-seem

And https://vansairforce.net/threads/3d-.../#post-1892783. Scroll to post #18,,,good stuff there as well.

[Mark Dickens]

I received my filter canister today. The filter fit perfectly in the canister and with the 3" inlet, I think the engine will breathe well.

IMG_2302.jpg

Not that this is some kind of brilliant design, but if anyone wants the files, let me know.

[DBeaulieu]

Mark, curious about your thoughts in making that a side inlet? I have horizontal induction with FM150 fuel servo (RSA5 I believe) and hadn't thought about that configuration...looks interesting. I am just getting to this part in my Patrol project and still doing the "figuring out" part.

[Mark Dickens]

My objective was to see if I could avoid having to make cowl mods, like a ram air inlet. I did one on my RV-8 and it took a lot of time. This configuration mimics the Vans inlet which is also tied to the left baffle inlet ramp. When you opt for fuel injection and a horizontal manifold, you aren't left with much space inside the cowl. This set up leaves about 1/2" of margin. Plus, I like to come up with my own "solutions" and it's been fun learning Shapr3D to make a usable part.