Carbon Fiber Ramjet (RC)

Thanks all for watching

Skip to 4:40 for the testing

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0:00 Intro
0:48 Build
4:40 Test 1
5:22 Test 2
5:58 Test 3 (No Aerospike)
7:03 Outro

[AstroCharlie]

Instead of trying to achieve supersonic inlet conditions with an EDF (quite challenging) you can use a compressed air supply. With a pressure ratio of slightly above 1.8 and a small enough choke (or high enough flow rate) you can get sonic velocities. A large compressor is cheaper than a moderate sized EDF so I believe this is fairly economical as well.

[Willj]

Honestly this is very impressive, its been amazing to see how much you have developed this design and I look forward to seeing where you take it next.

[noutram]

Hi, love this. Using Furnace Cement on CF -great idea!
Even to duplicate jet engine compression ratios would take 3 or 4 stages of alternating rotating EDFs. You might be able to use a centrifugal compressor on the inlet -there's a reason why Frank Whittles engines had a centrifugal compressor 1st stage. I think it highly unlikely you can achieve hypersonic compression ratios without a vastly more expensive setup.

[Yamagatabr]

I'm a simple man, if I read "Carbon Fiber Ramjet" I click it.

[jamesjudson]

love the video, I would recommend switching to a compressor fan instead of the EDF's. It might turn out closer to a turbojet (because of the compressor, But I think that high pressure air is always favorable over high speed air (especially when it comes to ignition).

[FodderBoi]

It's nice to see someone not melting down their engine every test. I think you could get more thrust if the diameters of the inner and outer casings are closer. Like putting your thumb on a garden hose...bernoulli's principle!

[Awesomlypossom]

Super cool! if i remember right, EDFs don't make too much pressure. Looking into turbo chargers might be a path towards higher pressure/speed.

[gabrielbennett]

Notice how the burner keeps blowing out? You might need to add a flame holder to prevent that. It would also increase combustion chamber pressure. A simple steel baffle plate or peforated cylinder would do. Just get a stainless steel dishwasher silverware holder or soap holder from Walmart or wherever and drill a few holes in it to start with, test fire it and add more holes as needed until it works right.

[mellis]

So Cool. I think that in this type of design the combustion should happen inside of the shielding of the EDF airflow. The envionment air is static. The EDF flow is second fastest. The hot combustion should be fastest and inside the velocity wall of the EDF fan. This requires two air flows. One for the EDF and a second for the Hot ICE combustion. I love what you are doing. Keep Going. Thrust is about mass air flow. On a small diameter that means very high velocity.

[thunderBOOM]

90k rpm can be achieved with some BLDC motors i think, you can even wind your own and use maybe a less permissive core material, like 15 percent ferrite PLA (if you do you will need to make a decent driver circuit from scratch for the required voltage to get it up to that speed cause i doubt those themselves are made either)
as for the impeller, you could adapt the geometry to fit in an impeller from a used up car turbo ( gonna be a pain to get the right dimensions without the fin profile measures from paper tho) and while youre at it change the inside geometry to make a second air intake like a venturi pump, so it makes an air vortex that cools the inner walls and generates "suction" forwards while its at it.
if you want it to run on fuel only, theres some recent vids on a trick the navy used for better performance on their jets, basically split the compressor axis (one inside another) to different stages, so the outwards one was being driven by the higher speed outlet stage gas while the inwards one was driven by the high pressure combustion stage gas.

[nickhockings]

You would get stronger parts and more precise geometry, and therefore better aerodynamics inside your engine if you filament wind on 3D printed mandrels. You can remove the mandrels by baking in an oven to let the molten plastic flow out.

[Nugget]

I'm sure you have considered this but you could have a centrifugal pump for more pressure.

[haydennorris]

Maybe a more powerful electric motor with a sort of long multiple row fanblade setup like a jet engine compressor would work. Then just squeeze the air to a tiny area to get the most air speed. You wouldn't need supersonic fan blades if you could supply enough static pressure to use a nozzle to accelerate the air. You may have to use carbon fiber and resin to make each fan blade. You could try making a thin walled hollow 3d print then coating them in fiber and resin to make your blades. It would be a lot of work but I don't know of any lightweight compressor blades for sale as hobby stuff. You could also try a massive air compressor for testing. Maybe a bunch of progressively smaller diameter electric hobby motors/fans would work. Either way good luck and I will continue to watch your career with great interest.

[tomo_ka]

in theory you could build a compressor

[elpocasombra]

Your channel reminds me of integza, great content btw, got a new sub from me

[DamienKoda]

"it's not perfect" 😆 indeed it isnt far from perfect, good video anyway

[yelectric]

Maybe some stators past the edf and more even fuel injection could help performance. Also, perhaps this can use an EDF to get to speed but become a ramjet in the air after initiating a dive in the flight profile to get sufficient compression and use a ramjet to sustain that speed

[TheSLOShadow]

From what i lmow of ramjet... U kinda need supersonic air for it to work.

A very big compressor and ear plugs maybe.

[samspade]

Would it help to have a variable exhaust nozzle? Something simple as 2 half shells on a spring loaded hinge.

[cicADA]

maybe a small jet engine would be able to achieve the required pressure for efficient combustion?