noob question: low speed ramjet

[cam]

Would it be possible to design a ramjet with between 200 and 500 lbs of thrust at highway speed (80 to 130 km/h)? I think it would be cool to have one of these attached to the roof racks of a car to give a little extra power in the passing lane, not to mention the looks on peoples faces as it roars past them :twisted:

[heada]

I don't know if it'd be impossible, but from what I have read and seen in other ramjets, thrust is directly proportional to speed and entrance area. In order to have a ramjet produce 200 lb of thrust at 200mph (faster than highway speeds but about the slowest you can get one to work with positive thrust) it would need an entrance area of just over 200 sq inches. This would give a combustion chamber diameter of about 30 inches and a length of over 90 inches. The amount of steel required for something of this size would negate the thrust generated from it. It would simply weigh too much.

-Aaron

[Zippiot]

500 pounds of thrust is prolly about 6 times what the avg car motor can output...

To be efficient and for best results 200 mph is the recomended min speed, the faster the better gives a bigger pressure boost.