Doggzilla
Well-Known Member
So was just doing some math after reading up on the XV-5 Vertifan, and found something that might be of interest.
The Vertifan drives a pair of fans that are designed like giant turbochargers. The fans have a hot section driven by two 2600lb thrust jet engines, and produce 7500lbs of thrust in return. Of course the thrust is MUCH slower, but still significant.
Here is the issue. If we were to take a crappy RC jet engine that is borderline useless and convert it to use a system like this, it suddenly THEORETICALLY surpassed the performance of a prop.
For example, a Kingtech K-120 provides about 70lbs of thrust for 6gph of fuel. Modified with a fan it should produce over 200lbs. Take a pair of these and you have 400lbs.
Most business jets have a thrust to weight ratio of about 0.30, so an aircraft with 1330lb gross weight would have the same power to weight with the pair of these modified engines.
Thats a 1330lb aircraft capable of business jet like performance on TWELVE GALLONS PER HOUR. That would be impressive at even twice the consumption.
So there is definitely something that is not adding up here.
The Vertifan drives a pair of fans that are designed like giant turbochargers. The fans have a hot section driven by two 2600lb thrust jet engines, and produce 7500lbs of thrust in return. Of course the thrust is MUCH slower, but still significant.
Here is the issue. If we were to take a crappy RC jet engine that is borderline useless and convert it to use a system like this, it suddenly THEORETICALLY surpassed the performance of a prop.
For example, a Kingtech K-120 provides about 70lbs of thrust for 6gph of fuel. Modified with a fan it should produce over 200lbs. Take a pair of these and you have 400lbs.
Most business jets have a thrust to weight ratio of about 0.30, so an aircraft with 1330lb gross weight would have the same power to weight with the pair of these modified engines.
Thats a 1330lb aircraft capable of business jet like performance on TWELVE GALLONS PER HOUR. That would be impressive at even twice the consumption.
So there is definitely something that is not adding up here.
