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I have done some basic calculations into the feasiblity of a VTOL aircraft. I have aimed to construct an aircraft similiar in performance to the V-22 Osprey.

My aircraft has 4 engines, mounted to 4 separate pylons. It is designed to be extremely rugged and features extensive redundancy in it’s core systems. All of the static thrust and lift calculations are based on 3 engines, not 4, meaning the aircraft can sustain a complete failure in one engine, rotor, or rotor assembly without crashing. The V22, by contrast, can sustain an engine failure by routing power from the remaining engine through an interconnecting driveshaft, in order to power both rotors, however, it cannot withstand a single rotor failure , a failure in the driveshaft to either rotor, or extensive damage to either engine assembly.

Designing an aircraft of similiar weight to the V22 to run on three smaller rotors instead of two large ones proved to be more difficult that I thought, however. It seems that to make an aircraft like this work, I would need rotor blades that are much larger than I had originally planned (This is likely why the V22 uses such large rotors). With four engines mounted to the fueselage, and the wings mounted separately to the fueselage, the aircraft would have to be very long, and therefore, very heavy. I would also have to reenforce 3 separate parts of the aircraft (the wing mounting points, and the mounting points for both sets of engines) which would add weight and reduce the cargo carrying capacity. The V22, with its twin rotors mounted to the tips of the wings, only has to reenforce one point on the aircrafts body.

The preliminary specs of P151 are as follows:

Maximum Takeoff Weight: 27,500 Kgs
Minimuim Thrust Required from each Engine: 27500/3 = 9166.6 Kgs
Target Cruising Speed = 482.803 KPH, (300 MPH)

For Each Engine:
RPM: 650
Prop Diameter: 7.62 Meters
Prop Pitch: 0.2286 Meters
Thrust = 92,720.4 Newtons, (9454.84 Kgs)

As I previously stated, the prop diameter is going to make it very difficult to fit four props and two wings on this aircraft. The RPM is also very high, ideally, it wouldnt be higher than 500. The pitch is very low, I am not sure if this is a workable number for pitch. Other than that though, these numbers seem to be accurate. I think the concept at least, is feasible.

One other concern that I have just discovered is that since the rear engines are located directly behind the front engines, the disturbed air from the front engines may make them less efficient in airplane mode. I may need to move the rear engines to keep them in clean air.