If you were in the market for a 50hp engine for a small 2 seat ultralight type aircraft, why would you pick a Rotax 503 over Valley Engineering's Big Bad Twin?
From what I can tell looking at available info online, they weigh very close to the same and put out very similar power. But then that's where the similarities end.
The 503 gulps gas like it owns it's own oil refinery, can be finicky to tune properly, is very dependent on stable EGTs, and needs to be decarboned and then overhauled at fairly regular intervals.
The Big Bad Twin burns less than half the gas, is apparently very reliable, requires only oil and spark plug changes for maintenance, and some folks are talking about 3000 hour TBOs. (probably a bit optimistic but the TBO will DEFINITELY be longer than the 503s 300 hrs)
Am I missing something? Why haven't we all ditched our 503s in favor of the BBT?
From what I can tell looking at available info online, they weigh very close to the same and put out very similar power. But then that's where the similarities end.
The 503 gulps gas like it owns it's own oil refinery, can be finicky to tune properly, is very dependent on stable EGTs, and needs to be decarboned and then overhauled at fairly regular intervals.
The Big Bad Twin burns less than half the gas, is apparently very reliable, requires only oil and spark plug changes for maintenance, and some folks are talking about 3000 hour TBOs. (probably a bit optimistic but the TBO will DEFINITELY be longer than the 503s 300 hrs)
Am I missing something? Why haven't we all ditched our 503s in favor of the BBT?
