Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
Oh yea, I remember that airplane, but can you really call it a true ducted fan?The old JM-2 pusher named "Pushy Galore" had a place perfect for a small ducted fan ... right at the propeller. I watched it race several times and it always accelerated away from Nemesis easily. Then Nemesis would slowly acclerate and about lap 2 - 3 would catch and easily pass Pushy Galore. I always thought the real problem for Pushy was the pitch of the propeller, not the design. But Bruce Bohannon never put a higher-pitch prop on Pushy and, soon after the last time I saw it race, it was donated to the EAA Museum (I think) and he started flying his Exxon Flying Tiger modification of a Van's aircraft.
However, the JM-2 was always described as being "not fun" to fly, so adding a heavy (relatively, compared with the prop) ducted fan at the stock prop location might not be possible, much less desirable. The Formula Ones were limited to a small Conteniental engine, and it might take a bit more power to get the same performance, much less more, from a ducted fan.
In the RC world, ducted fans take a high-horesepower engine that doesn't really produce a lot of thrust until the piston engine is screaming at very high rpm. I can't help thinking that the resulting gearbox, to GET to the high rpm, would add weight and complexity, the fan would be heavier than the propeller it is replacing, and the entire package might require more engine than the class allows.
I think they could allow a ducted fan class that would make good performance, but it would not be in the same class as any current class.
I might be wrong, but the added weight of a gearbox and the added weight of the fan unit would seem to take the new aircraft out of the Formula One specification. Just my speculation.
Oh yea, I remember that airplane, but can you really call it a true ducted fan?
Yeah but it works. I never said the venturi effect doesn't happen, radical up is to counter act the venturi effect and deflect the air down.Engguy, haven't you ever noticed the radical up angle a aircraft has to adopt to fly upside down ??
Engguy,
A rocket in space? The thrust comes from the pressure at the front of the combustion chamber. The low pressure is at the rear, where the opening lets the pressure escape. The thrust comes from the difference between the pressure in the front of the combustion chamber and the presure at the exhaust.
Good luck with your theories.