Zoomzoooie
Well-Known Member
I have a one of kind 85% Cub project I am rebuilding and modifying. It's very similar to the N-3 Pup in construction with 4130 fuselage, but with all wood wings. I will be adding flaps and a wing folding system.
The plane originally flew with a Rotax 503, but I have 4 cylinder 4 stroke for it which is heavier. Lengthening the fuselage would balance out the added engine weight.
I was also thinking of adding a rear seat. The problem is the fuselage is narrow at 22.25" wide on the inside and is not very tall where the rear seat would go. That makes a very tight fit back there and would accomodate only smaller people and not leave much room for rudder pedals. Widening and lowering the fuselage would solve these problems.
The way I originally thought about widening was by cutting down the longitudinal center which would involve a lot of work and new diagonal tubes. I would be better off to make a new fuselage, so I put that idea on the back burner until a few days ago when I thought about it again. This time at a different angle with minimum work and minimum new tubing in mind and better than making a whole new fuselage.
Here's the idea without going to too much detail:
First cut the back end of the fuselage off where it lines up with the trailing edge of the wing. This section would be moved back 18"-19" and new tubing added.
Where the longeron lines would match up to the forward fuselage is the amount the fuselage would have to be widened and lowered to match back up.
Second, the front section of the fuselage would be cut down the longitudinal and approx 4" extensions added to the cross tubes to widen it.
Third, cut the lower section of the forward fuselage and lower it 2".
All diagonals would have to be cut out and replaced with new ones.
The new extensions would be welded in with insert tubes on each side and rosette welds. I expect the added weight to the airframe for this major major mod to be less than 10 pounds.
I don't think this has ever been done before so your thoughts and suggestions are welcome.
The plane originally flew with a Rotax 503, but I have 4 cylinder 4 stroke for it which is heavier. Lengthening the fuselage would balance out the added engine weight.
I was also thinking of adding a rear seat. The problem is the fuselage is narrow at 22.25" wide on the inside and is not very tall where the rear seat would go. That makes a very tight fit back there and would accomodate only smaller people and not leave much room for rudder pedals. Widening and lowering the fuselage would solve these problems.
The way I originally thought about widening was by cutting down the longitudinal center which would involve a lot of work and new diagonal tubes. I would be better off to make a new fuselage, so I put that idea on the back burner until a few days ago when I thought about it again. This time at a different angle with minimum work and minimum new tubing in mind and better than making a whole new fuselage.
Here's the idea without going to too much detail:
First cut the back end of the fuselage off where it lines up with the trailing edge of the wing. This section would be moved back 18"-19" and new tubing added.
Where the longeron lines would match up to the forward fuselage is the amount the fuselage would have to be widened and lowered to match back up.
Second, the front section of the fuselage would be cut down the longitudinal and approx 4" extensions added to the cross tubes to widen it.
Third, cut the lower section of the forward fuselage and lower it 2".
All diagonals would have to be cut out and replaced with new ones.
The new extensions would be welded in with insert tubes on each side and rosette welds. I expect the added weight to the airframe for this major major mod to be less than 10 pounds.
I don't think this has ever been done before so your thoughts and suggestions are welcome.
