Duellist down thrust.
02-26-2004 | 09:28 PM
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From: Bristol, TN
Duellist down thrust.
Does anyone know why the Pica Duellist has down thrust?
Is this stock amount of down thrust needed?
Also, does anyone know where the thrust line on the firewall should be?
There does not seem to be any left or right thrust, just down thrust, is this correct?
Does anyone have better thrust settings than Pica?
Is this stock amount of down thrust needed?
Also, does anyone know where the thrust line on the firewall should be?
There does not seem to be any left or right thrust, just down thrust, is this correct?
Does anyone have better thrust settings than Pica?
02-26-2004 | 11:44 PM
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From: Mary Esther, Florida, FL
RE: Duellist down thrust.
CC:
Dave Platt's original design of the Duellist, which is still being kitted by Pica (even though the design is no longer credited to him) has two degrees positive incidence on the wing and horizontal stabilizer. The firewalls were set at five degrees downthrust in the nacelles, taking away the plus two degrees on the wing, the net downthrust was three degrees. And there was no side thrust in either engine.
These angles were the result of Dave Platt's early experiments with twin engines, and made the airplane easier to handle in [i[upright[/i] flight, and minimum trim change with differing power settings.
While the original rigging made a good upright flier, it had the opposite effect on inverted flight.
About two years after putting the Duellist kit on the market from Dave Platt Models, he did a redesign and published the Duellist 2/40 Mk II version. This was just about the time Dave Platt Models had a management change, and became Pica. The result was the Mk II version was kitted privately only, and only for a few months. DP had planned to produce a 60 sized Duellist about that same time,but it was built as a prototype only, and only one was made, according to what Dave told me. The Duellist 2/60 Mk II was in production last year about this time, currently not available, but I hope it will again be on the market again later this year.
The Duellist 2/40 Mark II is very similar to the Mark I, the visual difference is the rudder having no balance area, and it extends below the fuselage with a sub fin to fair the lower portion. The structural difference is two more rib bays in the wing with a slightly increased span, and a built-up empennage instead of the solid construction of the tail fins on the Mark I. The big difference is aerodynamic. The Mk II wing and stab are installed at zero incidence, and the downthrust of the engines is eliminated. The Mark II is rigged a 0-0-0 all the way. The 2/60 Mk II isw also a zero angled airplane.
By lowering the rudder's center of aerodynamic pressure the KE flight is a lot nicer, and by going to 0-0-0 the inverted and upright flight characteristics are almost identical.
The Duellist 2/40 Mk I can be easily built with all the angles at zero, and this gives the earlier Mark I design the handling of the Mark II.
If you are a fairly low time pilot, still getting yourself in trouble every now and then, build the Mk I with stock angles, they make it a better trainer. Otherwise do the modifications, they are well worth while for the advanced flier.
Questions I've not covered? Please ask.
Bill.
Dave Platt's original design of the Duellist, which is still being kitted by Pica (even though the design is no longer credited to him) has two degrees positive incidence on the wing and horizontal stabilizer. The firewalls were set at five degrees downthrust in the nacelles, taking away the plus two degrees on the wing, the net downthrust was three degrees. And there was no side thrust in either engine.
These angles were the result of Dave Platt's early experiments with twin engines, and made the airplane easier to handle in [i[upright[/i] flight, and minimum trim change with differing power settings.
While the original rigging made a good upright flier, it had the opposite effect on inverted flight.
About two years after putting the Duellist kit on the market from Dave Platt Models, he did a redesign and published the Duellist 2/40 Mk II version. This was just about the time Dave Platt Models had a management change, and became Pica. The result was the Mk II version was kitted privately only, and only for a few months. DP had planned to produce a 60 sized Duellist about that same time,but it was built as a prototype only, and only one was made, according to what Dave told me. The Duellist 2/60 Mk II was in production last year about this time, currently not available, but I hope it will again be on the market again later this year.
The Duellist 2/40 Mark II is very similar to the Mark I, the visual difference is the rudder having no balance area, and it extends below the fuselage with a sub fin to fair the lower portion. The structural difference is two more rib bays in the wing with a slightly increased span, and a built-up empennage instead of the solid construction of the tail fins on the Mark I. The big difference is aerodynamic. The Mk II wing and stab are installed at zero incidence, and the downthrust of the engines is eliminated. The Mark II is rigged a 0-0-0 all the way. The 2/60 Mk II isw also a zero angled airplane.
By lowering the rudder's center of aerodynamic pressure the KE flight is a lot nicer, and by going to 0-0-0 the inverted and upright flight characteristics are almost identical.
The Duellist 2/40 Mk I can be easily built with all the angles at zero, and this gives the earlier Mark I design the handling of the Mark II.
If you are a fairly low time pilot, still getting yourself in trouble every now and then, build the Mk I with stock angles, they make it a better trainer. Otherwise do the modifications, they are well worth while for the advanced flier.
Questions I've not covered? Please ask.
Bill.
02-26-2004 | 11:51 PM
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From: Mary Esther, Florida, FL
RE: Duellist down thrust.
CC:
Just looked at your post again. Engine thrust line is set on the firewalls in whatever position allows the nacelle to fair into the spinner. So long as both nacelles are set up the same it's not critical.
And if you have the majority of the construction done you can wedge the engines up to zero down thrust in relation to the wing, and you have effectively changed all the angles to 0-0-0, but you will have the fuselage at two degrees negative. But you'll never notice it, and you will have a great improvement in the aerobatic capability.
And yes, Dave Platt has a better idea on the angles than Pica. In spite of the credit on the plan Pica supplies the plane is Dave Platt's design, and he has made improvements that Pica has yet to incorporate.
Bill.
Just looked at your post again. Engine thrust line is set on the firewalls in whatever position allows the nacelle to fair into the spinner. So long as both nacelles are set up the same it's not critical.
And if you have the majority of the construction done you can wedge the engines up to zero down thrust in relation to the wing, and you have effectively changed all the angles to 0-0-0, but you will have the fuselage at two degrees negative. But you'll never notice it, and you will have a great improvement in the aerobatic capability.
And yes, Dave Platt has a better idea on the angles than Pica. In spite of the credit on the plan Pica supplies the plane is Dave Platt's design, and he has made improvements that Pica has yet to incorporate.
Bill.
