rrudytoo

My Feedback: (27)

Hello All,

I just acquired a Duellist 2/40 and I don't know which Mark it is. The plans are dated 1990 and is Pica kit # RC-5. I don't see anything that specifically says "Mark II" so I'm thinking I have an earlier version.

If this is the case, what am I up against? What was changed between the two versions?

Thanks, in advance.

Al

William Robison

My Feedback: (3)

Al:

All the Pica kits were the "Mark I" version, but they were never given a mark number, either by Dave Platt (the true designer in spite of Morton Tanger's name on the plan) or by Pica.

The original version was first kitted by "Dave Platt Models," shortly after DP left the company which later became Pica, he revised the design and the revision was officially labeled as the "Duellist 2/40 Mark II."

If you place an example of each version side by side, the only real visible difference is the vertical fin and rudder. Internally the Mk II has two more ribs in the wing, and slightly more area. The Mk I has the wing and stabilizer at +2 degrees incidence, and five degrees down thrust in the engines. The Mk II has 0-0-0 on the surfaces and thrust lines.

The Mk I is the easier flying plane, better for the first time twin flier unless he's a pretty good aerobatic flier. The changes in the Mk II make it the better aerobat, it's more neutral in its stability with everything set at zero. The vertical fin and rudder were changes to decrease the roll coupling of the rudder in knife edge flight.

You can build the Mk I almost to Mk II spec, you wont have the modified wing but the empennage is easily done. When you build set the wing and stab to zero incidence, and eliminate the down angle of the firewalls, just glue them in straight.

Or you can glue the firewalls in straight and leave the incidences alone. This is sort of a 1/2 way measure, it will give you two degrees of up thrust when measured against the fuselage center line. Since the wing and stab also have the +2 degrees, with the engines matching, the effect is having the fuselage pointed down two degrees and everything else at 0-0-0 angles.

Pictures attached are the Mk I and Mk II v-fin and rudder drawings.

Bill.

rrudytoo

My Feedback: (27)

Bill,

I knew there was a story behind this and you've spelled it out perfectly. I will print out your reply and keep it handy for when the build begins.

Thank you!

Al

DamonTX

Bill,
Thanks so much for the explanation. I've been wondering why some have the flared tail and others don't. I like the flared one!

William Robison

My Feedback: (3)

Damon:

You're in luck. The flared tail, with the ventral fin and lowered rudder, is the Mk II, the more aerobatic version.

The Duellist 2/60 Mk II also has the ventral fin.

Bill.