Do the new Monarchs have a bottom V-tail mount?

I heard the new Monarch's have a new bottom V-tail mount. Is this correct? If so, what is the reasoning for changing this from the original top mount.

Yes, after wearing out not just quite a few molds, but also the plug they were made from, we decided to make some changes in the new plug. The new fuselage for the Monarch 'D' series and the Wizard has a "closed" wing saddle (the top of the wing saddle is covered with fiberglass), and a closed tail saddle as well. The new tail saddle is designed so that the end of the tail boom mounts on the upper surface of the tail panels, nestled in the notch of the "vee".

The new closed saddle design stiffens and strengthens both areas considerably, which allows us to reduce the amount of glass in those areas. Overall the new fuselage is about .25 ounces lighter than the old one. The new shape also eliminates the need for the wing trailing edge fairing, resulting in less weight, less work for the builder, and one less part for us to manufacture.

There are additional advantages for the tail. The extra stiffness and dimensional stability makes the molded-in incidence setting much more precise and repeatable, and makes a removeable tail design much easier and practical. Just put a piece of plywood with some tapped holes in the inside of the tailboom end, then run two small nylon screws through the bottom of the tail assembly and up into the tapped holes. You could also probably get away with simply taping the tail on for initial flight tests, allowing you to experiment with different shims to adjust the incidence before locking in the final setting (not necessary, the factory setting works just fine, but I know some folks like to experiment with that).

Aerodynamically, the new arrangement acts like a fillet, smoothing out the airflow around the notch between the tail panels.

As far as disadvantages, there aren't any of real significance. It does mean that the pushrods are now pushing for down elevator, which theoretically could result in pushrod buckling during that hard down elevator push at the top of launch, one of the biggest control inputs in a typical HLG. In actual practice this has NOT been a problem. Probably the biggest issue is that it's now much more difficult to build a Monarch with a conventional tail, but we've found that very few folks want that option. By the time folks are investing in a high-performance model like this, they generally have a radio that can handle V-tails.

The Speed 400 electric Monarch 'E' and Wizard 'E' still use their original molds, so they still have the open wing and tail saddles. The open wing saddle is probably necessary for access to the battery compartment. Whether or not we decide to re-tool with a closed tail saddle will depend on market demand.

Don Stackhouse @ DJ Aerotech
djarotec@bright.net
http://www.bright.net/~djwerks/