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I really enjoyed building the TopCap. Why? I love truss style structures. Call me a masochist, but I love sanding/cutting all the miters, and I love the way a truss built structure looks. And for me, a truss lover, the TopCap was a delight. The entire fuse, as well as the tail surfaces, are built truss style, with plenty of miters to go around. If you don't like to sand miters, building the TopCap won't be a particularly pleasurable experience. The wing is a pretty conventional D tube, except for the use of a straight airfoil section aft of the spar. This allows you to build the symmetrical wing flat on a table without the typical alignment tabs. I've heard mixed reviews of this type of airfoil's flight characteristics. In comparison, a typical NACA style symmetrical airfoil will enhance the roll rate and defer the stall. However, the plane is designed to fly in a stall, and this type of airfoil seems to stall cleaner with less turbulence than other designs. After flying the TopCap, I have no problem whatsoever with its wing design.
Building went pretty quickly, and after a few weeks, it was time to install the radio. I placed the servos as shown on the plans, with the exception of moving the (micro) throttle servo to the opposite side between the aileron and elevator servos. The throttle cable guide goes through the center rib, then out the leading edge near the right side of the fuse. The allowed me to install the throttle cable inside the wing without a conflict with the fuel tank. The plans and instructions do not detail the installation of battery and receiver, and it is left to the builder to improvise. Most of the kits I have seen have the the radio stuffed in the wing LE along with foam. I chose to make a partial rib out of lite ply, extending from the spar to the LE, that fit halfway between ribs one and two. I then mounted the receiver and battery to this partial rib using zip ties, with foam to isolate them from vibration. This assembly was then glued in place in the front of the wing. This may have been more work than necessary, but I feel that it gave a neater, lighter installation.
This kit uses a pull-pull system for elevator and rudder. Some people complain about this, too, but I found it quick and easy to set up. Read the instructions carefully before beginning and you should have no problem. The pull-pull setup is well worth it in the end, as it is very neat looking and extremely solid.
Aerodynamically and structurally, the TopCap is one of the best designed kits on the market. Its design is one of a very few that I have felt needed no modifications for my style of flying. It is very lightweight without being fragile, and isn't overdesigned for the abuse of someone who chose a plane that was a bit over their head. It is rare that you find a model that, out of the box, is designed so well for the more experienced modeler, who really demands a lot of an airframe.
Having checked over the plane thoroughly, it was time to see how it would fly. This is one of those kits that you know will fly well, right off the board. There were no first flight jitters, as I anticipated no difficulty in getting the plane off the ground and back again. I wasn't disappointed. The YS45 had plenty of power to haul the plane vertical forever, and it was stable all around, and reasonably neutral with the CG at the center of the range. The power was a mixed blessing, however, as the throttle response of the engine near hover gives violent yaw and roll when dancing on the power. Smoothness is the key, and one day, I'm sure I'll soften up the throttle response curve near the hover point. On the plus side, the plane accelerates out of a hover in a way that makes the rocketry guys jealous. There's still not a plane at my field that comes close to matching it.
The long fuse and large tail surfaces offer plenty of authority for tight maneuvers. Knife edge is done at quarter stick, and knife edge loops are easily done with full power and three-quarter stick. Very little mixing is necessary to get rid of knife edge coupling, in fact, I have almost as much mix for throttle->aileron to counteract roll from the torque of the engine. The plane flies very well in a stall, and it is easy to fly in level flight with the nose pointed 60-70 degrees up (descending in this mode isn't so easy). Its flight characteristics make it the perfect plane for an experienced pilot to throw around, yet it is easy enough to fly for a third plane. I enjoy its versaility most of all, as it can be used to practice pattern (its hard to fly smoothly), it can be tossed around as a funfly, or can do a limited 3d routine. For this reason, it sees more flight time than any of my other planes.
You might note that I'm careful not to say that this is the ultimate in flying machines. Its not. If you want to do TOC style maneuvers, the TopCap is often TOO light and stable to perform them. The tapered wing and light stick built fuse keep the rotational inertia down, and this makes the plane rely almost exclusively on control inputs for tumbles. When the controls are neutralized, the plane simply stops spinning. This is great for funfly, but for 3d style aerobatics, its often not a particularly desirable trait. The plane was not designed for all out 3d, but just in case you thought it was, I will assure you that there are better choices for that style of flying, namely one of the larger scale aerobats. It also is not a particularly good hoverer, due to the large fuse. If you allow it to get moving sideways much at all in a hover, it will quickly right itself. It takes full attention in a hover, unlike planes such as the Sig Fazer, which basically hover themselves. These limitations are not oversights on the part of the designer, however. The plane was designed for funfly, and it excels at it.
Originally, this plane had a YS45 with a tuned pipe for power. Although this gave ballistic climbouts and was really impressive, it really made precision hovering and throttle control difficult. When a YS 53 4-stroke became available for this plane, I installed it, sacrificing power for smoothness. The plane will still hover at half throttle, but it has become much easier to maintain hovers and torque rolls. The YS 45 will find a new home in a faster plane not meant for hovering.
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