One of the more time-consuming changes was to the landing gear retraction system. Recoiling from the snakes-nest of hydraulic piping under the seats of the first Melmoth, I had built this landing gear with all three struts mechanically connected and operated by a single hydraulic cylinder located six inches away from the hydraulic pump in the wing centersection. There are no up-locks; the retracting arms rotate to an overcenter position to hold the gears up. There are no sequencing valves; bellcranks and pushrods open and close the doors.
This arrangement works well in all respects but one: it has a poor mechanical advantage at the gear-down end of the cycle. This is not a problem for the mains, because they want to fall into place anyway. The nose strut, however, extends forward, against the wind. I knew well in advance that there would be a limit to the amount of aerodynamic resistance the system could overcome, but I satisfied myself, by calculation and by practical test (namely, placing a weighted cardboard box in front of the tire), that there was sufficient power to get the nosewheel down and locked.
As I described in February's Flying, the first time I retracted the gear in flight it would not lock back down. I tried again and again while Mike, flying chase in his Long-EZ, observed from below. After what seemed like an eternity of trying-it was probably less than five minutes-we hit upon the (in retrospect obvious) expedient of slowing to 80 knots and throttling back to idle, and the gear locked down.
Thereafter, this procedure became routine, but I never exactly enjoyed it. Once back at Whiteman, I installed both a gas spring and an additional hydraulic cylinder in the nosewheel well. The three struts are still mechanically linked to one another. I plumbed the new cylinder into the system by digging a trench in the foam-cored cabin floor and burying the lines in it-coincidentally at the same time as a new water main was being installed in a similar fashion under the street on which I live. The gear now operates normally, and even free-drops and locks at 100 kias, and the water pressure at home is better too.
Melmoth 2's many similarities to its precursor are partly due to their overlapping histories. But even if the second airplane hadn't begun life as a modification of the first, I would probably have designed it similarly. In most respects the first Melmoth had met my expectations, and there was little about it that I disliked. Besides, I don't have that much confidence in my abilities as a designer, and so I'm afraid to try anything too new.
The principal changes between Melmoths 1 and 2 are composite construction in place of aluminum; a tapered high-aspect-ratio (11.6) wing rather than a rectangular low-aspect-ratio (6) one; updraft cooling rather than downdraft; a fixed stabilizer rather than an all-flying stabilator; four seats rather than two; and a sidestick in place of a floor stick.
Less consequential changes include a belly- rather than wing-mounted speed brake, stouter main landing gear with 600 x 6 rather than 500 x 5 tires, and a single-slotted Fowler flap of larger area and smaller angular deflection (30 degrees versus 45) than the first airplane's double-slotted one.
Even though the differences between the two Melmoths are no more than evolutionary, Melmoth 2 is still a completely new design. The only components common to the two airplanes are the 200-hp turbocharged Continental TSIO-360-A engine, 76-inch Hartzell constant-speed propeller, hydraulic pump, instruments and avionics, and various bits of small hardware.
You would expect the new airplane, with half again the wingspan, to climb better, and it does; at 100 kias, with two people and 30 gallons of fuel aboard, it pegs the 2,000-fpm vertical speed indicator. It seems to be slightly faster than the first Melmoth in level flight, in spite of being larger; and I may still pick up one or two knots from nosewheel doors, flap track fairings, canopy seals and refinements to the engine cooling. My performance target was the same 200 knots or so at 17,000 feet, which means, most of the time, 175 ktas at 10,000, using around 10 gallons per hour. It does that now. It's less nimble than the first Melmoth, however, partly because the span is larger and the ailerons are relatively smaller, and partly because the stick forces in roll are higher than I would like.
Takeoff acceleration is very rapid. I rotate somewhere around 70-80 knots. Initial climb speed is around 100 knots, using 32 in. Hg and 2500 rpm. Approach speed is around 80-85 knots; I rely on a Safe Flight angle of attack indicator more than on the ASI to hold the approach attitude. The stall speed has not been measured since a properly calibrated static source was installed, but with the original static system it was 68 knots with power and 62 without.
People ask why I opted for the T-tail. The simplest answer, from among several equally plausible candidates, is that when I built the first Melmoth T-tails were in fashion and therefore, as fashionable things always do, they seemed a natural and superior choice. The sequence of events that led to Melmoth 1 having a T-tail was actually a bit more complicated than that-it started life with the stabilator on the fuselage-but once I had it I truly liked what it did for the airplane. In particular, it made for reliably smooth landings, which I attributed to the wing getting into ground effect before the stabilizer and producing a nice, effortless roundout. And so, if for no other reason than not to lose that quality, I stuck with the T-tail on the new design. It worked; Melmoth 2 lands in the same smooth and effortless way.
I abandoned the all-flying tail, however, for two reasons. First, I felt uneasy about the change in dynamic balance that occurred when ice collected on the leading edge. Second, I felt less confident about spreading its highly concentrated pivot loads into the composite structure than into the metal one.