Gear in the Headlights

The long pause in my postings is due to an unusually heavy workload at Compositex... (what is this "recession" people keep talking about?) I'm not ready for retirement, and the incredible shrinking 401K does not help matters. But I can't complain.. the only thing worse than working is NOT working. Anyway, I will hopefully be less busy with the "day job" so I can devote more time to the Mosi project by the end of May.

I've been going back & forth on my landing gear choices, and this decision impacts the planned Y-tail and engine modifications. I've been stuck on this indecision loop for too long already, and am itching to move ahead. Here's some background on it:

The original Moni monowheel gear (one fixed main wheel near CG, two fixed wingtip wheels, one steerable tailwheel) is OK for the small 33" prop, but I need more ground clearance for the 40" prop, and a taller monowheel leg would drive the need for taller tailwheel and tipwheel legs too... it gets a bit ugly. The monowheel Moni ground handling and tipping forward/prop striking tendency has never received rave reviews from pilots to begin with, and putting it on stilts is bound to make it even worse. My plan for the last few months had been to convert it to a taildragger configuration (fixed dual main wheels ahead of CG with steerable tailwheel), which I still think is the coolest looking and simplest option... but there are drawbacks. Taildragger cons as I see them:

• Higher likelihood of prop strike
• Greater difficulty on ground handling
• Greater tendency to "ground loop"
  
• Less visibility of runway on takeoff roll
  
• Longer takeoff roll
• Greater difficulty with takeoffs & landings in cross winds
• Higher likelihood of damage to tail surfaces from runway rocks
• "Ballooning" back up after initial landing touchdown
  

So, I'm now leaning towards conventional trigear (dual mains behind CG with nosewheel). The original Moni had trigear as an option, but I haven't found much info. on this yet. Final decisions are yet to be made on brakes, steering and gear leg structure. Solid aluminum spring gear legs mounted on the fuselage is one possible answer, but this is a bit heavy and draggy and requires "gun drilling" to get the brake lines through. A streamlined hollow-molded composite spring gear of equivalent strength is certainly a viable option, and is probably what I'll end up doing. Another option is spring loaded gear legs mounted off the main wing spar and not attached to the fuselage at all. This would create less drag due to a smaller exposed frontal area and being located completely out of the propwash, but this option requires tearing into the wing skin. If I was building the wings from scratch, I'd probably do it that way, but I'm not.. so I won't. Even better would be retractable gear... but that's opening an even messier can of worms.

I'm thinking a steerable nosewheel with symmetrical main wheel braking is a much better option than castoring nosewheel and differential braking of main wheels, mostly because of how the brakes need to be adjusted and controlled. Direct coupled nosewheel steering needs to be designed at some rudder-to-wheel steering ratio TBD.. I need to learn more about that to do it right. In any case, changing to trigear on the Mosi increases the labor hours even more, but I think the result will be better overall. -- Change one thing, change EVERYTHING!!

As always, your comments are welcomed.