Alan Littlewood Dear Carlos, Here are some of my observations which you may want to print. I built MONI number 248 in about 1250 hours, over a two year nine month period and wrote an article which appeared in about the last issue of MONINK before INAV went out of business. Since that time, about 15 months, I have flown seventy-eight hours in my MONI. Reading your first newsletter was very interesting and it is clear that there are some common problems or characteristics about the aircraft. Firstly, I too have gone through two spinners, both of which failed exactly as you described, after almost exactly twenty hours. I was most upset because I spent twenty five hours making the second one, getting it properly balanced, shaped and very smooth cut-outs. It seems obvious to me that the soft aluminum just cannot withstand the stresses on it from the KFM 107 engine speeds. I have not done it yet, but plan to make a spinner of Fiberglass, to see if that would be suitable. Do any readers have any knowledge, experience or learned opinions on this idea? I became friends with Jim Ferguson in Santa Clara through building the MONI. He preceded me by about eight months through the whole project and now we fly together in formation wherever we go and have a lot of fun at it. Jim didn't bother replacing his spinner after losing the first one and we both are presently flying without them. Jim has had two experiences of the propeller attachment bolts shearing off and I have had it occur once. It occurred to me on the flight I made to San Louis Obispo to visit John Shaw. While I was in the process of back-sawing off the thread to remove the nut at the back which gets trapped between the propeller flange and the alternator casing, a gentleman came up to see what was going on. He claimed to have spent many years working with wooden propellers and said you MUST torque the bolts frequently. As temperature and especially the humidity changes, the wooden prop will swell and contract and change the tension on the bolts. This makes sense to me, so on preflight checks I make a point of checking the 4 propeller bolts and nuts and re-torque them every few flights to 144 INCH POUNDS. I still have my original prop which came in the kit and hope it will last. Jim Ferguson has had about 3 new propellers and none of them seem to perform as well as mine. Does anybody know where Monnett got his props from and/or the characteristics of this design? My MONI has the 22 HP KFM 107E engine and I'm not very good at tuning it. Judging by your first publication, I'm not the only one. At the moment I get 5200 RPM at take off and this produces an acceptable performance. I have not made any careful measurements but get about 400 FPM climb for the first couple of thousand feet. Now sometimes, not always, I get a problem when I go above 6000 feet. If the throttle is wide open, it runs OK. but if I throttle back to cruise at about 5500 RPM, then after about 8 seconds, the RPM drops down to a much lower value for about 3 seconds and then picks up again to the cruise setting. I can sit there and not do anything and this cycle will repeat indefinitely. I can tell you I am not very comfortable while this is going on, as it's usually over the mountains surrounding San Jose and to do something, like lose height, to make it go away. I have made carburetor adjustments but the problem is still there "sometimes". Reading your first articles about a fuel pump, I am wondering if this is what I need. Does anyone have any ideas? What fuel pumps are available and is any one recommended? The Mikuni carburetor is fitted to my engine. From what I read, it is clear there have been changes in the carb. Can anybody write a history of the changes, why they were and the advantage, if any? My canopy latch is exactly as shown in the plans. I make sure the canopy is shut securely before take-off and there has never been any hint that it would come open in flight. This has happened to several people though, so I would like to know how. Does it unlatch itself, or is it being accidentally knocked, perhaps when operating the brake lever? Has anybody designed a better trim arrangement? The original design could certainly be improved upon. Best Regards, Alan Littlewood Editor's response: Thanks for the letter Alan. Please seeRon Fisher's letter in this issue for his input on how to make a fiberglass spinner. I also fly with the Mikuni carburetor with an additional Mikuni fuel pump; but I've converted my KFM to 30hp. I find that I have 3 power settings; full, cruise and none. At cruise there's a range around 5200rpm were my engine doesn't surge or drop as long as my IAS is 80mph or higher. Since you have all those high mountains to contend with, have you considered adding a mixture control? The rpm drop is probably due to an excesively rich mixture. An EGT gauge is essential in knowing what the mixture is doing. The only change that I am aware of to the Mikuni carb was to make it a BMR (Better Mid-Range) by the addition of "a new power jet as well as improved diaphragm system". Mine had a yellow stripe painted on it after the mod. On the open canopy question, I don't believe that people are accidentally knocking them open. The whole latch arrangement doesn't really provide a good positive lock mechanism.
"Live long and fly safe ..."
_