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OS rear exhaust 60 motor RF was disassembled thoroughly and the crankshaft supporting main bearings were replaced into new ones, R6Z for front and 6903 for rear promptly. Clogged and rusted piston pin prevented me from removing the connective rod from the crank pin, because some smooth axial movement between connective rod small end and piston pin was lost, rust was the criminal. Chronic slipping result was observed on the crankshaft as shinny mark on the rear bearing inner surface portion, the damage was not so critical, so it's reusable was my decision.

This OS 61 RF motor has not experienced breaking in and running in procedure, shinny spot on the piston vertical surface was removed with my best concentration and care. Because the carburetor fitted on was for the use under fuel mechanical pressure condition 86 butterfly throttle type, it was replaced into 7D carburetor with 8 mm diameter throat venturi. I prefer natural aspiration conditioned combustion to any fuel pressured circumstance caused by mechanical diaphragm pump, but YS regulator system is the only exception. According to my past experiences over 30 years ago, the diaphragm cannot follow the pulsing signal over 12,000 rpm, no matter how any diaphragm thin material might be invited, this phenomenon was observed even on an original Perry pomp system, so a diaphragm pump system should be used only the operation condition just under 8,000 rpm which means that suitable for four cycle motor?

In spite of my good intention to participate in the meeting "Old Timer & Golden Age" being held on 9th April this Spring would be postponed. It's a matter for regret for the precious meeting to be put in future indefinitely. Not a few old modeler all over our country feel it sad to know about that.
The reason was a fire broke out the other day there, some professional firemen come and it took them as long as 3 hours to put under control it, not a small area covered with reed was worn away by this accident.
Rotating wing model airplane fell down and it caused fire, probably an electric powered one and it's Lithium Polymer battery exploded, so I guess.
As the worst result, Kyoto Uji flying place might be closed, basically it is situated in relatively dangerous Uji River bed, because, a high way was built near by it few years ago. I checked by running on the high way actually, how near the flying place situates and how dangerous it would be if any model airplane might fall down on the high way hitting some car by accident.
So, I never fly my model airplane there and just bring & show my friends my new constructions.
Consequently, the next planning for "Old Timer & Golden Age" by KMA is not decided, we don't know where and when, but we will meet again some sunny day.

A fuselage of "PILOT Junior" is now under construction, side plate thickness is changed from 3mm to 2mm, because of too much stout original designing leading to weight increase. L.m. Cox Medallion 15 modified into throttle valve model by creating the carburetor holder would be invited as the power source of this 50 years small airplane. Relatively low combustion pressure would make it possible that operation performance is not peaky but stable and controllable one. Though have I some Tee Dee models, The performance and attitude are not inspected yet when the throttle valve is set in position, so , I'm looking forward to examine about this point. To tell the truth, I have never seen that Cox motors are used in good operating condition for over 50 years, this is one of the reason that I made up my mind to make up by myself a carburetor holder on the Cox motors, for both 15 and 09.
Smaller shoulder wing type model airplanes that I have not try yet are"Hinode Skybeam by F. Arigaya" and "Picnic Junior " by S. Itani. I'm going to proceed to them very soon, just interesting, aren't they?

Carburetor holder modified L.M.Cox Medallions have been completed adopting with ENYA carbs. I'm not fond of needle valve equipped in TV carb because of it's stout construction with heavier weight. Unnecessarily too much weight would cause various problems especially in the actual combustion circumstance, destructive vibration produced by inevitable crank shaft knocking while operation might cause resonance vibration.
On the other hand, my way just applying 2 mm diameter screw with the tip shaped on the potion of the fuel measuring point, because the purpose of needle valve is to measure the amount of fuel flow and fix it to keep the stable motor operation.
The critical part of the purpose is just only the shaped and tapered needle tip, the thumb knob has nothing to do with it. In addition, the suitable needle position does not always change so often so far as we supply 15% Nitro-Methane including fuel.
Consequently, the needle valve set on OS 40 D carburetor directly on fuel supply nipple potion does a part of the purpose enough.I would continue this method for the time being especially checking on the durability.

A single channel controlling "PILOT Junior" is my next planning to proceed. Fuselage plates and stabilizers, vertical and horizontal ones are already prepared. I'm going to choose K&B 15 old motor, adapting ENYA throttle valve and OS 701 silencer applying some modification. This model would appear not in next meeting but in the coming Autumn one. Anyway, I'm looking forward to the meeting held on 9th April this year, because my lovely PILOT Ace B is standing by under fully fine condition. I can meet with intimate old friends there and enjoy precious time each other.