Kinebohのブログ一覧

Bench testing of two motors, OS 25LA and OS 32F with pressure nipples for YS fuel injection system proved the opinion by Mr. Yamada in Aichi Pref. was to the point, as a matter of fact, making the drum type lower throttle hole a bit opened in order to idle mixture richer was scientifically correct. The idling rotation is very stable without any symptoms of motor stop. Let's see what will happen if the motors were actually installed onto the airplanes.
I know that not a few users had thrown away the YS pressure injection system already because of unstable transition from idle to middle speed. Motor stop phenomena happens if the pressure regulator adjustment should be incomplete. I have often come across with such kind of situations, not a few airplanes were destroyed because of the system malfunction.

As for myself, I have ever been living with YS system as long as 20 years, so I have no hesitation to invite this one to my small airplane if the main needle reaction might be so peaky and troublesome to seek the best angular position.
The key to success and mastering this system is the adequate regulator angular position, there are several ways to know the terminal position to start and to adjust.
Remembering the past, this procedure to fix the regulator angular position resembles that of idle mixture screw in the fully mechanical old WEBER 40 DCOM carburetor for a sporty automobile, Talbot PEUGEOT 205 Rallye homologation model had that twin carburetors, had I been keeping it over ten years. And I would often visited in this 205 Rallye model Land Transportation Office for 2years continued regular inspection held by Authorities.

An application of additional shnyure port in OS 25LA cylinder brought several changes in combustion state, inviting powerful rotation 12,100 rpm with Graupner 9-5 prop under K&B 500 fuel taking along vigorous vibration, but is within tolerance. Apparent improvement of combustion efficiency was observed. In order to eliminate 3 dimensional vibration adequately, several trial experiments should be performed utilizing mechanical vibration tachometer gazing at trembling directions though the method might be so primitive now a days, re-balancing of the counter weight is performed like this even in the manufacturer's research and developing division.
Some lean mixture at idle speed of 25LA on the testing bench reminds me of the very important advice 30 years ago done by the former representative of Yamada Industrial Company at Inuyama City in Aichi Pref, the lower throat of the drum type throttle valve should be slightly opened because of lean mixture compared with the condition of natural aspiration carburetor, YS regulator controls only at middle speed and the slow speed mixture should be established promptly. In another words, very accurate and perfect balance of the drum throats upper and lower throat comparison could eliminate complicated mixture control and adjusting at idle speed in the carburetor construction. Careful checking on this important point, the fact was revealed that all of the genuine YS motors has throttle valves so designed as he had said to me.
Though I do not know he is now alive or not, hope I he is still now in our world, because we have a lot of fond memories. Now, the company has been finished the change of generations, his sun is inheriting the company.
Anyway, the bench test of modified carburetor in 25LA would be performed fairly after such modification on the throttle valves, I'm sure that the experiment would obtain favorable result.
By the way, the main needle valve for natural aspiration design makes it difficult to control and adjust precisely, dull angled needle shape makes it too sensitive and too keen to adjust it in NA fuel supply condition, only one click changes the mixture ratio effusively, but it is not impossible, within my tolerance at all.
Once obsessed by the attractive interests and curiosity of the internal combustion motors, it is very difficult for me to withdrawal from it.

Too low temperature outside invited several problems for Rooky10's flight early in the morning yesterday. As a matter of fact, it was obliged inevitable emergency landing not on the run way but on the vegetable garden near by, the damage at that time was not so much as imagined. Plowed soft soil must have reduced the damage, in addition, the weight of Rooky10 is below 1kg. 2 degree below zero celsius affected on atomization of fuel alcohol and the activity of batteries for both Tx and Rx resulting motor stop and loosing control from 100m distance. I knew after that a digital camera cannot work around 2 degree because of the physical property of Nickel-hydrogen battery. A plane crash has never been experience for these 30 years, I fee like myself a beginning layman in this field if I fly a trainer airplane?

As a revenge of this accident, I made up my mind to make a Shnurle scavenge port that lack in 25LA cylinder. Brass material of the cylinder made it relatively easy to engrave additional port on the adequate portion and much more efforts were required to engrave it's gas way in the crank case inside. Opening timing of newly prepared Shnurle port was the same as existing side ports. Test running would be performed soon.

From the beginｎing I have been setting my heart on the performance of the old VW air-cooled 1600cc Boxer motor does not run at higher rotation because of OHV design that might invite some hesitation to gain higher rotation, but an improvement on ignition constructive design just applying semiconductor in the in the primary coil circuitry proved my selfish consideration was completely out of focus. The transient property to higher rotation is comfortable enough to satisfy myself! In another words, the character of my VW1302 Super Beetle has completely changed from dull and lazy boy into a young crisp Parisian, how come?
On the other hand, an energetic motor transformed by newly invited semiconductors in the ignition system revealed some lack of potential in the axle constructive design that has too movable and soft rubber bushes. Anyway, the principle that the total balance is indispensable at all, any reinforcement on one part in the vehicle design causes some destruction of the originally designed total balance, realized I again this fact last night.

Fully mechanical Vocar 34PICT3 carburetor in VW1302 Super Beetle was readjusted following to the principle of it's designer, both bypass screw 2and 1/2 turn counter clockwise and air volume control screw also 2 and 1/2 turn to the same direction. Stable throttle actions were obtained after the work this morning. I have realized again the importance of setting the reference angular positions prior to the starting, any guesswork that needs precise adjustment could not bring good results, we should respect and admire the intent of the designer of this carburetor. Improvement of the combustion due to applying Semi-Transistor ignition system taught me how I did it imperfectly for these 3 years as a matter of fact. Probably, unfavorable fuel consumption would be improved also.
I have 2 another carburetors for Beetle as spear part, 2 distributors and 2 ignition coils. I lack spear one of mechanical fuel pump? I must prepare it sooner or later, because the fracture of diaphragm rubber means critical stuck.

The inner door handle destroyed by my mistake was repaired thoroughly by adhering the portion utilizing the material, Autopolymerizing Acrylic Resin as a additional reinforcement structure. Though, I hated the using quality with old sense of really old half broken automobile because of hanging out handle, all the bad habit disappeared after that except the inconvenience of right rear door lock actuator pin fracture. All the machinery should be continued with love on it and with some admiration to the machinery designers, because all of them exerted desperate efforts to design serving our field with good operations intentionally.

20 years long used Digital Multi Tester was disassembled and maintained on the sliding contacts inside. LR44 cell batteries also replaced into new ones, original performances could be re-obtained again after that. Development of tools and devices are also an important task for craftman in the world.