Radio Control: Helicopters
THIS COLUMN will not be what I had promised. The past month has been a very hectic one, and I have not been able to complete testing the tail-rotor mix set-up. I have it working but not to my satisfaction. So rather than confuse you, I'll do some more testing and then fill you in. There are a couple of things in last month's column that I did not make too clear. First of all, I did not include a drawing of the collective cam. For those of you that have been following these articles to set up your machine, I apologize for this delay. The size of this cam will depend on the throw of your servo. I would suggest, at this point, that you select the fastest, smoothest, and most powerful servo for the collective position. This servo must drive the carburetor and the collective bellcrank, and all of the other mechanics that go to the head.
Radio Control: Helicopters
EVEN THOUGH the helicopter rules have been voted in and will be in the 1978-79 Rule Book printing, the event itself will not be part of the regular Nationals until later. Because of this and the fact that a large portion of RC helicopter activity is in the eastern part of the country, it has been decided to hold the 1977 Helicopter Nationals in South Bend, Indiana, on June 10, 11 and 12. They will be held for those three days at the Tri-Valley RC field, 14154 Cleveland Road, South Bend, Indiana. The events will be Novice, Intermediate, Expert, and Scale with awards through three places plus Best Scratch-Built helicopter. The reason for adding the third day is that we are expecting a large entry, and it will permit us to run it at a more leisurely pace.
Radio Control: Helicopters
HELI-BABY Tail-Rotor-Drive Mod: When the Heli-Baby was first developed, the trail-rotor drive was accomplished through a V-belt drive that did not require much tension. However, in use this belt proved to be inadequate and was changed to the flat belt, which required a substantial tension. This tension caused a great deal of wear to the tail-rotor shaft running in needle bearings. It also caused wear to the clutch-gear shaft and clutch-needle bearing. The 1976 series Heli-Baby has an improved clutch bearing and has tail-rotor ball bearings that greatly improve the wear factor. However, the clutch-gear shaft is still supported by one ball bearing, and belt tension produces considerable drag that robs power to the head. I have made several suggestions to the powers that be to correct this problem with nothing being done, so I decided to do it myself!
Radio Control: Helicopters
SINCE MY LAST column, I have been doing a lot of testing of the tail-rotor mix for the Super-Baby. Along with my efforts, I have had the help of some interested parties so the testing has been done from several points of view and on several types of helicopters. This mix, properly set up, will work all the way from idle to full collective and is totally linear. The first thing to do is to determine the value of your tail-rotor servo pot. You can do this by asking the manufacturer or by measuring it with an ohm meter. While the servo is open, solder a wire to each terminal on the pot-red and black for the outer ones and white for the center. Run these to a female plug and then take the male side of the plug and make wire ends to match the other plug. These ends should be about 5 inches long.
Radio Control: Helicopters
THE MRC SCHLUTER Super-Baby arrived on the market before the #761 conversion-collective kit that can be fitted to any Heli-Baby. In fact, it can be fitted to any .40-size helicopter. They are now available from your favorite dealer or direct from MRC, Edison, N.J. Upon examining the Super-Baby kit, the helicopter has not been changed at all-just the head and related collective parts. I took the head package out first and laid out all the parts in separate trays. All related bolts were in one tray and lock nuts in another, flat nuts in another, and so on. In this way things are much easier to identify, and you can tell if anything is missing. With it all laid out, I read the assembly manual.
