HINTS AND TIPS

The Buttons below will take you through the different hints and tips that I feel will make your helicopter safer and more reliable.

   
         

Control Movements and Stops

Ease of control movement

Controls should be smooth and not tight in all directions of intended travel.


If any control seems tight then find the area of excessive friction and relieve the friction. This may require lubrication or loosening up the mechanical clearances to allow for smooth movement.


All control stops need to have thread locker or some other positive safety method applied so that they cannot move during flight thus blocking your controls. This happened to me in California with a student where I had no left cyclic control at 50feet agl and thought I would loose the ship, it would only go forward and right with very little control as the helicopter accelerated and leaned to the right. I took the controls from my student and was amazed that the helicopter survived the resultant controlled near-crash with no damage. My guardian angel was watching out for me once again. This experience once again shows the strength of the Rotorway helicopter design with its sturdy frame that protects the occupants.


The cause of the restriction was the passenger side left cyclic stop bolt. The aluminum hole was slightly oversized. The builder had tightened the lock nut but when the controls were run against the stops prior to engine start there was just enough play in the aluminum threads to allow the bolt to rock. When the bolt head moved upon contact with the tube stop, it shifted just enough to allow the jam nut to break it's jamming function and the bolt was able to back out with gravity and vibration as we flew. If the jamming function of the jam nut is lost, and the bolt can rotate, it can then back out and prevent control movement in that direction. I now advocate placing some removable (not permanent) thread locker on these threads to give a back-up for safety. Check your cyclic stop bolts and insure that they are properly secured and will not back out on their own.

The below photo shows where we hit first (diagonal skid marks to the right), tipped forward onto the nose of the skids (see Rocking Horse skids) under the landing gear hints and tips) then the helicopter pivoted around the front left skid about 45 degrees to the left with the front of the left skid digging out a large divot of sod (the dark clump in the photo). The deep skid impression was made as we settled back level onto the skids, can be clearly seen in the photo.

In this case the ground was very soft, as you can see in the photo. Instead of the left skid kinking at the front of the left landing gear weldment, which usually happens, the nose of the skid dug into the soft sod like a cookie cutter and as the ship pivoted around (tail moving to the left) the buried front left skid area, it cut out the piece of sod that you can see overturned in the photo.

This instance was as close to a roll over as one can get without actually going over. We found the reason for the control lockup and fixed it right there where the helicopter landed. We then did a very thorough pre-flight inspection looking for any damage and found none. After about an hour on the ground, we fired the helicopter back up, lifted off and resumed our flight training and continued without problems for the rest of the week when my student was soloed. After our flight I walked back out into the field with my camera to take the below photo so that others can see- proof positive- how the Rotorway helicopter reacts to a full touchdown emergency landing with forward ground speed. The impressions in the soft soil tell the entire story.

The photo above dramatically shows how the weight of the helicopter is transferred to the front left skid.
 

Even after all of the publishing of the control lockup issue that I experienced, some owners are still not checking their controls. On March 15, 2008 I was hired to provide insurance qualification training for the new owner of a 200 hour Rotorway 162F. This ship was being regularly flown and had been flown by a "Rotorway Flight Instructor" at a new flight school with very little experience. The insurance company required that the instructor that was to give the qualification training have at least 1000 hours in Rotorway Helicopters, for very good reason.

When I arrived at the airport I first gave the helicopter that I would be flying a very good safety inspection. There were several issues that I dealt with and adjusted. I told my student to remove the cyclic control cover panels so that I could inspect all of the controls. This ship had a fresh annual inspection so it had been "inspected" by someone "Qualified". The photo above shows what I found on this ship that was regularly flying and just recently with a "Rotorway Experienced" flight instructor!

The cyclic control stops had no jam nuts on the stop bolts, there was no lock tight, and I easily unscrewed them with my bare fingers, all four of them. These bolts are hanging upside down where gravity will cause them to unscrew. The fact that a flight instructor who is represented as being Rotorway qualified to students had flown this ship without even checking the controls is frightening. He appears to be a really nice guy and he is instructing Rotorway builders in their own machines, he just does not have the experience that only years of instructing and maintaining these machines gives.

Just because someone signs off an annual inspection does not mean that they actually performed the inspection.

Just because someone says that the are a Rotorway Experienced flight instructor, that may mean that they have the required 5 hours in type.

Above is another photo of the other cyclic control, it too had the unsecurred cyclic stop bolt just hanging there. These bolts were not installed according to the kit manufacturers instructions and drawings.

One other area where I experienced a control lockup in flight was with the donut-shaped collar around the main rotor shaft under the non-rotating swash plate on the Rotorway helicopter. This collar must be secured to the main shaft by clamping pressure so that it cannot slide up or down. In this case I was with a student when the collective controls locked in the near full-up position. This happened in an area where the wind was high and gusting higher as my student was making an approach to the fuel tanks on his ranch. Controlling the helicopter, a Jet Exec non-factory configuration, in the gusty winds was requiring a lot of collective input when all at once the collective locked in the near-full up position. It is important to note that the jet engine equipped ships vary greatly from the design of the Rotorway helicopter and their reliability history should not be compared with that of a Rotorway built to factory specs.


The helicopter began to climb, and climb fast, with the powerful turbine engine powering it's rotor system. I emphatically called out to my student "I've got it", those special words that I reserve for the times when I need the student completely off of the helicopter's controls. I took the controls and decreased the throttle on the Jet Exec to achieve a main rotor RPM of around 92 percent, thus producing less thrust and the helicopter settled to the ground where I was able to slide it on (it had the extended skid modification).

A word of caution here, we were in a life and death situation and the only way that I could stop the rapid climb was to reduce the main rotor RPM to decrease the lift being produced. Doing this in flight and especially in a high rotor pitch angle climb is very risky and if the rotor RPM is allowed to decrease much below that point the main rotors will stall and the helicopter will fall like a rock. I had no choice and did what I needed to do to cause the helicopter to descend and slide onto the surface.


Upon investigating the cause of the lock-up we discovered the problem. My student had purchased a rolled over helicopter in Texas. The torque on the nut securing the collar to the main rotor shaft had been checked by me when I arrived a the students home. The torque value on the NUT was correct but the collar still slipped down allowing the alignment forks to exit the top of the collar and rotate away from their slots in the collar. The forks now effectively blocked the collective control from moving the swashplate downward to lower the pitch on the main rotor blades.

Upon examination after the lockup we found that the clamping bolt had corroded threads. The bolt thread condition caused the nylock nut to achieve the proper torque, but before the nut was far enough onto the bolt to securely clamp the collar to the shaft. The person installing the collar must have used a defective bolt to secure it. I now gently but firmly pry down on the collar on every ship I apply downward pressure on the collar to insure that it has the proper clamping pressure so that it will not move. I also check the torque on both the nut and the bolt head to insure that both are at the proper setting to achieve the required clamping force on the collar.


The photo below was taken after we landed. You can clearly see the forks sitting out of their slots and resting on top of the collar which prevents them from being able to be lowered.

After we repositioned and securred the collar above and completed Ron's flight instruction, I headed to Pennsylvania to provide another student with advanced flight training. I was performing an airworthiness inspection on this student's Rotorway Exec 90 when I noticed the collar position looked too low. When I pulled full up-collective the fork came completely out of the collar. We checked the torque settings and they were incorrect for the nut and bolt head, they were loose.

This student had been flying it that way at altitude and if he had ever been put into the position of applying full up-collective the fork would have come out of the guide slots and rotated away from them. This would again have jammed the collective in the full-pitch position. Had that happened it could have ended up in an unhappy ending! Everyone should check the position and security of this collar. That was the second collar issue found in 2 weeks. The photo below was taken before we slid this second collar back into position and properly torquing the clamping bolt.

This method of securing the collar to the main shaft is very effective but the installation must be done to the factory standards. It is the responsibility of the owner/builder to check the integrity of the clampinb bolt to insure proper securring of the collar to prevent it from moving.

 

The photo above shows a properly placed collar and this builder also fabricated a reinforced collective scissor bracket. I have seen this bracket break in the past. The break occured at the 90 degree bend and is most likely from improper technique used in bending the bracket ears performed by the builder. Those bends should be radiused as per the factory drawings.
 

The following week I was off to Connecticut and of course now the first thing on this students ship that I checked was his locking collar. When I applied downward pressure on the collar with a piece of wood and a fulcrum the collar slipped down easily. We checked the torque on the nut and it turned and turned and turned but would not tighten. It took us nearly an hour to get the locknut with stripped threads off the bolt and as you can clearly see in the photo below the installer had used a bolt that was the next size longer than called for in the factory specs.

When the nut was tightened it ran out of threads and rode up onto the shank of the bolt stripping the nut's threads. With the threads stripped the collar could not apply the required clamping force onto the main rotor shaft. It could have eventually slid down to the point that the forks could clear the collar, rotate, and jam the collective in the full up-collective position.

I urge everyone to check their collars prior to flight. This series of loose collars is not common because I have only found one loose clamping ring since.

Collective Pocket.

There is one area on the Rotorway where sometimes there is not enough clearance for the pilots left hand during the initiation of an auto-rotational descent. This is the area of the left collective pocket against the outer wall of the cabin. If the throttle is too close to allow the back of the pilot's hand and knuckles to be able to fully lower the collective into the pocket to achieve full negative pitch on the main rotor blades, some adjustment or modification to this area may be desireable. During auto training the student might be forced to slide his/her hand to the front end of the throttle and hold it with the tips of the fingers if there is not enough room in this area.

I have found that a Dremmel tool with an abrasive disc cutter is the tool of choice for this simple modification. I make a cut from the front of the pocket to the rear on the flat bottom just inboard of the curved section where the fiberglass makes the transition from the horizontal floor to the vertical wall of the pocket. I then cut both sides up to the top of the pocket and then out to within about 1/4" inboard from the outer body skin panel. I then finish the removal by cutting along the outer body panel and about 1/4" in from the edge.

I leave the 1/4" piece so that there is something to attach new fiberglass to when the new pocket is later formed. This is usually accomplished by utilizing the piece of fiberglass that was removed but can now be moved outward as far as possible to allow clearance for the pilots hand and knuckles when the collective is fully lowered. It can then be glassed in, smoothed and painted for a factory finish. Since we usually do not take the time to re-glass the pocket during training, we place some duct tape over the cut fiberglass edges to protect the pilots knuckles.

Check the fit on your collective and determine if you can fully lower it into the pocket with your hand around the throttle. I want to thank Todd Mason for sending the below photo of his side pocket with the section removed. This gives him the needed hand clearance for autos and he can take care of the esthetics later, SAFETY FIRST!!!!!!

 
To see photos of a comparison of the stock and modified pockets
 
 
Clark Richter provided us with a great tutorial on how he modified the collective pocket on his Rotorway 162F
Clark's Pocket Mod Page 1 (Click Picture)
Clark's Pocket Mod Page 2 (Click Picture)
 
DISCLAIMER:

The material on each page is the opinion of the author only and any actions taken by the reader relating to information on this site is the responsibility of the builder.