OC Bob
05-11-2004, 07:57 PM
Hi Everyone,
Here is a cheap way to fix any V1 30 or 50 head for certain. This fix will make your V1 head as good as a V2 head. In some cases it will even work out better then the V2 head is. And it only costs about 30 cents, and takes about 1 hour to do. You will probably have what you need to do this fix in your parts draw as well.
Put two thin washers against the dampers, between the dampers and the barrels. The barrels I refer to are the ones that ride on the back blade grip bearings in each grip. Put one thin washer on each side of the spindle. Tighten the spindle nuts after the washers are in place, and the last two or three turns of the spindle nuts should pull the whole thing tight, as you turn them down to the bottom. As you tighten the nuts down, it should tighten the whole assembly up on your V1 spindle, the last few turns of the spindle nuts. This presses the washers you added against the dampers firmly. Even with crappy dampers in the head, the dampers will now work well loaded with the washers pressed against them slightly.
If you get a little grip drag after adding the washers while sitting static on the bench, pull out on the grips hard and then feather them back and fourth. If they are now pretty free with just a slight drag when pulling out hard on them and fethering them, they will be fine in flight. The blade weight when running pulls the grips out very hard against the thrust bearings. The slight grip drag from being tight when sitting static goes completely away from the load of the blade weight when running. The blade weight load on a V1 raptor when running is what creates the blade grip play on the spindle anyway. It unloads the barrel off the damper some when it is pulling out under load while running. This play that develops while flying between the barrel and the damper is actually what causes the bad woofs in the V1's at high rotor speeds. The blade dynamic weight gets heavier the faster the rotor speeds are turned. And the play increases between the barrel and the damper from this issue.
If you want a complete fix which will make your V1 head as good as the head of a V2, glue the outside of the two large carrier bearings in each blade grip. This is to fill the little bit of loose space between the grip and the carrier bearing. This bearing play problem was pretty well fixed in the V2 blade grip. This is what the metal blade grip upgrades primarily do on the V1 heads. Also metal grips don't streach a little like the plastic ones do when running. So the play between the barrel and the damper doesn't change when running the rotor at fast speeds. Use slow CA glue to glue the outside of the bearings in the plastic V1 grips. When doing this don't get the CA in the bearings. A thin coat of CA goes between the outside race of the two big bearings, and the grip itself. This is just to fill any of the space between them, and to eliminate the little bit of play between them. If you do this correctly it make the bearing and plastic grip as tight as metal ones fit around the bearings, or as tight as a V2 grip and bearing assembly is. Then if you add two washers against the dampers, one on each side the spindle the right width, your V1 head will perform exactly like a V2 head. If you get the fix done exactly right, the V1 head will perform better then some of the V2 heads, in many instances.
You can try a blade grip flip, but that works hit or miss. Here is why. When you flip the grips what actually happens is this. The plastic molding of the blade grips are a little different when rotated and run 180 degrees reversed then when run normally with the pitch link in trail. When you reverse the grips to leading, you rotate the grips 180 degrees. The wear in the plastic grips caused by flying from the bearing loads is now shifted in the grip. To an entierly new spot in the grip which is not worn from running yet. This usually tightens up the grips, just enough again on the bearings while running against the dampers, to eliminate enough spindle play to stop the woofs at moderate to high rotor speeds. Usually the woofs will start again, or may never stop at all with the flip, if you had a real loose V1 spindle assembly on your V1 head from the start. This is why the blades will stop woofing sometimes when you flip the grips on some V1's. Other times it won't stop the woofs at all because the system was too loose from the start. In many cases even with the grip flip, the blades will continue to woof anyway. This is because the system won't get tight when the flip is done. Again, simply because your specific V1 head system was too lose to begin with anyway. I also have to add this item. A set of blades with bad CG will amplify the woof trouble. Most rotor blade CG trouble is caused by the placement of the blade mounting bolt hole, at the end of the rotor blade. A little off, just a little, and the blade runs out of true center of pressure. There is a specific blade MFG. which sells a lot of rotor blades. In many of there blade sets they have the mounting hole off just a little bit. These blades will typically woof badly on a V1 at high rotor speeds. This head fix will eliminate the CG mounting hole trouble these make of rotor blades have as well.
Glue the outer races of the carrier bearings in the grips with slow CA lightly. This is to fill the play between the bearing and the plastic grip. An easy way to do this is to use an old spindle. Assemble the bearings in the proper order on the old spindle. Apply the glue to the outer races of the big carrier bearings now, and then pull them into the grip in the right order, in one fast pull. Now install the two phillips bearing retaining screws and you are done. Let the glue dry for about 15 minutes. Then find a set of washers that fit over the spindle and seat well against the dampers. Put them in place and then put the grips back on. Tighten the spindle nuts down now and this will make the entire assembly tight, as you tighten the spindle nuts the last few turns.
Again, if you end up with a awful lot of grip drag, as you feather the each grip static with no load while sitting on the bench, the washers you used are probably a little too wide. There should be just a little grip drag once you are done at each blade grip when feathered. This assures you that the spindle barrel is firmly aginst the washer, and the washer is firmly against the damper. Then if you pull out hard on the grips and feather them, they should only have a little drag. If so it is now set correctly. When flying the grips will load against the thrust bearings and run perfectly. If you glued the bearings in the grips right, and have the right thickness of washers against the dampers on the spindle, it will never woof again. Even at very high rotor speeds. And now your V1 30 and 50 heads will fly exactly like the V2 heads. You won't be able to tell any difference at all between the two helicopter heads.
If the blade grip flip was really the cure all for the problem, there would never have been a V2 head introduced to replace the V1 head. This washer process also works for some of the V2 heads. Ones which have a little play between the damper and barrel from the factory. The grips on a V2 head make the bearings tight in the grips, and has essentually fixed that trouble the V1 has. However once in a while the V2 systems are not loaded enough against the dampers to eliminate all the spindle damper play. If a V2 head has a little to much spindle play from the factory, you must use only very thin plastic blade washers. Ones that will fill just the little bit of spindle play some V2's have out of the box. They are not all completely perfect either, but are much better then the V1's heads out of the box. If you have a V2 that woofs a little here and there, a very thin set of plastic blade washers will tighten it up, and stop any woofs it may have as well. If you get the V2 spindle damper loads a little to tight with the washers, the helicopter will shuffel with cyclic inputs a bit. You just want to tighten the V2's that are loose up slightly, if you were unlucky enough to get one with a head a little loose from the factory.
Additionally if you do this fix you don't need to flip the blade grips to leading. This will allow the geometry of the mixers in the head to work as it was suppose to from the start. The helicopter collective and cyclic, along with clearence of the links stays the same and nothing changes. Except you get rid of the woofs, and the old V1 helicopter heads come alive and responds cleanly to cyclic control now. You will feel and see the difference instantly.
OC Bob
Here is a cheap way to fix any V1 30 or 50 head for certain. This fix will make your V1 head as good as a V2 head. In some cases it will even work out better then the V2 head is. And it only costs about 30 cents, and takes about 1 hour to do. You will probably have what you need to do this fix in your parts draw as well.
Put two thin washers against the dampers, between the dampers and the barrels. The barrels I refer to are the ones that ride on the back blade grip bearings in each grip. Put one thin washer on each side of the spindle. Tighten the spindle nuts after the washers are in place, and the last two or three turns of the spindle nuts should pull the whole thing tight, as you turn them down to the bottom. As you tighten the nuts down, it should tighten the whole assembly up on your V1 spindle, the last few turns of the spindle nuts. This presses the washers you added against the dampers firmly. Even with crappy dampers in the head, the dampers will now work well loaded with the washers pressed against them slightly.
If you get a little grip drag after adding the washers while sitting static on the bench, pull out on the grips hard and then feather them back and fourth. If they are now pretty free with just a slight drag when pulling out hard on them and fethering them, they will be fine in flight. The blade weight when running pulls the grips out very hard against the thrust bearings. The slight grip drag from being tight when sitting static goes completely away from the load of the blade weight when running. The blade weight load on a V1 raptor when running is what creates the blade grip play on the spindle anyway. It unloads the barrel off the damper some when it is pulling out under load while running. This play that develops while flying between the barrel and the damper is actually what causes the bad woofs in the V1's at high rotor speeds. The blade dynamic weight gets heavier the faster the rotor speeds are turned. And the play increases between the barrel and the damper from this issue.
If you want a complete fix which will make your V1 head as good as the head of a V2, glue the outside of the two large carrier bearings in each blade grip. This is to fill the little bit of loose space between the grip and the carrier bearing. This bearing play problem was pretty well fixed in the V2 blade grip. This is what the metal blade grip upgrades primarily do on the V1 heads. Also metal grips don't streach a little like the plastic ones do when running. So the play between the barrel and the damper doesn't change when running the rotor at fast speeds. Use slow CA glue to glue the outside of the bearings in the plastic V1 grips. When doing this don't get the CA in the bearings. A thin coat of CA goes between the outside race of the two big bearings, and the grip itself. This is just to fill any of the space between them, and to eliminate the little bit of play between them. If you do this correctly it make the bearing and plastic grip as tight as metal ones fit around the bearings, or as tight as a V2 grip and bearing assembly is. Then if you add two washers against the dampers, one on each side the spindle the right width, your V1 head will perform exactly like a V2 head. If you get the fix done exactly right, the V1 head will perform better then some of the V2 heads, in many instances.
You can try a blade grip flip, but that works hit or miss. Here is why. When you flip the grips what actually happens is this. The plastic molding of the blade grips are a little different when rotated and run 180 degrees reversed then when run normally with the pitch link in trail. When you reverse the grips to leading, you rotate the grips 180 degrees. The wear in the plastic grips caused by flying from the bearing loads is now shifted in the grip. To an entierly new spot in the grip which is not worn from running yet. This usually tightens up the grips, just enough again on the bearings while running against the dampers, to eliminate enough spindle play to stop the woofs at moderate to high rotor speeds. Usually the woofs will start again, or may never stop at all with the flip, if you had a real loose V1 spindle assembly on your V1 head from the start. This is why the blades will stop woofing sometimes when you flip the grips on some V1's. Other times it won't stop the woofs at all because the system was too loose from the start. In many cases even with the grip flip, the blades will continue to woof anyway. This is because the system won't get tight when the flip is done. Again, simply because your specific V1 head system was too lose to begin with anyway. I also have to add this item. A set of blades with bad CG will amplify the woof trouble. Most rotor blade CG trouble is caused by the placement of the blade mounting bolt hole, at the end of the rotor blade. A little off, just a little, and the blade runs out of true center of pressure. There is a specific blade MFG. which sells a lot of rotor blades. In many of there blade sets they have the mounting hole off just a little bit. These blades will typically woof badly on a V1 at high rotor speeds. This head fix will eliminate the CG mounting hole trouble these make of rotor blades have as well.
Glue the outer races of the carrier bearings in the grips with slow CA lightly. This is to fill the play between the bearing and the plastic grip. An easy way to do this is to use an old spindle. Assemble the bearings in the proper order on the old spindle. Apply the glue to the outer races of the big carrier bearings now, and then pull them into the grip in the right order, in one fast pull. Now install the two phillips bearing retaining screws and you are done. Let the glue dry for about 15 minutes. Then find a set of washers that fit over the spindle and seat well against the dampers. Put them in place and then put the grips back on. Tighten the spindle nuts down now and this will make the entire assembly tight, as you tighten the spindle nuts the last few turns.
Again, if you end up with a awful lot of grip drag, as you feather the each grip static with no load while sitting on the bench, the washers you used are probably a little too wide. There should be just a little grip drag once you are done at each blade grip when feathered. This assures you that the spindle barrel is firmly aginst the washer, and the washer is firmly against the damper. Then if you pull out hard on the grips and feather them, they should only have a little drag. If so it is now set correctly. When flying the grips will load against the thrust bearings and run perfectly. If you glued the bearings in the grips right, and have the right thickness of washers against the dampers on the spindle, it will never woof again. Even at very high rotor speeds. And now your V1 30 and 50 heads will fly exactly like the V2 heads. You won't be able to tell any difference at all between the two helicopter heads.
If the blade grip flip was really the cure all for the problem, there would never have been a V2 head introduced to replace the V1 head. This washer process also works for some of the V2 heads. Ones which have a little play between the damper and barrel from the factory. The grips on a V2 head make the bearings tight in the grips, and has essentually fixed that trouble the V1 has. However once in a while the V2 systems are not loaded enough against the dampers to eliminate all the spindle damper play. If a V2 head has a little to much spindle play from the factory, you must use only very thin plastic blade washers. Ones that will fill just the little bit of spindle play some V2's have out of the box. They are not all completely perfect either, but are much better then the V1's heads out of the box. If you have a V2 that woofs a little here and there, a very thin set of plastic blade washers will tighten it up, and stop any woofs it may have as well. If you get the V2 spindle damper loads a little to tight with the washers, the helicopter will shuffel with cyclic inputs a bit. You just want to tighten the V2's that are loose up slightly, if you were unlucky enough to get one with a head a little loose from the factory.
Additionally if you do this fix you don't need to flip the blade grips to leading. This will allow the geometry of the mixers in the head to work as it was suppose to from the start. The helicopter collective and cyclic, along with clearence of the links stays the same and nothing changes. Except you get rid of the woofs, and the old V1 helicopter heads come alive and responds cleanly to cyclic control now. You will feel and see the difference instantly.
OC Bob