Enstrom Corner
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Dennis, When at engine RPM 1400 to 1500 the main rotor will begin to turn and settles at a rotor RPM of 25 with it disengaged. The manual doesn't go into great detail on belt tightness when disengaged. It is more concerned with how it is when it is engaged. My question would be at 25 RPM is there too much friction on the belt to hold it back at idle? I know the engineers have the definitive official answer, but just trying to get some idea. After engaging and then disengaging the clutch the rotor will continue to turn at near married needles and won't go below. I would assume that is because of the high inertia and the slight friction on the belt at engine idle. I wonder why they didn't include a rotor brake? I know they don't want the R22 idling without engaging the rotor so I was wondering if Enstrom is the same.
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OK I read SIL 0168. I'm confused a little. It says Aeroshell 14 is preferred, but can't be used with Lamiflex bearings so Aeroshell 22 is OK as an alternative. So is Aeroshell 22 OK to use as a universal grease for all the bearings? I would like to get some feedback from other owners on this. This is my first ownership of a helicopter and I was told that it was wise to give the bearings a shot of grease now and then between annuals. What is the normal practice of some of you hands on pilots?
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Aeroshell 22 is more expensive but it is the best grease to use on all the bearings. If you are doing the greasing yourself don't forget the clutch cable or the bottom pulley.
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I do prefer synthetics. I've been a fan of Amsoil in my cars for over 30 years. Mobil 28 costs a little bit more than Aeroshell 22 so that isn't a problem. Why would Enstrom engineers prefer Aeroshell 14? Do I have to clean out all the Mobil 28 before using Aeroshell 22?
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LV,
It is my understanding that you have to purge the bearings of the old grease when you change greases. I am not a mechanic so I am not sure of the whys and wherefore's of these.
Next there is no such thing as too much grease. I worked for a flight school where we greased the rotor heads every morning. And the heads would always take some fresh grease.
It is my understanding that you have to purge the bearings of the old grease when you change greases. I am not a mechanic so I am not sure of the whys and wherefore's of these.
Next there is no such thing as too much grease. I worked for a flight school where we greased the rotor heads every morning. And the heads would always take some fresh grease.
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Enstrom belt drive.
Having another stab at your problem ... as the blades are turning with the system disengaged, you have the belt too tight. The crankshaft drive pulley should turn easily inside the belt when the system is disengaged with the belt actually able to flop around slightly.
A second possibility is the drive side of the belt has become 'sticky' with ageing. A quick cure would be a good dose of French Chalk, but the overall problem is too tight adjustment.
PS. From inspection are all the belt grooves in good condition with no detached tearing on the drive face. How old is the belt?
Regards & good luck. Dennis K
A second possibility is the drive side of the belt has become 'sticky' with ageing. A quick cure would be a good dose of French Chalk, but the overall problem is too tight adjustment.
PS. From inspection are all the belt grooves in good condition with no detached tearing on the drive face. How old is the belt?
Regards & good luck. Dennis K
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What is French Chalk? I'll take a closer look at belt and logs to see how old it is. On another note I finally was able to bleed my dampers. Great tool by Bayard, by the way. I got about 1 to 2 cc of air out of two of the dampers and less than 1cc out of the last. Is that enought to cause issues. Should I expect to see some improvement when I take it out tomorrow?
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Aeroshell 22 is not the best grease for reciprocating bearings apparently. There is increased fretting of the bearing surfaces with clay based greases (which 22 is). Soap based greases perform better in this application so I use aeroshell 14 in the tail rotor feathering bearings and the main rotor flapping and lead-lag bearings. As grease can leak fom the main rotor feathering bearings and there is evidence aeroshell 14 can damage lamiflexes, the main rotor feathering bearings get 22. The fretting problem appears worst in the head bearings but doesnt seem a problem in the feathering bearings. I guess its to do with water ingress.
Everything else gets 22.
It is necessary to at least purge on changing from 22 to 14.
I dont know why soap and clay based greases dont mix, but apparently they dont.
Everything else gets 22.
It is necessary to at least purge on changing from 22 to 14.
I dont know why soap and clay based greases dont mix, but apparently they dont.
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Dennis,
I took a closer look at the belt and clutch system. No cracks present in tracks. Idler pulley turns freely so apparently the belt is sticky. Again, what is french chalk and what are the benefits of its use?
Dirk
I took a closer look at the belt and clutch system. No cracks present in tracks. Idler pulley turns freely so apparently the belt is sticky. Again, what is french chalk and what are the benefits of its use?
Dirk
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Can't advise, as I've never used it on a helicopter.
But, I have used it on the belt drive of my hifi turntable, and it worked, eliminating the start up rumble and smoothing the drive take up.
But, I have used it on the belt drive of my hifi turntable, and it worked, eliminating the start up rumble and smoothing the drive take up.
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Just sprinkle half a handful of chalk around the inside area of the belt, over the grooves. Rotate the head as you do it so the belt goes around, disengaged clutch obviously.
Then beat the belt with the back of your hand to make sure there is no pile of chalk in one place. That's how I did it on mine.
Then beat the belt with the back of your hand to make sure there is no pile of chalk in one place. That's how I did it on mine.
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What symptoms were you experiencing that led you to use talcum powder on your belt? What were the results?
Adding french chalk effectively adds lubrication to the belt and the whole clutch becomes much more behaved. You will still get a screeching noise whilst engaging though. I have over 1600 hours on the 280C.
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Thanks. Getting a warming spell this weekend maybe I'll get a chance to look at it and put some baby powder on it. With your experience did you ever bleed the dampers? If yes then how much air is too much air. I bled mine and got 1 to 2 ccs of air out of 2 of them and 1 cc out of the other. I'm anxious to see if that will make any difference for me. I also got all my oleos setup per Bayard Dupont's instructions as well. If you did bleed them yourself, did you use the two syringes and did you cycle the dampers and bleed them again after using the tools?
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La Chalk Francais
Apologies for having to drop out ... mainly due to work!
The infamous French Chalk (normally white) is available from major parts factors, although the two tubs I had to buy this week were a horrid 'yellow' ... but fashion aside, the stuff works especially well when used on the Enstrom drive system and is correctly applied. Flying serial number 1104 yesterday even with a new pilot, rotor engagement was totally silent throughout the whole engagement process. The chalk also helps soak up unwanted engine oil in the drive belt compartment.
But to re-state. The belt system MUST be adjusted correctly since there should be nil 'dragging' of the M/R blades at engine idle 1400 - 1500 ... and certainly not to the extent earlier advised where engine and rotor speed become 'married.' .................... now back to the grind stone! DRK
The infamous French Chalk (normally white) is available from major parts factors, although the two tubs I had to buy this week were a horrid 'yellow' ... but fashion aside, the stuff works especially well when used on the Enstrom drive system and is correctly applied. Flying serial number 1104 yesterday even with a new pilot, rotor engagement was totally silent throughout the whole engagement process. The chalk also helps soak up unwanted engine oil in the drive belt compartment.
But to re-state. The belt system MUST be adjusted correctly since there should be nil 'dragging' of the M/R blades at engine idle 1400 - 1500 ... and certainly not to the extent earlier advised where engine and rotor speed become 'married.' .................... now back to the grind stone! DRK
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Dennis and others,
I got some baby powder that was just talc and no corn starch. I tried to get some on the belt, but did discover the belt was coated in lube cast off and sticky. It was easily slid along the pulleys, however. I also had a friend hang on to the main rotor at idle and all it took was a very light touch on the finger tips. So apparently the belt needs to be cleaned or just use more talc. It isn't a big issue at the moment because winter is gone so no need to warm up the engine occasionally.
For those new to Enstroms or thinking about joining us as an owner I just wanted to confirm what the experts have been telling me about the ground rock. I followed Bayard Dupont's guide on servicing the oleos and ended up having 400psi nitrogen in the front and 450psi in the rear. That is what is recommended for the F models, but mine is a 1977 280C with extensions. I purchased the damper bleeder tools and followed the simple procedure. I got 1 to 2 CC air from 2 of the dampers and 1 CC from the other. Let me tell you this helicopter is a whole different machine. Baby butt smooth on run up and hands off hovering. It makes a lot of difference when you bleed those dampers. Funny thing is the lamiflex bearings were replaced before I took delivery so you would assume the mechanic would have handled that. NOPE, just one of many things that were not handled by JL. Today I found the drain plug loose on the tail gear box and the wrong unauthorized fluid in the gear box. Any comments on Swepco 201? That's what was in it and it is not on the approved list. There is no need for track and balance now, but I think I am still going to permanently install the sending unit and sensors of the PB-3 so I can continually monitor any changes on my smart phone.
I got some baby powder that was just talc and no corn starch. I tried to get some on the belt, but did discover the belt was coated in lube cast off and sticky. It was easily slid along the pulleys, however. I also had a friend hang on to the main rotor at idle and all it took was a very light touch on the finger tips. So apparently the belt needs to be cleaned or just use more talc. It isn't a big issue at the moment because winter is gone so no need to warm up the engine occasionally.
For those new to Enstroms or thinking about joining us as an owner I just wanted to confirm what the experts have been telling me about the ground rock. I followed Bayard Dupont's guide on servicing the oleos and ended up having 400psi nitrogen in the front and 450psi in the rear. That is what is recommended for the F models, but mine is a 1977 280C with extensions. I purchased the damper bleeder tools and followed the simple procedure. I got 1 to 2 CC air from 2 of the dampers and 1 CC from the other. Let me tell you this helicopter is a whole different machine. Baby butt smooth on run up and hands off hovering. It makes a lot of difference when you bleed those dampers. Funny thing is the lamiflex bearings were replaced before I took delivery so you would assume the mechanic would have handled that. NOPE, just one of many things that were not handled by JL. Today I found the drain plug loose on the tail gear box and the wrong unauthorized fluid in the gear box. Any comments on Swepco 201? That's what was in it and it is not on the approved list. There is no need for track and balance now, but I think I am still going to permanently install the sending unit and sensors of the PB-3 so I can continually monitor any changes on my smart phone.
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Regarding collective trim
Thanks for all your valuable information. I value your experience. I need some clarification on the rigging of the collective trim. Up till now, since the collective friction in on the left side I would hold down on the co-pilot collective then release the friction since the collective would pop up with force while on the ground. I did some research and read in the maintenance manual for the 280F that when the collective trim is adjusted correctly the collective should not rise when the friction is released. Mine pops up with force so it is difficult to release the friction when the co-pilot collective is removed. So the manual said to back off the spring pack to balance the forces. I have loosened the spring pack so far that there are no threads showing on the top and the collective still pops up when the friction is released. The only way to get it to stay down without the friction was to adjust the position of the spring pack more towards the center point, just slightly over center. Still when I pull the collective up a little the force is quite a bit coming up. When flying slow it gets quite tiring holding the collective down or while waiting for departure clearance in a hover. My question to you experienced owners is what is the normal behavior of the collective and is the spring pack adjustment to balance forces only for in flight? Does your collective pop up on the ground or ease up? I know the spring isn't weak, if anything it is too strong. Do any of you use the collective friction in flight, even though there is a placard that says not too. In the 280C maintenance manual description it says the friction is for in flight forces so which is correct?