Our Views On The Cog Belt Concept

The decision to add this system to our ship was a no brainer
for us to make after doing the math.

 
Being that we don't have any experience in the aviation field aside from building the ship at the time,
we had to look at the Pro-Drive Cog Belt vs Chain drive thing in black and white to make a decision.

We aren't aviation experts by any means but we do possess something called common sense and it says, you weigh the pros and cons and then take the positive result and run with it hoping one has made the right decision.

This is a real can of worms for alot of folks out there and from what information we've gathered on the two systems it remains our best shot at having a long happy life with our ship.

With a chain drive installed per factory's strong recommendation it will most likely leave us with a few potential problems.

The odds that our chain oil bath is not going to leak isn't very good.

In a personal poll of talking to owners and watching the PRA site at the time and any other source
of information we came across

there are only a very small amount of people that claim to have been successfull
in not having leaks from their chain drive factory setups.

Here's the hows and whys we used to make our decision:

If we keep our chain drive:

Chances are we will have potential problems from this system,
even if we play by all the rules is what many of the old timers told us.

Should the chain drive setup leak oil:

1	Oil will saturate the exhaust pipe wrapping causing a major maintenance  problem which there is no easy method at all to keep up with short of an R&R of the exhaust system to clean the pipes and change the heat wrap and if not done in and on time will inevitably for sure cause a fire which we will more than likely will not be able to put out most likely causing the loss of our ship to say the very least.
2	Oil will cause the main engine drive belts to slip causing a maintenance and possible severe power loss.
3	Oil will cause the alternator belt to slip causing a voltage and or maintenance problem with the potential to cause a forced landing and has the potential to shut down of the engine should the voltage drops below FADEC unit 1 and 2's voltage requirements.  With this ship running with all the bells and whistles on it wouldn't take long to exhaust this ships little battery in our view.
4	Oil will cause the fan drive belt to slip and causing a maintenance problem and potential to overheating engine.
5	Oil will cause our radiator to become a dust collector inevitably causing a maintenance and overheating problem.  From the experiences we have had with small engines of today if they're allowed to overheat the engine will suffer severe damage in the blink of an eye.
6	Oil will possibly wash out the grease from our upper clutch bearing prematurely causing wear and causing it to overheat and aid and or cause potential shaft breakage.
7	Oil leaks will make keeping the ship clean a nightmare, everything will collect an oil film and dirt will attach itself to it making it a living hell to take care of.
8	Oil will cause a loss in tail rotor rpm.  A real big problem to deal with on our little ships.

We will have air flow blockage from the presence of the chain oil bath which:

1	Causes the engine to run hotter.
2	Causes the bearings to run at higher temps.
3	Causes everything such as wiring, sending units, cooling hoses and etc. to endure higher temps.
4	Causes us to have to cut large holes into the lower cowling to allow more air in to supplement the airflow through the radiator to to help prevent overheating.
5	We will have engine and component access blockages.
6	It limits site and access to several major components making everything from preflight to engine maintenance much more difficult.

    We will have a high cost of replacing parts of the setup every 100 and 250 hours providing all goes as planned

1	Replacement of the chain at 100 hours and sprocket gears every (250?)  hours at a cost of   $???.??
2	Potential for problems with the chain coming apart
3	Potential for main rotor shaft lockups should the chain break and wrap its self around the shaft and not the sprocket
4	Potential extreme damage from the chain flying apart causing mega damage to components such as fuel tanks our head and etc.

Many miscellaneous things to deal with like:

1	Preflight preoiling of the chain
2	On preflight, having to check for the presence of the e-clip thru and oil coated Plexiglas window we can't get to with out removing the rear doghouse at the very least.
3	On preflight having to check the entire length of chain for missing or damaged links.
4	Not being able to check the main sprocket gear or hub bolts without a major teardown of the ship and removing the top of the siliconed down oil bath (a major undertaking).
5	Alot of noise and vibration from that chain whirling around

If we go against the factory recommendations and install a cog belt drive it:

1	Eliminates the high potential oil leak problem
2	Eliminates the air restrictions of the oilbath case
3	Eliminates the preflight preoiling
4	Eliminates inspecting the chain assembly during post and pre flight
5	Eliminates main engine belt slippage potential should oil leak
6	Eliminates fan drive belt slippage should oil leak
7	Eliminates alternator and water pump drive belt from slippage should oil leak
8	Eliminates tail rotor slippage should oil leak
9	Eliminates potential for grease being washed out of the upper clutch bearing should oil leak
10	Eliminates the potential for oil soaked exhaust header heat wrap should oil leak
11	Eliminates the potential for an unstoppable fire from oil all over engine components and hull interior
12	Eliminates 21 pounds of weight from the ship
13	Exposes the main rotor hub and sprocket for post and pre flight inspection
14	Exposes several components making them easier for inspection
15	Allows several components to become user friendly for maintenance
16	Removes the chain noise and from the system
17	Removes a rough vibration from the chain meshing with the sprockets

Down side to installing the cog belt

1	Fuzz from the first hour or two of running the belt, easy to remove with compressed air and a dust cloth
2	Small vibration from the belt meshing with the cog sprockets, possibly causing harmonic vibrations damage.
3	No access panel holes in lower cowl panels to aid in inspections
4	No access panel holes in lower cowl panels to aid in the event of putting out a fire from electrical, fuel, or antifreeze fires
5	Potential one time investment for the life of the ship of under $3,000.00
6	No discount for having made the ship a much lower risk to the insurance company
7	Possibly loosing any monies in the event of an accident from our insurance co for having installed a system not approved by RotorWay
8	Possibly having our insurance cancelled for having an aftermarket system in our ship not approved by RotorWay to which there are several parts and systems all ready installed within that aren't approved
9	Having a safer more reliable ship with less downtime, upkeep and cost to operate and being called a weenie for taking the lesser chance of two critical choices
10	Putting up with accusations of belonging to a cult

To Donna and I, all this adds up to

 
less maintenance, less monies spent out, a safer cooler running ship
and most of all, it adds some
piece of mind.

 
There are several more things we could have picked at and praised, I'm sure on both systems, but this was more than enough to make a decision for us.  There's even some guy running around in Africa that may for the most part be alive today because this system was installed in a ship that rescued him.  The pilot said he wouldn't have made the pickup if he hadn't had the Cog Belt system in his ship.  You'd have to get it from the horses mouth to get the story correct and in its entirety but I'm told it's true and it all adds up to us.

The things that kept us from making the decision buying the Rotorway ship sooner was:

#1	The oilbath / chain drive setup
#2	The fact that it wasn't turbo charged, since we live in the foothills of the Smoky Mountains

We waited about a year longer on RotorWay

to get a turbo system going after we heard they might be adding them to their ships.  To us it's the only thing this little ship lacked now that there's an alternative to the chain drive factory system.  Sure wish we had the monies to add the ACIS system to our ship (wish it was available when we financed ours) but
this thing has already gone way over budget
to date so we will have to go without it for now.

 
Right or wrong we used the same minds to pick the Cog Belt system
as we did to pick the RotorWay ship

and all the other things we installed and built into our ship.  We feel we made the right choice and we're the ones that have to live with that decision and take responsibility for us and any passengers we carry.   We feel good about our decision not only on the outside but on the inside in our gut where it counts most and until something better comes along or we see something bad arise for this system were sticking to it.

 
This isn't an endorsement in any means Nor is This isn't a political Decision
it's most of the information we used to make our decision.

Folks your on your own to make your decision.

We only hope this aids you in making it as it did us.

This thing was super easy to install

To date weve only had to ajust it once since we began flying our ship.

That was removing a shim or two after the belt had broke it's self in and using this tool that coms with it, its a piece of cake to do.

Each and every time we checked the tention on our cog belt system
it checked out to the exact tentions John Spurling at Pro Drive stated it would.

It doe's in fact get tighter as it gets hotter and you can see that by the specs
we had printed on our airframe at the time in the above photo.

As of July 2004 we had 96 plus hours on our ship and It's flown in temps from 14 to 97 degrees

and it's checked out tention wise at every tempreture acording to the Data Pro-Drive provides with the installation material right up until the flight we made when our shaft broke.

END