Heat Shields

Upper heat shields

There is question here whether or not you need to install these upper heat shields. 

It makes sense to have them but over veried amounts of time they tend to break away from their mounting brackets.  What they're supposed to do we're told is protect the fuel tanks from being subjected to a super hot spew of fire being shot at them in the event that the exhaust pipes burn through at the top of the tubes where they turn around in a 180 degree turn.  I asked Tom Smith about this and he said since the use of better exhaust pipe material they don't have that problem anymore but it's better to be safe than sorry and I agree.

Another thing they're supposed to do is keep gasoline from spilling onto the exhaust pipes in the event you have a bad hair day and don't allow the engine to cool down enough before refueling, another good point and I can see this happening rather easily.

I'm not sure if it's intended or not but if an upper exhaust gasket were to blow out it would, to a degree, protect the fuel tanks here too so we decided to go ahead and install them.

A down side to having them installed is should one break loose it could get into the main drive belts and shred them causing you a very serious unexpected problem.

When you make these you must be sure that they do not extend into the main frame tubes at all because the drive belts need this area for that time when they start fluttering as you go up and down in rpm.  There's something the ship does during this time that causes them to vibrate between 2500 and 3000 rpm.

 
I'm not real sure what happens here but I can tell you it's so because during the first engine runup ours did it and the belts rubbed paint off the frame particularly on the pilots side of the ship
<pout>.

Later on when we started flying our ship we made the decision to chuck the upper heat sheilds.

They were a pain in the butt to work around and we we're afraid the main engine belts would get into them and fray.

This is a very personal decision and its one you need to make for yourself. 

I'm told there is an aftermarket side idler pulley thats made to help during these times.  Some say it has great success and some say it may cause a frame crack so your on your own here to decide whether or not to install one.

From what I gathered from some experienced long time builders back in the old days, the Scorpion guys used to use these idler pulleys and experienced frames cracks because there isn't enough room for the belts to do there oscillation thing and that resulted in outward stress being put on the frame which eventually lead to the tubing cracking.  Looking at the Scorpion and the 162 there isn't a whole lot of change in the frame design that I can see so we're going to hold out on this until a later date when we have more time to dig into it.

Lower heat shields

For starters here you may find the patterns RotorWay provides in the kit aren't right if you make these parts from them.  

Patterns are for general reference and not an absolute size.

We didn't catch this anywhere in the building books, videos or prints but its there and we found this out the hard way, by having to make parts over again so don't forget this or you will be doing the same thing.

We made some of these parts twice trying to obtain a close fit like the instructions tell you
and in the end it was for nothing, very frustrating!

First we went by the patterns and it didn't work out so we made them again to a perfect fit only having to later remove them again and enlarge the holes to allow for the engine to move forward as the main belts stretch later when we began to run the ship. 

When you fit them around the exhaust pipes you need to figure in that as the main engine drive belts stretch your going to be moving the engine forward to tighten them up so you will need to make the forward part of the holes about 3/4 to 1 inch bigger.

This is something RotorWay forgets to tell you about during construction of these parts.

Later we installed the Pro-Drive Electric Clutch and to date (70 or so hours) we've only moved our engine forward about 1/8 of in inch so we have larger holes then we actually need which can afect the cooling of the ship.

This is the rear shield and it's importent that it Fits tight enough to close up the gaps

where it fits against the lower body panels or it to can affect how efficient the ships cooling system works.

END