Heat shielding

This is a heat shield that I couldn't understand for a long time

until it came up in a conversation on the phone one day with John Spurling.  We were talking about a heat rise in engine temps anomally we had on our ship one day.  When I mentioned to John that we didn't have this shield installed on our ship his reply was that if it wasn't sticking down at least 7 3/4 inches it wouldn't be doing anything anyways so it was irrelevant to my problem.

What happened to us was we were circling a friends home at 500 feet and our engine and oil temps went up.

John said that when I was performing that maneuver I was probably pulling alot of manifold pressure plus I had slowed down and didn't have as much air going through the ships forward scoops which is what most likely caused it. The trip to the place was also in 4kt down wind direction which I'd say didn't help anything.  After that, John asked if it cooled off after I got back into cruise in forward flight?  Well we were so close to the airpark that I headed back the moment I noticed the temps rising and it was so close by that almost the whole way there was pretty much if not all on a decent which also according to John what didn't help matters any.  He said the way the body on the ship is designed, that while we were decending the air flow off the body was burbling up into the radiator causing the cooling fan to not be as efficient.  According to John this is where the air dam, if we had one, would actually come into play.  What it does is redirect the the air coming across the bottom of the ship so it by passes the radiator opening so that it doesn't wreak havoc on the air flow trying to make its way out of the radiator.

John also said this is another thing that can play a part of the above anomally if you don't build your ship right.

This lower heat shield must fit close to the body or the air flow through the tub won't be very efficent. It will cause the ship to have higher operating temps if it doesn't so it needs to be fit as tightly as possible and along the bottom of the radiator cooling shroud and it should have a rubber seal along the complete if possible if you really wanna go the whole nine yards and do it right.  That part of our ship is as good as it gets except it doesn't have any rubber seals around the bottom of it.

Anyways I just can't imagine having this big 7 and 3/4 inch air plow
hanging down on our ship so we're going to leave it like it is.

John also told me long ago when I took my ship to him for its final rigging

that the engine upper exhaust heat shields were not necessary any more and that it was my option of course but if it was his ship he would do away with them.  He said that long ago the exhaust pipes used to made from steel and most people would have to replace them in as little as 75 hours and that some folks actually had holes blow through their pipes at the 180 degree bends.  These shields were designed to devert sparks away from the fuel tanks if that did indeed happen and other than that they didn't serve much of a purpose any more.  The reason for that is because RotorWay now uses stainless steel to make the pipes from which is alot better and has a very long life span.

All this is definitely something for folks to make up there own minds about before doing!

Another thing about fitting these shields if you choose to use them

is that you must be positive, particularly on the pilots side, that
they don't protrude past the mid section of the air frame
above them or they will infact wreak havoc with the ships main belts
when they do that oscillation thing they do.  What happens when the shields are to close to the belts is they will shred the main engine belts and you sure don't want that to happen to you.

These things are also high maintenance items
The shields themselves vibrate alot and I'm told are prone to cracking.

Another thing is they're a pain in the keester to work around while your performing other dutys on the ship.
I did get a taste of that while we had them on ours so that's something I certainly agree with lol.

You can see in these pictures this ship more then likely had some high temp issues.

END