Solid rear mud flap falling apart, replace or remove?

[Dtjoint]

Searching through the archives I found about a decade old thread on whether the solid rear mud flap was a help or hurt in terms of throwing rocks onto the tow car and whether or not it impeded proper cooling of the Series 60 engine. At that time there seemed to be some controversy on both fronts. At that time a lot of the responders had the 8V engines. My 20 plus year old Country Coach logo mud flap is about to fall apart and I would like contemporary thinking on this subject. We have never experienced any cooling issues with it in place nor have we seen any evidence of it throwing rocks up onto our tow car. Ours is a 40' XL. The original mud flap installed by CC has worn off to nearly the bottom of the SS CC logo and the SS pieces are basically still in place only because of the wire ties that keep the side to side splits in the mud flap from tearing all the way off. So, please let me know your thinking. Thanks.

[Gil_J]

My short answer is that it shouldn't be there. If Prevost saw a need for it they would have installed it. Prevost installs rear tire flaps as well as a center flap between the drive wheels. So, what does the converter flap buy you?

In the plastic coach world these are often referred to advertisers flaps. When I bought my Prevost CC, that was one of the first things to go. There was no way I was leaving that on and go on the gravel roads to Alaska. Here's the common rationale on why to get rid of the advertiser's flap:
-- It is disruptive to the engineered air flow of the engine. By design of a S-60 powered coach, the air flow is from the radiator into the engine bay. Depending on year, that air exits primarily out the bottom of the engine bay. The advertiser flap pushes air upward, disrupting the engineered air flow.
-- Although most aren't driving on unimproved roads, gravel can get kicked up into the engine bay by the advertiser's flap.
-- It's a myth that on a Prevost the advertiser's flap helps keep debris from the towed vehicle. The Prevost flaps do that. Any debris that pass the Prevost flaps has more distance to fall to the road than debris kicked up by the advertiser's flap.
-- If the advertiser's flap is too close to the road it can create enough air turbulence to actually lift debris off the road.

To each their own. I won't run one.

[BoaterAl]

Years ago when I owned a Country Coach and followed the posts of 2 engineers. They installed test equipment to study the dynamics of air and pressure with and without the advertiser flap. Without any reservations the test results indicated negative pressure in the rear of RV when the advertiser flap was installed.
Gil's details states disruptive air flow doing zero assist while the RV travels down the road and no useful operational help having advertiser flap installed is supported.
FWIW

[Gil_J]

Al,

Was the point of negative pressure good or bad?

[BoaterAl]

Remember the posting..... "as bad" The other day saw the advertiser flag had angled back trying to plow air but the attachment chain allowed rubber flap to hit exhaust pipe burning the flap rubber to a crispy burn.

[Dtjoint]

Thanks for the observations. I removed the flap yesterday and will travel without it for a while to see if I can detect any difference in either rock throw or heat.

Jerry