F53 chassis hanling in the wind
We have a, new to us, Winnebago Vista 26 on the F53 chassis. Have done the cheap handling fix, wheel alignment and tire pressure checks. On any kind of a windy day or truck passing the coach is a bear...
Forum Discussion
I have spent a ton of years as an Engineer in the Aircraft modification business and the same ton of years owning RVs. So I have given this problem lots of thoughts. here is my take:
Background:
1) Vehicles traveling down the road have a high pressure bow wake in the front and a low pressure area in the rear.
2) the magnitude of each of these is dependent on relative air speed of the vehicle (ground speed taking into account wind direction/magnitude) and vehicle aerodynamics (shape).
Problem
1) When one vehicle overtakes another these two areas interact causing forces on the vehicles. The magnitude of the forces applied to the vehicles has to do with the magnitude of the respective high and low pressure areas.
You cannot do anything about the other guy's vehicle. Although if you notice you probably have less push/pull from a truck with skirts and tails on them. As these mitigate the low pressure areas around the truck
That leaves what can you do to your vehicle.
Reduce the forces:
1) Here is where the airtabs, vorblades, etc. come in. They reduce the low pressure area behind your vehicle, thereby reduings the forces on your vehicle from a passing truck. Other than buying a Monaco Vesta or Holiday Ramble Trip (the only Class A I know of designed with wind tunnel testing) there is not much else to do on reducing the forces.
Reduce the effect of the forces on your vehicle.
1) So you have done what you can to make your vehicle more aerodynamic and you can't affect the other guy. So the last option to to reduce how your vehicle reacts to the forces.
2) What can be done here is very vehicle dependent. It depends on the aerodynamic shape of your coach (where are the forces being applied), your chassis, vehicle loading, etc. This is why we see what works for Coach A has little effect when the owner of Coach B tries it. hence so many threads that say "this solution worked great for me" and someone replies " it did nothing for me". The best option is to find folks with the same coach and find what has worked for them to limit the effect of the forces.
For me:
1) In previous RVs I had good luck with airtabs and vorblades. However, others have not.
2) I brought a Monaca Vesta. The engineer in me got tired of trying to mitigate the effect of the problem. The vesta was the only Class A I could find where engineers actually did wind tunnel testing to design a coach that mitigated the problem vice the effects. The result is amazing. it tracks like a train and I truly do not know when a truck is passing.
My $0.02 for what it is worth....
Background:
1) Vehicles traveling down the road have a high pressure bow wake in the front and a low pressure area in the rear.
2) the magnitude of each of these is dependent on relative air speed of the vehicle (ground speed taking into account wind direction/magnitude) and vehicle aerodynamics (shape).
Problem
1) When one vehicle overtakes another these two areas interact causing forces on the vehicles. The magnitude of the forces applied to the vehicles has to do with the magnitude of the respective high and low pressure areas.
You cannot do anything about the other guy's vehicle. Although if you notice you probably have less push/pull from a truck with skirts and tails on them. As these mitigate the low pressure areas around the truck
That leaves what can you do to your vehicle.
Reduce the forces:
1) Here is where the airtabs, vorblades, etc. come in. They reduce the low pressure area behind your vehicle, thereby reduings the forces on your vehicle from a passing truck. Other than buying a Monaco Vesta or Holiday Ramble Trip (the only Class A I know of designed with wind tunnel testing) there is not much else to do on reducing the forces.
Reduce the effect of the forces on your vehicle.
1) So you have done what you can to make your vehicle more aerodynamic and you can't affect the other guy. So the last option to to reduce how your vehicle reacts to the forces.
2) What can be done here is very vehicle dependent. It depends on the aerodynamic shape of your coach (where are the forces being applied), your chassis, vehicle loading, etc. This is why we see what works for Coach A has little effect when the owner of Coach B tries it. hence so many threads that say "this solution worked great for me" and someone replies " it did nothing for me". The best option is to find folks with the same coach and find what has worked for them to limit the effect of the forces.
For me:
1) In previous RVs I had good luck with airtabs and vorblades. However, others have not.
2) I brought a Monaca Vesta. The engineer in me got tired of trying to mitigate the effect of the problem. The vesta was the only Class A I could find where engineers actually did wind tunnel testing to design a coach that mitigated the problem vice the effects. The result is amazing. it tracks like a train and I truly do not know when a truck is passing.
My $0.02 for what it is worth....
