Running an engine with the cowl off.

[Juliet Hotel]

I've towed a banner. Once. It was enough. Just picking it up requires some unusual maneuvering to avoid stalling.

The firewall is subject to flat-plate drag, and is easily calculated. A firewall with four square feet, at 70 mph, will have a drag of around 60 pounds. Some of that firewall is blanketed by the engine, but the engine itself offers plenty of parasite drag when out in the open.

If you towed a banner even once, you should know the name of the game is exposure time which is dependent on speed over the ground and slower is generally better. Parasitic drag increases with speed but banner guys don't like speed so parasitic drag is really their friend much more than their enemy. The bigger point is even loaded up with all that weight and all that drag, the plane still flies just fine.

 

[Dan Thomas]

If you towed a banner even once, you should know the name of the game is exposure time which is dependent on speed over the ground and slower is generally better. Parasitic drag increases with speed but banner guys don't like speed so parasitic drag is really their friend much more than their enemy. The bigger point is even loaded up with all that weight and all that drag, the plane still flies just fine.

The weight of the banner I towed wasn't much. The whole system is rather light, with the mast at the front being the heaviest part. It's weighted at the bottom to keep the banner upright. The drag was awesome, and getting it off the ground is the trickiest part. It's laid out in the direction opposite to the travel of the airplane to let the plane peel it off the ground rather than have to accelerate the whole thing at once. You have to approach at about 70 and just as the hook snags the loop you add full power and pull up failrly sharply to get the thing clear of the ground. Even at full power a Citabria (150 hp) won't pull it very fast.

 

[Juliet Hotel]

You have to approach at about 70 and just as the hook snags the loop you add full power and pull up failrly sharply to get the thing clear of the ground. Even at full power a Citabria (150 hp) won't pull it very fast.

A 150hp Citabria will pull letter banners and very small panels ok, but you need more wing and more HP to pull anything bigger. As far as the pickup goes, adding full power as the hook grabs the loop is a recipe for disaster IMO. I know some companies do this but I never did it that way and never taught it that way. Go to full throttle at the poles as the hook grabs and then find out the engine isn't responding for some reason and you're going to be in a world of hurt a few second later.

You really want to know that the engine is going to make power before you get the hook on the rope. Go to full power while you're still 3 or 4 seconds out from the poles. This reduces the workload at the pull up and it puts you in a much better position should the engine not respond when the throttle goes forward.