Banner tow engine cooling

[Skip Miller]

OK, a banner tow just went by. (Some form of Supercub dragging around the Geico critter, if you are curious.)

* High angle of attack
* High power setting
* Low airspeed

Do they have any problems keeping the engines cool? Is there some modification to a "normal" plane to adapt it to banner towing?

-Skip

 

[jesse]

My dad pulled banners for many years using Super Cubs. He said they had everything stripped off the airplane that they didn't need. They also completely removed the cowling from the airplanes.

This was in Florida during the summer--so they must take it pretty well.

 

[infotango]

OK, a banner tow just went by. (Some form of Supercub dragging around the Geico critter, if you are curious.)

* High angle of attack
* High power setting
* Low airspeed

Do they have any problems keeping the engines cool? Is there some modification to a "normal" plane to adapt it to banner towing?

-Skip

Skip the banner towers they use around Manhattan are super cubs that have no cowling.
They occasionally land at LDJ, and are operated by Viacom Advertising.

 

[JohnR]

At least one cowlingless Cub is used in Florida, and I've seen oil coolers poking out the side of a C150 cowling used for banners (yes, a 100 hp 150, no it was in a foreign country).

 

[Skip Miller]

Thanks for the replies. I did notice on a subsequent pass that the cowling does seem to be off.

Given the engineering brainpower it took to design the baffling to force the air through the cylinder fins with the cowl on, it seems possible that removing the cowling could hurt the cooling. Guess not.....

-Skip

 

[infotango]

Thanks for the replies. I did notice on a subsequent pass that the cowling does seem to be off.

Given the engineering brainpower it took to design the baffling to force the air through the cylinder fins with the cowl on, it seems possible that removing the cowling could hurt the cooling. Guess not.....

-Skip

I'm guessing that the ram air principals behind a cowling only help when the aircraft is actually going at some speed.
The planes that cross over Manhattan seem to only be going about 55kts.

 

[Joe Gremlin]

Given the engineering brainpower it took to design the baffling to force the air through the cylinder fins with the cowl on, it seems possible that removing the cowling could hurt the cooling. Guess not.....

You are absolutely correct. If you removed the cowl and did nothing more the engine would have absolutely horrible cooling characteristics. If you ever see a cowl-less banner plane up close, you'll notice that in place of cowl is a custom made plenum which sits on top of the engine and forces cooling at through the fins.

I assume the companies that do that, do it for the weight savings as those airplanes are usually stripped to the bone. No electrics, no interior panels, no side windows, etc.

However that's only one way to do it. The supercubs that I towed banners with had normal supercub cowls. The engine was usually 180hp and the planes all had full electrical systems and radios. For cooling we kept all the baffles in top shape and made sure they were as tight and as sealed as possible. Other than that, most of them had a second oil cooler which was usually mounted at the bottom of firewall hanging down below the cowl in the breeze. Most of them also had wingtip extentions.

I've also towed banners in a 180hp 172 which had no cooling mods at all and flew happily at normal engine temps all day at 60mph as long as the banners weren't too heavy.

 

[CJones]

I've also towed banners in a 180hp 172 which had no cooling mods at all and flew happily at normal engine temps all day at 60mph as long as the banners weren't too heavy.

Question: Do you pull banners at 60mph (or whatever slow speed it is) to limit damage to the banner itself, or are you basically running at normal cruise+ power and 60mph is all the speed you can get out of it? Just random curiosity.

 

[Joe Gremlin]

Question: Do you pull banners at 60mph (or whatever slow speed it is) to limit damage to the banner itself, or are you basically running at normal cruise+ power and 60mph is all the speed you can get out of it? Just random curiosity.

Flying banners is about advertising. That means you want your ad to be in front of people's eyes for as long as possible. That means you really want to go as slow as possible. I said 60mph earlier but that was really the upper speed limit. Any faster and the banner would really take a beating and come back in shreads. Often we fly much slower. In the 172 I think I was usually down around 50mph indicated. We'd stick a rag in the stall horn or it would drive you batty. In the supercub, 45mph indicated was typical if I had a tailwind (for a slower groundspeed) and 60mph was for when you had a headwind and were trying to keep on schedule. Everything else was somewhere in between the two.

I had a laugh a few months ago when I got checked out in a warrior. At one point the CFI said 'Ok let's see some slow flight. Full flaps and 60mph.' I laughed and said full flaps and 60mph was not what I considered slow flight. I asked if he wanted to see 50mph and no flaps instead but he wasn't interested.

 

[tonycondon]

joe what kind of CHTs were you facing during those ops? I run a supercub with 150 hp for glider towing. usually try to keep the CHTs below 400 degF. running wide open throttle and about 60-70 mph. not doing too bad so far this year but the heat of summer is coming...

 

[CJones]

Flying banners is about advertising. That means you want your ad to be in front of people's eyes for as long as possible. That means you really want to go as slow as possible. I said 60mph earlier but that was really the upper speed limit. Any faster and the banner would really take a beating and come back in shreads. Often we fly much slower. In the 172 I think I was usually down around 50mph indicated. We'd stick a rag in the stall horn or it would drive you batty. In the supercub, 45mph indicated was typical if I had a tailwind (for a slower groundspeed) and 60mph was for when you had a headwind and were trying to keep on schedule. Everything else was somewhere in between the two.

I had a laugh a few months ago when I got checked out in a warrior. At one point the CFI said 'Ok let's see some slow flight. Full flaps and 60mph.' I laughed and said full flaps and 60mph was not what I considered slow flight. I asked if he wanted to see 50mph and no flaps instead but he wasn't interested.

Interesting. I figured there was some "keep it out there as long as possible" type of stuff going on, but that philosophy would be fighting against "get as many different banners out as possible". ha

Just curious if the speed was limited by the banner or the airplane's performance. Now I know! I haven't been to Gulf Shores in so long that I can't remember if the planes were balls-to-the-wall or not.

Thanks!

 

[Joe Gremlin]

joe what kind of CHTs were you facing during those ops? I run a supercub with 150 hp for glider towing. usually try to keep the CHTs below 400 degF. running wide open throttle and about 60-70 mph. not doing too bad so far this year but the heat of summer is coming...

Interesting story. One of the Supercubs I used to fly had a CHT gauge which was inop and had been since the first time I got in the plane. I asked one of the mechanics about fixing it once. His reply was why would you want to to know what the CHTs were and what are you going to do about them if they're high. Good point I thought. I have no idea what they were but I suspect they were through the roof or close to it on some tows. In the banner biz replacing jugs is just part of doing business and we did it often. Most planes got at least one new jug a season but we flew a lot of very large, heavy stuff and we built the cost of beating the engines into the price of those tows.

 

[tonycondon]

kinda suspected that Joe.