RC Banner Towing.
07-27-2008, 12:20 PM
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RC Banner Towing.
Assuming we use a large Cub as the tow plane...should the towed banner/flag...etc...be connected to the airframe at or near the CG, or at the tail?
What are the pros and cons.
Thanks.
What are the pros and cons.
Thanks.
07-27-2008, 01:59 PM
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RE: RC Banner Towing.
At the CG will only add the drag to the models performance (or is that subtract 
)
Adding that drag to the tail will dampen your control throws, think of a tail on a kite.
Adding at the CofG is the way to go. We have used a dowel passed through the airframe with good success.
)Adding that drag to the tail will dampen your control throws, think of a tail on a kite.
Adding at the CofG is the way to go. We have used a dowel passed through the airframe with good success.
07-27-2008, 02:19 PM
#3
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RE: RC Banner Towing.
I have seen a number of large Cubs used as tow planes. All worked best with the tow line attached at the top of the fuse right at the trailing edge of the wing. An A frame (an A shaped wire was mounted on the Stab with the lower ends of the A at the tips of the stab and the peak of the A at the top of the rudder to keep the tow line from wrecking thefin/rudder structure. This allowed the tow line to ride up over the rudder if things got cockeyed during the tow.
07-27-2008, 02:47 PM
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RE: RC Banner Towing.
Wonderful inputs here. I am thinking that since I will be towing a non-lifting device....a flag or banner, not another airplane....the connection may better be placed below the fuselage to assure no entanglement between the tow line and the tail feathers or tail wheel. I just cannot imagine a banner flying higher than the plane that is towing it.
07-27-2008, 03:33 PM
#5
RE: RC Banner Towing.
... but maybe the plane will fly a bit nose-up because it will fly slowly dragging that banner. 
Only thinking theoretically, but a banner won't move up and down and left and right like a sailplane, it's just always straightly behind the tug. So you shouldn't have any harm connecting the banner to the airplane's tail. It's even advantageous that it can't tangle, the small down force helps holding the airplane's nose up, and you don't need any special rudder authority either. After all you won't fly turns with rudder but with ailerons, and of course you'll use rudder only to counteract adverse yaw, won't you?
Did you already think about picking up the banner from ground or unreeling it in the air? The other way around: Did you ever see how it's done full-size?
Only thinking theoretically, but a banner won't move up and down and left and right like a sailplane, it's just always straightly behind the tug. So you shouldn't have any harm connecting the banner to the airplane's tail. It's even advantageous that it can't tangle, the small down force helps holding the airplane's nose up, and you don't need any special rudder authority either. After all you won't fly turns with rudder but with ailerons, and of course you'll use rudder only to counteract adverse yaw, won't you?
Did you already think about picking up the banner from ground or unreeling it in the air? The other way around: Did you ever see how it's done full-size?
07-27-2008, 03:59 PM
#6
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RE: RC Banner Towing.
I have towed banners for since the 60's and always hook yp to tail wheel. I make banner out of lace material and cut letter out of Felt cloth, I use a Dowel in the front of the bannner with some lead on bottom of dowel so banner will tow straight. The Navy used this system to tow target banners for other plane to shoot at them. Four different plane would use this banner for target practice, The plane bullets were dipped into different dye so they could see what plane had it the Target. I hope you can understand this BOB MOORE
07-27-2008, 05:52 PM
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RE: RC Banner Towing.
Well as it turns out, a good friend of mine is a professional banner tow pilot. He flys a 180 HP Cub, and we have talked at length of how he goes about doing the low fly by and pick-up. Full scale has many other issues to deal with that RC flyers are not so worried about. I intend to greatly simplify matters by hooking the banner up first, and towing it right off the ground. I will lay the banner well out ahead of the plane, and just off to the side so as not to roll over the tow line as I take off. The drag will come on more gradually that way as well.
Hooking up at the tail just seems to be wrong...because unless the banner is very small and light... it will definitely act as a steering device, attempting to defeat turns to some extent. My 20 foot banner, or 5 foot X 6 foot flag, will be a very large size and I know that will create a huge amount of drag. I am tending toward a near CG hook up point in order to lessen the effect of the banner trying to overwhelm the plane.
jim
Hooking up at the tail just seems to be wrong...because unless the banner is very small and light... it will definitely act as a steering device, attempting to defeat turns to some extent. My 20 foot banner, or 5 foot X 6 foot flag, will be a very large size and I know that will create a huge amount of drag. I am tending toward a near CG hook up point in order to lessen the effect of the banner trying to overwhelm the plane.
jim
07-28-2008, 07:08 AM
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RE: RC Banner Towing.
Two guys in our club tow banners and both hook to the bottom of the plane near the CG. They're configured as Bob Moore recommends, made of mesh with fabric letters, a few dowel stiffeners and small weights crimped along the bottom edge.
They take off with the banner furled, unroll it in flight and cut it loose to land.
Occasionally the banner comes out but doesn't unroll, just trails along at the end of the leader all rolled up, but usually a low pass to bump it on the ground will knock it open, which makes a better show!
They take off with the banner furled, unroll it in flight and cut it loose to land.
Occasionally the banner comes out but doesn't unroll, just trails along at the end of the leader all rolled up, but usually a low pass to bump it on the ground will knock it open, which makes a better show!
07-28-2008, 06:32 PM
#11
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RE: RC Banner Towing.
+Most of my banner towing has been with a Sig Kadet. I also used a smaller plane in the 60's. On my Kadet I have a bomb bay door on bottom of plane, and carry the banner aloft Also drop parachutes and can drop canddy or what ever. When I was in Navy I was assinged to Fighter Squdreon VF 111. When we went to El Centro. Ca for gunnnery practice. The Jets pulled the target Banners off the runway , with the tow line stretched out along runway. It has been since April 1954 since I was with VF 111 and I don't remember how the banner was attached to the jets but it was to bottom of the jet. They could drop it if they had problems . When they were ready to drop the banner the jet would drop it along runway.
I am an Airframe and Engine Mechanic and had in the past attached a tow rig on Super Cubs and Stinson L5 to tow Gliders and banners. The FAA approved paper work was to attach the tow hook up to the airframe at the tail wheel. I have never towed a Model glider up but have seen pictures and the tow hook up was on top of fusalage . Thes are just my Ideas . BOB MOORE
I am an Airframe and Engine Mechanic and had in the past attached a tow rig on Super Cubs and Stinson L5 to tow Gliders and banners. The FAA approved paper work was to attach the tow hook up to the airframe at the tail wheel. I have never towed a Model glider up but have seen pictures and the tow hook up was on top of fusalage . Thes are just my Ideas . BOB MOORE
07-28-2008, 06:54 PM
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RE: RC Banner Towing.
Hi Bob...You are correct. My full scale banner tow pilot buddy confirmed that they tow from the tail...and the reason for that is so that if they ever stall the plane, the drag pulling on the tail will help prevent the plane from rapidly going into a spin. A spin could get real messy with a tow line involved.
Towing by the tail does induce a lot of effort which will tend counter some of the turning movement of the airplane.
With the model, I don't anticipate any stall/spin activity, and of course I can dump the banner at any moment.
In full scale banner pick-up...the tow line is connected at the tail, and then is carried aloft with the hook end attached up near the wing struts, to be released when they do their approach. They dont want that hook to be able to reach the wing and prop in the event of a missed hook-up and then the hook snags the ground momentarily then slingshots forward doing some damage to whatever it may hit.
Obviously the tow hook line is quite short....less than one fuselage length. Thats how low they have to fly to hook up with the banner...and then immediately pull up hard. Yes, it is a dangerous job. These guys are a one man show. The pilot first sets up his ground poles which hold the banner tow line. Then he takes off, flys back down low and fast...drops the pick-up hook...hopefully he snags the banner line...then zooms skyward real quick.
And they don't make a lot of money either...mostly relatively new pilots just logging a lot of hours.
Towing by the tail does induce a lot of effort which will tend counter some of the turning movement of the airplane.
With the model, I don't anticipate any stall/spin activity, and of course I can dump the banner at any moment.
In full scale banner pick-up...the tow line is connected at the tail, and then is carried aloft with the hook end attached up near the wing struts, to be released when they do their approach. They dont want that hook to be able to reach the wing and prop in the event of a missed hook-up and then the hook snags the ground momentarily then slingshots forward doing some damage to whatever it may hit.
Obviously the tow hook line is quite short....less than one fuselage length. Thats how low they have to fly to hook up with the banner...and then immediately pull up hard. Yes, it is a dangerous job. These guys are a one man show. The pilot first sets up his ground poles which hold the banner tow line. Then he takes off, flys back down low and fast...drops the pick-up hook...hopefully he snags the banner line...then zooms skyward real quick.
And they don't make a lot of money either...mostly relatively new pilots just logging a lot of hours.
08-05-2008, 02:31 PM
#13
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RE: RC Banner Towing.
I have towed signs and banners.
I hooked the towline to a release at the tail.
I found very few drawbacks to flight with the banner on.
Pitch was slow, but the plane turned fine. Rolls and inverted were also OK.
Plus side , all adverse yaw was eliminated by the drag of the banner.
I've towed with Aeromasters and Sportmasters and even a Falcon 56 all without problems.
I hooked the towline to a release at the tail.
I found very few drawbacks to flight with the banner on.
Pitch was slow, but the plane turned fine. Rolls and inverted were also OK.
Plus side , all adverse yaw was eliminated by the drag of the banner.
I've towed with Aeromasters and Sportmasters and even a Falcon 56 all without problems.
09-03-2010, 11:32 AM
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RE: RC Banner Towing.
Hello guys, with what minimum size model we should start with? Banner should be a decent size. Need it for an airshow being arranged for kids.. Regards, Sunny.
09-03-2010, 04:28 PM
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RE: RC Banner Towing.
A buddy burned up a 46AX that was a couple of months old trying to haul a long streamer at top speed. Two things needed to be changed to make it work.
Trying to go flat out isn't the best choice. Using a flatter pitch prop than the one he'd chosen for daily flying would have helped too.
The bigger you go, the less impact your banner will have.
I fly a number of warbirds that were designed for 60 size glow. I use 90s to swing a bigger 3-blade. (They are the same size and almost the same weight.) The 90s have half-again more horsepower than the 60s. If I had to choose an engine to pull a banner, I'd pick the 90 over the 60. And I would bet on the 90 being able to do the job.
Trying to go flat out isn't the best choice. Using a flatter pitch prop than the one he'd chosen for daily flying would have helped too.
The bigger you go, the less impact your banner will have.
I fly a number of warbirds that were designed for 60 size glow. I use 90s to swing a bigger 3-blade. (They are the same size and almost the same weight.) The 90s have half-again more horsepower than the 60s. If I had to choose an engine to pull a banner, I'd pick the 90 over the 60. And I would bet on the 90 being able to do the job.
09-03-2010, 07:59 PM
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RE: RC Banner Towing.
In the T-45, we towed a gunnery banner that was attached using the tailhook uplock mechanism. Lowering the tailhook would release the banner. Flying qualities weren't noticeably changed, although you could definitely feel fore-and-aft surging as the tow cable stretched back and forth. The fuel flow was also quite a bit higher with the banner attached.
09-03-2010, 11:47 PM
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RE: RC Banner Towing.
da rock & shoe: Thanks for the help,
da rock, how about using a world models 1/5 3 Cub with 75ax OR 95ax? However Inoticed that model build is not very very strong for making it light weight! How storng should be a model to pull a banner? If it isnt it, then should I go for the ESMCessna 185? Though that will cost me on much higer notes..
Regards, Sunny.
da rock, how about using a world models 1/5 3 Cub with 75ax OR 95ax? However Inoticed that model build is not very very strong for making it light weight! How storng should be a model to pull a banner? If it isnt it, then should I go for the ESMCessna 185? Though that will cost me on much higer notes..
Regards, Sunny.
09-03-2010, 11:55 PM
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RE: RC Banner Towing.
All the engine knewthat he was spinning and spinning really hard BUT not going forward with thespeed he was supposed toSO it decided to heat up &eventually burned up 
09-04-2010, 05:34 AM
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RE: RC Banner Towing.
ORIGINAL: Bozarth
How did the engine know?
Kurt
ORIGINAL: da Rock
A buddy burned up a 46AX that was a couple of months old trying to haul a long streamer at top speed.
A buddy burned up a 46AX that was a couple of months old trying to haul a long streamer at top speed.
Kurt
Also, the load on an engine comes from two things. First thing is the drag of the airplane and whatever is attached to it. Second thing is the prop.
When the drag increased greatly with the addition of the banner/streamer, the speed is slowed greatly. Not only will the cooling get screwed, but the prop now winds up operating at a higher AngleOfAttack. AOA of a prop is a function of it's airspeed. The faster it goes, the flatter the AOA. The flatter the AOA, the less the load. Props unload in the air, you can hear it. They're unloading as they pickup speed in flight. Stop them from picking up speed and they don't unload. The engine stays under that load that's usually "unloaded". Put a flatter pitch or smaller diameter prop on, and it'll have a chance to unload. It'll also have an easier time pulling the new load.
No, the engine didn't know. It just ran much hotter than before. It started predetonating thanks to the extra heat and wound up melting the inside of the head and the top of the piston.
What can the modeler do? He had originally tried a couple of different props to see which flew the plane best. He could have tried that again when he altered "the plane" with the streamer to see what prop would permit the engine to deal with it's new work load.
09-04-2010, 06:53 AM
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RE: RC Banner Towing.
da rock, how about using a world models 1/5 3 Cub with 75ax OR 95ax? However I noticed that model build is not very very strong for making it light weight! How storng should be a model to pull a banner? If it isnt it, then should I go for the ESM Cessna 185? Though that will cost me on much higer notes..
Regards, Sunny.
Regards, Sunny.
09-04-2010, 09:19 AM
#23
Senior Member
RE: RC Banner Towing.
If you go with the WM Cub, the 95AX would certainly be the better choice for banner pulling. That Cub certainly would not need the 95AX for normal operation, but your consideration is more for the banner than the airplane.
Matter of fact, the banner size is going to be decided almost exclusively by the engine size and excess power, not by your airplane size alone. The idea that a bigger plane is better is based mostly on the power usually available to models by their size. The more power (ignoring how much is excess) available, the less effect a fixed load will impose. Of course, if you combine an oversized engine with any size model, you'll have excess power to use for other things.
For a couple of years, a number of us towed and piggy-backed gliders. Every tow plane that was used more than once or twice wound up having it's engine up-sized. We tried different props on a couple before up-sizing and they almost always obviously helped. The up-sizing helped of course, and selecting towing props for them also helped even more.
Matter of fact, the banner size is going to be decided almost exclusively by the engine size and excess power, not by your airplane size alone. The idea that a bigger plane is better is based mostly on the power usually available to models by their size. The more power (ignoring how much is excess) available, the less effect a fixed load will impose. Of course, if you combine an oversized engine with any size model, you'll have excess power to use for other things.
For a couple of years, a number of us towed and piggy-backed gliders. Every tow plane that was used more than once or twice wound up having it's engine up-sized. We tried different props on a couple before up-sizing and they almost always obviously helped. The up-sizing helped of course, and selecting towing props for them also helped even more.
09-04-2010, 12:46 PM
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RE: RC Banner Towing.
The banner is also going to hold back the model's airspeed so a model that flies well at a slower speed will retain more of it's control and have less risk of unexpected stalls. So go with the lighter model.
For towing you will not want to hook the banner at the tail like they do with full size banner and glider towing planes. Our models do not have the control power to pull the big drag loads like the full size ones do. Instead use the tow line attached up on the upper fuselage deck just behind the wing like model glider tow planes use. But you will want to prevent the tow line from getting caught up around the tail controls in near the fuselage. To avoid this the glider tow planes use lines arranged around the tail surfaces that look much like the old tail bracing wires on full sized airplanes. You'll want to pass these guard lines through the horizontal and vertical tails at about the 3/4 span point. And on the bottom the line should just go to the lowest fuselage point.
For towing you will not want to hook the banner at the tail like they do with full size banner and glider towing planes. Our models do not have the control power to pull the big drag loads like the full size ones do. Instead use the tow line attached up on the upper fuselage deck just behind the wing like model glider tow planes use. But you will want to prevent the tow line from getting caught up around the tail controls in near the fuselage. To avoid this the glider tow planes use lines arranged around the tail surfaces that look much like the old tail bracing wires on full sized airplanes. You'll want to pass these guard lines through the horizontal and vertical tails at about the 3/4 span point. And on the bottom the line should just go to the lowest fuselage point.
09-04-2010, 11:50 PM
#25
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RE: RC Banner Towing.
ORIGINAL: da Rock
Engines don't know anything. They just do what you make them do. He made it try to fly fast with a lot more load than normal. With the extra drag, it got a lot less cooling as the cooling air moved over it a lot slower than normal.
Also, the load on an engine comes from two things. First thing is the drag of the airplane and whatever is attached to it. Second thing is the prop.
When the drag increased greatly with the addition of the banner/streamer, the speed is slowed greatly. Not only will the cooling get screwed, but the prop now winds up operating at a higher AngleOfAttack. AOA of a prop is a function of it's airspeed. The faster it goes, the flatter the AOA. The flatter the AOA, the less the load. Props unload in the air, you can hear it. They're unloading as they pickup speed in flight. Stop them from picking up speed and they don't unload. The engine stays under that load that's usually ''unloaded''. Put a flatter pitch or smaller diameter prop on, and it'll have a chance to unload. It'll also have an easier time pulling the new load.
No, the engine didn't know. It just ran much hotter than before. It started predetonating thanks to the extra heat and wound up melting the inside of the head and the top of the piston.
What can the modeler do? He had originally tried a couple of different props to see which flew the plane best. He could have tried that again when he altered ''the plane'' with the streamer to see what prop would permit the engine to deal with it's new work load.
ORIGINAL: Bozarth
How did the engine know?
Kurt
ORIGINAL: da Rock
A buddy burned up a 46AX that was a couple of months old trying to haul a long streamer at top speed.
A buddy burned up a 46AX that was a couple of months old trying to haul a long streamer at top speed.
Kurt
Also, the load on an engine comes from two things. First thing is the drag of the airplane and whatever is attached to it. Second thing is the prop.
When the drag increased greatly with the addition of the banner/streamer, the speed is slowed greatly. Not only will the cooling get screwed, but the prop now winds up operating at a higher AngleOfAttack. AOA of a prop is a function of it's airspeed. The faster it goes, the flatter the AOA. The flatter the AOA, the less the load. Props unload in the air, you can hear it. They're unloading as they pickup speed in flight. Stop them from picking up speed and they don't unload. The engine stays under that load that's usually ''unloaded''. Put a flatter pitch or smaller diameter prop on, and it'll have a chance to unload. It'll also have an easier time pulling the new load.
No, the engine didn't know. It just ran much hotter than before. It started predetonating thanks to the extra heat and wound up melting the inside of the head and the top of the piston.
What can the modeler do? He had originally tried a couple of different props to see which flew the plane best. He could have tried that again when he altered ''the plane'' with the streamer to see what prop would permit the engine to deal with it's new work load.
Kurt