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Pumpkin drop event

FT EZ Glider: Rubber Band Powered?

#1
Hey all, I never know where to stick questions like this so I hope it's okay posting it here. I do an FT-STEM based program here in Taiwan, and because the school doesn't have a big field, I'm always doing small planes with my class. The new FT EZ-Glider looks absolutely -perfect- for my situation! But this semester we've already done free-flight Sparrows, as well as the Sparrow's Egg Challenge from the FT-STEM curriculum.

What I'm hoping to find out, from those who helped develop the EZ Glider, is if it would be light enough to be able to be flown with a rubber band propeller. I have some Guillow's balsa kits but I feel they are too delicate for my 7th graders. If the EZ Glider could fly off a rubber band propeller, that would fit a great role in my curriculum! Any tips on this or anyone who has tried something similar?

Thanks for any feedback!
 

Headbang

Well-known member
#2
Yep, if doing as a rubber band free throw. Would take a few tosses to get the cg dialed in. The forces of a rubber power plane are a bit different then motor power. You will need to reinforce the rear holder for the band, I would suggest a few squares of ply or thick plastic with a hole for the dowel (not sure a bbq skewer is strong enough for a large rubber band)
Might be worth making a test stand to test different bands you have available. And of course you can tie bands together for a longer one(longer run time), or use multiple in parallel for more torque (faster, larger prop).
Sounds like a fun project. 7th graders should be able to figure it out no problems, kids are smarter these days. I was scratch building rubber powered gliders at a younger age.
 

buzzbomb

I know nothing!
#3
Might be worth making a test stand to test different bands you have available. And of course you can tie bands together for a longer one(longer run time), or use multiple in parallel for more torque (faster, larger prop).
That demonstration would make an awesome class in some basic physics, all by itself! (y)
 

FoamyDM

Building Fool-Flying Noob
#4
Hey all, I never know where to stick questions like this so I hope it's okay posting it here. I do an FT-STEM based program here in Taiwan, and because the school doesn't have a big field, I'm always doing small planes with my class. The new FT EZ-Glider looks absolutely -perfect- for my situation! But this semester we've already done free-flight Sparrows, as well as the Sparrow's Egg Challenge from the FT-STEM curriculum.

What I'm hoping to find out, from those who helped develop the EZ Glider, is if it would be light enough to be able to be flown with a rubber band propeller. I have some Guillow's balsa kits but I feel they are too delicate for my 7th graders. If the EZ Glider could fly off a rubber band propeller, that would fit a great role in my curriculum! Any tips on this or anyone who has tried something similar?

Thanks for any feedback!
I have been attempting the same thing with my cub scouts (K-5th grade). I haven't found anything yet, but I know it's out there somewhere. I will post here if I find it. does anyone know what they weight limit typically is on the rubber models?
 

buzzbomb

I know nothing!
#5
I have been attempting the same thing with my cub scouts (K-5th grade). I haven't found anything yet, but I know it's out there somewhere. I will post here if I find it. does anyone know what they weight limit typically is on the rubber models?
To my knowledge FliteTest doesn't make rubber band models. I'm relatively new here, so hopefully someone will chime in and tell me I'm wrong, but as far as I know, Casey is breaking new ground.

You've got to find the optimal size propellor and rubber band(s). Save weight where possible. Discover the dry and loaded weight of the plane, what sort of payload it might carry and discuss the implications of all the above. Just a part of it, in the classroom or as a quick project? As a grade-schooler it would be hard to get much cooler than that!
 

Headbang

Well-known member
#6
I have been attempting the same thing with my cub scouts (K-5th grade). I haven't found anything yet, but I know it's out there somewhere. I will post here if I find it. does anyone know what they weight limit typically is on the rubber models?
There is no wieght limit. I have done it with a bunch of #64 rubber bands, and also with surgical tubing. Done tiny fragile balsa, to 7ft all foam rubber powered planes. It comes down to how big you are willing to go, and what power you are willing to apply. Low wing loading is good for gliding, high wing loading needs more rubber and prop. Effectively most ft designs will work well. You are taking out the electronics, motor and battery. Saving around 100-700g of wieght depending on size. Larger will fly better. The ez glider is perfect. So is the tiny trainer. Cubs are always more challanging, no matter what you power them with. Explorer with the 3 channel wing would work, and it can be configured around a bit. It all comes down to what you are willing to do power wise. (Large rubber power is scary. Uncontrolled wound up prop waiting to eat you). Longer bands, larger props, glider like wing loading makes for a safe relaxing rubber power.
 
#7
Great feedback guys! Once the plans are released and my class builds some chuck-gliders, I'm going to challenge them to design a rubber-powered modification. I will update you all with any positive results we get!
 

Kendalf

Well-known member
#9
@Casey Any updates? Would love to hear how things went with your program! Incidentally, what city in Taiwan are you located in? I'm from Taiwan (though living in the US) and it's good to hear someone in this hobby from over there, even more so a fellow STEM teacher!
 
#10
@Casey Any updates? Would love to hear how things went with your program! Incidentally, what city in Taiwan are you located in? I'm from Taiwan (though living in the US) and it's good to hear someone in this hobby from over there, even more so a fellow STEM teacher!
I just put the plans in their hands today. We meet every Tuesday. I'm in Taichung. We are using a modified method of construction, because DTFB isn't available here. I've cut each of the four sides of the fuselage out separately, and we use 5mm paperless foam board and skin both sides with packing tape in the Experimental Airlines method. Then they're going to align the pieces, tape them in place, and hot glue.

I have some ideas about how to add a reinforced crossbeam in the tail to anchor the rubber band, but I'm keeping it to myself to see what the kids come up with. I'll try to get some pictures of the build process, if the kids will let me :)
 
#11
Well, long overdue update. My class pretty much settled on putting the rubber band around the already-existing vertical stabilizer tab, and simply poking a hole through the nose for the prop bearing. It worked reasonably well and gave the maximum rubber band length for the most turns.

But I did have one team decide that they wanted to make a twin prop version, so they got some drink bottles and , well, made the following: IMG_20190430_142553.jpg

It was heavy and didn't stay aloft very long, but I gave them bonus credit for ingenuity.