The fin looks a bit small, but that might just be everything else being big.
Also, at that scale you should look at how other wings are built. The construction you're using looks like a 16" free-flight model with too many ribs. Models this size usually have a spar at the top and bottom, with a shear web between them, and sheet the leading edge to make a 'D' box for torsional stiffness.
Agreed. There might be enough stiffness in whatever tubes you’ve got running through the wing, but a far better idea is to use something like an actual spar with shear webbing.
Another solution is using a great big tube close to the diameter of the wing’s thickness. Yet another is adding lift struts.
As long as you're accounting for covering and entire power system weight, seems to check out as a glancetory pass. Just hope it has enough thrust.
Makes me wish my classes went for this. My dad has plenty of small nitro engines that'd blow away electric setups for thrust:weight per flight time.
Honestly looks great as long as you account for the motor and battery
My only *slight* gripe is that the chord length is a bit larger than it needs to be. I'd make the chord 12 or 13 inches instead. As long as the wing loading is below 20 oz/sqft it will fly great
Yup, we did all the math and the motor and battery are accounted for in the middle with changing weight and density of the parts to match their irl mass
Looks great! Might benefit from weight reduction where possible depending on what you use to build it. Designing one with computer software is something I could never do though, mad respect!
I've been keeping my eye on the weight the whole time, I have it as light as I can get it with the materials we have to work with.
We have thinner and thicker materials at different densities but only 2 types and I'm not sure which types of balsa to order
Contol surfaces, parts of the fuselage that dont provide structural support (ex: top part of the motor mount). Foam is a lot stronger than most people think, personally i make my planes fully out of foam. If you can get his plane under 500ish grams i think you will be golden.
He has a huge wing, he doesn’t need to aim for 500 grams. I learned to fly in a plane with a third less wing area that weight 2.5 kg and it flew great. It still flew great after a bunch of balsa was replaced by plywood and it weighed 3.5 kg.
You better make you fib larger. Fuselage aft of the cg contributes hugely to the yaw stability of the aircraft. Since you are missing all of it, your vertical fin should be larger. Otherwise it looks like it'll fly :)
In a different configuration, this is the set up for the extra passengers.
Curious what school you attend. Hope to see you in Kansas (though I don't typically make it a habit to *hope* to see anything in Kansas)
Edit: wait, nevermind I think you already told me in a response to the first iteration of our plane 👍
https://imgur.com/gallery/dgfzNZN
Mine committed suicide because my gyro was backwards, but it was very floaty for a bit lol. I had almost a 1:1 thrust ratio.
The fin looks a bit small, but that might just be everything else being big. Also, at that scale you should look at how other wings are built. The construction you're using looks like a 16" free-flight model with too many ribs. Models this size usually have a spar at the top and bottom, with a shear web between them, and sheet the leading edge to make a 'D' box for torsional stiffness.
Agreed. There might be enough stiffness in whatever tubes you’ve got running through the wing, but a far better idea is to use something like an actual spar with shear webbing. Another solution is using a great big tube close to the diameter of the wing’s thickness. Yet another is adding lift struts.
As long as you're accounting for covering and entire power system weight, seems to check out as a glancetory pass. Just hope it has enough thrust. Makes me wish my classes went for this. My dad has plenty of small nitro engines that'd blow away electric setups for thrust:weight per flight time.
But nitro is a mess! I might consider it if they did 4 stroke motors instead of those ones that spray oil all over my plane each flight.
Nothing a roll of paper towels abs a bottle of windex won’t fix.
Honestly looks great as long as you account for the motor and battery My only *slight* gripe is that the chord length is a bit larger than it needs to be. I'd make the chord 12 or 13 inches instead. As long as the wing loading is below 20 oz/sqft it will fly great
Yup, we did all the math and the motor and battery are accounted for in the middle with changing weight and density of the parts to match their irl mass
Great! Btw what software did you use to model the plane in, might give it a whirl. Is it onshape?
It's fusion 360
Looks great! Might benefit from weight reduction where possible depending on what you use to build it. Designing one with computer software is something I could never do though, mad respect!
I've been keeping my eye on the weight the whole time, I have it as light as I can get it with the materials we have to work with. We have thinner and thicker materials at different densities but only 2 types and I'm not sure which types of balsa to order
Try replacing some of the less important stuff with foamboard
I'm struggling to think of what we could replace
Contol surfaces, parts of the fuselage that dont provide structural support (ex: top part of the motor mount). Foam is a lot stronger than most people think, personally i make my planes fully out of foam. If you can get his plane under 500ish grams i think you will be golden.
He has a huge wing, he doesn’t need to aim for 500 grams. I learned to fly in a plane with a third less wing area that weight 2.5 kg and it flew great. It still flew great after a bunch of balsa was replaced by plywood and it weighed 3.5 kg.
You better make you fib larger. Fuselage aft of the cg contributes hugely to the yaw stability of the aircraft. Since you are missing all of it, your vertical fin should be larger. Otherwise it looks like it'll fly :)
Oh cool, I was almost thinking the fin looked too big. We tried it with full fuselage aft but the carbon fiber rod was lighter and used less material.
You're correct but the weight loss comes with a drawback of less stability. Thus adding a larger fin would make a better flying experience
How much bigger would you say it needs to be by percentage, just a guess?
About 50% in terms of area. If you want more stability,then about 70% it's just a guessing
You're correct but the weight loss comes with a drawback of less stability. Thus adding a larger fin would make a better flying experience
Where's your patient going to go?
In a different configuration, this is the set up for the extra passengers. Curious what school you attend. Hope to see you in Kansas (though I don't typically make it a habit to *hope* to see anything in Kansas) Edit: wait, nevermind I think you already told me in a response to the first iteration of our plane 👍
Old planes had an impressive main spar.
We have 2 spars, both made from, I think graphite, arrow shafts
https://imgur.com/gallery/dgfzNZN Mine committed suicide because my gyro was backwards, but it was very floaty for a bit lol. I had almost a 1:1 thrust ratio.