FT Bushwacker CG problems

SSgt Duramax

Junior Member
I think it looks better with the longer nose.

I have started this thing when I design planes to make sure the nose is long, and maybe longer than it needs to be. It is always easy to scoot the battery back. Squeezing it forward millimeters away from the prop is no fun and usually doesn't fix the issue.

I also echo the sentiments of not using hot glue on the tail, I haven't used it back there in quite a while. I have typically opted for wood glue.

Also, while we do focus a ton on the tail (and for good reason) I have learned in my plane 3D printing time that wing weight behind the spar/balance mark matters a ton too. I kept wondering why one of my planes was so dang tail heavy, did some quick math and figured that my battery should have easily been able to balance the tail weight out, and then I picked up the wing, which was probably the heaviest part of the plane, and it was super tail heavy. Now I know the moment around the center of gravity is less, but still it adds up, especially if you are glooping your wing with hot glue when you put it together. Something worth thinking about when you are considering reinforcement placement, servo placement, or wing construction techniques/materials in general. While it may not be as huge as a heavily braced 3D printed wing, it still counts and is worth considering.

I do not have a 3D printer yet, but plan on buying one in the next month. What printer do you have or would recommend that won't break the bank but is still easy to use without much problems?
Yes, please send me the STl files for all that you mentioned including the Tricycle gear. Thank you!!!
If you have any sweet ideas for a parachute drop that would be great too.
I think once I get a calm day I might actually get this Bushwacker to stay in the air. I have launched it a couple of times but crashed soon after. One of these times I will get it back on the ground safely. Ha Ha.

I think a lot of us on here use Ender 3s, pretty much because it is a widely used and very well supported budget printer with readily available parts and support. There are absolutely better printers, there are cheaper printers, and there are probably arguably better ones for the money, but it is kind of like the easy button for printers under $300 bucks for people that have never done 3D printing before and aren't sure if they want to dump a huge investment into one. It is to printers as the FS i6 is to radios. Once you outgrow it you will know what you want.

There is no right answer, and folks will have varying opinions, and a lot of your success will come from your willingness to fine tune and learn about the thing, which could really be said about any printer. Some will be harder or less capable than others. The Ender is just the right amount of easiness and right amount of capability for the right price for a beginner. But I am no pro.
 
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I think it looks better with the longer nose.

I have started this thing when I design planes to make sure the nose is long, and maybe longer than it needs to be. It is always easy to scoot the battery back. Squeezing it forward millimeters away from the prop is no fun and usually doesn't fix the issue.
Yeah one of my most bothersome guessing games is designing enough room for the battery. I have two planes on my list that I can't get through the design phase because I can't guess how far forward I'll need to get the battery, and the longer the space I make, the more it detracts from the design.
ccf_burnelli_cby_3-32770.jpg
 

SSgt Duramax

Junior Member
Yeah one of my most bothersome guessing games is designing enough room for the battery. I have two planes on my list that I can't get through the design phase because I can't guess how far forward I'll need to get the battery, and the longer the space I make, the more it detracts from the design.
View attachment 223998
Gee wiz, that is tough. You might have to do like me and slop together a prototype to see how it balances out, even though I realize that is against your nature.

My first knee jerk thought is to compensate with bigger motors, but then that means a bigger battery. You might be able to run 2 smaller batteries in parallel to get it as far forward as possible.

Then I thought that you could make it really big and light, but then I remembered size is a thing for you. You could do some sort of foam tissue hybrid on the rear.

Which brings up the last resort which is incrementally increasing the length infront of the CG until you achieve desired weight.
 
Gee wiz, that is tough. You might have to do like me and slop together a prototype to see how it balances out, even though I realize that is against your nature.

My first knee jerk thought is to compensate with bigger motors, but then that means a bigger battery. You might be able to run 2 smaller batteries in parallel to get it as far forward as possible.

Then I thought that you could make it really big and light, but then I remembered size is a thing for you. You could do some sort of foam tissue hybrid on the rear.

Which brings up the last resort which is incrementally increasing the length infront of the CG until you achieve desired weight.
Yup. All of the above.

I've got the drawings roughed out - until I got too frustrated and shifted to another design.
I've been meaning to do a "moment arm" survey of a couple planes I already built, to develop some sort of comparison of weights and distance to CG for motors, battery and whatever else I can figure, but it the end that results in a starting ballpark rough idea at best.

For me the only obvious solution is to lengthen the central fuselage a bit. This is the perfect example of a little bit will be ok, much more will start to ruin the effect. If only I knew how much, without having to build the thing twice.

I could also push the motors forward a little bit. I could reshape the outer wings a little farther back.

If I were really smart I might figure out how to easily extend the nose of the thing... :unsure: As long as there's clearance around the props...

And a voice keeps saying "Well how awful would it be, really, to have a longer nose?" The other voice says "What does this have to do with the FT Bushwacker??!"

grumble
 

ColoFlyer

Active member
I do not have a 3D printer yet, but plan on buying one in the next month. What printer do you have or would recommend that won't break the bank but is still easy to use without much problems?

I will try to send them tomorrow, but If I don't get a chance it will be a couple weeks due to us being out of town.
In the mean time, Read through this thread
https://forum.flitetest.com/index.php?threads/ender-3-v2-for-beginners.69443/

Also I believe that SSgt Duramax mentions the Ender 3-S1 in his post above, this is the newer version of the Ender 3V2 and already has most all the upgrades built in, making it a better choice.
 
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dap35

Elite member
To overcome tail heavies, I add length to the nose. I slide the power pod until I get the plane to balance. This estimates the length to add, I generally round it up to an even number. Then I cut the nose off and add in the foam needed. A simple but joint is all that is necessary to glue the nose back on.
When I rebuilt my Simple Stick, I added 3" to the nose and now it flies perfectly without any weight.