Design-Build-Fly Prototype Scratch Build

[Minton]

I'm the project manager for my school's Design Build Fly team this year. In the past few years, we either bit off more than we could chew or just had other issues getting a plane in the air, so this year I aimed to have a simple flying prototype by the end of week 3. We started last Friday and finished it very late on Sunday night (or Monday morning), and we plan to test fly it next Saturday. I personally spent about 24 hours on this thing so I'm both very excited and nervous to see it fly. I will post update photos from the test flight next weekend.

This year we are required to carry an electronic surveillance payload (weighted box) in mission 2, and a jamming antenna (PVC pipe) on the very tip of our wing in mission 3. On top of that, the entire aircraft must be portable and fit within a small carrying crate. We designed the wings to split in half, and the tail boom on the final aircraft will detach from the main fuselage to make the entire thing more compact.

 

[bisco]

looking good!

 

[Bo123]

nice

 

[quorneng]

Well done. That looks to be a competent design for the purpose.
Just out of interest what is proportion of the planes flying weight to the weighted box?
Carrying a payload creates both structural and aerodynamic problems, typically will it be strong enough and how much will it effect its flight characteristics.

 

[Minton]

Well done. That looks to be a competent design for the purpose.
Just out of interest what is proportion of the planes flying weight to the weighted box?
Carrying a payload creates both structural and aerodynamic problems, typically will it be strong enough and how much will it effect its flight characteristics.

The package is 3x3x6" and has to make up at least 30% of the aircraft's total weight. This prototype weighs almost exactly 6 lbs so the package would have to be at least 2.56 lbs. For the prototype, we plan to carry the package in a removable pod that sits directly under the CG so that no matter how much weight is added it won't affect the CG.

As soon as we start flying it we'll be able to gather some data for wing loading, but rctestflight on Youtube made a very similarly configured heavy lift plane and based on his max wing loading and wing area we might be able to have a max take-off weight of about 15 lbs. I tried to find some numbers for the thrust of the motors he was using but couldn't find anything. They look fairly small though so if we have more thrust than his plane, we could likely carry even more than that.

The structural integrity of the wing is something I'm a bit worried about. Our foam wing has 3 double layered, vertically oriented foam spars, and a 0.75" carbon fiber rod that goes through the middle and into the first 18" of each wing. With just the empty 6lbs plane, it passes the wing tip loading test with no problem. For the final plane, I plan to have a double-thick plywood spar and a 0.75 carbon fiber rod that both span the length of the wing. Since the wings MUST be built in two parts, I also want to add another short carbon rod that goes through the fuselage and into just the first 12" or so of each wing.

 

[skymaster]

I'm the project manager for my school's Design Build Fly team this year. In the past few years, we either bit off more than we could chew or just had other issues getting a plane in the air, so this year I aimed to have a simple flying prototype by the end of week 3. We started last Friday and finished it very late on Sunday night (or Monday morning), and we plan to test fly it next Saturday. I personally spent about 24 hours on this thing so I'm both very excited and nervous to see it fly. I will post update photos from the test flight next weekend.

This year we are required to carry an electronic surveillance payload (weighted box) in mission 2, and a jamming antenna (PVC pipe) on the very tip of our wing in mission 3. On top of that, the entire aircraft must be portable and fit within a small carrying crate. We designed the wings to split in half, and the tail boom on the final aircraft will detach from the main fuselage to make the entire thing more compact.
View attachment 230725 View attachment 230726 View attachment 230727 View attachment 230728 View attachment 230729 View attachment 230730 View attachment 230731

y the face covering

 

[Minton]

y the face covering

I like my privacy.

 

[skymaster]

I like my privacy.

Ok