Since I built my first FT Sparrow I've been in love with this design. So much so that I decided to have a go at upscaling. I decided on 175% so that I could get each wing onto one A1 sheet of foamboard. I used my own modified plans which adds some extra length to the nose for better CG. The foamboard we use here in Europe is heavier so you need that extra nose weight. I used mostly the 3mm variety. Say what you like about the euro foamboard, but its super stong. Saying that I did use 5mm for the tail.
It's a nice size with a wingspan of 1200mm. AUW with a 4s 4000 battery is 1.2kg See I'm in Ireland and wind is an issue, its almost always blowing some sort of breeze. I found my flying time was getting too limited waiting for that almost dead calm day so really the best solution is to build bigger.
I added some ply reinforcments at the bits that tend to get bashed and bent the most. i.e. In front of the wing (seen above) and also at the rear where the rubber band rod goes through. You cant see in the pics but theres a couple of squares of ply under there too.
Also at the rear I added some barbie skewers. I found that even in the regular sized sparrow the tail tended to crumple against the wing after a hard landing so the skewers do help a lot. I'd recommend these for even regular sized sparrows.
Last pic is the battery housing. It holds a 4S 4000 battery nice and tight with the velcro. Some extra foamboard padding in there too to help abosrb impacts on the battery.
You'll notice I havent talked about motor config. Well there's a story there cause I sorta messed up. I originally stuck in a NTM 28/26 1200kv and an 8x4 prop. Well with a 4S that combo kicks out 320W and the motor is only rated to 286W. Don't know why bells didn't go off in my head!! So last night it had its maiden and it flew beautifully. Lovely and stable, flew really nice scale looking loops and rolls and I got easily a good 10 minutes from the battery and when I checked the battery still had plenty left.
This evening I took it up and again it was flying beautifully intil the magic smoke came from the motor and it died. Thankfully I had plenty of altitude and it glided to a nice soft landing with no harm done except for my dead 28-26.
I also factored in an allowance for an extra bit of nose weight for a minature camera so I actually have some footage of this evenings entertainment and even the motor failure and glided landing.
In short I'm super happy with my super sparrow. A properly rated motor and she'll be back in the air.
If anyone wants to build one, I'd recommend simply printing out the plan at 175%, alternatively if your using euro foamboard, then it might be better to use my modified plan with the extra nose lenght and again print at 175%
It's a nice size with a wingspan of 1200mm. AUW with a 4s 4000 battery is 1.2kg See I'm in Ireland and wind is an issue, its almost always blowing some sort of breeze. I found my flying time was getting too limited waiting for that almost dead calm day so really the best solution is to build bigger.
I added some ply reinforcments at the bits that tend to get bashed and bent the most. i.e. In front of the wing (seen above) and also at the rear where the rubber band rod goes through. You cant see in the pics but theres a couple of squares of ply under there too.
Also at the rear I added some barbie skewers. I found that even in the regular sized sparrow the tail tended to crumple against the wing after a hard landing so the skewers do help a lot. I'd recommend these for even regular sized sparrows.
Last pic is the battery housing. It holds a 4S 4000 battery nice and tight with the velcro. Some extra foamboard padding in there too to help abosrb impacts on the battery.
You'll notice I havent talked about motor config. Well there's a story there cause I sorta messed up. I originally stuck in a NTM 28/26 1200kv and an 8x4 prop. Well with a 4S that combo kicks out 320W and the motor is only rated to 286W. Don't know why bells didn't go off in my head!! So last night it had its maiden and it flew beautifully. Lovely and stable, flew really nice scale looking loops and rolls and I got easily a good 10 minutes from the battery and when I checked the battery still had plenty left.
This evening I took it up and again it was flying beautifully intil the magic smoke came from the motor and it died. Thankfully I had plenty of altitude and it glided to a nice soft landing with no harm done except for my dead 28-26.
I also factored in an allowance for an extra bit of nose weight for a minature camera so I actually have some footage of this evenings entertainment and even the motor failure and glided landing.
In short I'm super happy with my super sparrow. A properly rated motor and she'll be back in the air.
If anyone wants to build one, I'd recommend simply printing out the plan at 175%, alternatively if your using euro foamboard, then it might be better to use my modified plan with the extra nose lenght and again print at 175%
