• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

Twin Boom Tiny Trainer (single pusher prop)

#22
The other bit is that with a 120° angle it decreases the vertical stabilization quite a bit. 110° gives you a ~1:2 vertical to horizontal area ratio while 120° gives you 1:3 which is a much bigger difference than it seems like it should be. One thing I liked about making my v-tail is that it was really easy to iterate on the tail though. Adjust the numbers, and fold a single piece of foam. :D
Side note, what expo settings do you usually use for v-tail planes?
 
#26
So after realising that I had a motor that could push this plane sitting in front of me the entire time, The Tiny Twin Boomer is ready for its Maiden (Re-Made-n) flight tomorrow I'm using an 1806 2280kv radial motor with a 6x4.5 prop. It seems to have plenty of go so hopefully it's enough until the 2212 2200kv motor arrives. IMG_20190620_221439-01.jpeg IMG_20190620_221426-01.jpeg
 
#27
Maiden flight! First attempt failed shortly after launch. Rudder control seemed way to sensitive and I think it was a little tail heavy, so I Decided to ditch them and just use ailerons and elevator and moved the battery forward. The tail booms popped off but no major damage. A quick hot glue repair and I went back out. Second attempt was much more successful, with a fairly steady flight in medium strength wind. Might turn down aileron throw and turn up elevator throw. Managed a tough but safe enough landing. So happy and surprised that it worked like it did. It glided really well too, with quite good slow speed characteristics, though the wind might have helped it. Next stop fpv. Screenshot_20190621-105039.png Will try get video of the launches up somewhere soon (y)
 
Last edited:
#29
Can confirm, plane needs more vertical stabilisation, still flies good, but it 'drifts' a little when making sharp turns like a car on a gravel road. Going to add some fins and see how that goes
 
#33
Went for very rushed flight very late this Arvo (low light and medium wind) with new tail, hard to say if it really helped, plane seemed to hard to control, could have been wind/light. Ended up dropping out of the sky after I flew behind a shed (I put it down to turbulent wind behind the shed). Tail is damaged but rest of plane is unharmed. I think I will ditch the v-tail and just go with an elevator-only tail with two fins like this IMG_20190623_121404.jpg
 
Last edited:
#34
That also looks cool. :D

If you ever do another v-tail though, do the math for the sizing/angle. Small changes can really make a big difference. If you didn't have enough vertical stabilization, I would really expect that the 120° angle was too much.
 

kilroy07

Well-known member
#35
That also looks cool. :D

If you ever do another v-tail though, do the math for the sizing/angle. Small changes can really make a big difference. If you didn't have enough vertical stabilization, I would really expect that the 120° angle was too much.
So, "ideally" would one want the angle to be 90? And I assume we are talking the angle between the two control surfaces, not the angle between say the control surface and the wing/ground plane?
(as I type that, it sounds like a dumb question... but I want to make sure anyway...) :rolleyes:

I've got a half baked project on my workbench, taking the $10 foam glider and turning it into this configuration, so any help making a "proper" A tail is MUCH appreciated!

Maybe @Hai-Lee can chime in, have you ever done an A tail?....
 
#36
That also looks cool. :D

If you ever do another v-tail though, do the math for the sizing/angle. Small changes can really make a big difference. If you didn't have enough vertical stabilization, I would really expect that the 120° angle was too much.
Yeah thats how it felt when flying it, like it wasn't getting enough vertical stability, sliding all over 5he place haha.
 
#39
I bet that addresses the Explorer's tendency to be tail heavy quite nicely!
Yeah, I bent the tail trying to slide it in (didn't fit properly) and then again when I dropped it on its tail. So not really thinking about the weight, I added strips of ply to each side of the tail, and it became ridiculously tail heavy, to the point where it needed a 5000mah 4s to balance it out. It only flew once with that much weight. Much happier now.
 
#40
So, "ideally" would one want the angle to be 90? And I assume we are talking the angle between the two control surfaces
Surprisingly no. So a lot of airplanes have approximately twice as much horizontal stabilizer area compared to the vertical. Not a hard rule, just a rule of thumb.

Using the formula from that website I linked earlier, with a 90° V, you'll have a 1:1 horizontal to vertical area ratio. Basically a plane with a huge vertical tail. At 110 the ratio is ~2.04:1, and I suppose that's why it's considered a good starting point for v-tails. At 120° you get a 3:1 ratio, and that's probably not a good mix unless you have a really short and stubby wing.