u may fine that it remains " uneventful " . the bigger they get the less eventful they become. my 28"er is so uneventful it doesnt get the attention the smaller cousins get.

that being said it is the choice for our 1 size only streamer combat and the n/b pylon races.

chuck.

I finally made the flat wing version of the Underball. I just had the maiden flight this morning and it was awesome! It flew low and slow with the nose up about 20 degrees. It even did inside loops with the 4” prop. The pendulum effect does work for the rudder only turns. I can’t wait to fly it again and am already thing of making another. I’m sure I can shave off at least 20 grams on my next one.

Specs:
14”
AUW 85g
hextronik 5 gram brushless
GWS 4025 prop
1.9g HK-5320 servos
Batteries 2 Turnigy 1S 180mah ran in series

I like the motor (and mount) being protected. Does that little 5gm motor have enough thrust for unlimited vertical? Maybe I'll pick one up, or the 10gm version, at the NEAT fair.

I like it too.
I have a motor laying here not being used, also have some 5g servos........ Looks like I may have to make one to utilize the motor.
Do you have any up-down-right thrust built into it?
Is that just $Tree foam board without paper?
How small of an area can it be flown in? I have visions of flying a NutBall/underBall around my living room. The protected prop (and furniture) is a bonus.

Danford1

Originally Posted by Block

I like the motor (and mount) being protected. Does that little 5gm motor have enough thrust for unlimited vertical? Maybe I'll pick one up, or the 10gm version, at the NEAT fair.

I think if you get this plane under 60 grams and use the 5 gram motor with a gws 5x3 you should be ok. But you will definitively have unlimited verticals with a 10 gram motor and a 6x3 on 2s. My purpose was to make a simple plane that I can potentially fly indoors in the common room of my apartment building in the winter. It flies at walking pace right now but I want to make it go slower so I will put it on a diet.

Here are some thrust test results from the HK site for a 2S battery on the 5g motor:
GWS 3020 prop. 1 amp. ~38g thrust
GWS 3030 prop 1.2 amps, ~44g thrust
GWS 4025 prop 11,000 rpm, 1.4 amps, ~53gr thrust
GWS 4530 prop 9,000 rpm, 1.6 amps, ~62 gr thrust
GWS 4540 prop 1,9 amps, ~65g thrust
GWS 5030 prop 8,950 rpm, 1,83 amps, ~76g thrust

Hey Danford1,

I have the same vision of flying this plane in my living room… but for that I think I need to get it in the 40gram range.

Do you have any up-down-right thrust built into it?

The motor is mounted directly under the wing with no built in thrust angle. I correct for any drift by simply trimming it out.

Is that just $Tree foam board without paper?

Yes, the paper is peeled off and I re-laminating the foam with gift wrap covering also found at the dollar tree with the brand name Voila. The covering is added on both sides and makes the foam very stiff. In the next version, I plan on cutting out a DTF foam skeleton with covering on both sides to knock off 10 grams off the frame.

Originally Posted by vinnieg

Hey Danford1,

I have the same vision of flying this plane in my living room… but for that I think I need to get it in the 40gram range.

Do you have any up-down-right thrust built into it?

The motor is mounted directly under the wing with no built in thrust angle. I correct for any drift by simply trimming it out.

Is that just $Tree foam board without paper?

Yes, the paper is peeled off and I re-laminating the foam with gift wrap covering also found at the dollar tree with the brand name Voila. The covering is added on both sides and makes the foam very stiff. In the next version, I plan on cutting out a DTF foam skeleton with covering on both sides to knock off 10 grams off the frame.

Thank you. Of course I have more questions ;-)
Can you take a few pictures of the under side and lay a ruler on it for dimension references?
Can you explain more about the Voila covering and how you attached it?
Are those circles holes you cut in the foam or are they decorations drawn on it?
Did you measure the foam weight and compare the Voila weight for the same size specimen?
Thanks.
Danford1
PS I'll probably have more questions later...

Can you explain more about the Voila covering and how you attached it?

I use 3M-77 adhesive but it will melt the foam if applied directly. So first I lightly spray 3M-77 on the covering and let it sit. After a few minutes the glue is dry but still tacky. I stick the covering on to the foam by stretching it across. Finally I use a covering iron to reactivate the adhesive and shrink the covering. Just be careful with the iron as too much heat will causing warping.

Are those circles holes you cut in the foam or are they decorations drawn on it?

The circles are suppose to be lightening holes. I wish I had created more of them to add lightness to the entire frame.

Did you measure the foam weight and compare the Voila weight for the same size specimen?

I didn't compare the weight of the covering vs. that of the foam itself. But it is significantly lighter. Note that the covering also adds strength and stiffness to the frame.

requested pics attached.

I must say it has put a smile on my face to see you reproducing my Underball (thought flat) concept, you're going to love it .

I was amazed to see how well you've followed the lines

Work permitting I'll soon finish a Mark II version and do more videos with my existing one.

As you said..low and slow is what it does best, and ..for me.. not having to worry about damaging anything on it on crashes is a BIG bonus, this thing just bounces and keeps going, motor-prop always safe back there


One of the last videos with my son at the TX

Underball Fun (1 min 1 sec)

soon as I saw the underball, I knew I wanted one. It's was just a matter of where it sits on the build queue. I bet there are at least 5 others that have built one and not posted on this thread.

I flew it again this morning. I got a 6 minutes flight on my 2 X 180 mah 1S batteries. It was around 60 degrees at 7 am and totally calm in the field that I fly at on my way to work. It's so wonderful to watch it glide across the baseball field at such a slow pace about 5 feet off the ground. It was just me, the underball and a few geese watching. The geese and I were both smiling.

I tried flying it in the evening last night in some mild winds but didn't have much fun.

Originally Posted by vinnieg

soon as I saw the underball, I knew I wanted one. It's was just a matter of where it sits on the build queue. I bet there are at least 5 others that have built one and not posted on this thread.

I flew it again this morning. I got a 6 minutes flight on my 2 X 180 mah 1S batteries. It was around 60 degrees at 7 am and totally calm in the field that I fly at on my way to work. It's so wonderful to watch it glide across the baseball field at such a slow pace about 5 feet off the ground. It was just me, the underball and a few geese watching. The geese and I were both smiling.

I tried flying it in the evening last night in some mild winds but didn't have much fun.

yeah, it does like the calm conditions, that's why we flew it in a place we found that is very well sheltered by dense vegetation and trees, then is really good fun. See if you can post some video, I'd like to know and see how it compares being flat, what is it like it turning, can it recover from a very steep bank well?

The "unders" of the next Underball

I thought I'd add a bit of strength to the LE for extra toughness as I've managed to crack it there in a couple of places, easy to repair it was.

a bit of colour to it.. should be able to see this one well