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

FT Tiny Trainer (Mighty Mini)

#63
daniel83, that looks like too much prop for a blue wonder... 8x3.8 is about max for the 1300kv version as long as you don't run wide open too long at a time (10-15 seconds at a time)
Is there some sort of rule of thumb for comparing props. He was going to use a 7060 which you said was too much but you suggested that a 8 x 3.8 would be all right. It makes sense that the 7060 has more pitch but does that negate the fact that the prop is longer?

I recently overproped my Blue Wonder (or similar clone). Haven't killed it yet but the 8x6SF on 3S was definitely too much and the motor overheated and drew 9A (too much).

A 9x4.7SF on 2S only drew 5.3A and the thrust as measured by holding it in my hand may have been acceptable.
I was finally happiest with a 7x5SF on 3S which drew 6.2A.
These were on my Bloody Wonder MKIII

Any knowledge will be absorbed,
Thanks, LooseBruce
 
#64
mrstamp, your cf2805 is rated for a 6x4 max for a 3cell... that 7x6 will make that motor go up in smoke in about 15 seconds


Nah, it's 1700kv I been using the same set up on my scaled down versa wing (30" wingspan) with well over 100 flights and motor never gets hot. There are different kv rating for the same cf2805 which all use different props. I will be using a gws7060 not a APC 7x6

Here is a link to the specs for the motor i am talking about. http://www.headsuphobby.com/Emax-CF2805-1700kv-Outrunner-Brushless-Motor-H-445.htm
 
Last edited:
#65
Is there some sort of rule of thumb for comparing props. He was going to use a 7060 which you said was too much but you suggested that a 8 x 3.8 would be all right. It makes sense that the 7060 has more pitch but does that negate the fact that the prop is longer?

I recently overproped my Blue Wonder (or similar clone). Haven't killed it yet but the 8x6SF on 3S was definitely too much and the motor overheated and drew 9A (too much).

A 9x4.7SF on 2S only drew 5.3A and the thrust as measured by holding it in my hand may have been acceptable.
I was finally happiest with a 7x5SF on 3S which drew 6.2A.
These were on my Bloody Wonder MKIII

Any knowledge will be absorbed,
Thanks, LooseBruce
I am using a 7x6 prop on a 3s with this motor, it is a great combo! I don't have a watt meter but the motor is never to warm. On the hobbyking site people reported using a 7x6 prop without exceeding 7.5A.
This motor is also working great on a 10x4.5 prop when using a 2s lipo, it's really nice for slow flights on the tiny trainer.
 
#67
I realized I made an error. I was asking about using 5g servos.

Okay, has anyone used 9g servos yet?

Check out Winglet's article and his 9g server placement recommendations: http://flitetest.com/articles/tiny-trainer-a-little-airplane-to-love

Excerpt from his article:

"Okay, just a little about my build. My airplane is basically completely stock. The most notable exception are the servos mounted on the outside of the fuselage near the tail, rather than inside the airplane under the wing. I would encourage everyone to make this simple modification to avoid adding a ton of weight to the tail to reach the correct CG. The TT builds extremely nose heavy. Also....Josh called for 5 gram servos. I went ahead and used 9's because I needed the weight. With a 850mah battery my CG is perfect. No weight added anywhere. "
 
#68
9G servos won't fit inside the fuselage anyway (tried it) if you're following the original plans, so you will have to relocate them to the back at the tail. There's really no choice there. But all is good - because as you say, reaching CG will be a breeze!
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#69
9G servos won't fit inside the fuselage anyway (tried it) if you're following the original plans, so you will have to relocate them to the back at the tail. There's really no choice there. But all is good - because as you say, reaching CG will be a breeze!
Dunno about that. I've got a pair of 9g in mine. Just needed to offset them from each other because they won't go in aligned. one is resting on the fuse floor, the other is almost at the top of the servo bay, but they happily coexist.

That and perhaps I skimped on the glue in the tail, but my powered version came up almost spot-on with a 2s500 under the pod. The glider nose need a bit of nose weight, but it also lacked a motor.
 
#70
Dunno about that. I've got a pair of 9g in mine. Just needed to offset them from each other because they won't go in aligned. one is resting on the fuse floor, the other is almost at the top of the servo bay, but they happily coexist.

That and perhaps I skimped on the glue in the tail, but my powered version came up almost spot-on with a 2s500 under the pod. The glider nose need a bit of nose weight, but it also lacked a motor.
Good point. I did at some point attempt to offset them but aborted due to how fiddly it was. Don't think I would ever have been able to glue them in precisely the right location - mainly thinking about the push rods and how they are z-bent on both ends. But, yeah, that could have been a non-issue if I had used linkage stoppers for the rudder/elevator control horns, instead of z-bending. It would however not change the fact that it's very very fiddly to try and glue the 9G servos offset in that tiny little space :)

Maybe I'm just not good enough at building yet.
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#71
"Good" is a relative term. You're almost certainly better than you were and unless you stop building, you will be even better some day ;)

Yeah, they were fiddly for the dry-fit, but mostly because they weren't tacked down. When it came time to install the servos, I cleared the bay, and installed only the lower one. Once the glue set, I disconnected from the servo tester and moved that servo horn as far aft as it would turn. Then I had plenty of space to install and center the other servo. (if you're not installing these servos with the servo tester plugged in, you're making it harder on yourself to center the surfaces).

. . . And if you think that's fiddly, I've got a hotliner with 4 9g servos, ESC, RX and lighting harness in about the same space as the TT's servo bay, with the front half of the bay covered by the wing mount :eek:

Suffice it to say, I hope I never have to swap out an aileron servo!
 
#72
I'm I the only one with a nose heavy tiny trainer, sport wing, A power set up, 370 mah 3s, 4 - 4.7 gram servos, 2 glue sticks. had to add 27 grams to tail to balance. Don't understand?
 

Torf

Senior Member
#73
I'm I the only one with a nose heavy tiny trainer, sport wing, A power set up, 370 mah 3s, 4 - 4.7 gram servos, 2 glue sticks. had to add 27 grams to tail to balance. Don't understand?
You aren't the only one. Many, if not most people have found it to be nose heavy.

Since the TT was my first plane ever, scratch-built or otherwise. I took the only solution I knew at the time and added 2 pennies to the tail in addition to the edge reinforcements.

Now that it has been a few months, the most common remedy is to relocate the servos to the tail. This goes a long way in ensuring good balance.

Other options include adjusting the wing a couple millimeters forward, and reinforcing the leading edges of the tail with hot glue.

Beefing up the tail skid helps too. After I added landing gear to my TT, I beefed up the tail skid with a piece of bbq skewer reinforced with a small piece of flag stick wire. Adding a tailwheel would also be an alternative.

If your flying fields tend to be a little more breezy, or you like to fly faster, don't be afraid to add a bit of weight. It will help it cut the wind better at the cost of a bit of efficiency.
 
#74
My TT made a patriotic appearance last evening at out family gathering. It was pulling three 30' streamers of red, white, and blue. One on each wing tip and the center one from the horizontal stabilizer. Due to some repairing that I need to do, I had to power it with my emax BL2215/25 spinning a 9x3.8SF on a 3s 1800 battery. I got a good 20 minutes of flying out of it. All of the extra drag kept the tail from yawing to much and really made for some very relaxing flying, especially since that was the first time I have flown in front of more than one or two other people.
 
#75
Second flight attempt was a winner today! I originally had the nose-heavy problem as many others do so I tried putting the battery on top of the wing. I don't know if it was just that or because I'm a newbie pilot, but I only got about 100 feet from me before it bit the dust. Broke the prop, but nothing else. I took it home and started researching mods to this awesome little airplane. I did the servo relocation to the tail and although it's not as pretty, it works really well! I also moved my massive clunky old receiver back under the rear wing stick. Now, she is balanced out beautifully and floats like a butterfly. It's a little squirrelly in the breeze, but I'll be doing a little reinforcement here and there so hopefully with the added weight, she'll cut through the wind a little better. Thanks Flite Test for getting me into airplanes! I love it!
 

Topper60

Junior Member
#80
I fly with trainer in 3 channels mode, very funny and easy to control, now the next step is to try 4 channels. It's a good plane for beginner.