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New Guy with Tiny Trainer Flight Issues

#1
Good Day All,
I have been interested in model aviation for over 40 years. As a kid I built models but could not afford the radios and servos so never flew anything I built. This past winter I purchase a Hobby Zone Champ and learned to fly it pretty well. I think decided to build the Tiny Trainer as a way to step up to a more advanced plane. The build went ok and then I ran into a major problem on my maiden flight

The plane tended to bank severely to the left upon launch and would crash and cartwheel on the left wingtip. I read some of the forums...made sure my propeller was not backwards, calibrated the ESC, build a new nose sectition (first one was damaged in crash), made sure battery was fully charged. I tried launching it again. Same problem. Seems like this plane is very heavy and is not getting any lift. Before I rebuild the rest of the body...any suggestions?

From watching other peoples videos, I thought this plane would fly even if I wasnt that accurate on my build.

Thanks
Lee
 

rockyboy

Skill Collector
Mentor
#2
Welcome to the Forums!!

Can you post some pictures of your build? Especially a couple shots that are like a "3 views" - straight on from the top, side, and front. Also if you have the ability to get a weight that would be helpful too. The flight behavior you're talking about could be caused by the wings and horizontal stabilizer being tilted from each other and not parallel, or twist/warping too.

We'll help you get it figured out! :)
 

TexMechsRobot

Posted a thousand or more times
#3
Yep! We'll help you get this sorted out.

Other questions:

1. What motor/prop/battery are you using?
2. Where did you get your foam board?
 
#4
Welcome to the Forums!!

Can you post some pictures of your build? Especially a couple shots that are like a "3 views" - straight on from the top, side, and front. Also if you have the ability to get a weight that would be helpful too. The flight behavior you're talking about could be caused by the wings and horizontal stabilizer being tilted from each other and not parallel, or twist/warping too.

We'll help you get it figured out! :)
I will post pictures later when I get home. I think that you might have something when you mention twisting and warping. One of the main reasons I rebuild the nose was I felt it wasn't square to the back section of the plane
 
#5
Yep! We'll help you get this sorted out.

Other questions:

1. What motor/prop/battery are you using?
2. Where did you get your foam board?

I as far as prop and battery, I dont know. I purchased from the flite test store and used whatever they sent. Not smart enough yet to know all of the differences. The first foam board was the speed kit from FT. When I rebuilt the nose, I got the foam board from Dollar Tree.
 
#6
I think most mighty mini planes should bank right when tossed because their motors should be spinning counterclockwise. I had this problem on my mm sportster because the battery was really heavy and I was using too much throttle during take-off. To reduce the torque-roll effect, please make sure you're using the recommended battery and don't need tooooo much throttle to take-off.

Another big reason my sportster rolled and dived was because I had run it up so many times, the power pod was beginning to rip down due to the down-thrust. So you could try sticking a BB skewer or popsicle stick under the power pod to make sure it doesn't angle down too much. I did that on my tiny trainer and it flies like a sport plane now. :)

Hope this helped and added on to the previous posts.
 
#7
If you built it close to straight and close to design weight it will fly. Make sure the CG is where it is supposed to be. Place a ruler against the side of the rudder. Is it dead straight with the vertical stab? If so you may want to add a little right trim by adjusting the push rod, or sub-trim. Maybe 1/8" to the right of center, but it doesn't take much to turn the plane so don't over do it.

If you are launching it yourself you need a helper to launch it so you can concentrate on keeping it straight with the sticks instead of getting it in the air.
 

Hai-Lee

Old and Bold RC PILOT
#8
As you have stated that you did build it as a sporty plane I assume that the motor is rather powerful.

A powerful motor normally requires a revision of launching techniques. Launching at full thrust/throttle will give the maximum roll effects due to "P" factor and torque rollat a time when the aerodynamic control from the flight surfaces are minimal due to low speed. In flight the aerodynamic forces from the control surfaces are more than sufficient to overcome the inherent rolling forces due to the motor and propeller.

Ideally you should launch the plane at half throttle, (NO MORE), and allow the plane to build up speed before increasing the throttle and climbing. This period of launch flight is normally very short in the order of 10 to 20 ft only as it is the speed of the plane that will increase in this phase. Once up to speed fly as you wish!

The above is posted as a guide and assumes that your build is reasonably accurate and that you included the right thrust angle built into the original power pod plans.

Have fun!
 
#10
Thanks a lot. I was used to the Hobby Zone Champ which pretty much lifted out of my hand. The firs time I launched the TT, it banked and sank so I figure it needed more throttle because it was stalling. So I had way more than 1/2 throttle the 2nd and 3rd launch. I was trying to get it to move forward and gain lift. I guess now im nervous about giving it 1/2 throttle because this thing hits the ground hard. I will take your advice along with the others and see if this helps.

Question, how hard are you tossing this thing upon launch??
 

PsyBorg

Wake up! Time to fly!
#11
Tried to upload pics but the uploads kept failing. Is there a size limit?
Open the pictures in PAINT.. resize by percent until the size in the status bar is 1100 X ??? or less. It may take a few resets to get right but it works fine for posting here. I usually have 4k X 36??k pics and I shrink them down to 32% and they post perfectly. Then save and rename the pic. Once that is done it will post up nicely here.
 

Hai-Lee

Old and Bold RC PILOT
#12
Thanks a lot. I was used to the Hobby Zone Champ which pretty much lifted out of my hand. The firs time I launched the TT, it banked and sank so I figure it needed more throttle because it was stalling. So I had way more than 1/2 throttle the 2nd and 3rd launch. I was trying to get it to move forward and gain lift. I guess now im nervous about giving it 1/2 throttle because this thing hits the ground hard. I will take your advice along with the others and see if this helps.

Question, how hard are you tossing this thing upon launch??
I launch over head high to allow the plane a little more height, (and me more time to get both hands on the controls), with the nose only very slightly upwards, (just a few degrees).

As for the amount of force I use to launch it is hard to define but I am not a large person and almost underweight. If guessing I would say about the speed I would toss a ball to someone about 10 metres away.

As for its tendency to dive I would suggest that you check its CG yet again and do a few practice glides, (no motor power), to see if you can actually get it to "FLY" to the ground at a distant point, (10 metres?).

If it can do a wings level guide then you problem is entirely motor/thrust related, combined with a large touch of inexperience sadly. I started on the CHAMP and had the same problem when I first tried to transition to larger planes. Actually I am rebuilding my original Champ for my youngest son as I post this.

Have fun!
 
#13
Watch Josh's build video to get a good idea of how hard he launches. With half throttle you will need a javelin throw but with close to full, you can just nudge it. At least that is what I felt with my TT on a 800 mah setup.
 

nhk750

Aviation Enthusiast
#14
I have around 20 hours on my TT now with the stock FT power setup and a 700, 3s battery. I launch by full throttle and basically just letting it go left handed with my right hand on the aileron stick. I barely give it a little toss as it takes off like a rocket ship! The key is left hand launching, that way you have instant control on the ailerons and elevator. I see so many people right hand launch then grasp at trying to get control and that second or two can spell disaster. I actually hand launch larger planes the same way. 100% throttle, then you can back off the throttle when your left hand gets there.
 

Hai-Lee

Old and Bold RC PILOT
#15
I have around 20 hours on my TT now with the stock FT power setup and a 700, 3s battery. I launch by full throttle and basically just letting it go left handed with my right hand on the aileron stick. I barely give it a little toss as it takes off like a rocket ship! The key is left hand launching, that way you have instant control on the ailerons and elevator. I see so many people right hand launch then grasp at trying to get control and that second or two can spell disaster. I actually hand launch larger planes the same way. 100% throttle, then you can back off the throttle when your left hand gets there.
Sounds like you use mode 2! Most mode 1 users launch right handed. Rudder and elevator under control and throttle and aileron hand used to launch the model! Additionally not all aircraft have full span ailerons and so have no roll control at low speed except for a little rudder effect which is normally less than effective.

Sadly not everyone has well built, lightweight, and problem free models and many do not have their aircraft properly setup in the beginning. Whilst things like airspeed, torque roll and "P' factor do not seem to effect your aircraft and is something to be envied there are those who have such issues and for them the full power launch is a recipe for disaster.

If you could post the details of your build, and setup, it might provide a clue as to why someone else's build does not perform as well and the information you provide might also help them to fly their problem build.

For a beginner I still recommend to do the half power launch to increase airspeed and effectiveness of the flight controls prior to pushing through to full throttle so if torque roll or "P" factor are issues with the build the plane can still be launched successfully and not require a rebuild every trip to the field.

I do not wish to offend but rather to minimise the disheartening, and expensive, crashes the newbies suffer from at a time where they could easily become uncertain if flying models is the right thing for them!

Have fun!
 
#16
Open the pictures in PAINT.. resize by percent until the size in the status bar is 1100 X ??? or less. It may take a few resets to get right but it works fine for posting here. I usually have 4k X 36??k pics and I shrink them down to 32% and they post perfectly. Then save and rename the pic. Once that is done it will post up nicely here.
Thanks for the tip brother. That worked :)
 
#17
Welcome to the Forums!!

Can you post some pictures of your build? Especially a couple shots that are like a "3 views" - straight on from the top, side, and front. Also if you have the ability to get a weight that would be helpful too. The flight behavior you're talking about could be caused by the wings and horizontal stabilizer being tilted from each other and not parallel, or twist/warping too.

We'll help you get it figured out! :)
Alright. Finally able to get these pics uploaded

20170808_172422.jpg 20170808_172433 (1).jpg 20170808_172522 (1).jpg
 

rockyboy

Skill Collector
Mentor
#18
The build looks plenty straight enough - does the motor have any right thrust angle built into the motor mount or is it a straight flat motor mount?

And I know there are two very well thought out and solid recommendations in the thread for hand launching at both 100% and 50% throttle. In my experience, I like to do maiden hand launches at 75% and give them the hardest javelin style throw I can to get airspeed up quickly - and assuming she starts to reach for the sky I come back down on the power to 50% pretty soon. Once I get a feel for how the plane responds, I might reduce launch throttle, or if the plane is a bit under powered increase throttle. But I always try to hand launch with a hard toss.
 

nhk750

Aviation Enthusiast
#19
Hai-lee, I am mode 2, I forgot other areas use mode 1. Not sure I could use mode 1, my brain would probably melt trying that. For hand launching, having aileron and elevator control may make things easier in mode 2. My TT is scratch built and it is very accurate on cuts and bends with the 4 channel wing setup. I got lucky with this plane, it's a dream to fly.
 

PsyBorg

Wake up! Time to fly!
#20
Good Day All,
I have been interested in model aviation for over 40 years. As a kid I built models but could not afford the radios and servos so never flew anything I built. This past winter I purchase a Hobby Zone Champ and learned to fly it pretty well. I think decided to build the Tiny Trainer as a way to step up to a more advanced plane. The build went ok and then I ran into a major problem on my maiden flight

The plane tended to bank severely to the left upon launch and would crash and cartwheel on the left wingtip. I read some of the forums...made sure my propeller was not backwards, calibrated the ESC, build a new nose sectition (first one was damaged in crash), made sure battery was fully charged. I tried launching it again. Same problem. Seems like this plane is very heavy and is not getting any lift. Before I rebuild the rest of the body...any suggestions?

From watching other peoples videos, I thought this plane would fly even if I wasnt that accurate on my build.

Thanks
Lee
By chance did you install the power pod up side down? That would reverse the thrust angle. It also looks to me like the elevator and main wing are not as parallel as they could be. That one head on shot you posted looks like the right side of the wing is closer to the elevator then the left and that would produce the roll direction you are getting. Hard to tell if there is twisting in the fuse or either of wing surfaces are tilted.

Set the fuse on a flat table and measure the height of the elevator on both sides. That will tell you if that is off. Then keeping the fuse flat on the table see if the main wing has a lean. If it looks square that way as it can be hard to see by pictures then I would remove the main wing and try to balance it on a dowel down the seam in the center to see how much out of balance it may be from glue. I had that problem on my very first build. One side of the wing was heavier and induced a nasty roll over when tossed.