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Help! FT simple cub, will it fly or not?

#1
Hi,
Recently I scratch builded the ft simple cub on a tight budget and it came out a little heavy. It weighs 508 grams (17.91 ounces or 1.1 pounds) without the battery and the recommended weight without the battery is 408 g (0.89 pounds). I have tried to fly it a couple of times without succes, it sort of lifted off and then instantly banking to the left plowed itself into the ground (there was no crosswind so that wasn't the reason).
I have never flew an rc plane before so i don't know if it's up to me or the general weight of the plane.
Here's my setup:
930 kv 2212 brushless motor(https://www.banggood.com/nl/XXD-221...html?rmmds=myorder&ID=517701&cur_warehouse=CN )
30 amp ESC (same link)
1300mah 3 cell battery (https://www.banggood.com/nl/TATTU-1...-p-1232345.html?rmmds=search&cur_warehouse=CN )
9g servos
flysky I6 receiver and transmitter (https://www.banggood.com/nl/FlySky-...7.html?rmmds=search&ID=42482&cur_warehouse=CN )
1060 prop
 
Last edited:

Hai-Lee

Old and Bold RC PILOT
#2
You have not mentioned the prop dia and pitch in your post but there are a few things you should know if your cub comes out too heavy.

Firstly it will fly and fly very well, but the speeds required for take off and landing will be a little higher.
You will need to keep the bird on the ground until it is travelling fast enough for the control surfaces to function adequately.
The fitting of a Slow Fly prop will reduce the tendency to veer left on take off if take off speed is low.
Adding some right thrust will also reduce the tendency to veer on take off.
To regain the low speed handling properties of the original design you can increase the incidence of the wing by placing a paddle-pop stick under the wing LE when you fit the wing. The increased incidence angle will actually increase the wings lift at take off and in level flight.

Mine was also a scratch build and it is flying very well and without needing repair after a full year of flying it. I use the wing incidence increase and the Slow fly prop. Also I do long take off runs and never have an issue with control.

Just what works for me!

Have fun!
 

messyhead

Well-known member
#3
Have you checked it's balanced properly and is all square?

Is it a 3 or 4 channel?

I've read that the Cub is actually quite tricky as a first time plane. If you're worried about wrecking it, you could build something like the Tiny Trainer to learn with.

Edit: @Hai-Lee said it all, listen to his wisdom more than mine
 
#4
You have not mentioned the prop dia and pitch in your post but there are a few things you should know if your cub comes out too heavy.

Firstly it will fly and fly very well, but the speeds required for take off and landing will be a little higher.
You will need to keep the bird on the ground until it is travelling fast enough for the control surfaces to function adequately.
The fitting of a Slow Fly prop will reduce the tendency to veer left on take off if take off speed is low.
Adding some right thrust will also reduce the tendency to veer on take off.
To regain the low speed handling properties of the original design you can increase the incidence of the wing by placing a paddle-pop stick under the wing LE when you fit the wing. The increased incidence angle will actually increase the wings lift at take off and in level flight.

Mine was also a scratch build and it is flying very well and without needing repair after a full year of flying it. I use the wing incidence increase and the Slow fly prop. Also I do long take off runs and never have an issue with control.

Just what works for me!

Have fun!
Thanks for the reply!
The motor packet came with a 1060 prop
I will try the paddle pop stick tomorrow!
 
#5
Have you checked it's balanced properly and is all square?

Is it a 3 or 4 channel?

I've read that the Cub is actually quite tricky as a first time plane. If you're worried about wrecking it, you could build something like the Tiny Trainer to learn with.

Edit: @Hai-Lee said it all, listen to his wisdom more than mine
It's a 3 channel like the build video recommended for beginner pilots. I had already tried building the tiny trainer but my battery and motor simply didn't fit, i have tried once flying it (by wonder i could balance it) but it flew more like a helicopter than a plane.
 

messyhead

Well-known member
#6
It's a 3 channel like the build video recommended for beginner pilots. I had already tried building the tiny trainer but my battery and motor simply didn't fit, i have tried once flying it (by wonder i could balance it) but it flew more like a helicopter than a plane.
Are you using the FT foam board?

I built a MUTTS which is a modified TT for heavier foam board, and easily fits a 3s battery. Maybe that would suit you better?

https://forum.flitetest.com/index.php?threads/my-mutts.57768/

I've just built the FT TT quick build kit for my son, and getting a 2s was still a tight fit.
 
#7
A slow fly prop helped me big time. I had the same issue. Also you don’t need full throttle to take off so I’d ease up to 70% throttle for takeoff. That will help control some of the torque issues and make it a little more tame
 

Hai-Lee

Old and Bold RC PILOT
#8
It's a 3 channel like the build video recommended for beginner pilots. I had already tried building the tiny trainer but my battery and motor simply didn't fit, i have tried once flying it (by wonder i could balance it) but it flew more like a helicopter than a plane.
OK as a three channel there is one additional balance requirement not mentioned anywhere and that is that the wings must each weigh the same for best operation. If one wing is heavier then it will want to fly lower to get the same lift as the lighter wing. This can introduce a yaw component or even a roll if the imbalance is too great. Hold the wings upside down and see if they balance around the join line. If one wing settles lower then add a small weight to the tip of the other wing until they balance.

As for the larger motor on a Tiny Trainer see the following thread;
https://forum.flitetest.com/index.php?threads/larger-power-pod-for-tiny-trainer.57826/

Have fun!
 

FDS

Well-known member
#9
Also if your wing is slightly warped it will roll in that direction. Without ailerons this can be very hard to trim out or correct. My Mini Guinea Wong was warped and it has to have a lot of aileron trim as a result.
If you want to resurrect the Tiny Trainer I have a motor recommendation that’s under $5 and flies great with a 6x4 APC prop. You should make a new power pod and a couple of spares if you want to fly that again.