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I have a weight problem.

#1
Outside the US us scratch builders have a very different foam board available. Among the differences is weight. Some have said it's as much as 30% heavier. My question is how can I compensate for the weight?

I've built a Tiny Trainer and I know it will fly because if I throw it it has a lovely gentle glide. It glides at about 15 degrees and gently settles on the ground. But to get it to fly I had to give it a lot of throttle and I think I have burnt out the ESC.

I'm assuming I need more speed to generate more lift but what is the best way to incrementally do that? I have a 6045 prop, a 2204 2300kv motor, a 12 Amp ESC and a 3S battery. I have ordered a 20Amp ESC but I'm wondering what else should I upgrade and to what. Can I get a different propeller, bigger, smaller, different pitch? Do I need a bigger motor? Or should just upgrade everything?
 

Hai-Lee

Old and Bold RC PILOT
Mentor
#3
I also do not have an easy access to the DTFB and use a heavier local material.

As for your TT you do not state which wing and what is the all up weight of your version. For my versions I use a 2205c 1400 kV motor with a 12A ESC and an 850mA 3S battery. The originally specified 2S power system was obviously underpowered as the landing speed and the flying speed were almost identical and control was poor.

Since fitting the motor Etc that I use I have NEVER had a motor or ESC failure and the speed is greatly improved and with the heavier FB the balance is almost perfect straight of the workbench. My combination can use upto 121 Watt and gives over 600 grams of thrust.
 
#4
I been trying to fly with the glider wing, no ailerons.
There doesn't seem to be that much difference in motor specs. What prop are you using?
 

Hai-Lee

Old and Bold RC PILOT
Mentor
#5
The motor I use can swing a prop from a 6x5 up to a 9x5SF. Because of my students ability to land poorly I need a large number of cheap props so my students get 6x5 props.

As mentioned the SF props really pull hard at take off and when throttling up from a near stall speed but otherwise are a little slower than the 6x5 which allows the motor to run at full RPM. The SF props of larger diameter do load the motor more.

Just had a thought! Some motors do require a clearance hole in the motor bulkhead to ensure that there is no binding of the motor shaft against the bulkhead. The motor I use does require a small clearance depression or it will run slowly and even overheat.
 

quorneng

Well-known member
#6
A 2204 2300kV motor will be working pretty hard (12A?) with a 3s and a 6x4.5 prop so you may well have burnt out the ESC. A 20A ESC should be ok but you are also operating pretty close to the limits of the motor.
What battery (capacity and C rating) are you using?
You can save weight by using a smaller capacity but higher C battery. It will need a bit less throttle but the flight times will be shorter as well.
Just up grading everything may not work that well. The total weight goes up and so does the power required to fly. At the same time it is quite likely its flying qualities will be degraded as well!