Help! My sencond Plain, FX Explorer is completed. i have a qa. help me~

[starletzzang]

Hello
I made my second plane, ft explorer, following the simple cub and almost completed it.
I have a few questions.
1. I moved the tail wing forward about 10cm shorter because the center of gravity did not match well. It is known as a structure that can adjust the center of gravity by moving the tail wing. Did others do the same?

2. The center of gravity is not right, so I have only 3S 1100mah (weight: 120g) battery, so I added lead (weight: 5g x 10e) to match the basic 3S 2200mah weight. Wouldn't that be a problem for the flight?
A typical 2200mah weighs about 170g.

3. The total weight including the battery is about 950g.
The ft explorer page in the flitetest shop says the weight is 2.25LBS (1020g), is my weight correct?
How do other people get the weight of the aircraft fuselage?

4. Motor used a2212 1000kv, propeller used 8x4.5 Slow flyer. It weighs 950g, is it good performance?

Thank you, I have a lot of questions, thank you
Have a nice day

 

[CappyAmeric]

There are too many assumptions doing it like that. Where the CG is on your model, with your battery is what matters.

In setting CG, it is best to actually balance the model in your hands at the recommended center of gravity, rather than trying to attempt to replicate someone else’s model weight and suggested battery weights.

 

[CappyAmeric]

Also, by shortening the tail, you may have moved the CG, but at the expense of flight stability.

 

[JasonK]

note, if you change the distance between the horizontal stabilizer and the main wing, you also change the overall NP of the plane, which would then change the needed location of the CG. Moving the tail forward would move the needed CG location forward.

 

[JasonK]

the store page recommends a B pack [2212-1050kV] or C pack motor [2218-1180kV] with a 8 x 4.5 slow fly or 9 x 6 APC prop and shows a dry weight of 493 g.

- it appears that your motor/prop is in the recommended size, just on the low end. So if your airframe was around the same mass as the store page listed, I would expect it to fly ok, however it seems that your around 350g heaver then the the store page + recommenced battery would work out to [or +30-35%], so you might have issues or it might be ok, but your going to be closer to your limited then if your air-frame weight an appropriate amount.
- given your listed weight of 950g with the recommended battery weight of around 170g, it appears that you may have used 'heavy' foam that weighs about 2x that of the DTFB [Adam's ready board] / Flite Test Foam. This will make your airframe stronger, but will make it very hard to get your CG correct as most of the foam is behind the desired CG.

 

[JasonK]

The ft explorer page in the flitetest shop says the weight is 2.25LBS (1020g), is my weight correct?

no, it shows a dry weight of only 1.08 lbs (493 g) and adding the recommended battery [267g] only gets it to to 1.74 lbs (790 g).