weight

gary baker

New member
g'day from Australia, friends!
I am building my first (scrach built) foam board aircraft! I am almost ready, but I'm worried about the weight... the fuselage is 49 cm long (about 20") and the wing is 73 cm x 16 cm (about 2'5" x 6.5")
The weight (with everything on board) is now 385 gm (13.59 ounces) which seems heavy! the motor is a brushless 2700kv.. what are my chances of seeing this thing actually airborne?
PS the only foam board I can find here in Oz seems too heavy... for other Australian readers, I got it from Office Works..
 

Foamforce

Well-known member
That’s similar in dimensions to the mini Pietenpol, which has an all up weight of 277g. Your weight included the battery, right?

So yours is heavy and that will make it a little more difficult to fly, but it still ought to fly. One thing though, 2700kv doesn’t tell us how powerful the motor is. Do you know what size it is? E.g., 2205?
 

Foamforce

Well-known member
I think that’s a pretty big motor for that plane. It will fly, but you’ll have to go fast to keep it in the air. Let ‘er rip!
 

Bo123

Elite member
g'day from Australia, friends!
I am building my first (scrach built) foam board aircraft! I am almost ready, but I'm worried about the weight... the fuselage is 49 cm long (about 20") and the wing is 73 cm x 16 cm (about 2'5" x 6.5")
The weight (with everything on board) is now 385 gm (13.59 ounces) which seems heavy! the motor is a brushless 2700kv.. what are my chances of seeing this thing actually airborne?
PS the only foam board I can find here in Oz seems too heavy... for other Australian readers, I got it from Office Works..
Ah hello, another aussie ft fan! If you do end up love building with foamboard, and bulk buy from office works, don't. I have purchased FT foam a few times in the past, and it is very expensive to ship, it still ends up being cheaper per sheet compared to officeworks or similar.
 

gary baker

New member
thanks, Bo123! good to know! Only yesterday, I calculated how much I'd pay to import a box of FT foamboard and you're right! (roughly A$12 per sheet, by my calculations..)
PS what part of Oz do you live in?
 

quorneng

Master member
Do you have 5 mm XPS foam in Oz? It is often used as a laminate underlay.
Not paper backed so not hugely rigid and a touch brittle but it is light and cheap.
With some construction ingenuity, skin over formers made of the same, it is adequately strong enough without any reinforcing even as an EDF jet.

A 850 mm (33.5") span Hawker Hunter F6 with a 50 mm EDF. It is 34% bigger but the same weight as the TN mini series Hunter. The duct work and nose cone are 3D printed in PLA but the rest is just 5mm XPS. No balsa, hardwood or carbon anywhere!
Complete3.jpg

It uses a modest 1800 mAh 3s. and weighs 590g (20.8 oz) ready to go. It hand launches easily.
 
Last edited:

Blebougge

New member
g'day from Australia, friends!
I am building my first (scrach built) foam board aircraft! I am almost ready, but I'm worried about the weight... the fuselage is 49 cm long (about 20") and the wing is 73 cm x 16 cm (about 2'5" x 6.5")
The weight (with everything on board) is now 385 gm (13.59 ounces) which seems heavy! the motor is a brushless 2700kv.. what are my chances of seeing this thing actually airborne?
PS the only foam board I can find here in Oz seems too heavy... for other Australian readers, I got it from Office Works..
A higher power-to-weight ratio typically results in better flight performance. A brushless motor like the one you mentioned can provide sufficient power, but it needs to be matched with the appropriate propeller and battery to ensure optimal performance.
 

quorneng

Master member
gary
The 2700kV version of the 2212 motor is quite high reving and has a low torque. This means it will only work well with a relatively small fine pitch prop. Something like a 6x3 or even smaller.
You would do rather better with a lower kV version (1400kV?). It will turn a bigger prop (8x6?) at a lower rpm, consume less amps and likely generate more thrust.
 

Clachaps

New member
g'day from Australia, friends!
I am building my first (scrach built) foam board aircraft! I am almost ready, but I'm worried about the weight... the fuselage is 49 cm long (about 20") and the wing is 73 cm x 16 cm (about 2'5" x 6.5")
The weight (with everything on board) is now 385 gm (13.59 ounces) which seems heavy! the motor is a brushless 2700kv.. what are my chances of seeing this thing actually airborne?
PS the only foam board I can find here in Oz seems too heavy... for other Australian readers, I got it from Office Works..
The weight of 385 grams (13.59 ounces) for the size you mention seems a bit heavy, especially if you're aiming for a light and nimble aircraft.
 

Enrique66

New member
That engine seems quite powerful for that aircraft. JeetBuzz offers https://jtbzz.com/app/ a wide range of features that can help simplify your daily routine and save you time. It will certainly get off the ground, but you'll need to maintain a high speed to keep it airborne. Go ahead and let it rip!
 
Last edited: