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Help! Radial Twin C-pack

chris398mx

Well-known member
#1
Does anyone know how heavy of a plane can be flown with the Radial twin C-pack? I am building a scratch build bomber with a 72 inch wing span and the weight is adding up fast. I am not sure the twin C-pack will pull around this plane. Or does anyone know how much thrust one C-pack motor can produce on 3S or 4S? Any help is appreciated.
 

mach1 rc

Well-known member
#4
Oh
Does anyone know how heavy of a plane can be flown with the Radial twin C-pack? I am building a scratch build bomber with a 72 inch wing span and the weight is adding up fast. I am not sure the twin C-pack will pull around this plane. Or does anyone know how much thrust one C-pack motor can produce on 3S or 4S? Any help is appreciated.
Oh and what bomber are you planning on doing?
 

Zetoyoc

Well-known member
#6
Does anyone know how heavy of a plane can be flown with the Radial twin C-pack? I am building a scratch build bomber with a 72 inch wing span and the weight is adding up fast. I am not sure the twin C-pack will pull around this plane. Or does anyone know how much thrust one C-pack motor can produce on 3S or 4S? Any help is appreciated.
I do not have many props for my new c pack radial. and I do not have a 4s battery yet. but I did build and calibrate a test stand and have tested what I have. My best thrust so far is 1150g thrust pulling 23.3 amps using an APC 9x4.7sf prop and 3s battery. there is a lot more in this motor for sure. I just need more props and batteries to test :) I have a couple larger props on order, Ill let you know how they do when i get them.
 

chris398mx

Well-known member
#8
I do not have many props for my new c pack radial. and I do not have a 4s battery yet. but I did build and calibrate a test stand and have tested what I have. My best thrust so far is 1150g thrust pulling 23.3 amps using an APC 9x4.7sf prop and 3s battery. there is a lot more in this motor for sure. I just need more props and batteries to test :) I have a couple larger props on order, Ill let you know how they do when i get them.
So if I have 2 that is 2300g thrust. Do I need at least a 1:1 ratio thrust to weight to get it off the ground?
 

BATTLEAXE

Well-known member
#9
Does anyone know how heavy of a plane can be flown with the Radial twin C-pack? I am building a scratch build bomber with a 72 inch wing span and the weight is adding up fast. I am not sure the twin C-pack will pull around this plane. Or does anyone know how much thrust one C-pack motor can produce on 3S or 4S? Any help is appreciated.
Your twin C pack on 4s will draw a lot of amps compared to a 3s, also depends on the props you plan to use as well. What were you thinking of using for the props and ESC?
 

chris398mx

Well-known member
#10
Your twin C pack on 4s will draw a lot of amps compared to a 3s, also depends on the props you plan to use as well. What were you thinking of using for the props and ESC?
The ones that came with the Radial C pack.....35A esc's. supposedly you can use a 10 inch prop on 4S, but the motor gets pretty hot when I tried it. So if I use 4S, I will likely use a 9 inch prop. 3S a 10x45 SF.
 

BATTLEAXE

Well-known member
#12
The ones that came with the Radial C pack.....35A esc's. supposedly you can use a 10 inch prop on 4S, but the motor gets pretty hot when I tried it. So if I use 4S, I will likely use a 9 inch prop. 3S a 10x45 SF.
There is a lot of faux radial motor to get the airflow around. If the prop you have on there now is a 10x45 then that would be the smallest I would go. You don't need a high pitch on 4s either, the higher rpm will take care of that. Plus I am sure if your test was static while inside the faux radials you weren't getting sufficient airflow to cool the motor, that's probably why it got hot
 

chris398mx

Well-known member
#13
There is a lot of faux radial motor to get the airflow around. If the prop you have on there now is a 10x45 then that would be the smallest I would go. You don't need a high pitch on 4s either, the higher rpm will take care of that. Plus I am sure if your test was static while inside the faux radials you weren't getting sufficient airflow to cool the motor, that's probably why it got hot
It was on a different plane with a single motor. My version of a master series spitfire.
 

Zetoyoc

Well-known member
#15
i have a 9x7x3 and a 10x6e on the way shoudl be here monday.

to fly you need a lot less than 1:1 ratio power to weight. to take off or loop or other aerobatics needs a bit more. :)

here are some figures i quickly searched for a moment ago. take with a bit of salt. i do not know of thier validity

50-70 watts per pound; Minimum level of power for decent performance, park flyer/slow flyer models
70-90 watts per pound; Trainers and slow flying scale models
90-110 watts per pound; Sport aerobatic and fast flying scale models
110-130 watts per pound; Advanced aerobatic and high-speed models
130-150 watts per pound; Lightly loaded 3D models and ducted fans
150-200+ watts per pound; Unlimited performance 3D and aerobatic models


if i assume 12.4 v (likely lower) on my best test with the 9x4.7sf and 3s. it was 288 watts
 

Zetoyoc

Well-known member
#16