Will this motor will provide enaugh trust for 900g trainer with 8x4prop

[Juice]

https://hobbyking.com/en_us/turnigy...939&indexName=hbk_live_magento_en_us_products

 

[JasonK]

it is rated for Thrust: 700g on the page, so if a 8x4 prop is what it wants, that is what you should expect for thrust.

it has a max listed power of Max Power: 150w

the size motor by aircraft type was recently answered here:
https://forum.flitetest.com/index.php?threads/plane-stability.66210/#post-631812

900g -> ~2lb
so we have ~75w max power per lb
so per that chart [70 to 90 watts per pound is perfect for trainers and slow-flying aircraft], it would be on the low side of acceptable for a trainer.

 

[JasonK]

that is assuming you mean thrust and not trust... I have not used that motor and don't know if it can be trusted.

 

[Juice]

it is rated for Thrust: 700g on the page, so if a 8x4 prop is what it wants, that is what you should expect for thrust.

it has a max listed power of Max Power: 150w

the size motor by aircraft type was recently answered here:
https://forum.flitetest.com/index.php?threads/plane-stability.66210/#post-631812

900g -> ~2lb
so we have ~75w max power per lb
so per that chart [70 to 90 watts per pound is perfect for trainers and slow-flying aircraft], it would be on the low side of acceptable for a trainer.

But I have heard that you onl'y need 60% thrust

 

[BATTLEAXE]

But I have heard that you onl'y need 60% thrust

60% of thrust is 60% of the thrust you have. 60% of 700 grams of thrust still wont get a 900 gram plane to fly at 100% throttle.

What is this trainer you are putting the motor on?

There are a bunch of cheaper options for more powerful motors if price is the issue. Check on Bangood or Aliexpress

We need more info man, more then just the title of the thread

 

[JasonK]

But I have heard that you onl'y need 60% thrust

with a really well designed plan and really good pilot I suspect the thrust to weigh ratio could be rather low. That said, I haven't see anything mentioning that low of a recommended thrust to weight ratio for a trainer, perhaps you could provide a reference to this documentaiton and then we can compare it to our experiences.

 

[Foam Folder]

I think a low thrust to weight ratio only means low climb rate:
A long time ago I had a power pak for my hang glider, 65lbs thrust 300lbs weight was 50'per minute climb. ,22% ratio
F86 Saber 5200lbs thrust, 14000lbs aircraft. .37% thrust ratio 7500'per min climb

 

[JasonK]

there is a minimum thrust needed, what ever is needed to overcome the drag at the speed needed to generate the lift needed to keep from descending.. and then something a bit more then that to be able to climb.

So it doesn't only mean a low climb rate, to low and you can't even stay up.

 

[Juice]

How much static thrust do i need for 1000g plane?

 

[JasonK]

look at the chart linked here:
https://forum.flitetest.com/index.p...-900g-trainer-with-8x4prop.66219/#post-631976

how much static thrust you need depends on the flight characteristics your trying to get.

 

[Pieliker96]

But I have heard that you onl'y need 60% thrust

As long as the thrust-to-weight ratio (TWR) is greater than the drag-to-lift ratio, the airplane will fly in level flight. For example, a plane with a mass of 1000g and a lift-to-drag ratio of 10 would only need 100g of thrust for level flight. But it couldn't climb or turn because those require excess power (more than 100g of thrust). I've flown several planes with a TWR lower than one, mostly EDFs. For a trainer, though, I'd recommend a TWR of 1 or greater for the ability to get out of hairy situations. It's also generally more fun to fly with a TWR > 1, as it allows for higher-energy aerobatics and 3D maneuvers.

 

[Juice]

Is there any way to get large thrust with smaller motor. Or all your planes have 10inch props?

 

[Juice]

Could you recommend some good motor manufacturers

 

[BATTLEAXE]

With the C pack radials most of us use the 9-10" prop range. Usually the thrust will be determined my RPM speed. The faster you spin the prop the more thrust it will make. You could go to 4 cell batteries to put more voltage to the motor, as long as your gear is compatible with it.

I am a fan of the SunnySky brand, recently purchased three motors from them actually. I was so impressed with the first one I bought another two. This guy John of RCVideoReveiws has a lot of good things to say about them as well

 

[Juice]

Could you recommend motor that provide about 800g of thrust with fairly small prop

 

[Bifi.baarlo]

Almost every 2205 drone motor will provide 800gr. thrust with the right prop, I have a lot of planes with Racerstar motors, the 2300KV version provides about 800gr. thrust on 3S with a 5045 prop.

 

[Juice]

Almost every 2205 drone motor will provide 800gr. thrust with the right prop, I have a lot of planes with Racerstar motors, the 2300KV version provides about 800gr. thrust on 3S with a 5045 prop.

Do you need any prop adapter to mount the propeller?

 

[Bifi.baarlo]

Normally drone motors and props don't need any adapters.

 

[Juice]

Normally drone motors and props don't need any adapters.

But how do you know if the prop hole will match the motor shaft diameter?

 

[Bifi.baarlo]

It is standard 5mm for drone props and motors, plane props mostly come with spacers so they also should fit.