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Corsair

#1
Hi Guys!
I’ve built the Corsair below.
FB08BBA4-FBC7-41C3-8098-BD88B90907C9.jpeg
had to add weight to the nose to balance as foamboard here in the uk is slightly heavier.
As it’s gone to fly it’s seems to set off level and nosedive. As it balances is this due to a lack of power? As the plane is heavier than spec? I’ve built the plane with an 1100kv motor, 45a esc and 2200mah battery. Do I need a higher Kv so it gets up to speed faster? Any help would be greatly appreciated!
 

quorneng

Well-known member
#2
Mattelson
Nice build.
Its all up weight would be useful and the exact specification of the motor along with the prop you are using. It would also help you gave where the balance point is - distance back from the leading edge.
This would enable a judgement to be made on whether you have sufficient power.
How experienced are you in flying RC? A Corsair is not exactly a 'learner' plane.
 
#3
Mattelson
Nice build.
Its all up weight would be useful and the exact specification of the motor along with the prop you are using. It would also help you gave where the balance point is - distance back from the leading edge.
This would enable a judgement to be made on whether you have sufficient power.
How experienced are you in flying RC? A Corsair is not exactly a 'learner' plane.
🤣 I built and f22 and that flies well, other than that flew the baby p51 with a giro. Not the most experienced, when flying I don’t seem to have a problem it’s just I come across stumbling blocks like this and need a bit of help. All up weight roughly 1300g. Prop is 10x4.5. Motor I’m using is 1100kv brushless motor. ( not sure on exact spec )
Balance point is around 28% back from leading edge. Roughly 7.5cm.
 

quorneng

Well-known member
#4
I assume you are using a 3s battery.
The kV of a motor has no bearing on the power it can produce only the speed it will try to run at. Put too big a prop on any motor and it will simply over heat and fail that is assuming the ESC does not blow up first!
So without knowing the spec of the motor and/or the amps it is using (measured with a watt meter) it is impossible to say if you are short of power.
If you can measure the full power Watts figure then there are power to weight guide lines. For something like a Corsair you would need at least 100W/lb. So for 1300g (2.86 lb) you need something approaching 300 W or about 28 A from a 3 s battery.

At 1300 g all up your Corsair is not exactly a 'light weight' so it is likely to fly quite fast and a 10 x 4.5 is a fairly fine pitch prop which will simply run out of thrust as the speed increases. A 9 x 6 prop will use about the same power but is likely to be a better match for the motor and the plane. If that does not help then you will need a motor that can handle 300W from a 3s with a suitable prop.

As an example the 9 x 6 on an Emax 2822 1200 kV motor draws 17 A which is 175 W on a 3s (I have just measured it). However this is plenty for the plane, a 'stand off' scale Mustang about the size of your Corsair, as it only weighs 342 g or in other words it has 220 W/lb available at full power! :eek:

I can only repeat wherever there is a question concerning power a Watt meter is a vital piece of kit. It tells you exactly what is happening which not only gives you the power going to the motor but provided you know the specs of everything it also tells you if you are about to over load something expensive. Watt meters are not that expensive. You may have to solder on the connectors on it to match your battery and ESC.

I hope this helps.