Help! Designing my first rc airplane. Need some help:)

[ItanMark]

Currently, I am designing a trainer RC airplane. It is going to weight about 730 g and have a wingspan of 1.04 m. Also, it is going to carry about 150 g of payload. (It is included in the weight) I have a few questions:
1. is a single 2212/1000 motor enough for my plane to fly as an average trainer would?
2. I have calculated the wing area and the area of the stabilizers. Now I need to design a fuselage. I know that when designing a fuselage , you should pay attention to the center of mass. But since I don’t have enough money to buy all of the components right now, I am going to be designing it on paper and I don’t know how to account for the center of mass.
3. How do you know, if your battery is running out of charge?

 

[Shurik-1960]

The most popular and affordable training models have long been known. For a 1m span, the flight weight of the model should optimally be from 200 grams to 450 grams + 150 grams of payload. To know in flight that the battery is almost empty, cheap squeakers from aliexpress have been used for a long time. The CG model for training flight has 25-30% of the wing chord. If everything is clear to you, success in designing. And I'll go to the store for beer and popcorn to keep track of your progress.

 

[ItanMark]

The most popular and affordable training models have long been known. For a 1m span, the flight weight of the model should optimally be from 200 grams to 450 grams + 150 grams of payload. To know in flight that the battery is almost empty, cheap squeakers from aliexpress have been used for a long time. The CG model for training flight has 25-30% of the wing chord. If everything is clear to you, success in designing. And I'll go to the store for beer and popcorn to keep track of your progress.

Thank you so much for your response! So if the CG should be 30% of wing chord, how do i know where it is on my paper drawing/blueprint?
Also does it mean, that the 2212/1000 is not going to be enough? (The wing is calculated according to my estimated weight)

 

[Shurik-1960]

Take the golden mean-25%. The wing width is 100 mm - the CG is located 25 m from the front of the wing. If you provide for mounting the wing on the fuselage with the possibility of shifting along the fuselage, then on an experimental model, throwing it into planning, you will be able to choose the perfect CG. 2212 -there are many engines of this brand and they vary greatly in thrust: your brick of 730 grams will pull 2212 :https://aliexpress.ru/item/40003483...=a2g2w.stores.search_results.8.49685244XoPvMN . While you're saving up for this motor, you can stick 60 grams of plasticine on the model layout instead of the motor.

 

[quorneng]

ItanMark
At the "paper" stage the centre of mass, also known as the centre of gravity, is at best a bit of a guess. With design experience you are better able to predict where it might end up. I assume the payload is over and above the the planes "ready to fly" weight of 730 - 150 = 580g
Your plane will have a relatively heavy battery, The simple solution is to design a long enough compartment in the fuselage so when you have built the complete plane you can place the battery to give the require balance position and then arrange a suitable fixing arrangement at that position,
In many respects electric is easier to balance simply because it has to have a heavy battery.

The cheapest way to know how long you can fly for is by experimentation. I assume you are going to use a LiPo battery and that will need a dedicated LiPo charger. You can buy a simple voltage checker that you can plug into the balance plug of a LiPo.
Make your first flight short just a couple of minutes. When you land you can check the cell voltages. They go from close to 4.2V fully charged but do take them below 3.5V at the end of any flight. If you do you are likely to permanently damage the LiPo
If the cell voltage is say 3.9 volts at the end of your first flight you can extend the next flight time a bit. Be aware that how fast the battery discharges does depend on how much throttle you use so the 'safe' flight time will vary but with experience you will be able to judge when to terminate a flight.

A design tip.
Build the plane as light as you can whilst maintaining adequate strength. The power to fly is directly proportional to its weight so the lighter the better.
With the right prop a 2212 1000kV will fly your plane but the 150g payload will certainly make it a bit harder to fly.
As an example this 1.016 m span plane used a 2212. It had foam wings and tail.

It flew very well indeed and with a 'cruising' throttle it could do so for 20 minutes or more but then it only weighed 425g ready to go.
Any chance of a picture of the layout of your plane?

 

[ItanMark]

ItanMark
At the "paper" stage the centre of mass, also known as the centre of gravity, is at best a bit of a guess. With design experience you are better able to predict where it might end up. I assume the payload is over and above the the planes "ready to fly" weight of 730 - 150 = 580g
Your plane will have a relatively heavy battery, The simple solution is to design a long enough compartment in the fuselage so when you have built the complete plane you can place the battery to give the require balance position and then arrange a suitable fixing arrangement at that position,
In many respects electric is easier to balance simply because it has to have a heavy battery.

The cheapest way to know how long you can fly for is by experimentation. I assume you are going to use a LiPo battery and that will need a dedicated LiPo charger. You can buy a simple voltage checker that you can plug into the balance plug of a LiPo.
Make your first flight short just a couple of minutes. When you land you can check the cell voltages. They go from close to 4.2V fully charged but do take them below 3.5V at the end of any flight. If you do you are likely to permanently damage the LiPo
If the cell voltage is say 3.9 volts at the end of your first flight you can extend the next flight time a bit. Be aware that how fast the battery discharges does depend on how much throttle you use so the 'safe' flight time will vary but with experience you will be able to judge when to terminate a flight.

A design tip.
Build the plane as light as you can whilst maintaining adequate strength. The power to fly is directly proportional to its weight so the lighter the better.
With the right prop a 2212 1000kV will fly your plane but the 150g payload will certainly make it a bit harder to fly.
As an example this 1.016 m span plane used a 2212. It had foam wings and tail.
View attachment 241433
It flew very well indeed and with a 'cruising' throttle it could do so for 20 minutes or more but then it only weighed 425g ready to go.
Any chance of a picture of the layout of your plane?

Thanks so much for the response! I am going to send the pic in a couple of hours!
Also did you mean do not take the battery below 3.5V? Also, i heard that 3S LiPo batteries produce up to 11V, so why do you say it produces 4.3 V when fully charged?

 

[ItanMark]

Thanks so much for the response! I am going to send the pic in a couple of hours!
Also did you mean do not take the battery below 3.5V? Also, i heard that 3S LiPo batteries produce up to 11V, so why do you say it produces 4.3 V when fully charged?

Also the layout is going to be pretty similar to like a piper j3 maybe. Also, just an info, the weight of the components is gonna be ~380g. From the airplane design tutorial, i found that the fuselage & wing weight is about the same as the component weight. And then +150 g for the arduino/camera

 

[Shurik-1960]

I've almost finished my popcorn, and the project is still at the stage of resembling Piper J3. I see how you literally piece together the necessary information.. The LiPo battery and others can have: 1 battery (1S), 2 batteries (2S) and so on... 1 S cell charged has 4.2 volts. The batteries in the battery are connected in series and the voltage is plus: 2S - 8.4 volts. Battery discharge is recommended up to 3.8-3.9 volts, since "smart" charging does not see a battery with a lower charge than 3.7 volts. The number of batteries in the battery is selected based on the characteristics of the engine (its power) and the regulator. 3S battery with 11 volts can be safely thrown in the trash.Based on my experience, with such a discharge, almost no battery bank is restored to normal. After restoration, I use such batteries in flashlights, since there is no current dissipation in them.

 

[ItanMark]

I've almost finished my popcorn, and the project is still at the stage of resembling Piper J3. I see how you literally piece together the necessary information.. The LiPo battery and others can have: 1 battery (1S), 2 batteries (2S) and so on... 1 S cell charged has 4.2 volts. The batteries in the battery are connected in series and the voltage is plus: 2S - 8.4 volts. Battery discharge is recommended up to 3.8-3.9 volts, since "smart" charging does not see a battery with a lower charge than 3.7 volts. The number of batteries in the battery is selected based on the characteristics of the engine (its power) and the regulator. 3S battery with 11 volts can be safely thrown in the trash.Based on my experience, with such a discharge, almost no battery bank is restored to normal. After restoration, I use such batteries in flashlights, since there is no current dissipation in them.

So a good LiPo with 3S should have 12.6V?

 

[Shurik-1960]

You're learning fast. So all is not lost yet

 

[ItanMark]

ItanMark
At the "paper" stage the centre of mass, also known as the centre of gravity, is at best a bit of a guess. With design experience you are better able to predict where it might end up. I assume the payload is over and above the the planes "ready to fly" weight of 730 - 150 = 580g
Your plane will have a relatively heavy battery, The simple solution is to design a long enough compartment in the fuselage so when you have built the complete plane you can place the battery to give the require balance position and then arrange a suitable fixing arrangement at that position,
In many respects electric is easier to balance simply because it has to have a heavy battery.

The cheapest way to know how long you can fly for is by experimentation. I assume you are going to use a LiPo battery and that will need a dedicated LiPo charger. You can buy a simple voltage checker that you can plug into the balance plug of a LiPo.
Make your first flight short just a couple of minutes. When you land you can check the cell voltages. They go from close to 4.2V fully charged but do take them below 3.5V at the end of any flight. If you do you are likely to permanently damage the LiPo
If the cell voltage is say 3.9 volts at the end of your first flight you can extend the next flight time a bit. Be aware that how fast the battery discharges does depend on how much throttle you use so the 'safe' flight time will vary but with experience you will be able to judge when to terminate a flight.

A design tip.
Build the plane as light as you can whilst maintaining adequate strength. The power to fly is directly proportional to its weight so the lighter the better.
With the right prop a 2212 1000kV will fly your plane but the 150g payload will certainly make it a bit harder to fly.
As an example this 1.016 m span plane used a 2212. It had foam wings and tail.
View attachment 241433
It flew very well indeed and with a 'cruising' throttle it could do so for 20 minutes or more but then it only weighed 425g ready to go.
Any chance of a picture of the layout of your plane?

JW, is styrofoam going to be good for the wing? I had an idea of bending it using a heat gun - don’t have the tools to do hot wiring

 

[Shurik-1960]

I saw a video on YouTube a long time ago, where an African cut out a profile wing with an ordinary sharp knife and then polished it to an ideal appearance.

 

[ItanMark]

Hello everyone! A little update: finished my first blueprint for my rc plane. Gonna transfer it to a bigger paper, so you can see the sizes.

 

[Shurik-1960]

1. Another type of model is missing from the drawing.Are you planning to make V wings for stable upper-wing flight? 2. Will the drawing of the model be paid for? 3. Will you patent your invention? 4. The muzzle of the fuselage for a specific motor with a long shaft? Is this done to reduce resistance?5. Why such a wide fuselage? To create a payload bay? In principle, 100% will fly with a thrust of 0.6 in flight weight from 200 grams to 700 grams.

 

[ItanMark]

1. Another type of model is missing from the drawing.Are you planning to make V wings for stable upper-wing flight? 2. Will the drawing of the model be paid for? 3. Will you patent your invention? 4. The muzzle of the fuselage for a specific motor with a long shaft? Is this done to reduce resistance?5. Why such a wide fuselage? To create a payload bay? In principle, 100% will fly with a thrust of 0.6 in flight weight from 200 grams to 700 grams.

Explain pls number 4. Also try not to use google translate, it does not always translate correctly.

 

[ItanMark]

1. Another type of model is missing from the drawing.Are you planning to make V wings for stable upper-wing flight? 2. Will the drawing of the model be paid for? 3. Will you patent your invention? 4. The muzzle of the fuselage for a specific motor with a long shaft? Is this done to reduce resistance?5. Why such a wide fuselage? To create a payload bay? In principle, 100% will fly with a thrust of 0.6 in flight weight from 200 grams to 700 grams.

Also why should i be patenting it? It is literally just a blieprint taht i am making, to make building the plane easier.

 

[Shurik-1960]

The front part of the fuselage is usually designed based on the diameter of the motor, which should be freely installed with an offset of 3 degrees to the right and 2-3 degrees down for upper-wing models. The engine must rotate freely in the nose of the fuselage and receive air blowing for cooling. I live in Moscow, in Russia, where bears hug and drink vodka. I am 63 years old and I knew English very well 23 years ago: I was visiting San Francisco. About the patent-it's a joke.

 

[ItanMark]

What do you mean by “the engine should rotate freely”? My engine is about 3 cm wide, so is a 4cm wide nose going to be enough? Also did not know about the angles, thanks! Also, does anybody know, if i can bend styrofoam via heating it up? I’m currently thinking, about how i am gonna be making the wing.

The front part of the fuselage is usually designed based on the diameter of the motor, which should be freely installed with an offset of 3 degrees to the right and 2-3 degrees down for upper-wing models. The engine must rotate freely in the nose of the fuselage and receive air blowing for cooling. I live in Moscow, in Russia, where bears hug and drink vodka. I am 63 years old and I knew English very well 23 years ago: I was visiting San Francisco. About the patent-it's a joke.

 

[Shurik-1960]

For me: Styrofoam is a plate with dimensions of 60mm x 1000mm x 1500mm.It is used to insulate buildings . I cut the wings out of this material with a heated string. I don't understand what kind of material you want to use.

 

[ItanMark]

For me: Styrofoam is a plate with dimensions of 60mm x 1000mm x 1500mm.It is used to insulate buildings . I cut the wings out of this material with a heated string. I don't understand what kind of material you want to use.

Hello! Just found out, that ALL of the foam i bought for my plane is totally unusable. When cutting it, it more like cracks and produces these awful little white particles. Questioning my life choices. Also planning a trip to the store.