Plane building help

[Muggers1234]

Hi all,

So I finally got the plane together, I put the electronics together with a Turnigy 45amp ESC and a 1000kv 3542/6 turnigy motor with max 38A and 600watts.
I ran a watt meter and the plane is pulling 36A and about 380 watts with a 12x4.5 slow flyer prop. When the battery is fully charged and I go full throttle, my voltage alarm set at 3.8 goes off strait away. I'm concerned that it's drawing to hard on my 2200 3s 25c battery?
Could anyone tell me what I'm doing wrong? Also what does the 6 mean on the 3542/6 motor?

Thanks!!!

[dfw]

At that discharge rate you may expect a voltage drop happening, you probably want to lower the alarm, 3.8 is on the high side, you would expect to get alarms under full throttle at that setting.
Battery should be able to deliver 55 A continuous max, you seem to sit well below that.

not sure on the motor marking.

[Babar]

i no longer rely on the buzzer...once i put it in the yak54 4cell ...straight away it started beeping...its only good for models like bixler/sports cub etc
never rely on it

[Muggers1234]

Thanks for your help, I'll se the voltage alarm to 3.5 and hope for the best when I maiden it haha

[dfw]

If you look up Lipo discharge graphs, you 'll see they all drop significant voltage under load, but then sustain voltage relatively stable under load until they are discharged, and you get another quick drop down. It's the second drop where you do damage to the cells if you go over the edge.

[Chris Mc]

James, I flew my Tundra straight out of the box on 3S 2200 mah 25c and 40c. Never had a problem, 6 minute flights and still land with 3.6 left on the battery. I'm using Turnigy's from Hobby King.

With careful flight you could get 8 minutes.

[Muggers1234]

Hey Chris,

Thanks for that, I'm loving the Tundra, favourite plane by far I'm getting similar flight times to you.
What I'm mentioning above is the new Hobbyking Yak 54 that I bought.
I maiden'd it on Wednesday and it made this weird noise strait away. I have a video with it now. It's weird that it didn't make it when I was testing the motor and dialing in the throttle curve. I only flew for 30 secs before coming down and ripping out the landing gear in the mud haha.

So here is the video, is it possibly an unbalanced prop? I have 2 of these 12x4.5 slow flyers and they both do it, but the 11x5 normal does not. Any thoughts?

https://youtu.be/nECVrD8p7sA

Cheers,
James

[Quadzimodo]

Hey Chris,

Thanks for that, I'm loving the Tundra, favourite plane by far I'm getting similar flight times to you.
What I'm mentioning above is the new Hobbyking Yak 54 that I bought.
I maiden'd it on Wednesday and it made this weird noise strait away. I have a video with it now. It's weird that it didn't make it when I was testing the motor and dialing in the throttle curve. I only flew for 30 secs before coming down and ripping out the landing gear in the mud haha.

So here is the video, is it possibly an unbalanced prop? I have 2 of these 12x4.5 slow flyers and they both do it, but the 11x5 normal does not. Any thoughts?

https://youtu.be/nECVrD8p7sA

Cheers,
James

Floppy prop I reckon.

[Babar]

i think you have a flexible propeller....
i have observed this kind of noise with flexible props on 3d planes but they were slow flying ones like the epp hand launch version

change your prop to APC or other hard ones...i think the prop isnt meant for these high revolutions

[Muggers1234]

Ahhh okay, makes sense. It is pretty flexible. Thanks for the help

---

So would you recommend not using a slow flyer on this plane? And if so what should I use?

[Spook]

Muggers, swap it out for a APC slow flyer prop and do a balance on it before using it.
The sound in the video is the vibration going through the body of the motor mount and planes body.
It will kill the plane if that vibration keeps up.

[Muggers1234]

Thanks for that, I have a balancer coming and bought an APC 12x6 normal and a 11x7 Slow Flyer as that was all thats available. Give those a go see what happens!

[Chris Mc]

Just another tip, not sure how long you have run the motor for but I would be checking the motor mount screws as well as the screws holding the motor to the mount. They do have a tendency to loosen if vibration occurs.

[robbo]

Agree with other comments that slow-fly prop is going too fast. I think it is either flexing and creating a resonance. Btw you should be able to see the flex by looking from the side of the prop, put a piece of white paper or ruler, as you accelerate you will see the tip move forward... NB most props flex at tips its a matter of degree.

Or, it could also be a prop-stall, where the airflow cant get around the prop, being a slow fly, wide at the tips and spinning so fast, it could be stalling... it's making the right sound for that, do you lose some thrust when you get the noise that would be an indication. Play with different props, you might want to try e-calc to help find the right prop size. https://www.ecalc.ch/

FYI- https://www.rcgroups.com/forums/showthre...Prop-Stall

[Babar]

Agree with other comments that slow-fly prop is going too fast. I think it is either flexing and creating a resonance. Btw you should be able to see the flex by looking from the side of the prop, put a piece of white paper or ruler, as you accelerate you will see the tip move forward... NB most props flex at tips its a matter of degree.

Or, it could also be a prop-stall, where the airflow cant get around the prop, being a slow fly, wide at the tips and spinning so fast, it could be stalling... it's making the right sound for that, do you lose some thrust when you get the noise that would be an indication. Play with different props, you might want to try e-calc to help find the right prop size. https://www.ecalc.ch/

FYI- https://www.rcgroups.com/forums/showthre...Prop-Stall