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FT Racer Build

BATTLEAXE

Well-known member
#3
Got my newest build almost done and ready to maiden. Unfortunately the weather is supposed to be unfavorable for the next few days. Running a power pack C with a 9x6 APC prop. Can’t wait to see her go. My wife keeps wanting to paint eyeballs on the canopy😁
Nice! What battery are you using in it?
 
#6
Maiden flight went great today. Plane flew like it was on rails. Could definitely use a bigger battery. Broke the prop upon landing because I ran out of elevator authority at slower speeds.

Can anyone supply a solution for that? Maybe mixing some throttle and elevator or programming flaperons?
 
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BATTLEAXE

Well-known member
#9
Yes, I have the Spektrum DX6e. Great idea. I’ll change the elevator rate to a higher setting. Thanks for the idea and reminder.
What prop and battery were you using on it? Judging by the fact that you were saying a bigger battery I am guessing you want to go faster, or was it tail heavy?

This being a pylon racer, well a tamed down version of a pylon racer, it will land hot, they all do. If you want to fly fast the low rates is all you need, the higher speed makes the surfaces more effective, so less travel is needed. The high rates will be for slower speeds, like landing. @Sero installed flaps on his but his has been modified for speeds of 100+mph so slowing that one down takes the flaps just to make it manageable for landings. The ailerons as flaperons might not be enough surface area to chain the beast.
 
#10
What prop and battery were you using on it? Judging by the fact that you were saying a bigger battery I am guessing you want to go faster, or was it tail heavy?

This being a pylon racer, well a tamed down version of a pylon racer, it will land hot, they all do. If you want to fly fast the low rates is all you need, the higher speed makes the surfaces more effective, so less travel is needed. The high rates will be for slower speeds, like landing. @Sero installed flaps on his but his has been modified for speeds of 100+mph so slowing that one down takes the flaps just to make it manageable for landings. The ailerons as flaperons might not be enough surface area to chain the beast.
I’m using the APC 9x6 prop and Tattu LiPo Battery Pack 1300mAh 45C 3S 11.1V.

I rechecked the throws last night and the elevator travel was only half of what it could be. So I adjusted it to full travel on 100% expo. Once the weather clears I’ll see if that makes a difference. I did notice yesterday on the maiden flight that it took a lot of area to complete a loop.
 

Wildthing

Well-known member
#11
I’m using the APC 9x6 prop and Tattu LiPo Battery Pack 1300mAh 45C 3S 11.1V.

I rechecked the throws last night and the elevator travel was only half of what it could be. So I adjusted it to full travel on 100% expo. Once the weather clears I’ll see if that makes a difference. I did notice yesterday on the maiden flight that it took a lot of area to complete a loop.
I don't think you want to run 100% expo, maybe 50% tops.
 

Sero

Well-known member
#12
I’m using the APC 9x6 prop and Tattu LiPo Battery Pack 1300mAh 45C 3S 11.1V.

I rechecked the throws last night and the elevator travel was only half of what it could be. So I adjusted it to full travel on 100% expo. Once the weather clears I’ll see if that makes a difference. I did notice yesterday on the maiden flight that it took a lot of area to complete a loop.
I don't think you want to run 100% expo, maybe 50% tops.
Yes use 30% expo, 40% max IMO and increase your rates. Run dual rates and use a switch, low rates for medium-high speed flying and low rates for launching, landing and slow flying.

Everybody has different tastes on how to set-up their planes, above is what I do for my Racer and some other planes with wider speed envelopes., other planes I will set-up different depending on how they fly.

To get good control authority at slow speeds all you can do is increase your rates, slowing the plane down with flaps will only reduce authority as there is less airflow over the control surfaces making them less effective.
 
#13
I don't think you want to run 100% expo, maybe 50% tops.
I was only going to use 100% for the elevator when landing. Not for the entire flight.

Also added some more paint and tape to the current scheme. Makes orientation easier.
I don't think you want to run 100% expo, maybe 50% tops.
 

Attachments

The Hangar

Well-known member
#15
I was only going to use 100% for the elevator when landing. Not for the entire flight.

Also added some more paint and tape to the current scheme. Makes orientation easier.
The racer looks good! However, 100% expo would be like putting the elevator on a 3 position switch. I have never ever put more than 40% expo on anything, and that I only use on 3D planes in high rates. Other than that, I use 30% expo on basically everything.
 
#16
I’m using the APC 9x6 prop and Tattu LiPo Battery Pack 1300mAh 45C 3S 11.1V.

I rechecked the throws last night and the elevator travel was only half of what it could be. So I adjusted it to full travel on 100% expo. Once the weather clears I’ll see if that makes a difference. I did notice yesterday on the maiden flight that it took a lot of area to complete a loop.
Quick question, do you know the difference between expo and dual rates? If so could you tell me what they are?
 

Sero

Well-known member
#17
@Hineybadger expo (exponential) is different than rates and increasing your rates is what you need. Expo make the sticks a little less sensitive around the centre area. Rates are how much the servos and therefore the control surfaces move in distance.

Below is a graph of 30%, 0% and 100% expo. the horizontal line is the position of the transmitters stick whether its the rudder, ailerons or elevator, the vertical line is the servo position and the diagonal line where they meet. You can see 0% is a straight line. 30% is levelled off a bit in the centre which help de-sensitize the controls and allow smoother flying while not limiting your throws. 100% is very flat in the middle and in that area the plane will not respond to stick movements and then suddenly move dramatically, this is a good way to loose control.

The below graphs are set to 100% throws and moving them to 125% will make the diagonal line end in the corners of the box, reducing the throws will make the diagonal line more horizontal.

Expo.jpg


Hope that helps.