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First electronics, first scratch build, first crash

brox

Junior Member
#1
Hi Guys,
I just had my first experience building and trying to make it fly. I've been watching FliteTest videos for months now and would like to thank them for making the R/C plane hobby more approachable. My plan is to scratch build the FT Flyer and learn from there but i got impatient waiting for months for the foamboards resupplied in our local school supply shop (I look everywhere as hard as i can but only found it National Bookstore). So i decided to use styrofoam and do hotwire cutting so ended with a flying wing.

Here's how i tried and crashed everytime :D
https://www.youtube.com/watch?v=b-oM4PSX5JI

Here's my prop after the first try
P_20151207_100648_1_p.jpg
Is the damage that bad already?

I did do the high five, battery check, range check, CG (as good as i can) before the first throw.

At the start of the video i had to do the 2 leads switching even though I know i have my motor running counter-clockwise and have my props numbers facing front (direction of plane) but somehow it is running backwards. Do you guys know why?

My take away is I need a slow flyer so I can get accustomed to the controls. And i forgot to put the stabilizers on the sides.

Sorry if i'm in a field with kids running around but i do make sure nobody is in the line of my throw. I'm in a beat-up baseball field.

Would like to know your insights and advises.

here's my plane
Wingspan = 39inches
Propeller = 8x4 GWS
Motor = Emax BL2215/20
ESX = HobbyWing Flyfun 18A
Battery = 3s 18650 (recycled but its been charged way back and in storage for months) all 3 are at 4volts when i use it here
Servo = 8.5g emax
TX/RX = 6ch FlySky T6

Do you guys know if a half inch thick styrofoam good enough for the wings of the FT Flyer?
 
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#2
Hello and welcome to the Flite Test forum. First thought here is to improve your throw technique. Try turning your hand over, fingers on top, thumb on the bottom. That way you can get a better toss. The plane seemed to glide fairly well before you got your hands to the controls. Try not to pitch up so much until the plane begins to fly and gains some speed. Then, slow small control inputs. Most of all, don't give up. You'll get it and have fun!

I think 1/2" foam is way too thick for the FT Flyer. The foam! board we use here is 5mm (about 3/16" thick) Depending on the motor you have, you might babe able to use plain corrugated cardboard and get it to fly. In any event, best of luck to you.

Mike
 

brox

Junior Member
#3
Ah yes, I forgot that part of throwing technique. Yeah I have problems with getting the controls that's why i thought i should consider making a different slow flying plane. Frankly I can't remember the controls i'm doing after the throw and i think i'm afraid of pushing the throttle that's why my wing is pitching up but not flying up.

The wing is still intact but i need to enlarge the hole of another prop. :D
Thanks Mike.
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#4
Hey Brox, Welcome to the forum!

Just because you've got the numbers pointing in the direction of motion, doesn't mean the prop has to blow air back if the motor is CCW . . . there are two directions of props. There's a little bit of interaction between the prop's designed direction and the thread direction on your prop adaptor (get them paired up the wrong way and the adaptor will *SLOWLY* work it's way loose over several flights), but otherwise, numbers forward, and spin in the direction that makes the air go back. Doesn't matter which way on electric fixed wing, just swap any two motor leads if it's blowing the wrong direction, just like you've done.

As for next flights . . . if you haven't gotten to the point you are no longer trying to remember what the controls do but instead letting your hands run on muscle memory, a flying wing probably isn't the best thing to fly. They're typically VERY durable, and can have a wide flight envelope, but they can be very pitchy, and rarely self-stabilize in roll. a GREAT second plane . . . but first? Not really.

For the FT Flyer, I'm not sure cardboard would be up to the task (it might be, but probably needs a bit of re-enforcement, and you'd want the "grain" running span-wise, not chord-wise), but if you can get any ~4mm coroplast (corrugated plastic sheeting) it would probably work. A bit heavy, but more than strong enough. Alternatively, if you can find 6mm depron, or other XPS foam you'd be better set with those. The EPS Styrofoam and XPS are nearly identical chemically, but XPS is formed in a way that the cells are smaller and better melted together. because of this, XPS is usually easier to work with and comes in MUCH thinner sheets. Hard to say what you can get in sheet building insulation in a warmer climate like yours, but most any XPS will work better and easier than EPS.
 

brox

Junior Member
#5
Yeah that makes sense.I need to make the motor spin the opposite of how the prop adapter locks. Just like in Electric Fans. Then if the prop is not blowing backwards, I'll just flip it. Is that right or i need to get another prop that's designed the opposite of what i have?

Now that i've tried it, i really don't think i can learn from it. I feel like i can't keep up on what controls to do after throwing. I should have tried building a slow flyer with just rudder and elevator.

I think I saw those coroplast in the school supply store. i just need make sure it's long enough and consider the grain direction. It should be running like a spar. correct? left to right not front to back. Then pair it with styrofoam fuselage.
Thanks CraftyDan
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#6
If the prop is blowing backwards when spinning in a direction that will tighten the nut, then you'll have to trade the prop to get it to blow the other way without reversing the motor direction . . . but the loosening isn't very fast. As long as it's tight at the beginning of each flight, it should be fine -- just a good habit to check it in pre-flight.

For either coroplast or corrugated cardboard, the flutes are the grain. Absolutely right -- like a spar. EXACTLY, like a spar. biggest loading on a wing is the weight of the airframe pulling against the lift spread across the wing. First mode of failure in a wing is folding upward like a taco, usually at or near the root, so you want it to be stronger against bending from tip to tip than leading edge to trailing edge.
 

kacknor

Build another!
#8
I'm not the most experienced guy here, but my first impression is it looks tail heavy. My Bonsai, even with a 17 gram motor still needed and extra 20 grams of weight in the nose. Also, once you get the motor spinning the right direction, make sure the prop faces forward. The numbers must be towards forward end.

Don't give up!!

JD