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I need help, to at least not crash on take off.

Pluc

New member
#1
Okay, I'm puzzled. I'm new to the hobby of RC Planes. Since I knew that I was gonna crash at first, I went for the foam board building and I bought necessary electronics. As of now I've built 5 different planes. 2 from other sites (The maker hanger 2 and the mermaid.) 1 try at my own design and 2 from the flite test swappable series (the FT Racer and the FT Old Fogey). The problem is... None of them took off. As soon as they leave the ground or my hand, they bank left hard and crash on the left wing. (I'm serious, everyone of them cashed on the left wing).

There is no RC club or hobby shop where I live (eastern Quebec). So I can't ask help directly. Can someone help meunderstand why my planes bank hard on the left, even if it work hard to make them as straight as possible, even if I balance the C.G. a little to the front and no mater the direction and the force of the wind.

I use a A2217/5T 1500kv motor, a 2200mah 3S battery and the recommended prop on each model.
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#2
Hey Pluc!

Welcome to the forum!

the left roll is a dead giveaway -- you're getting beaten up by torque roll. The motor at WOT (wide open throttle) is generating quite a bit of torque on the airframe, but the strongest single thing to counter it is airflow over the wings . . . which at takeoff is almost nothing :p

a few things you can try:

- Right thrust angle --nudging the motor to point a little to the right will generally help reduce the airframes torque roll. a thin washer or two between the motor mount and the firewall will do wonders here.

- Launch at 1/2 to 3/4 throttle (NOT WOT) -- you should have enough thrust to get the plane accelerating at less than full throttle, and then as it picks up speed, the lift generated by the wing can better counter the torque. generally from a hand launch of a torquey airframe I start with "just enough" thrust to get started and the belly just grazes the grass as I pull away. that totally counts as a successful launch.

- build a twin engine airframe with counter rotating props -- if the motors cancel the torque by themselves, torque roll isn't an issue and you can get better at the flying part.

Torque roll can be a pain to learn with, but it *CAN* be beat!
 

ruud

Senior Member
#3
To add to the excellent points Dan made, make sure you don't take off too early. Build up some speed on the ground (or firmly toss the plane) first.
 

RAM

Posted a thousand or more times
#4
Great explanation Craftydan. I'm somewhat of an expert at crashing on takeoff and would only add that I plan on purchasing a multiwii for $15 to use as a gyro on my next attempt. It seems like a small price to pay for a beginner without anyone to help them. It won't help with torque roll for the reasons you explained but should help once airborne.

Do you think adding wheels for takeoff vs. hand launching would help him much?? I ask because the rollout of a wheeled takeoff might help him a little as the speed builds vs. hand launch.
 

Pluc

New member
#5
Thank you guys. I'll try those tricks. I have a smaller motor I haven't tried yet, I'll try it, I guess It's gonna have less torque. Like RAM I also ordered a gyro a couple days ago, I hope it's gonna help to learn, because I live in a windy place, near the ocean. I admit that I take off early because the plane turns toward the left and exit the runway. Anyway it's still very fun to build the planes.
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#6
Great explanation Craftydan. I'm somewhat of an expert at crashing on takeoff and would only add that I plan on purchasing a multiwii for $15 to use as a gyro on my next attempt. It seems like a small price to pay for a beginner without anyone to help them. It won't help with torque roll for the reasons you explained but should help once airborne.

Do you think adding wheels for takeoff vs. hand launching would help him much?? I ask because the rollout of a wheeled takeoff might help him a little as the speed builds vs. hand launch.
Stabilizer boards as you mention won't help much until you're in a stable flight envelope . . . which at launch you're so close to the edge the slightest of stall can make the stabilizer do the wrong thing. But you're absolutely right -- they can make a modestly friendly craft into a VERY friendly craft, particularly in wind.

As for a ROG (rise off ground) takeoff, so long as you don't stall by climbing too fast, as Ruud mentions -- once you stall there is no help from the wing. You can't float off the ground without sufficient lift from your wings, so if you let the plane float up off the ground the torque should be manageable. Now goosing the throttle on a small plane on the ground might tip you over, ending an otherwise good takeoff with an embarrassing pitchover . . . but on grass those generally don't end with much damage. Asphalt or concrete can chew up the prop like that, however. Smooth increase in power is how you safely get away from the lower edge of the flight envelope.
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#7
BTW pluck, you mentioned you've built the Mermaid (I'm assuming that's the model very similar to the slow boat). Have you tried a grass-slide takeoff with it? It might need a bit of "up" as well for thrust angle to keep the nose from being forced down, but that should give you an easy ROG takeoff, so long as the grass is still damp from morning dew.
 

Pluc

New member
#8
Well In didn't try much with the mermaid. I only tried it once. I tried a slide take off on a dirt road, then it rolled to the left, it crashed and the left wing completely torn off. So it took me about 8 hours to build and 3 seconds to destroy. I would say that this model is nice but the wings are very fragile.

BTW throwing really does'nt work for me. When I ordered my transmitter I ordered the wrong one by mistake, My trottle is on the right so I have to throw with my left hand and I'm not a lefty. So... I put landing gears on my planes and take off from the ground.

Thank you for the input. Right now it's raining but as soon as possible I'll try again with my Old Fogey and see what happens.
 
#10
Hey! It flew! My battery un hooked itself at about 10 feet in the air after take off and fell in the tail so I lost control and it just went up in the air doing crazy uncontrolable loops and turns, I lowered the trottle to bring it down as gently as possible in the tall grass without braking it but hey it's a first flight.

Your trick with the washer worked great I took off and landed a couple of times and it never rolled left. Thanks a lot Craftydan.
 

krinaman

Senior Member
#12
If you aren't dead set on building your own plane I would suggest buying a beginner plane. Something like a sport cub S or apprentice from Horizon with SAFE on it.
 
#13
You can probably switch the controls on your radio to make it operate like a mode 2.

try an FT Flyer, or even a Storch since you have decent build experience. There are some super cub plans floating around too.
 

kacknor

Build another!
#16
BTW throwing really does'nt work for me. When I ordered my transmitter I ordered the wrong one by mistake, My trottle is on the right so I have to throw with my left hand and I'm not a lefty. So... I put landing gears on my planes and take off from the ground.
Can I ask what radio you have? If you are stuck in Mode 1 it's usually (not always) possible to configure it to the U.S. normal Mode II with throttle on the left.

JD
 
#17
Hkfidget, thanks for your help but I started this tread last year, craftydan gave me a lifesaver advice, since then I learned, i built and flown a dozen other planes. I have no trouble throwing planes or taking off from the ground now.

kacknor, Since I'm cheap I use the 4 channel non-programmable hobbyking transmitter. I know there is a way to mecanically change it from mode 1 to mode 2. there is a video on youtube on how to do it. But I got used to my transmitter and I learned to throw with it. If I changed it I would be very confused. But thanks anyway.
 

kacknor

Build another!
#18
Ha! I really need to learn to check dates. That what comes from just checking New Posts. ;)

Glad it worked out and you are having fun! Me too!

JD