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Second attempt into this hobby

#1
Hello all!

I've always wanted to fly an RC Plane since forever. Being a person who loves making stuff, I was inspired by this video(It flies so beautifully).So after searching and reading forums and build guides on the internet for months, I've scratch built a similar model:
IMG-20170422-WA0023.jpg IMG-20170422-WA0024.jpg IMG-20170422-WA0030.jpg IMG-20170422-WA0033.jpg IMG-20170422-WA0034.jpg

It looked great (at least to me), but didn't fly more than a couple of seconds...and it wasn't designed to sustain crashes (I'm highly optimistic :p):

I'm not sure if it was the bad design or bad launch (or both), but I think that I need some practice on some trainer plane and atleast have something to fly...then I could look back into fixing this. So I looked at the Tiny Trainer kit and it seems great and the same kit is available at my local hobby store here in India. But my question is: Can it run on the existing parts I have? Which are:
motor
esc
battery
prop
I think the ESC and battery fit fine in the recommended specs but the motor falls short in kV...what does that mean exactly? And the prop was supposed to be for a slow flyer: 8x4, so I gues I'll have to buy new ones for this?

Any advice would be great!
 

JimCR120

Got Lobstah?
Site Moderator
#4
Hello Srijal,
It's hard to be sure but one common thing new pilots do is pitch up too sharply and then stall the plane out. It looks like this might have been what happened on yours. Planes need airspeed.

I haven't built the Tiny Trainer yet so I can't help much there. If the motor and airframe didn't work together, what would you prefer to change?

Welcome to the Forum. Would you tell us more about yourself in a brief intro?
—Jim
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#5
IMO that plane you are flying is too delicate for a beginner.

The TinyTrainer foamie can take a beating. I flew the exact same flight you just posted 10 times before I got my trainer working and all I had to do was patch it with some packing tape and try again.

The key was the ability to repair in the field in minutes making crashes painless and finding someone who knew how to trim a plan in flight.

Crashes for beginner pilots are common and shouldn't ruin the plane.

I run a much smaller/faster motor (1806 2300kv) with a 6" prop on 3S for my tiny trainer. I think your motor will work but will be heavier and generate more torque and thrust. Still the tiny trainer is unbelievably forgiving and IMO will take it in stride.

Welcome to the FliteTest forums! :)
 
#6
If the motor and airframe didn't work together, what would you prefer to change?
I would prefer to change the motor in this case as I want a 'tried and tested' airframe, but being a student I would like to save as much as I can here so I'm looking for views on what I plan to do, like: "No way that would work!" or "Umm..Maybe?"...something like that.
I think you're right about me pulling the sticks too back, causing it to stall. But I have 0 experience on how a plane should feel and I built the control surfaces mostly on intuition...so a lot of factors could have gone wrong :p

Thank you for your opinion @cranialrectosis. So in this case, lower kV means lower rpm per volt which compensates the power as higher torque and thrust? Am I correct? What would that result on the plane?

Would you tell us more about yourself in a brief intro?
Thanks for the welcomes. I'm a 19yr old engineering student pursuing a degree in electronics, here in India. I love all kinds of science projects and building stuff and I'm also fairly decent in programming. This was my actual first attempt building a plane, started 4yrs back:
1608617_768683203161717_65219939_n.jpg
I don't have pictures of it in full shape...this was after I removed all the parts in it. It looked great but the foam was too soft and the wings drooped downwards. Tried adding supports for it but the whole build would bend easily and it couldn't fly. I immediately started making the stick fuselage model and it got dragged for 2-2.5yrs after which I found a friend who actually flew some planes and so I decided I try this one out. Result was the crash I uploaded. So after all this time, now I saw some flite test videos on youtube and I think this time I can get something to fly.
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#7
So in this case, lower kV means lower rpm per volt which compensates the power as higher torque and thrust? Am I correct? What would that result on the plane?
Yes.

More torque will mean your prop will have more tendency to roll the plane.
 
#9
"roll" as in how?
Roll as in cause it to spin about it's long axis. Once the plane gains some speed, the wing will counteract this tendency. But, when you first launch it or while taking off, the roll can be hard to control. An 1806 motor with a 6x4 prop makes for a nice starter plane because the prop isn't too big and does not cause a lot of roll. However, an 1806 with a 3S will provide adequate speed once the plane gets moving. Even 2S works well enough because the plane is lighter. It only takes a few meters for the plane to really start flying at about 1/2 throttle.

Try and get a better 1806 if you can and using 3S. The cost difference between a good and a not good one is about $2. However, the better ones can handle a lot more current. At least according to their specs. With a 2S battery, the motor choice might not matter as much.

Mike
 
#10
Okay so I think I'll get the Tiny Trainer kit first and try it with the motor I already have and see how that goes...If its bad, I'll get the 1806 as you guys suggested. Does that sound good?
Will the 8x4 prop work or do I need 6x4 for the 1500kV motor as well? Less speed so a bigger prop would work I guess?
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#11
For a slower motor speed use a longer prop.

If you go 1806 2300kv on 3S consider an HQ 5030. I also liked Gemfan 5030 triblades on that plane when I first started out. It can do loops rolls and mild tricks and has a nice speed range. Go to a 6045 if you still want more power.
 
#12
Okay cool. Thanks a lot!
I'll get back in a month or 2 with more news, got exams going on now. Please let me know here if anyone has more suggestions or something.