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FT-3D Dirt Nap - A preferred weight question

#1
Today I was intending to maiden the scratch build of the FT-3D. It was a normal day, but it turned out to be my worse flying day out of my 'career'. I had strayed from the recommending build, deciding to use a smaller propeller, .0947EF prop, than the recommending 1200kv motor. I only have the most used Turnigy 2200mAh 3S 20C Lipo, which has a listed weight of 188grams. The plane's weight listed without the battery by Flitetest was 439 grams, mine, without the landing gear or battery is at 418 grams with the smaller prop. With the larger recommending battery by Flitetest, the weight comes to 571 grams overall. Mine has a weight of 606 grams.

I hand launched the plane, had a bit of struggle since my rates were pretty high, and I leveled it. I gave it an angle to try and gain altitude, but the plane simply continued falling until smacking nose first into the ground and destroying my firewall. I'm rather new to flying a heavier plane, since the FT-3D is much heavier than the other foamy builds. I'm unsure what it would feel like exactly if the plane was over-cumbered with weight. I had ran out of that mentioned prop when I hit the ground and wondered if an 8x4 prop is good enough to use instead. Also, should I use the smaller recommended battery rather than the one I mentioned? I really would like to have a nice flying model but I'm always lost with how to get the parts right.

I appreciate the help, and if someone has advice on hand launching the FT-3D, I would appreciate that as well. I already lowered the rates much further down, and wonder also if 60% was good enough.
 

xuzme720

Dedicated foam bender
Mentor
#2
With lower rates, you should have little to no trouble flying underpowered as a conventional plane , IF the balance is correct. Heavy can be an issue if the motor cannot bring the plane up to a fast enough speed to carry the weight. The plane needs to fly fast enough to generate enough lift to carry the weight, so if you are planning to lower the power, putting the plane on a diet might be the way to go first. Lighter battery can be like a round of liposuction for the airframe to get you started on the weight loss...
 
#3
I planned to pick up a new much smaller battery, but the ones recommended on hobbyking were out of stock till recently, I tried to simply make due with what I have. Currently I'm simply trying to get the plane to fly, stunts come later. I forgot to consider the lift being proportional to the speed. The plane was roughly balanced to a bit of nose heavy at the imaginary line going through where the servo heads are mounted under the wing. Perhaps landing gear may make the take off easier as I can gain speed then take off than starting from a stopped start to instantly in the air. I did not use a power less than recommended, but because I'm using a heavier battery I think it may have not be matched well.
 

xuzme720

Dedicated foam bender
Mentor
#4
I really think most of your issue may have been too much throw if you are on the recommended setup. That will take the "normal" weight vertical and should have been enough to pull the extra weight. It might not be enough to pull it out of a stalled situation though which is where it sounds like it was until it hit the ground. Did you chop the throttle just before it hit and that's when it nosed in?
 
#5
I hit the 0% throttle hold right when I hit the ground, I did everything I could, but you could be right, I will be testing it tomorrow to see if I get anymore luck with lower rates. Perhaps I did stall out and was too low to correct it.
 

xuzme720

Dedicated foam bender
Mentor
#6
Stalling is phenomenally easy with the throws the FT3D is capable of. One thing to do before every maiden is a power off glide test. This will tell you a few things, one of which is how hard you need to throw the plane for it to fly. Some tall grass is recommended to land in if possible.
This is also an option to try to see how fast it needs to fly without too much risk to the airframe...
 

SteevyT

Senior Member
#7
I was going to do a glide test with my FT3D, but then I realized, there's no way I would be able to get it to glide. So I was going to do a straight run and just hop it into the air, which turned into a somewhat successful maiden flight. Except the entire flight was fraught with signal loss, including one right on landing which caused me to cartwheel. I should have done a range check first.