I build, I crash. What am I doing wrong?!?

Flite Risk

Well-known member
Absolutely! Timmy is 100% correct. Becoming successful is not giving up, it took me forever to just throw and go but I got there. Simulator time was huge for helping me, don't overlook that.

To get real good if your simulator allows it like pickaSim does, increase your wind speed, your wind gust, the turbulence and try to fly in really adverse conditions.


New member
Hi Everybody -

Wow! Thanks for all the replies and the advice. So to answer a couple of the questions that have been posed:
  • Crap! The dihedral on wind is not symmetrical. I used a dihedral on both sides when I built the wing and at the root they both have an angle of 15 degrees. However, the left side is straight and has a vertical height of 1 7/8" at the tip, but the right side is bowed upward such that its vertical distance is 2 7/8". Its obvious as I look at it now...
    So that results in the left dihedral generating about 4% greater lift than the right.
  • Thrust angle is 2 degrees right and 2 degrees down. At least that is the starting point. All bets are off once I crash.
  • I probably did launch it at too high of an angle. I wanted my friend to take a video, so I launched it by myself.
  • I didn't think that the elevator could make that much difference. BTW - the control surfaces were all trimmed to be level and I didn't even have time to adjust the stick.
  • The control rod is shorted than the original design. I didn't notice the bent rod, but again the control sufaces were all level at launch.
  • I did a test glide and it flew straight and level.
  • The one issue that I have with the CG is that I always end up tail heavy. Is there a concern that adding putty as ballast would make the plane too heavy? This is the primary reason that I increased the length of the nose.
  • And yes - I thing my tweaks are causing too many unknowns. Since I need to rebuild, I am going to follow the plans to the T. Also the CAD model is just an aside, I teach CAD to sophomore mechanical engineers, so creating a solid model is just 2nd nature.
So thanks again for all the help and advice. I will post again after I build the new plane. I think that I should do this BEFORE I go ahead and try to build the duct tape plane!

Great, waiting for the report.


I build a new Tiny Trainer from scratch, I used dtfb (note the use of the acronym!) and the dry mass came out to be 180 g. The FT plans give a mass of 193 g, so I was (am) feeling good about the build. In order to get the CG correct with a 3S 850 mAh battery (80 g), I had to push the battery back such that the center of the battery was about an inch behind the leading edge of the wing. To fine tune the balance I used two stainless steel balls (total mass of 12 g) taped to a piece of fb and pushed into the tail section.

I had glide tested the plane and I got the 2nd base slide described by Piotrsko, I had practiced the hand launch with my heavier Elmer's foam board - I had to insert a couple of 1/4 inch sockets into the nose to get it to balance, but I think that I more or less had the idea after a bunch of throws. This is a link that shows the ugly, the bad and the good.

So today I went out for a maiden flight and my hand launch was one of the ugly ones. I "think" I threw the plane forward but with an upward pitch, so it stalled, rolled over to the left and crashed on its nose - broke the prop and the firewall, so back to the bench for repairs. Next time I will bring a helper to hold the radio while I launch. At this point, I just want to get it into the air in level flight. As soon as I get that I want to bring the throttle to zero and make sure that I can land without crashing.

Each time I do this I think about Wilbur and Orville and realize that they must have been just a little bit crazy!!

Onward and upward...

p.s. Some of you might note that I can't bring myself to use the term weight when I am using the grams. I have drilled the concept of weight as w = mg into my students so many times that I can't bring myself to write "dry weight is 180 g". However, I will refrain from giving the weight in Newtons, but for those that are curious the dry weight of my plane is 1.77 N.


Old and Bold RC PILOT
I have built Tiny Trainers using what FB is available and so many were quite heavy. I have added landing gear, flaps, and higher power and heavier motors. I have even built a few as canards and with a massive increase in wing span. In addition I built a couple as Spitfire lookalikes and used catapult/bungee launching successfully hundreds of times with the various versions I have flown.

The only real things to remember is that you normally do not need to really throw a TT on launch, (even a heavy one), but rather guide it in the direction you want it to go, (INTO THE WIND), and concentrate on launching it nose first.

Apart from the elevator you should be able to launch it without reaching for the controller immediately as the bird is inherently stable when setup and trimmed properly.

The biggest errors in building a TT or almost any plane for that matter are;
1. wings not of equal profile
2. wings joined together improperly and one wing having a greater angle of incidence than the other.
3. wings are of different weight or area.
4 on the TT the wing should fit flat on the fuselage top. Do not increase wing incidence without a valid reason as it can easily stall the bird at low speed.
5 do not try to launch at either too slow or too high a speed but rather let it coast out of your hand.
6 Allow the bird to fly. Panic and over-controlling can and does cause the majority of problems for the beginner. Try to only use the controls when you absolutely need to.

The TT should almost fly itself regardless of its weight. Heavier means faster!

Have fun and good builds/luck

Flite Risk

Well-known member
did your flght look like this?

That is what a tail heavy plane looks like. but based on your glide video i bet your flight doesnt look like this.


SUCCESS... well success for me anyway. It flew! It actually flew. I crashed it about 30 seconds after launch but it actually flew!

I now need to work on the advice I got from Hai Lee:
Allow the bird to fly. Panic and over-controlling can and does cause the majority of problems for the beginner. Try to only use the controls when you absolutely need to.

As I had mentioned in my previous post, I had rebuilt the FT Tiny Trainer out of dtfb and had crashed it on its maiden. I then took the time to practice throwing it as a glider just to verify that it was actually pilot error instead of a problem with the build.

I went out today for a second try. I didn't have anymore two-blade props, so I switched to a 3-blade Gemfan prop 6x4.2. I dragged my son along and we practiced throwing it back and forth to get the motion correct and then we moved onto powered flight. For the first attempt, I threw the plane and I had my son on the radio. It flew but not for very long. We then switched and I was able to actually fly it - but this is where a good pilot and a buddy box would come in handy. I crashed and the nose broke, but I am putting this one in the success column.

Time to rebuild the nose and maybe i can try again tomorrow before it starts snowing.

Some pics showing the plane properly balanced at the 1.75" mark given in the plans and the result of my first successful flight!

TT-correct CG.jpg


Participation Award Recipient
wow... that was quite the crash. I crashed my TT endless times when I was learning to fly and none of them looked like that.

might just be related to the camera angle, but it looks like the tail may be bent also.


I think some of the issue is that I spent some time over a couple of days practicing my launch. I had removed the motor and battery and was using a 3D printed "nose cone" that I had built for a previous project. It turned out that it provided just enough mass to allow the plane to balance at its CG.
While practicing my technique was good, throwing it so that it landed in the snow a few dozen times probably wasn't great for the foam board. Even though it was cold outside, the foam board got wet.

This is the link to a one-minute compilation of some of the glide tests. The tendancy for it to go left was because the rudder wasn't quite straight. I finally removed the wing and adjusted the sevo manually and I finally got a glide that flew nice and straight. Just before I threw it angled up so I landed on my nose!

One other thing that I forgot to mention is that I am going to replace my control rods. I was using .032" music wire, but it is a bit too flexible. I am going to install some .046" FT rods that I received after I had completed the build.

Flite Risk

Well-known member
Excellent. Congratulations.

I commend you for having the fortitude to see it through.
keep it up. you are well on your way.
See you at Flite Fest.


wow... that was quite the crash. I crashed my TT endless times when I was learning to fly and none of them looked like that.

might just be related to the camera angle, but it looks like the tail may be bent also.

Well its pretty snowy in NH right now, so I am planning on rebuilding the entire plane...


I teach engineering at UMass Lowell and have been remote since last March. I've been down to campus a couple of times since then, but I never went through the hassle of getting access to anything but my office. This week I finally decided that it was about time to also get access to our MakerSpace.:cool:

While real scratch building has it's charms, having access to a laser cutter does make the build (and rebuild, and rebuild) process a little more bearable. I now have enough parts cut for three Tiny Trainers. Once I can get that plane into the air - I'll move on to something like the Simple Cub. :unsure:


Stress Test

Well-known member
If you can swing it I recommend RealFlight 9.5 either with the controller or get the dongle to use your radio.

I would just practice touch and go's and how my thumbs should move when the plane is coming from my left or right.

It has made a real difference in my skills.

Also crashes are fixed by pushing the space bar. :D