FT Tiny Trainer - Softening tail stability with crashes...

[sdietric]

Yes, I am still learning, and hence, my landing aren't that smooth (and include some occasional crashes into fences or other objects...)

What I am noticing is that the foam in the tail section of the tiny trainer is breaking (underneath the paper) and it's becoming wobbly very quickly. I have rebuilt the tail section about three times. This time I put four wooden sticks already on the end section, just to find that it now breaks further in the front (so I included some wooden sticks from the outside. Also using tape for more stability on the top and the bottom, but still, after a while I am wondering if it makes sense to just rebuild the whole tail section out of balsa wood or have dowels running the full length of the tail from the beginning.

Anybody has some opinion / experience / suggestions on this?

Thanks so much!

 

[JasonK]

From my notes, I have rebuilt the Tiny Trainer 6x between me and my oldest learning to fly (my younger ones have been buddy boxed and the number of relevent crashes has been nearing zero for us). Rebuilding is just something that ends up needing to be done. I am curious how your managing to do so much damage the tail, most of my damage was to the front 'pod' part from nose in crashes. I don't think I have had to repair/replace one due to damage in that area.

 

[sdietric]

I think it's from head on crashes into something. It's just that the foam cracks under the paper, and then it looses stiffness... I tried with Elmers foam and Ready foam, and the Ready foam from the dollar store is actually better, the Elmers foam is heavier and more sturdy, but cracks completely, while the Ready form at least keeps it together.

 

[Hai-Lee]

I just remove the outside paper on the sides of the tail and laminate the sides with 1mm Balsa with the grain going from the front to the rear.

When dry the tail is a fraction heavier BUT the strength increase is quite massive.

If you model is very weight sensitive you can reduce the balsa thickness and the weight with a little careful sanding.

It works for me

Have fun!

 

[LitterBug]

What kind of foamboard did you originally build it from? I have found the FT foamboard to be more durable than Dollar Tree....

 

[bisco]

i use dtfb, and have found you can only repair so much before the plane isn't flying right, and crashing becomes almost inevitable.
i would build a new one, not use elmers, and if you cannot find help learning at a local club, consider a gyro like aura 5. that is how i learned, and it helped tremendously.
for small light strengthening, i like carbon fiber from radical rc

 

[sdietric]

Added some images below from this morning to show the degree of the problem. The fuselage just bents and looks like a banana after a while...

The wing is Elmers foam board - rock solid.
The fuselage is Dollar Tree foam board (which is the same as FT foam board which is only more waterproof).

I use a lot of tape which also adds some waterproofing. I do like the idea of using balsa for lamination.

 

[JasonK]

Added some images below from this morning to show the degree of the problem. The fuselage just bents and looks like a banana after a while...

The wing is Elmers foam board - rock solid.
The fuselage is Dollar Tree foam board (which is the same as FT foam board which is only more waterproof).

I use a lot of tape which also adds some waterproofing. I do like the idea of using balsa for lamination.

Looks like your due a rebuild of the fuselage.

 

[bisco]

elmers is stronger, but heavier. it's a personal choice

 

[Monte.C]

Added some images below from this morning to show the degree of the problem. The fuselage just bents and looks like a banana after a while...

The wing is Elmers foam board - rock solid.
The fuselage is Dollar Tree foam board (which is the same as FT foam board which is only more waterproof).

I use a lot of tape which also adds some waterproofing. I do like the idea of using balsa for lamination.

Looks like your due a rebuild of the fuselage.

Yeah you're holding it together long past its "Use By" date! I think there are only so many crashes until you rebuild. That's ok, building is fun and you get to do it better this time.

In a rebuild you might consider running two small pieces of basswood through the back half of the fuse, from under the wing back. At the hobby shop you can find 1/16"x 1/2", 3/32"x 5/8", whatever feels right. Or don't crash!

 

[Piotrsko]

Be advised that making things stronger generally makes other pieces break faster. Eventually it is so strong it is too heavy to fly, but then it won't crash either.

Used to be there were triangle balsa strips that glued into the fuselage corners and bent really easy to follow the fuselage profile and really stiffened the fuselage

 

[Hondo76251]

This is how i look at it. Weight means speed and speed will make landings more difficult and crashes more severe.

I used to go to great lengths to beef things up but I've since found that trying to make things lighter, especially for trainer style aircraft, works much better. Elmers can do just fine, especially if that's all you can get, but I'd recommend the adams board first because its much lighter and tends to break in a much more repairable way. (Although I'd go with the white board as the black doesnt seem to work as well, or just use the FT stuff)

If you start as light as possible the plane will inevitably gain weight as repairs are made. If you start at max weight the repairs will quickly make the plane less stable and harder to fly and will necessitate even more repairs.

I like to start off using as little glue as possible. (gorilla glue if you really want to keep weight down) I like to remove inner paper in key areas like inside the upper wing half and inside the tail of the fuselage. The reinforced packing tape is an excellent choice but use sparingly as it is heavy. I like to use one strip on the bottom of the wing as a sort of external spar, and two half strips down the fuselage.

I have best luck making repairs with gorilla glue instead of hot glue as the hot glue tends to melt the foam when making repairs in cracks. Just put a light smear in the crack then a piece of tape over it. The tape secures the compromised paper and the glue foams up to bind nicely to the board. Very light and strong.

Good luck on your continued flying!

 

[Monte.C]

This is how i look at it. Weight means speed and speed will make landings more difficult and crashes more severe.

I used to go to great lengths to beef things up but I've since found that trying to make things lighter, especially for trainer style aircraft, works much better. Elmers can do just fine, especially if that's all you can get, but I'd recommend the adams board first because its much lighter and tends to break in a much more repairable way. (Although I'd go with the white board as the black doesnt seem to work as well, or just use the FT stuff)

If you start as light as possible the plane will inevitably gain weight as repairs are made. If you start at max weight the repairs will quickly make the plane less stable and harder to fly and will necessitate even more repairs.

I like to start off using as little glue as possible. (gorilla glue if you really want to keep weight down) I like to remove inner paper in key areas like inside the upper wing half and inside the tail of the fuselage. The reinforced packing tape is an excellent choice but use sparingly as it is heavy. I like to use one strip on the bottom of the wing as a sort of external spar, and two half strips down the fuselage.

I have best luck making repairs with gorilla glue instead of hot glue as the hot glue tends to melt the foam when making repairs in cracks. Just put a light smear in the crack then a piece of tape over it. The tape secures the compromised paper and the glue foams up to bind nicely to the board. Very light and strong.

Good luck on your continued flying!

Double like.

 

[bisco]

it's a tough lesson for us beginners to learn, because it is counterintuitive

 

[Monte.C]

it's a tough lesson for us beginners to learn, because it is counterintuitive

On the surface it seems counterintuitive.
My whole nose section is called "the crumple zone".
Listen, if your plane were made of anything else it would be in a dozen pieces by now.

 

[Hondo76251]

it's a tough lesson for us beginners to learn, because it is counterintuitive

Its part of the journey, something we all do!

Id say the other thing we are all guilty of is keeping damaged airframes and repairing them far too many times because we sort of get attached to them i suppose. Gotta remember, the electronics are reusable, the airframe is two bucks worth of foam and a bit of glue! You'll find you can build the second (or 3rd or 4th) one better and more quickly each time.

 

[Monte.C]

!!!!
It's just a cardboard toy you made out of craft supplies!

 

[bisco]

agreed. the biggest thing for me in making a new airplane when the old is unrepairable, is the time and effort.
i'm lazy, and get bored easily. if it cannot be repaired to fly well, i'd rather build a whole new model.

 

[sdietric]

I decided in the end to rebuild the fuselage inserting this time wooden dowels along the edge of the vertical pieces and completely laminating it with reenforced tape. The result is extremely sturdy - and predictably heavy.

That said the airplane flies again, and it flies beautifully, though noticably faster, nearly racing speeds...

The issue with the foam is that is just softened up with use. I am attaching a photo of the old fuselage I cut open where you can see all the wrinkles after like 10 hours of flying the airplane with a good number of crash landings...

I am not used to this softening. I used to fly balsa wood airplanes, and they were either whole or broken. As the foam airplane weakens, it becomes more and more uncontrollable...

 

[bisco]

if you like em heavy and fast, nothing wrong with that, better in the wind too.
i like slow and floaty, so it's a different issue.

maybe you can find a better medium to build with. epp is supposed to be pretty resilient