Do you notice design flaws with Flite test?

[ashoka232]

Hey guys, have any of you built Flite test planes?
I've built a few and have found a couple issues constant when it comes to their design choices. in general and especially for the trainers there isn't enough emphasis on rigidity or survivability. Infact just by looking over the design in certain models the flaws really show through. Its even worse for scratch building because some planes are needlessly complicated with fewer benefits to justify the effort required.
New pilots in this hobby seem to be their main demographic but their design philosophy is coming from an experienced and advanced perspective with its biases. Personally I always add some reinforcements with pieces of wood and from in the more flimsy areas. For some models there needs to be huge changes in how they are built.
All of this is prompted by one of my ft planes having its wing snap in half which could have been avoided by using wood and heat resistant glue.

 

[Flying Monkey fab]

There is a whole section here for resources if you think you have made a significant improvement to a plane.

 

[Piotrsko]

I have found most structural failures in flight test foamies can be caused by either my intentional shortcutting during the build process or doing something way beyond the design specs. If you take a pound of anything and impact the ground above walking speed, the energy moments are severe enough to mess up anything less than a steel plate. Otoh, my KFM foam flying wing resisted flying through a chain link fence. Did bend the lipo battery.

 

[Foamforce]

All of this is prompted by one of my ft planes having its wing snap in half which could have been avoided by using wood and heat resistant glue.

Which plane was that, out of curiosity? I’ve built a lot of FT planes (30+) and only ever had two wings fold. One was on my son’s Tiny Trainer, but that was his glue job and I knew that it wasn’t done well. The other was my son’s Mini Guinea. In that case it wasn’t a full wing fold, but it creased a few inches out. In that case it was because the access panel that was cut into the wing for easier wiring caused a weak spot. On our replacement wing we omitted that.

Other than those two experiences, the only frequent miss with regards to the design is the landing gear for the Cub/Scout/Stick. The tab system gets ripped up immediately, even with decent landings. The solution to that was to build the tab out of plywood (which was done on later models such as the Tutor) and reinforce the slot with Popsicle sticks. Or use 3d printed parts for that.

Other than those, most designs seem pretty good. I would say that they’re designed for light weight and repairability.

Did you have some specific plane models in mind that have issues we could help with?

 

[Merv]

...only ever had two wings fold...

You are just not trying hard enough.
I like high G maneuvers & have folded many wings. I'm a believer in the bamboo skewer spar. At the wing joint I imbed 2 in the top skin & 2 in the bottom skin, about 1.5 inches apart. The spar goes between the two wing halves. I have folded a wing with one 1 in the top & bottom but I have not been able to fold 2. But I'll keep trying.

...I always add some reinforcements with pieces of wood ... one of my ft planes having its wing snap in half ...

I also went down that path, constantly reinforcing the weak area. I discovered that the plane still broke, just somewhere else, in the new weak area.

I have changed my thinking, now I plan the weak spot, somewhere will be quick & easy to fix. This have made my planes far more robust. For example, I use zip ties to attach my landing gear, WHEN there is a rough landing the gear is ripped off. But it's an easy fix, just replace a few zip ties & I'm back in the air.

The whole FT ethos is sharing ideas that make flying more safe, fun & affordable. No longer is it for those who prefer flying expensive planes in a circle. Not that there is anything wrong with that. But now we have choices.

I would not call them flaws, FT has just not yet invented the perfect plane.
Let's continue moving forward, sharing ideas with the community as we seek the perfect plane.

 

[Foamforce]

You are just not trying hard enough.

Ohhh, I beg to differ. 🙂 I eagerly explore the limits of my planes. I’ve even managed to break the power pod loose a couple times during flight, but the wings have been stubbornly strong. I suspect that making the gaps as small as possible and using adequate (and hot) glue, along with the tape. I’ve been very surprised.

That said, I only fly with 3s, so I may be able to break wings more prodigiously with 4-6s. 😀

 

[Merv]

...That said, I only fly with 3s, ...

I also use 3S. Glad you have had better results than me.
In my wings, I like to go fast, currently I use high Kv motors, 3,000+. I'm beginning to think, for more speed I should lower the Kv, & increase the prop pitch.

 

[Tench745]

Hey guys, have any of you built Flite test planes?
I've built a few and have found a couple issues constant when it comes to their design choices. in general and especially for the trainers there isn't enough emphasis on rigidity or survivability. Infact just by looking over the design in certain models the flaws really show through. Its even worse for scratch building because some planes are needlessly complicated with fewer benefits to justify the effort required.
New pilots in this hobby seem to be their main demographic but their design philosophy is coming from an experienced and advanced perspective with its biases. Personally I always add some reinforcements with pieces of wood and from in the more flimsy areas. For some models there needs to be huge changes in how they are built.
All of this is prompted by one of my ft planes having its wing snap in half which could have been avoided by using wood and heat resistant glue.

My first FT plane was the FT Flyer. It's a super simple plane; you can draw it out on foam board just by taking measurements from the pdf, you don't even need to print the plans if you don't want to. More and more the FT designs have followed the technology that FT has available to them. The plans have gotten more complex, intricate, and difficult to cut out without a laser. When they first started, FT plans were just their own in-house laser cutter files stuck into a PDF with a little polishing for us to use. Now Sponz takes those plans to a new level of polish, but I believe the designs are, as ever, intended for laser cutting.
As for weak spots, everything is a compromise. It sounds like FT chose a different set of compromises than you would prefer. That's the one benefit of building these planes ourselves though, we can modify them as we see fit.

I know I simplified my FT Scout slightly when building it. When I built my FT Speedster I added the battery hatch from the FT Sportster. My Simple Soarer eventually got an Armin style wing and then I moulded a fiberglass fuselage for it because I was tired to snapping the foam one in hard landings. My Sea Angel is built entirely from de-papered foam board with a carbon fiber arrow shaft for a wing spar. And the second iteration of my Blunt-Nose Versawing merged features of the Versa and the Spear for a different compromise of strength and convenience.

 

[CrshNBrn]

I've got a video somewhere on here with my Me-262 folding its wing in flight and falling out of the sky. That was exciting. I think the wooden spar that is included in the kit is insufficient. That's the only example I can think of a FT kit that is a little sketchy, and I fly pretty aggressively.

 

[LitterBug]

I have crashed my FT Tiny more times than ot should have survived, including a few cartwheels down the field. It is now 8 years old and has held up well with some hot glue and skewer patching. The only fold I had was when the glue had come loose on a wing after sitting in the back of my truck after FF'23. Again, a little hot glue, and it was back in the air.

 

[Piotrsko]

That said, I only fly with 3s, so I may be able to break wings more prodigiously with 4-6s. 😀

I might suggest a square loop after a dive of a couple hundred feet. Done improperly, it should break even an acro glider wing. How would I know? Extra points if it breaks on the top of the square loop.

 

[Foamforce]

I might suggest a square loop after a dive of a couple hundred feet. Done improperly, it should break even an acro glider wing. How would I know? Extra points if it breaks on the top of the square loop.

Will you be at FF24? I’ll seek you out for some wing-breaking tips. 😁

 

[Merv]

I might suggest a square loop...

The square loop is one of my favorites. The rolling circle & knife edge round out the top three.

 

[Flying Monkey fab]

I might suggest a square loop after a dive of a couple hundred feet. Done improperly, it should break even an acro glider wing. How would I know? Extra points if it breaks on the top of the square loop.

You have entered the place where every machine is a smoke machine if misused bad enough and every plane is breakable.
I've watched people snap parts off of $3000++ airframes with high energy maneuvers.

 

[Piotrsko]

You have entered the place where every machine is a smoke machine if misused bad enough and every plane is breakable.
I've watched people snap parts off of $3000++ airframes with high energy maneuvers.

Ahh you have interpreted my comments correctly. The point of foamboard is just that: a wonderful cheap thing for whacking upon to make fun flying machines with minimal skill, nominal technique for Joe average.

Also responds to TLAAR engineering, they fly, too

Look at what @L Edge or @FoamyDM does and tell me that isn't cutting edge.

 

[Foamforce]

Soooo… are you guys getting together at FF24? I’d love to see your flying, and try to learn some maneuvers from you. My two boys, 9 and 11 would like that too.

 

[Merv]

Soooo… are you guys getting together at FF24?...

Im planning to be there.

 

[LitterBug]

Im planning to be there.

I'll be there. Volunteering as well.

 

[leaded50]

dont forget also that better rigidity or survivability, will make models more work to do for some, and it can also make models stiffer to break another things than eg. just the front. Then it will be more work to make it flyable again. Also eg. by making it very stiff against motor, or motorpod, it will be easier that eg. the motoraxle get bent... (ruins motor... )
Its not everytime more strength eg is best, sometimes not.....it will all depend on your own whishes!

 

[Crashmorflymor]

😆 yes there are many flaws but they aren’t made to last. You very likely will not be handing any of these down to your grandchildren. They are made out of cheap foam board. I doubt anyone at Flite Test will ever say their airplanes are meant to last. They are meant to build quickly, fly well, and be fun. They achieve that goal very well. If you want a plane that can potentially last decades build with balsa.