FT Cub Owners/builders thread- off topic allowed!

[Steve Fox]

A place for people to discuss the FT Cub, Modifications and for new builders to ask questions and advice, i have built enough of these and flown hundreds of hours with them that i know what works and what does not and happy to answer beginner questions and help others skip the experimentation i have done to get mine flying like they do

I want to start by saying that i am cool with people going off topic, conversations drift and as someone whos been moaned at about doing it on here myself i dont have a problem with it in this thread, i wont complain that its being hijacked

The Cub has a good raw air frame and can be a very good plane if ALL FT specs are thrown out the windo.
It can fly very well and benefits from being heavier than the all up weight of 489g that official specs give, that is far too lightweight for anything but absolute zero wind!

As someone who has built loads of these and flown them almost every day for the last 3 years i have tried all manor of things and this is the specs i recommend:

Servos -12g metal gear!
Motors - i use both 2212 1400kv and 2830 1300kv
Props - I run 9x5
Much bigger battery's! - the smallest i run is a 2700mah 3s and the largest is a 4200mah 3s!,

The Cub loves an all up weight of 890g with a 2700mah 3s but will fly on a 4200mah 3s and an all up weight of 1.1kg!

Here is a complete list of my own Cub's specs and links to each item:

MG90s Metal gear servos, ESSENTIAL!!!!
https://www.banggood.com/custlink/3mKDok2HJA

Racerstar 2212 1400kv motor
https://www.banggood.com/custlink/G3DmE4HsKb

9x5 Prop
https://www.banggood.com/custlink/vDKKd0HsRq

30A esc
https://www.banggood.com/custlink/mmKKY6FAvT

Batterys i fly the cub on:
2700mah 3s
https://www.banggood.com/custlink/KGmvR4HnR3

4000mah 3s
https://www.banggood.com/custlink/3vKKFFm2zz

4200mah 3s
https://www.banggood.com/custlink/vDvKyQ1hRE

Eachine 5258 800mw vtx
https://www.banggood.com/custlink/vvDGDLMQWW

Flysky FS-iA6B receiver
https://www.banggood.com/custlink/mGvvEe5QWv

Cheap micro fpv cams x2
600tvl (forward)
https://www.banggood.com/custlink/DK3KYePbdg

1200tvl (downfacing)
https://www.banggood.com/custlink/DvGGR4PAEN

Cam switcher
https://www.banggood.com/custlink/K3mDhOJfuG

Stand alone voltage osd i use, works well but under reads by 0.6v and so im showing 9.4v when im really 10v but like a fast or slow clock, you know what it really means and i may just have a bad one, others may well read bang on:
https://www.banggood.com/custlink/DGDKL22Zj6

future builds with no FC will be using this OSD, it can be flashed with a standalone version of MWOSD and be used for a voltage display and you can configure it ro diplay how and where you want, it can also act as a stand alone gps decoder and display speed and distance without an fc with MWOSD firmware flashed! :
https://www.banggood.com/custlink/3KDvYA7m1i

Forget putting your battery under the power pod, strap your esc under there and put your battery IN the pod!
build the under nose piece to come right up to the front for better aerodynamics and have a \_/ shape cut into it to clear the esc when sliding the pod in and out as well as giving enough airflow to it.
put a shelf behind the windscreen for your rx and any other electronics you have (i run a voltage osd and a cam switcher in there too) and run your vtx on the side of the fuse under the wing.

Milk jug plastic on the leading and trailing edges of the wing where the rubber bands pass over will stop them cutting into the foam, the same milk jug plastic bonded to the belly will make your belly landing cub last forever!

I use prop spacers where the wing pegs pass though the foam, they are glued in and prevent the foam from being ripped apart over time or in a crash!

I also add a carbon fibre rod into the wing, in a crash the wing can split where the dihedral slits are made during construction, with a carbon rod in the wing it will NEVER break n matter how hard you crash!

I build the wing as normal and set the dihedral and then cut a slice into the underside of the wing, enlarge it enough for the rod then fill with hot glue and force the rod in and then i go over the top with more hot glue and scrape smooth.
Its hard to see in the photo because the wing is florescent orange but if you lok at the pic of the underside of the wing closely you can see the line where the rod has been put in.

The Cub can be so much more than the docile Trainer it is pitched as, its small enough to be agile but large enough to be stable and mine regularly fly's long distance and cloud surfs!

The most recent thing i have tried is running a 57.5" Storch wing on the cub and it has been a huge success, ive flown two days on that wing and although its been in stupid high winds, it shows a lot of potential for massively extending flight times and range and it flys very well too, landing speeds are way down from having so much lift!
The cub also looks huge once it has that wing on it

below are some pics of my cubs, some to show individual things ive done to mine including the Storch winged one

 

[Steve Fox]

Ok, so now some pictures on how to repair your cub/other fb plane if you have crashed it.

Just about anything can be repaired, this cub has already had the tail replaced but I recently had an 'interaction' with a power line and it brought me down onto concrete from about 265ft and the result wasn't pretty lol.

It's work in progress and I'll post more pics as the repairs are finished but here is the damage and the repairs so far.

First thing to do is make your replacement sections, you want to make them so they go further back than the damage.
Remove most of the damaged foam but don't cut it all the way back to good foam yet, we will do that in a second.

you lay the new part over the damaged area, line it up and cut behind the damage area though both the new pieces and the existing foam at the same time so you have lines that will mate when it comes to bonding it in.
This pic is from a previous repair as i forgot to take a photo this of this stage but its the same as what i did in this repair, all other pics are from this repair.

Here we have the nose after I layed the new parts over and cut though both

Now go inside the fuse and cut the power pod guides back by about 1", this will mean the new sections of power pod guides we glue in will overlap the outside nose joints and make it much stronger.

Here you can see a nose section bonded on and if you look, the power pod guide has its joint further back inside the fuse slightly and not on the same joint as the nose, it makes it much, much stronger

Now the other side:

I run a down facing camera as well as my forward one, so for easier access to re mount the camera I have bonded in the bottom of the fuse before I make the top part of the nose.

My bottom nose section also comes all the way forward and will have a \_/ shape cut in it to clear the esc when sliding the power pod in and out to change battery's and also supply some airflow to the esc, having this modified lower nose both improves aerodynamics and also provides a location for my down facing camera with a very small forward angle to it which is better for flying than directly down.

My bottom camera survived, just the outer lens got destroyed and so I just swapped the outer lens from spares I have and my focus remains set

So now we are up to speed on the repair so far.

Next up will be to cut the \_/ in the lower nose, bond the camera in, bond milk jug plastic to the underside for reinforcement as I belly land, add the top nose section and paint it all.

Then I'll re do the windscreen stickers and it will be time to try and save the wing which also took substantial damage.

I will post more pics as this progresses.

 

[OliverW]

Ok, so now some pictures on how to repair your cub/other fb plane if you have crashed it.

Just about anything can be repaired, this cub has already had the tail replaced but I recently had an 'interaction' with a power line and it brought me down onto concrete from about 265ft and the result wasn't pretty lol.

It's work in progress and I'll post more pics as the repairs are finished but here is the damage and the repairs so far.

View attachment 142163 View attachment 142162 View attachment 142160 View attachment 142159

First thing to do is make your replacement sections, you want to make them so they go further back than the damage.
Remove most of the damaged foam but don't cut it all the way back to good foam yet, we will do that in a second. View attachment 142169


you lay the part over the damaged area and cut behind the damage area though both the new pieces and the existing foam at the same time so you have lines that will mate when it comes to bonding it in.

Here we have the nose after I layed the new parts over and cut though both
View attachment 142170

Now go inside the fuse and cut the power pod guides back by about 1", this will mean the new sections of power pod guides we glue in will overlap the outside nose joints and make it much stronger.

Here you can see a nose section bonded on and if you look, the power pod guide has its joint further back inside the fuse slightly and not on the same joint as the nose, it makes it much, much stronger
View attachment 142171

Now the other side:
View attachment 142172

I run a down facing camera as well as my forward one, so for easier access to re mount the camera I have bonded in the bottom of the fuse before I make the top part of the nose.

My bottom nose section also comes all the way forward and will have a \_/ shape cut in it to clear the esc when sliding the power pod in and out to change battery's and also supply some airflow to the esc, having this modified lower nose both improves aerodynamics and also provides a location for my down facing camera with a very small forward angle to it which is better for flying than directly down.

My bottom camera survived, just the outer lens got destroyed and so I just swapped the outer lens from spares I have and my focus remains set

View attachment 142173
View attachment 142174

So now we are up to speed on the repair so far.

Next up will be to cut the \_/ in the lower nose, bond the camera in, bond milk jug plastic to the underside for reinforcement as I belly land, add the top nose section and paint it all.

Then I'll re do the windscreen stickers and it will be time to try and save the wing which also took substantial damage.

I will post more pics as this progresses.

That repair is so clean!!!!! awesome work. My cub repair was with 2 different types of foam lol

 

[Steve Fox]

That repair is so clean!!!!! awesome work. My cub repair was with 2 different types of foam lol

To, I've done this kind of repair before and it works well so thought I'd share it with others to show just about any amount of damage ot repairable

 

[BATTLEAXE]

You are the King of Cubs man, and the king of repairs as well. You did fine job, If my plane looked like yours did I would be building a whole new one. Lessons learned here

 

[Steve Fox]

You are the King of Cubs man, and the king of repairs as well. You did fine job, If my plane looked like yours did I would be building a whole new one. Lessons learned here

It's just experience, I've built so many cubs and crashed even more times that I have just got the hang of rebuilding them after big impacts.

Do you have proper templates?

For all my fb planes I make posterboard templates to make cutting out parts easy and accurate.
for the score lines I have made tiny little slits along the lines which I poke the sharp blade though In Several places along the the line and poke the blade though those holes when On the foam piece I'm making to create a dottedine which I then make a proper line with a blade and metal ruler by joining them up once the template is removed.

 

[IanSR]

Just out of interest @Steve Fox, how much heavier than a stock FT Cub is yours? I assume you're using White foamboard from hobbycraft?

 

[Steve Fox]

Camera secured and new front milk jug plastic bonded to the underside.

When it gets painted I will remove the outer lens from the cam which leaves a much thinner shaft to mask off and I'll stick the lens back off afterwards.

For those who don't know why I have a second cam facing down, I use it for keeping track of my ground position when at altitude, I have a switcher on-board and just flick between the two cams on a switch on my tx.

 

[BS projects inc.]

Working on a monster cub right now, roughly 250% sized. I have to make the wing tonight but that's it! I'll post a thread on the build when it flies.

 

[BATTLEAXE]

Working on a monster cub right now, roughly 250% sized. I have to make the wing tonight but that's it! I'll post a thread on the build when it flies.

That's one big Cubby, The C pack you have on there isn't going to fly it, is it?

 

[Steve Fox]

Working on a monster cub right now, roughly 250% sized. I have to make the wing tonight but that's it! I'll post a thread on the build when it flies.

What wingspan is that going to have, it's got to be in the 100" range?

Looks cool, I thought about building an oversized ft cub a few times bt have never bothered actually trying it.

The standard sized ft cub will fly well on a 57.5" ft storch wing, the lift it gives is considerably more than the standard 38" cub wing and it's a deeper wing from leading to trailing edge as well.
on a racerstar 2212 1400kv motor swinging a 9x5 prop with a 4200mah 3s and an all up weight of 1150g I managed a 35 min endurance flight cruising at around half throttle
It was the flight after that one where I had this crash and trashed the cub.

 

[BS projects inc.]

That's one big Cubby, The C pack you have on there isn't going to fly it, is it?

You would be surprised with what a c-pack can do. C pack should be plenty, the plane is very light and is going to have super light wing loading. The trust to weight ratio isn't what determines if a plane can fly. The motor has to overcome drag by a large enough factor to get the plane up to speed which isn't going to be much with a wing loading this light. Wingspan is going to be around 80-90 inches. Also this entire plane has been made with a 24" ruler and a sharpie!

If I am wrong entirely however I have a variety of motors to chose from that swing a 16" prop that can get this plane in the air.

 

[Steve Fox]

You would be surprised with what a c-pack can do. C pack should be plenty, the plane is very light and is going to have super light wing loading.

it will fly, you only need enough thrust to pull the plane fast enough forward for the wings to do their job and create lift.

my motor and prop combo creates 910g of thrust whilst having decent speed from a 1400kv motor, when I'm flying on a 2700 3s on a standard cub wing it weighs 890g so I have very slightly more thrust to weight but when on a 4200 it's 1100g and 1150 on a storch wing with that pack.

i believe that jumbo jets only have around 1/3 trust to weight, it's all about the type of flying you want to do, if you don't intend on fast climbs then you can get away with very low thrust levels!

one thing to remember with that giant cub is that it's also going to have a lot more drag for the motor and prop to overcome, it will fly but it may be slower than you expect.

 

[BS projects inc.]

it will fly, you only need enough thrust to pull the plane fast enough forward for the wings to do their job and create lift.

my motor and prop combo creates 910g of thrust whilst having decent speed from a 1400kv motor, when I'm flying on a 2700 3s on a standard cub wing it weighs 890g so I have very slightly more thrust to weight but when on a 4200 it's 1100g and 1150 on a storch wing with that pack.

i believe that jumbo jets only have around 1/3 trust to weight, it's all about the type of flying you want to do, if you don't intend on fast climbs then you can get away with very low thrust levels!

one thing to remember with that giant cub is that it's also going to have a lot more drag for the motor and prop to overcome, it will fly but it may be slower than you expect.

Looking for a big stol plane so all this sounds good with me!

 

[BATTLEAXE]

Looking for a big stol plane so all this sounds good with me!

Anything with a Storch wing is destined to be STOL. I look forward to see how this turns out

 

[Steve Fox]

Ok, I have some internal finishing to do with the power pod as it's a new one (re used the indestructible firewall) and need to permanently fix the esc to it, fit Velcro ect and I need to re install my vtx which is just a couple of cable ties but I have essentially finished the repairs and can now show the final cosmetics.
The motor was toast and that's new.

Let's remind ourselves what the damage was:

And now ladies and gentleman, I present to you, the cub reborn

Like I told 'Poormanrc' when he stuffed the nose on his, anything can be repaired and to a good standard

I could get airbourne straight away by using the old standard cub wing or even the new one i have for the GPS Cub but im gonna have a go at patching up the storch wing, if i cant save it then ill use the cub wing but start building a new storch wing as a 35min flight on a 50% throttle cruise and the shear amount of lift it has makes it my wing of choice for the cub now.

 

[BATTLEAXE]

Epi

Ok, I have some internal finishing to do with the power pod as it's a new one (re used the indestructible firewall) and need to permanently fix the esc to it, fit Velcro ect and I need to re install my vtx which is just a couple of cable ties but I have essentially finished the repairs and can now show the final cosmetics.
The motor was toast and that's new.

Let's remind ourselves what the damage was:
View attachment 142294

View attachment 142295
View attachment 142302
View attachment 142301
And now ladies and gentleman, I present to you, the cub reborn

View attachment 142296
View attachment 142303

View attachment 142297
View attachment 142298

Like I told 'Poormanrc' when he stuffed the nose on his, anything can be repaired and to a good standard

I could get airbourne straight away by using the old standard cub wing or even the new one i have for the GPS Cub but im gonna have a go at patching up the storch wing, if i cant save it then ill use the cub wing but start building a new storch wing as a 35min flight on a 50% throttle cruise and the shear amount of lift it has makes it my wing of choice for the cub now.

Epic repair job man. You can hardly tell it crashed. Good job

 

[Steve Fox]

Epi
Epic repair job man. You can hardly tell it crashed. Good job

Thanks, I've done So many repairs now that it's a process I'm familiar and confident in.
I've repaired other cubs many times but this one alone has had at least one new nose, I think two before this one!

I love foamboard planes, cut and shut jobs can be done quite effectively, no crash need write off a plane, anything can be repaired

 

[BS projects inc.]

Finished the wing yesterday! I plan on doing a maiden tonight, I'll be sure to upload a video!

 

[Steve Fox]

Finished the wing yesterday! I plan on doing a maiden tonight, I'll be sure to upload a video!

Looking forward to it!
try to get something we can all relate to size wise next to it In the video so we can get a feel for how big the cub is