Super Cub Upgrades

[GordPayne]

New member here.

My uncle gave me a used Hobby Zone Super Cub to learn with.

It seems to have had a rough life. Would conk out with thermal protection after just a couple of minutes of flight.
The wing also has no ailerons which was less than ideal.

I have replaced the brushed, geared motor with a brushless motor (2836 1120kV) with a 40A ESC. I found a motor mount file on Thingiverse that I 3D printed and reinforced with fibreglass and epoxy. We'll see how resilient it is.

I got a new wing, took some dihedral out of it (but not all) and put in a couple of carbon fibre strips to strengthen it.

There's some lead in the nose to restore the cg.

I never liked the battery box being so close the the huge prop. So there's a switch harness underneath so I can install the battery without it going live before I'm ready.

I'm quite pleased with the upgrades. I'm looking forward to Frank giving it a first flight once the warmer weather arrives.

[Frank v B]

Gord,

First of all...welcome to TEMAC. 
Love your tag line.  (Old Buttonville proverb,"If you have to hit the fence, hit the far fence, not the near fence.").

This plane is designed for about 100 watts of power.  That motor is about 300 plus.  It's about avoiding shredded foam.
Two cautions for the maiden flight:
- Limit the power. Either limit the throttle on your transmitter if you have a 3-cell pack or start off with a 2 cell battery pack which reduces max power by 1/3.  I would start off with a prop with no more than a 4" pitch (Lower pitch gives better vertical, not speed.  Higher pitch gives more speed, less vertical).  Increase power/pitch to your liking after the maiden flight.
- Re-enforce the firewall.  They use a gum-type glue (the brown glue in the photo) that tends to let go.  Add some of your favourite glue in the open spaces.  Also, drill some holes through the plastic firewall and insert round toothpicks with some glue and push them about an inch into the foam.  Once the glue dries, cut off the extra toothpick lengths with side cutters.

Maiden flights are unforgiving.  I try to set up a plane so it can take off and land safely and get the feel of an airplane (conservative power, conservative throws).  Within 10 seconds it will be easy to tell which adjustments are needed.  The mission is to get the chance to make these adjustments.

For what it is worth.

Frank

ps: let me know if you need to a different prop (I have 150 plus!) or borrow a 2 cell battery pack for the maiden flight (indicate connector).

[GordPayne]

Thanks for the advice Frank. I have some smaller batteries for sure. 

I'll reinforce the firewall as you suggest.

I have a couple of different props to try.

Motor is big as I expected. Not experienced enough to know all the calcs.  I can always use the motor on a bigger plane in the future.

I thought I'd design a little bracket to limit the throttle on the Tx.

We'll do a responsible progressive approach.

Will be great!

"Keeping the blue side up and the green side down" 

[Frank v B]

Gord,

No need to change the motor, just de-tune it for the first flight.  From experience, swapping a brushless motor for the original brushed motors usually creates CG issues.  A brushless motor of equal power weighs about half as much*.  A larger brushless motor adds nose weight and solves a CG issue.

There is a quote "always overpower a model airplane.  You can always throttle back....if you have to!   

re: your quote "Keeping the blue side up and the green side down".... that doesn't help a colour blind and brain-dead sod installer. 

Frank

* when I converted a Great Planes 72" span Siren from brushed to brushless only a 28 mm  diameter outrunner like yours would fit inside the carbon fuse.  I lengthened the nose by 2" and still had to add nose weight.  It still drags its rear end in a turn.

[Gregor77]

Ok, I am going to give one input.

The alerions are a great idea, but you need to put the hinge closer to the pivot point.  So that the connector hole is right on the pivot point.  With it being that far back, it might cause for additional stress on the servos.  So just more the control horn closer to the pivot point.


Also the plane is designed to be a 3 channel, it will somewhat fight you to fly level or not... lol!

[GordPayne]

Thanks for the suggestion Gregor. Much appreciated.

[Gregor77]

Like all the members!  We are just full of knowledge and other stuff! 

[Gregor77]

I think they also made a float kit for that plane, around $20 or more if I recall.  Its a fun plane for off the snow!