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Aug 28, 2020, 06:50 PM
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Would not be scale


The original does not have flaps but then again this thing is "stand WAY off" "scale"

Did not do it on mine but kinda regret it now so yea if your tx ect supports so manny channels then go for it.
Best to assign a channel to each servo so you can also keep the flaps working as ailerons.
That would also allow fun things as "crow" mixing (flaps down ailerons up) as speed brakes.

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Aug 28, 2020, 07:13 PM
Entropy is happening!
Jim.Thompson's Avatar
Quote:
Originally Posted by cmulder
The original does not have flaps but then again this thing is "stand WAY off" "scale"......................
I have no scale intentions or aims anyway.

Quote:
Did not do it on mine but kinda regret it now so yea if your tx ect supports so manny channels then go for it.
Best to assign a channel to each servo so you can also keep the flaps working as ailerons.
That would also allow fun things as "crow" mixing (flaps down ailerons up) as speed brakes.
.................
That's a good tip CM, thanks.
I like Aileron to Flap mix at circa 30% on my sailplanes. I'll do the same with this one.
So............flaps it will be!......................
Aug 28, 2020, 07:24 PM
Registered User
racer256's Avatar
Quote:
Originally Posted by JimG2
Having built and flown one, powered by sc48 four stroke, I can say that this is not suitable as a trainer. The take off is scale with a tendency to swing that has to be caught with rudder.

Jim
Thanks for the response Jim🙂. Whenever we do go back to the WPAFB in Dayton, I'll make sure to take pics.
Aug 29, 2020, 04:35 PM
Registered User
jgg12002's Avatar
Quote:
Originally Posted by PookaHat
Yep
Sep 03, 2020, 07:12 PM
Entropy is happening!
Jim.Thompson's Avatar

Undercarriage suspension modifications.


I lightened my landing gear and modified it.
If the springs shown in the picture turn out to be too light or soft, I have some continuous lengths of smaller springs that will fit inside these and be tensioned as required.
No weight yet, but will weigh them when I take them off this set up board.
Last edited by Jim.Thompson; Sep 05, 2020 at 08:00 PM.
Sep 09, 2020, 12:09 PM
Registered User

Nice!


Nice work and I love the design. It may not be very scale looking but I think it looks cool as hell! I would think you have as much time in modifying/making the landing gear as you would in building the plane.
Sep 10, 2020, 07:14 PM
Entropy is happening!
Jim.Thompson's Avatar
Quote:
Originally Posted by rch37
Nice work and I love the design. ............................
Thanks. I have now made the tail wheel assembly after much deliberation of how to build it. The kit instructions are missing some vital details and it seems to me the tailwheel was originally meant to be mounted on the rudder. This is very poor mechanical design in my imagination.
The arrangement I have arrived at will work ok I think.

Quote:
It may not be very scale looking but I think it looks cool as hell!...........................
I am not into the scale look part of the hobby; I care only if the model flies well and looks ok.

Quote:
I would think you have as much time in modifying/making the landing gear as you would in building the plane..................
Probably so; the assembly of the well designed and laser cut ply, balsa and pauwlonia parts was easier than putting together a big jigsaw puzzle. I am accustomed to building self designed, scratch built models, so this was like "having a holiday" from usual demands on body and mind!.....................

The pushrod driving the steerable tailwheel is spliced onto the main rudder pushrod inside the fuselage.

I will be working on the covering next; tail surfaces have already been done. I will use 30 micron laminating film and paint it.

Jim.
Sep 12, 2020, 07:23 PM
Registered User
I cut flaps and covered it as light as I could, Micafilm on the open bays. My take, compared to other cubs? This is a heavy model. 6+ pounds all up, maybe 5.5 pounds without the flaps. I like them light. I take the wheels off in storage, to keep from developing flat spots on the tires. The plans, huh? What plans?
Last edited by Bleu; Sep 12, 2020 at 07:29 PM.
Sep 12, 2020, 08:00 PM
Entropy is happening!
Jim.Thompson's Avatar
Quote:
Originally Posted by Bleu
I cut flaps and covered it as light as I could, Micafilm on the open bays. ...................
What is this "Micafilm" please Bleu?

Quote:
....................This is a heavy model. 6+ pounds all up, ......................
Wow! That is 2.7 kg. in our measurement system.
Has it flown yet?
Nice build by the way....................
Sep 13, 2020, 12:05 AM
Registered User
Micafilm is a light weight covering material with no glue backing. You need to apply an adhesive on the model frame, old style, then iron on. It came in different colors including primer grey. It hasn't flown yet, my field is out of service, not enough people to keep the weeds down .
Sep 14, 2020, 03:46 PM
Registered User
Gualtie's Avatar
Quote:
Originally Posted by JimG2
Having built and flown one, powered by sc48 four stroke, I can say that this is not suitable as a trainer. The take off is scale with a tendency to swing that has to be caught with rudder. Turns must be made with rudder and aileron to look OK. Otherwise it flies well and lands well, the undercarraige though appearing crude works well. I hold the wings on with a bolt through the fuselage into a captive nut in the wing root, the hatch in the roof is removeable for access to the bolt. I did modify the starboard door to open like the full size but there is not enough wood in the fuselage to make the door the correct size and it is too small. Overall a kit that is easy to build and can be easily improved with a little work, a good flier for a pilot with some flying experience.

Jim
hi mate,
I'm building the v 2, the one with more scale door and the screws around windows.
some parts are not existing within the "instructions" and "plan"...
do you have an idea of these parts placement?

any other suggests from anyone?
thanks
Oct 22, 2020, 10:49 PM
Vertical Unlimited
Straight Up's Avatar
Quote:
Originally Posted by Jim.Thompson
I am at the stage I will have to choose wether or not to cut the ailerons in half to make flaps/ailerons, or to go with just ailerons.
My flying buddies who have these advocated the fitting of flaps.
Not sure yet.

Jim.
I'm just finishing the kit version of this plane (box of wood, no covering). The use of flaps will help avoid floating on landings (Cubs are notorious for this) but the fullsize J3 never had flaps (its successor the Supercub did). Depends if you want to keep it "scale". I've not fitted flaps.
Oct 22, 2020, 10:50 PM
Vertical Unlimited
Straight Up's Avatar

CG position?


I'm just finishing my Cub. The instructions I have say to cite the CG at 70mm back from the leading edge (LE). This seems a bit far forward to me. The mainspar is 90mm aft, ad that's where I'd expect to balance. While a forward CG is safe for flying, it can make landings a pain, whereby you "run out of elevator" before the craft is below min flying speed, resulting in bouncing.
Oct 23, 2020, 12:58 AM
Entropy is happening!
Jim.Thompson's Avatar

CG position.


I have just finished my HobbyKing J3 Cub too.
I have yet do a final check of the CG, but I will be setting it back around the spar position. I don't like a forward CG.
I am just waiting for a receiver to come from Hong Kong.

I think the weight is around 2.8 kg with a 3000 4 cell LiPo fitted! I will check again now all it done.

Edit: Checked!

I have a Turnigy G46 outrunner in mine driven with a 4 cell and using a Turnigy Plush32 60A ESC.
13 x 6 prop on it now. I have a 12 x 8 drilled and reamed to fit ready to try too.

Otherwise, ready to fly.

Jim.
Last edited by Jim.Thompson; Oct 23, 2020 at 02:41 AM.
Oct 23, 2020, 10:29 AM
Registered User
E-Challenged's Avatar
Adding flaps to this already weighty model is unnecessary and will make it's stall speed higher. I have a Sig J-3 Cub, electric powered , no flaps. With 71 inch wingspan, it weighs about 6 lbs with two 2200mah lipos side by side, in parallel. High wing models with tail-wheels all need rudder and elevator input while taking off to keep straight and prevent turning left. They also need coordinated rudder and aileron input to make graceful turns free of "adverse yaw". Adverse yaw is where the drag of the down going aileron, resists turning in the desired direction. IMHO adding flaps including two servos and linkage adds weight and is unnecessary and is non-scale. Flaperons on a Cub-like model may interfere with aileron effectiveness and are normally used on gliders. I use rudder/aileron mix on a switch or do it manually. Proper "tail-dragger" techniques for Cubs are explained in a number of You Tube videos. Learning "tail-dragger" technique is useful for flying warbird and other models with "conventional landing gear". I wouldn't recommend the 1/6 scale Sig Cub to a beginning builder, the design, plans. and instructions are "old school" not as beginner friendly as larger Sig Cubs and the kit does not include a dummy engine. Picture is my Sig 1/6 scale Cub.


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