HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Feb 02, 2012, 02:37 PM
I prefer Deans
Phaeton's Avatar
Netherlands
Joined May 2006
1,218 Posts
Carbon Cub SS as a model - thoughts

Since the model is almost finished and ready to fly, here are my thoughts so far already.

Carbon Cub SS as a model

Pro's:
  • Very good looks, especially because the fuse is diamond shaped. The middle of the fuse/cabin, horizontally seen, is wider then the top and bottom, giving it a more dynamic and modern appearance.
  • Has the good old J3 flight characteristics. At least. In theory I'll have to see what mine does

Con's:
  • CoG far forward and short nose. Hard to balance.
  • Complex cowl, it takes non-rc techniques to create one.

Building with carbon

Pro's:
  • More strength with less volume/mass opposed to balsa.
  • Very quick to assemble. Once you figured out where to put what…
  • Looks good after covering has been applied, very thin contact surfaces.
  • Looks also good before covering is applied.
  • Very solid.

Con's:
  • Dust when using tools like a Dremel.
  • More expensive (when it matters).
  • When using this size of carbon tubes, 2mm, special attention has to be given to the joints to make them durable.

Lessons learned
  • When using carbon, a substantial weight reduction can be achieved. But stay consistent. I didn't. Applying balsa or even plywood can neutralize the effect quickly. See my battery tray, that should have been based on carbon tubes as well. Kind of sleigh. Same for the ply to which the servo's are attached.
  • You have to have the less is more thought active during every building step. Only then the plane will end up light. I didn't, so I'll end up with an auw of about 680 gram / 23.98 oz. My previous estimate was wrong...
  • Especially on this model, anything in the tail must weight almost nothing to get it balanced without counter weight in the nose. The rudder was ok, the horizontal surfaces should have been build the same way. The balsa I used here made the tail to heavy. However:
  • These 2mm thin and open surfaces are very hard to attach covering material to. Hardly any "meat" and to thin, covering material tends to stick to the covering material on the other side to quickly.
  • Resulting in messy and visually less appealing work.
  • It is better to use 2mm depron in the three tail surfaces and cover it with self adhesive covering material that doesn't need heating (depron kind of melts).
  • About the wings: Way to much balsa mass. See post #145, the ribs should have been like that. In the store, a 2mm balsa sheet looks thin enough. On the workbench, it is almost massive. You can go thin almost to the extreme, strength is achieved with the proper "construction" method.
  • This model is 10th scale. It should have been 8th scale while using the same 2mm carbon tubes. More advantage from the weight savings, bigger wing area (lower wing load) and a bit more room (and alternative placing possibilities) for equipment. As Cabledawg1 mentioned in the beginning of this thread. Servo's can remain the same and - in my case - the motor as well. Only with a 9x4 prop then. Larger ground clearance.

For now?
  • The detail finishing on the outside could be better. Covering, windows (except for the wind screen) and some edges. But I'm very content with the overall shape and looks.
  • Put a tmp cowl on and see how she flies.

Only if I'm happy with the results, and I have the feeling there is room for improvement, I'll take my time to:
  • Get me a "real" Carbon Cub SS cowl.
  • Replace the three tail surfaces with 2mm depron ones. To reduce weight here and therefore also reduce counter weight in the nose.
  • Take all the covering off, select another brand and go for perfection this time
  • Rebuild the wings with the ribs as shown in post #145.
  • Rewire the wings with wiring from which the insulation has been removed. That stuff is heavy.
  • Assemble new flaps and ailerons, less massive.
  • Redesign the flap and aileron hinge mechanism. Make it invisible this time.
  • Order the new E-Flite UMX Carbon Cub SS to fly a CC anyway while this one is in the hangar
  • Consider building the Bobber.

That should save weight considerably, bringing the auw down to the level that is possible when building with carbon and improve the looks.

And now I'm off, carbonizing my Mac



Yvo

.
Phaeton is offline Find More Posts by Phaeton
Last edited by Phaeton; Feb 02, 2012 at 03:10 PM.
Reply With Quote
Sign up now
to remove ads between posts
Old Feb 02, 2012, 05:26 PM
There is Victory in the Lord!
knifeedge63's Avatar
United States, GA, Locust Grove
Joined Feb 2011
842 Posts
get some pics up of whucha got so far!
knifeedge63 is online now Find More Posts by knifeedge63
Reply With Quote
Old Feb 03, 2012, 05:26 AM
I prefer Deans
Phaeton's Avatar
Netherlands
Joined May 2006
1,218 Posts
Ok, this is what we've got so far...

Yvo

.
Phaeton is offline Find More Posts by Phaeton
Reply With Quote
Old Feb 03, 2012, 06:38 PM
There is Victory in the Lord!
knifeedge63's Avatar
United States, GA, Locust Grove
Joined Feb 2011
842 Posts
cool!! get that cowl on her!
knifeedge63 is online now Find More Posts by knifeedge63
Reply With Quote
Old Feb 04, 2012, 08:26 AM
I prefer Deans
Phaeton's Avatar
Netherlands
Joined May 2006
1,218 Posts
Quote:
Originally Posted by knifeedge63 View Post
cool!! get that cowl on her!


Although it will be a temporary cowl, it must have some looks. Alignment with the spinner o.a.. I finally found a spinner small enough (1") and it's in the mail now. Probably arrives by the end of the upcoming week.

Considering the weight, I'm probably a bit low with my 2s powerplant and try to get the max possible thrust (an 8" prop is the limit - ground clearance) by switching from an 8x4 prop to an 8x5 prop. An 8x6 is to hot and a three-blade not efficient enough.
And the 8x5 is in the mail as well. Actually three of them.

So I guess that cowl is on and the plane balanced and ready to fly next weekend, but then we have to wait for suitable weather. But the lipo's are fully charged already

Yvo
Phaeton is offline Find More Posts by Phaeton
Reply With Quote
Old Feb 04, 2012, 09:37 AM
There is Victory in the Lord!
knifeedge63's Avatar
United States, GA, Locust Grove
Joined Feb 2011
842 Posts
Quote:
Originally Posted by Phaeton View Post


Although it will be a temporary cowl, it must have some looks. Alignment with the spinner o.a.. I finally found a spinner small enough (1") and it's in the mail now. Probably arrives by the end of the upcoming week.

Considering the weight, I'm probably a bit low with my 2s powerplant and try to get the max possible thrust (an 8" prop is the limit - ground clearance) by switching from an 8x4 prop to an 8x5 prop. An 8x6 is to hot and a three-blade not efficient enough.
And the 8x5 is in the mail as well. Actually three of them.

So I guess that cowl is on and the plane balanced and ready to fly next weekend, but then we have to wait for suitable weather. But the lipo's are fully charged already

Yvo
You sound relatively prepared! haha I cant wait!!
knifeedge63 is online now Find More Posts by knifeedge63
Reply With Quote
Old Feb 15, 2012, 09:37 AM
ich bauen groß modell flugzeug
Keenan smith's Avatar
United Kingdom, London
Joined Dec 2010
6,831 Posts
I'm watching for the maiden
Keenan smith is offline Find More Posts by Keenan smith
Reply With Quote
Old Feb 15, 2012, 10:25 AM
I prefer Deans
Phaeton's Avatar
Netherlands
Joined May 2006
1,218 Posts
Quote:
Originally Posted by k.smith459 View Post
I'm watching for the maiden
The video will eventually be there Still waiting for the spinner to arrive. After that it's the cowl and after that it's waiting for decent weather...

I'm curious, she's heavy after all...

Yvo
Phaeton is offline Find More Posts by Phaeton
Reply With Quote
Old Feb 15, 2012, 02:32 PM
ich bauen groß modell flugzeug
Keenan smith's Avatar
United Kingdom, London
Joined Dec 2010
6,831 Posts
nice
Keenan smith is offline Find More Posts by Keenan smith
Reply With Quote
Old Mar 24, 2012, 03:47 PM
Go Ducks
RexSe7en's Avatar
United States, OR, Milwaukie
Joined Feb 2012
136 Posts
Have you been able to get her out for the maiden yet? I can't wait for some updates!
RexSe7en is offline Find More Posts by RexSe7en
Reply With Quote
Old Mar 24, 2012, 04:16 PM
I prefer Deans
Phaeton's Avatar
Netherlands
Joined May 2006
1,218 Posts
Quote:
Originally Posted by RexSe7en View Post
Have you been able to get her out for the maiden yet? I can't wait for some updates!
Nope...

Although weather is becoming very nice, sun and almost without wind, no maiden yet. Still don't have a cowl... Was a bit busy with other things, amongst others an upside down apartment, looking for a broken water pipe somewhere in the concrete between my kitchen and the bathroom. Messy

The only update (this week) is the 3 blade GWS HD 8x4 prop...

But no worry, maiden and the respective movie will be there

Yvo

.
Phaeton is offline Find More Posts by Phaeton
Reply With Quote
Old Mar 24, 2012, 06:28 PM
Go Ducks
RexSe7en's Avatar
United States, OR, Milwaukie
Joined Feb 2012
136 Posts
Sorry to hear about the broken pipe! A broken pipe can be bad enough, but in concrete! Now that is always beyond dreadful! Hopefully you get that all worked out here before long.

Do you have a game plan for the cowl? I know you had touched on it a few times earlier in the thread, but just wondering what you decided on, if anything yet. The 3 blade prop looks great and a bit more oomph is always a plus

Keep us posted, I'm itching for some updates!!!!
RexSe7en is offline Find More Posts by RexSe7en
Reply With Quote
Old Mar 24, 2012, 06:47 PM
I prefer Deans
Phaeton's Avatar
Netherlands
Joined May 2006
1,218 Posts
Quote:
Originally Posted by RexSe7en View Post
Sorry to hear about the broken pipe! A broken pipe can be bad enough, but in concrete! Now that is always beyond dreadful! Hopefully you get that all worked out here before long.

Do you have a game plan for the cowl? I know you had touched on it a few times earlier in the thread, but just wondering what you decided on, if anything yet. The 3 blade prop looks great and a bit more oomph is always a plus

Keep us posted, I'm itching for some updates!!!!
Thanks

Long story short, the water is fixed, the kitchen (and the neighbours below me) are dry again...

I guess I stick to my original plan, q&d cowl and when the Cub flies well enough, I'll make the "real" cowl.

For now then: Balsa (easy to work with) mold and vacuform the thing and paint it black. That should do it.

I'll post the progress

Yvo
Phaeton is offline Find More Posts by Phaeton
Reply With Quote
Old Apr 05, 2012, 01:27 PM
I prefer Deans
Phaeton's Avatar
Netherlands
Joined May 2006
1,218 Posts
Floral foam

One thing missing: A temporary cowl.

Bought a brick of floral foam today. The sturdy grey type, not the green stuff. The latter dents already when you even look at it.

It shapes easily, so making a mold for later vacu-forming should be easy. Hope to get things done this weekend.

Yvo

.
Phaeton is offline Find More Posts by Phaeton
Reply With Quote
Old Apr 07, 2012, 09:06 PM
Go Ducks
RexSe7en's Avatar
United States, OR, Milwaukie
Joined Feb 2012
136 Posts
Well I'm happy to hear that everyone is dry once again. I'm also happy to hear that progress is being made on the cowl and that we may soon have a maiden report!
RexSe7en is offline Find More Posts by RexSe7en
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion 6-foot scale INDOOR Piper Cub scratchbuild Michael in Toronto Scratchbuilt Indoor and Micro Models 70 Aug 15, 2014 12:28 PM
Build Log Winter project - Piper PA-18 Super Cub - Ed Westwood plans - Scratchbuild Phaeton Parkflyers 152 Apr 13, 2013 01:31 PM
Discussion STOL Super Cub HUMPHREY1957 Scale Fuel Planes 9 Jun 22, 2011 08:25 AM
Question Carbon wing strut construction (HZ Super Cub) themicahmachine Beginner Training Area (Aircraft-Electric) 3 May 12, 2011 06:16 PM
Discussion new puppy in the kennel: aeroworks 165" span carbon cub balsabozo Scale Sailplanes 15 Mar 18, 2011 08:40 AM