Re: COX .020 RC PROJECT

getback Wed Sep 18, 2024 5:55 am

Thanks for the reply TD I needed a good chuckle this morn. , sounds like what a country boy would do to me . Very Happy

Shame about the trees being cleared many many years ago my grandmother had some trees cleared for sale here on the 7 acres i am on now , still got a path through the woods big enough for a truck to get down . My new neighbor beside me cleared most of his 8 looks like landing strip Sad

Next time may want to consider a spinner rod and reel w/5/8 nut for weight we have done this to pull up a rope so we could pull a tree to the side when downing one as not to hit the building . Worked pretty good ... Yea shooting straight up not to easy now a days Old Bugger

TD ABUSER Wed Sep 18, 2024 9:29 am

getback wrote:Thanks for the reply TD I needed a good chuckle this morn. , sounds like what a country boy would do to me . Shame about the trees being cleared many many years ago my grandmother had some trees cleared for sale here on the 7 acres i am on now , still got a path through the woods big enough for a truck to get down . My new neighbor beside me cleared most of his 8 looks like landing strip
Next time may want to consider a spinner rod and reel w/5/8 nut for weight we have done this to pull up a rope so we could pull a tree to the side when downing one as not to hit the building . Worked pretty good ... Yea shooting straight up not to easy now a days

Yes I must have arthritis in my neck because I can hear bones cracking while flying overhead with control line. Both shoulders are arthritic too, so reaching up is difficult.
When I first moved to the woods 34 years ago I didn't even know how to keep a chainsaw running, split wood, do carpentry, masonry, plumbing, roofing, water well maintenance, etc.
You have 2 choices out here...either do the work yourself or hire others to do it for you.
I've seen City Dwellers try to make a go of it out here over the years and most go broke as land owners and move back to the Cul De Sac in Sardine-canistan. Laughing

I was able to recycle the wing dowels and the wire push rods...!
The wing was a pretty easy fix thanks to the OVERSIZED TRAILING EDGE holding it together.
I was out of that really nice transparent red and ended up using my life time supply of TowerKote red which is the ugliest shade of red they had [matbe that's why it was on sale.
After the repair I rebalanced the wing side to side with a scrap of thin tin scotch taped to the wing tip.
As for the CG the plane balances at the spar which is almost exactly 25% of the wing chord.
5 inch chord, 1 1/4" back is somewhere on the spar, but I'll tie on a hunk of solder to the engine to bring the CG just a wee bit more forward for the first flight.
I plan on using much less servo throw for the controls.
The first flight will be down at the bottom of the hill at one of the hay fields instead of in the backwoods of Washington.
Next plane I want to have ailerons.
Ailerons are a Lazy Man's way of forcing a crooked plane to fly straight as opposed to having just rudder and elevator.

TD ABUSER Sat Oct 05, 2024 8:11 pm

Here is the resurrected .020 TD Littlest Stick.

This time it is using the machined aluminum tank [is that a Kamtech item?]
What a masterpiece of machine work and design that tank is..!
It seems to hold about 1/2 ounce and my guess that is enough to make 20% nitro run for close to 3 minutes.
For me that's a really satisfying run time and having a built in tank makes scratch designing future planes for this engine that much easier.

This time the plane weighs 5.5 ounces which is noticeably less than the one that got stuck in the tree.
I used .031" piano wire for the pushrods instead of the .054" wire I used before.
Problem is, this lighter wire needs to be supported every 2.5 inches [my opinion]
The model flew today perfectly with no need to retrim the radio. The amount of down thrust and right thrust that Dave Fritzke Plan Service called for was spot on.
With the black Cox 4 x 2 prop the vertical climb was almost straight up and the model was super maneuverable without being the least bit twitchy.
Next time I go flying I'll take a video.

1/2A Nut Sat Oct 05, 2024 11:11 pm

Hi Chuck, good to see you getting after it.

Bernie carried them, red and silver, here is mine being tested.

Jun 24, 2018
TD .020 CNC Fuel Tank Test / 3.75 x 3 Prop
Best peak to 21,074 rpm
Calc. at 20,994 rpm / 3.94oz thrust / .039hp / 29w /60mph PS

Small Cox Logo

TD ABUSER Sun Oct 06, 2024 2:19 am

1/2A Nut wrote:Hi Chuck, good to see you getting after it.

Bernie carried them, red and silver, here is mine being tested.

Jun 24, 2018
TD .020 CNC Fuel Tank Test / 3.75 x 3 Prop
Best peak to 21,074 rpm
Calc. at 20,994 rpm / 3.94oz thrust / .039hp / 29w /60mph PS

Howdy Brad.
The field down the hill from my house that I flew at was taken away from me for a couple years so that millions of dollars worth of rock and dirt could be trucked in to raise much of the 10 acres about 3 feet. Now it is up for sale so I can sneak out there with a little plane once in a while until it gets sold.
The fuel tank is a really impressive piece of work and amazing it can be sold for such a low price.
What's the trick to keeping the .020 intake stack tight...?
What's the lightest you go with music wire control rods...?

1/2A Nut Sun Oct 06, 2024 4:32 am

My engine is all aluminum, can get the cnc carb body here:
Cox .020 Tee Dee Airplane Engine Carburetor Carb Body 020
EX Model Engines

https://www.ebay.com/itm/282104214204?_skw=.020+carb+body&itmmeta=01J9GH0TZCB1PFQJ0BYA2TYK7R&hash=item41aeb8b2bc:g:hzkAAOSw9GhYjj~1&itmprp=enc%3AAQAJAAAA0HoV3kP08IDx%2BKZ9MfhVJKkdhEXKit7VFPT48q9IbLWo6jxq97uaazfYvMB%2F04q2e9dpjvIGsT7twDSNMWpFQ0JEGiDu6iGBFvSrWBQzVm5ZkkDvfVOTBu7F7g2anGVWIaMvedV4Wb3eUFq1cnmp1rgV4pHvWj3nydnFCWkr4vP6Yd1%2B35TKPvwF9uZDO9slsksDFjKgPQ3x94amtpjopVc0mxzUmvjQAj%2FhGHCR8obVMwZOWuNrZYsqhg0sGRT4xFM2wuUaBUJeGB4lc7qbEPg%3D%7Ctkp%3ABk9SR-avg5HMZA

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If you desire the spring starter use then go with Cox International version here has the post:

https://coxengines.ca/cox-020/cox--020-carburetor-body-round-red.html

Can guide the piano wire with bulkheads and some small nylon tube.
Carbon rod is the clear winner for the lowest possible weight with resistance to flex.

My lowest 3ch TD .020 project thus far:

Jan 26, 2024
Cox Tee Dee .020 All Aluminum Crank Case- RC Throttle Sleeve
3rd channel add to Nano design. Has a CNC milled backplate.
20% Castor 25% Nitro rpm check 3.75 x 3 prop.
This one has been shined up to match the wing and horizontal stab.
Cool factor 10. RTF weight 102.3g or 3.61oz
Very fast, out of site performance freight train in any direction.

Small Cox Logo

TD ABUSER Sun Oct 06, 2024 7:51 pm

1/2A Nut wrote:My engine is all aluminum, can get the cnc carb body here:
Cox .020 Tee Dee Airplane Engine Carburetor Carb Body 020
EX Model Engines

I picked up a couple of those carb bodies.
Do they need a sealant ..? [I don't like using sealants]
I guess "tightness keeps things tight" when it comes to some things like threaded air intake stacks. Just check it after every flight until it "takes a set".
I used to safety wire my precious KK NVAs to the engine.
Looks like your .020 NANO plane should be able to do it all at 3.6 ounces..!

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If you desire the spring starter use then go with Cox International version here has the post:

https://coxengines.ca/cox-020/cox--020-carburetor-body-round-red.html

Can guide the piano wire with bulkheads and some small nylon tube.
Carbon rod is the clear winner for the lowest possible weight with resistance to flex.

My lowest 3ch TD .020 project thus far:

Jan 26, 2024
Cox Tee Dee .020 All Aluminum Crank Case- RC Throttle Sleeve
3rd channel add to Nano design. Has a CNC milled backplate.
20% Castor 25% Nitro rpm check 3.75 x 3 prop.
This one has been shined up to match the wing and horizontal stab.
Cool factor 10. RTF weight 102.3g or 3.61oz
Very fast, out of site performance freight train in any direction.

1/2A Nut Mon Oct 07, 2024 12:26 am

Yes the plane did 130mph 4pitch prop down wind with a TD .010
- now eats through head winds equally fast with the TD .020.

Proper tools and cold oiled threads is my trick along with micro sized crescent wrenches for the venturi.
- hot set checks is a must along with balanced props and bench testing to sus out leaks and fits.
- nothing fancy just oil and tight fit. Yes gets locked in after a few hot / cold phases.
- I hate to mar with improper or poor fit tools.

Small Cox Logo

rdw777 Mon Oct 07, 2024 8:37 am

Glad you got it going TD….It’ll scream with that TeeDee on it!!!….. Love the stitched hinges…. Looking forward to the video !!

Always like to see what you’ve got going too Brad, Impressive!! Thanks for sharing all the data goodies…. Interesting!!

1/2A Nut Mon Oct 07, 2024 12:20 pm

rdw777 wrote:
Always like to see what you’ve got going too Brad, Impressive!! Thanks for sharing all the data goodies…. Interesting!!

Thank you Robert, happy to share!

Small Cox Logo

TD ABUSER Mon Oct 07, 2024 8:58 pm

Here we go.....as promised ....a Littlest Stick video...!
sorry about the camera work.
Maybe the lens just needs a good cleaning...?
There is almost enough power to maintain a hover...! Cool

I've got the controls and the CG set very conservatively so the plane is most likely not as snappy as snappy can be.
At any rate this was a good plane to get myself a sense of scale for what size and weight limits a .020 model design should fall into if it's going to have "sporty performance"..instead of the first plane I designed that would have needed 2 or 3 more 020s bolted to it to be considered "sporty".. Laughing

1/2A Nut Tue Oct 08, 2024 2:49 am

Flew great with the stock 2P prop. What is the RTF?

Small Cox Logo

rdw777 Tue Oct 08, 2024 9:21 am

Excellent TD!!…. Groove’s well and excellent piloting…. Very nice power to weight ratio…. Quite peppy!!…Will be very aerobatic…. One of my favorites is to take it up to spec height and pull the stick into the bottom right corner…. Spins muy pronto!!….. Keep us updated as you get acquainted with TeeDee .020 Ace LS Small Cox Logo

TD ABUSER Tue Oct 08, 2024 11:22 am

1/2A Nut wrote:Flew great with the stock 2P prop. What is the RTF?

It's 5.5 ozs..and that includes cross grain balsa fuselage sides [1/16" sheet doubled] from the firewall to the back of the wing saddle.
Not needing a separate fuel tank and using the wimpiest music wire control rods [.031"] is what "added lightness".
This iron on covering is pretty light too. The wing by itself weighs almost nothing.

I'm still using 9 gram servos though.
Have you run across micro servos that are too light / weak for what we do...?

TD ABUSER Tue Oct 08, 2024 11:30 am

rdw777 wrote:Excellent TD!!…. Groove’s well and excellent piloting…. Very nice power to weight ratio…. Quite peppy!!…Will be very aerobatic…. One of my favorites is to take it up to spec height and pull the stick into the bottom right corner…. Spins muy pronto!!….. Keep us updated as you get acquainted with TeeDee .020 Ace LS

Thanks..!
As you can see I'm pushing my luck flying there. So much traffic and the field is a MINE FIELD of ruts and rocks under the clover
The nearest club field is about 10 miles away...I guess it's time to join and "go get legit".

I need to make the control throws you saw my LOW rate instead of HIGH rate if I want to make this LS as much fun as yours...!

Note to self...I need to look through my Cox stuff for a .020 rod reset tool.
I would imagine the .020s don't need to be reset as often as the .049s...?

rdw777 Tue Oct 08, 2024 4:28 pm

I get it about the rough field, Mine is similar…. But you’re at a good weight to not be coming in to fast…. Mine weighs just about the same…. Lighter weight helps them survive better….

Photo below shows max throws….When you get a chance try to fly it inverted…. For a non aileron plane works surprisingly well….Lots of down elevator..,,Three mistakes high for me… Very Happy

TD ABUSER Tue Oct 08, 2024 4:59 pm

rdw777 wrote:I get it about the rough field, Mine is similar…. But you’re at a good weight to not be coming in to fast…. Mine weighs just about the same…. Lighter weight helps them survive better….

Photo below shows max throws….When you get a chance try to fly it inverted…. For a non aileron plane works surprisingly well….Lots of down elevator..,,Three mistakes high for me…

Thanks for showing me how much control throw you use....nothing too extreme there, I'll set mine to match yours.
Yes I discovered how "locked in" it flies inverted [a big surprise] and it also does square corner loops better than any control line plane I've flown. Lightness prevents the unwanted inertia.

I haven't found out yet what the time limit is for inverted flight with the built in tank.

I can now see that if you built in enough stab incidence to make the model do big loops when allowed to fly straight ahead....that "rudder only single channel" flight was much more doable than what I thought when I first heard of it.

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