The Sliver - a TD .020 Project

Tee Bee wrote:Doesn't this just look like a Mauricio airplane?

Hello Tee Bee !, that model looks great! .... has a very good line! ... you have thought how you are going to decorate ?, (colors ??)...Monokote?

That looks really NICE am glad to see you're back at it !! Oh Tee Bee , i don't get over to RCGroups that much and would bee easier if you can post a link, Thanks!! That plane has got a signature for sure .. Flight report !!

Steve and I have agreed that the plane would look good in a Russian-like scheme. Currently thinking about white with some red stars and graphics, somewhat Yak-ish.

Getback , here's a link to the build thread. I hope it works.

http://www.rcuniverse.com/forum/1-2-1-8-airplanes-70/11640642-sliver-build-thread-td-020-project.html?styleid=6

Tee Bee wrote:Steve and I have agreed that the plane would look good in a Russian-like scheme.  Currently thinking about white with some red stars and graphics, somewhat Yak-ish.

that's going to look great ... what flight time does the Tee Dee 020 give you with your original red tank?

About 2 minutes. Yes, longer flights would be nice but this is a much simpler setup. My LaStick is set up the same way. Once I get it tuned, I usually fly/refuel several times in a row. An external tank can always be added later but space is a premium with the battery and radio gear and I want to keep it light.

Great looking plane, Tee Bee.

In my small R/C planes powered by 010 and 020 engines I use small party balloons for a tank placed in the nose of the plane, to extend the flight time to about 8-10 minutes. The small balloon efficiently fills in any compartment unlike a heavier plastic tank....so I just tell you this idea to about it.

Tee Bee wrote:About 2 minutes.  Yes, longer flights would be nice but this is a much simpler setup.  My LaStick is set up the same way.  Once I get it tuned, I usually fly/refuel several times in a row.  An external tank can always be added later but space is a premium with the battery and radio gear and I want to keep it light.

of course, it happens to me that I like to fly at least about 6 minutes per flight, otherwise when you start to enjoy , you have to land to replenish fuel ....

balogh wrote:Great looking plane, Tee Bee.

In my small R/C planes powered by 010 and 020 engines I use small party balloons for a tank placed in the nose of the plane, to extend the flight time to about 8-10 minutes. The small balloon efficiently fills in any compartment unlike a heavier plastic tank....so I just tell you this idea to about it.

András, I know that you use balloons as a fuel tank, (I never use one), my questions are:
what kind of material is the globe? common type of birthday ??
what size balloon?
used double? ... to prevent any puncture?
How long does the balloon have before it degrades?
Have you ever pinched one inside the model by escaping the fuel?
I am going to thank you for your experience in using this method ...

Hi Mauricio,

the balloons I use are common birthday or party balloons sold by gift shops in very small to large sizes. The one I use on small engines like 010 and 020 may have a 20 ccm unpressurized volume, the Cosmic Wind driven by the 090 has a volume of around 80 ccm unpressurized capacity. I fill up the small ones with some 10..12 ccm fuel, and the large ones with 60 ccm.

I only fill up the balloon until it starts pushing the fuel into the engine, pressurizing them by extra amount would cause a very rich initial run in a moment (launching the plane) when otherwise maximum power is needed.

The precautions I do to prevent fuselage damage if the balloon gets punctured is coating the inside of the fuel compartment with a paint that resists nitro, and prevents the balsa from soaking up the fuel. It is sold in spray bottles

Inside the tank compartment, and especially behind the firewall where the engine bolts protrude from the nuts I cover all sharp edges to prevent balloon puncture in case a nose -down, unwanted landing. In the past 7 years of my R/C plane history I punctured only 3 or 4 by an unplanned landing that burst the balloon open. This is the only risk balanced, by the ease and convenience of its use, no need for a heavy clunk and an open vent line, etc...

These balloons do not quickly decompose in contact with nitro, I only saw some decompose if left in a plane not in use for a long period...then the balloon collapses and the internal surfaces stick together. If you place the balloon into the plane to allow easy removal, then you can always check it for its integrity.

I've been intrigued with balloon tanks for some time but I have yet to try one. Seems that most of my planes end up needing some noseweight anyway to balance, so that hasn't been a big issue. I've been able to make reliable clunk lines by using tubing with adequate flexibility and making some custom clunks that are heavy enough to scavenge all the fuel. I'm a bit lazy and once I find something that works for me, I tend to stick to it. For my .010 and .020 planes, that same laziness has resulted in using the traditional backmounted Cox tanks, forcing me to live with the short run times. I'm even guilty of using a Black Widow in it's stock form on several occasions, though the .049 Surestart I'm going to fly tomorrow on my Minnie Mambo has a 2oz round Sullivan tank which can run 15 mins easily. There is certainly more than one way to skin a cat and I might feel froggy enough someday to step out of my comfort zone and put a balloon in one of my models. When I want to see how all the local guys set up their 1/2A models, I simply look in my garage because I'm the only one around for many miles that I know of. That's another reason I

balogh wrote:Hi Mauricio,

the balloons I use are common birthday or party balloons sold by gift shops in very small to large sizes. The one I use on small engines like 010 and 020 may have a 20 ccm unpressurized volume, the Cosmic Wind driven by the 090 has a volume of around 80 ccm unpressurized capacity. I fill up the small ones with some 10..12 ccm fuel, and the large ones with 60 ccm.

I only fill up the balloon until it starts pushing the fuel into the engine, pressurizing them by extra amount would cause a very rich initial run in a moment (launching the plane) when otherwise maximum power is needed.

The precautions I do to prevent fuselage damage if the balloon gets punctured is coating the inside of the fuel compartment with a paint that resists nitro, and prevents the balsa from soaking up the fuel. It is sold in spray bottles

Inside the tank compartment, and especially behind the firewall where the engine bolts protrude from the nuts I cover all sharp edges to prevent balloon puncture in case a nose -down, unwanted landing. In the past 7 years of my R/C plane history I punctured only 3 or 4 by an unplanned landing that burst the balloon open. This is the only risk balanced, by the ease and convenience of its use, no need for a heavy clunk and an open vent line, etc...

These balloons do not quickly decompose in contact with nitro, I only saw some decompose if left in a plane not in use for a long period...then the balloon collapses and the internal surfaces stick together. If you place the balloon into the plane to allow easy removal, then you can always check it for its integrity.

Thanks András for all this information, it really is very interesting.
Thank you for answering my doubts and I see that based on what you say, you have ample experience in many cases. I had not thought of an emergency landing with impact! ... it is still a pending issue in me, to do at some point this type of installation.

Tee Bee wrote:I've been intrigued with balloon tanks for some time but I have yet to try one.  Seems that most of my planes end up needing some noseweight anyway to balance, so that hasn't been a big issue.  I've been able to make reliable clunk lines by using tubing with adequate flexibility and making some custom clunks  that are heavy enough to scavenge all the fuel.  I'm a bit lazy and once I find something that works for me, I tend to stick to it.  For my .010 and .020 planes, that same laziness has resulted in using the traditional backmounted Cox tanks,  forcing me to live with the short run times.  I'm even guilty of using a Black Widow in it's stock form on several occasions, though the .049 Surestart I'm going to fly tomorrow on my Minnie Mambo has a 2oz round Sullivan tank which can run 15 mins easily.  There is certainly more than one way to skin a cat and I might feel froggy enough someday to step out of my comfort zone and put a balloon in one of my models.  When I want to see how all the local guys set up their 1/2A models, I simply look in my garage because I'm the only one around for many miles that I know of.  That's another reason I

Personally for me it is also a pleasure to be able to share in this forum so many experiences of different people that right here we are from different parts of the world.
As I once told András, how good it would be at least once to share with all the guys at CEF a meeting!

That would be fun, Mauricio.

Tee Bee wrote:That would be fun, Mauricio.

and do not miss the beer! Yes, I like it but I do not abuse it ...

The closest I have experienced to a Cox enthusiast gathering is my trips to the SMALL Fun Fly in Little Rock, Arkansas. My son and I have been 5 times and always enjoyed it. Though most of the models flown there are electric powered these days, there is a definite die-hard crowd of Cox engine enthusiasts who attend. RC, FF, and CL are represented well. Lots of flying, laughing, and camaraderie between friends who enjoy the same thing. That event helps keep me motivated to keep building so I can take something new to fly each year. It is definitely worth the 500 mile driving trip each way to go!

Tee Bee wrote:The closest I have experienced to a Cox enthusiast gathering is my trips to the SMALL Fun Fly in Little Rock, Arkansas.  My son and I have been 5 times and always enjoyed it.  Though most of the models flown there are electric powered these days, there is a definite die-hard crowd of Cox engine enthusiasts who attend.  RC, FF, and CL are represented well.  Lots of flying, laughing, and camaraderie between friends who enjoy the same thing.  That event helps keep me motivated to keep building so I can take something new to fly each year.  It is definitely worth the 500 mile driving trip each way to go!

here in my country a few years ago existed a meeting of model airplanes with Cox engines, there was a house of aeromodelismo representative of Cox, the house turned 60 years and very recently closed its doors, I have a friendship with its owner and instead when he calls me and says: I found a Cox accessory, do you want it?! .... URGENT I say!
There is also a unique mini-event meeting, but for work reasons I can not go, I have busy weekends with my work, but it does not mean that I can participate at any time.
Meanwhile I enjoy in my club these little models of their own, some afternoons of flight, where nostalgia, memories and imagination give me much pleasure in flying these little wonders .... like this old Cox, which I recovered from an aeromodelista, I bought it, I restored it and it flew again!

Some progress on the Sliver.  Aileron torque rods assembled.  Made a removeable hatch for the fuel tank compartment.  Covered the tail pieces and wings with Ultracote Lite Scale White.  All hinge slots cut, hinges installed and glued.  Used mylar cut from old floppy discs to make them and glued with thin CA.  Made a canopy from .008" Lexan sheet. Tinted it darker with a hot solution of black Rit fabric dye. TD .020 stock fuel tank removed and switched out for a backplate mount.  This gets the engine closer to the firewall for better aesthetics and will have a longer runtime with a 1/2oz fuel tank in the fuselage.  Should be good for 5-6 minutes of flight.  

Servos mounted. Pushrods and control horns getting fitted. Inching forward.

The engine is ready to go. Feast your eyes on the mighty TD .020RC!

That's the ticket Troy, great micro RC effort!

I thought you might approve.

Next transition is the spinners, flat head screws mare, flare out and tend to do the screw driver slip etc.
Worst of all the likely hood of the prop flying off is great as you can't stay constant, they bolts will
bend and flex some as spinner migrates due to over bore.  

Solution that has never lost a prop / spinner yet is the hex head bolt you can fell it squeezing down
the compression, warp / flex free tension as you rotate that alan wrench.

I have not tried the button head type yet aerodynamics is always a plus starting at the spinner to feed
that prop clean air. Always strive to buy the half threaded bolts if possible the extra meat fills the void
in the spinner's bore. There is slop causes vibrations you can see the spinner wobble, I can't stand it.

One way around that is to use TD .010 spinners and tap them for #3-48" x .75" all threaded bolts.
What you get is instant increase in rpm / vibration free through the entire throttled rpm range.
The lower mass also aids in rpm / thrust. As shown on the far left I have used a standard button head
slotted bolt and use the bench grinder to shape to fit / contour of the spinner.  All subject's shown in the pic.
No slop means no vibrations / excessive wear to the aluminum crank case bore for the crank.
I tap and thread the TD .020 spinners for my TD .049's #5-40 hex bolts yields zero spinner migration.
Spinner dia. is important to prop hub dia. some prop hubs are just too big.  I prefer to use props that
match the prop thrust plates.