Cox .01 /.02 /.05 /.09 /.15 Speed Planes

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Here are a few pics from when I was building it
I will take more of the next ones I build for sure.
The wing span of my nano is 20.5” with a root chord of 3.25” and a tip chord of 2.25”
wing is carved out of a sheet of 6.5mm light balsa and tapered to 3mm at the tips
And a semi semetrical airfoil

Excuse the messy work bench, I promise I tidied it all up before the maiden

Thank you Jordan, I could tell it had more wing span then the TD .010 as it must for the
weight of the Pee Wee. Yours glided well at that span a good wing for the .020 class speedy!
Good job on carving out the airfoil on the wing turn out to be a winner. When your TD parts
come in the mail I look forward to a big jump in speed post a vid for sure.

Have you had a chance to test fly / vid the 3 bladed prop?

Speaking of speedy I tested three props today in the field will post a vid, broke the carbon
prop screwed up on a dead stick landed by dirt and rocks. Another month or so the grass
will start growing again as it has been raining as of late.

APC 4.22 x 5.5 / 20,370 rpm static / 26,647 rpm unloaded to 139 mph prop speed.
Drone prop 4x5 / 26,347 static / unloaded to 29,887 rpm / 142 mph
I liked the thrust of the 4.22 x 5.5 although the drone prop did squeeze out more top end.

APC 4x6.25 Static 20,510 rpm but for some reason the recording stopped and I had no air time vid.
So a mystery as to just how fast it was going the engine died for some reason after a few laps I thought
I blew the plug but it started up just fine with the next prop. Perhaps I took in something into the carb
during flight like a bug lol.



Comes down to a choice to go open exhaust next to eek out some more power with the Cox engine.
It's about tapped out the plane floats in could clip the wings to 26" span if a dedicated Cox plane however
I plan to use other engines with higher power output The Fuji took the 32" span DART to 148 mph I think
it will hit 160 with the NANO III   Then there is the option to use a Norvel .061 next too will see.

Think I will give it one more chance open exhaust with SPI next. This 5.5P is loading the engine the scream
is not there but the speed is, best pass 26,485 rpm was sticking some good rpm this is mid way in the recording
when the rpm picked up it was rather rich at first. I will wav. scope the run and see what the Doppler program
results are. For a TD .05 it's a treat to see what's possible with modern gear to support it. If an all carbon plane
with 24" span could weigh a possible 7.5oz for a chance to hit 150.  Today was great for flying almost no breeze
but then no sun either, least no smudge on the camera lens today  

1440P HD vid:

Notice with speed and a rearward facing exhaust muffler the sound lags
the plane after it passes the camera unique with the TD RC version.

AmpAbuser
Published on Feb 10, 2018

NANO III / 9oz / 28" span / APC 4.22x5.5
Best pass 26,485 rpm / 138 mph prop speed
Static 20,370 rpm / 1oz fuel / 25% nitro / 20 castor

Checked all passes found the best per posted vid:
Per Audio RPM Gauge 26,647
Per Prop Calc 139 mph
Per Doppler Wav. Scope software 136 mph / 219 Kp/h

APC 4.22 x 5.5


Pass down wind 4 to 7 mph breeze, cloudy over cast hot humid from rains on Friday / Thurs.

There you go so far the fastest 3ch TD .050 RC pass to date perhaps in the world.
No one is going this fast with Cox .049 I have been keeping a lookout for other
speed freaks to make a Cox .049 plane with modern gear most just want to poke
around with vintage and sport designs. I think this is fun a real heart thumper for
small 1/2A and a good challenge to design them for straight line speed.    

Haha man that’s a tiny hole for a bug to get sucked into.
So today on my lunch break I tried out the racecraft 3x7.6 (I’m sure that’s advance ratio not inches of pitch?) still found the peewee didn’t have enough torque to overcome the big scoops in the prop. I managed to get a static reading of 17500rpm but it just couldn’t quite unload in the air.
Tonight I will try the gemfan. It’s a little lighter too so we’ll see

Also I can’t remember where I found this photo but has the anodising been removed from this engine or are there bare aluminium parts out there? I like it

Have you considered going with a Shuriken or other high output engine? I don't think the Cox 0.049's achieved anywhere near the output of that engine and apparently there are others even more powerful.

Jordan, do you like 20800 for your Pee Wee?

Jordan the Gemfan with a 5.2 pitch makes more sense to use.
A small IC engine just can't make good use with too much pitch no torque on tap like electrics.
But for sure the right dia. and 5 pitch does work.
Yes I removed the anodizing with sandpaper two grades then polished. The idea is direct
metal to air contact will help reduce heat better and allow you to run leaner for more rpm.

Jim I agree on better engines out there but the goal was to see what's possible
with Cox engines. Here is the short list with vids on my YouTube channel.
Really the trick is not taking the easy road with high priced engines or electrics.

Posted top speed vids thus far:
Cox .010 / 130 mph
Cox .020 / 106 mph
Cox .049 / 118 mph
Cox .050RC / 136 mph
Fuji .05 / 148 mph
Norvel .061 / 108 mph
SH .07 / 120 mph
Cox .09 / 144 mph

It does make more sense, however I tried it last night just before it got dark
And I had no speed difference between the gemfan and the racecraft and the 4.5x4 cox prop was still the fastest and ran the most reliable.
It seems the pee wee just didn’t have the torque to turn the three bladed props. They didn’t seem to unload in the air either
I am putting it down to my crappy fuel, I am down to the last 5% in the bottle so my guess is the nitro is all but gone, I’ll try both the props again on fresh fuel when i mix up some more.

Also I think I need to convert it to tee dee, after I find the max speed of a pee wee of course

Oh and can I sign up for one of those fancy backplates if there are any left

I sent a email to the machinist yesterday about those backplates hope he can
unload them soon as the requests have been mounting.

Bummer with those results I need to test my Cyclone 3 blade.
The Pee Wizzer reed induction engine is a fussy thing but with high nitro they
will sing. I have seen good results with 35% nitro 20% castor. The plane no
doubt needs thrust to go fast you want 1.5:1 whenever you can. But that's
not possible with the smaller engines. 60% thrust to weight ratio is bearable.
The TD retrofit will be the icing on the cake with that plane for now. If you use
a spring starter with the TD starting the striker props will be a cinch. They
have been the best for a good mix of thrust and speed as is in stock form.
E-Flite 4.5x4 cut down to 3.7x4 works well 87 mph static on a TD .02 / 4.6oz thrust.

I use a aluminum container system with my fuels large master containers made
out of spun aluminum for each fuel type holds 1/2 gallon each a quart container
of 35% nitro for the .01 and.02 engines, a 1/2 gallon of 25% for the larger
1/2A engines. A 1/2 gallon container for 60% nitro for boating projects and
a pint container for field use with 4oz and 6oz fuel tanks.

I use 4oz and 8oz fuel bulbs depending on 1/2A engine displacements for up to .09's
filled up and sealed tight for a day at the field. The trick is to minimize opening
the big containers take what I need then seal them up and leave them at home.
The precious nitro stays intact. I plan to buy another 1/2 gallon container for pure
nitro to top off field testing days over 100F as the nitro helps cool the engine.
I now have a fresh quart of pure castor on tap during this summer I will add a bit
more in my mix preferring 22% this summer. I will use a plastic pint container to
mix the days field batch during the heat of the summer. Any days under 85F can
get by with stock mix, last summer I ran in 108F with a heat index much higher.

Tested the 3 bladed Cyclone 3056
Best Peak 22,206 rpm / 2.6oz thrust / 118 mph / 37.3w
Good watt output and thrust for speed, fine for up to 4 oz plane.
Will unload to 25k easy enough 133 mph prop speed with a low
weight sleek racer. My 3ch Nano I weighs 3.6oz less fuel this
prop should take it over 120 mph down wind ground speed.



AmpAbuser
Published on Feb 11, 2018

Cox TD .020 / Cyclone 3 blade 3x5.6 / 22,206 rpm peak
Static best peak 2.6oz thrust / 37w / 118 mph pitch speed
Little tweaking needed yet but holds 21.5k easy enough 114 mph
25% nitro / 20% castor



3ch / 3.6oz NANO I

Good outcome with the cyclone prop

My mission tonight will be to go and find a nice aluminium bottle with a good lid that I can drill and put a pice of fuel tubing on the inside with an inline fuel filter, that way I can just use the syringe to pull fuel out and then pinch it off.
The bottle won’t be opened that way

I’ll treat it with some fuel with 35/20 nitro castor this time, I’m sure it will like it

Just put my order in for the bottom half of a tee dee from exmodelengines, so hopefully that will arrive in a week or so.

Also does the tee dee .020 have a thrust washer? Surly? I couldn’t find any on their website, I may have to make one if they are supposed to have them

So you got the  NV and venturi too and a plastic backplate just to get started.
Note a gasket for the Pee Wee works great to help seal the TD backplate.

No they do not come with a thrust washer I had to make mine out of thin tin from a pull
top lid from a food container.  

I use a aluminum fuel container as it will last the test of time and hold up to impact with
a robust lid.  The Cyclone prop seems like a winner for it's pitch if speed is wanted and
only 1oz plus fuel shy of a 1:1 thrust to weight ratio I can't complain. However for normal
sport flying it is always a plus to have unlimited vertical and more thrust into the wind.

I expect your Gemfan  3 blade props with the Pee Wee should improve with more nitro the
trick is to have enough rpm to up the thrust with it to make the pitch worth using

Oh.. nope I didn’t get a back plate :/ I might be able to get them to add it in before it ships.
I got a needle valve and Venturi though
I’m sure the extra nitro will make it sing

I’m tempted to build a version IV nano for the tee dee, with internal aileron push rods and a bolt on wing maybe a semi cowel to reduce the parasitic drag.

The pee wee is nice on this one, it’s nice to fly not to fast for the size, it’s a nice sport flyer and very maneuverable in a small space

Yes since it's the weekend he will add it in I imagine on Monday.

Your Pee Wee version was made for that amount of power out so just
getting a good prop and steady run will make it perfect.

A fancy version or Nanolux would be neat to do agreed, a cleaner aileron setup
cowling around the engine should add a bit more top end and glide. It took me
about 5 days building up the 1/2A version in the evenings the smaller ones go
a bit faster.

9.67oz with a Fuji 05 no pipe will just test it with the header and
see what numbers I get then fab a mount for the tuned pipe's stinger.
CG balances better with the extra .67oz on the nose. The 1oz tank
perhaps 5 mins. if left wide open.

Current standings with the engine and the 32" span DART 12.2oz on pipe:
148 mph / HQ Carbon blend 4045 / 36.75K
Minimum 34,730 to hit 148 due to plane size and weight it took more rpm.
With the much smaller Nano should get another 1k rpm down wind with a pipe.

Known stats 4045:
Static best peak 27.9k / 8.7oz / 134.3w / .180hp at launch 27.7k
1oz fuel tank almost all full throttle use gave 5:20 mins in total.

This should hit some heart thumping speeds, yet the engine is smooth like a sewing machine
easy on the air frame in those regards.

Talk about a speed freak
I guess a slow-flyer wouldn't satisfy??
They're some pretty big numbers.  Way too quick for my reaction time.

What a machine!

Tonight I mixed up a fresh batch of fuel and tried each different prop, my audio tach on my phone decided to work great too, I also got good readings from the hand held one.

The best I can get from the gemfan 3x5.2 static was 18550rpm it Unloaded in the air to about 21500rpm on the best pass

I also tried the umx striker prop which was surprisingly easy to start compared to last time, the extra nitro gave me a helping hand

The best static rpm from the umx prop was 19800  and it unloaded to around 22150

It seems like my needle is shifting after 30 seconds or so in the air, it just starts to go  rich and dies I have a spring off an .049 and fuel tubing over that but it just doesn’t make a difference, unless I start to get bubbles in my fuel line from the vibes?
I did notice it changes depending on the prop.

Anyway it was a fun evening tinkering with a few different props and fuel ect, next time I will try to get more videos  

Yes tinkering leads to successes and realizations of whats possible.
Good to hear the higher nitro is paying off for you. Perhaps if you run
it a bit lean on the ground in the air when it cools off it won't load up
too much.

Looking at the 3P Striker prop you must of saw some good thrust?
60 mph down wind passes are possible, perhaps you can figure out
how to hold some steady rpm with that NV. Spring with med size
fuel tube to help keep it sealed.

Monitor the hash mark on top of the NV thumb screw right before
you launch to see if it really is moving or cooling down in the air.

Okay I will try running it a little leaner on the ground next time, I already have a heavy duty spring with fuel tubing over it.
Ill also try keep an eye on the mark on top of the needle, I think it cooling down in the air is probably what is happening.

I have just started learning to use fusion 360 last night so I can 3D model some sleek fuselages, I do love balsa but I’m going to try a new method of construction.
I will 3D print a fuselage from a plastic that will dissolve in a solvent that way I can get a perfectly accurate form to vacuum bag I can the dissolve afterward, just like the lost foam method

I still like my balsa wings though, I think I still prefer shaping airfoils by hand after building competition hlgs since I was a kid.

My parts had already been shipped before I got a chance to email him back about adding a back plate, no drama though, I have access to a lathe I’m sure I can turn something up

This showed up today never flown no scratches mint amazing it has been
kept without even signs of fuel run up. I had one when I was a 11yr old
living in Holland, major memory high having one in my hands today.
This one would be good to copy as a wood built up RC plane.

Vintage 1970's COX SUPER SPORT TRAINER

This was my first and last COX model my father managed to get sneaked accross the Iron Curtain for me in 1974. I still have some fragments of it in my garage but the production engine with an 051 cylinder and white horseshoe backplate was lost for good on board a Lil Roughneck RC plane 3summers ago when the RX battery ran short of juice mid-air and I could only see it disappear behind a treeline....

Ahh man that bites but at least you had one and know how sexy they are.
This is my favorite racer type from Cox offerings, requires high nitro and a
perfect NV setting to get them cooking around.

I have been watching for a mint one on ebay for the last 3yrs.
Cost me $128.24 plus $16.14 to the front door just to see it again lol.
Keep an eye out on ebay you never know it can happen!

Brad you do not know how many times I was about to bid on the Super Sport Trainer on ebay but the shipping plus import duty always made it prohibitively expensive for me to buy but nostalgia will sooner or later get the upperhand on me and I know once I will have one again...this sexy bird is the culprit of me having become Coxaholic...