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May-2022
1/2A Nut's

"Tee Dee .020 RC"



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Post  Tobaiies Sun Apr 24, 2022 1:48 pm

I saw some small speed models in a forum. I found the topic very interesting and wanted to try it.
I printed out photos from the forum and used them as plans.

Cox PeeWee Micro Speeder Img_2012
Cox PeeWee Micro Speeder Img_2011
Cox PeeWee Micro Speeder Img_2014
Cox PeeWee Micro Speeder Img_2013



I'm quite happy with the shape, but unfortunately I didn't had any other covering film.  Laughing

Cox PeeWee Micro Speeder Img_2015
Cox PeeWee Micro Speeder Img_2020
Cox PeeWee Micro Speeder Img_2019
Cox PeeWee Micro Speeder Img_2021

It flies amazingly well and its a lot of fun!

.

sry for the bad quality Sad
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Post  balogh Sun Apr 24, 2022 3:55 pm

You have completed it very well and it flew beautifully...what happened with the fuselage, was it broken on landing? If the battery is not fixed and the landing is hard, the battery goes like a loose cannon and may destroy the bulkheads and the entire fuselage...
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Post  Tobaiies Sun Apr 24, 2022 4:05 pm

balogh wrote:You have completed it very well and it flew beautifully...what happened with the fuselage, was it broken on landing? If the battery is not fixed and the landing is hard, the battery goes like a loose cannon and may destroy the bulkheads and the entire fuselage...

Thanks Smile
No, I'm not sure if the model undercut (is that how you say it in English?) or if I was just too slow to react. It went pretty quickly into the ground, but is repaired and flown again.Cox PeeWee Micro Speeder Img_2022
Cox PeeWee Micro Speeder Img_2023
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Post  balogh Sun Apr 24, 2022 4:13 pm

At less than 100 grams it is very light and must glide very well, so I do not think it stalled. I did not see the end of the flight, but if you land in headwind with some "up" elevator, then it should not land diving head-on into the ground..
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Post  Tobaiies Sun Apr 24, 2022 4:22 pm

balogh wrote:At less than 100 grams it is very light and must glide very well, so I do not think it stalled. I did not see the end of the flight, but if you land in headwind with some "up" elevator, then it should not land diving head-on into the ground..

By undercutting I mean when the wing creates downforce instead of lift at high speeds. so not when landing. Unfortunately, I don't know the English term for this.
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Post  balogh Sun Apr 24, 2022 5:23 pm

In tail wind or at too low speed the lifting force on the wing is reduced. The uplift will not be sufficient to keep the plane gliding.. This is called stalling..
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Post  1/2A Nut Sun Apr 24, 2022 5:49 pm

Congratulations on getting some flying fun in!  Thumbs Up

Is the vid showing the plane flying with a Cox 4Dx2.5P prop?
What is the wing span and size battery are you using?

To help avoid tucking / diving with your current sheet wing there are some options.
- shim the wings leading edge up at the wing saddle to induce positive incidence.
- move the wing forward to increase tail moment distance and reset CG.
- set up for a slight forward CG to improve horizontal stabs elevator + pressure influence on the wing.

For sheet wings I always set up with a semi symmetrical airfoil that graduates to a fully symmetrical at the wing tips.
Incorporate washout at the wings trailing edge sanding it in to improve stability further and low air speed control.  

Fireworks Thumbs Up Small Cox Logo Thumbs Up Fireworks
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Post  getback Mon Apr 25, 2022 6:28 am

It seem to fly pretty well , was that the maiden flight ? 1/2A Nut knows his stuff when it comes to speed , he has done a lot of it in builds and videos . sunny Good to see you were able to fix back quickly hopefully you can get the glitch fixed for many more flights cheers I Love This Forum!
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Post  Tobaiies Mon Apr 25, 2022 12:35 pm

1/2A Nut wrote:Congratulations on getting some flying fun in!  Thumbs Up

Is the vid showing the plane flying with a Cox 4Dx2.5P prop?
What is the wing span and size battery are you using?

To help avoid tucking / diving with your current sheet wing there are some options.
- shim the wings leading edge up at the wing saddle to induce positive incidence.
- move the wing forward to increase tail moment distance and reset CG.
- set up for a slight forward CG to improve horizontal stabs elevator + pressure influence on the wing.

For sheet wings I always set up with a semi symmetrical airfoil that graduates to a fully symmetrical at the wing tips.
Incorporate washout at the wings trailing edge sanding it in to improve stability further and low air speed control.  

Fireworks Thumbs Up Small Cox Logo Thumbs Up Fireworks

Thank you!
yes, its a 4Dx2.5P prop. I use a 1s 260 mAh LiPo and the wing span is 57cm.
I had no more problems on the last flights. I think it was just me. Paranoid
But I've also thought about the angle of incident.
Thanks for the tips, I will implement them when building the next model!
I try to record a video with better quality and speed on wednesday. Very Happy
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Post  1/2A Nut Mon Apr 25, 2022 7:08 pm

Great to hear you can get some HD vid Thumbs Up


I use SIG airfoil shaped balsa wood planks and modify from there.


Cox PeeWee Micro Speeder Imag0611


Note the sanded airfoil wing tip has washout incorporated.

Cox PeeWee Micro Speeder Imag6412

Small Cox Logo RC Plane
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Post  davidll1984 Tue Apr 26, 2022 6:36 am

Cool this Litle plane Small Cox Logo Babe Bee .049 RC Plane Is that it's just me that this model reminds of the gupy The fuselage in particular
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Post  Tobaiies Tue Apr 26, 2022 7:33 am

davidll1984 wrote:Cool this Litle plane Small Cox Logo Babe Bee .049 RC Plane  Is that it's just me that this model reminds of the gupy The fuselage in particular
I took a quick look, you're right.
Didn't know the model before and just used the form from the forum. But it's practical to fit everything in the narrow fuselage.
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Post  1/2A Nut Fri Apr 29, 2022 1:14 am

Any word on getting a HD vid?  RC Plane


Here is one of my .020 planes.



Cox TD .020 / 3.37x4.5 Prop / bull nose prop tips.
Needed back cut on the prop blades to increase rpm with
more tapper prop tips and increased dia. to 3.5 x 4.5N  
3ch throttle sleeve, 4.2oz RTF / 19.5" Span / 43 sq. in.
Plywood fuselage with spruce stringers in the corners.
Has taken full throttle hits into the ground no breakage.


Small Cox Logo  Thumbs Up
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Post  Tobaiies Fri Apr 29, 2022 4:21 pm

1/2A Nut wrote:Any word on getting a HD vid?  RC Plane


Here is one of my .020 planes.



Cox TD .020 / 3.37x4.5 Prop / bull nose prop tips.
Needed back cut on the prop blades to increase rpm with
more tapper prop tips and increased dia. to 3.5 x 4.5N  
3ch throttle sleeve, 4.2oz RTF / 19.5" Span / 43 sq. in.
Plywood fuselage with spruce stringers in the corners.
Has taken full throttle hits into the ground no breakage.


Small Cox Logo  Thumbs Up

It was too windy on Wednesday, but today was good. Here is a video with better qualtiy.


Plus one from a Delta with .049 Graffiti Bee.
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Post  davidll1984 Fri Apr 29, 2022 7:59 pm

This is the first time i se one of those graffiti bee runing sound Good near the tee dee rpm sound Small Cox Logo Babe Bee .049 RC Plane Thumbs Up
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Post  1/2A Nut Sat Apr 30, 2022 3:24 am

Thank you for sharing, the engine was running a bit better up to 19.3k rpm observed  Thumbs Up
Very good glide with the all metal weight of the Pee Wee.  
4x2.5 prop / 16,876 rpm at launch / 3.17oz thrust / 16w / 40mph prop pitch speed


I have an example with a TD 020 it uses the same Cox 4D x 2.5P prop.
Static 17,603 rpm / Best pass unloaded 25,579 rpm / 61 mph prop pitch speed



Jul 12, 2014
Cox TD .020 / 3ch Lil Speedy 1 / Cox 4x2.5 Prop
25% nitro / 21in. span with exhaust throttle sleeve
Plywood rolled fuselage, balsa foiled wings.

Small Cox Logo Thumbs Up
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Post  Tobaiies Sat Apr 30, 2022 9:37 am

1/2A Nut wrote:Thank you for sharing, the engine was running a bit better up to 19.3k rpm observed  Thumbs Up
Very good glide with the all metal weight of the Pee Wee.  
4x2.5 prop / 16,876 rpm at launch / 3.17oz thrust / 16w / 40mph prop pitch speed


I have an example with a TD 020 it uses the same Cox 4D x 2.5P prop.
Static 17,603 rpm / Best pass unloaded 25,579 rpm / 61 mph prop pitch speed



Jul 12, 2014
Cox TD .020 / 3ch Lil Speedy 1 / Cox 4x2.5 Prop
25% nitro / 21in. span with exhaust throttle sleeve
Plywood rolled fuselage, balsa foiled wings.

Small Cox Logo Thumbs Up
Thanks! Very Happy
what kind of propeller would you recommend me? Something like an APC?
At a certain point the engine just won't rev up any further.

I have two Tee-Dee's .020 and one .010 in the original box. I'm tempted to try one, but they're too good for me.
Although they are made to be used. Huh...
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Post  1/2A Nut Sat Apr 30, 2022 5:11 pm

To gain same prop rpm,
-Seal the NV with fuel tubing to hold a steady peak
-Smaller sleek plane effort, enough for a safe fast landing no more
-If with a PeeWee best with a remote 1/2oz tank and horse shoe backplate.
-Higher nitro
-Turbo plug adapter from Kamtechnik.com

The plane design was meant for performance, your choice of wingspan at 47cm / 22.44in is big for all out speed with a PeeWee.
The spans lift allows trick flying with some speed at 3.2oz RTF. Given the wings performance envelope prop choice can vary.

Prop mass, design, drag and stiffness control what's possible. The stock cox props at 2P and 2.5P limit top end speed to save
enough engine power set aside for thrust. Must consider total load on the engine counting the plane design for best prop match.  

To gain a good leap past old school speed performance the prop choice must start with at least a 3P.
To get there a 3.75x3 stock E prop works well found as a replacement prop for the Stryker.

E-Flite EFLUP037503 Prop/Propeller 3.75 x 3: Ultra Micro F-27Q Stryker
Cox PeeWee Micro Speeder Eflup010

The strength is enough to spring start and fly with care no mods needed as is.
Big thrust gain due to prop design allowing increased rpm and more speed.
I have hit 92 mph pitch speed with a TD .020:

First test vid with the 3.75x3 prop

Lil Speedy II / TD .020 / 29,554 RPM / 84 MPH / Throttle Sleeve

-----

Best possible props always require modification to get top end speed or max thrust.  
I have tested the HQ 4x4.5 carbon blend prop stock and modified with good results.
Flight tested strong enough as a stock prop up to TD.051 to 33.1k - / Fuji .05 to 36.4k rpm

Another prop with a mix of speed and thrust.
APC 4x3.3E prop nice low weight and no bulky type fuel engine blades.
Stronger design stiffer blades but require modified blades to work with a .020 engine.  
Requires back cut of the blades to reduce load. For more top end rpm reduced to 3.6 x 3.3N
3.6 x 3.3N / TD .020 / 22,300 rpm static / 4.6oz thrust / 39w / 70 mph prop pitch speed / unload est. 95PS

Below the blade has some back cut but could do with further modifications per yellow lines to improve speed.
Cox PeeWee Micro Speeder 20220410


The IC APC 4.2x2 is way too beefy -heavy / over kill for a .020 and requires mod to gain rpm / speed.

Cox PeeWee Micro Speeder 20482010

Bench tested - TD .020 / OS RP4 Turbo Plug
Peak 22,206 rpm 42 mph prop pitch speed - per prop calc 6.7oz thrust / 37w
The blade was modified to keep the diameter for higher thrust gain thru added rpm.

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