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Oct 11, 2014, 02:55 PM
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nnChipmunk v2


RELEASE
nnChipmunk v2 | RC Foam de Havilland DHC-1 Chipmunk (3 min 46 sec)


CHASE
nerdnic | nnChipmunk v2 Chase RAW (8 min 13 sec)


BUILD VIDEO
nerdnic | nnChipmunk v2 BUILD (1 hr 57 min 50 sec)

nnChipmunk v2 Plans

DETAILS
Hi friends.

I am really excited to release the nnChipmunk v2 to all of you! The original nnChipmunk was my favorite plane to fly, hands down. This is a sentiment that many of you have shared with me as well over email, here on the boards, and in person. To me, it was the triumphant design that stood tall above the rest. Every time I took it to the field someone would be amazed to learn that it was made from simple dollar foam. The nnChipmunk v1 bridged the gap between "oh that's a scratch build? Yeah.. I could tell" and "Wait, you made that? That plane is cooler than my store bought!" Even though it's not my most flashy, popular, or best looking design, it is still my favorite.

With that said I am happy to announce that starting in July 2016 the nnChipmunk v2 will be available for purchase in kit form!
EDIT: Build Kits are now available!

New features in v2:

HATCH
-Updated version of nnP-39 style hatch

v3 SPEEDWING
-New custom airfoil that's SLICK (no FT style 'steps')
-More streamlined version of a clark y airfoil
-All planes I release with the v3 speedwing will have the same airfoil
-Easier to build

NEW BASIC WING
-Same airfoil as v3 speedwing
-Thinner profile
-Basswood spar
-Can handle 500w of power vs 350w on normal FT style basic wing

TAIL FEATHERS
-Double layer foam
-Added airfoil

CANOPY
-Added canadian canopy (featured)
-New 'framing' technique

GENERAL
-Wing notches to fuse cleanly
-Fuse length slightly reduced to allow for kit creation
-FT power pod and new nerdnic pod compatible


If you like this design then perhaps you’ll like some of my others as well.








SPECS
WINGSPAN
43in | 1100mm

FUSE
30in | 762mm

CHANNELS
4

WEIGHT
Airframe - 305g

ELECTRONICS
Basic
MOTOR - Turnigy D3530/14 1100kv
PROP - 9x6 APC
ESC - Dynam 30a
BATTERY - 2200mah 3S
SERVOS - 4x 9g


Speed
MOTOR
-Tacon Big Foot 10 1100kv 1100w
-NTM 3548 1100kv
PROP - 10x10 APC
ESC - 80a Dynam
SERVOS - 4x 12g metal gear
BATTERY
120 MPH - Heavy Duty 3300 4S
85 MPH - Zippy 2200 3s 40c

BUILD DIFFICULTY
Beginner – You’ve never flown a plane before, let alone done a scratch build
Novice – You’ve flown a plane but have no experience with scratch building
Intermediate – You’ve flown and built a few FT style planes before
Advanced – You’ve mastered the standard FT build style and are looking for a new challenge
Expert – You’ve mastered all build techniques and aren't afraid to improvise or tackle tedious builds

This is a intermediate to advanced build.

PILOT SKILL
Intermediate

MATERIALS
6 BBQ skewer
3 sheets DTFB
1 flat aluminum 1/16" x 1/2" x 24" (speedwing)
1 Basswood 1/8" x 3 x 24" (basic wing)
1 sheet poster board
1 2 liter bottle
Push rods
Control horns
Hot glue


FAQ
Is the v2 a swappable?
It will accept a FT power pod as well as a new pod I have designed. The new pod is larger to accommodate a bigger battery.

Is this a good plane for a beginner to fly?
No. The nnChipmunk v2 is a bit too advanced for a beginner.

Can I build the basic wing without the basswood spar?
I would not suggest this. The basic wing is much more advanced than a standard FT style fold over wing. Some of these improvements create weak areas that need to be reinforced.

Can I build the speedwing with no aluminum?
No.

How come no flaps?
After testing the plane thoroughly I am confident it simply doesn't need them.

There is a plane I want you to design, what’s the best way to suggest it to you?
Please use the request form here on my site.


PICTURES























































Thanks for checking out the nnChipmunk v2! If you built a v2 and enjoyed it please consider donating a few bucks so I can buy more supplies to make more great planes.











================================================

v1 - The below data is for the outdated version of this design

================================================



MAIDEN FLIGHT


nnChipmunk - Maiden Flight | FREE PLANS (4 min 22 sec)






80+ MPH

nnChipmunk - 80+ MPH | FREE PLANS (2 min 45 sec)


Last edited by nerdnic; Mar 26, 2018 at 04:01 PM.
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Dec 18, 2014, 03:07 PM
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nerdnic's Avatar
Updated plans to include Super Chipmunk tail feathers.
Mar 16, 2015, 11:23 PM
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nerdnic's Avatar
Had fun flying my nnChipmunk today.

(0 min 4 sec)
Feb 07, 2016, 04:44 PM
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nerdnic's Avatar
Started work on a v2:

Feb 07, 2016, 11:09 PM
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Lawn Dart Flyer's Avatar
Is version 2 a speed wing?
Feb 07, 2016, 11:56 PM
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nerdnic's Avatar
It has both :-)
Feb 08, 2016, 05:15 AM
Registered User
This is awesome work. Engineering and workmanship.

A small request for future - an Embraer Tucano looks much nicer

http://www.combataircraft.com/aircraft/TEMB312_vl.jpg
Feb 08, 2016, 02:15 PM
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nerdnic's Avatar
Thank you! I think that would make a great model plane, definitely on my list!
Feb 09, 2016, 11:55 AM
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Apphoard's Avatar
Nice looking plane Nerdnic, I plan to build one hopefully soon. Once I get a little better at flying. Definitely by spring. Sorry if I missed it in video or somewhere, but what setup do you have in that 80+ Chipmunk? Is it a 4s or 6s, mah? Motor and esc size ? Thanks for the info, just wondering how to push it that fast and keep it flying good. Also what size aluminum spar do you have? I am sure cf would work also, correct?
Feb 09, 2016, 03:41 PM
Registered User
nerdnic's Avatar
Hi there,

Here is what i'm running on the 80+ build:

MOTOR - NTM 35-48 1100kv (173g 1000w)
PROP - 10x10 APC
ESC - Dynam 80a
BATTERY - 3000 40c 4S
SERVOS - 4x 12g metal gear

With the alum spar the wing holds up really nice at any speed. I've built bigger, heavier, faster planes using the same alum spar and have never had a failure, even when trying.

The flat alum I use is 1/2" high 1/16" wide and comes in 3ft length. If you have a home depo or lowes around you, they should carry it for a few bucks. CF will work but you have to make a dihedral center piece. A bent nail or some other coupling should work.
Feb 16, 2016, 08:11 AM
Registered User
Hey Nick.
In order to make the spar you need to take the flat rectangular aluminium spar and cut it into a triangular shape? And you glue it flat to the spar - right?
Have you thought about using alum tube and pre-bend it to make the correct dihedral?
It could be encapsulated inside a box-type-spar?
Feb 16, 2016, 12:20 PM
Registered User
nerdnic's Avatar
So I actually just cut a straight line about halfway into the spar. Then as you bend to close the gap left by the hacksaw blade, you get a few degrees of dihedral. I think if you have the right tools to stretch and compress the aluminum this would be a better route. A tube will definitely work though it will be heavier.

The single piece of flat aluminum is already so strong that adding extra weight, even if the benefit is extra strength, just isn't necessary. I mean you're talking about a wing that weighs less than a half a pound and can support almost 200 times its weight already.
Feb 16, 2016, 07:17 PM
Registered User
Apphoard's Avatar
Quote:
Originally Posted by nerdnic
Hi there,

Here is what i'm running on the 80+ build:

MOTOR - NTM 35-48 1100kv (173g 1000w)
PROP - 10x10 APC
ESC - Dynam 80a
BATTERY - 3000 40c 4S
SERVOS - 4x 12g metal gear

With the alum spar the wing holds up really nice at any speed. I've built bigger, heavier, faster planes using the same alum spar and have never had a failure, even when trying.

The flat alum I use is 1/2" high 1/16" wide and comes in 3ft length. If you have a home depo or lowes around you, they should carry it for a few bucks. CF will work but you have to make a dihedral center piece. A bent nail or some other coupling should work.

I am quite new to planes, I don't understand how a 1100kv will push the plane so fast. It is because your using a 10" prop right? I know they make big and small 1100kv motors correct? How do I tell which 1100kv motor will turn a 10" prop correctly? Thanks for the help!
Feb 16, 2016, 08:39 PM
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nerdnic's Avatar
Quote:
Originally Posted by Apphoard
I am quite new to planes, I don't understand how a 1100kv will push the plane so fast. It is because your using a 10" prop right? I know they make big and small 1100kv motors correct? How do I tell which 1100kv motor will turn a 10" prop correctly? Thanks for the help!
I will do my best to break this down and maybe someone smarter than me can chime in also.

The speed at which your plane is going to fly comes down to how much air your prop is moving through, minus the plane it's dragging along. The way we measure how much air your prop can move through is measured by its pitch. And pitch is the distance in inches a propeller would move in one revolution if it were moving through a soft solid, like a screw through wood.

Okay so now that we have a baseline of what pitch is we can start to put together the info about the motor, battery, etc. The Kv rating of a motor is going to tell you the RPM per volt that it will try to achieve. The voltage here is based on your batter, so a 4s would be calculated at 14.8v. With this you have an idea of how fast the motor, and thus the prop is going to try to spin. With the pitch of the prop you also know how many inches the prop will try to cover per revolution.

The quick and dirty airspeed equation works out to something like this:

Pitch x Kv x Voltage / 1056 = MPH

Using the info from the motor I suggested the calculation looks like this:

10 x 1100 x 14.8 / 1056 = 154MPH

Now, you'll notice this seems pretty high, right? Well this is where it gets tricky. As you mentioned, you might have a 1100Kv motor sitting in a plane of your own. And you sure as heck know it doesn't go over 100MPH, so what gives?

Even though the motor says it's 1100Kv that doesn't mean that's what RPM its going to spin at while under load. Most likely it will spin at a much lower rate than what's advertised. This is where your 50g, 175w, 1100Kv motor will differ from a 180g, 1000w, 1100kv motor. The reality is, the 1000w motor is going to come closer to spinning at 1100Kv than the 172w motor. The more watts your motor can handle the more power will be behind the prop to actually spin it at the rated speed.

The equation doesn't account for this or your planes weight, design, drag, battery voltage sag, weather, etc etc, no single calculation is going to tell you what your real airspeed will be for any random aircraft. Best thing you can do is keep learning about how motors work while looking into recommendations from others. Once you start to wrap all the details up in your head it will make more sense about what motors might be good, until then, just ask!

I hope this helped answer some parts of your question :-)

---
It is because your using a 10" prop right?
The prop diameter does help with generating thrust but the pitch is the key to understanding air speed.

I know they make big and small 1100kv motors correct?
This is correct! They come in all sizes.

How do I tell which 1100kv motor will turn a 10" prop correctly?
This is by no means hard truth, but here are some guidelines I've used.

If a 1100Kv motor is rated at 350+ watts it can throw a 10x10 prop on 3s. 550+ watts is needed for 4s. If you have a smaller motor and you try to run a 10x10 on it you're going to make the motor work to hard and it will probably burn up. If you're running a 10x6 or so then you can get away with lower watt motors but you won't go as fast :-)
Feb 16, 2016, 10:50 PM
Registered User
Lawn Dart Flyer's Avatar
What Nic said... Now as far as building that Chipmunk, Are you sure you want to fly 80 mph as a new flyer?


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