nnChipmunk v2

nerdnic

nerdnic.com
Mentor
At first, no. I maidened it with a normal motor and it crashed when I let my brother fly it and turned away to watch another plane. :p That was when the wingtips broke. I repaired it with tape and flew again with the tacon motor. That worked until I lost it in the sun. I repaired it and a few days later flew it with the tacon again. It worked really well for a while, but then mid-flight the wing snapped and I barely saved it from a death spiral. The power pod tore through the plane and it is currently unflyable. And that's the story of my Chipmunk v2. :)


P.S. I also sent you a message asking about the A10 v2.

That is quite the story! Are you gonna rebuild with the speedwing this time? For the A-10 I got your message and will send over the plans for you to test once I clean them up a little.
 

nerdnic

nerdnic.com
Mentor
I built a mini chipmunk style plane with a sort of nn style speed wing. It was only meant to be half a wing to practise the technique but I ended up with a full plane. I have a thread for it here but I think the title is a bit misleading http://forum.flitetest.com/showthread.php?30432-Mini-speed-wing-racer

After seeing the performance and durability of this aluminium reinforced speed wings I'll definitely be building a fast chipmunk next

Very nice! You did a great job on the wing. Please keep me posted on your chip build!
 

shiitake

Member
Nooooo!! How bad is it?

The drone ripped the tail of. That is the main thing I think (also prop and landing gear need attention). I was low, that made a huge difference. Strangely enough I have no pics of the aftermath (I really was pissed I guess!).

2016-10-17 12.15.37 (768x1024).jpg
there is no thing as hotglue can't fix.

ARF:
2016-10-17 12.18.43 (1024x768).jpg
 

Jordan3367

Member
That is quite the story! Are you gonna rebuild with the speedwing this time? For the A-10 I got your message and will send over the plans for you to test once I clean them up a little.

Thanks! My friend built a chipmunk with a speedwing so I'm going to trade him for that and try it with the tacon. More story time: :p His chipmunk seemed to have weird issue with stalling at a lower speed. It was difficult for him to control and he crashed it out in the field. Fortunately, there was no damage but he doesn't plan to try again. I'm not sure why it didn't work, possibly a combination of a different airplane & wind? Anyway, I plan to try his plane with the tacon motor and we'll see how that goes.
 

nerdnic

nerdnic.com
Mentor
Thanks! My friend built a chipmunk with a speedwing so I'm going to trade him for that and try it with the tacon. More story time: :p His chipmunk seemed to have weird issue with stalling at a lower speed. It was difficult for him to control and he crashed it out in the field. Fortunately, there was no damage but he doesn't plan to try again. I'm not sure why it didn't work, possibly a combination of a different airplane & wind? Anyway, I plan to try his plane with the tacon motor and we'll see how that goes.

It definitely doesn't have a very bad tip stall or stall in general, so that sounds like maybe he was tail heavy or a wonky build?
 

Jordan3367

Member
Update-

I flew my friend's chipmunk, (the one with the speedwing,) and it flies really well! Sooooooo fast. :)
It's still in one piece, too. On another note, A-10 plans? It has been 2 weeks...
 

jpot1

Elite member
I printed this out today to try to get back to the fold over elevator and rudder. I had trouble with these previously and had put the build down. I cut the elevator out twice and was not happy either time. First time I'm not sure if I did something wrong with the bevels but when I did the foldover the paper split in several spots. So I cut a second one with wider bevels - the green lines are roughly 3mm so I went 5mm. Foldover went much smoother but then trying to close up the trailing edge did not come out cleanly.

So do you think it's possible to build this plane with a single thickness elevator and rudder? I'm not looking for speed, just a fun park flyer. Alternatively I could go back to the v1 plans and adapt those with a front hatch and tapered spar. Thoughts?
 

nerdnic

nerdnic.com
Mentor
I printed this out today to try to get back to the fold over elevator and rudder. I had trouble with these previously and had put the build down. I cut the elevator out twice and was not happy either time. First time I'm not sure if I did something wrong with the bevels but when I did the foldover the paper split in several spots. So I cut a second one with wider bevels - the green lines are roughly 3mm so I went 5mm. Foldover went much smoother but then trying to close up the trailing edge did not come out cleanly.

So do you think it's possible to build this plane with a single thickness elevator and rudder? I'm not looking for speed, just a fun park flyer. Alternatively I could go back to the v1 plans and adapt those with a front hatch and tapered spar. Thoughts?

Sorry to hear you're having trouble. It's definitely a different technique that takes time to master. I was just taking with James about this on my 800 spit wing.

You can definitely do single layer. Just adjust the v and hstab slots, as well as the formers the v stab ridge sits in.
 

jpot1

Elite member
Thanks for the quick response. The adjustments look simple enough. I will give this a shot and post pics of the result. I have built the nnSpitfire as well at the 800mm size. Thinking of going bigger so I can swap one size power pod. Would the same apply to your larger spit with single layer stabs?
 

nerdnic

nerdnic.com
Mentor
Yep! One other thing I didn't mention. The tail belly plate allows for the two layers thickness, so it will but a little wide. You can just add a little shimming on each side of the vstab.
 

jpot1

Elite member
Is there a recommended grit sand paper for those that sand the bevels? I may try that technique vs. using a knife.
 

nerdnic

nerdnic.com
Mentor
You can use a heavy grit to rip through the foam fast. It doesn't have to be clean and nice, so use what's fastest for you.
 

Verris

Active member
Just laid out the plans to cut on my needle cutter tomorrow. It would be nice to include the number of each part required on the plans, and if it should be reversed or not. I'm assuming 2x of both spars, 2x reversed wings and 2x reversed vstab. Normally I would have only cut one vstab, but I happened to watch part of the build video first!

Also a note for anyone thinking about buying the advanced motor, its currently on sale for $8.61
https://hobbyking.com/en_us/ntm-prop-drive-series-35-48a-1100kv-640w.html

Unfortunately, no accessory kits in stock at the global warehouse.
 
Yesterday, I maidened the nnChipmunk V2 which I built from a kit. For power, I went with a Turnigy D3548 1100kv motor, a Plush 60A ESC, and a 2200mah 3s battery. With that heavy motor on the nose it balanced pretty close to the spar without a battery. Makes it nice for trying different batteries. For the first flight I tried a 10x3.8 slow fly prop. I didn't want a high pitched prop to start with, just wanted to get it flying and trimmed out. It was a bit gusty so only got in a couple flights. Flew pretty nice once I got it dialed in. I have an FT Mustang and FT Spitfire so had a pretty good idea what to expect. Later in the day the wind died down a bit and so I threw on a 10x7 prop and got in a couple more flights. The higher speed was real nice but no where near its potential! My plan is to increase prop pitch a couple more steps to 10x10 which Nerdnic uses on his 100mph+ set up. I currently only have 3s batteries and so I plan to get some 4s batteries to push it past 100mph. I will probably need to replace the 60A ESC with an 80A ESC as Nic suggests. I will also reduce prop pitch to start with until I'm comfortable flying it at faster speeds.

I'm really pleased with the quality of the nnChipmunk speed build kit. I had a couple questions which Nic responded to immediately. I'm looking forward to future kits that include the speed wing.

Ray
 

nerdnic

nerdnic.com
Mentor
Just laid out the plans to cut on my needle cutter tomorrow. It would be nice to include the number of each part required on the plans, and if it should be reversed or not. I'm assuming 2x of both spars, 2x reversed wings and 2x reversed vstab. Normally I would have only cut one vstab, but I happened to watch part of the build video first!

Also a note for anyone thinking about buying the advanced motor, its currently on sale for $8.61
https://hobbyking.com/en_us/ntm-prop-drive-series-35-48a-1100kv-640w.html

Unfortunately, no accessory kits in stock at the global warehouse.

This is good feedback. I think I included the count on the build notes but not on the plans themselves. You are correct in your count though!

How did it cut for you?
 
Got a good dozen or more flights in now with the 2200 3s and 10x7 prop. Discovered I had the CG a little forward of the CG indicator which was ok for initial flights. Moved it aft to the CG indicator and I could tell the difference. It zips right along with this setup! Getting pretty level flight at different speeds trimmed with a little up elevator. Nice plane! Impressive what you can do with foam board today.

Ray