Foam Board Jenny

[Daniel Kezar]

I just designed it around whatever I had at the time. It used a 3007, 1100Kv Hobbyking Donkey motor turning a 9x4.7 Slowfly prop. A 3s battery was a bit too powerful but it flew nice on a 2450ma 2s running a 30Amp ESC. Servos were 5 gram but 9 gram might be a better idea. To sum up:

Motor: 1100KV Brushless Motor
ESC: 30A Brushless
Prop: 9x4.7 Slow Fly
Battery: ~2500ma 25-30c 2s
Servos: (4) 5 or 9Gram servos

I stole all the electronics from this plane for another project I'm working on, but someday I'd like to build an improved Jenny 2.0 so I can add a step-by-step build log for it.

ok. do you think it would downscale well for a 2213 935kv with 20 amp esc and 9x4.5 prop running 1000 3s? 9g servo of course

 

[Tench745]

The setup as is gives theoretical values of:
Thrust: 11.2oz
Stall Speed: 14.5 MPH
Max Speed: 26.7 MPH
Amp draw: 6.2A

Your setup would give you:
Thrust: 21oz
Stall Speed: 14.5 MPH
Max Speed: 36.3 MPH
Amp draw: 8.25A

I think this would work, but can't promise anything without trying it. You will most likely need to add some nose weight to get the balance correct.
If you do attempt to build this, I'm happy to answer questions and may end up building along. No promises though, I'm out of storage space.

 

[Daniel Kezar]

The setup as is gives theoretical values of:
Thrust: 11.2oz
Stall Speed: 14.5 MPH
Max Speed: 26.7 MPH
Amp draw: 6.2A

Your setup would give you:
Thrust: 21oz
Stall Speed: 14.5 MPH
Max Speed: 36.3 MPH
Amp draw: 8.25A

I think this would work, but can't promise anything without trying it. You will most likely need to add some nose weight to get the balance correct.
If you do attempt to build this, I'm happy to answer questions and may end up building along. No promises though, I'm out of storage space.

haha! thanks for the info! you should submit this plane for the card game (if you haven't already). you have all the specs!

 

[Tench745]

So, seeing as there was interest and I have a lot of free time lately, I updated the plans to address problems I had with the last model and make assembly a little more self-explanatory.
View attachment McB Jenny.pdf

 

[Daniel Kezar]

So, seeing as there was interest and I have a lot of free time lately, I updated the plans to address problems I had with the last model and make assembly a little more self-explanatory.
View attachment 102736

thanks! downloaded now!

 

[Tench745]

Zombie Thread!
I was going through my files and decided to tidy up my last version of the plans for Jenny, they are now included in the resources section (visable as soon as it gets approval).
https://forum.flitetest.com/index.php?resources/mcb-jn-4-jenny.270/

In putting that resource together, I also realized that I never posted the last video I made of my Jenny flying.

 

[Mr NCT]

Starting my second JN-4 (does that make it a JN-5?) based on Tench745's plans. Going with folded wings top and bottom and printed firewall, radiator and cowl/battery hatch. Made the pin on the hatch that fits in the hole on the firewall with a hole to reinforce it with a chunk of BBQ skewer for strength. Really enjoying having a 3D printer.

 

[Tench745]

In light of Flite Test releasing their Jenny XL kits, I'm going back through my plans for the Jenny, building a new version, and polishing up the plans as I find errors during construction. I've already removed a couple redundant marks on the plans and fixed an error with the wing struts/aileron area.
The biggest change for this coming version will be a foamboard turtledeck.

 

[Tench745]

Yesterday was the maiden flight of the prototype. CG was too far aft, but it flew well otherwise.
After a couple tweaks to improve the CG and thrust-angle, she flew again today. It flies like a Jenny.
Updated plans and a build guide are in the works.