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Feb 07, 2017, 09:57 AM
Build, fly, crash, repeat.
Lost In OC's Avatar
Thread OP
That looks tedious and very frustrating, precisely what I'm trying to avoid. I absolutely appreciate all of the information I've gathered from you while mining through other threads. You've saved me time by providing info.

I take no offense to your critique, all input is welcomed.

If it landed, it must have flown......how'd it go? What are the power specs? I'm familiar with the BOT so I'm curious how she flew on the amount of power you had available. This stuff just fascinates the heck outta me.
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Feb 07, 2017, 12:35 PM
Registered User
As I wrote, flown powered from pack, solar is for charging only in any design I know.
The thin 0.2 mm layer added by cells and less than 100g weight, not changed perceivable flight allure, flew as in any other day.
A lot of gliding was required, to land with pack full charged... about 1:10 on/off the motor ratio... add the very heavy ARF BoT, about 2200 grams... You will be better with lighter platform and plenty of power.
Monitored pack and cells voltage using Frsky telemetry. No current sensor, not needed.
Charge current was about 0,9A if I remember well, measured at ground. The 2x3" cells was been bought spec'ed as 1.3 A output In a hot desert at noon maybe...
No MPPT, the cells count (28) was intentionally chosen to output 14-15V, good to charge 3s using a stepdown with current limit.
Feb 07, 2017, 05:25 PM
Build, fly, crash, repeat.
Lost In OC's Avatar
Thread OP
@renatoa, plan to build another?


Finished the new bow cutter, it has a 48" width capacity. I'm not entirely sure why I made it pivot on both sides, damn symmetrical brain! If it becomes a problem, I'll just epoxy one side in place. It works pretty nice thus far, at least on 8" square hunks of foam. I'm either going to have to clone myself or train my wife how to help get smooth cuts and nice leading/trailing edges.

Here's a picture of the original 1/4 scale model of the solar plane I intended to build 2 years ago. Its without the pod and has a few holes in the wing but it did glide nicely. Never got around to finishing it, my 2nd kiddo was born about that time, funny how that works. Hmmmm, wonder if it would fly on 4 solar cells, ha!
Last edited by Lost In OC; Feb 07, 2017 at 07:00 PM.
Feb 08, 2017, 01:46 AM
B for Bruce
BMatthews's Avatar
Put a bit of nose weight on it and a hook on the belly and go looking for a free flight contest with a two line glider event....

Your test model looks remarkably like an A-1 category glider.
Feb 08, 2017, 02:20 PM
Build, fly, crash, repeat.
Lost In OC's Avatar
Thread OP
you're right, it sure does. I never knew that freeflight category existed. The similarities make sense; light weight, low power, max efficiency, and max endurance. It quacks like a duck.

Root airfoil templates...
Last edited by Lost In OC; Feb 08, 2017 at 06:01 PM.
Feb 12, 2017, 09:47 PM
Build, fly, crash, repeat.
Lost In OC's Avatar
Thread OP
The new hot wire bow cutter works great! Might need to put a little more tension on the wire.

I also built a couple of 90 jigs out of pine and oak to be able to cut dead straight blanks.

Now I need to go buy more foam, the 2x8 panel alone won't cut it, budum bum

Hot wire cuttin' (0 min 54 sec)
Last edited by Lost In OC; Feb 12, 2017 at 10:02 PM.
Feb 15, 2017, 10:38 PM
Build, fly, crash, repeat.
Lost In OC's Avatar
Thread OP
The custom Genasun MPPT is here! After being uncased and shedding the crimp connectors, it weighs in at a mere 24g, a bit lighter than quoted.
Feb 16, 2017, 12:54 AM
Registered User
Strange, no coils...
Not visible, at least...
Feb 16, 2017, 09:37 AM
Build, fly, crash, repeat.
Lost In OC's Avatar
Thread OP
Quote:
Originally Posted by renatoa
Strange, no coils...
Not visible, at least...
There's a 22uH inductor coil there, its just encased.
Feb 16, 2017, 09:44 AM
Registered User
Ah, the square outline made me think is the switching FET.
Feb 25, 2017, 02:10 PM
Registered User
Finally... someone did it !

THIS is the closest incarnation of my vision about how should be done a custom plane dedicated to solar propulsion !
Last edited by renatoa; Feb 25, 2017 at 02:17 PM.
Feb 28, 2017, 10:54 AM
Build, fly, crash, repeat.
Lost In OC's Avatar
Thread OP
Nice to see it finally successfully fly. I've been watching his progress for the last year. It will be interesting to see how it performs this summer.

Thats a lot of cells by the way!

A little update on my project...
- 13:1 gearbox arrived from Germany this week
- The fuselage from Croatia should be here any day
- I failed making useable foam cores. I think the wire tension is a little low and I need to switch to a 2 part rib template with a flat lead in and lead out
- Built a nice 6x4' tortion box table to assemble this thing
- Just bought a RES 23x12 prop and 3 twist spinner for a 23x15.01 folding prop set up
- Need to buy some carbon and get more 0.75oz glass

And a picture of the shop
Feb 28, 2017, 01:11 PM
B for Bruce
BMatthews's Avatar
It's way too clean... but that won't last for long....

I'm not a big solar power fan but you got me hooked when I looked up the specs on the solar cells. All the best with your build and I'm looking forward to watching the progress.

About the foam, the lead in and out pieces will help a lot. Even if it is only to add wires to the existing templates. And slow and steady wins the race. When I dabbled with cores briefly many years ago I found working with virgin foam helps a LOT. The trouble is finding virgin foam. You really need to go directly to a bigger distributor or if you're lucky like I was direct to the place that blows the foam from the pellets. I had to buy a whole 4x4x12' block but they cut it into 3" slabs at no extra cost and I split the order with a couple of buddies that made control line combat models. So they were happy to take a big part of the order.

The lumberyard insulation foam has lots of recycled bits and that snags the wire. Using the expanded polystyrene is better but is also double the weight. At any rate I found that less power and just a light steady weight let the wire cut with less distortion. It also aided with maintaining the tension better.
Mar 06, 2017, 08:30 PM
Build, fly, crash, repeat.
Lost In OC's Avatar
Thread OP
Exciting day to come home from work! The mailman left some goodies....

Straight from Germany, the RF 23x12 carbon folder/spinner and the CLM fuse from Croatia. Both absolute things of beauty.

The pups approve!
Last edited by Lost In OC; Mar 06, 2017 at 09:23 PM.
Mar 07, 2017, 03:07 PM
B for Bruce
BMatthews's Avatar
Mmmmm..... mini pylon..... YUM!

OK, now you've gone too far. Matching your dog's to the model component color scheme is just WAY over the top . I suppose when you get the wings done in red for the lower side you'll get a red Irish Setter too ! ? ! ? !

The prop and spinner hub threw me for a loop. Most of the staggered setups I've seen previously had the leading edges of the blades leading the cross axis instead of lagging the axis. But then seeing how the blades curve over and down to the mount point it all makes sense. A nice design option.


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