After pottering around for a couple of evenings, I finally got the tail linkages sorted out.

I went ahead and worked in some 4-40 bolts into the elevators that I installed into small hardwood cylinders. I then epoxied these into the elevators flush with the top and re-covered. I found it helpful to drill the cylinders for the bolt diameter and then open up the hole to the depth of the bolt head to recess the head into the block. The rudder was done in a similar fashion by threading a 1-1/4" bolt through the block in the rudder and then cutting off the bolt head once it was even on both sides. These control horns, although a tad heavier, are very effective and make for a clean surface.

I made my forked elevator pushrod from the standard arrow shaft and 2-56 threaded rods. Unfortunately, the 9" shaft lengthened to 17-1/2" by the 2 rods on the elevator end and the single rod at the servo end came in weighing 20g or 0.7 oz. This is rather heavy (the equivalent of 2 servos) for a model of this size and I'd like to find a 10g alternative to also remove weight from the tail which is now needed. The rudder was setup with light P-P wires, 2-56 rigging couplers and nylon clevises at both ends. I also ended up using nylon clevises on the elevators as ball links were not needed. The linearity of the pushrod is good and it is sufficient to put a ball link at the servo end to prevent adverse torque on the servo. Both the elevator and rudder linkages exit the fuse from the same opening covered by pushrod exit guides (painted to match the white MK).

I received the new 25C lipo's which come with nice 3.5mm EC3 bullet connectors. Unfortunately, my other electric stuff is all rigged with Deans so I'll have to change them. This wouldn't normally be an issue however, it appears that my three soldering devices have all packed it in! Time to pick up something robust that can also weld soldering clevises and threaded couplers. The aileron linkages are basically done except for two soldering clevises which need to be attached to the control rods. These will be used at the torque rod end with ball links on the servos.

Few things left to do! Some soldering work, glue in the hinges and a little tidy up work on the canopy. I obtained some magnets and will probably use one for the canopy as the screw tends to lift up the paint. I'll also need add some clear to the paint to protect it. Final cosmetics can probably wait until after the maiden.

I'll take some pictures of the radio compartment and interior next time.

David.

With the heavy elevator pushrod and the new 7 oz 25C lipos the finished AUW of the model is 30 oz. With the 15C TP Prolites I can drop this by 1.5 oz to 28.5 oz. The wing loadings are in the range of 16 and 15 oz/sq ft, respectively. This is perhaps an ounce or two heavier than I had hoped for but still well within my goal of under 2 lbs max.

I will probably use the heavier 25C cells as the model balances nicely with the rear of the battery flush with the FW - that is, all the way forward. I suppose this was to be expected considering the heavy linkages and fully airfoiled tail surfaces and solid stab.

It would be nice to find a forked 10g elevator pushrod alternative to my heavy FG/steel assembly.

David.

TRY CF PUSHRODS THAT COULD HELP A LOT .
YOUR LIPO'S ARE 2500 mah I GUESS, DO YOU HAVE ANY LIPO'S AROUND 1200 tO 1500 mah ?

Rafa,

I'm sure the CF pushrods would cut the weight down to 10g or less, the only issue is that building a forked CF rod is tricky; at least no easy way comes to mind. I suppose I could set things up with the more common DEPS approach. I'll have to loook into that.

The lipo's are indeed 25C 2350's and yes, I do have some 1350's which shave off 3 oz from the 2350's. That would make for a 27 oz flying model assuming I can get the model to balance with them after replacing the heavier pushrod - most of that weight, 0.6 oz, is in the rear of the model where the steel rods exit the fuse. 1350 size packs would make for pretty short flights though I expect.

I'll have to look into all options.

David.

Yeap flying time would be around 7 to 8 minutes maximum.

Even using a main CF push rod and rest of fork made convencional you could save some weight, sure you'll come up with some ideas.

Rafa,

Not crazy about the 1350 packs on 300W (28A) but we'll see.

The main section is 9". Switching to CF wouldn't help that much as the FG is not much heavier. It's the steel rods that need to be replaced. Question is, how to get them to rotate out of the fuse and join into a single rod for connection to the servo.

Any ideas? I'm starting to have a few.

David.

Back of the envelope gives me:

[ul][*] 1350 mAh packs: 2.83 min @ WOT ~ 5.66 min for average flight (@ 1/2 WOT)[*] 2350 mAh packs: 4.93 min @ WOT ~ 9.86 min for average flight (@ 1/2 WOT)
[/ul]

However, I need the nose weight so I might as well put it into electrons.

David.

Brian Courtice will be building public Pico #3! Cores and possibly a short kit is being arranged for him probably by Don of Eureka Aircraft (or myself if necessary).

Congratulations on choosing a fine aircraft and concept . The only requirement when building a Pico is to do a build thread, preferably in the CP forum!

Happy building!

David.

David where is the maiden report ? Im sure the PICO havent fly yet, seems like you'r taking to much time for it.

Hope to see the pics or video of maiden flight soon.

I haven't heard much about this topic in a while. Any news?

Tom and Rafa,

thanks for your inquiries on the latest with the Pico.

In the interest of full disclosure, a first maiden attempt was made under improper circumstances about a month ago while on holiday - an inexperienced launcher (my dad - a train modeler...), a quickly setting sun, a multitude of nasty biting insects (black flies, horse flies, mosquitoes, etc.) and to my dismay a laterally unbalanced model (that won't happen again).

While in the hastiness and excitement all appeared ready to go, upon the poor launch the model went full throttle from a 7 ft height to terra firma in the matter of 3 seconds. I barely had a chance to pull on the stick before it went in at about 20 degrees so that the left wing tip and nose hit at the same time. So that is the bad news...

The good news is that the model was barely damaged. The wing, as expected, is intact. The nose section had a little damage which will essentially entail some glue but not much else. The one thing that will need repair is the rear wing ply mount which was actually split by the wing forcing it upon impact. Neither the wing bolt dowel nor the fuse sides suffered any damage - whew!

In short, I need to find a day to do these minor touch ups, balance her laterally (a little weight on the right wing tip) and get her on the wing again. The further bad news is that I haven't even seen my shop in the last 45 days - as a self employed person, I've never had a month as busy as September. But today is October 1st and I'm longing for a little balsa dust and a better second maiden to look forward to.

David.

P.S. The three of us - dad, myself and son - all came away from that maiden attempt with a collection of very nasty bites. The black flies are the worst. In retrospect, it was a good thing I didn't have 7 minutes of lipo time to enjoy on the first maiden. There's nothing quite like the feeding frenzy of insects at dusk... they might as well have been eating each other!

David it's good to know about your first attempt, well sometimes sh.... happens huh?
Hope you get it to fly soon!

I grew up in Ontario, Canada, and I know all about black flies. Not fun.
I'm glad the Pico didn't get hurt too badly. Fix it and fly it again! I am really lookng forward to a real flight report.

hey david i started my own picorare. Got two 350 watt motors coming so i figures why not. Got the stab cores cut and that was a steep learning curve. Burned up alot of foam getting them right but now that i know what i'm doing got them cut and started to sheet them. Just thought you might like to know. Phil

Hey Phil,

cool news! Make sure you post your progress - always interested in seeing alternate approaches to one's own.

Did you get the wings cut?

David.

nope no wings yet burned up alot of foam learning how to cut and get my speed down but finnally got it and while not perfect they will work. Anyways i have a few pics of the stab so far. It is sheeted assembled and all that is left is to joined. Have fuse sides cut and plan on maybe cutting the wings this weekend. I have to maiden the vortex but if that goes well i hope to get the wing cut this weekend. I plan on doing retracts in this one to. Any suggestions for the nose gear. I will be using the same mains i used in the vortex the gp .10's any ways rambled on long enough. Here are the pic's more later. Phil

Good stuff Phil.

On my Pico I sheeted both the wing and stab with 1/32" contest balsa. I was very pleased with the overall weight of the wing but the fully airfoiled stab resulted in a tail heavy model with the light electric motor up front. Balance was obtainable by putting a 2650 mAh 3s lipo against the FW but it also brought the model up to 30 oz AUW (if memory serves). A couple of things you could do to help - core out the stab on the underside (ideally before sheeting but it's also ok if there are holes in it especially if you used 1/16" sheeting) in four holes or so per side in the aft 1/3 of the surface, bore out the elevators (again, probably four holes per side) and make sure you use light plastic dual elevator pushrods and join them at the servo somehow. P-P on the rudder.

I built up the rudder per plans using 1/16" sheeting to cover it but you could probably achieve the same weight by cutting a solid balsa sheet and boring out generously. Make sure you put a hard edge on the TE to prevent it warping. You might also want a cross grain piece along the bottom to sand it nice and round and give the rudder additional strength. Use a piece of 1/16" ply on the fin post base and balsa atop - you'll need it, otherwise it will break in time.

Note that I also bored out my fuse sides to a swiss cheese look. I would do this again except for the hole in the fuel tank area - strength there is important. I think I used 3/8" tristock along the fuse top where I capped it with 1/4" balsa sheet. The front canopy was layered up and then carved out - it turned out quite light.

Things are quite tight in this model especially if you use retracts. The mains should be fine and you can do them per the Vortex/Deception (D10). However, I recommend that you do some careful measurements to figure out how long a nose gear strut you can use since this will dictate where the main wheel wells, and ultimately the main retract units, will go. One way to deal with this would be to build the fuse before the wing. On the D10 I used a Robart 1/2A nose gear and it is fine but you'll need a second servo for it (three servos in the fuse). If you go this route, you will have difficulty getting the radio gear in the fuse if you have aileron servos in the center wing. Put the retract servo there buried deep and use 9g servos for the ailerons outboard.

Given all this gear, the model will likely tip the scales at closer to 36 oz. I estimated that anything above 36 oz AUW would be excessive. If you hit 40 oz I think you will have a bullet on your hands and longevity might be minimal... If I were to go this route again (I consider having done it on the D10), I would probably modify the wing root chord and enlarge it by 1-2". Probably 1.5" and bring the area in the 320 squares ballpark (I believe it has 275 per scaling).

I used an 8x6 prop on mine but haven't measured how many electrons it is pushing. I'm estimating close to 300W. If done again I'd go for a high kV motor than what I used (1450) and turn a 7" prop instead.

Oh, and use light film covering such as Ekonokote, Towerkote or Solarfilm.

David.

I'm not clear on the mechanism of this nose gear but they may also be an option:

http://www.hobbyking.com/hobbyking/s...dProduct=12953

Given the dual MG servos you'll probably want to use on mechanicals, these may also be an option:

http://www.horizonhobby.com/Products...odID=EFLGP0150

There is apparently a nose gear that goes with them.

Someone from Horizon is interested in building a Pico with these units...

David.

hi david. I will keep you posted on progress. Everything that you suggested is what i was thinkin anyways. So i'm gonna proceed with taht. Thanks for the lead's on the retracts thee-filtes look a little pricey and the hobby king ones i don't know about but for 12 bucks i just might have to try them. I actually made the plane a little bigger overall and scaled the .60 down to 67% so that is the size i'm building at. Everything measures out to conventiaal dimensions 13/4 whels 1 1/2 spinner etc. So i think that may help the wing loading just a shade. We'll see but with the way the vortex turned out i'm pretty sure i can this one light enough too. Anyways more tommorrow just got the stab halves joined and waitin for them to dry. Phil

Cool, 43.5" span - same as the Vortex if one includes tips I believe. The Pico is 40" tips included (61.5% scale).

I would have suggested to go with 48" span if you weren't already invested. But then that would have required ~600W. The nice thing about the Nano is that the retracts are much easier to deal with. E-Flite (or knock offs) trike electrics, Robart's (pneumatic or mechanical), Spring Air 600's, and, of course, MK SS mechanicals. Here are Robart's options:

http://www.robart.com/store/retracts...-weight/2-5lbs

And some electric variations:

http://www.hobbyking.com/hobbyking/s...t_System_.html

http://www.hobbyking.com/hobbyking/s..._version_.html

http://www.hobbyking.com/hobbyking/s...ht_1pair_.html

Actually for the Pico+ (67%), these might be the ideal set. Even the correct wheels are included (1.7"):

http://www.hobbyking.com/hobbyking/s..._Version_.html

They are not as low cost as mechanicals but keep in mind that MG servos are not cheap either. The mechanical setup might be slightly less expensive but probably about the same weight. I know that for 25-32 size models (~78% scale), the mechanical setup is heavier than electrics. E-Flites weigh 5 oz AUW. Mechanicals are more than that with two servos. I read a review from someone who build a model with those units and he was very pleased. They have a nice small body footprint.

Something to think about. I'd still build the fuse first to make things easier, or, build the wing but don't join it and leave the wells until after the fuse and nose gear is setup.

Oh, I'd also recommend that you stay away from 1.5" spinners unless you go with something like a TT or GP aluminum electric spinner (pricey). I'd use a GP plastic 1.75" spinner with alum backplate on these models. I tried to use a 1.5" on the D15 as it was what scaled and I ended up having to refit the front end for a 1.75" as the smaller one was just too small for an 8x6 / 9x4 prop.

David.

oh oops meant to say 1 3/4 typo. After looking thinkin i'm just gonna go with the e-flite 10-15 size electric trike set. For the price will save alot of headaches. Well hope to get the wings cut this weekend and we'll go from there. Phil

You'll love them, Phil. I have built the EFL 10-15's into several planes this size.

Andy

I'll take Andy's word for it but 5 oz AUW for the retract system sounds like too much to me for a 36 oz model. Even a 42 oz model. To me, they are really 20 to 32 size retracts but now I see that E-Flite has some 10-15 size retracts. I don't know if they are any different from the 5 oz trike units I have in mind but perhaps they dropped the strut diameter to 2.5 mm instead of 3 mm which would lighten them some. Unless you have a span of 45" minimum, I'd consider these units too large and heavy but that's just me.

I sure don't want to interfere with any Horizon sales...

David.

You must build heavy, David.



Andy

hey david phil here. I haven't forgot about building this i decided to go in a differnt direction and make a foam plug and lay up a fiberglass fuse for the pico. Ifigure a good time to learn and if it fails i can always go back and make the wood fuse. Starting on the plug this weekend. Will keep you updated. Phil