doxilia

My Feedback: (3)

Well,

despite trying to not over extend myself build wise (along with their associated threads), here Iam starting a new one. Idecided Ineeded a light build fix to break up the labour of building full scale Tipo's. My idea was: "I'll just cut some fuse sides and after I'm done sheeting the cores, she'll come together in a few days..." Is that naive or what!?

But... so it was that the build of the Picorare (40" span Tiporare) begun. Ihave to admit that I sheeted the wings a week ago Monday so all in all, it's looking like this may be the fastest pattern build I've ever gotten my head around. Isuppose mulling over the plans for a year (or has it been decades?) does help.

Getting to the meat and potatoes. Ihad cut cores for the Pico some time ago and as mentioned elsewhere, Ipicked up some nice 1/32" sheeting last week and went ahead and skinned the wings and stabs. While things were setting up, I built myself a short kit for the fuse and fin and built up the rudder. So far, everything is being built per plans - at least as close to them as I'm able to. The wing panels and stab are finished with wing joining and mounting to be done. With the goal of making this Pico as simple as possible but no simpler, the model has no landing gear and will be electric powered (~300W). Some details on the power system and radio are mentioned in the Scaled Tipo Plans thread begun some time ago. More on that to come.

Tonight, I assembled the fuse and built up the sheeting sections around the nose and installed the fuse top. Once all was lined up and ready to be bonded, Ihit the joints with CA and proceeded to make serious clouds of dust! As I still don't have the motor (2 weeks ETA), Ifigured out how to build the fuse leaving the FWout. When the motor arrives, I'll backplate it on to the nose ring (1/32" shim) figure out what length standoffs Ineed and bolt the motor to the FW. WIth that lined up accoding to right and down thrust (built into the fuse), I'll then glue the FW in place at the angle it needs to reside.

In a matter of a few hours, she actually is starting to look like a Tipo!!

More sanding still to come...always.

Hope you pattern aficionados enjoy the thread!

David.

P.S. Isn't the shot through the nose ring cool!?

doxilia

My Feedback: (3)

Oh,

for the sake of good bookeeping, here are the current weights as things stand:

Wing panels = 5.5 oz

Fuse, stab, fin parts and spinner = 5.3 oz

Add some 1/16" fuse bottom sheeting, 1/16"ply radio and battery plate, some rails, a 1/8" wing hold down plate and some glass cloth on the wing and stab center sections and Iexpect the airframe should come in around 14 oz. Add some light film covering and the model should come in under 18 oz finished (less?)

The motor, esc, battery and radio is in the 10 oz ballpark. Add some linkages and we should be able to nail this one under 30 oz AUW... yes!

David.

doxilia

My Feedback: (3)

One more thing. In case anyone is wondering how I'll get the motor, esc &battery in there (Iwould), the complete front canopy section is removable. It is just tacked in place (I hope!) and will be mounted with two small dowels in the front and magnets in the rear. ARF style - but done a little better .

Actually, the entire canopy is practically hollow, it just can't be seen yet.

David.

alcarafa

E-power engines need a lot of cooling ( not to mention ESC and Batts ) so air must flow thru cowling & FW somehow, have you decided how air will flow inside ?

My new PICO wings are sheeted with 1/16 []cant find any 1/32 down here, they look great anyway !
Fuse will be 3/32 balsa and plywod FW rest of formers will be 1/8 balsa not very different from the first one I build, hope this one comes out lighter, because of E- power.

I have now been thinking on building the giant tipo and put a 23 cc gas engine on it, but before that I'll have to finish an overhaul on my AT-6, a YAK 54, WARLOCK, GULFSTREAM,STARLITE, ooppssss to many half done and sitting on bench for sometime now, see David your not the only one with unfinished birds !!!!

doxilia

My Feedback: (3)

Hey Rafa,

thanks for the feedback.

I had envisioned how to cool these puppies some time ago with the planning of the Nanorare (48" span 25 size Tipo). Although Iinverted the access to the interior making the canopy removable instead of making the fuse bottom into a hatch, the cooling will be the same.

You'll see two circles drawn on the FW in the first picture of the formers. The top one basically is a hole which is concentric with the motor. The motor cables will probably pass back through this hole. Below it is another smaller hole which will be inline with the bored out fuse chin. This will funnel air straight on to the ESC which Ihad envisioned putting on the fuse floor. Now, I'm thinking that it might be a better idea to locate it on the underside of the battery tray. Wouldn't want a landing to wreck the ESC through direct contact. Either way, air flows over the ESC and allows air into the motor bay.

For the battery itself, which will sit atop a tray located on the thrust line (probably sitting half way along F2), another hole will be bored out in the canopy front and directed downward straight on to the battery. Much like a TP exhaust diverter if you will. This is shown in the sketches Imade on the Nano plans some time ago and is the same idea that Mark had for his mini-CurarE (see Tipo plans thread).

For the motor, Imay build two small NACA inlets on either side of the motor bay if needed. I'd rather direct another tunnel from the canopy hole straight on to the motor from the top to keep the lines clean. Air will be exhausted out the bottom rear in front of the sub fin in order to avoid weakening the fuse behind the wing TE. The latter area is probably where the model will be held to launch it.

I'm glad you're working on your replacement Pico! Ihave to say that the fuse front was a workout. Perhaps I was a little tired but it took more work than Ienvisioned for such a small model. Some shaping still remains to be done. Isheeted my Deception 10 (D10)wings with 1/16". It came out a tad heavier but then alot of it is due to the fact it is a larger wing and it has a bellypan. I did use 16-18g sheets on the D10. I hope you found some light stock in that weight range - alot of it can be 23-27 g weight. With a good sanding you can bring it down to 1/32 and still keep it light.

While the D10 has 308 squares of area, the Pico (T10) only has around 270 (1.875 sq ft) if Irecall correctly (have to check the D10 thread). In order to keep the model at good wing loadings (especially for electric), she should be sub 32 oz (2 lbs). Ideally, she'd come in around 28 oz for a wing loading of under 15 oz/sq ft. Ibelieve that light 2100 packs come in around 150g (5.5 oz). One way to reduce the AUW would be do go with an 1600/1800 pack. FPhas some nice new (albeit pricey ~$45) EON-X lights 1600's at 123g (4.3 oz). However, if Ifind my 15C TP prolites (2100's) are too heavy or lack punch, Imay try out the low cost 25C Zippy/Rhino batts which cost 1/3-1/2 of that.

Happy building!

David.

turbo.gst

My Feedback: (8)

What a cool project. I am curious as to what size motor you will be using. I am trying to decide on e-power in the .10-.15 range just thinking out loud at this point.

turbo

doxilia

My Feedback: (3)

Hi Turbo,

Thanks for the enthusiasm!

Check out the end of the Scaled Tipo Plans thread:

http://www.rcuniverse.com/forum/m_78..._1/key_/tm.htm

There's some dicussion on motors for this project there. I'll bring this thread up to date on that front when the time comes. Here's a picture of what is on order for the Pico:a Dualsky 28-34-1460 (6 turn) which should swing an APC 8x6E at around 11Krpm peak and 300+W.

David.

doxilia

My Feedback: (3)

Well,

with the latest shots, she's really starting to look like a mini Tipo!

I'm quite pleased with how quickly this build has moved along - 10 days thus far. Not bad for a scratch build. While the Deception 10 moved at a good pace in the beginning, it was a much more time consuming build. Perhaps I wasn't as organized.

This evening I got the fin framed up, sheeted, blocked and rough sanded to shape. This, as expected, was a job of precision and care. The fin LEis not quite symmetric at the moment so a little more sanding on the LHSwill be required. Iwasn't quite sure how to tackle the frame up given the small pieces and difficulty in alignment. Iproceeded in one way, but next time I think I could use a better technique. Unlike a wing, it would probably be best to first install the fin post TE followed by root rib on to the fuse. Then the sheeting would be bonded to the bottom of the post and base of the fuse. The LE sheet support triangle would be installed next followed by the mid and top rib using the LE sheet for spacing. Finally, the LE sheet would be glued to the three ribs and triangle and the sheeting brought in flush to the ribs. The only trickery with this approach is that one would have to use aliphatic rather than CA.

I also got the rudder hinged and beveled, sheeted the fuse bottom rear (cross grain) and made the fin tip out of three pieces of 1/16"balsa - the first two at angle grain. A hardwood TE will be added to the fin tip in a similar fashion to the rudder TE and wing/stab tips. The only pieces of wood Ihave that remain for the build are the sub fin, the fin tip and the FW. I'll have to cut the radio and battery plates as well as the wing hold down plate.
But that will be it - no other wood required! Well, there will be the wing bottom wood pieces.

With the build practically complete, next I'll move on to joining the wing panels and mounting on to the fuse. I'll probably follow with the radio and battery plates prior to some further final sanding to the fuse before aligning and bonding the stab in place. Sub fin and fin tip will be last.

David.

doxilia

My Feedback: (3)

Despite some glue being used and having added sheeting to the fuse bottom, the fuse actually dropped in weight tonight! She went from the component 5.3 oz down to 5.2 oz. At this point, adding the 3 plates and the wing bottom pieces, I'm pretty confident that she'll end up sub 6 oz. The trick will be to make the wing fillets as light (small?) as possible. Epoxy and microballoons weighs.

With a 6 oz fuse + empennage and a 6 oz wing (glassed and bottom center added), it'll be a matter of seeing how much film covering will add to the 12 oz airframe weight. Again, in the spirit of keeping things low cost and simple, I decided to try out some Towerkote. From what Ican read into it, this stuff is identical to Ekonokote, if not simply a lower cost repackaging of it. All the colours Ineed are available.

All things considered, it's looking quite probable that I'll end up with a sub 30 oz flying model - again 28 would be ideal.

David.

doxilia

My Feedback: (3)

Here's a quick itemization of the gear I plan to use:

[*]Servo's: Futaba S3114's (4)[*]ESC: Castle TB36A / 3A BEC[*]Battery: Thunder Power 2100 3s Pro Lite[*]Motor: Dualsky XM2834CA - 6 (1460 KV)[/list]The rudder and elevator servos will be mounted inline as shown in the sketch with the Rx in front of them. A light P-P linkage will be used on the rudder while a forked glass arrow shaft pushrod will be used for the elevators.

The two aileron servos will be mounted in the wing center and will each opearate a torque rod. Using two servo's will allow independed control of the flaperons.

The battery and ESC will be mounted to a plate (one on each side) located on the thrust line while the radio tray will reside deeper in the fuse at the tuck line.

More on that coming soon.

David.

alcarafa

David If I where youI would avoid using towerkote, i used it in my first PICO and couple weeks after regret it, itwas a bad experience overall, get a roll of ultracote light you'll love it.

I think your PICO will be around 500 to 550 grm all included if not wrong, what do you think ?

turbo.gst

My Feedback: (8)

David,

Towerkote is econokote repackaged. I have used it with good results. Just don't reshrink with too much heat don't ask..... lesson learned.


turbo

AndyKunz

Do yourself an even bigger favor.  Use Solarfilm.  It sticks betters, STAYS shrunk better, and is lighter than either of the others.

Andy

AndyKunz

Use medium or thick CA, COLD. It won't cure nearly as quickly. Then spray kicker on the OUTSIDE of the wood. The fumes will penetrate and activate the glue. I used that technique back when I was selling kits for making sheet-over-rib wings.

Andy

doxilia

My Feedback: (3)

Guys,

many thanks for the recommendations and suggestions. I'll keep all of them in mind.

Although it doesn't look like much, Imanaged to get a fair amount done in the last couple of evenings (despite having the flu).

First, Ipaired down the fuse another fair amount. Now it has the correct shape - top and bottom. Tuck lines remain to be done but they will be last once everything else is done - particularly the installation of the motor as this will slightly alter the width at the nose. Before doing the tuck line, the fuse sides must be flush with the canopy.

I pulled the canopy loose and proceeded to figure out the internals - radio tray and battery/esc tray. These two things took an entire evening. It's when you get to these little details that working on models this size requires abundant patience! In any event, it's done. The radio tray consists of a small 1/16" ply plate holding the rudder servo in the back (P-P setup) and the elevator servo in front of it. Although I typically mount these in reverse order in order to avoid cross over of the P-Pcables on the elevator shaft, here it was necessary to invert the order to allow the elevator servo to be mounted on its side where the fuse is sufficiently wide (barely). As you can see, the operation of the elevator pushrod happens on the interior side of the servo to locate the pushrod on the C/L. The main Rx (Spektrum AR 6200) was going to reside just in front of the elevator servo but there isn't quite enough clearance between the connectors and the aileron pushrods emerging from the wing center section. A simple solution will be to invert the order of main and aux Rx's by locating the main on the fuse top (floor when inverted) and the auxiliary on the radio plate. This works out nicely.

I also got the wings joined, glassed (6 oz x 1" followed by 3/4 oz x 3") and the servo center box installed. The servo's sit with their control arms flush with the wing top and are mounted flush with the fuse sides (this all required measuring everything 5 times in different ways!) with their control arms toward the center. The outer portion of the arms lines up nicely with the torque rods which reside in between the two wing hold down bolts and fit in the recess of the hold down plate. When mounted, the wing servos sit just forward of the aux Rx and aft of the battery/esc plate.

The radio tray was installed at the tuck line level in order to locate the elevator pushrod on the thrust line and parallel all the way to the control horns on the elevators. I would recommend lowering this another 3/8" - 1/2" in order to provide more clearance for pushrods among the different controls. As it is, everthing clears but just so.

The Battery/ESC plate was cut to 15 x 3 cm and installed on the thrust line. While it would ideally be a little lower in the fuse to locate the battery's CG in line with the motor (taking into account the thickness of the battery), it turns out this is the perfect location from a layout standpoint. The ESC sits on the underside in between F2 and the front of the plate leaving some room in the front for mounting screws and rails. The battery sits atop the plate and can be moved back and forth about half a battery length - hopefully this will be enough to locate correct CG. As it stands, it feels like the model will balance nicely with the battery located more forward where convenient for swapout.

I installed the radio tray with a single cross rail in the front and two sliders on each side at the rear into which the tray slides in. A single servo screw holds the plate down on the cross rail preventing the tray from shifting in any direction. For the battery/esc tray, two simple cross rails hold it in place with the rail on top in the rear (screwed down from beneath) and on the bottom on the front (screwed down from the top battery/motor bay. The firewall will be bonded in place in front of the tray and will hold the motor in a conventional manner with standoffs. I'm hoping the prop adapter will be sufficiently long to allow me to keep the can further back and away from the nose ring. If needed, the nose ring can be widened another 5 mm in diameter to provide ~4mm clearance around the motor can. This is just the front end where the motor approaches the nose rings. Ample space behind the rings is available for the can to rotate without binding from the fuse chin or canopy (hollowed out as per plans).

Whew! That should be enough for one post. Here are some pics. As mentioned, the location of the Rx's as shown is not final. Ialso set the servo installation up with HS-55's which Ihad around but will likely be replaced before the maiden for better ones (of the same dimension).

David.

doxilia

My Feedback: (3)

As well as almost finishing the wing (front fuse section missing), Ialso completed the fin/rudder assembly with the fin tip and subfin installed, shaped and the rudder fully hinged now. As can be seen on some shots, Imanaged to be careless on just one pass of 80 grit and needed to use a little filler on the fin sides to even things out. Working on such small surfaces with very little wood tolerance makes things tricky not to mention that the airframe is practically weightless (it has to be held down with lead shot so it can be worked on).

I mounted the wing in the back with two 6-32 nylon screws and recessed nylon washers but will replace these for 8-32 screws as the former feel a little flexy - wouldn't want the heads popping off (in flight or when umounting the wing - that would be a PITA - requiring them to be drilled out)! The front two dowels will be installed next, now that Ihave popped off the canopy and have access to the front of F2 (whew! - tricky to align right without access.) Then, I'll work on the wing fillets.

I can also proceed to mount the canopy which I'll actually do with a single 4-40 x 1/2" screw and blind nut in the rear (instead of magnets which I don't have) through small 1/16" plates. The front will have two dowels into the nose ring.

Once that's done, there won't be too much more Ican do until I receive the motor as I want to delay mounting the stab until Iproduce the tuck lines (for ease of sanding). The latter require the final fuse width and side to canopy continuity to be finalized. I'll probably go ahead and install the control horns in the rear awaiting linkages. My list of things to do prior to covering is actually 15 items long... I'm sure I'll manage to add a few more things (there's always something).

Below are some assembled progress shots (plan in background on wall is of 60 size Tipo). Getting close!

David.

doxilia

My Feedback: (3)

Bookeeping...

last I weighed the airframe it stood at 11 oz even (6 oz wing, 5 oz fuse/empennage) - nice!

After I installed the assorted radio, battery, esc and support plates an even 10 oz were added bringing the weight to 21 oz. Wing fillets, wing fuse section, firewall and motor (71 g = 2.5 oz) installation as well as linkages will likely add another 5 oz max leaving me with a 26 oz AUW model prior to covering.

Question is, how much weight will be added by the covering?I'll make a final decision on what covering to use based on the final uncovered AUW figure. I'm inclined to go with the cheapest solution of all - Monokote. Why? Because it's sitting rolled up beside the bench!

Trim scheme will be simple and classic...

David.

P.S. Ishould mention that the ESC that Imounted in my weighed measurements is actually a CC TB54A ESC (1.3 oz) rather than the 36A (0.7 oz) which is all that's needed. The weight savings would be of 0.5 oz - it all counts!

alcarafa

PICOis looking great David, it's a wise desicion to use a stronger servo, HS55 gears are actually very weak ones.
Im sure you find out how hard it is to work in such a narrow fuse like this one not an easytask right?
That's why I installed aileron servos on the wings, there was not enough room for Rx AR7000, batteries, switch,fuel tank etc.

Itlooks like you'r going to finish this one soon you wont regret it, this lil missile perfomance is outstanding!!!!

doxilia

My Feedback: (3)

Thanks Rafa. Yup, she should be ready pretty soon!

How's yours coming along? Is the wing done?

I'm back on the search for good micro servos. Although the Futuaba 3114's seem to be a good servo for the price, I'm debating about doing better. Iwish JR had something that convinced me but neither the 285's nor 290's do and they are a tad expensive. Other options include the Futaba 3157 and the E-flite DS75 - actually seems to be a nice low weight digital servo with decent speed and torque for a good price. It might be something to try, I'm just not sure they are much better than the HS-55's gear wise.

It is very rare for me to install aileron servo's in the wing center with torque rods especially if I'm going to use two servos. In this case though, Iwanted to avoid having exposed linkages on the wing bottom (and don't like seeing linkages on the top) in order to avoid snagging and possible ripout on landing - remember there are no wheels on this pocket rocket! Still, I'm finding it quite amazing that everything fits in close proximity and I can see that a retract nose gear would fit in the space under the ESC. But, Idecided to leave retracts as a Nanorare feature as Iwas a little tired of working on wing wheel wells (4 in a row...)

Now, I'm just debating on whether to switch the aircraft via the ESC to Rx connection to arm the rocket or to do it in the safer Battery to ESC jumper fashion. I'm actually unsure what the status of an ESCis when plugged into power but not into a Rx for control. Perhaps Andy could shed some light on whether it is safe to switch an ESC via its Rx lead (i.e., no potential for prop turning). Iseem to recall that E-flite ESC's have a switching Rx lead so it's perhaps safe to put a 3 lead switch inline with the ESC to Rx lead.

Electric has its dangers... it doesn't take much for that prop to turn, especially on some ESC's. Castle's don't requiring moving the throttle stick for arming which is something that one needs to do on Electrifly ESC's.

David.

rainedave

My Feedback: (1)

Looking Awesome! That is a very light airframe.

I agree that the HS-55's are too fragile. I'd use HS-65HD's, HS-81's or the newer HS-82's.

Can't wait for the flight report. BTW, have you considered dope and Jap tissue? Or, maybe one of the traditional free flight coverings like Polyspan, Litespan or Airspan?

http://www.faimodelsupply.com/starline-polyspan.htm

http://www.peck-polymers.com/html/covering.asp

My Super Kaos Jr. is covered with dope and tissue.

David

doxilia

My Feedback: (3)

Thanks David!

Yup, she is turning out to be a nice electric (big) park flyer. Today I spotted a park a couple of miles from my place that I had no clue existed. It might just be the ideal size for a casual evening spin up with my boy!

Thanks also for the classic finishing suggestions. It's been a long time since I've used tissue and dope - 30 years perhaps. Iwanted to avoid painting (although it would be nice - it always is) as the goal was to expedite this one. Simple, quick and inexpensive. I'll probably throw paint into the mix as Imove up in scale starting with the Nanorare perhaps. The glow version of that will probably come along next with a couple of modifications I have in mind. As a hint of what I 'm thinking of, I might rename it the Mirage (Ithought it was a cool name that popped into my head today).

I'll be going up the torque scale with the servos although I'm considering leaving the 55's on the ailerons as there is 1 each there and just swap out the tail servos.

Wonderful job on your SK Jr.! She's a beauty. Specs?

David.

doxilia

My Feedback: (3)

Nothing major to report this evening other than the great news that the first couple of Pico specific DS motors in Canada (2dog doesn't yet have them either) have arrived in Edmonton. They'll be shipped tomorrow and should be here by week end. Can't wait to spin them up!

I did make some progress though. I completed the wing mounting with a couple of dowels buried into the core with Gorilla glue. Ibacked the 1/16" ply tight dowel holes in F2 with a chunk of triangle stock (these little details chew away the time) so everything is solid there. Iwent to the hardware store to pick up a few nylon screws to no avail - they no longer carry them I'll have to source myself some #8-32 screws elsewhere for the wing rear (#6-32 Ihave at the moment aren't meaty enough). Ialso got the wing fillets sorted out using 1/64" ply plates lathered with a rich mix of epoxy and microballoons and alcohol. Slapped the paste on and smoothed it down in traditional style. This provided a base for some additional white hobby filler which will finish off the job after a little sanding, hardening and final sanding. Tomorrow I'll work on the underside of the wing center and build up the LE fuse section and finish off the TE area nicely.

I also got some cooling intake and exhaust openings taken care of. The chin's done and so's the fuse rear exhaust. Missing are the canopy ducts as well as mounting this to the fuse (where's that motor!). On second look, it might be nicer to round the edges of the cooling ducts to produce a more laminar airflow entering and exiting the fuse. Control horns in the tail are also installed - simple:a pair of small nylon horns and a DB 2-56 P-P horn which I'm not convinced of. I might have to do something a little different there.

Despite my own probably good advice and enthused by the arrival of the motors (Ibought two - hopefully they'll work out!), I also comenced working on the side tucks. These will be hard to appreciate in pictures until the model is covered.

David.

doxilia

My Feedback: (3)

I took a couple of cool good night Pico shots prior to closing up shop for the night.

A few more evenings and she'll be ready for some colours!

Hmm... actually you can almost see the side tucks in these - still just a start.

David.

doxilia

My Feedback: (3)

Nothing major to report tonight (again) as the motors are still in transit

I did get the canopy mounted with two very small hardwood dowels into the nose ring and it's held down with a simple washered servo screw which bottoms out on a 1/16" penny sized plate and bites into a piece of 1/8" lite ply attached to the underside of the top sheeting at the rear canopy/fuse junction.

The wing fillets are almost done. Another pass of filler and sanding and they'll be nice and smooth. I also finished the little annoying front fuse section at the wing center LE as well as tidied things up at the rear wing/fuse junction where the fairings join the fuse.

There's always a little more sanding to be done or something but until I have the motor, I'm pretty much done. I guess I'll go ahead and mount the stab tomorrow even though it makes final shaping of the tuck lines a little harder (can't rest the fuse on its side but I'll use a cradle).

I found some nifty aluminum spacers for the motor which hopefully will work nicely. They're 8-32 sized and tap right into the FW. For safety, I'll back them with some lock nuts. The front spaces the mounting cross with a couple of nylon washers (helps to keep the motor noise limited to the spinning prop) and a lock washer. The setup should help to add some weight to the nose which I think will be needed but we'll see.

David.

doxilia

My Feedback: (3)

Oh... with the wing fillets and some hardware and plates, I managed to bring the airframe up to 12 oz (those treacherous wing fillets!) - probably 1/2 oz in epoxy, microballons and filler.

With the stab mounted and filleted and a couple of reinforcements to the front section (I've decided to add some tri stock and a couple of balsa doublers in vertical grain where the front holes are) once the FW is hollowed out and mounted, I'll probably end up with a 12.5 oz airframe.

This is leading me to think I might have a ~16 oz finished airframe. Add 10 oz of gear and we'll have a nice 26 oz RTF mini ballistic pattern ship!

David.