4 stroken ron

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TMan: YEAH, YEAH, YEAH, practice, pratice, pratice, I know. But it is way more fun to just blow holes in the sky.
Can you tell me what size shaft is on your COOL S drive? If it is a 4MM shaft it uses GWS 400 gears and if it is a 3MM shaft it uses GWS 350 gears. This will tell me which gears to order.
Thanks
Ron

TManiaci

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I am fairly sure it's 3 mm. I'll have to measure agian tonight when I get home to be absolutely sure.

cwrr5

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Update on mine... got everything put together, except for the pushrods. Also still need to lengthen the servo leads and build a "Y" for the aileron servos. (I decided to use two aileron servos afterall, but I moved them to the top of the wing). Gotta charge batteries and final install on the speed control&receiver and add some packing tape to the belly. I'm searching for something I can use to slighly stiffen the fuselage (between wing&tail), I don't like that much flex in that area. I also had to glue the wingtips and nose section back together, and the turtle deck has somehow popped open,which is actually a good thing, as now I can reach the servo wires. I got the string snagged on something and pulled it out before I ran the wiring.

When I pick it up, the fuselage sags like a dead fish. [:'(]

I gotta say, I'm REALLY not impressed with this thing so far, but I'll give it a try just to be fair. Maiden flight & pics to follow tomorrow if time permits- hopefully.

TManiaci

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Good luck Cwrr5, and thanks for your sacrifice over there in Sand-Land!!!

Hey, look around for some bamboo shishkabob skewers, but if you can't find anything to stiffen, sreatching tape on the sides will stiffen it up a bit...

Hang with it, you'll come to like it. It's not too bad for a nerf toy.

aflipz

My Feedback: (10)

Yeah, in the upper pages of this thread i actually have pictures of the ''surgery'' involving common bamboo skewers. believe me it works better than it sounds... Mine have survived the worst possible crash and those are the only parts of the plane that remained unscathed. I think you'll be pretty happy with it, once you stiffen it up and give it more climbing power it's a blast to fly. I'm optimistic both you and your aircraft will come back to america in one piece.

zip that turtle deck back together with hot glue when you are done passing the wires and stiffening the frame! You can easily go back in there (or anywhere on the plane) by running a glue gun at low temp to melt the glue and separate the parts. Just clean the glug gun thoroughly between colors and white sections because it's gonna bleed all over and look messy.

TManiaci

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Hey cwrr5, I bet it's so hot there you don't need a hot glue gun... ever hear of a guy named Icarus? [sm=lol.gif]

Maybe there is a nice C5 Galaxy nearby you can fly inside of...

aflipz

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Let's make things more interesting, Fly inside the c5 galaxy while it flies in parabellums!

cwrr5

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Tman - I had that same thought yesterday!!! 120+ and HUMID! yuck! Going to be flying at night... it cools off to around 100-ish

Aflipz, LOL! No freds to be found here, just herks. I don't think the plane is going to make it back with me later this year [>:] (I test to destruction )
Figured out the colors bleeding the hard way yesterday, oh well, it's not too bad looking.
I can get bamboo skewers, just gotta get to the bx before going to work. I "acquired" a small piece of aluminum tubing, but after some more thought, figured that might be a little over the top(and slightly dangerous - flying metal spear... not so good. [sm=tired.gif] )

No progress tonight, gotta fix my 1:1 scale models.

aflipz

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test away*, as long as you find all the pieces and have the patience to put em back together she'll make it back... Like tman said this is a ''nerf''plane.

Haven't flown in 8 days on the count of 2 faulty esc'e being replaced by their manufacturers. I am having serious withdrawal issues.



* of course assuming this testing does not involve bazooka practice or other explosives of any kind being shot at or straped onto the aircraft, of course if that's going to be the case please get someone to take a video cos me wanna see!!!

cwrr5

My Feedback: (32)

ROFL! I'd like to see that too!

First (and second and third) flight sucessfull tonight!!! I did dork it pretty good on the second flight when I lost orientation low&slow, but it was a quick fix. Just had some cracks in the wing foam right at the fuselage, on both sides, and the prop came off(as designed). Nothing a dab or four of hot glue couldn't fix.

Got two pictures, but they didn't turn out too good, and no inflight shots. My "cameraman" was giving me advise and watching instead of taking pictures. [&:]
We'll try again tomorrow during the day.

aflipz

My Feedback: (10)

Great news, that means you are having fun with the plane. Think of it this way, the hot glue you added gave it some more structural integrity

Hint, after a few hits the ribs inside the wings crack and get detached from the airfoil, ''open airfoil surgery'' restores airfoil stiffness allowing you to have fun with it longer...

Guys, i broke down, ordered pot009 from my lhs. I am reffering to a potensky cobra foam only airplane. Can't wait to see how i'll do, apparently the instructions are pretty bad and there are a lot of technical parts to this build. But what the heck i got a pretty good idea what a plane is supposed to look like...

my only concern is with the weight of my 3s 2100 tp pack in that plane, hope it isn't too much, it was designed for 2s. Then again the ucd was designed for 1320's or 1500's and i'm getting great flights with the 2100's (when i have a friggi'n esc i can use...) so how bad can 40g extra be? (counting the brushless motor weight reduction should be around 40g)

4 stroken ron

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Well at least you are waiting on a worthwhile part. I am waiting on a friggin spur gear.
Ron

TManiaci

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Congrats on a successful maiden rr5... hope you had FUN.

As for the heavy battery... you won't believe it till you try it, but a light plane flys all-together different (I mean way better). The 3D perfomance of a plane is HEAVILY dependent on a light wing loading. So, if you have not flown on a "small" battery (light) you can't even appreciate how much BETTER it really is.

My favorite small plane in my stable is that Yak I keep yaking about (punn intended). I fly that with a TP1320 also, at the same weight as this UCD. I put my son's TP720 in it (weight about half) and OH-MY-GOD, the performance is like 3 times BETTER. Yea, it won't fly as long, but it flies so much better it's worth the sacrifice of time.

The moral of this story is... LIGHT is BETTER, and you really need to make that your mantra when building and buying. I'm dieing to steal my boy's TP730 and try it in the UCD... I bet it will be a BLAST to fly then... and guess what, it won't cause near the damage when you crash a lighter plane (less inertia). Just gotta be careful about overloading with long WOT bursts. Measure the current where you get a stick position for around 9 amps (12C on a TP720) and stay at or below that, no problems then.

I will tell you how important this is... on the big nitro planes, we spend hundreds of $$$ to take out a few measley ounces on a 10lb bird. Yes, it's worth it if you are hardcore on perfomance. Me, not that good that it's critical yet, but I have spent a good bit heading that direction on my F90. CF landing gear, lightweight wheels and axles, Lipoly battery power with regulation, smaller Rx, CF pushrods, smaller high-torque servos, etc., etc., etc.

aflipz

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I just found some interesting info, the cobra only has 240 sq inches of wing area compared to 369 for the ucd. This is great news for me in a way, i allways had a fancy for the smaller scale rc (1/24 and 1/18 cars and trucks) But youre right i'm gonna have to get a considerably lighter pack in there. they recommend a 2s 2100 pack that weighs 95 grams,(for use on their speed 300 type motor) i'm thinking a 3s 1320 tp that comes in at 85 grams. With a 17 amp contimuous and 27 amp burst it's still got a little margin over what i want to pull from it. Not only that, i'll shorten any unnecessary wire, replace heavy connectors with direct solder+shrinkwrap, use no gearbox and a lighter motor. Now we should be in business at 25-30 grams under requirements. Gonna look into 5 gram servos too. shaving another 16 grams. Just to leave some room for the repair adhesives...

I thought a bit more weight made the model less sensitive to wind and just need more airspeed to stay aloft. Oh well, lighter is better, as you can see i'm eager to give it a try. Looks like i'll take my time building this one, having something else ready to fly will keep me busy.

and ron, that blows man, if you were nearby i'd give you mine it's not like i plan on using it anytime soon...

cwrr5

My Feedback: (32)

Thanks for the tip Aflipz, I'll keep an eye on it.... definitely fun, but I'm still a little dubious on the durability of this thing. 3 flights, and it looks like it went through a washing machine with rocks&dirt.

Didn't do much 3d with it yet, it was a little breezy, and I'm still wringing it out.
I did end up installing the aluminum tube from the rear of the cockpit to the tail section, evidently it doesn't add too much weight(actually balances it slightly tail heavy [sm=thumbup.gif] )

Light is definitely better, and you end up with less damage when they hit the ground (and they all do eventually), but it's a compromise when it comes to strength.

cwrr5

My Feedback: (32)

Update: Three more good flights tonight, working into some light 3D stuff as I get more comfortable with it. As I mentioned earlier, I'm not using a computer radio so I have no EPA, dual rates, mixing, or anything else - just basic four channels. The setup is extremely sensitive (pushrods are in the middle holes). Hovering is a piece of cake, almost effortless, and has plenty of power with my setup for a vertical hold and release launch. I'm somewhat happier with it now that I have some more flight time on it, but still not real wild about the construction. I think GP could have done better - especially with the cheesy pushrods and control horns. I managed to snap two of them during the install, but CA fixed that quick. I have some fine tuning to do with the balance, it seems to want to pull to the left during harriers and loops, but vertical climbs are fine. It seems to also want to "tuck" towards the belly in a dive, especially with a little power on. Minor details...

The "peanut gallery" has been giving me a round of applause after each landing, and I've gotten several to start yelling "LOWER!" when it's down&dirty "huckin it on the deck".

Anyone else getting a lot of wing flex during pull ups, especially hard ones? I'm contmplating beefing up the wing somehow, but do NOT want to add weight. []

aflipz

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Well, Stiffening without ANY weight addition is absolutely impossible imho, unless you remove the existing materials and replace them with lighter and stiffer ones wich would be a challenge to say the least on the ucd.

What did ot for me, at a low weight cost 2 bamboo skewers inside each wing, glued to the ribs inside the wing, glued paralel to the existing cf rods on top and bottom of the wing (the ones that finish where your wings starts bending) And finally glued to the upper and lower wing sections, it's very very stiff but will bend and regain shape in a hard crash. with my brushless power and heavier batteries even pulling out of a wot dive (trying to push the speed envelope) i am unable to get the wings to bend up. If i remember correctly each skewer weighed like 1.1-1.5g or something, could have been less and too lazy to look. it was fresher in my memory when i wrote a big post about it in this thread. Must have taken a couple of grams of glue to do it...

Still waiting on esc's to get back in the air, suck to be me; another flightless weekend...

with your pack in place, if you hold your plane up by the palms of your hands near the wingtips, if you bounce it up and down hard enough you will see where they bend, just past the cf rods, mine no longer does this.


My cobra will not either, it comes with dual cf rods for both wings and fuselage and they go all the way... Plus it looks allmost scale, i can't wait!!!

4 stroken ron

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TMan: I got the "WOW" motor today and did some tests. I sure got different results
then the web site stated.
http://www.nesail.com/detail.php?productID=3453
This is what the web site stated.

"It is 4.4-1 gear ratio which is perfect for a 10 x 4.7 GWS prop. The motor
is 4200 Kv and with the 4.4- to 1 geardrive is ideal for many applications.
The motor and gear drive with the speed control produce over 24 ounces of
thrust! This is with a 3 cell 2100 Li-poly battery as tested. With an APC
prop we get 16 amps static."

I used a 10X4.7 prop and my Madusa showed 17.4 Amps at WFO (172 watts) and
my postal scale showed 21 oz. of thrust. They also state they use a 3 cell
2100 mil LiPo. I used a 1500 3 cell. Is it common for results to vary that
much? Does that seem like a lot of AMP draw for that amount of watts? They
don't state anything about RPM. I got 6600. What is the limit for these GWS
props? OBTW it has a brake, seems to be set kind of hard. It stops it
pretty suddenly. The brake setting cannot be changed. Also the price has
come down. Last week it was $57.99, this week it is $50.00.
I weighed the motor with prop, connectors and ESC. It weighs 3.6 oz. (105 grams)
I also weighed the stock UCNDO 280 brushed motor with CC 20P ESC and connectors
and interestingly enough, it weighs 3.6oz also.
Here is the specs on the stock brushed motor that came with the UCANDO, except it
now has GWS 350 "C" gears, 5.33 to 1
Same prop and battery, AMPS 10.9 watts 119, thrust 19.1 oz
So it looks like I spent $70.99 (including connectors and freight) for a brushless
motor and ESC that weighs the same as the stock motor and produces 1.9oz more thrust
than the stock motor, but uses 6.5 more amps to do it.
That seems like a lot to pay in $ and AMPS to get 1.9 oz of thrust.
I will fly tomorrow night, that will be the real test.
Ron

TManiaci

My Feedback: (6)

Ron,

Well, you could explain that by the "C" rating on the battery. If they tested with a 7C battery, a 2100 mAh would only deliver 14.7 amps and begin to overload above that. When a battery is pushed into overload, the peak rpm fades very quickly, so it now becomes dependent on how long they ran it before taking a reading.

If your 1500 mAh is 10C, 12C or 15C, you could effectively deliver 15A, 18A or 22A respectively. In other words, unless you MATCH the exact battery, you will not match the specified performance. The battery effeciency decays significantly above the rated current draw. Other things like temperature and charge quality have some impact on these numbers too.

Prop thrust is directly dependent on RPM. The"KV" rating is actually RPMs/VOLT delivered to the motor. So, for a given prop turning the same rpm, they should produce the same thrust (with all other factors equal).

Another factor is air-density, and could have a significant effect on varying results. Closer to sea level, more dense air, higher thrust and hence higher current draw. Who knows where those results were gathered. This is a significant factor... 4000ft ASL (above sea level) can reduce thrust 15% from data I have seen.

I wouldn't be concerned with turning the prop too fast. They should easily turn over 10,000 without a problem.

BTW: The APC 10x4.7 turning 6440 rpm equals 22 oz thrust. So, your 6600 rpm reading should be making around 24 ozs thrust. Your fish scale in not accurate... good news. (see [link=http://www.icare-rc.com/plettenberg_freestyle2024.htm]LINK[/link] for supporting data)

You 350 upgrade did a nice job, but again, it's hard to make a comparison with too many unknown variables here. I think the 280 turned out 17-18 ozs at a little over 10 amps.

Don't be discouraged, you have a strong setup now... I think you will be very pleased with that kind of thrust. It will be ballistic in comparison.

4 stroken ron

My Feedback: (29)

Everything you say makes good since. I don't know what the C rating is on my battery. It is an Electrifly that tower sells. It says max discharge is 12A I guess that would make it an 8c. Is that right? Anyway I guess I am pushing it too hard at 17 Amps. Of course I rarely fly at WFO anyway. I have a Sunbeam digital postal scale. I don't have any idea how accurate it is.
Thanks for the info
Ron

TManiaci

My Feedback: (6)

Ron,

Yes, your battery is an 8C according to [link=http://www.electrifly.com/batteries/lithpoly.html]Electrifly[/link], or 8 times the rated 2.1 Amp-hours (2100 mAh). So, your max current rating is 12 amps. Yes, at 17 amps, you are smoking that battery.

Make a note of throttle position at 12 amps and try not to fly over that position for more than a few seconds at a time. The other option is to downsize your prop, probably a 9x3.8 or so should be right. That will extend fly time considerably, but limit WOT power to maybe 18-19 oz thrust. Extended draw at overcurrent will ruin the battery.

This is why a good 12-15C battery is much more expensive... and until we understand these technicalities, we don't buy for performance, thinking big mAh is all we need. It's like putting an expensive turbo on your car, same cubes & weight put out way more juice. It's all a tradeoff... pick your preference.

<edit>

Dymond sells a nice 1500 mAh 12C for $39... [link=http://www.rc-dymond.com/order_batteries_lipol.htm]Dymond Lipoly[/link]. That gets you 18 amps to match the rest of the system.

They also sell a 1500 mAh 15C for $45 if you really want to pump it up with more prop and go rediculously overpowered and pull over 20 amps. Guessing with a 28+ oz thrust with a 12x6 prop...

Electrifly (Tower) has a nice 3S 1250 mAh 15C for $50, again getting you up over 18A capacity. Another possibility if you are looking to buy the right battery for the application, and lighter too...

BTW... you were comparing to the 350, not the 280 motor. Your real gain is better than 1.9 oz thrust. It's probably more on the order of 4-6, depending on how hard you work your battery.

4 stroken ron

My Feedback: (29)

I flew the UCANDO and the WOW motor last night. I put a 9X4.7 prop on and the amps down to 12.0. It flew very well. I broke the prop on a hard landing and don't have another. So this morning I put 6.6.1 gears on it(and a prop saver). WFO with a 11X4.7 prop now draws 13.8 AMPS and it turns at 5700 RPM that give a calculated thrust of 28.8 oz. WOO-HOO That is more like it. When I pull her back to 12.0 amps it still is turning 5300, giving me 24.7 oz. I think the UCANDO will fly well with this combo at 6 to 8 AMP draw.
I fly tonight........I hope the gears hold up...
Ron

TManiaci

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That's really cool Ron. Thumbs up [sm=thumbup.gif].

Those thrust numbers sound a little bit high... where did you get those figures from? Are they calculated or actual measured?

So, compare verticle performance for us, new setup vs. the origonal 280 brushed. How was it?

4 stroken ron

My Feedback: (29)

those are calculated. My postal scale has gone, well......postal.

http://www.gobrushless.com/testing/t...calculator.php

With the 9X4.7 prop preformance wasn't much different than the 280
I'm hoping for much better tonight.
Ron

TManiaci

My Feedback: (6)

Hey, thanks, that's a nice calculator site... in my favorites now!

Good luck, hope it works real well.

We still have not flow the new Dymond COOL S 4200 rig. It sucks to have a real job, work 10 hours a day, commute over an hour home, and have other things in your life that are important taking 99% of the rest of your time up. Then, when the rare opportunity does comes up, the f'ing wind is blowing 900 mph! [:@]

I wanna be an RC-hobo vagrant, build & fly all day... I gotta figure out how to make a living off this sport .