SKYRAY...continued - Page 50 - RC Groups
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Nov 13, 2007, 03:34 PM
Look outside the Square
Boxhead's Avatar
Good Call MS, I have found the 4025 on the 2900kv C20 to be the best prop for the it. I tried it the other day on a 2cell 800 and it performed all right also. Not the grunt as with the 3 cell but Hey it flew and not to shabberly either. Weight is the big key for 2 cell. Hope the Big Kids enjoyed Disney as well.................... hahahahaha

Box
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Nov 13, 2007, 04:05 PM
Use whatcha got!
msmith's Avatar
Quote:
Originally Posted by Boxhead
...Hope the Big Kids enjoyed Disney as well.................... hahahahaha

Box
I think the big kids are still recovering...

Between the week of walking and herding three 3-year-olds, then coming home and getting sick twice in three weeks has me pretty run down... Nothing major, just typical 'this time of the year' colds etc... but it has been enough to keep me from operating at full speed.

We'll get there though... no worries...
Nov 13, 2007, 04:08 PM
AKA Don
2900 Kv C-20 ===The 4X4 should be the ticket on 2S. And yes, it's a bit over the top for 3S! BUT, maybe OK on a cool day with reasonable throttle management.
Nov 13, 2007, 10:04 PM
Long life to foam
You think that its over power the C20? I don't want to be against you but I would share my experience:

I flew my Skyray (both) since the maiden with with the c20 2900kv on 3s the GWS 5030 (few times), 4530 (almost always), 4040 (few times) without hitting the Dualsky 12a esc limit and without smoking anything, so ... Am I just lucky? I have checked the motor, esc and battery heat many times and they did not seem warm (maybe little one or two times) C20 seem to prefer 4530 to 4040 In my opinion (and feeling). BTW I have not put a watt meter on it but it s probably, as you said, near the limit of the c20 2900Kv.

Another thing to consider is that I m not testing or using it on a bench but in the air. Cooling is important. I never fly at wot during a complete battery. Both C20 2900kv are still like new, performing superbly as always

Quote:
Originally Posted by msmith
I remembered something else...


Don't run the 2900kv C20 motor on 3S w/ a 4x4 GWS prop...

I had been running the 4025 prop on 3S as recommended by the StrongRCmotors.com website, but decided to 'see what happens' with the 4040. Didn't launch with it, but ran it up on the tailgate w/ the WattsUp Meter. Quickly got over 12 amps and was approaching 140 watts when I shut it down...

I'd rather not fry the motor so this was a very limited test...
Nov 13, 2007, 10:31 PM
Use whatcha got!
msmith's Avatar
Quote:
Originally Posted by bz1mcr
... with reasonable throttle management.
HA!

Do you realize who you're talking to!?!

heh


My left stick is broken in the 'go' position...
Nov 13, 2007, 10:54 PM
AKA Don
Quote:
Originally Posted by tibalotte
You think that its over power the C20? I don't want to be against you but I would share my experience:

I flew my Skyray (both) since the maiden with with the c20 2900kv on 3s the GWS 5030 (few times), 4530 (almost always), 4040 (few times) without hitting the Dualsky 12a esc limit and without smoking anything, so ... Am I just lucky? I have checked the motor, esc and battery heat many times and they did not seem warm (maybe little one or two times) C20 seem to prefer 4530 to 4040 In my opinion (and feeling). BTW I have not put a watt meter on it but it s probably, as you said, near the limit of the c20 2900Kv.

Another thing to consider is that I m not testing or using it on a bench but in the air. Cooling is important. I never fly at wot during a complete battery. Both C20 2900kv are still like new, performing superbly as always
I am glad to learn your C20 are giving you that kind of performance. Thanks for sharing your experience. And, you are correct that on a low drag plane with good cooling, you can successfully fly combinations that will not survive a static bench test. It would be my "guess" that you are getting close to ultimate performance. In other words, you might not be able to do that on a 100 degree F day. And static testing should never last more than a few seconds.
Keep Having Fun!
Nov 14, 2007, 05:50 AM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
A better alternative to over amping these little beauties, might be to clean UP the airframe(less drag) ...This past Sun. , we put the C-20 on a mini Pete .....,.. we expected blazing speeds ... but the inherent drag of the Pete airframe prevented any Quantum leaps of speed... It WAS FAST!!! , just not as fast as we thought... ...MS would have been disappointed...
Latest blog entry: Lost plans
Nov 15, 2007, 08:14 AM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
Great News !!! we found the old Skyray templates...we flew this one several years back with a geared j250... very smooth at its bigger size...I just need to make the vertical fin a little bigger... Should be easy enough flier with the new BW and lighter lipos...The WS is 28" Length is 36" front to tip of the fin...Nice size...good chance for a bit of decor...
Latest blog entry: Lost plans
Nov 15, 2007, 09:55 AM
treefinder
springer's Avatar
gpw:
Ok, fine, so now you have tempted and enticed us, where are they????

seriously, are they just upscaled from the ones you've already posted, or a different take on the design?

Back to your "clean up the airframe" comment, any guidance on that? Will rounding the leading edges of the pieces provide any detectable benefit? How about fairing around the servos, hiding the rx, esc in a wider (multilayer) fuse? Have you guys tried any of that stuff?
Nov 15, 2007, 10:59 AM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
Sure, tried all that stuff and it works for that few extra mph ...The Ray really doesn't need it except for all out speed (you guys have been talking to MS again ... ) This is more of a scalish' SPORT plane , not intended for speed trials ...with lots of maneuverability , decent speed(and vertical) and simple construction ...the only reason for going with the bigger one is for "smoothness"(that and the old one flew so well)...Probably best to just scale UP the 22" and be done with it ... we know that works ... I'll have to talk to Segraves and see if I'm attempting to do it correctly...maybe we can just get a blown UP version for all to enjoy ...
Latest blog entry: Lost plans
Nov 16, 2007, 04:37 AM
Registered User
plane_spotter's Avatar
Glen, Bill is a top bloke, I'm sure he will help you/us out.

Ash
Nov 16, 2007, 05:19 AM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
Spot , that's for sure...!!! All we need is a proper scale factor for S&T so we don't end UP with a 120 page SkyRay tile print...and an 8 foot airframe ...as if I were to do it ...don't ya' know ... hahahahahahaha
Latest blog entry: Lost plans
Nov 16, 2007, 08:50 AM
Registered User
Quote:
Originally Posted by gpw
Spot , that's for sure...!!! All we need is a proper scale factor for S&T so we don't end UP with a 120 page SkyRay tile print...and an 8 foot airframe ...as if I were to do it ...don't ya' know ... hahahahahahaha
Glen, here's your original PDF (untiled with a special iText program I wrote for untiling multi-page tiled PDFs), then scaled and tiled with ScaleAndTile2, using SF = 1.2727. TLAR tells me it's close to what you want.

Best regards,
Bill Segraves
Latest blog entry: My Email Address
Nov 16, 2007, 09:48 AM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
Seg, what can we say but a BIG THANKS!!!!! The bigger 28" built from the same FFF materials should be proportionally a little lighter, lower wing loading , so a smoother floatier' flier... The old one was, and with the heavier brushed gear motor and nimh... Seg , I'm sure everyone will enjoy this one , Thanks Again!!!
Latest blog entry: Lost plans
Nov 16, 2007, 09:53 AM
Registered User
plane_spotter's Avatar
Bill, looks like you stepped in, in the nick of time before Glen went out to buy some 8 foot foam!!!!!!!!!

Nearly finished my normal Skyray, will add this "biggie" to the list.

Ash


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