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Old Mar 04, 2013, 10:13 AM
Air Assassin
RogueAce's Avatar
United States, FL, Pompano Beach
Joined Oct 2012
353 Posts
That's what I did Mark. I used the 3/4oz glass on the bottom and just the resin on rest of plane. The poly/talc was just for smoothe finsh. Either way the unit wasn't up to snuff to carry the plane. I believe that even with a smaller inlet that the plane would have been flyable ,yet waayyy underpowered. I'll try my best to either put in new motor to increase power, or replace w/64mm.
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Old Mar 04, 2013, 01:24 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,199 Posts
That's a shame.If you moved the fan forward,could the nose weight be reduced?I'm guessing if you go to 64 you'll need to add more?
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Old Mar 04, 2013, 01:44 PM
Air Assassin
RogueAce's Avatar
United States, FL, Pompano Beach
Joined Oct 2012
353 Posts
I'm thinkin' that if I go 64mm that the inlet may be ok,if not I have an idea how to fix. And the batt location should be good for weight. I took the extra weight out after 1st toss today. Second toss was a farther glide but I could see that she didn't have the power. 3rd and 4th just confirmed..LOL..and added damage.
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Old Mar 04, 2013, 03:27 PM
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sloperjoe's Avatar
United States, WA, Vancouver
Joined Mar 2012
739 Posts
sorry to hear about the maiden.
if I could suggest a way to go I would...
go liter
instead of a bigger fan, go with a smaller ESC, smaller batts, and liten the airframe up. if you use a 3 layer wing you wont need to put a spar in it, resist the urge to add wood or glass, sometimes reinforcement just adds weight that just might not be needed.
the Mig I just finished is a floater, very lite, small batts, small ESC, no reinforcement used other than a thin coat of 5min epoxy on the intake mouth. the 7800KV motor worked out nicely, I can run it on a 2S 1000mah pack, even at 75% throttle its hauling pretty good, WOT is wild! 40% keeps it in the air easily, the sound is really cool, way quieter and more of a low thrum tone as opposed to the high pitch scream of my stock SkyAngels F-86.
I'am thinking weight was your enemy here more than intake size.
just keep trying it'll fly

Joe
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Old Mar 04, 2013, 04:06 PM
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RogueAce's Avatar
United States, FL, Pompano Beach
Joined Oct 2012
353 Posts
Thanx for the input and encouragement Joe. LOL.weight and gravity combined with a self designed airframe!! I'm going to try and NOT have to scrap her. Getting to the unit itself will be some serious surgery. Not sure how to lighten an already epoxied airframe....any clues???
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Old Mar 05, 2013, 02:42 AM
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sloperjoe's Avatar
United States, WA, Vancouver
Joined Mar 2012
739 Posts
nobody likes to hear it but all I can say is build another airframe,..
a 25" wing span airframe is going to at the very least struggle to fly the weight you have on it. the 2200mah 3s battery is pretty big for this size plane, you have a 4300KV motor on your fan so you should be able to go with a high C rated 1000 or 1300 pack, if I read the specs on your fan right it should pull 18amps max so the 60amp ESC is overkill, go with a 20-25 amp rated unit with an onboard bec so you can eliminate that too. if you went with a 3 layer wing laminated with 3M-77 you could still use a spar if you wanted just go with a 5mm X 2-3mm thick CF beam type so you can tuck it into the middle layer, this would stiffen it nicely while not adding hardly any weight, go a bit smaller on the tail plane size, maybe add a layer more foam to the fuse to round it off better while making it stronger, you could eliminate 2 of the 4 servos, you were guesstimating 1.5-2lbs ready to fly my 70mm Phantom weighs like 24oz ready to fly. you should be able to build this airframe to about 12-14oz ready to fly, just need to resist the urge to reinforce. go lite, think lite, build lite, and your smile will be brite

Joe
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Old Mar 05, 2013, 05:59 PM
James L
TANGOSIERRAROM's Avatar
Beck Row Mildenhall
Joined Mar 2009
789 Posts
Easiest solution of the motor will take the Amperage about 30 is to go to 4s 4300 will take a 4s battery in a 55 mm fan and should give a decent thrust increase. You will move to about 400 watts which should you about 27 oz of thrust. Have a look at Dons RC http://www.donsrc.com/cart/index.php...&product_id=62

I have a 24" wingspan model that is 53" long and runs on 2 55mm fans AUW is 38.8 oz 1100 grams thrust is 1200 grams 42Oz and it flies very nicely. So weight although a bit of an issue is not your only enemy but the real problem lies with a lack of thrust compared to your weight and wing loading. .
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Old Mar 07, 2013, 12:06 PM
Registered User
Canada
Joined Nov 2000
6,869 Posts
Sometimes it's simpler/quicker to redo the model from scratch.
Second tries (for me at least) are much less work because it's only assembly, no more stopping to figure out each detail.. before you can build it.
G'luck
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Old Mar 07, 2013, 12:15 PM
Do it Right, the first time!
CoolerByTheLake's Avatar
United States, MN, Hermantown
Joined Dec 2008
5,010 Posts
I have always tended to build a little heavy myself, but getting better at it. I remember sometime ago reading some sage advice here -- Build to fly not to crash!
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Old Mar 11, 2013, 12:59 PM
Air Assassin
RogueAce's Avatar
United States, FL, Pompano Beach
Joined Oct 2012
353 Posts
Had an entire week away from bench. Time to strip the Sabre. From plane to parts in mere minutes. I am getting tired of collecting momentos of lost planes and filling the trash can with hard work ! LOL...at least the Bandit had a full flight before ESC cut out and she nosed in. The other 2 never made a flight.
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Old Mar 11, 2013, 01:14 PM
Do it Right, the first time!
CoolerByTheLake's Avatar
United States, MN, Hermantown
Joined Dec 2008
5,010 Posts
Nice momentos, are you building a display case for them? I'm sure it won't be long until you unveil the "new inproved" Sabre!!
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Old Mar 12, 2013, 06:51 AM
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USA
Joined Apr 2007
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build profile elev&rudder only
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Old Mar 12, 2013, 08:02 AM
Air Assassin
RogueAce's Avatar
United States, FL, Pompano Beach
Joined Oct 2012
353 Posts
Sorry Space1,but I don't like profiles,I like full fuse planes. I've seen tons of profiles that are good fliers..but I have never liked the look of them...prop or edf.
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Old Mar 12, 2013, 12:15 PM
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Canada
Joined Nov 2000
6,869 Posts
OK.. what ever blows yer jets.. but the operative word there was "Fliers" :-)
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Old Mar 12, 2013, 01:23 PM
Air Assassin
RogueAce's Avatar
United States, FL, Pompano Beach
Joined Oct 2012
353 Posts
Truth is the only profile plane I've ever seen ,flown or liked was the balsa one that you throw or the one you wind up w/rubber band. When someone else is footin' the bill....then maybe I'll build one, 'til then, I'll build what I like, and that is full fuse planes. LOL....and it will fly!!! They will all soon fly!!
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