Lumenier RB2205C-12 2400KV SKITZO Ceramic Bearing Motor
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Old Dec 11, 2006, 08:31 AM
jalves is offline
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Folks,

I'm trying to do some torque roll with the AM (himax 3516-840, APCe13x6,5, 3s), have the CG at 11cm (IIRC), but the plane can't sustain a stable hover long enough.

What deflections (ailerons, elevators, rudder) are you using in the AM?
Are you using expo, How much? And dual rates??

TIA

Jorge
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Old Dec 11, 2006, 09:19 AM
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Jorge,
I have not fly it much long (as stated and you already know) but... 11 cm seems to me a too much conservative CG. I flew first time at 11cm, but go to 12cm for the following flights, and was ok, needing the smallest of "push" on elevator in inverted.
As for my "accident"... I still believe something was wrong on my fuse, but yes, the frame is not "robust" son it is far from able to take "any abuse"... even if I consider having not abused it...
Saludos
Josep
Old Dec 11, 2006, 09:30 AM
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Quote:
Originally Posted by armengol
Hi guys,
New to this thread, looking for the 100th page!
Unfortunately I am here with sad news. After many weeks looking at the box past week I had the time to assemble my AM, everything went ok, I put an Axi 2820/10 on it, test some props and packs, and went for a 12'2x3'75 (fun fly .46 tyipical prop) with lipo 3s or 13x4 with A123 3s (a bit less voltage), all APCs.
Ok, maiden on saturday with strong winds, but everything went OK. A real nice plane, even in those uncomfortable conditions.
Sunday came with almost no wind and nice sun, so the AM go. Two more flights on it, everything really nice. How I liked.
Then came the third fly, and after some inverted barrel action, when cruising along to relax a bit... something went wrong: the fuse front end broke and the motor went away. Fortunately the pack showed on the front balancing it somewhat and the plane landed nicely, but still looking for my beloved 2820/10...
If you look at the broken front (pics enclosed) I see this is really TOO FRAGILE. Too small thickness of material here, this is elapor, not a solid thing. I will repair, but this plane need some tape or reinforcements here.... or had I a defective one and am alone on this? (my props are well balanced and everything sounded nice and right btw).
Regards
Josep
Such a catastrophic failure may well have been caused by the loss of a prop blade. The resulting out of balance forces would certainly be sufficient.

Tony
Old Dec 11, 2006, 09:55 AM
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Tony,
I agree, but... not here. As stated I have yet to find the motor & prop, but you do hear such a thing, and believe me, my prop was well and healthy. If you know them, the Apc 12'2x3'75 are robust...
Josep
Old Dec 11, 2006, 10:28 AM
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The mass momentun of the prop is enough to rip the front of the model . I think they choose a small prop with this thing in mind , all we know a bigger prop performs better but they also know the loads it take . Look at this:
http://www.rotax-owner.com/si_tb_inf...nfo/11ul91.pdf

The document show how to calculate the propeller mass moment of inertia for not to cross the limits. A prop when stationary spun does not put any side loads but when the disc is fliped ,gyroscopic forces act , the heavier and the quickier it turns ,the worse is the effect .

Saludos y buena suerte en la busqueda.
Old Dec 11, 2006, 10:51 AM
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(gracias)
Now I can agree, the problem arrived after a barrel, with motor on, so the inertias must have been too big.
But then... they must put a big warning on not to use a too big prop, right?
Btw, is there in this long thread a reference to this problem already? I have not found it... I admit I must have no seen but... after almost 99 pages...
Regards
Josep
Old Dec 11, 2006, 01:02 PM
blucor basher is online now
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Slightly overpowered motor spinning a way too heavy prop...I think chichisport is right.
Old Dec 11, 2006, 01:10 PM
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I just started the construction of my Acromaster...I read in an earlier post that there were concerns about the motor mount blocking off the cooling holes of various motors. Any heat-related issues with the Torque 2818-900?

I really didn't like the way the spacer, in particular, blocked off the cooling holes on the front of the Torque motor. I broke out the dremel and carved a relief in between each mounting hole, allowing at least some airflow through the front of the motor...what do you think--worthwhile mod?

Blucor Basher--any update on the "new and improved" motor mounts yet?
Old Dec 11, 2006, 01:19 PM
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I don't personally have heat problems on either the Torque or the Power10,

As to the mounts, it would be easy to produce a plate with additional cooling, but very difficult to incorporate the factory thrust line-adjusting mechanism. Additional projects and travel schedules (not to mention the usual holiday rush) mean that we probably won't be able to burn any new mounts for the the AM until after the holidays.
Old Dec 11, 2006, 02:05 PM
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My 2818/900 has the spacer with no cooling holes cut in. Using a 1365e prop, it never gets warm, and I fly the FOAM (for lack of better 4 letter verbatum) out of this plane. The 2100pl and AirBoss come down very slightly warm, that's about it. The fat wing on this thing makes it fly so SICK!!!! 3rd flight had me doing inverted harriers on the deck with the wind a blowin'. TR's look cool as the plane floats away laterally spinning like a top. I think we have a winner!
Mike
Old Dec 11, 2006, 02:37 PM
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Hey guys, I'm thinking about how best to save weight on this plane. Do you think that it would be a good idea to cut back the tail surfaces to about 75% their size, as well as trim the wings to about 75%, and carve out some of the volume in the fuse as well? I want this thing to be super light.
Old Dec 11, 2006, 02:54 PM
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You could try a planet with less gravity.
Old Dec 11, 2006, 03:19 PM
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Quote:
Originally Posted by skiermike123
Hey guys, I'm thinking about how best to save weight on this plane. Do you think that it would be a good idea to cut back the tail surfaces to about 75% their size, as well as trim the wings to about 75%, and carve out some of the volume in the fuse as well? I want this thing to be super light.
The wings are the last place you wanna remove material from. You may make it lighter, but the wing loading will certainly go up by taking away square inches of wing.


Brian
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Old Dec 11, 2006, 03:20 PM
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Quote:
Originally Posted by Padesatka
You could try a planet with less gravity.
Ooh, I like that idea, keep me posted
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Old Dec 11, 2006, 04:18 PM
skiermike123 is offline
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Well, I was thinking about using a large braided rubber band instead of a motor and some fishing line instead of pushrods. Do you think it would fly pretty good?


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