HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Dec 11, 2006, 08:31 AM
Registered User
jalves's Avatar
Portugal
Joined Mar 2004
2,641 Posts
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
jalves is online now Find More Posts by jalves
Reply With Quote
Sign up now
to remove ads between posts
Old Dec 11, 2006, 09:19 AM
Registered User
Madrid (Spain)
Joined Oct 2004
484 Posts
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
armengol is offline Find More Posts by armengol
Reply With Quote
Old Dec 11, 2006, 09:30 AM
Registered User
ModelTony's Avatar
Irvine, Scotland
Joined Jun 2004
636 Posts
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
ModelTony is offline Find More Posts by ModelTony
Reply With Quote
Old Dec 11, 2006, 09:55 AM
Registered User
Madrid (Spain)
Joined Oct 2004
484 Posts
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
armengol is offline Find More Posts by armengol
Reply With Quote
Old Dec 11, 2006, 10:28 AM
Registered User
Tenerife,Canary Islands
Joined May 2004
1,673 Posts
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.
chichisport is offline Find More Posts by chichisport
Reply With Quote
Old Dec 11, 2006, 10:51 AM
Registered User
Madrid (Spain)
Joined Oct 2004
484 Posts
(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
armengol is offline Find More Posts by armengol
Reply With Quote
Old Dec 11, 2006, 01:02 PM
blucor basher's Avatar
United States, PA, Lancaster
Joined Jun 2003
24,141 Posts
Slightly overpowered motor spinning a way too heavy prop...I think chichisport is right.
blucor basher is offline Find More Posts by blucor basher
Site Sponsor
Reply With Quote
Old Dec 11, 2006, 01:10 PM
Retired USAF
cynjon's Avatar
USA, SD, Piedmont
Joined Jul 2005
2,910 Posts
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?
cynjon is offline Find More Posts by cynjon
Reply With Quote
Old Dec 11, 2006, 01:19 PM
blucor basher's Avatar
United States, PA, Lancaster
Joined Jun 2003
24,141 Posts
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.
blucor basher is offline Find More Posts by blucor basher
Site Sponsor
Reply With Quote
Old Dec 11, 2006, 02:05 PM
C.H.E.A.P.
MICKEL's Avatar
Chino Hills, CA
Joined Jan 2005
1,494 Posts
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
MICKEL is offline Find More Posts by MICKEL
RCG Plus Member
Latest blog entry: Inverza33
Reply With Quote
Old Dec 11, 2006, 02:37 PM
Registered User
Joined Sep 2006
209 Posts
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.
skiermike123 is offline Find More Posts by skiermike123
Reply With Quote
Old Dec 11, 2006, 02:54 PM
all thumbs
Upstate NY, USA
Joined Dec 2005
201 Posts
You could try a planet with less gravity.
Padesatka is offline Find More Posts by Padesatka
Reply With Quote
Old Dec 11, 2006, 03:19 PM
AMA 506547
punkindrublik's Avatar
United States, CA, North Highlands
Joined Sep 2004
9,100 Posts
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
punkindrublik is offline Find More Posts by punkindrublik
RCG Plus Member
Old Dec 11, 2006, 03:20 PM
AMA 506547
punkindrublik's Avatar
United States, CA, North Highlands
Joined Sep 2004
9,100 Posts
Quote:
Originally Posted by Padesatka
You could try a planet with less gravity.
Ooh, I like that idea, keep me posted
punkindrublik is offline Find More Posts by punkindrublik
RCG Plus Member
Old Dec 11, 2006, 04:18 PM
Registered User
Joined Sep 2006
209 Posts
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?
skiermike123 is offline Find More Posts by skiermike123
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Extremeflight Extra vs Multiplex Acro Master Magna 3D Flying 17 Dec 10, 2008 02:11 AM
For Sale Multiplex Acro Master RTF slopenutz Aircraft - Electric - Airplanes (FS/W) 6 Jul 13, 2007 05:12 PM
Sold Multiplex Acro Master termite Aircraft - Electric - Airplanes (FS/W) 8 Mar 20, 2007 06:04 PM
Link Multiplex Acro Master $99.99 Doubletap Hot Online Deals 6 Dec 18, 2006 04:37 PM
New Multiplex 4 Engine Cargo with speed control !!!! Looks like a B-17 Joe Pierson Aircraft - Electric - Airplanes (FS/W) 0 Sep 06, 2001 02:48 AM