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Old Feb 19, 2015, 08:40 AM
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Poffertjesporem's Avatar
The Netherlands, NB, Sint-Michielsgestel
Joined Nov 2014
120 Posts
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Extreme control surface deflection benefits?

Hi all,

During my PA Addiction x build, i made my elevator control rod to short, becouse i did not gleu in the control horn, and it moved during fitting.

I ordered some CF tube to fix my error.

I have seen pic on the forum of 3d planes with 90 degrees elevator deflection, and this made me wondering.

Wy the big deflection?, the boundery layer wil seperate with those angles. Is it the increase of drag that is genatated the reason for this extreme deflection?

Should i make my addy elevator deflection 90 degrees?

I dont use the lowrates on my tx, so i am thinking of setting up an extreme rate, maximizing al control surfaces, as i still have room to play (now using recommended trows acc manual)

Any insight would be highly appriciated.

Best regards Boris.
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Old Feb 19, 2015, 08:54 AM
AKA Amraam
Newcastle, England
Joined Feb 2007
668 Posts
Quote:
Originally Posted by Poffertjesporem View Post
Hi all,

During my PA Addiction x build, i made my elevator control rod to short, becouse i did not gleu in the control horn, and it moved during fitting.

I ordered some CF tube to fix my error.

I have seen pic on the forum of 3d planes with 90 degrees elevator deflection, and this made me wondering.

Wy the big deflection?, the boundery layer wil seperate with those angles. Is it the increase of drag that is genatated the reason for this extreme deflection?

Should i make my addy elevator deflection 90 degrees?

I dont use the lowrates on my tx, so i am thinking of setting up an extreme rate, maximizing al control surfaces, as i still have room to play (now using recommended trows acc manual)

Any insight would be highly appriciated.

Best regards Boris.
I think typically those levels of deflections are used post stall anyway.
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Old Feb 19, 2015, 09:31 AM
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ronaldopn's Avatar
Brazil, RJ, Rio de Janeiro
Joined Oct 2012
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I would be interesting to see the effect of 90 degrees on an elevator
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Old Feb 19, 2015, 10:26 AM
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theKM's Avatar
central PA.
Joined Sep 2004
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some maneuvers can use the drag to slow the model while making use of the extra deflection (knife edge spins, parachutes, etc), outside of that there's generally decreasing returns for the rest of the envelope. Not uncommon though, the "just about 90 degrees" elevator throw crop up all the time on the Extreme Flight threads as they double bevel enough to do it pretty easily without a large hinge gap.

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Old Feb 19, 2015, 10:29 AM
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theKM's Avatar
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also worth noting is that the higher the throw, it is reducing the servo holding power... also part of the reason why ExtremeFlight recommend a more beefed up servo for elevator. If you go from 45 degrees throw to 90, you may start experiencing blowback, etc.
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Old Feb 19, 2015, 01:02 PM
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The Netherlands, NB, Sint-Michielsgestel
Joined Nov 2014
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Thanks fore the responce guy's.

I'm running 5085mg hitec servo's (http://www3.towerhobbies.com/cgi-bin...P?I=LXSDB1&P=8), at 5,6V, are these up to the Job?

And is there a way to calculate/ test this?, don't want the elevator to fail during flight lol.
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Old Feb 19, 2015, 01:50 PM
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theKM's Avatar
central PA.
Joined Sep 2004
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Quote:
Originally Posted by Poffertjesporem View Post
Thanks fore the responce guy's.

I'm running 5085mg hitec servo's (http://www3.towerhobbies.com/cgi-bin...P?I=LXSDB1&P=8), at 5,6V, are these up to the Job?

And is there a way to calculate/ test this?, don't want the elevator to fail during flight lol.
if you can get a BEC to 6v it would be better. my guess is it will be fine, it's not a super speedy plane as it is.
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Old Feb 19, 2015, 04:44 PM
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Thanks KM!, i'm going to try it out, and post the results here.
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Old Feb 25, 2015, 06:13 PM
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The Netherlands, NB, Sint-Michielsgestel
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Flew the addy today with the larger elevator throws.

I had to make room fore the cf elevator tube, sleeved the cf control rod, added hotgleu around the servo, extended the servo arm to 2.8cm and painted the sanded balsa with thin ca.

I can't get the trows to 90 degrees because the control rod hits the horizontal stabilizer going up, and fuse structure going down.

First i need to increas my skill level lol, this mod really speeds things up.

Im not jet happy with the geometry of the control cod, i might change the elevator control horn and/or change the servo location.
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Old Feb 25, 2015, 09:52 PM
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Joined Jan 2005
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I haven't found that control throws much over 50 degrees is of much use.

I owned an Extreme Flight MXS. The manual mentioned you could set the plane up for 60 degrees or more of travel, so I tried that on my highest rate. I found that at least for the MXS 48, there was no benefit to going past 50 degrees. I at least expected a maneuver like the elevator to improve, I also expected flatter flat spins, but neither maneuver improved. If anything the excessive elevator travel made the maneuvers somewhat unstable.

Maybe on another plane the results might be different. Although I like most Extreme Flight planes, the MXS 48 is not a plane I would recommend to anyone for 3D flying.
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Old Feb 26, 2015, 05:45 AM
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I suspect that elevator flex makes it unstable, i might ad some cf to beef mine up.
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Old Feb 26, 2015, 07:04 AM
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C_Watkins's Avatar
United States, GA, Atlanta
Joined Jul 2011
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For what the Addy-X seems to be designed to do, that extreme elevator throw may not help you a lot anyhow.
This seemed more like a low-and-slow floater and hovering trainer, to me.
Fun to fly, no doubt. But more traditional and/or profile-style 3D and not really made for XA nor precision.

Quote:
Originally Posted by malcolmm View Post
I haven't found that control throws much over 50 degrees is of much use.

I owned an Extreme Flight MXS. The manual mentioned you could set the plane up for 60 degrees or more of travel, so I tried that on my highest rate. I found that at least for the MXS 48, there was no benefit to going past 50 degrees. I at least expected a maneuver like the elevator to improve, I also expected flatter flat spins, but neither maneuver improved. If anything the excessive elevator travel made the maneuvers somewhat unstable.

Maybe on another plane the results might be different. Although I like most Extreme Flight planes, the MXS 48 is not a plane I would recommend to anyone for 3D flying.
I like the big elevator throws for tumbles, KE spins and crankshafts but run my midrate 45-50 degree elevator for everything else.
For harriering around, if you're one that likes to peg the elevator then yeah the insane elevator throw isn't going to be very helpful.

I haven't owned the little 48" MXS, but I do love its bigger brothers.As with any plane though, a lot of it comes down to your desires, skills and flying style.
Lots of people have an absolute blast with the 48" MXS. I've seen 'em
Jase Dussia seems to be having fun with his.
Extreme Flight 48" MXS EXP Snow Huckin' (9 min 40 sec)
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Last edited by C_Watkins; Feb 26, 2015 at 07:12 AM.
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Old Feb 26, 2015, 11:21 AM
Julian T
Fleet, UK
Joined Jun 2005
577 Posts
Unfortunately I can't fly like that and it's fair to say Jase could fly a brick better than I can fly a plane! But I can say the MXS is my favourite of the 48" range for hard and fast 3D. I have had two. It loses out to the Edge in low and slow and the Extra in flying clean lines but in explosive manoeuvres it is extremely good imo. So for full on high energy 3D I would highly recommend it fwiw!

Back on topic, I have found extreme throws to be very useful for the hard tumbles, etc. that going from high speed 'normal' flight to near instant stall condition require but for slower 3D such as harrier, etc. I find they are unnecessary and even counter productive. YMMV
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Old Mar 02, 2015, 07:11 AM
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The Netherlands, NB, Sint-Michielsgestel
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Great vid!

Beefed up my elevator today.

Glued in a 3 mm cf tube using 30 min epoxy, next step is making a custom control rod. I did not like the long servo arm, as it makes the forces on the servo bigger and enlarges the hinge play.

To be contineud....
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Old Mar 02, 2015, 08:48 AM
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United States, IL, Glenwood
Joined Nov 2013
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More then 50 deg definitely makes it knife edge spin and crankshaft faster and more violently And if you couple the extreme elevator travel with a spoileron to elevator mix it will drop strait down.
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