Wing area on 24% CA Extra  
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All Forums >> RC Airplanes >> Giant Scale Aircraft - 3D & Aerobatic >> Wing area on 24% CA Extra
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Wing area on 24% CA Extra - 9/3/2003 12:50:51 AM   
Scoubidou



Posts: 1569
Joined: 7/7/2003
From: Boisbriand, QC, CANADA
Status: offline 		Hi Ragz
Sorry for the confusion,
I am going to use the mk bellcrank with one servo in the fuse near the rudder's servo, not digital. There are too expensive for my needs.

Based on all 24% owners , the rudder+elevator servos must be installed near the wing tube instead to the tail position. Put them behing the firewall, if requires!!
Scou

(in reply to Scoubidou)
       Post #: 26

Wing area on 24% CA Extra - 9/3/2003 1:10:19 AM   
Tipover


 

Posts: 433
Joined: 6/24/2002
From: Outoftown, WI, USA
Status: offline 		[QUOTE]Originally posted by Scoubidou
I love that huge RUDDER!!

You can save 3oz by replacing the main landing gear and 1 oz, if you put a micro servo for throttle and if you search more, you will remove 2 or 3 oz to get 8oz (1/2lbs) weight saving, where that plane begins to glide!!


I haven't monted yet, but what advantage is to install that tube rearward?? It will be more tail heavy??
Scou [/QUOTE]
I think I could shave off 8oz if I really try. Its the weight distribution thats the issue.

The wings center of lift is a fixed point for any given airfoil. By moving the wing tube aft on the fuselage, you'll end up with a balanced plane around the wings center of lift. A planes Center of gravity is the movable range around the wings center of lift where the plane will still fly with a certain amount of inherent stability. Remember the little balsa gliders with the sliding wings?? slide the wing forward, or aft, to get the flattest longest glide, no weight added or removed

Kevin

(in reply to Scoubidou)
       Post #: 27

Wing area on 24% CA Extra - 9/3/2003 1:43:13 AM   
Tipover


 

Posts: 433
Joined: 6/24/2002
From: Outoftown, WI, USA
Status: offline 		Ragz,
I understand your dilemma, its hard to save weight when you can't take it off.

I wonder if a bellcrank will have a significant effect on the overall cg issue. You still have the linkages and bellcrank assembly back there. Plus the weight of the pushrod going back will about equal a servo extention. Seems like your only moving the weight of one servo forward?? How about two mini digitals in the back?

Kevin

< Message edited by Tipover -- Sep 2 2003 8:48PM >

(in reply to Scoubidou)
       Post #: 28

Flying wires required? - 9/3/2003 9:00:46 PM   
Scoubidou



Posts: 1569
Joined: 7/7/2003
From: Boisbriand, QC, CANADA
Status: offline 		Hello Tipover,
Are you going to put the flying wires on the tail? Your pic does'nt show it?? Did you reinforce the stab and fuse to avoid those wires?

And about you Ragz, Do you recommend me to install them?

Scou

(in reply to Scoubidou)
       Post #: 29

flying wires - 9/3/2003 9:41:45 PM   
Tipover


 

Posts: 433
Joined: 6/24/2002
From: Outoftown, WI, USA
Status: offline 		No flying wires for me. A balsa sheeted foam tail is very stiff on this size plane. I have a stick built tail on my 25% aeroworks Edge. No wires on that either. I think CA recommends the wires above 27% size.

My extra lost 3 oz's last night just changing wheels. The Kavan 3" wheels weigh .89 oz each. You can get them at Hobby Lobby. Also changed the tail wheel to a foam park flyer wheel.

Kevin

(in reply to Scoubidou)
       Post #: 30

Wing area on 24% CA Extra - 9/3/2003 10:29:26 PM   
DENNIS C



Posts: 2965
Joined: 7/8/2002
From: frisco, TX, USA
Status: offline 		Hey guys if you are interested in a C/F gear. there is a member here on RCU. by the user name of TT2 i bought my gear from him for 30.00 shipped. i think he has a few left. they are not perfect but i think they will hold just fine. plus they are a little taller then the stock one

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       Post #: 31

Wing area on 24% CA Extra - 9/3/2003 11:15:56 PM   
Ragz



Posts: 1706
Joined: 12/6/2001
From: Nagpur, INDIA
Status: offline 		i dont think 2 small digis will help too much either. I am just gonna fly this one like it is...Ihave another kit of the 24% lying with me..and I will make mods in that. Other than making holes in the fuse and tail, I will think about keep the engine box the same size as in stock and increase the fuse from the front instead. This may look unscale, but the plane may balance better.

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Anurag

(in reply to Scoubidou)
       Post #: 32

Wing area on 24% CA Extra - 9/3/2003 11:45:07 PM   
Scoubidou



Posts: 1569
Joined: 7/7/2003
From: Boisbriand, QC, CANADA
Status: offline 		Hi Ragz!
1)Did you see a weakness or cracks in your tail after your flights without the flying wires?

2)I am now considering to put only one servo in the tail for the elevator instead of bellcrank. Why Ragz and Tipover have put 2 servos in the tail? Is it to much area to move for one servo?

3) Thanks to Tipover for the Kavan wheels they're really light!!
Scou.

(in reply to Scoubidou)
       Post #: 33

Wing area on 24% CA Extra - 9/4/2003 11:02:07 AM   
Ragz



Posts: 1706
Joined: 12/6/2001
From: Nagpur, INDIA
Status: offline 		Scou, I notice no cracks on the tail. Its been built pretty strong. The elevator CAN be made to work with a single servo...but then, it will only work. I dont expect it to withstand violent 3d manuevers. With my setup, this plane can do stunning walls. The elevator surfaces are quite large and travel a fair bit. I did not want to compromise elevator authority. If you want to use a single elevator servo, do you intend to JOIN the 2 halves with metal wire? I dont know how good that idea is...If I had to redo it, I would eother use a bellcrank or install pull pull on the elevator also...and place the elevator servos right up ahead on either side of the rudder servo. This is just my opinion however.

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Anurag

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       Post #: 34

Wing area on 24% CA Extra - 9/4/2003 5:30:01 PM   
Scoubidou



Posts: 1569
Joined: 7/7/2003
From: Boisbriand, QC, CANADA
Status: offline 		Hi Ragz
So based on your experience, I will not install the tail wires and save a few oz...
I was thinking to use a U wire to join the 2 halves and one servo in the fuse but probably the elevator area is to big for that setup. Probably the MKbellcrank or pull-pull system would work better for aerobatic. The problem with the bellcrank is how can you have access to it after the fuse is covered?

I want to use that plane to compete in IMAC sporstman class next year. I won the first position last month with my little GP super sporster 40 in basic class and i am ready for the second step!

About your idea to modify the fuse, it will be easier to trade your engine with a small gasser like MVVS1.6, Zenoah G26 or 3W24. These gas engines are heavier than your Saito without loosing to much power. The Saito180 is a great engine and very light at 880g but not suitable for the 24%CA Extra CG position. That's my personal opinion and don't get angry!! That plane seems to be designed for a 3lbs gas engine on his nose because the engine box is already there.

There are a lot of good used engines in RCU to sale or better , you can trade it!! Anyway good luck!!
Scou.

(in reply to Scoubidou)
       Post #: 35

WING INICDENCE ???? - 9/5/2003 1:44:57 AM   
DENNIS C



Posts: 2965
Joined: 7/8/2002
From: frisco, TX, USA
Status: offline 		hey guys how are you setting your inicdence on the 24% 300.

are you leveling out the fuse then setting your inicdence?

Im in the middle of doing that now and im having a problem.

if i level the fuse then the stab inicdence is at -1 deg. it should be at zero correct me if im wrong.

i can set the inicdence at 0 on the wing and the stab but is that the correct way. then the fuse will not be level.

need some help here guys

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       Post #: 36

Wing area on 24% CA Extra - 9/5/2003 2:55:28 AM   
Tipover


 

Posts: 433
Joined: 6/24/2002
From: Outoftown, WI, USA
Status: offline 		I leveled the wing to the fuse, same with motor. If adjusting the stab is a pain, I'd just leave it. With about half the total tail area being elevator(movable), you won't need much trim to straighten things out. Trim equals drag... basically a non issue on a slow flying aerobatic plane. More important is getting the stab and wings parallel, and at 90* to the fuse. You may have to fine tune the engine thrust after you fly it anyway. JMO.

Kevin

(in reply to Scoubidou)
       Post #: 37

Wing area on 24% CA Extra - 9/5/2003 3:27:32 AM   
DENNIS C



Posts: 2965
Joined: 7/8/2002
From: frisco, TX, USA
Status: offline 		I have it figured out i just zeroed out the stab and set the wings to zero.

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       Post #: 38

Wing area on 24% CA Extra - 9/5/2003 5:45:34 AM   
Scoubidou



Posts: 1569
Joined: 7/7/2003
From: Boisbriand, QC, CANADA
Status: offline 		Hey, Welcome aboard Bodyman!

Does someone calculate the require torque for each servos? I have found a free software on RCU and here is what I have:

Maximum required torque at maximum airspeed (oz-in)
17x8 at 8200RPM=65mph

(oz-in)
ailerons: 27.1
elevator: 81.2
rudder:170.8

Maximum deflection of control surface from center (degrees)
ailerons, elev, rudder
30 30 40

Scou.
ref: http://www.rcuniverse.com/forum/tm.asp?m=134388%20sizing&pagenumber=1]

(in reply to Scoubidou)
       Post #: 39

aileron torque - 9/5/2003 6:02:46 AM   
Tipover


 

Posts: 433
Joined: 6/24/2002
From: Outoftown, WI, USA
Status: offline 		That aileron torque figure seems suspiciously low. Those are some big flappers

Kevin

(in reply to Scoubidou)
       Post #: 40

ailerons torque - 9/5/2003 6:22:18 AM   
Scoubidou



Posts: 1569
Joined: 7/7/2003
From: Boisbriand, QC, CANADA
Status: offline 		Oups!
I did a mistake, i put ''inche'' instead of cm in the program.
Here we go again with new calculations:

speed at 65mph
Maximum required torque at maximum airspeed (oz-in)
ailerons 70.2
elev 103.3
rudder 123.5

Maximum deflection of control surface from center (degrees)
ailerons:45
elevators 40
rudder 35

Wow, imagine if we want to do 3D deflection with 45degre on the rudder, we would need 200oz-in torque servo on the rudder??
I will have to forget my old standard JR537 servos

What do you think about it? Does it sound realistic numbers?

Scou

(in reply to Scoubidou)
       Post #: 41

Re: ailerons torque - 9/5/2003 6:35:27 AM   
DENNIS C



Posts: 2965
Joined: 7/8/2002
From: frisco, TX, USA
Status: offline 		[QUOTE]Originally posted by Scoubidou
Oups!
I did a mistake, i put