RE: GP Extra 300S 60 Build
 

Hi Rick

I am using a DX7 and it can be programmed for dual elevator servos and dual aileron servos, but then I need to install a 6 channel receiver, I currently have a 5 channel installed, not a big deal I have a spare 7 channel receiver I could use.

Moving the servos to the back will require some mods to the fuselage but the battery can probably stay where it is, if I keep the single servo then I have to make a new battery mount, 6 of one and half a dozen of the other.

I will have a look later and see, the added torque of two servo's is the only real difference. How significant is this? Using JR 591 69oz in

RE: GP Extra 300S 60 Build
 

A more expensive approach would be to use a JR "Matchbox", or Smart Fly "Equalizer". I think Futaba makes something similar.

RE: GP Extra 300S 60 Build
 

Andrew,

This is speculative and/or an opinion and not based on any facts.

I am sure 69 oz in is plenty of power for your elevator. Especially if your flying style is smooth scale like maneuvers.

My take on the two servos versus one (within reason - also considering the size plane we are talking about) more so than torque (even though you obviously increase torque) is the reaction speed you gain from using two servo’s.

Lets say for the sake of argument, a 40 oz in servo is enough to power both elevators in all flight modes. This one servo has to accelerate and sometime reverse the direction of both elevator halves in a fraction of a second. Sure it will hold full up deflection for snap rolls etc. But, how long did it take the servo to reach full travel? If you now add two servos - the load on the transition is much less (somewhere close to half) therefore the servo reacts quicker.

Once again depends on flying style and even flight experience as to whether or not you can even feel the difference.

Another plus of two servos is redundancy, in case one fails, you still have one. Understanding this will not always help depending on where the elevator half is when the servo failed. Shorter control linkages never hurt anything either.

RE: GP Extra 300S 60 Build
 

I added the rear servo mounts before assembly but it should be fairly easy to add after too. Just two ply rails and a servo tray. By hainv ghe ply rails running instead the fuse, and a 1/8" ply tray, it all ends up flush to the fuse. Main thing is to set height right. See my thread for a photo for the layout I used.

RE: GP Extra 300S 60 Build
 

Bit the bullet and relocated the elevator servos to the rear - changed the receiver to an AR7000, Now just have to figure out how to programme the radio - manual is silent on this one.

RE: GP Extra 300S 60 Build
 

Your servos must not have the same depth as my Futaba S-3004 (1" from flange to bottom).
I had to have the servo tray mounted flush to the outside edge of the fuse vs yours which is 1/8" indented because of the rails running on the inside.

(I assume you have both mounted and do not have them hitting)

RE: GP Extra 300S 60 Build
 

Both servo's are mounted, about a 2mm (1/16") gap.

Need to still finish off around them for covering.

Programmed the radio - all systems go.

RE: GP Extra 300S 60 Build
 

another thread to watch and take note of. man rcu is full of these 60 builds of the extra 300. what engines are you guys you guys using for the extra 60 size?

RE: GP Extra 300S 60 Build
 

I have installed a Saito 125a in mine.

RE: GP Extra 300S 60 Build
 

OK. So that is 620 g engine versus my ST-90 which is 589 g. Your stock muffler is 80 g and I would "guess" mine is around 100g.
I should not have a problem if your balances fine.

RE: GP Extra 300S 60 Build
 

I do not think you will have a problem, with the rear mounted servos your battery pack will be closer to the CG than mine which is closer to the TE of the wing bay.

Moving the battery an inch either way makes a big difference. I do not think you will have to add lead at all.

RE: GP Extra 300S 60 Build
 

Part of me was hoping for tail heavy because then I would have to buy an aluminum spinner instead of plastic :D
I just could not justify the extra $30.....but.....

I am surprised the battery swings things that much. I can spot the battery anywhere, regardless of the rear-mounted servos as I had planned for extension wires anyway for ailerons and rear servos.

RE: GP Extra 300S 60 Build
 

Wow, 2 weeks since the last post.

Started covering the wings. Using Ultracoat. Decided to glue the control surfaces in before covering and then seal the hinge gap before puting the base coat on. (Photo's 1-2)
Photo 3 is the covered Aileron.
Photo 4-5 the completed wing minus the trim.
Photo 6-7 Starting to put the trim detail on.

Edit - Ok the photo order seemed to have got scrambled but hopefully you get the idea!

RE: GP Extra 300S 60 Build
 

Here is mine. I posted it on the Carl Goldberg thread by mistake

RE: GP Extra 300S 60 Build
 

Hi guys, just in the middle of building the wing on my extra. Has anyone looked at an electric setup for it. What do you think it would require battery wise?

RE: GP Extra 300S 60 Build
 

dale691 - Don't know of anyone at our club with electric in a plane this size so not much help, sorry.

colmo-RCU - Great colour scheme. I assume that the pattern is printed and you didn't cut out each item separately:)

Some more photo's. Left Wing Bottom now completed. 4" blue stripes over the white basecoat at 4" spacing, both orocover.

Popped any bubbles with a sharpened needle, pretty chuffed with how it turned out.

RE: GP Extra 300S 60 Build
 

Andrew,

Looking good.

RE: GP Extra 300S 60 Build
 

At the point, now that the bottom of the wing is finished to cut out the trim pieces for the top wing surface.

I have only cut trim in straight lines before so curved sections are new to me. I intended to mark out full size on tracing paper over the top of the plans and then transfer to a cardboard template and then cut out.

Are there any other ways of doing this?

Proposed trim scheme below:

RE: GP Extra 300S 60 Build
 

For a scheme as yours the only way I have made a pattern is the way you are planning to. I would be putting the yellow on first with it being about 1/4 wider than finish so the blue and red could overlap. Is that what you were planning to do?

RE: GP Extra 300S 60 Build
 

Exactly. Blue ultracoat shows through yellow, so I had planned to place the yellow first and the others over that.

I have marked out on tracing paper and will ask my wife to check visually before cutting the covering

RE: GP Extra 300S 60 Build
 

Marked out and cut the templates from 1mm craft card. Folded the ultracoat in half (to make sure I got a left and a right piece:D) and cut out.

Laid it out first then tacked down the red outside edge, sliped the yellow underneath, lined it all up and stuck it down together, then laid the blue over the top of the yellow.

Did the other side too.

Next to do a final dress up of the wing saddle with micro balloons.

RE: GP Extra 300S 60 Build
 

No, Andrew, its all Monokote. Cream background with metallic red and dove gray rhombusses (did I spell it right?). the optical effect is pretty cool, IMO. The plane was actually too heavy with the YS 120 and flew very erratically because I live at 8300 ft in Bogota, so I changed to a Magnum 90 and ohh what a difference. Hehe, it is actually the only time I have downsized to upgrade performance on a plane. Sadly I don't have any more pics and the plane died in a too low spin about a year ago.

I love all those curves and colors one on top of the other, but am actually scared of all the bubbles and wrinkles. Good job there


Mariano

RE: GP Extra 300S 60 Build
 

The bubbles and wrinkles are easy to manage with ultracoat. Even if a bubble forms over an open area it is easy to pop with a needle through the top layer only and then to seal down. Ultracoat is very forgiving.

Sorry about your plane - but it gives you the opening to build another:eek:

RE: GP Extra 300S 60 Build
 

Hi All. I finished my wing today and ive got good help from this thread. Thanks to all.

RE: GP Extra 300S 60 Build
 

Wow very nice!