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Gyroo II 'the pusher version'

Richard Harris

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My ongoing Nellie build needs a few things testing before it progresses any further. 

To do this I decided to pause it and scribble up Gyroo II as a kind of adjustable test bed.

This will be a pusher version of the  Gyroo utilising the same blades, servos tail parts etc

In the same way as the tractor version the main components will be easily replaceable. I still have wood left over from Gyroo so I dont have to put my hand in my pocket again for build materials.

The drawings are virtually complete and  I have tried to keep it as Gyrooish as possible.

 Templates have been printed so I can progress with cutting the bits out whilst I await the arrival of a higher KV motor.


More in the next few days.









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All parts have now been cut out, just need to give them the once over with the sanding block and I will dry fit things together. Out of interest, there are 5 more parts to cut out than the Gyroo, these are mostly the motor mount bracket items. The UC is slightly narrower than the original with two vertical legs to attach wheel spats to. I have started making these from oddments of balsa box bits.




I have also purchased a Coolwind Razer head, 1mm Gyroo tri plates and the blade rienforcer FG sheet. All came the next day!

Motor and ESC arrived this morning (another FB bargain). Head servos will again be the Corona DS-239MG as they have performed faultlessly on the prototype Gyroo.




I will crack on with the U/C assembly first as this slots into the main fuselage body.


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The UC assembly has be made up this morning along with the motor mount.


Keeping inline with Gyroo this one will also  a tail dragged,  something I've never tried before on a pusher so it's position is guess work and subject to be scrapped if it doesn't work out.

In the same way as Gyroo the piano wire leg is sandwiched between 3 formers. This unit will slot into the fuselage on final assembly through the battery appature.




The lugs are for the battery mount to lock into.




The motor mount  is made from 5 off 3.2mm lite ply formers with 6.5 mm balsa spacers, I used the spruce mast to size the gap. This will give me the ability to slide it up and down to align the thrustline with the vertical CG.

The mast will be vertical on this one as its easier to keep the thrustline horizontal.




The complete mount, motor will be offset to the right (looking from behind) but its final position is unknown at the moment. 




It's a good tight fit on the mast so should only require a tack of glue to secure.




I will make a start on the fuselage tomorrow.

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As with the Gyroo the main fuselage is laminated up, a 6.5mm balsa core sheeted each side with 3mm lite ply.

The outers are made from two pieces each side so as to create a slot for the horizontal battery mount, I used scraps of wood to size the slot.




This is repeated on the other side with the exception of the rear 6.5mm balsa inner. This is positioned so the spruce mast is a good fit, again sized with the mast itself.




All is drying as I type, once it's cured I will give it a sand and dry fit the U/C assembly and battery floor.

While waiting I will crack on with the tail end.

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I've made up the tail feathers and their mount, there is no change to these.




Ive also dry fitted the fuselage together without any issues, the battery floor slides into its slot then clicks into position on the location tabs, there's one each side.










Next job to tick off the ever decreasing  list is the mast, head  and servo mounting. 

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The mast is complete though its length may need to be altered, the 6.5mm spruce has been faced each side at the top to match the hole in the head mount.




I have also sanded down the spats and soldered some brass mounts to the vertical legs on the UC wire, a bit rough  but nothing a bit of paint won't hide! Their position is held via a couple of 3mm lite ply pieces.







I've made an error whilst assembling the motor mount so I will remake this over the next few days.

I've still got the servos to mount but couldn't resist slotting it together.








Once the servos are installed its time to find out where my CG location  and then adjust mast, boom lengths to suit, time to think about I  covering then.

Not bad for 6 evenings work.

Edited by Richard Harris
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You've shamed me into covering Paul which has probably taken longer than to build it!




Ive left the mast bare for now as it may need it's length altering dependent on how the CG turns out. I've also made another motor mount which is lower, this may need to be altered further.

I will install the rudder servo and its connections next then on to the blades. 

I shape these outside on a belt sander so it may be a few days before the weather plays ball. 


Edited by Richard Harris
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5 hours ago, Max Z said:

Nice build Rich! As always, I admire the aesthetics of your colour scheme, very elegant. 



Cheers Max 


2 hours ago, Preben Soegaard said:

I like your elegant colour scheme. Really nice. The battery pack colour looks a little off in my opinion 😉
Thank you for sharing your interesting build.


If it were up to my daughters the battery would have matched perfectly with the colour scheme they proposed!

Luckily Dad won that battle.........this time!

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Had a break in the weather this morning so moved my modified belt sander outside to profile my blade blanks.

I've stretched this sander long enough to sand my standard blades in one length and had some abrasive belts made up to suit, seems to work quite well.




As I always do I start by removing wedges, then roughly sand the aerfoil.







These are then finished by using 3D printed profiling blocks differing in size with sandpaper attached.





The profile is modified slightly to that of the Gyroo, I'm hoping they will  require no negative shim. The blade sizes are identical but these use a larger spruce LE, there's valid reasoning for this.


I've gone with the cnc routed fibreglass rienforcers from coolwind for this set, makes life easier.







Each blade has been weighed, one was slightly lighter so Ive added pva to match the rest (no2 blade), they all weigh 45g now. Mount holes have been drilled so it's just a quick balance up then get on with their covering. 

Then it's on to final assembly, motor positioning and thurst alignment setting up.

If all goes well there looks like there's  high pressure heading this way so I may push for a weekend maiden.




Edited by Richard Harris
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Managed to get the Gyroo II flight ready, as the weather was calm today I went up to the patch and maidened it.

It made several small trimmingbhops before committing to one circuit to get a feel of things. A little bit of lead was added to the nose as a temporary gesture, I will cut the battery appature out a bit to move the battery forwards so it can be removed.

It's probably the most hassle free maiden I've ever had, couple of clicks of left trim and five of down and it was almost flying hands free.

The tail dragged configuration works fine despite the higher thurst line and there seems to be plenty of power though not to the same extent as the tractor.

I've only had one full flight but I'd say it's even easier than the Gyroo to fly, possibly something to do with the smaller prop.

A few snaps before it took to the air and some of it flight ( these are just snap shots from the video)

I will make the necessary amendments and try again on a brighter day, I'm pretty chuffed.

Video will follow.




















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On 15/12/2023 at 16:37, Outrunner said:

Well done Richard, your pusher Gyroo looks really nice 👍


RCM&E plan next year?



Thank you.

It would be wrong for me not to share the Gyroo II as it flies so well, so yes I will submit it.


Next thing to do is redesign and make a new motor mount now I know the thrust offset position, then get out again and test.

Just a case of tidying the drawings up and passing them on to the ready and waiting 'nuts' to confirm fits and CG position etc.

I'm sure they will post their efforts as they get going.




Edited by Richard Harris
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  • 2 weeks later...


I have also started this build with the kind permission Of Richard Harris.

Here are some of my build pictures.




So here you can see the Tail plane and Fin along with the center core of the body. And the rest of the parts to be cut out of lite ply.




I find that the Liteply parts can easily be cut out with a Box Knife.




As Above.




So thats the construction of the Body.



This is a dry fit of the Battery tray and under carriage parts, I now need a wire bender to form the under carriage legs before I can assemble the rest of it.


Cheers Steve.



Edited by Stephen Jones
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