Aerobeez 73" Yak 54 (Green/White)

[Capt.Roll]

I received this ARF the first week of August and finally started doing some assembly on it a couple of weeks ago.

This will be a short assembly thread as I'm not going to document the routine stuff that is done on pretty much any ARF build. Since I'm setting this up as electric most of the pictures and text will deal with the minor changes during the assembly to accommodate the electric motor, ESC and flight packs.

First order of business was deciding on the motor. Since I'm flying my 71" Slick on 8S right now I want a motor that would allow me to use my current Lipo's (4000mAh and 5300mAh) but give me some flexibility to move up to 10S if I didn't like performance of the Yak on 8S.

I purchased a Motrolfly 4330-255 after several conversations with Ken at Subsonic planes. On 8S this motor will easily swing a 22X10 prop and should I make a move to 10S I'll be able to prop down to something in the 19" or 20" range. Ken recommended to keep the watts under 2700.

Going this route required that I purchase a new ESC as my Castle ICE 100 is only good for 8S or less. I bought one of the new ZTW Gecko 120HV controllers...........looks nice and seems to be very high quality. Hopefully it performs as good as it looks.

Once I received the plane the first thing I did was to determine the distance from the firewall to the front of the cowl. 6.125" is the length that puts the face of the prop hub flush with the front of the cowl. I wanted 0.5 to 0.625 for my cowl to prop clearance. Using the published dimensions for the Motrolfly 4330, a stand-off that was 3.875" would give me the prop clearance I was looking for.

I contacted Craig Morgan that owns standoffs.com (a 3DRCForums site sponsor) with what I needed. One of the requirements I wanted was to have the stand-offs internally threaded for a 8-32 bolt to a 1" depth. Craig delivered and the stand-offs are a perfect fit.



More to come..............

 

[Ohio AV8TOR]

Subd.

How long are the battery leads on the Gecko?

 

[Capt.Roll]

The motor install was pretty straight forward and it turned out perfect.



I did install the X-mount stand-off holes on the centering lines located on the front of the firewall. I thought about rotating the mount 45 degrees off the center lines, similar to a gas engine, but the lower two holes may have been very close to the floor of the motor box and I didn't want to work around that problem. Using the centering lines on the motor box did leave the lower stand-off with nothing to mount to as it was positioned over a cut out area on the lower part of the motor box.

The fix was relatively easy. I took a small piece of 1†L aluminum bracket and positioned it on the underneath side of the motor box, pushed flush against the floor and back of the backside of the firewall. It was secured with two bolts through the front of the fire wall. Thinking ahead just a bit, I have a PTE-36R for this plane if I don’t like the performance of the Motrolfly 4330 on 8S or 10S. So I went ahead and drilled the lower two mounting holes for PTE-36R and used those two holes for the securing the 1†L aluminum piece.



Once this was done I made a spacer out of scrap ply to fill the distance from the bracket to the front face of the firewall, drilled the through hole and bolted on the stand-off.



The prop/spinner gap came out where I was planning, 0.6†and the position of the motor/prop/spinner in the cowl opening looks to be dead centered.

 

[Capt.Roll]

Ray, 5.5" from ESC to end of lead, 10g silicone wire.

 

[gyro]

sub'd, looking good so far Rex. I started working on ours last night. Landing gear and rudder done so far

 

[Capt.Roll]

Was able to mount the ESC this afternoon. Up front on top side of motor box. Unlikely that heat will be an issue but it should get some direct air flow for cooling.



Did a quick AUW check using the GensAce 4S 5300's; looks like 12.5 pounds.

I'm going to see if I can get the plane to balance with the 4S 4000's; that would make the AUW just at 11 pounds. May have to move my flight pack up front. This change will have to wait till sometime later this week. Grandson is on the way over to spend the evening.

 

[Ohio AV8TOR]

Looks nice, will it be ready Wednesday morning?

 

[Capt.Roll]

Sunrise Maiden

Was able to maiden the Yak 54 this morning..........perfect weather; calm, humid and around 80 degrees.

The Yak does seem fly better than my well used 71" Slick. Precision lines are easier to hold, knife edge flight is very stable, and the few 3D maneuvers I tried (pop-tops, blender, knife edge spin) were easy to enter and looked very good. There were no surprises during the 4 flights. One thing about the 71" Slick, I never got to fly it new as I bought it at a FLI with the landing gear knocked out and the motor box damaged. I repaired the damage and flew it for about a year. Once motor box kits were available from 3DHS I purchased a kit and installed it. The Slick flies good but probably not like new.

I flew 3 different weight packs in an 8S config this morning; Glacier 4S 4000mAh, GensAce 4S 4000mAh and GensAce 4S 5300mAh. CG was pretty good but I may move the packs forward about 0.125" from their respective starting locations for the next flights as I had just a slight pull to the belly during my knife edge passes.

I have several more build pics to post along with some additional comments regarding the Yak 54 later today.

Pictures were taken by Ohio AV8TOR.............thanks Ray!

Buttoning up the canopy.



Ready to roll.



Taxi out



Airborne

 

[SnowDog]

awesome capn - congrats on the maiden...really like those colors!

 

[gyro]

Looks good Rex, great flight report!

We're almost done with ours, just need to install the rx and electronics.

Thinking we might go with a Monster scheme on this one