Nitroplanes 85" Yak

[Z06kal]

I was looking at the thread regarding this plane. It appears the design has changed for the worse. Does anyone have a recent version to describe if any of these problems have been fixed? IE two peice main gear, more weight, etc etc. ??

[ditchit]

It's 82" actually. I didn't have an original but for the money the current version is OK. The two part U/C is just a bad idea. It buckles under the weight of a 50cc engine or 10S electric setup on landing. If you replace it with a carbon U/C there's a good chance you will rip out the mounting plate so re-inforce with more glue and ply in this area. Servos have been moved out of the stabs to the side of the fuselage for the elevator. Not as pleasing to the eye obviously. The poorest aspect of the model are the wing tubes and phenolic tubes. They are truly awful but are adequate if treated with care. They are nothing more than cardboard tube so deform or tear very easily. The hardware is OK but heavy. Closed loop system is poor and some of the threads on the clevises are not manufactured well. Test each thoroughly before use. Same with some of the blind nuts. A couple of pre-installed blind nuts for the stab attachment were no good so I had to remove covering from the tail area to replace them.

Ultimately there were several issues during my build which were annoying but the price is a third of an Extreme Flight Yak so I'm not unhappy with what I got. Pictures of mine here. I initially ran it on a big Turnigy motor that siezed after 5 flights. Subsequent Hacker A60-18L on 12S and 22x12 was excellent but I still need to save some weight for unlimited 3D. I'm using 53g digital servos all round so will change aileron servos to something lighter and may come down to 10S and bigger prop. I'll also try a A80-10 on 12S when, if ever, it becomes available.

http://fdmac.hampshire.org.uk/NewSite/models_30percentYak54.php

Ha...just went to the NitroPlanes page for the Yak 2.2m and they've put in a link to my YouTube video. Damn cheek! Entirely legal obviously.

[Z06kal]

ditchit how does it fly? 3D, hover etc? Wing rock in high alpha etc?

[ditchit]

I really haven't flown it long enough to be able to fly it full 3D. My setup A60-18L, 12S, 22x12 was not enough to pull out of hover as well as I wanted so I decided to wait for the A80-10 before I tried again. A80 will not arrive for another 4-6 weeks minimum, so my focus will be to try to reduce weight to increase the watts/pound. Reducing cells and increasing prop being where I will try to achieve that first. Will let you know how I get on.

[MarkF]

I think you need to move up to a 24 X 12 or 25 X 12.5 prop. Thats what most are running with that motor.
Mark

[drstillpatient]

I really haven't flown it long enough to be able to fly it full 3D. My setup A60-18L, 12S, 22x12 was not enough to pull out of hover as well as I wanted so I decided to wait for the A80-10 before I tried again. A80 will not arrive for another 4-6 weeks minimum, so my focus will be to try to reduce weight to increase the watts/pound. Reducing cells and increasing prop being where I will try to achieve that first. Will let you know how I get on.


What MarkF said...you'll get the 3D power on your A60-18L with a 24x12 prop, or atleast a 24x10...

[ditchit]

My mistake actually. Prop is a 24 x 12 Bambula but at between 17-18 pounds I'm not getting the 200+ watts per pound (from memory). I'm going to re-assemble everything and try to make some weight savings

[ditchit]

Re-maiden on Hacker A80-10, MasterSpin 170 ESC and Zippy 12S5000. Two flights later I crashed hitting LVC on the ESC in a hover. My fault for trying a lower capacity set of packs. No problem...had a year on this airframe and was getting a bit beat up. I got another to put together. Lesson learnt.

http://www.youtube.com/watch?v=4iZ13h9IKVU

[ditchit]

For anyone interested in seeing an expensive crash...and I think that's most...

The lesson is to always thoroughly statically test the power system even with the different combination of packs to be used at the field. I had two successful flights on Zippy-H 12S5000 and on third flight flew on Zippy-R 12S4800. I had tested in a short burst on the ground before take off but if I had tested for more than 10 seconds at full throttle I would have spotted the problem. I hit 3V per cell in the middle of a nice hover straight after take off. Another 10 feet I would have got away with it. :rolleyes:

http://www.youtube.com/watch?v=3SrPKb1ak1w

Fortunatley no damage to any component of the power system...except the prop.

[Lynxman]

That's too bad.

[feathermerchant]

I cannot vie wthe video now but your post implies you were using hard cutoff. Is that right?

[ditchit]

Yes, not the best idea when you're hovering so I've changed that for the next Yak.