Capt G

My Feedback: (8)

Just got one of these and hope to test fly it today wx permitting. I took the advice of the others on this forum and reinforced the horizontal stab with 2 cf spars. Also reinforced the motor mount with 1/4 tri-stock. Left off the flimsy wheel pants but went to slightly larger, more scale looking wheels. I am using the Rim-Fire 35-30-1250. With the 11x5.5 prop it wants to climb out of my hand so I'm expecting good performance. It's a good looker though. I will post the results.

DaveH2

I'm new and still quite confused on motor ratings....so what am I missing here? I keep hearing people say that the performance is less than ideal with the recommended Rimfire 35-30-950 outrunner, and that the Yak performs much better with something like the Hacker A30-22s or E-Flite Park 480. Believe me, I'm not doubting what you guys are saying, but I'm very confused by the specs, and the results. I would LOVE to get a handle on all this. Maybe there's a good book out there somewhere?

On paper:
-The Rimfire 35-30-950kV is rated at 296W/20A constant
-The Hacker A30-22S is rated at 290W/16A constant (and is rated for a smaller diameter/pitch propeller)
-The Park 480 (910kV) is rated for 250W/20A constant, and the (1020kV) is rated for 275W/22A costant

Of these specs, it appears to me that the suggested Rimfire would be best all-around match for the Yak, with the possible excepton of the Park 480-1020kV. It (the Rimfire) has generally higher ratings and spins a good sized prop, so what gives in that everyone seems disappointed and is migrating towards motors of 'lesser' specs?

I don't care too much about level-flight speed, but I love violent maneuvers and great climbout in a small flight area. What do I need?

Thanks,
Dave

Capt G

My Feedback: (8)

Got to fly this little beauty yesterday. I'm glad I went with the RF 35-30-1250. With the 11x5.5 APC SF Prop it will climb right out of my hand! Good thing too as the flimsy wood tail skid broke off after the 2nd flight. Didn't look very good either so I added a Dubro micro tail wheel. Will see how that works today. The plane flys very nicely - some tendency to couple on knife edge but will mix that out. Very good verticals and nice straight downlines. I had to increase the low rate elevator slightly but all other suggested low and high rates seemed very good. I like this plane!

DaveH2

Cool! Which battery are you running with this combo?

Capt G

My Feedback: (8)

I'm using Thunder Power 2070 3 cell 20c packs. Ten minute flights with Castle 25 on "auto-lipo" cutoff and the batterys are only luke warm. Not enough to warm up my freezing fingers in this cooold 50 degree Vegas weather.

bzyguy01

Hey DaveH2,
To just keep things simple....Motor manufactures have specs that they put with their motors and I rarely get the same test results from their motors that they claim. I know that the specs should be exact but not everything comes off the line exactly the same. The Higher end motors such as hacker are very conservative on their specs as The Hackers are always outperforming their spesc that they claim and are very effecient in doing so. I am a test nut!.I test all of my planes,motors and servos. I have over 50+ planes and 40 are ready to fly. Many other motors don't produce the power that they claim under a load and are less effecient as they tend to pull more amps with the reccomended props.
Personally...I've had the very best luck with HACKER,Hyperion,Himax, and some Eflite's. I usually run Hacker as its been the very best for me and I also like the Hyperion results but have a harder time getting the Hyperions as Nobody in Phx stocks them. Some manufactures run funky part #s and their hard to understand going between other manufactures.

Whats with the H2? Is that what you drive?

bzyguy01

Capt G, Nice plane HUH! The Rimfire motor is fine for the plane as I see that you're happy with it but The Hacker has just that much more "POOP" and the plane will actually fly even better and smoother with an "E" prop from the "SF " prop your using with the rimfire. Don't get me wrong...Your set up is fine but beleive it or not...The other setup is even better.Thats all. Plus the plane has less tendency to "Couple" on KE and less roll during slow maneuvers. Just feels more "SOLID" and flies like a bigger bird with the Hacker and "E" prop.
Glad you took my advice on the elevator CF fix. Good choice.

DaveH2

Hi bzyguy01

Have you ever tried the Hacker A30-16M? What do you think about the possibility of using that one in the Yak versus the 22S.....would it be too much power for the airframe to take? I'm sure it could potentially increase the G-loading with the extra torque. Also, it's one ounce heavier than the 22S, but the motor could easily handle that and I'm thinking it would allow a larger capacity Lipo to be used, extending the flight times a bit. Thoughts?

The 'H2'....heh, no it's not what I drive. I typically log into all the forums I join as DaveH (as in last initial), but it was already taken in this case. I had to add the '2'.

Regards,
Dave

Capt G

My Feedback: (8)

Well guys ... 2 more flights today and I really like it with the tailwheel. BTW ... the plane + motor was $150 - delivered. Hows that Hacker priced by comparison?

bzyguy01

Within a few dollars up or down depending on the supplier. Hacker is without a doubt one of the very finest motors $$ can buy. Sean @ hacker USA is a great business operator and takes great care of his customers! He told me at a meet that he warranties all hacker stuff, Period!

bzyguy01

DaveH2, I have not tried that HackerA30-16M in this plane but I would reccomend not running it as the 22 has more than enough power and keeps the wing loading very low. Sometimes too much power is just right and sometimes it makes the plane fly terrible as wing loading weights go up.
Example: I have a Hyperion Yak54 "40E" which is a 54" electric model. My buddy bought one at the same time. My buddy used the Hyperion 14Z model motor that was reccomended and I wanted one up on him....He He....I bought the A50 Hacker and thought I would walk all over him! Right? Well as it turns out the Hyperion power to weight came out to 216Watts per pound with a 5 cell 4200Mah. Mine came out to 368 watts per pound with a 4200 6 cell. WAYYYY to much power! This setup would 3D fly a 8-9 Lb plane at a total of 1890 watts! His flew AWESOME! Mine flew like a sperm whale with wings.... Needless to say...I put the Hyperion in mine as well and now it flys much smoother and lighter and lands alot easier. By the time I got mine to CG correctly with the Hacker setup I weighed over 15 Oz's more! Almost a full pound. Funny thing was I didn't think mine would weigh that much moore as the Hacker and battery was only 3 .6 Oz's heavier. But this all in the front! So I had to add a second elevator servo and weight to CG it.

Ontariomystic

Nobody using an AXI outrunner? I have a 2808/24 that I could put in.

bzyguy01

Hey Capt G, This makes three ......Another YAK Bites the DUST!!! Today I flew my good buddys new yak. He had another one of his freinds assemble it for him. My freind is pretty green with planes so he asked me to maiden it and trim her out. The assembler took a shortcut on the elevator and Ca'd 2 CF tubes from the elevator to the fuse. I actually thought it would work, tho I was not really impressed with how the struts looked...... Well It took off nicely and only required 1 click of down elevator and 3 clicks of right aileron. Flew it for nearly 6 minutes before I started Violent menouvers and it seemed fine until I tried pulling out of a blender at terminal velocity! Full elevator and FFFLLLUUUTTTEEERRR! The strut pulled off of the left elevator stab and almost straight in it went.....Man I feel bad. It totaled the plane and took out the 40 amp ESC as well. The servos actually made it through the crash! My 2100 Lipo was totalled as well. I have such a hard time beleiving that this elevator is so darn weak. It feels somewhat sturdy to the touch and with the added strength of the strut??? SUCKS!!!

Capt G

My Feedback: (8)

Ouch! that's a shame. Mine is holding up ok so far. Maybe they will replace it for him.

bzyguy01

Hey DaveH2,
I did a watt and amp test on the Rimfire last nite and heres the results...With a 11X7 "SF" APC prop : 226 watts max and 24 Amps Max with a 3 cell Tpower 2100 lipo Thunder Power ( They claim 296 watts @ 20 amps). Much different from the claimed watt and amp readings they claim. You are forced to run this motor on a 4 cell to get the claimed results out of it as where the Hacker blows it away on a 3 cell @11.1 volts VS. 14.8 on the Rimfire to be competitive. The GP Yak 54 ready to fly with a 3 cell 2100 TP weighs 27.5 Oz's. A great 3d power to weight is 180 to 210 watts per lb. The rimfire equates to 8.22 watts per oz, 132 watts per lb....A little on the low side for good 3d performance. I did not test it with a 4 cell 2100 mah as I ran out of time but it is a much better performer with the 14.8 volts VS. 11.1 Volts.

quist

My Feedback: (198)

I took a shortcut? the kit has no bracing at all. I put the same bracing that we put on the Funtana 90 and 40. If you thought that it was to weak maybe you shouldn't have pushed it on a maiden flight.

Tony

bzyguy01

Sorry for this post guys.....I removed it as it was out of character.

bzyguy01

Quist, The shortcut I'm referring to is the tubes you added VS the flat Cf added in the elevator stabb like I did on mine as you can see earlier in this post. Not that Your lazy or anything of the sort but just easier.

quist

My Feedback: (198)

I never saw yours.

DaveH2

bzyguy,

Thanks a bunch for all the research and test results! It sure sounds like the Hacker is the way to go on this, so I suppose I'll go ahead and snag one. I'm a bit curious how the Rimfire would perform using the recommended 1250mAh/3s Lipo (lighter in weight). Your final weights are right on the money however, so I'd bet the Rimfire still wouldn't be on the same level as the Hacker even with the lighter battery.

I'm also definitely going to reinforce the horizontal stab with CF. I'm a bit concerned with the vertical stab in my kit too, as it doesn't look very strong at all....but then you haven't had any problems out of the vertical stabs on any of your Yaks yet though, have you? Or the wings? After being used to nitro planes this electric stuff seems so fragile in comparison, I'll just have to get past my paranoia. Hopefully I can get some other things done and be able to concentrate on this during the Christmas week.

Regards,
Dave

bzyguy01

Hey Dave, I wouldn't run a small 1250 Mah with this large of a motor as it might pull too much current and "Puff" the battery resulting in voltage loss during flight and .....Possibly a crash. The wing loading is still very light with a 3 cell 2100mah. No worries about that. It floats very nice with a 2100mah.
As far as the vertical...The vertical stabb doesn't get near the stress and strain as the H Stabb. I agree that alot of electrics feel very light duty and in some cases they are too light duty, but I wouldn't worry about the V stabb as It hasn't shown any failures nor after the crashes. The wings soom ok but another person in theese posts swears that they need extra support but personally I didn't change anything other than the H stabb by adding the CF. Good luck on this project and Happy Holidays.

Best Regards,
Shayne

bzyguy01

Here's the test results for the 4 cell 2100mah TP: Watts=334
Amps=27.5

Rimfire 950Kv with a 11X7 "SF" APC prop. Still not impressed!

DaveH2

Good deal, thanks again!

Btw, you mentioned that the Hacker Yak liked the APC 'E' prop best...was this an 11x7 as well?

Dave

bzyguy01

Yes it was an 11X7 "E" on the Hacker A30-22

haz

My Feedback: (17)

I just did some runs with the Rimfire 950Kv 2100 apex 15c ,11x7 apc e 19 amps 206 watts, 11x5.5 apc 190 watts 17amps, 11x4.7 apc 208 watts 19 amps and 12x3.8 apc 228 watts 22 amps. My auw on my yak is abought 30oz.