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Old Dec 02, 2012, 03:41 PM
Gone Gas! / Gone Crazy?
Mr Whirl's Avatar
United States, WA, Redmond
Joined Sep 2012
954 Posts
The Best of Crack Yak Tips & Tricks

I spent some time running thru the entire Crack Yak Std thread from beginning to end compiling many of the best tips & tricks. I figured before I built mine I could learn allot from others who are willing to share. If I am going to get addicted then I want to make sure I have got some super crack.

Crack Yak Build Tips & Setup Tricks
Plastic Painters Tarp
http://www.rcgroups.com/forums/showp...&postcount=155

CA or Welders glue
http://www.rcgroups.com/forums/showp...3&postcount=84
http://www.rcgroups.com/forums/showp...5&postcount=16

Control Rod Mounting
http://www.rcgroups.com/forums/showp...&postcount=264
http://www.rcgroups.com/forums/showp...&postcount=329
http://www.rcgroups.com/forums/showp...postcount=1580

Fuselage Alignment
http://www.rcgroups.com/forums/showp...postcount=1567
http://www.rcgroups.com/forums/showp...postcount=1594
http://www.rcgroups.com/forums/showp...postcount=1899

Landing Gear
http://www.rcgroups.com/forums/showp...&postcount=510
http://www.rcgroups.com/forums/showp...postcount=1523
http://www.rcgroups.com/forums/showp...postcount=1535
http://www.rcgroups.com/forums/showp...postcount=2691

Durability Enhancements
http://www.rcgroups.com/forums/showp...&postcount=838
http://www.rcgroups.com/forums/showp...postcount=1007
http://www.rcgroups.com/forums/showp...postcount=1382
http://www.rcgroups.com/forums/showp...2&postcount=18

Battery Mounting
http://www.rcgroups.com/forums/showp...postcount=1477
http://www.rcgroups.com/forums/showp...postcount=1481
http://www.rcgroups.com/forums/showp...postcount=3748
http://www.rcgroups.com/forums/showp...postcount=2901

Neutral CG
http://www.rcgroups.com/forums/showp...&postcount=162
http://www.rcgroups.com/forums/showp...&postcount=557
http://www.rcgroups.com/forums/showp...postcount=1456
http://www.rcgroups.com/forums/showp...postcount=1777
http://www.rcgroups.com/forums/showp...postcount=1779
http://www.rcgroups.com/forums/showp...postcount=3072

Motor Thrust Angle
http://www.rcgroups.com/forums/showp...postcount=2014
http://www.rcgroups.com/forums/showp...postcount=3013
http://www.rcgroups.com/forums/showp...postcount=2908
http://www.rcgroups.com/forums/showp...postcount=1358
http://www.rcgroups.com/forums/showp...postcount=3021
http://www.rcgroups.com/forums/showp...postcount=4894

Flight Trimming
http://www.rcgroups.com/forums/showp...postcount=2151

Alternate Servos
http://www.rcgroups.com/forums/showp...postcount=2097

Alternate Motors
http://www.rcgroups.com/forums/showp...postcount=1269
http://www.rcgroups.com/forums/showp...postcount=1974
http://www.rcgroups.com/forums/showp...postcount=2200

Alternate Propellers
http://www.rcgroups.com/forums/showp...postcount=1399

Alternate Prop O-Rings
http://www.rcgroups.com/forums/showp...postcount=2277
http://www.rcgroups.com/forums/showp...postcount=2278

Parallel Battery Charging
http://www.rcgroups.com/forums/showp...postcount=2678
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Last edited by Mr Whirl; Dec 03, 2012 at 12:43 AM.
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Old Dec 02, 2012, 04:11 PM
Gone Gas! / Gone Crazy?
Mr Whirl's Avatar
United States, WA, Redmond
Joined Sep 2012
954 Posts
Crack Yak S (Super) Reporting For Duty!

Setup
2x 4g Digital servos (rudder/elevator) Twisted Hobbys
1x 9g Digital servo (ailerons) Twisted Hobbys
Out-runner1450kv 24g Twisted Hobbys
Esc 12 Amp Twisted Hobbys
2s 325mah lipo battery Thunder Power
9x4.3 Tuff Prop
AUW 194g

Super Crack Enhancements
Cross drilled carbon spar & hollow carbon tube torsion bar.
Carbon tube reinforcement tail
Carbon Control horn, push rod guides, motor mount & landing Gear.
Micro Ball Links
Rubber bushing motor mounting for adjustable thrust angle.
Polystyrene angle stk motor / fuselage reinforcement
Blenderm tape reinforced hinge points

Notes
I think there is still an additional 20grams that could be shed. Lighter 19g motor / 20g Lipo / 5g hollow carbon spar / Less Welders glue usage / Etc. My custom hollow spar turned out to thick 7mm & too heavy 15g so I opted with plan B an extensively cross drilled & lightened solid carbon spar 3mm thick at 10g. The stk wood spar weighs 7g but was not nearly as torsionally stiff. I also ended up with slight alignment issue with the elevator servo, control arm & push rod guides which reduced elevator travel to 45 degree verse a potential 60. A Lesson learned for next build. We will see if all the effort and R&D makes any difference in flight performance.
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Last edited by Mr Whirl; May 08, 2014 at 08:11 PM.
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Old Dec 02, 2012, 07:35 PM
Build em lite......
Joined Apr 2012
168 Posts
Delete. Wrong group.....
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Last edited by nkhamlue; Dec 03, 2012 at 11:00 PM.
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Old Dec 02, 2012, 07:41 PM
Extremely Twisted
cwojcik's Avatar
United States, NH, Epping
Joined Oct 2005
2,641 Posts
Quote:
Originally Posted by TheEarl Of Whirl View Post
Crack Yak S (Super) Reporting For Duty!

Setup
2x 4g Digital servos (rudder/elevator) Twisted Hobbys
1x 9g Digital servo (ailerons) Twisted Hobbys
Out-runner1450kv 24g Twisted Hobbys
Esc 12 Amp Twisted Hobbys
2s 325mah lipo battery Thunder Power
9x4.3 Tuff Prop
AUW 194g

Super Crack Enhancements
Cross drilled carbon spar & hollow carbon tube torsion bar.
Carbon tube reinforcement tail
Carbon Control horn, push rod guides, motor mount & landing Gear.
Micro Ball Links
Rubber bushing motor mounting for adjustable thrust angle.
Polystyrene angle stk motor / fuselage reinforcement
Blenderm tape reinforced hinge points

Notes
I think there is still an additional 20grams that could be shed. Lighter 19g motor / 20g Lipo / 5g hollow carbon spar / Less Welders glue usage / Etc. My custom hollow spar turned out to thick 7mm & too heavy 15g so I opted with plan B an extensively cross drilled & lightened solid carbon spar 3mm thick at 10g. The stk wood spar weighs 7g but was not nearly as torsionally stiff. I also ended up with slight alignment issue with the elevator servo, control arm & push rod guides which reduced elevator travel to 45 degree verse a potential 60. A Lesson learned for next build. We will see if all the effort and R&D makes any difference in flight performance.
Great work! One thing to note: I built a very similar custom Crack Yak and did the exact same mounting method with the exact same motor, and the mounting ears on the motor broke off from vibration and a few crashes. These motors are most durable when mounted flush.
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Old Dec 02, 2012, 10:18 PM
3d Kiwi
uptime4downtime's Avatar
New Zealand
Joined Dec 2007
3,105 Posts
Quote:
Originally Posted by TheEarl Of Whirl View Post
The Best of Crack Yak Tips & Tricks
This would be great on the front page. I wonder if we can get it put there also? Great work
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RCG Plus Member
Latest blog entry: Skywing 38" Build Instructions
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Old Dec 03, 2012, 12:37 AM
Registered User
Gig Harbor, WA.
Joined Jul 2010
159 Posts
DW Rehab!

As an owner of a DW 9mm 300 Extra (1 /12 yrs old) and still looking and flying great and my Twisted Hobbies Crack Yak. (6 mo's old and flying great). I would LOVE to see some spirited, tonque in cheek competition from what I strongly believe are the two best foamy companies in the business.

Both work hard to compete and build excellent flying and high quality models
Both work to give excellent service.
Both will take more than enought time to answer any questions if you call em.
Both will deliver thier product in 3 days or less.

Can't go wrong with eather of these guys and some friendly competition will only give us better toys to play with!
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Old Dec 03, 2012, 01:05 AM
Gone Gas! / Gone Crazy?
Mr Whirl's Avatar
United States, WA, Redmond
Joined Sep 2012
954 Posts
Quote:
Originally Posted by cwojcik View Post
Great work! One thing to note: I built a very similar custom Crack Yak and did the exact same mounting method with the exact same motor, and the mounting ears on the motor broke off from vibration and a few crashes. These motors are most durable when mounted flush.
Cody thanks for your expert input. I inserted your warning into the tips & tricks post regarding thrust angle.

I highly respect your opinion on the Crack Yak & also 60 Extra EXP, i.e. vortex generators. I also wonder at times if Jewett should really be an full time aero engineer vs a financial advisor.

So if you had a properly balanced prop to mitigate vibrations & you’re aware of the increased fragility of the motor mounts, in subsequent crashes, do you believe the benefits out-weigh the risks regarding an adjustable thrust angle? Or am I just kidding myself thinking I can accurately & reliably dial in a malleable EPP plane that requires frequent flight trim anyway due to (ambient temperature related EPP expansion & contraction)? Put another way will I constantly have to adjust the thrust angle each flight session thus making myself completely bonkers?

You make the call & I will follow your sound advise...regarding the thrust angle topic...not regarding if I am completely bonkers, because I already know that I am just a little. lol
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Last edited by Mr Whirl; Dec 03, 2012 at 01:39 AM.
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Old Dec 03, 2012, 07:28 AM
Extremely Twisted
cwojcik's Avatar
United States, NH, Epping
Joined Oct 2005
2,641 Posts
Quote:
Originally Posted by TheEarl Of Whirl View Post
Cody thanks for your expert input. I inserted your warning into the tips & tricks post regarding thrust angle.

I highly respect your opinion on the Crack Yak & also 60 Extra EXP, i.e. vortex generators. I also wonder at times if Jewett should really be an full time aero engineer vs a financial advisor.

So if you had a properly balanced prop to mitigate vibrations & you’re aware of the increased fragility of the motor mounts, in subsequent crashes, do you believe the benefits out-weigh the risks regarding an adjustable thrust angle? Or am I just kidding myself thinking I can accurately & reliably dial in a malleable EPP plane that requires frequent flight trim anyway due to (ambient temperature related EPP expansion & contraction)? Put another way will I constantly have to adjust the thrust angle each flight session thus making myself completely bonkers?

You make the call & I will follow your sound advise...regarding the thrust angle topic...not regarding if I am completely bonkers, because I already know that I am just a little. lol
Thanks for the kind words!

I never wound up adjusting my thrust angle. The plane always flew fine with no right thrust or down thrust adjustments so I never bothered...these planes have so little momentum that as soon as you let off the throttle it's going to start to stall, so you may as well trim it for throttle-on flight. Also, the highly symmetrical shape of the fuselage mitigates the spiral effect of the propwash very well. However, I never really experimented with thrust angle, so if you want to try that you might find some benefit to it. I don't think the benefits outweigh the risks, but if you want to experiment, go for it! There's no reason you can't play with it for a while, then take the elastomers out when you are done.

However, keep in mind that as you play with thrust angle to fix some perceived trim change, you run the risk of harming other flying qualities as well. You're clearly experienced enough to know this, but for all of our other customers we will continue to recommend to just bolt the motor on and fly it!
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Old Dec 03, 2012, 10:08 AM
Registered User
Eganwp's Avatar
Canada, BC, Victoria
Joined Feb 2008
631 Posts
Awesome posts on this page guys! Could we please get a moderator to copy/paste the first 2 posts onto the first page? I think everyone here would agree with the idea.

PS. My first CY should arrive in the mail today! Might have to retire the LeadFeather Yak


Edit: I've reported it to the mods so hopefully they will comply.
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Old Dec 03, 2012, 10:56 AM
Slopeaholic
jimbo320's Avatar
Joined May 2011
3,682 Posts
Mods?
Can't hercdriver just update the page? He is around on here a bit. You can edit posts later.
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Old Dec 03, 2012, 11:17 AM
Gone Gas! / Gone Crazy?
Mr Whirl's Avatar
United States, WA, Redmond
Joined Sep 2012
954 Posts
Quote:
Originally Posted by Eganwp View Post
Awesome posts on this page guys! Could we please get a moderator to copy/paste the first 2 posts onto the first page? I think everyone here would agree with the idea.
I am glad that other members are finding the compiled information as useful as I have. Got to love these forums where the combined wisdom/experience of many is shared & discussed. I know that it is making me better at building, flight trimming & 3D flying.

I will let Chris make the call if he wishes to move the posts in part or full to the front page of the thread. Thanks Chris for all your efforts & support with this thread.
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Old Dec 03, 2012, 01:23 PM
Team Extreme! Team Twisted!
hercdriver7777's Avatar
Columbia SC
Joined Feb 2005
4,330 Posts
Quote:
Originally Posted by TheEarl Of Whirl View Post
The Best of Crack Yak Tips & Tricks

I spent some time running thru the entire Crack Yak Std thread from beginning to end compiling many of the best tips & tricks. I figured before I built mine I could learn allot from others who are willing to share. If I am going to get addicted then I want to make sure I have got some super crack.

Crack Yak Build Tips & Setup Tricks
Plastic Painters Tarp
http://www.rcgroups.com/forums/showp...&postcount=155

CA or Welders glue
http://www.rcgroups.com/forums/showp...3&postcount=84
http://www.rcgroups.com/forums/showp...5&postcount=16

Control Rod Mounting
http://www.rcgroups.com/forums/showp...&postcount=264
http://www.rcgroups.com/forums/showp...&postcount=329
http://www.rcgroups.com/forums/showp...postcount=1580

Fuselage Alignment
http://www.rcgroups.com/forums/showp...postcount=1567
http://www.rcgroups.com/forums/showp...postcount=1594
http://www.rcgroups.com/forums/showp...postcount=1899

Landing Gear
http://www.rcgroups.com/forums/showp...&postcount=510
http://www.rcgroups.com/forums/showp...postcount=1523
http://www.rcgroups.com/forums/showp...postcount=1535
http://www.rcgroups.com/forums/showp...postcount=2691

Durability Enhancements
http://www.rcgroups.com/forums/showp...&postcount=838
http://www.rcgroups.com/forums/showp...postcount=1007
http://www.rcgroups.com/forums/showp...postcount=1382
http://www.rcgroups.com/forums/showp...2&postcount=18

Battery Mounting
http://www.rcgroups.com/forums/showp...postcount=1477
http://www.rcgroups.com/forums/showp...postcount=1481
http://www.rcgroups.com/forums/showp...postcount=3748
http://www.rcgroups.com/forums/showp...postcount=2901

Neutral CG
http://www.rcgroups.com/forums/showp...&postcount=162
http://www.rcgroups.com/forums/showp...&postcount=557
http://www.rcgroups.com/forums/showp...postcount=1456
http://www.rcgroups.com/forums/showp...postcount=1777
http://www.rcgroups.com/forums/showp...postcount=1779
http://www.rcgroups.com/forums/showp...postcount=3072

Motor Thrust Angle
http://www.rcgroups.com/forums/showp...postcount=2014
http://www.rcgroups.com/forums/showp...postcount=3013
http://www.rcgroups.com/forums/showp...postcount=2908
http://www.rcgroups.com/forums/showp...postcount=1358
http://www.rcgroups.com/forums/showp...postcount=3021
http://www.rcgroups.com/forums/showp...postcount=4894

Flight Trimming
http://www.rcgroups.com/forums/showp...postcount=2151

Alternate Servos
http://www.rcgroups.com/forums/showp...postcount=2097

Alternate Motors
http://www.rcgroups.com/forums/showp...postcount=1269
http://www.rcgroups.com/forums/showp...postcount=1974
http://www.rcgroups.com/forums/showp...postcount=2200

Alternate Propellers
http://www.rcgroups.com/forums/showp...postcount=1399

Alternate Prop O-Rings
http://www.rcgroups.com/forums/showp...postcount=2277
http://www.rcgroups.com/forums/showp...postcount=2278

Parallel Battery Charging
http://www.rcgroups.com/forums/showp...postcount=2678
Quote:
Originally Posted by uptime4downtime View Post
This would be great on the front page. I wonder if we can get it put there also? Great work
Updated to front page! It's great posters and users like you guys that make this the best thread in the Foamy 3D section! Well done.
C
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Old Dec 03, 2012, 06:45 PM
Registered User
Eganwp's Avatar
Canada, BC, Victoria
Joined Feb 2008
631 Posts
Awesome! Thanks Chris & TheEarl!


Edit: Hey Chris I don't think the links copied properly to the front page. They don't work on my phone anyhow. You will likely have to edit his post in order to copy the full hyperlink paths.
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Last edited by Eganwp; Dec 03, 2012 at 06:53 PM.
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Old Dec 03, 2012, 07:12 PM
Addicted to 3DHS and EF
3Daddict's Avatar
ohio
Joined Oct 2010
4,649 Posts
My elevator servo is not working properly, it it always out of trim, and the servo will lock in position all the time. How do I remove the servo?
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Old Dec 03, 2012, 08:35 PM
Gone Gas! / Gone Crazy?
Mr Whirl's Avatar
United States, WA, Redmond
Joined Sep 2012
954 Posts
Quote:
Originally Posted by Eganwp View Post
Awesome! Thanks Chris & TheEarl!


Edit: Hey Chris I don't think the links copied properly to the front page. They don't work on my phone anyhow. You will likely have to edit his post in order to copy the full hyperlink paths.
Chris I PM'd you the expanded links.
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