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Kraken - BUILD

grahamm

Junior Member
#41
Hey All

Has anyone experienced that the Kraken's flaps are so long and the control horns are installed at the middle tip, when you move the flaps, the whole flap actually doesnt move, it bows towards the end?

I'm using normal depron foam, not DTFB.

Any idea of how one can reinforce this?
 
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Craftydan

Hostage Taker of Quads
Moderator
Mentor
#42
Hey All

Has anyone experienced that the Kraken's flaps are so long and the control horns are installed at the middle tip, when you move the flaps, the whole flap actually doesnt move, it bows towards the end?

I'm using normal depron foam, not DTFB.

Any idea of how one can reinforce this?
that makes sense -- the paper adds quite a bit of rigidity.

Adding a layer of packing tape will help, but likely not enough. you'll probably have to put something stiff either imbedded in the middle of the foam or at the trailing edge.

CF strips are ideal, but not everyone has that on hand.

Medium sized Zip-tie plastic will likely work well, glued and taped to the trailing edge. cut off the zipper head and use the long tail.

I'd avoid bamboo skewers -- they will warp slightly with moisture -- fine for mounting pegs and such, but not so good for your flat control surfaces.
 

grahamm

Junior Member
#43
that makes sense -- the paper adds quite a bit of rigidity.

Adding a layer of packing tape will help, but likely not enough. you'll probably have to put something stiff either imbedded in the middle of the foam or at the trailing edge.

CF strips are ideal, but not everyone has that on hand.

Medium sized Zip-tie plastic will likely work well, glued and taped to the trailing edge. cut off the zipper head and use the long tail.

I'd avoid bamboo skewers -- they will warp slightly with moisture -- fine for mounting pegs and such, but not so good for your flat control surfaces.

Thank you! I'll get some flat CF strips and put those in thanks for the recommendation!
 
#46
Sits on water good, looks good.
Throttles mixed with rudder works great on the water.
Takes off and lands great.
Hard bank and yank works fine, but on soft bank and yank nose resists coming around smooth.
 
#47
I have a dumb question, my Kraken seems extremely inefficient. I used two Suppo 2217/7 1250kv motors. Should I have used different motors? I don't have the weight of my Kraken with me right now, I"m just wondering if some of you knowledgeable guys can look at the motors and tell me if those are the issue. I have changed props down to 906. I'm certain I'm using incorrect motors. But looking for some thoughts.

Edit:
Ok, some more info. I tried 10-4.7 props first, but flight time was less. I'm running two 3000mah in parallel and getting less then 10min flight time. (yes I'm also loaded with FPV gear).
 
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#48
Don't know about how the 10x4.7+Suppo2217/7 setup works with the Kraken (Although it is the suggested setup in the start of this thread), but with GWS 1047SF props they ought to draw somewhere around 20 amps each at WOT. 2x3Ah=6Amphours is the same as 360 Amp-minutes (my preferred path for estimating WOT time), so with 2 x 20A that would give you somewhere around 360 Ampminutes/40A=9 minutes at WOT, if you deplete the packs completely. Doesn't sound that far off to me.

But it of course depends on what throttle setting you are mainly flying at.

Note that with 10x4.7, 3s and 1250kV, this will never be a "sprinter", but the larger lower pitched props will, while making the plane top speed lower, have more low down "Oompfh" to get it off the ground, and probably also better efficiency.

Also do note that the glassfibre APC 10x4.7SF's will have both a bit more pulling power and better efficiency than GWS or similar cheaper all plastic SF versions.....but they will also draw a little bit more current.
 
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#49
Thank you DKchris. I was just comparing my setup to what Josh said when he said with a 5000mah battery he could get 30 minute run times. (it could have been 6000mah, I'll have to rewatch the episode) I'll do some more testing. I did notice that the recommended motors are Suppos but I don't see Josh using them on any of the Krakens so I thought maybe the Suppo was an incorrect motor to use. Thanks again, I'll keep trying. I'll also check out the glassfibre APC's.
 
#50
Your flight style (which among other things is usually also quite influenced by CG placement, AUW, motor angles etc.) and the weather conditions can make a huge difference on what kind of run times you get. 30 min run times could never be WOT with the mentioned components.
But if the plane is carefully trimmed to be able to "putter" around at perhaps something like half throttle more or less hands off aiming for high efficiency, flight times in that order should not be impossible. AUW of course also makes a huge difference

A local friend of mine actually has a rather light (all depron and Tape and just a 3.3Ahr pack, but similar motors/props) FPV Kraken, which he has basically first trimmed to fly as optimally as he can as a glider, and then trimmed the motor angles to stay in level flight regardless of the throttle setting. In calm weather he fairly easily gets 15-20min flight times, while he does put in quite a few pure gliding segments - he is a 1:1 glider pilot by the way, and really generally a glider pilot by heart, after all.
As the wind picks up the flight times go down though, as he is forced to throttle up to keep the light plane from simply blowing away.
 
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Bob A

New member
#51
Here's a question for you 'experienced' Kraken builders and pilots; I was watching the Spear build and in there it was stated that the tape hinge system for the flaperons sometimes gave way on the Kraken because of the waterproof paper so on the Spear, Bixler developed a newer system for attachment. Just wondered if I could reduce the size of the existing flaperon by 1/2" during construction to take advantage of this new, better hinge system to avoid possible hinge/tape separation? OR, should I cut some 'new' flaperons with the extended width so they wil end up as planned?
 
#52
Hello!
I just started my Kraken scratch build. I was wondering about the motors used in many episodes.
Does anyone know what motors were used in this videos? DT700, DT750, D4023? They look all the same...
Thanks!
 
#54
What does refreshed mean? BTW i tried printing several plans to see how off they where and the Kraken plans was the only one that came out on scale. For the rest i will have to figure out how to print them in smaller size.
 

SP0NZ

FT CAD Gremlin
Mentor
#55
What does refreshed mean? BTW i tried printing several plans to see how off they where and the Kraken plans was the only one that came out on scale. For the rest i will have to figure out how to print them in smaller size.
Refreshed means redrawn using the latest format for the plans.
 

SlingShot

Maneuvering With Purpose
#58
Cut out all 8 main pieces for the wing panels. When you get a SBK you get an extra set of both wing spars and elevons.

Josh Bixler opines, in the build video, that this is a "satisfying build". I can second that emotion. For a scratch build, it's really nice that you get such a big plane with mostly straight line cuts. I think that I spent more time tiling the plans and making my templates, than I spent cutting the foamboard.


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