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Old Oct 04, 2013, 08:35 PM
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AS3X transplants: Great Planes F-86.

Though this transplant has been done by at least a couple of people, there seems to be no dedicated thread. Figured I would briefly break down my experience.

Parts used:
GP F-86 airframe, Hyperflow edf unit. rudder linkage, aileron linkage, part of elevator linkage.
Mig 15 AS3X rx, 3 2030L linear servos. elevator linkages.

The F-86 was bisected laterally at seams. The outer shell and the inner duct shell were cut simultaneously, and the stock parts removed from the top half.(aileron servo removed at a later point).
The Mig's elevator linkages when installed determined the servo position, glued to the top inside of the top outer shell, large gear toward the nose. The rudder servo was mounted in the same way, directly behind the elevator servo. The F-86 rudder linkage was used, requiring that it be cut, kick-bent, and shrink-tubed together. The cut was made at a point far enough forward that the joint would not affect linkage travel through the channelled path to the control horn.
A single servo was used to operate ailerons. A hatch was cut in the underbelly over the stock servo, with the back edge of the hatch running through the linkage slots so that the slot holes themselves would remain on the hatch. The stock servo was removed at this point. A linear servo with the linkage hole slightly reamed was pressed onto the pin in the center of the aileron linkage. With ailerons neutral positioned, the servo was affixed to the underbelly. I believe the gear was toward the left wing, will confirm. There were clearance issues between the linkage and the gear. This was resolved by using a peice of the F-86elevator control linkage.First, (with wings/fuse bottom inverted on table)the involved aileron linkage was cut at the plastic centerpiece and removed. then the centerpin was pushed back out of the servo, and a peice of shrink-tube slid onto the remaining aileron linkage. The centerpin was placed back in the servo. A peice of the elevator linkage was cut long enough to fit into the empty aileron bellcrank, pass over the plastic centerpeice, (opposite to the servo, creating the required clearance from the gear), and be entered into the shrink-tube on the linkage on the other side. In this position, with ailerons neutral positioned, the shrink tube was heated to lock correct linkage length and position. linkage was carefully glued to plastic centerpeice as well.
The black plastic base inside the canopy was removed, except for the vertical crossmember. A cooling hole was reamed into the front windscreen.
clearance was cut for the AS3X to be installed in the cockpit with battery and esc wires oriented to the back of the plane. It was positioned forward to the point that it tucked under the battery, with the servo ports up against it. The built in esc was used to run the Hyperflow fan unit, wires were cut to length and spliced in. Wire crossing in relation to colors was required for the fan to operate in correct rotation.
This plane has been sucessfully flown several times now, but with several bugs worked out along the way. There is an unexpected need to still add weight to the nose, inspite of a significant weight increase and forward shift in relation to the stock model. The final flying weight with ballast was a somewhat hefty 74.5g.
The plane was initially over-responsive, so rate and expo were adjusted accordingly. AS3X improves its tracking, however, there is still the occasional "Sabre dance" in this case.
Still playing with the fine tuning of the plane, and adjusting to it, it has a pretty different feel compared to stock. Overall, I'm pretty happy with it so far. There are a couple of things that would be done differently next time though, in light of the weight/cog situation with this build. The servos could have been further forward, either with all new linkages, or by placing the rudder servo in front of the elevator servo(requiring a more complicated linkage for clearances).
The stock esc would be used. The built in esc of the rx hasn't cut out once, yet, in a side by side comparison with one of my stock F-86s, the full-throttle rpms were audibly higher with the stock esc, and the motor/fan unit used in the build were fresh. It doesn't affect performance envelope very much, but its there. Better to throw the esc up front for ballast and performance reasons, apparently.
I probably will do this build again, once this frame is beat.

Hope this was helpful and easy to find.
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Old Oct 06, 2013, 05:00 PM
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adding to your resource with some posts i saw by Eric Henderson on the sabre thread regarding the same topic: http://www.rcgroups.com/forums/showt...73648&page=169
thanks for starting a dedicated thread.
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Old Oct 06, 2013, 06:58 PM
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Glad you started this thread!!!...I have so many irons in the fire with my two sons activities I haven't had much time to play with the mod...Plus I bought a new FMS 1400mm BBD P-51 that now is garnering all of my love......I need longer control arms for the ailerons on the F-86---Finding these in the right length has been troublesome...

Kevin
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Old Oct 06, 2013, 08:33 PM
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Well, there's an "s" at the end of "transplants" for good reason, by all means, feel free to piggyback any similar projects here when you get time to make a lil progress on them!
Among other things,I'm interested to see if anyone elses build also requires the suprising amount of ballast mine does, ..somewhat puzzling to me....
EDIT: Kevin, what about the 86s stock aileron linkages? Shrink a z-bent wire with a v-bend for trimming onto the cf, and you'ld be on your way, no?
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Old Jan 06, 2014, 01:41 PM
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Update: Sheared a wing off after a Mechanical failure in the aileron linkage, my own fault. The pin slipped out of the hole at the aileron servo. I should have prevented that by flaring the end of the pin after installation, or by glueing, ect.

Just a heads up for those who may be considering this type of setup.

Even though it was flying nicely,this airframe was pretty tired anyways. I think the tail re-enforcements were the culprit where weight was concerned, and I needed to open it up to put the stock esc back into the mix too. It will be retired oweing me nothing, a lot of R and D came out of it, the transplant will be direct with no fab req'd. ....now, do I get a new airframe, or turn another of my stock 86's into a donor? Time to do some pricing....

A question occurred to me though regarding RX orientation. As it turns out, when I mounted the RX in the 86, I rotated it 180 deg. What was the front edge when installed in the Mig ended up at the back in the 86.
Why didn't this screw with the gyro-stabilization? Should that not have amplified pitch and roll instabilities, instead of stabilizing them? I'm glad that it seemed to still work fine, its just curious to me....
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Old Jan 06, 2014, 07:36 PM
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Ok, so I think I have all the soldering done(Y-harness from batt to RX and esc, HH servo plug on GP F86 esc(brown to black, red to red, orange to white?), connector btwn esc and motor), and I know how to plug it into the Xport.
Now i need to figure out how to set up my Dx6i programming, anybody care to offer the play-by-play? I think I'm in the ballpark, but the manual seems a bit vague?

Also, I don't have any servos with me, just the rx, esc, motor/fan, a lipo, Dx6i. Do I need servos to initialize and test run the motor?
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Old Jan 07, 2014, 03:18 PM
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just plug in the motor to the brick and it will run, no need to plug-in servo channels. make sure to keep the brick still and flat. iirc, as3x planes (um spit, umx mig) run just fine on linear, no need for expo. so no need to setup anything special on the DX6i.
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Old Jan 07, 2014, 04:31 PM
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Thanks, I managed to get the motor turning last nite with no servos plugged in, so now I know that much.
Problem now is that a) its turning backwards. swaping two wires btwn the esc(note: external) and the motor typically resolves that, and b) its stuttering and running slowly. This causes me to wonder if the wires between the GP esc (F-86 6amp) and the HH servo plug have been mismatched color-wise. I went black to brown, red to red, white to orange. Is this correct?
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Old Jan 07, 2014, 04:52 PM
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your color code sounds correct but i cannot verify since i gave all my micro gear away to a flying mate on my field sometime back. either way, i'm quite sure its right.
i note you are using the GP ESC. i don't see why its got problems running the right way unless there is a bad connection somewhere. i would check connections first.
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Old Jan 07, 2014, 07:01 PM
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I swapped two wires btwn the esc and motor. As expected, the fan spin is now in the right direction. It also runs at full power. It still stutters intermittantly when throttle is applied or manipulated though. Completely unreliable. Also, throttle doesn't engage until I'm at 50% on the stick, so I still have that to figure out.

It seems that Mix 1 and Mix 2 both have to be activated to arm the esc. I didn't expect that. I've set both THRO>GEAR. What should my left and right values be? I've been leaving my right value at 100%, but the left value doesn't seem to affect any apparent change in function until its taken into the negative values, at which point the esc wont arm.

Incidentially, I'm using a HH escconnector btwn the esc and motor, and since i didn't think I had shrink tube with me, I simply shaved the guide tabs off of the male connector, flipped it, and it plugs right back in. Handy. Wasn't sure the spacings would work out for that, but it seems its close enough. Fine actually....
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Old Jan 07, 2014, 07:13 PM
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i know the GP ESC has an arming sequence: one full movement of throttle stick and then back again. but that doesn't explain the 50% which is strange. i may be way off but i wonder if its a binding issue since it almost seems like a throttle trim issue. either way, that ESC for sure can handle the motor - iirc, the ESC amp rating is a bit higher than the one on the Mig 15 brick.
still suspecting the connections for now. hope you find the problem.
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Old Jan 07, 2014, 09:45 PM
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Roger on the arming sequence. In this particular case, the first beep occurs at full throttle. Interesting to me is how the second beep occurs as the downstroke on the stick reaches about 35%. I don't have another plane with me to confirm, but I think this is different from my stock F86.

I'm entertaining the notion of bad connections, although I'm pretty diligent about how i make them. Wires do break though, beside even the best of solder joints. I can't feel any breaks through the shrink tube, but they could be there. Could possibly be a resistance issue too.

Another thing I'm considering is the length of wire between the esc and the motor. I've read that this can be an issue when increased too far. The stock configuration length is about 2-3", if I recall correctly. When I ran the motor off the Mig esc, it was 6". Now they're at 8". Perhaps I've pushed the envelope too far? This also might account for the occasional stutters, but seems less likely to be a factor with the throttle engagement point?
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Old Apr 07, 2014, 04:10 PM
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Update: shortened the wires, eliminated three connections. Not sure which variable was causal, but the motor now engages reliably. The start point on the throttle is still a little high on the stick, but the range is full.
Good to go, I think I'll be stripping my NIB F-86 for this, I'll still have my stock "daily driver" for comparison....
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Old Apr 22, 2014, 07:42 PM
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So,.. I've re-done the transplant on a new frame. The first one I did ended up weighing 74.5 g, this one weighs in at 74.8g, 0.3g heavier. Considering that this second build includes the external esc that weighs 4.9g and a power harness for the lipo-esc-rx that weighs 2.6g, I'm satisfied with the slight weight gain for hopefully slightly more power than the first build, with no dead weight. However...

When i went to install the RX, it didn"t work anymore! The light flashes briefly, but the board won't stay on. Its not the wires, its in the board, i"m sad. Without the as3x on board, there's little point to this build. I could fly at stock weight with a lighter Spektrum compatible board, but the stock board and an Anylink fly this plane just as well.

Oh well. I'll buy another board (probably in another MiG-15), and this F-86 can be a hangar queen till then. Will have to do it before I kill my daily driver though, so i can do a side by side comparison.

All in all, this transplant has been reasonably successful. I would say, "worth doing", once definitely, twice maybe, but I don't think i would do it a third time. The stock plane flies great once you're on it. This mod mainly serves to make it more flyable in wind.
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Old May 19, 2015, 09:45 AM
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Have an AR6335 I'm probably gonna stick in this on the weekend. Lighter than the Mig Board.
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