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Pilot-rc Predator 1.8m

Old 03-28-2020, 11:21 AM
  #101  
BarracudaHockey
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It was scary, I thought it was a goner
Old 03-28-2020, 01:15 PM
  #102  
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Originally Posted by Flyin_Low View Post
Hey Guys, I have been thinking about the cg... According to the video from Pilot they balanced the Predator with the gear down (the red and white plane). I balanced mine with the gear down using the xicoy balancer and a full UAT (I am about .1lb nose heavy) and just like the image Jeremy posted I have to add a little up elevator for level flight. To me everything looks good. My area just went under quarantine so, therefore, I have to wait a little while before I can get to fly. So take videos so I can enjoy some Predator flights... and enjoy!!!
If you can, while its balanced with the gear down, retract your gear and watch the cg shift and the planes tail drop. This is because the nose gear is moving rewards as it retracts. C.G needs to be balanced with the gear retracted. I had this confirmed Pilot RC as well. They simply advised it Is balanced with full uat and gear up. no fuel in main tank.

Cheers

Jeremy
Old 03-28-2020, 04:02 PM
  #103  
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Originally Posted by Jeremy_D View Post
If you can, while its balanced with the gear down, retract your gear and watch the cg shift and the planes tail drop. This is because the nose gear is moving rewards as it retracts. C.G needs to be balanced with the gear retracted. I had this confirmed Pilot RC as well. They simply advised it Is balanced with full uat and gear up. no fuel in main tank.

Cheers

Jeremy
cant use the xicoy with the gear up
Old 03-28-2020, 05:40 PM
  #104  
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Originally Posted by sipixx View Post
cant use the xicoy with the gear up
True 😂 I used the cg tool they included when I did mine. I used a broom handle to hold the wires and sat it on a couple of a-frames to keep it elevated just off the ground
Old 03-29-2020, 04:33 AM
  #105  
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Let me know your thoughts.... I have read somewhere (maybe on in the manual) that the tanks should be empty and the gear should be up, but... I did my cg with the UAT full and gear down with xicoy and came in about .1lbs nose heavy. I figured that would be plenty of weight when the nose gear retracted. As you can see in the first video, I did stall and it fell nose first and recovered quickly. I don't think the weight of the nose gear shifting towards the rear will make a significant difference in the cg. I know it there will be a shift due to the weight of the wheel and strut retracting but that should be about it??? I think we might get caught up in the numbers, set it up as close as possible to the manufactures recommendations and make adjustments as desired... just my thoughts...
Old 03-29-2020, 04:38 AM
  #106  
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C&G is always with the gear down...personally I also always put a little bit of fuel in the main tank....never ever landed with it completely dry
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Old 03-29-2020, 07:17 AM
  #107  
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Originally Posted by Dansy View Post
C&G is always with the gear down...personally I also always put a little bit of fuel in the main tank....never ever landed with it completely dry
I would agree with everything you mentioned here.
Old 03-29-2020, 07:49 AM
  #108  
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Originally Posted by Dansy View Post
C&G is always with the gear down...personally I also always put a little bit of fuel in the main tank....never ever landed with it completely dry
Phew... I was beginning to wonder if I was one of the few that did it that way...
Old 03-29-2020, 04:06 PM
  #109  
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Photo by Tony Lively

Thanks to Tony Lively
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Old 03-29-2020, 04:44 PM
  #110  
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Originally Posted by MikePS View Post
Maiden report: um....scary! Several stalls kept me feeling as though I was not going to get this jet back on the ground in one piece. Even though I had checked the cg, throws, etc. several times I'll go back over them again. My AUW with half a tank of fuel was 21.75 lbs. I know that's well over what the spec is. I expect it contributed to the problem...may by replacing the 100 with an 85.
with an empty tank, uat full, on level ground with gear down, if you put it in a wheelie does it stay there? If it stays there and doesn't easily fall back to the nose with a light tap, you're tailheavy.
also, CROW! It will work wonders at preventing a stall, or at least giving you more warning. Only takes about 1/4" of up aileron.
why is yours so heavy? Is the 100 than much heavier than the 85? Did you add lead somewhere, or smoke?
I believe the Rebel HOT is very similar in size to the predator 1.8, and people gave me flack for building it like a 'tank' at 16lbs take off(13.25 dry).

Last edited by bodywerks; 03-29-2020 at 04:49 PM.
Old 03-30-2020, 02:45 AM
  #111  
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Originally Posted by MikePS View Post
Maiden report: um....scary! Several stalls kept me feeling as though I was not going to get this jet back on the ground in one piece. Even though I had checked the cg, throws, etc. several times I'll go back over them again. My AUW with half a tank of fuel was 21.75 lbs. I know that's well over what the spec is. I expect it contributed to the problem...may by replacing the 100 with an 85.
Hi Mike, on my maiden and my second flight I stalled too. With the throws on the elevator I noticed that I need to take wider turns. So I added a little more expo to the elevator and have not had that problem since.
Old 03-30-2020, 04:18 AM
  #112  
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Originally Posted by Flyin_Low View Post
Hi Mike, on my maiden and my second flight I stalled too. With the throws on the elevator I noticed that I need to take wider turns. So I added a little more expo to the elevator and have not had that problem since.
What radio do you use and how much expo did you put on the elevator ?

Cheers
Old 03-30-2020, 04:22 AM
  #113  
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Originally Posted by sipixx View Post
What radio do you use and how much expo did you put on the elevator ?

Cheers
ix12 - 30%
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Old 03-30-2020, 08:07 AM
  #114  
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I used the Pilotrc spec'd servos, their UAT...I didn't add any lead, but did have to put a 3800mAh 3S Life in the nose, along with 2 2100mAh 2s Lifes in order to hit the CG. I didn't try the "push the tail down" CG method but as you can see in the picture at the beginning of the post, it was balanced right at 223...The K100G weighs 2lbs, 14oz. The K85G2 weighs 1lb, 13oz. Less weight there will allow me to use a lighter ECU battery. Hopefully save another 6oz. May even replace the UAT with a smaller one and save a few oz there too. As far as throws and expo goes, I was at the spec'd rate at takeoff and had 40 points of expo on the elevator at high rates, 25 at low. I do have crow mixed in with full flaps, about 5mmr worth. I have experienced a stall with my 2.2m Predator, getting a little slow coming over the top of a loop, this was something very different, seeming to fall out in the turns...but not particularly steep banked ones.
Old 03-30-2020, 09:02 AM
  #115  
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Originally Posted by MikePS View Post
I used the Pilotrc spec'd servos, their UAT...I didn't add any lead, but did have to put a 3800mAh 3S Life in the nose, along with 2 2100mAh 2s Lifes in order to hit the CG. I didn't try the "push the tail down" CG method but as you can see in the picture at the beginning of the post, it was balanced right at 223...The K100G weighs 2lbs, 14oz. The K85G2 weighs 1lb, 13oz. Less weight there will allow me to use a lighter ECU battery. Hopefully save another 6oz. May even replace the UAT with a smaller one and save a few oz there too. As far as throws and expo goes, I was at the spec'd rate at takeoff and had 40 points of expo on the elevator at high rates, 25 at low. I do have crow mixed in with full flaps, about 5mmr worth. I have experienced a stall with my 2.2m Predator, getting a little slow coming over the top of a loop, this was something very different, seeming to fall out in the turns...but not particularly steep banked ones.
Everything sounds good to me...

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