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Xtreme F-16 1/6.75

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Xtreme F-16 1/6.75

Old 02-11-2021, 04:28 AM
  #301  
stealdesk
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Originally Posted by Dieselman1220 View Post
That does not sound right?
mine needed minimal weight up front with a 140 turbine.
Is your rudder set up stock or in the alternate installation?
Thanks
Old 02-11-2021, 05:47 PM
  #302  
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Rudder setup stock per instructions. K160 engine.Don't understand why it is so tail heavy. Weight is 27 lbs dry. Balancing with tanks empty, wheels down, no UAT, no cockpit either. Balancing about an inch back from the 190 mm recommending in instructions. That is with 2 lbs of lead in nose already. Just doesn't make sense to me. Looking for ideas on what could be wrong.

Terry
Old 02-11-2021, 06:31 PM
  #303  
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Originally Posted by tlj125 View Post
Rudder setup stock per instructions. K160 engine.Don't understand why it is so tail heavy. Weight is 27 lbs dry. Balancing with tanks empty, wheels down, no UAT, no cockpit either. Balancing about an inch back from the 190 mm recommending in instructions. That is with 2 lbs of lead in nose already. Just doesn't make sense to me. Looking for ideas on what could be wrong.

Terry
I don't have one of these but usually the UAT would be full which is usually a 4 fluid oz of fuel size and a full cockpit with pilot will be somewhere in 8 oz to 1lb range. This still leaves about a pound of weight needed.
Old 02-28-2021, 04:22 PM
  #304  
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Performed maiden today. The plane flew very nose heavy although balance was 190mm back from LE of wing at root as per instructions. So obviously this balance point is not accurate. Does anyone know what the CG should really be? I've e-mailed Extreme Jets and received no reply.as yet.I just don't understand how the manufacturer could be so far off on the CG for this airplane.The plane flew well otherwise. Landed very nose high and pretty slow.

Terry
Old 02-28-2021, 05:51 PM
  #305  
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If it easily landed nose high and slow then it probably was not that tail heavy.
Where are the training edge of your Stabs in relation to the speed breaks?
If you feel comfortable move the CG back another 10mm.
Old 02-28-2021, 09:03 PM
  #306  
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info on this sheet says 180. mine flys great, lands same as yours. elevators are almost 1/8 " up trim. same info and pictures of elevators in earlier post. adjust the cg to your style. most cg info posted is a starting point. a few flights in similar conditions helps determine what's best.
Old 02-28-2021, 09:05 PM
  #307  
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see post 274 & 275
Old 03-01-2021, 06:23 PM
  #308  
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This is what it took to balance at 190 mm:




Old 03-01-2021, 06:25 PM
  #309  
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The plane flew nose heavy. So the 190 mm balance point cannot be correct. Here is the plane just before maiden:



Old 03-01-2021, 06:39 PM
  #310  
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Here is where the elevators trimmed after first flight:



Old 03-01-2021, 06:54 PM
  #311  
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The front gear door never closed during the flight. Works fine on the ground. Anyone else having this issue? How was it resolved?

Terry
Old 03-01-2021, 07:11 PM
  #312  
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had to modify the door for the wheel to fit. then repaint.


that's a lot of lead.
I put my turbine lipo there. my 8 oz + - lead square inside the bulkhead
Old 03-01-2021, 07:42 PM
  #313  
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flew mine with cockpit tub and pilot, that may be a difference
Old 03-01-2021, 11:22 PM
  #314  
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Your stabs look good, add the pilot and cockpit.
Also where is your UAT located?
mine was right behind the cockpit.
Old 03-02-2021, 07:20 AM
  #315  
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I have two 2700 mah receiver packs in nose. Fuel pump, ECU batt and air valves behind nose bulkhead. Cockpit with pilot,receiver and gyro under cockpit. UAT behind cockpit and 1800 mah afterburner light batt. that I move around to fine tune C/G { currently behind UAT }. I would have to check to see where my C/G is now but the plane flies very well, Nose is very controllable on landing approach. Stabilator's are trimmed up 1/8" which seems to be the norm, no lead in plane.

Scott
Old 03-03-2021, 02:33 PM
  #316  
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Joseph- I do not use a UAT. Stopped using those about a decade ago after crashes and deadstick landings due to UAT failures. I find UAT is not needed at all. Just causes problems. That has been my experience anyway. I will add the cockpit later and maybe a pilot. That should make some difference for sure. Thank you for the comments. Terry
Old 03-03-2021, 02:36 PM
  #317  
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Scott- If you get the chance, check CG and let me know where your at. Maybe you are more like 200 mm. I think I will try that next. First flight just seemed too nose heavy to me. Thanks for sharing. Terry
Old 03-04-2021, 05:44 AM
  #318  
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I will check my C/G within a couple of days. { plane stored in trailer} Mine flew nose heavy also on first flights, moving afterburner light battery helped. so I believe it is behind their range.

Scott
Old 03-05-2021, 08:55 AM
  #319  
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Just checked my C/G, It is 195. I think it could go back a little more.

Scott
Old 03-05-2021, 04:12 PM
  #320  
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Thanks Scott. I''m going to try 200mm. Let you know how it goes.

Terry
Old 04-20-2021, 06:07 AM
  #321  
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Originally Posted by tlj125 View Post
Thanks Scott. I''m going to try 200mm. Let you know how it goes.

Terry
Have you flown it at 200mm?
Old 05-02-2021, 07:48 PM
  #322  
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I test flew the jet with the CG at 190mm. Mine is at 29lbs with UAT full. For power I have a Swiwin 120. I was worried it was too heavy but it flew pretty good. I have an old version 1 with the glass fiber fuselage not airex. The previous owner put lead shot in the elevator to dynamic balance them which makes me add more weight in the nose. I was told it has never been flown. I am going to replace the elevators to make it lighter and going to reinforce the wing mount in the fuselage as this is a weak point and the have been some that have fail there.
Old 05-03-2021, 02:52 AM
  #323  
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I saw one pilot get the dreaded "wing off light" illuminate last week.
Old 05-03-2021, 12:34 PM
  #324  
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Originally Posted by tp777fo View Post
I saw one pilot get the dreaded "wing off light" illuminate last week.
Yes a friend of mine saw it happen and warned me to take it easy with it. He sent me a picture of the wing so I can see where the weak point is. You can see the area that needs reinforced right where the bulkhead is notched for the engine mount. There is very little support there. I am hoping to have it back together for the war bird event this weekend.

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