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Old Jul 01, 2012, 01:59 PM
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United States, MI, Paw Paw
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Originally Posted by Joe 1320 View Post
The problem is the shape of the F-86 intake duct is not so good, the model suffers from low static thrust because of that intake. Adding a thrust tube and reducing the exit size would further reduce static thrust..... not so good in this case. After adding the cheater duct, reducing the exit size may be of some benefit, I haven't had the opportunity to test that part yet.
I also did the cheater hole mod that Joe posted. It really did make a difference. In the air, you cant even see it. I have flown it by with a few people on the side lines and we were trying to spot it but seriously, its not visible even at lower speed passes. With 3s and the cheater hole, its impressively fast for what it is.
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Old Jul 01, 2012, 02:11 PM
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Chicago, IL
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Okay, this is what I've heard about cheater holes, yes, they improve static thrust, but don't add much when the plane is flying. I've even heard that they can reduce efficiency in the air. My F-86 launches fine, so static thrust isn't an issue. What has been everyone else's experience? I think I remember at least one person who said adding the cheater hole improved flying speed.
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Old Jul 01, 2012, 02:38 PM
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The cheater hole mod made my plane on 2s a bit quicker, and it just flew better. I was able to loop pretty well where as before, it was nightmarish. Also removing the wing tanks made a huge difference as well. I have since then gone through 2 aileron servos since its pretty bare down there but its well worth it for the decrease in drag If you are worried about it just cut it cleanly into a rectangle and keep that piece of foam. If you dont like it put a dab of glue on and get a silver paint sharpie. Its almost an identical match. You will never know you cut it out!
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Old Jul 01, 2012, 03:03 PM
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United States, FL, Sebring
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The whole reason I posted the cheater mod was that I felt the F-86 was a pig out of the box. Yes, it would fly.... but if the plane got off step or was flying downwind, one false move and down it went. A bad launch, and down it went. It was terrible on recovery. A look at the duct, I could see the way it necked down for the battery tray and right away knew that it was not flowing well. the panel was cut out and took a flight and have been happy ever since. the back edge was also beveled so that it was a more straight shot to the fan. Not one bad launch since, not one downwind dump, the plane flys like it should have in the first place. At some point I'll step up to 3s like a few others in the hanger, but at least it flys well enough now that I can at least wait until these lipos die. It's a little quicker, it's definately got more thrust, much more of a joy to fly.
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Last edited by Joe 1320; Jul 01, 2012 at 03:09 PM.
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Old Jul 01, 2012, 03:06 PM
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Chicago, IL
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Guess I'll bite the bullet and try a cheater hole, like you say, I can always put it back. I never flew with the drop tanks, part of the reason mIne flies well, I believe. It does barely loop, that would be good to improve.
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Old Jul 01, 2012, 03:07 PM
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P. S. - I always land on grass, so not having the drop tanks isn't an issue.
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Old Jul 01, 2012, 03:14 PM
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Nederland, GE, Wageningen
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I have never had any problems when flying 3s. I haven't changed anything about the ducting and it flies just great: Plenty of power, high speeds and I can let it go up vertically untill a complete stop (No throttle), after which it drops its nose and just flies off again.
I never fly with the droptanks, and I've never felt the need for a cheater hole.
On 2 cells; Meh... On 3 cells: Yay!
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Old Jul 01, 2012, 03:26 PM
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I guess the cheater hole is for the people struggling on 2s but not wanting to up to 3s. I lean more towards scale than speed. I run on 3s so is so far fine.
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Old Jul 01, 2012, 06:54 PM
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You nailed it exactly, I'm already set on 2s, don't want the expense or hassle of swapping the ESC and getting new batteries. It's pretty close to where I want it on 2s, if a cheater hole gets me just a little more, great.
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Old Jul 01, 2012, 07:18 PM
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Took the drop tanks off the F-86 and went for a few flights. Ditching them made a noticeable difference. Lost the servo connecting rods on landing, but that's no big deal. Speed was a little faster, loops were nice. Still going to put the tanks back on for landings but it's nice to know performance picked up even more.
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Old Jul 01, 2012, 08:45 PM
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What batteries do you use? I use the Nano-Tech 370mah 11.1v 25c.
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Old Jul 01, 2012, 08:48 PM
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What batteries do you use? I use the Nano-Tech 370mah 11.1v 25c.
I am using the Turnigy Nano-Tech 460mah 3s 11.1v packs. love em
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Old Jul 01, 2012, 10:12 PM
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Put in the cheater hole, did two flights this evening. Doesn't seem any different, if anything, it's worse, it won't loop anymore. I think this is because the cheater hole is creating a low pressure area under the wing, once the plane starts slowing down on the up line, it doesn't have enough lift to push it over.

I'm bringing out the foam plug next time, and will do back to back flights with and without the cheater hole, but I get the feeling I'll be putting it back in.
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Old Jul 01, 2012, 10:53 PM
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Originally Posted by Angelo View Post
Put in the cheater hole, did two flights this evening. Doesn't seem any different, if anything, it's worse, it won't loop anymore. I think this is because the cheater hole is creating a low pressure area under the wing, once the plane starts slowing down on the up line, it doesn't have enough lift to push it over.

I'm bringing out the foam plug next time, and will do back to back flights with and without the cheater hole, but I get the feeling I'll be putting it back in.
Did you cut it as Joe instructed so it has the beveled edge in the back? Not sure why yours isnt showing much improvement. Maybe you should just jump to 3s?
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Old Jul 02, 2012, 08:23 AM
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Quote:
Originally Posted by Angelo View Post
Put in the cheater hole, did two flights this evening. Doesn't seem any different, if anything, it's worse, it won't loop anymore. I think this is because the cheater hole is creating a low pressure area under the wing, once the plane starts slowing down on the up line, it doesn't have enough lift to push it over.

I'm bringing out the foam plug next time, and will do back to back flights with and without the cheater hole, but I get the feeling I'll be putting it back in.
Odd. Mine was a pig prior to the cheater duct. If you think about it, the cheater hole is behind the CG... so if there were a low pressure area, it would pull the tail under the centerline. In theory, it should aid in a loop. Hmmm..... oh well, there's always the exception so it's good that the panel can be put right back into place if it's not working for you.
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