Turbinator (V2) Thread
#30
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We still are able to fly at NALF when we get on the schedule, BUT we are currently waiting on the "Non-Gov't Use" permit to get signed AGAIN!, so we are currently not able to fly at the moment. Last year it took 2-3 months (end of May) before it was signed. I'm afraid it will be same this year because we are low priority. The good thing this time though, it will be good for 5 years, so we won't have to worry about it for awhile once it's done.
#36
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I ended up with a bare very low time airframe from a buddy.. It had the dreamworks gear setup and a 100 sized turbine and would not take off on the very well maintained 800 foot grass runway we sometimes use.. the grass is like Velcro there.. It is the slowest grass I have ever seen.. My gas corsair I can fly in tall grass at home with no problems-- and I mean tall enough you can see the track the prop cuts on takeoff and on landing with no problems, but when on the beautiful 800foot putting green will flip on its back in a heartbeat.... Anyway, the turbinator came in at 27 lbs so dry as I recall. It seemed heavy as heck for what it is to me but it did fly well.. I am thinking phase one is to take the dremel and open the wheel wells to go up 1" in diameter all around on the wheel size and put a 120-140 in it and fly it for a while. If I feel motivated I may put it on a diet and recover it as it looks like it is built like a small plywood tank.. I think bumping it up to 4" mains and a 3-1/4 nose gear would help a lot for longevity and hopefully let it perform on grass better. Should be a simple mod... Anyone running big wheels? and anyone put one on a diet yet?? So far the only jets that I have seen actually make a successful take off from the 800 foot grass were my CARF tutor with 4"1/2 wheels and a way overpowered eurosport 3d and he used a heck of a lot of the grass to get off.
#38
My Feedback: (26)
Put flights 5 and 6 on mine this weekend, original 19 lb Jet Central Rabbit, 23lb dry, 3.5" mains, 2.5" nose wheel on Dreamworks struts and it takes off in half of our 700 grass runway. You've got 4 more lbs of weight but 3 more lbs of thrust I would think your performance ought to be fairly close. You might want to double check your CG and make sure its not nose low when on the ground, also I take off with 1/2 flaps.
#40
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Join Date: Mar 2011
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Hi, I am working on my first jet. I have the boomerang terminator and I am using a King tech 120G. I would like to know why you needed so much down Thrust? I had emailed Larry at Boomerang and he said he used 5 degrees down thrust with a 100 king tech. I am just want to get it right the first time.
#41
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Hi, I am working on my first jet. I have the boomerang terminator and I am using a King tech 120G. I would like to know why you needed so much down Thrust? I had emailed Larry at Boomerang and he said he used 5 degrees down thrust with a 100 king tech. I am just want to get it right the first time.
#42
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Thank for getting back to me, so if you add more down thrust, you would need some up trim in you elevator do to the down thrust pushing the nose down, is the correct. I am not trying to give you a hard time I am just trying to understand.
#43
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Without changing anything from the stock position, the plane will want to climb at full throttle...if you trim for this setting (down elevator trim), when you come off the power, the plane will want to dive. If you trim for 50%-75% throttle, the plane will want to climb/dive apart from trim speed, but to a lesser degree.
The down thrust will will help in this regard. If it doesn't eliminate it completely, it will reduce it significantly enough to not be a big issue.
The down thrust will will help in this regard. If it doesn't eliminate it completely, it will reduce it significantly enough to not be a big issue.
#44
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A down thrust angle proportionally counteracts that, provided you find the right amount for your engine.
Side note comparison: Although the BVM KingCat is in a different league for quality, the Boomerang XL needs no down thrust while the KC is a down-thrust "grass burner". The reason is the Boomer's higher horizontal stabilizer placement, placing the stab out of the exhaust flow's influence.
Last edited by highhorse; 12-17-2016 at 01:04 PM.
#45
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I think I am starting to understand what is happening, so when you increase the throttle to 3/4 up to full, the air on the bottom of the horizontal stabilizer will now be moving faster the air on top of the horizontal stabilizer. I take it that the speed of the exhaust from the engine is causing the air to move faster under the stabilizer then the air on top of the horizontal stabilizer so you are getting two different air speeds acting on the stabilizer at the same time. So that is why the jets that have the exhaust of the engine back past the stabilizer do not have this issue. Am I getting the right? Please give me any info you have. I am sure,I am not the only one that is trying to understand this issue.
I can't thank you enough for your help
T Perk
I can't thank you enough for your help
T Perk
Last edited by TPerk; 12-18-2016 at 03:17 AM.
#48
My Feedback: (3)
A simple non mechanical (adjusting downthrust angle with shims) fix would be a throttle to elevator mix in your transmitter.
Just add % down elevator vs increasing throttle position.
Its the opposite of a downline mix in a pattern plane (adding a few % of down elevator at low/idle throttle)
Personally I would start with adding downthrust and then add the mix if still needed...F3A guys always strive for "no mix" airplanes
Just add % down elevator vs increasing throttle position.
Its the opposite of a downline mix in a pattern plane (adding a few % of down elevator at low/idle throttle)
Personally I would start with adding downthrust and then add the mix if still needed...F3A guys always strive for "no mix" airplanes