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Old Oct 02, 2012, 06:53 PM
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Leadfeather I have a new DX8 TX. Being that all of the edfs are controlled by the kk board how could I cut signal to the front esc?
Thanks
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Old Oct 02, 2012, 08:06 PM
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So I cut a intake hole in the top of the fuselage directly over the rear fans to see if somehow that was the reason that it wouldn't lift off from pavement. No go, whats the deal! Set it on grass it takes off right away with no problem and hovers a click over half throttle. Set it on the driveway and she will rev all day but no lift. Im at a loss of what the issue is. I would like the final product to be able to taxie out on the runway then vtol up in the air then switch to forward flight but at this point she is for some reason an off the runway machine. I need input guys, what do you think?
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Old Oct 02, 2012, 08:16 PM
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Landing gear I think should solve your problem. Anything to prop it up off the ground
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Old Oct 03, 2012, 12:16 PM
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Hi...I wonder,when you tilt the 2 rear fan,backwards,how they will behave in flight!?IMHO,i think,they will be react like rudder and not like roll!!When the plane rolling,the fans increase ans decrease speed and will push the plane left and right!?
Is that so!??
Cheers
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Old Oct 03, 2012, 12:17 PM
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It has to be raised a good little bit above the pavement to lift off. Higher than I was planning on making the landing gear. I have made some little foam legs to lift it up a bit untill i get the landing gear developed but looks like I may have to go a little higher.
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Old Oct 03, 2012, 01:03 PM
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Originally Posted by nadine View Post
Hi...I wonder,when you tilt the 2 rear fan,backwards,how they will behave in flight!?IMHO,i think,they will be react like rudder and not like roll!!When the plane rolling,the fans increase ans decrease speed and will push the plane left and right!?
Is that so!??
Cheers
I have seen this plane and worked a little with superchomper on it. We haven't gotten to forward flight yet but that does bring up a valid point. We'll have to see about that when the VTOL issues are all ironed out.

On the concrete vs grass debate, it is like concrete causes the thrust to dissipate more so than on grass. The height of the plane is the same whether on grass or concrete. The only thing that I can think is that maybe the grass is deflecting the thrust back into the bottom of the fuselage and providing the extra lift needed to lift off.
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Old Oct 03, 2012, 05:48 PM
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Nadine, the rear edfs are in the center of the fuselage and will shoot all the way through the fuse before coming out the rear where I will have a thrust vectoring setup, so I doubt it will make much of any difference at all, I am using a 8 channel set up and have the elevator and aileron port controlling the elevons and aux2 and aux3 sending signal to the kk board. I could make the channels mixed to the kk board turn off when in forward flight but I don't think I will need to because when I give left aileron it will slow the left edf and increase the right edf thus working like rudder mixed with aileron control. (This is what im thinking anyway) I know even if the mixes are turned off that the gyro will still control the speed of the edf units a bit but I honestly don't think it will be enough to even tell. I guess we will see.

Constant Im going to go up and do a quick glue job and hopefully we can get a little more testing in before the sun disappears. I hate it getting dark earlier!
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Old Oct 04, 2012, 12:41 AM
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Originally Posted by superchomper2003 View Post
So I cut a intake hole in the top of the fuselage directly over the rear fans to see if somehow that was the reason that it wouldn't lift off from pavement. No go, whats the deal! Set it on grass it takes off right away with no problem and hovers a click over half throttle. Set it on the driveway and she will rev all day but no lift. Im at a loss of what the issue is. I would like the final product to be able to taxie out on the runway then vtol up in the air then switch to forward flight but at this point she is for some reason an off the runway machine. I need input guys, what do you think?

This looks like a Bernoulli effect. When the A/C is sitting on a hard surface and you start the fans, the air is forced out through a thin gap at relatively high speed. This results in low pressure underneath, so it gets sucked down. A bit like a ping pong ball over a pipe with air blowing through it. I thought I'd try and see see the same effect by getting a drinking straw and a small piece of tissue paper. Hold the paper over the end of the straw, then blow through the straw. That didn't work though and the paper blew away. I'm sure it worked when I was at school
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Old Oct 04, 2012, 09:39 AM
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ha possibly so Lazy,
Me and constant went out yesterday evening and did some more testing. I have gear on it now and elevons and all. Even with gear it wouldn't lift off from concrete but still takes right off from grass. I haven't tried any forward flight yet because I don't have a switch to shut the front edf down yet. I have a on off switch ordered that plugs into the receiver and will cut the signal wire to the front edf when a certain channel goes over 50%. I will y it into the same channel that is controlling the tilt of the rear edfs so as they surpass 50% on there transition to forward flight the front edf will shut down. I think this should work as the way I have the rear edf pivot system set up it should have sufficient forward flight for the wings to sustain lift by this point. This is all in my head though so I hope it works in the rear world! Hoping the switch will come in this weekend and we can get some transition test in!
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Old Oct 04, 2012, 01:24 PM
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Goodluck!....I did'nt know that you use 8 channel radio!...Hope do you have a good result!
Cheers...
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Old Oct 04, 2012, 03:29 PM
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Quote:
Originally Posted by superchomper2003 View Post
Leadfeather I have a new DX8 TX. Being that all of the edfs are controlled by the kk board how could I cut signal to the front esc?
Thanks
Rx controlled switch...maybe?
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Old Oct 05, 2012, 10:24 AM
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Leadfeather I actually have one of those switches ordered just have to wait for it to come in.
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Old Oct 05, 2012, 10:36 AM
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She is completely together now and should be forward flight capable. (I hope anyways) Im worried about how it will fly being as heavy as it is! I don't think it will be able to transition yet unless my switch comes in the mail today. Wonder if I could mix some kind of down elevator in to compensate for the front fan still running? Probably wouldn't work very well. May try forward flight this weekend and see how she works out. I need to get some pictures of this thing!
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Old Oct 05, 2012, 11:13 AM
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Best of luck! I hope you get to video tape the maiden flight.
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Old Oct 05, 2012, 12:56 PM
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I plan to! Plus the switch just got here so I will get that installed and and try some transitioning!
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