EDF Vtol Jet

[Lewist]

I am currently designing and building an EDF vtol jet.

most of the info can be found on this thread - http://www.rcgroups.com/forums/showthread.php?t=434325 (in the EDF section)

Just a quick run down of what i have so far.

I have three SF turbo fans running 3 Graupner speed 400 6volt motors with three cheep 25 amps ESCs, two (soon to be three) MS44 HH gyros, two gws vtail mixers and a jeti RX.

Power is currently being supplied by a 12volt power drill battery via an umbilical chord (will spend on brushless and lipoly once i know it will work!)

the motors at full bore draw about 13 amps each so i am getting about 450 watts.

so far i have a hover test rig and am designing the final plane in CAD. I have had some controlled hovers, but am having a few issues with my own personal piloting skills (not that good!). I have also realised last nite that the tx i have been using has been messing me about. I have a ccpm micro heli and i thought that the ccpm part was done on the RX, but it so transpiers when i used the tx on a plane i have just finished that the ccpm is done on the TX. when i pull up elevator it banks tha ailerons to the right. No wonder i couldn't fly it very well!! DUR!!!

I had got a little dishartened that i was not getting more than a 20 second controlled hover, but i now know why!

Over the next few nights i will be fitting some new undercarrage, and making a better yaw vein. once this is sorted will get the last gyro and finalise the test rig. once this bad boy is all finished i will start on the rear airframe.

please have a read and any comments are welcome!

[Draecam]

Sounds interesting. Got any pictures?

[Lewist]

yeah, if you look on the link above, there is some pics and some cad drawings.

I got the undercarage sorted and a new yaw vein installed and it seams to be doing the trick now i am using a different tx!

[mnfiero]

I have been following your thread and it's looking good. I too have been working on a VTOL EDF project. I'll going to try to post on it soon, just need to get my CAD and pictures rounded up.

You're using SF fans correct? I have one with a broken rotor and I can't find any place that has one locally and anyone I can find to ship one wants like $15 for shipping. Do you happen to know of any (non-ebay) sources?

Good luck and keep up posted.

[v22chap]

Lewist ,,great project ,,have any more vids now that you have the yaw vane in ??

[Lewist]

yes - soon, been off work for the last week so i have got some stuff done on the plane

[Lewist]

Well on Friday last week I took the vtol test rig to Skyline Models (they specalise in Helis) and got the guys there to help me setup the gyros. For those of you following this, Heading Hold gyros are not the way to go. i am currently flying this with the gyros set to normal rate mode. The problem (at least with cheap HH gyros) is the lag. the fans definatly do not respond fast enough, and also when the gyros creap there is an automatic correction that tries to counteract the creap, and that get really upset!

but after all that i got one of the guys there (a much better heliu pilot than me) try to fly here..... and she works.... properly!

he can get indefinate sustained hovers out of it.... so it work!!!! properly confirmed works too.

I still need to work on the yaw control which at the moment is very vaige, but she works!!

I know you guys will want to see a video, so i am going to try and make the yaw control less vaige tonight, and get a video. with better yaw control i am hoping that i will be able to fly it better.

I will take a few pics of the underside of the test rig showing the installation of a few of the control systems, and get a nice little vid.

The chap the skyline did actully do a vid on his modile phone so i might get him to send me that as well!

[v22chap]

Lewist
I am talking with another that is using airplane props for a tilt rotor system and he found that some cheap piezo and most expensive ones return the servo to soon or will lose center ,and will only give about 60 -90 deg travel as you keep turning the gyro in one direction and this is insufficienvt to hover a slow response control bird. you want the gyro to hold their signal longer as the model does not pitch as quick as a heli tail does . To Bench test a servo / gyro combo ,,continuously rotate the gyro in one direction ,,and the serov should travel approx 120 - 150 deg and not return right away .He found the old Arcamx piezo gyro's did the trick .. and then I proceeded to sell him my last two white covered Arcamax's ,,,,duh ,I should have been shot. ;) :rolleyes: :D
Good luck
Larry

[Lewist]

well i know from conversations with Bob at skyline that some of the high end gyros allow you to tell them that you are flying a slughish non responsive model and they will adjust themselves accordingly to take account of that.

[rdresch]

Are we talking delay here? I think it actually does something else to match servo to gyro. Not clear. If someone has more info on the gyro's for vtol lets here it. It's a major problem. It gets even worse when you connect them to cyclic on a rigid rotor head. Too much gain and they oscillate.
Rudy

[v22chap]

Rudy ,, and if you remember ,,Vtolman made the statement in his setup explanation that the arcamax's had to be turned all the way to work right.I would like to find a present model gyro that would do this ,,but he seems to have researched about all of them.My ACT Europe one seems to work fine ,,I will have to bench check it the way he did and see if it applies.

[rdresch]

True, but he is using the gyro to tilt the entire rotorhead, correct? When you use the gyro's on cyclic it seems to be a different animal. The response is so fast that you have to turn the rate down to avoid oscillations. Both pitch and roll need very little gain. Anything over 20 on a Futaba 190 caused problems (crash). I think every one of these vtol's has it's peculiarities and what works for one may not work for another.
Rudy

[Lewist]

If you are taking about a prop based vtol, the rules will be very much different.

The EDF is about the worst choice to use as a lifting device in something that hovers.

they are designed to give lower thrust and higher eflux (exhaust) speed.

[Lewist]

Ok well as promised i have a video of my rig hovering.

I must appologise for the quality of the video, it was taken on a mobile phone, but it does show that it flies!

Many thanks to Bob at skyline models for his help in setting the gyros up and his piloting skills.

the file is a .3gp file (a mobile phone format), unzip it and play it with windows media player - it should work, it might say that the file format is unknown but it should work!

[v22chap]

Lewist ,,that is great to see it more than 4 " off the ground and hovering with yaw control ,,,keep it going man and keep the vids coming as it progress's :D :cool:
Congradulations
Larry

[Lewist]

thanks! I am pleased wiuth how its all worked out.

[Lewist]

UPDATE!!!!!

New workshop has been built in my garden (read as shed!!!) however it now means that i have some more space to work with.......... i am just about to start on an F35 test mule based on a foam F22 raptor fuse i have....

it will be using one front lift fan and one rear fan that can rotate to provide hover lift and forward thrust... again... lack of cash dictates that the mule will most likely be tearthered.... however the man aim is to get the roll reaction control system in place and working...... if it does then we shall try and go all the way!!!!!!!

Lewis

[udo]

hi lewist
succes with your new setup
it can be done... i found this website of a german guy http://www.taileron.de/44.html
check out his videos
grtz udo

[sphericalone]

:eek: im working on the same thing with jetsthanks! I am pleased wiuth how its all worked out.