aps f4u

Ahhhh, A Predator thread! It's nice to see you all I see you have the same issue I had. This is what I had to do to correct it. I had to make a battery tray for my 6 cell li-po pack and screw the end of the tray I made to were the steering servo should have been, extend it to just in front of the wing tube exactly one inch. Just check the pick out, you can kind of see what I did. I have had this for quite a while now and I am just now taking it up for it's maiden this saturday. I'll let you know how it goes. My first attempt was about two weeks ago but I didn't have a big enough esc,(taking off grass runway) so I steped it up from a 70 to 100. That should do it!I may get my friend out there with his video cam and get some footage and put here on RCU. See you soon.

aps f4u

I forgot to note that I also had to use some of that pink foam insulation to help stablize the tray just behind the steering servo tray. you can just barely see some of the foam were it peaks out on the side in the one pic from the top view. I used it because it wieghs nothing and yet is dense enough to hold the tray I made. I used polyurathane to glue the tray to the foam and glued the foam to the fuse. Over all, my Predator came out weighing just between 6.5 and 7 lbs.

aps f4u

Well, it looks like Saturday is going to be put on hold. I was taxiing the Predator around in the back lot yesterday and my esc went poof-up in smoke! So I have another esc on order and should be here early next week. I don't have a clue as to what happened as I had it all working good on the bench and it was taxiing fine and on it's way back to me, it started making a funny noise and by the time I throttled down it was all over? I guess thats how the hobby goes I havn't ever had an esc burn up on me before like this, but I guess there is always a first! So it looks like I will try some time next week to fly this bird as soon as I get the new esc in the mail.

a

Greg Covey

aps,

Thanks for the photos. Where did you end up marking your CG location?

Also, what components are you using in your power system?

Regards.

slevin1

My Feedback: (23)

You should go with a Castle Creations ESC. If something like that ever happens, they replace it for free. Plus their customer service is fantastic! They may be more expensive than other but they are worth it.

Saul

aps f4u

I always use the thickest part of the wing for c.g. if I cant get a good result with the manufactuer's and they have there's set aft of the main wing spar and with the way every thing was to be set up....way nose heavy! So I set the battery in my tray I made slide it around untill I got a good ballance with it at were the aluminum tube goes through (thickest part of the wing) and balanced perfectly and I hope to achieve a good flight that way. If I left the c.g were it was suppose to be, my battery was going to be right in the nose of my fan unit and I didn't want that.

As for my power, I am using some low grade stuff as you can tell but I didn't want to get a lot of money rapped up in such a low cost plane that and I am new to the bigger edf jets too. So here's the skinny: I have Hobby King 33000kv Brushless motor with 4"df unit, 4900 mah 6cell Rinoh li-poly pack with a Hang It R/C 100AMP esc that IS geting replaced for free and should be here early next week. So if every thing goes as planed, I will have it up next week for sure. Keep you all posted!

a

aps f4u

Correction, My c.g is just behind the aluminum tube. After closer inspection and pulling my wings off to see my mark, I was a little off from what I had stated before saying right at the tube. I took about an inch off from what they had originally had (8.4 down to 7.4)

algutkin

My Feedback: (1)

How did the maiden go?

Has anyone got one of these planes in the air yet?

The Himax 96 plug and play setup should be a really good match for this plane, 6S, 1300 watts.

Al

kmp647

Greg any news yet?

kmp647

I see the motor avail is holding you up

this MIGHT be an option

http://www.hobbycity.com/hobbycity/s...hless_Inrunner

$30 its a 36mm 74mm long 1100kv inrunner

a higher rated choice would b the new Medusa products 36-80-1100 v2 motor ratd at 90a for $145.95
http://www.medusaproducts.com/motors/036-V2.htm
just a thought

aps f4u

I ended up selling or should say, having to sell my Predator and a few other planes to a good friend of mine due to lossing my job. I hated to have to do this but in times like this and our economy falling on it's face, I need a roof over my familys head rather than my toy's right now.
My buddy told me I would be able to maiden it though, so I guess there is still an upside to selling an airplane that you really don't want but have too.... to a friend!

Kwesdog

I flew mine last Monday with the 8S2P packs. It flew great but be warned that with those hige ailerons you will need a good amount of expo.

 I also noticed that the landing gear block is one piece and it sucks. If anyone is building this thing I would reenforce the gear block from the topside with another piece of ply and epoxy then just redrill the holes through the new piece. I think they just hot glued the blocks in there because the spread is not uniform. The block will also rip out very easily because it isnt notched into anything so any resistance from rolling forward will be totally absorbed by the glue joint so flying of anything but the smoothest surface will eventually lead to a gear failure.

 Other than the gear problem and a couple of the parts that didnt line up too great this isnt a bad deal for 120-130 bucks. I am thinking if you wanted to venture into 90mm + sized stuff but were worrried about the cost that this plane wouldnt be a bad starting point.

 Harry

Greg Covey

Harry,

Thanks for posting your findings.

I will be resuming my build thread here in just a few days as I have given up on the new release AMMO motor since they pushed the date out to the end of September.

My new Medusa MR-3680-1100V2SE-5 motor should arrive today. I plan to run it on a 12s Lipo supply off of grass so stay tuned...

Regards.

aps f4u

So in other words, I take it  that the Predator has no real bad flying characteristics? I had sold mine to a good friend who has yet to fly it and is planning on getting it up in the next couple of weeks and is going to let me maiden it. I can't wait to fly it as I had it in my shop for what seemed forever to me untill just the begining of the year and then came the axe from the job so it had to go. I think I may tell him to reinforce the landing gear block as well as I noticed that they did pretty much hot glue the whole plane like you stated.
What is the finnished weight of your predator, Kwesdog? I had a 6cell lipoly which went with the predator when I sold it, and it came out around 7.5 lbs. My buddy was thinking of trying to go with some smaller packs in a series because the one I had is a pretty heavy Rhino pack and I know ther are a lot lighter packs out there.

Greg Covey

As expected, my Medusa motor showed up today. My new power system for the Predator UCAV includes the following.
[ul][*] Medusa [link=http://www.medusaproducts.com/motors/036-V2.htm#MR036080XXXX-5]MR-3680-1100V2SE-5[/link][*] Castle Creations [link=http://www.castlecreations.com/products/phoenix_hv_series.html]HV85[/link] ESC[*] Two FlightPower [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXWUD2&P=7]EON28[/link] 6s 3350mAh packs in series
[/ul]

Note that the Medusa V2 motor wires come out at a right angle for an easy exit through the exhaust tube. The motor shaft also has a flat side for the set screw on the Wemotec Midi Pro 5mm adapter to keep it from spinning under high RPMs.

The power system measurements are from Carl Rich. (12s LiPo, 75amps, 3333 watts, 200mph e-flux)

Kwesdog

I will have to throw it back on the scale but with the midi-pro and medusa on 8S the plane has got to be close to if not more than 1 to 1 thrust ratio so I can only imagine what Gregs with do on 12s.

 I didnt modify much of anything on this plane but if a guy were to make some intakes that smoothed the air going into the fan I think this plane would scream. I have wires and crap all in the intake area because of the battery pack set up (there really no way around it unless you make intakes).

 Fun airplane to fly that sounds great. I get so used to flying the buzzy 70mm EDFs that I forget that  90mm and bigger sounds so much better. You hear the thrust of the fan as opposed to the blades spinning.

 APS - I will try and remember to weigh it tonight and post the ###'s. I know the reason I went with the heavier 2P cells was because of the CG. Unless your friend moves whatever fan he has close to the tail of the airplane there is no way to get with in the CG range without having to add weight to the tail. I went with the heavy pack because by moving the packs over the intakes I could get alot of the weight on and just slightly behind the CG. You could get away with 1P packs but they would have to be stubby instead of long cells to keep as much weight out of the front as possible.

 One thing that I can say though that I should have mentioned before is that you should also try and get as much tail throw as possible to help with slow speed. I had to come in on landing FAST because the first landing pass I made with it the elevator got too mushy to soon considering the speed I was going. Not a bad thing just something you need to look out for. Basiclly like flying a larger turbine with a heavier wing loading.

 Harry

aps f4u

I had built a battery tray to put the batteries back further behind the c.g to ballancethe plane better. I posted a pic of my plane on this page at the top. You can kind of see the tray, it puts the battery just in front of the fan but doesnt interupt the airflow as it's above the ducts. I don't know how well it will work as we haven't flown it yet but soon will be and will post results after we do.

As far as elevator throw goes I did add longer control arms as well, so I hope I am covered there too!

Greg Covey

I installed 4mm gold bullet connectors between the motor and ESC. The main power lines got 6mm gold bullet connectors so they don't get hot enough to melt solder. I will make a series adapter with Dean's Ultra connectors for each 6s LiPo pack and 6mm bullet connectors going to the CC HV110 ESC.

Note the 100 ohm resistor used for anti-spark connection on the 12s supply. This worked very well on my larger 4500 watt Byron EDF conversion. Also note how well the 36mm (diameter) x 39mm (length) heat sink fits on this setup.

The Wemotec Midi Pro EDF is the industry leader for efficient 90mm fans. Although the Pro rotor itself can still be used in other ducted fans, I have found that the Wemotec EDF is the easiest to assemble of the 4 manufacturers I have used.

gr8taz nitro

My Feedback: (7)

Hey Greg,
How bout a little more info on the anti-spark resistor? You said 100 ohm? Is this an off the shelf part that can be bought at Radio Shack? I'm curious because this it the first time I've seen anyone use one to kill the power spark. It's not a big deal on the smaller stuff but I've got a 6s system that makes the guys in the pitts jump when I plug it in.

Greg Covey

Hi,

You can get all the anti-spark details in the Ask AMP'D section of issue 2 of AMP'D called, [link=http://www.rcuniverse.com/magazine/article_display.cfm?article_id=950]Arming the Big Boys[/link].

All my new models (including reviews) that are 6s or higher voltage will have the anti-spark feature added. I buy the 100ohm, 1w resistors on-line at Newark Electronics for 5 cents each and there is no minimum purchase. Radio Shack is another good idea.

Check out my soon be released [link=http://www.rcuniverse.com/magazine/article_display_preview.cfm?article_id=1124]Ultimate 40[/link] review on this preview link. I used a modified MPI Arming Switch and the ESC On/Off switch with my 100ohm resistor on a 6s LiPo. Unlike what Castle Creations says, the spark is not your friend!

Good luck!

Greg Covey

The Nitro kit does come with a nice piece of thick Mylar so I cut it down to 90mm size using the same FSA ratio as in my FlyFly EDFs. I bent the motor wires at a right angle to plug into the CC HV85 ESC without hitting the wall. The wires are also twisted so that they are flat in-line with the Wemotec mounting tab. This allows for an easy slice out of the Mylar to make the exhaust tube fit.

Greg Covey

I used a standard servo for the nose wheel steering.

The Spectrum AR7000 dual receiver was mounted to the side with Velcro. On strong power systems using two packs in series, I use a separate receiver pack (2-cell 1500mAh LiPo) and a Duralite regulator with a fail-safe switch for safety.

Greg Covey

The EDF was mounted to the modified base shown earlier (Post #6) using 4 screws. The CC HV110 ESC was secured to the aluminum tube with two ty-wraps. I then mounted the exhaust tube using Zap-A-Dap-A-Goo II and covered it with duct tape after allowing it to dry overnight.

The tail end of the tube was supported by a custom 1" wide foam wrap I made. It holds the Mylar tube in the center of the opening. Lastly, I used some black trim tape to enhance the look.

gr8taz nitro

My Feedback: (7)

Greg,
Thanks for the info and the link to the article.

Greg Covey

As previously reported by others, the battery (or batteries) need to be placed behind the nose gear servo in between the two air intakes. It seems obvious that the manufacturer had never tested the design with EDF. I have seen this several times before on other designs.

I decided to build a battery box that allowed the packs to easily slide in place and have holes for some cooling. The battery packs will be secured with a Velcro strap across the top. The battery box partially blocks the air intake openings but they seem large enough to make the blockage insignificant.

My CG is set for 7.25".