RE: Turnigy H.A.L. (Heavy Aerial Lift)
Has it flown yet? I'm curious what kind of flight time you can get. I did an analysis based on Newton's momentum theorem and using the energy density of batteries available off the shelf I determined that any electric powered vehicle using vertical thrust to maintain flight can only achieve about 10-15 minutes max flight time. Curious if that was accurate. Looks good, I might have to order one myself to play around with.
Posted on: 8/9/2012 7:29 AM by Author "harralk" in the forum "FPV, UAV''s & Drones"
http://www.rcuniverse.com/forum/fb.asp?m=11186863

RE: Perhaps the dumbest question of the month
That's acutally a very good question, and one that I had when I was first learning to fly. I agree with everyone else here. I've been flying smaller size planes for years and I've never really used the rudder on any of them, except for take-off, landing, and taxiing. You certainly wouldn't want to be in a full-size plane without some rudder input (it gives the awkward sensation of your back-end falling inside the turn and you don't have quite the correct view from the pilot's seat). But as long as you can control the plane alright don't worry about over-complicating things just yet. Practice with it when you get more experience and see what happens. There are some 3D maneuvers that you can only perform with the correct amount of rudder, but they usually require a more advanced plane. The same thing also applies to flaps, should you ever upgrade to a plane that has them. If you can get the landings correct without using the flaps, they aren't really required either. However, I will add that I do prefer having flaps and regularly use the rudder on my larger size planes. Good luck!
Posted on: 8/8/2012 9:05 AM by Author "harralk" in the forum "Beginners"
http://www.rcuniverse.com/forum/fb.asp?m=11185576

RE: First GoPro Flight
I have to say, that is indeed awesome! Great video! I've been looking at Gopro's new wifi transmitter system. I don't suppose you've used that yet or know someone who has?
Posted on: 8/7/2012 7:16 AM by Author "harralk" in the forum "Aerial Photography and Video"
http://www.rcuniverse.com/forum/fb.asp?m=11184125

RE: I could not resist...
in case you didn't know already, you can usually fix the bubbles in the covering. They're usually a result of shipping the wood airframe from one part of the world to another and not necessarily a reflection of the build quality. They can usually be taken out with a little care and a heat gun or iron and a mitt. Looks like a neat plane. Let us know how she flies!
Posted on: 7/24/2012 10:15 AM by Author "harralk" in the forum "Beginners"
http://www.rcuniverse.com/forum/fb.asp?m=11167349

RE: Batman lives!
Awesome footage!! I love watching wingsuit flying. Doubt I'll ever have the nerve to try it. At one point in this video it looks like the red guy brushes against the cliff face.
Posted on: 7/5/2012 7:24 AM by Author "harralk" in the forum "Aerial Photography and Video"
http://www.rcuniverse.com/forum/fb.asp?m=11143769

RE: Hobbico Starter
My assumption is that you indeed have a defective starter. I had that exact starter and engine for my first plane and it turned my .46 LA over JUST FINE on my 12V field battery. In fact, after the engine started running on its own it would slow down slightly when I pulled the starter off. And I certainly couldn't stop the spindle with my bare hands.....there's my two cents.
Posted on: 5/22/2012 1:23 PM by Author "harralk" in the forum "Beginners"
http://www.rcuniverse.com/forum/fb.asp?m=11090737

RE: is this normal? Electric motor mounted to the right
It's called P-factor and yes, it's normal. It's put in there deliberately to compensate for the plane's tendency to yaw to the left when the plane pitches up. There won't be any noticeable effects of it. The rudder trim will take care of it.
Posted on: 5/22/2012 1:09 PM by Author "harralk" in the forum "Beginners"
http://www.rcuniverse.com/forum/fb.asp?m=11090724

RE: I have a HOAYE 4.5
I've never played around with the 4.5" Hoaye, but their 5" unit is ok. If you wanted to sell it they're like $25 new, plus shipping.
Posted on: 3/26/2012 6:59 AM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11015412

RE: Brushless kv ?
the Kv rating for a brushless motor is the rating for "RPM per volt". It's an obscure value used to determine how fast a motor will spin given a particular voltage input. Here's an example: a motor is rated at, let's say, 2000 Kv, and you have a 3S 11.1V battery. That means at full power the motor will spin at 22,200 rpm. The motor controller automatically increases power to the motor to get it to spin at the appropriate speed for any given voltage input. What this means in the real world is that a higher Kv motor will spin faster, but also use more power. Whereas a lower Kv motor will run longer on a charge, but won't move the car as fast. One way to get around this is to use a lower Kv motor with a higher voltage battery. That way you get higher speeds and lower power draws. Hope this helps a little.
Posted on: 2/29/2012 7:14 AM by Author "harralk" in the forum "RC Electric Off-Road Trucks, Buggies, Truggies and more"
http://www.rcuniverse.com/forum/fb.asp?m=10981318

RE: Need Help - Can't Find Right Motor
By my calculations, you should be running a motor with a Kv rating of no more than 2000 with a 6S battery at full power. 2500Kv is too high for that fan at full speed. You could try limiting the throttle to about 80% with the CS480-2500Kv motor, but I don't know how much power you'd get at that point. The problem that I see is you have a 10-blade EDF which while great in theory, requires one hell of a motor to run up to full speed (45,000 rpm as rated by the manufacturer). If the motor is burning up, but not the esc I would say the esc isn't being overloaded. Also, forgive me if it's an obvious question, but what timing is your esc set to? I assume you already set it to high, but maybe double check?
Posted on: 2/27/2012 8:40 AM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10978219

RE: What batteries for 5
My guess is you have either the 7-blade Haoye or 4-blade ChangeSun fan from hobbyking, since I have the same 700Kv motor from them. My input will be for either of these two fans based on my experience. If you have a different fan then this may not apply... Note: with ANY 5" fan, a 12S pack and 700Kv motor should push the fan to its critical speed (roughly 36000 rpm at sea level, lower rpm for higher altitude) so you definately don't want any more battery than that, period!! A safe max speed in order prevent the the rotor tips from going supersonic on any fan at any reasonable altitude will be roughly 30,000 rpm, which with a 700Kv motor means 10S max. However, I've taken both fans to 30k+ rpm and both fans had cracks in the motor mounts after about 5 minutes of sustained 30k+ speed. There are some extraneous conditions surrounding my tests, but for safety I wouldn't suggest maintaining an excess of about 25k rpm sustained speed on either fan. With a 700Kv motor on either fan, 25k rpm means an 8S battery max. My opinion would be to get a 600Kv motor instead on 10S or 480Kv on 12S to lower the amps and protect the esc. My guess is you'll be reaching the threshold for the 100A ESC on 10S with a 700Kv motor if you have the 7-blade fan. The 4-blade fan will probably run around 100A with the 700Kv, but you won't be getting much power out of the fan at that point. That's my two-cents based on my experience. Take my advice at your own discretion.
Posted on: 1/3/2012 8:15 AM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10889354

RE: Where to buy ducted fans
That's the first motor I ordered for the Haoye. The big blue one in my earlier pics. At least that's what I'm assuming he's talking about
Posted on: 9/28/2011 5:38 PM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10739271

RE: Where to buy ducted fans
[quote]ORIGINAL: AmishWarlord harralk, you didn't tell me you ordred one of those! Lets see it! [/quote] I'm sorry, see what?
Posted on: 9/28/2011 4:59 PM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10739203

RE: Where to buy ducted fans
[quote]ORIGINAL: ACES&8s Can the HobbyKing 45-70mm inrunner be worked to set cooling holes into the end caps? [/quote] It's funny you ask that, 'cause I just took my 1200Kv apart (didn't want it eating up any more ESC's). From looking at the way it's assembled internally I would say that you probably could make some air holes in the end caps, but they couldn't be very big on the front side due to the mounting holes. My intent for this motor was to custom make an aluminum heatsink that fit between the motor and the fan and cut some small holes on the inside of the fan to allow the air to get in to the motor. If you'd like I could draw up the dimensions of the motor end caps since I already have mine taken apart.
Posted on: 9/28/2011 4:46 PM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10739179

RE: Where to buy ducted fans
Ran the HET 90mm back on the bench with the10S battery. I only took the throttle up to about 80%, but it still achieved 3.1kg thrust. The current draw must have been getting close to 100A because I could tell the Turnigy 100A ESC was getting pretty warm (didn't want to risk damaging my CC 120A from flying debris). The power meter read ~2500W, but I was too nervous about the running fan to get close enough to read the voltage/amperage. With the proper motor I believe this little fan could produce as much thrust as the ChangeSun. As for the Electrifly motor I had in there, I think it's pretty well toasted. It was smoking when I shut it down. Now if I just hadn't fried one of my 6S batteries testing the Haoye I could throw the ChangeSun back on with 12S and the 550Kv motor that just came in. Of course, if the Haoye hadn't blown apart I could test it with 10S and the 700Kv motor that just came in too. Oh well, I should probably put this project on hold for a while.
Posted on: 9/25/2011 11:30 AM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10733349

RE: Where to buy ducted fans
[quote]ORIGINAL: AmishWarlord I see no other way. Your going to have to go with the 300A [b]FAT BOY[/b] [/quote] I'm starting to think it might be nice to have a BF ESC for bench testing. I shouldn't have to worry about torching that guy. I will need a second 10S battery though to run that thing in parallel... I just want to know why they made such a massive ESC and what type of plane/heli would it be used in except full size?? "Welcome to HobbyKing airlines...."
Posted on: 9/21/2011 5:27 PM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10728015

RE: Where to buy ducted fans
Next I'm thinking of throwing my 90mm HET fan back on the test stand with the 10S battery. With the motor at 1800Kv it should be able to max the little fan out, assuming it doesn't fly apart on me too.
Posted on: 9/21/2011 10:05 AM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10727427

RE: Where to buy ducted fans
Well, I finally managed to kill the Haoye fan. I ran it up on 6 cells and just when I got right around 2-3kg of thrust (not sure exactly because I wasn't looking at the final instant) the center nut came loose on the motor shaft, stressed the center cap which cracked and flew apart, chipping one of the impeller blades. And then my beefed-up Turnigy ESC began spewing red smoke. The wires didn't come unsoldered this time because I soldered on extra wires, it just started smoking internally. The motor housing also cracked in several places. I'm lucky this wasn't any worse than it was, and I'm lucky I wasn't close to it. I'm not sure what rpm it was at when it blew because I haven't gotten a laser tach yet, but based on the Kv of the motor and the approximate throttle position I would guess between 20krpm and 25krpm. The last power reading I saw was around 2000-2500 watts, which on 6S is more than the 100A ESC would be able to handle for very long. Based on what experience I've had running the Haoye I would expect that a 1000Kv motor on 4-5S would just about max it out. 6S running an 880Kv motor would also be at the high end, but the amperage might be higher than the motor can handle. If I was going to try this fan again I would probably run 10-12S on a 300-450Kv motor to keep the amps as low as possible. This fan just gobbles up the power, so get a VERY high amperage ESC with any motor you get.
Posted on: 9/21/2011 9:57 AM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10727420

RE: Where to buy ducted fans
I'm doing some calculations on the data I gathered from my test runs and I found the exit velocity of the air in my 120mm ChangeSun is about 200mph!! That may not be as high as premium EDF units, but that's still pretty impressive.
Posted on: 9/15/2011 7:08 PM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10718617

RE: hobby king
1-800-607-5803 Good luck getting a hold of anybody. I tried for three days and couldn't get anyone, no voicemail pickup either. Try emailing if no one answers: support@hobbyking.zendesk.com They replied back to my email within a few hours.
Posted on: 9/15/2011 1:49 PM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10718231

RE: Where to buy ducted fans
[quote]ORIGINAL: AmishWarlord Well hopefully Hobby King will get that $300 turbine up soon so we can't stop screwing around with the EDFs and get some real fires and explosions going. [/quote] yea buddy!! But seriously, it's scary to even think about it. You know they're working on it, though.
Posted on: 9/14/2011 4:38 PM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10716881

RE: Where to buy ducted fans
Ok, I figured out how to adjust the motor settings on the CC data viewer. Now the data shows actual shaft rpm for an 8 pole motor (at least I think this motor is 8 pole). Corrected performance stat's: 9 lbs thrust @ 30,400RPM, 37.8V, 74.1A, 2803W I think this is slightly more accurate than what I originally posted.
Posted on: 9/12/2011 9:17 AM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10712838

RE: Where to buy ducted fans
[quote]ORIGINAL: AmishWarlord Here is a pic of the back of a 125A Red Brick at HK. [/quote] That is just absolutely frightening. My CC 120A has 8 AWG battery wires!! Like I said a while back, this wouldn't have happened if these were American made, right? Too bad we can't issue a public service announcement about this. The only thing that puzzles me is I've seen others run this exact setup without issue or mention of changing the wires. The wires may not be the only issue, but I don't like the 12 AWG on there at all. As an aside, I've been waiting for the people in my house to leave for a few minutes so I can power up the Haoye fan. Everything's ready to go, just waiting for the right time to make a lot of noise. Stay tuned...
Posted on: 9/10/2011 4:42 PM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10710534

RE: Where to buy ducted fans
After careful analysis and a consultation with my electrical engineering friends, I think I figured out why the Turnigy ESC's keep catching on fire. The battery wires are only 12 AWG and should be 10 AWG minimum. From investigating the carnage and the video footage the wires are heating up and de-soldering themselves, then arcing to the ESC which in turn produces a fire. I'm going to attempt one more run with a new 100A Turnigy Super Brain ESC and replace the battery wires with larger diameter if needed.
Posted on: 9/10/2011 3:18 PM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10710435

RE: Where to buy ducted fans
[quote]ORIGINAL: AmishWarlord I think your 121,000 number is magnetic pole hits per minute rather than RPM. [/quote] That makes sense. That means it's turning closer to 15,000rpm at full throttle. That's not too bad. And with the motor rated at 880kV, that means it's seeing roughly 17V, rather than the 33V I thought I was feeding it.....well within the specificated voltage limit.
Posted on: 9/9/2011 9:38 AM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10708771

RE: Where to buy ducted fans
Official test data for the 120mm ChangeSun EDF: (drum roll please) Max thrust - 8.5 lbs (3.9kg) @ 76.6A, 37.6V, 2912W, 28,700rpm This was downloaded from the CC ESC. The rpm reading from the ESC said 121,000 rpm, which is a load of crap. Not sure why the reading is off, but I verified with my trusty ol' tach and flashlight and it only goes up to four digits (won't read above 9,999). So I ran to the LHS and picked up a new ol' trusty tach. The thrust measurement is quite a bit less than others have seen with this setup, but that's probably due to my altitude here. At 5,500 feet the air gets a lot thinner. Also why the amperage is a lot lower and the RPM a lot higher. This is why I went through all this trouble. I needed to verify max thrust at this altitude (I could reference the time and date with the local weather station, get the barometric pressure for today and use it to calculate the air density. Could be helpful.....). Now I can proceed with the little mods I want to make to this EDF in order to make it more suited to my application. I'm thinking improve motor cooling, tail cone for the motor, scalloped edges of the rear of the EDF to make it quieter. Maybe I'll start a new thread for the mods to the EDF.... Now that I have an ESC that won't catch on fire, does anybody want me to put the Haoye back on and check it out? Not really interested in doing it unless somebody wants the info.
Posted on: 9/8/2011 12:53 PM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10707493

RE: Where to buy ducted fans
Now I'm really P.O.'d. I'm running the exact same setup as I've seen others run and I'm still burning up my ESC. Out of desparation I went to my LHS and picked up a Castle ICE 120HV just to rule out the ESC. I need to get this thing working, dammit. In the mean time, does anybody know why an ESC would just burn up, if I'm not running excessive current through it?
Posted on: 9/8/2011 9:59 AM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10707274

RE: Where to buy ducted fans
[quote]ORIGINAL: AmishWarlord Have you seen these Taiwan fans? [/quote] They look nice and they aren't too expensive by themselves, but the real trick to them I think is the motor, which is more expensive than I'd like. Update: I took the collet for my ChangeSun fan into the shop today and drilled a new hole so now it's centered, balanced, and ready to go. I tried a test today and the motor started cutting out just above half throttle. It was intermittent, but enough to make me want to stop for now. I'll charge the battery back up and try again after I get some hearing protection. I may have made myself a little gun-shy with all those exploding ESC's. I'll work past it once I'm confident it won't start shooting sparks or fly apart on me. NERVES BE DAMNED, WE HAVE DATA TO COLLECT!!
Posted on: 9/7/2011 5:15 PM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10706294

RE: Where to buy ducted fans
Nothing catastrophic to report about the first power-up. I only went to about 30% throttle just to be safe. But even at that speed I couldn't detect any heat from the ESC. The center hole in the collet is off-center which caused the impeller to rub against the case a little bit. It didn't rub when I turned it by hand, only at speed. I'll have to make a trip to the machine shop on campus this week to bore out the smallest of the three provided collets. I took the impeller off and stuck it on the balancer and oddly enough the side that rubbed isn't the lightest as I would have expected. Looks like I have some work ahead of me. I will mention the ChangeSun if definately designed for an outrunner motor. If you look closely at the front of it with the motor mounted, the impeller doesn't completely cover up the front of the motor, suggesting they designed it for airflow.
Posted on: 9/4/2011 8:50 AM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10700884

RE: Where to buy ducted fans
Just got my ChangeSun EDF, T600-880kV motor, and 100A HV ESC in the mail (took a whole week, the HK guys are slipping). Got it assembled, the test rig modified for the new fan, and the battery is charging up as I type.....ooh, I hear the charger's done......hold on....
Posted on: 9/3/2011 3:49 PM by Author "harralk" in the forum "Electric RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10699994