RE: What prop do i need?
Free plans for the 3DX foamie, a 3D Aerobatic Park Flyer: http://www.foamyfactory.com/airplanes.htm Scroll about two-thirds of the way down the page. Links to dozens of free foamie plans: http://www.rcgroups.com/forums/showthread.php?t=851608 If you search the web, you can find hundreds more free foamie plans. Good luck! - Jeff
Posted on: 11/17/2009 5:32 PM by Author "jdetray" in the forum "Brushed/Brushless motors, speed controls, gear drives"
http://www.rcuniverse.com/forum/fb.asp?m=9260853

RE: Recommend a battery for this motor/esc combo???
Don't thank me! Thank Phil (Dr. Kiwi), who has tested more electric motors and props than just about anyone. [b]Formula for Run Time[/b] run time in minutes = (Battery Capacity in Ah/Motor Current in A) x 60 So for a 1250 mAh battery and an average current of 10A: 1.250/10 x 60 = 7.5 minutes It's a rough calculation, but it gives you a ball park figure. - Jeff
Posted on: 11/16/2009 4:42 PM by Author "jdetray" in the forum "Electric Training"
http://www.rcuniverse.com/forum/fb.asp?m=9258304

RE: Recommend a battery for this motor/esc combo???
Mike - You may be interested in Dr. Kiwi's test results for this motor with a wide variety of props, found in this thread: [link=http://www.rcgroups.com/forums/showthread.php?t=610852]Ultrafly Frio E/10/10[/link] Suffice it to say that with too large a prop, you may exceed 12A with 3S. However, there are some good-performing props that keep the current well below 12A. All the details are in the thread. - Jeff
Posted on: 11/16/2009 3:09 PM by Author "jdetray" in the forum "Electric Training"
http://www.rcuniverse.com/forum/fb.asp?m=9258098

RE: What prop do i need?
Exceed sells three different Alpha 370 motors: 1080kV, 1200 kV, and 1360 kV. Which one do you have? - Jeff
Posted on: 11/14/2009 1:50 AM by Author "jdetray" in the forum "Brushed/Brushless motors, speed controls, gear drives"
http://www.rcuniverse.com/forum/fb.asp?m=9252583

RE: What prop do i need?
Exceed makes many different brushless motors. Which one do you have? - Jeff
Posted on: 11/13/2009 6:50 PM by Author "jdetray" in the forum "Brushed/Brushless motors, speed controls, gear drives"
http://www.rcuniverse.com/forum/fb.asp?m=9251823

RE: Watt Meter - Which one to buy ?
[quote]ORIGINAL: BalsaBob One last (stupid) question. Is this (the Watts Up) something that stays in the plane temporarily during a flight so that the readings can be obtained ? Do the people that have the big/large/hi-amp planes generally keep one in the airplane at all times so that they can check the data/info from it after a flight ? Thanks again. Bob [/quote] There is no such thing as a stupid question, Bob! I don't know of anyone who keeps a Watt's Up type meter in the plane. Normally, it is used only for testing on the ground when setting up your plane (choosing a prop, choosing a battery, etc.). The inexpensive wattmeters such as the Watt's Up do not store their readings, so there would be no point in carrying the meter during a flight, anyway. There are systems that are designed to be flown, however. One maker of such products is [link=http://www.eagletreesystems.com/]Eagle Tree Systems[/link]. For starters, get a good basic wattmeter like a Watt's Up, Medusa, or AstroFlight. Any of them will help you avoid frying expensive motors, ESCs, and batteries. - Jeff
Posted on: 11/2/2009 11:00 PM by Author "jdetray" in the forum "Electric General Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=9224036

RE: Go Brushless.com
[quote]I am doing two motors. If I do the same number of turns on each motor, do you think they'll be pretty close in kv and power? One goes to each wheel so it's pretty important.[/quote] All you can do is try your best to wind each motor with exactly the same number of turns and pack the wire as tightly as possible on both motors. If you do that, they ought to be very close in performance. - Jeff
Posted on: 10/25/2009 7:14 PM by Author "jdetray" in the forum "Brushed/Brushless motors, speed controls, gear drives"
http://www.rcuniverse.com/forum/fb.asp?m=9201418

RE: Go Brushless.com
I've used the Radio Shack wire myself. I think the insulation is a bit thinner than on the GB Newbie wire, but otherwise it seems OK. You are limited to 22, 26, and 30 gauge in their 3-pack. Thinner insulation means you must be more careful not to short out the windings when bending the wire across sharp edges on the stator. To remove the insulation, I scrape with an Xacto knife, sometimes cleaning up with very fine sandpaper. You can also use an aspirin tablet and a soldering iron to remove the insulation (Google for the actual technique). The fumes are dangerous, however. - Jeff
Posted on: 10/25/2009 3:07 PM by Author "jdetray" in the forum "Brushed/Brushless motors, speed controls, gear drives"
http://www.rcuniverse.com/forum/fb.asp?m=9200921

RE: Go Brushless.com
As much as I like the folks at GoBrushless.com, it's not the only source for wire. For example, Don Armstrong at Strong RC Motors sells many gauges in small quantities: http://www.strongrcmotors.com/Wire.htm There are plenty of other places to purchase wire. Do a search for [b]magnet wire[/b]. You could go to #24 wire and still terminate as star. You might be able to get a few more turns with this gauge, further reducing the kV, which is one of your goals. You are always better off using the largest wire you can to accomplish your performance goal. To quote from Ron's post: "more/thicker copper in the slot: -> lower copperwire resistance -> higher efficiency -> higher power/weight ratio and/or lower temperature." Winding with small wire may be easier on your fingers, but in this case, the larger wire is preferred. - Jeff
Posted on: 10/25/2009 12:48 PM by Author "jdetray" in the forum "Brushed/Brushless motors, speed controls, gear drives"
http://www.rcuniverse.com/forum/fb.asp?m=9200684

RE: Go Brushless.com
Just a few random thoughts. Hopefully Ron will check and confirm the accuracy of my statements. (It's been a while since I last constructed a motor.) That motor appears to have a Delta wind. Pairs of wires are connected together and go to the speed controller. In a star (also known a Wye) termination, a single wire from each phase goes to the controller. Rewinding with the same gauge wire and the same number of turns but using a star termination will lower kV by a factor of 1.73. Since you plan to rewind the motor anyway, you can count the number of turns as you remove the old wire. To determine the wire gauge of the existing windngs, obtain (buy or borrow) a caliper to measure the diameter of the wire. There are plenty of sites on the web that list the diameter for any gauge of wire. Here's one: http://www.powerstream.com/Wire_Size.htm And here's an good site that summarizes all of these topics: http://www.bavaria-direct.co.za/models/motor_info.htm To keep it simple, I'd probably use the same gauge wire and the same number of turns as the original but use a star termination instead of Delta. This will lower your kV by a factor of 1.73 and give you more torque at the expense of lower top speed. - Jeff
Posted on: 10/25/2009 12:19 PM by Author "jdetray" in the forum "Brushed/Brushless motors, speed controls, gear drives"
http://www.rcuniverse.com/forum/fb.asp?m=9200605

RE: ParkZone chargers and batteries, are they quality?
[quote]ORIGINAL: twoslick2 Can anybody reccomend a charger I can get that would work with my Rhino 610 mAh, 20c 2s, 7.4v LiPo batts? Thanks! [/quote] I would think that practically any lipo charger ever made would be able to charge that battery. - Jeff
Posted on: 10/25/2009 11:40 AM by Author "jdetray" in the forum "Electric Training"
http://www.rcuniverse.com/forum/fb.asp?m=9200529

RE: Go Brushless.com
[quote]ORIGINAL: Metallover Old thread here, but how much wire comes on the small and 1/4lb spools? How many cd-rom motors can you get out of a small spool? [/quote] The GoBrushless.com site lists the amount of wire on each spool, and it depends on the gauge of the wire. The length of wire required for a motor depends on the size of the wire, the thickness of your stator, and the number of turns. You should be able to build 5 single-stator CD-ROM type motors from one small spool of Newbie wire. This assumes you'll be using a 9-pole, 17, 20, or 22.7mm stator. If you have not wound a motor before, I strongly recommend getting three small spools (one of each color), so you can use a separate color for each phase. If you get three small spools, you'll have enough wire for approximately 15 single-stator CD-ROM type motors (or 7 double-stator motors, or 3-4 triple-stator motors). Building your own motors is a lot of fun, in my opinion. Nowadays, you won't save any money, but you'll learn a whole lot about brushless motors. - Jeff And HELLO to Ron!
Posted on: 10/25/2009 2:31 AM by Author "jdetray" in the forum "Brushed/Brushless motors, speed controls, gear drives"
http://www.rcuniverse.com/forum/fb.asp?m=9199978

RE: ParkZone chargers and batteries, are they quality?
Hi Chris - I don't know anything, good or bad, about the ParkZone batteries and chargers. However, when a lipo puffs, it usually means it has been asked to provide too much current. When you attempt to draw more current from a battery than it can safely provide, battery failure is a common result. That's when puffing can occur. If you can provide more details (capacity and "C" ratings of the batteries that failed and current being drawn by the power system), it would help us figure out what happened. If you don't know the current, then provide as much info as you can about the motors and props of the plane(s) whose batteries puffed. - Jeff
Posted on: 10/25/2009 1:52 AM by Author "jdetray" in the forum "Electric Training"
http://www.rcuniverse.com/forum/fb.asp?m=9199943

RE: Max Battery
What aspect of using a higher capacity battery concerns you? As long as the higher capacity battery fits, and as long as its greater weight doesn't hurt performance too much, it should work fine. If it's the weight that concerns you, find out the weight of your proposed larger battery and add some weight to your current setup to see how the heli performs with the additional weight. - Jeff
Posted on: 10/18/2009 9:00 PM by Author "jdetray" in the forum "Electric General Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=9183811

RE: turning off led circuit with servo signal
Richard - You might want to post your question [link=http://www.rcgroups.com/diy-electronics-199/][b]here[/b][/link]. - Jeff
Posted on: 10/15/2009 4:56 PM by Author "jdetray" in the forum "Electric General Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=9176004

RE: PC power supply?
More links ... Here are a few discussion forum threads on the topic of converting PC power supplies for use as 12V bench supplies for chargers and other equipment: [url]http://www.rcgroups.com/forums/showthread.php?t=368639[/url] [url]http://www.rcgroups.com/forums/showthread.php?t=315179[/url] [url]http://www.rcgroups.com/forums/showthread.php?threadid=55555[/url] [url]http://www.rcgroups.com/forums/showthread.php?threadid=114054[/url] [url]http://www.rcgroups.com/forums/showthread.php?threadid=41161[/url] In addition, here are some helpful web sites on the same topic: [url]http://web2.murraystate.edu/andy.batts/ps/powersupply.htm[/url] [url]http://web2.murraystate.edu/andy.batts/ps/DESIGN_GUIDE.HTM[/url] [url]http://www.marcee.org/Articles/PCPowerSupply.htm[/url] [url]http://www.dream-models.com/eco/DIY-powerSupply.html[/url] [url]http://www.extensiontech.net/articles/howto/jb/pstu/[/url] [url]http://reckerclub.tripod.com/id105.html[/url] [url]http://homepage.ntlworld.com/fast.electrics/PSU.pdf[/url] [url]http://www.nfdc.net/home/cbdb/Teardrop%2012%20V%20Power%20Supply.htm[/url] - Jeff
Posted on: 10/15/2009 4:51 PM by Author "jdetray" in the forum "Electric General Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=9175989

RE: C rate
To make practical use of the "C" rating, you first must know the maximum current (Amps) drawn by your power system. This is best found by measuring with a wattmeter, but you can also use information provided by motor vendors who often state how much current the motor will draw with certain props. Let's say your power system draws 25A. That means you need a battery that can deliver at least 25A. You can use "C" ratings to determine if a particular battery is up to the job. Suppose you have a 2000 mAh battery with a "C" rating of 10. Multiply the battery capacity (converted to Amp-hours) by its "C" rating: 2000 mAh = 2.0 Ah 2.0 x 10 = 20A So 20A is the maximum current this battery can provide. Therefore, this battery is not suitable for powering a plane that needs 25A. Now let's suppose you have another battery that also has a capacity of 2000 mAh but with a "C" rating of 20. 2000 mAh = 2.0 Ah 2.0 x 20 = 40A This battery can provide up to 40A, which is more than enough to power a plane requiring 25A. The point is that both are 2000 mAh batteries, but one is capable of powering a 25A system and the other is not. The "C" rating helps you determine if a given battery can handle a given power system. In the real world, many battery makers overstate the "C" ratings of their batteries by testing them under ideal conditions. So it's probably a good idea to discount the claimed "C" ratings somewhat. In other words, select a battery whose claimed "C" rating is 20-30% greater than your calculations suggest you should need. - Jeff
Posted on: 10/15/2009 4:42 PM by Author "jdetray" in the forum "Electric General Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=9175969

RE: brushless motor and stick motor mount
Stick mounts are available for many brushless outrunners. Check this [link=http://www.google.com/search?hl=en&source=hp&q=outrunner+stick+mount&aq=0&oq=outrunner+stick+&aqi=g1g-m1]Google search[/link]. - Jeff
Posted on: 9/28/2009 12:27 PM by Author "jdetray" in the forum "Brushed/Brushless motors, speed controls, gear drives"
http://www.rcuniverse.com/forum/fb.asp?m=9130008

RE: How to hook up my ESC to my brushless motor?
Hi Andy - If you use the $3 wattmeter setup, you can still use the meter for other purposes. Unplug the connectors for the R/C battery and plug in the meter's regular test leads, and you can use the meter for conventional purposes. However, if you get one of those very inexpensive meters, the cost is so low that it makes sense to dedicate it to R/C usage. That way, it's always ready to go for R/C use. In the long run, I think you will be much happier with a purpose-built R/C wattmeter that displays both current and voltage at the same time. Something like the [link=http://www.bphobbies.com/view.asp?id=A0320107&pid=U054250&img=l]Watt's Up meter[/link] is what you want. There are many brands available; I posted the Watt's Up link only because it includes a nice photo of the meter's display. Having used both the $3 solution and a purpose-built wattmeter, I much prefer the purpose-built wattmeter. - Jeff
Posted on: 9/14/2009 10:48 PM by Author "jdetray" in the forum "Brushed/Brushless motors, speed controls, gear drives"
http://www.rcuniverse.com/forum/fb.asp?m=9096330

RE: Whart discharge rate battery?
To keep the calculations simple, let's assume you prop your motor to draw 30A. The first question is: What battery capacity will you need for decent flight times? Let's say you want a flight time of 8 minutes. The formula for that calculation is: Run time in minutes/60 x Motor current in A = Battery capacity in Ah Or in this case: 8/60 x 30 = 4 Ah = 4000 mAh So for an 8-minute flight, you'd want a 4000 mAh (or greater) battery pack. Now, you need to determine the required "C" rating of the battery pack. We know we need a pack capable of providing at least 30A. To give the power system a good safety margin - and because battery makers often overstate the "C" ratings of their packs - lets go for a battery pack that can deliver 45A. The formula: Motor current/battery capacity = C rating Or in this case: 45A/4Ah = 11.25 "C" rating So a 4000 mAh, 11.25C pack would be suitable. Since 20C batteries are readily available, I'd go for a 4000 mAh, 20C pack. These are very rough calculations and do not take into account the type of plane, your flying style, etc. But it's a starting point. You absolutely will want to use a wattmeter to check the actual current draw. And I would not use a 30A ESC if you are planning to draw 30A. Go for an ESC with a current rating that is higher than you expect to draw to give the ESC a margin of safety. A 40A ESC would be a good choice for a 30A power system. - Jeff
Posted on: 9/14/2009 4:19 PM by Author "jdetray" in the forum "E-Flight Power Sources"
http://www.rcuniverse.com/forum/fb.asp?m=9095239

RE: Flying W or CapricornV2.0
Here you go. [link=http://www.wattflyer.com/forums/showthread.php?t=26120]Capricorn - the ultimate flying boat.[/link] and [link=http://www.rcgroups.com/forums/showthread.php?t=898958]The Capricorn is a great trainer, nightflyer, seaplane[/link] - Jeff
Posted on: 9/11/2009 11:15 PM by Author "jdetray" in the forum "Electric General Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=9088416

RE: COG
I know what gb is trying to say. But actually, balancing the plane on two pencils as described in the first post DOES tell you where its Center of Gravity (COG) is. The balance point IS the COG. However, without previous knowledge of where the COG [i]should[/i] be located, knowing where it is currently does not help you much. You'll have to depend on a glide test or on the experience of other pilots with similar planes. If you built the plane from plans, the plans should provide some indication of where the COG should be. I'll bet if you post a picture of the plane or at least a more detailed description, someone will know approximately where the COG should be. - Jeff
Posted on: 9/10/2009 1:09 AM by Author "jdetray" in the forum "Foamies! - RC Electric Foam Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=9083399

RE: PRECISION AEROBATICS ADDICTION
You might want to check out [link=http://www.rcgroups.com/forums/showthread.php?t=721432][b]this gigantic thread[/b][/link] devoted to the Addiction. I'll bet you could get some good advice there. Or you could contact the manufacturer for advice: http://www.addiction3d.com/contact.html Is it possible to move any of the servos forward? - Jeff
Posted on: 9/9/2009 12:35 AM by Author "jdetray" in the forum "Electric Training"
http://www.rcuniverse.com/forum/fb.asp?m=9080664

RE: PRECISION AEROBATICS ADDICTION
Could you describe what sort of trouble you are having? From looking at photos of the plane, I don't see why using the wingtips would be a problem. If you prefer to balance at the fuselage, simply stretch a straightedge (or even a piece of string) from wingtip to wingtip and note where the straightedge crosses the fuselage. That's your balance point at the fuselage. And if possible. please write your messages without using ALL CAPS. - Jeff
Posted on: 9/7/2009 11:44 PM by Author "jdetray" in the forum "Electric Training"
http://www.rcuniverse.com/forum/fb.asp?m=9077728

RE: Battery Help
For a 3700 mAh pack, a 1C charge rate is 3700 mA = 3.7 A. A 2C charge rate is twice as much: 7400 mA = 7.4 A. For any battery, just look at the capacity (mAh). A 1C charge rate will always equal that number expressed as mA. A 2C charge rate will be twice that number, expressed as mA. It's nearly always OK to charge a lipo at 1C. Charge at a rate higher than 1C only if the manufacturer says it is OK to do so. No harm will come from charger at a lower rate, but the charge will take longer. - Jeff
Posted on: 9/6/2009 9:48 PM by Author "jdetray" in the forum "Electric Training"
http://www.rcuniverse.com/forum/fb.asp?m=9074820

RE: Can anyone help please?
Hi Matt - For helicopter problems, you might get more help if you post in the [link=http://www.rcuniverse.com/forum/Electric_RC_Helis/forumid_167/tt.htm]Electric Helicopter section[/link] of RC Universe: (jzrf6c: The Blue Ray 450 is a helicopter, not a motor.) - Jeff
Posted on: 9/6/2009 9:38 PM by Author "jdetray" in the forum "Electric General Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=9074795

RE: Profile Foamie
Check the following thread for tons of foamie plans: [link=http://www.rcgroups.com/forums/showthread.php?t=851608][b]Plans For Scratchbuilt Foamies[/b][/link] The inexpensive foam that many people are using is Dow Protection Board III, which comes in large fanfold bundles and can be purchased in the insulation department of many home centers and lumber yards. Availability is dependent on where you are located; fanfold foam is difficult to find in some areas of the U.S. Below are photos of a bundle of an earlier Dow product, but Protection Board looks pretty much the same. Protection Board is used as insulation under house siding. Each of the panels in the photos is 2' x 4' and a full bundle contains 25 panels. - Jeff
Posted on: 9/5/2009 12:04 AM by Author "jdetray" in the forum "Foamies! - RC Electric Foam Aircraft"
http://www.rcuniverse.com/forum/fb.asp?m=9070886

RE: 25Amp Power supply problem
An honest-to-goodness regulated power supply should not do what you are describing. If the voltage is varying that much, then either it's not a regulated supply or it is defective. Most chargers require a regulated supply. Are these power supplies originally intended for use in some piece of electronics equipment? Power supplies that are built for a particular purpose (and a particular load) sometimes don't work well as general-purpose power supplies. They only work properly with the load for which they are designed. An example is certain types of personal computer power supplies which require a load on their 5V line in order for the 12V line to provide the proper voltage. - Jeff
Posted on: 8/31/2009 11:13 PM by Author "jdetray" in the forum "Electric General Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=9060607

RE: Monocote covering help?
I suggest you read the instructions on the MonoKote web site: http://www.monokote.com/monoinst1.html The iron is used to activate the adhesive backing to make the MonoKote stick to the plane and to itself. Then to remove wrinkles and shrink the covering tight, Top-Flite (the maker of MonoKote) recommends a heat gun, though it can also be done with the iron. - Jeff
Posted on: 8/25/2009 12:27 AM by Author "jdetray" in the forum "Electric General Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=9042580

RE: Nitro flyer new to electric and lost!!
Hi Jon, Welcome to the world of e-flight! As for your problem: Your prop is too big! If you look at the [link=http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5655&Product_Name=TR_28-26_1650Kv_Brushless_Outrunner]specs for your motor on the Hobby City site[/link], you will see: [b]Model: TR28-26-1650[/b] Kv: 1650 Voltage: 6~12v Thrust: 200~500g Weight: 45g Shaft: 3.17mm Length: 27mm ESC Required: 18A [color=#CC0000]Suggested Prop: 2cell:8x4 / [b]3cell:7x4[/b][/color] Power: 140W You'll note in red above that the recommended prop when using a 3-cell lipo is a 7x4. Nothing will cook an electric motor faster than running a prop that is too large. My first bit of advice would be to follow the manufacturer's recommendation for the prop. My second bit of advice is to get a wattmeter. My third bit of advice is also to get a wattmeter. (Yes, it's important enough to be listed twice.) Use of a wattmeter to check the current being drawn by your power system is especially important when you are trying props that are different from those recommended by the manufacturer. There are plenty of folks here who can help you learn how to use your wattmeter and interpret the measurements. For some excellent reading, check out [link=http://www.rcuniverse.com/forum/m_7100376/tm.htm]EVERYTHING YOU WANT TO KNOW ABOUT ELECTRIC FLIGHT[/link]. There is a lot to learn, but you can get all the help you need in this forum. For now, get the recommended prop and see if that helps. - Jeff
Posted on: 8/22/2009 7:07 PM by Author "jdetray" in the forum "Electric General Discussion"
http://www.rcuniverse.com/forum/fb.asp?m=9036366