Why do larger motors still turn the same size props as the smaller motors. I thought going from a HL 400 xt turning a 10x4.7 to a eflite 450 I could step up to a bigger prop but I am finding that the 450 turns the same size 10x4.7. I used a APC 11x5.5 E and couldnt tell the difference in verticle. I am a little upset that I spent $65 and the plane flys the same. The 450 weighs 1oz more so it helps with balance as I had the Batt as far forward as possible but I want some extreme verticle. The plane is the HL Extra 330 EP at 15.5oz. I dont have the experiance in electrics yet obviously but I figured stepping up motors is the same in electric as glow. I am using an eflite 20 amp esc and a TP 1320 3 cell. The 450 is not any stronger than my 400xt-explain.

I find that the numbers (400, 450, etc.) are more marketing than real world....

you need to look at the Kv, amps, watts. etc that a motor can handle
at 890kv, that is prety low for the 450...

so to say that the 450 is more powerful than the 400 (while logical) is comparing apples and oranges.......
the numbers mean little....

for a 15oz plane....something like the Hacker A20 would be excellent.....

I am finding that out, the 450 is suposed to 3D up to 25oz. Are the slow flyer props more for 3D than say the Electric labled props?

My 400xt is suposed to 3D models up to 15oz with a 10x3.8 or 10x4.7. The 450 is suposed to 3D up to 25oz with the same props. In order to do that wouldnt the motor need to have higher RPM given the same load to 3D a heavyer plane? Why dont electric motors have rpm ratings with various prop sizes and pitches? I guess I still dont understand watts as a power rating. I know more means more power, but I need to know how the power is delivered and how I can use it.

This is why I thaought I was going to be able to swing a bigger prop because the 450 has such a low Kv at 890, I thought it had more torque and thus could swing a bigger prop at a faster or same RPM and deliver more thrust. What am I missing?

Going from a YS .91 to a YS 1.20 makes perfectly good sense to me. I would never swing the same prop on both engines. 16X4 on the .91 and 17X6 on the 1.20 both at about 9,000 rpm.

I dont have a watt meter the LHS was out, so I am going to do rpm testing.

Use a SF prop. The E props I've found are really only good with more than 300 watts for 3D planes. E props are designed for more speed and less thrust. SF is made for thrust. Watts is basically a measure of how powerful a motor is. The bigger the prop the more amps a motor will pull and the more watts it will produce. A bigger motor can handle heavier amp loads, and therefore pull more watts.

Another thing you must remember, is that even though the 400 and 450 could have the exact same recommended props and the 450 had less Kv, the 450 would still be more powerful because it can spin that size of a propeller easier and faster with less RPM drop under load than the 400.

Big Barry,

Yeah, it's quite a mess at first.

I recommend you invest in MotoCalc8...

You can pick the motor (or add one based on it's ratings), select a prop or range of props, battery, esc, etc and even put in information about your airframe and it will do a pretty amazing job at telling you where you'll be at.

Without the calc, start with watts. For good 3D performance you want a good bit over 100 watts per lb. 150 is really a good starting point and quite doable.

A 16 oz plane is.... well.. one pound... so you want to shoot for 150+ watts... but you have to find a motor that will put that out at 10 volt (about what a fully charged 3 cell lipoly drops to under current draw within it's limits... higher than that and it will drop even lower as well as potentially damage you lipolies.

One motor that will do very well is the Hacker A20-22L (I would think you could use your same ESC with it as the Hacker ESC is 20 amp as well)... fairly lightweight at 2.1 oz and powerful. It will draw about 18 amps at full throttle and a 10x4.7 prop. Your abttery plays a part in this as again, some will drop more than others when being drawn from... the higher the draw, the lower the voltage... the lower the voltage, the less RPM.

If your 1320's are the Gen 1 pack, then they are good for 10-12C... or 13.2 to 15.9 amps... but we're drawing 18... we'll we're pushing the pack anyway. As hopefully you stay less than full throttle most the time and only burst for less than 15 seconds at full. The newer 1320's are rated at 15c or 19.8 amps... perfect for this setup.

Wecalced the Park 450 Outrunner and it too should do about the same. It will draw upwards of 17-18 amp with a 12x6... and that may be your problem... try a 12x6 prop. Another issue might be the packs... they may indeed be somewhat damaged and dropping significantly under draw.

The Hacker measures out to 160 watts on my wattmeter... or 160 watts per lb. Very nice. But then again, so should that 450.

Another motor I am picking up tomorrow is the HiMax 2816-0890... it too calcs out to 150+ watts with a 12x6 on 3cell. It weighs about .6 oz heavier than the Hacker and runs about the same price... $70 or so. Why would I try it? Because I want to compare them and what MotoCalc says.

HiMax motor manuals offer some real good info... see the attached. You scan across the bottom till you find the voltage you put out (10 with 3 cell) and go up till you cross the dotted lines that represent the props sizes. Then stop at the one that crosses the 10 volt line last. In this case it's the 11x4.7 at about 15.3 amps.

Watts is calculated by multiplying volts and amps 10 volts time 15.3amps = 153 watts... very good for a 1lb plane.

If you had a What's up wattmeter [link=http://www.rc-electronics-usa.com/ammeters/dc-amp-meter.html]FOUND HERE[/link] you can hook it up inline between the ESC and battery and it will tell you what amps you are drawing at full throttle and what the voltage drops to, and then it does theclac for you and tells you the watts. This will tell you if your battery or something else is awry.

If nothing else, the $60 for the wattmeter will save you money in batteries and make you better informed as to what prop to use to get the most amps within the motors/batteries capabilites to produce the best watts at 10volts. Remeber, the motors above are 200 watt motors but are putting out 150-160 watts but usually require 4 cells and a smaller prop to generate that... say 14 volts on the chart and a 9x4.7 will draw about 15 amp and give you 210 watts.

But then your weight goes up by one cell and prop goes down a good bit... so 3cell is the sweet spot for most of the smaller 3D planes.

Interestingly, look at the chart on 2 cells or 7 volt... take it up to a 12x6 prop at about 15.75 amps you get about 105 watts... nice for sport flying and can hover a little at first. You dropped one cell, lost only 1/10 of your weight but lost about 1/3 watts. There are a few motors out there that are optimized for 2 cells but it really takes a pefect setup to enjoy them... the Little Screamer Purple Peril comes to mind.

Anywho... information overload.

In closing... your 450 SHOULD fly that 1 lb plane very well... btu if the batteries are weak they may be the limiting factor and cheat the 400 and 450 similarly. Again if you had a wattmeter, you'd know... and you could swap the battery out with nother and see what it's voltage dropped to...

hope this helps some.

I meant to add that you can see a Hacker A20-22L on a 16.85 oz AirfoilZ Yak 54 with a wingspan of 40".

I flew mine and made a video for their website... please look at the power and not my flying... I kinda suck...

http://www.airfoilz.com

then click on the videos button...

It rockets out of a hover and that's a Gen1 1320, Hacker A20-22L and Hacker ESC with an APC 10x4.7 slowflyer... It levels out at 17 amp at full throttle and drops to like 9.8 volts... 166.6 watts.

Maudib

Thanks, that was really helpful. I learned more from reading your post than I have from any other source. I like your idea for a building series of dvds. I know from reading these posts you could make a small fortune by doing an in depth electric video.

I figured out one of my problems. I thought that Eflite was refering to APC E props when in fact they were suggesting their own Eflite Slow Flyer E props. I took off the APC 11x5.5 E prop and switched it out with an APC 10x4.7 SF it does make a difference. I am still baffled though, I took some rpm readings in the garage and the 400xt turns an APC 10x3.8 SF at 6400 rpm and the 450 turned an APC 10x4.7 SF at 6300 rpm this is a $29 motor vs a $65 motor and so far the value goes to the $29 motor. I know that I need to get a watt meter and get all scientific and mathmatical, but for me the magic is in the flying. I had my lhs order Eflite's watt meter. I think you are right and I might have some worn out lipos. I thought lipos were supposed to last along time. I started flying electrics about a year ago and I purchased 3ea TP 1320 3 cells at the same time or with in about a month, I dont know how many flights I put on them all but I went through 5 planes and now am on my 6th. Some days I would get about three flights per pack with charging between flights on each lipo. I should have paid more attention to this stuff in the begining but over the last year I just kept buying planes that were the same weight and size so that I didnt have to spend any more money on gear. I actually have two sets of the same gear so that I could always have a plane ready to fly. My current plane is about 5oz heavier than what I usually fly so that was the reason why I wanted to get a bigger motor.

Thanks again, cant wait to get the watt meter and start learning how to really use these toys.

iirc, 450 is 900 some KV? you can definitely run a larger prop... I ran a 12x3.8 on my A20-20L... the 450 is bigger and has lower kv...

Maybe those old batteries are limiting your results also?? Could be thats all the batts can put out.

Big larry,

You are wielcome... I'm still somewhat of a newbie at this stuff myself... and I in NO WAY wanted to become long haired about it... and that's why I have stayed back a bit. But by process of osmosis I learned enough to get interested and got hold of the three basics:

1) Watts is the key
2) Gotta have a wattmeter
3) Motocalc will save you money and frustration


100 Watts per lb is good 150+ is really what I want for 3D... I'm trying to get 200 watts per lb on these small planes but can't quite get there seemingly... seems the 140-160 wtats per lb is the norm in this size plane.

I didn't catch that you wre suing e-propsw instead of slowflyer... yep as you saw big difference in these smaller planes... as you get larger, the plane's weight begins to flewx the blades an dyou must step up to an e-prop.

As emnm79 mentions, the Park 450 outrunner is a 12x6 motor, at least from the calcs and my personal experience with it. A good practice is to have a couple of each sie from say 10x3.8 to 12x6... hook up the wattmeter and check rpms.

Try the 12x6... you'll draw close to 17 amps and SHOULD drop to around 9.6 volts... 163.2 watts per lb. Very nice for that plane... If you are only drawing 13 amps now and dropping to 9.8 you are running 127.4 watts... Still decent but noticeably less power than the 12x6.

And some airframes require different props.... usually though bigger is better in these smaller planes... faster planes are more happy with smaller props, higher pitch and perhaps higher cells... foe example say a 9x6 on 4 cells (14.8 volt) may still draw 18 amps but have a pitch speed 20 mph more than the larger prop on less cells. A small pylon racer would benefit from this as the added weight is not an issue, speed is...


On yours prop it until it's right at or slightly above the motors max current at full throttle. Make sure that this figure is not too much for your ESC or batteries and you will be golden... this is assuming 3 cells which is pretty much the optimal votage for most of these smaller 3D airplanes.

As Trogdor mentions... now that you have discovered slowflyers props it likely that the batteries are your troubles... more amps may be causing the packs to drop considerably lower in voltage evening out the motors.

BTW... What is a HL 400XT? There may be a difference there too...

The HL 400xt is put out by Hobby Lobby it is under the Esskay brand. It is a good bargain, it flys an Eflite YAK-54 with plenty of power but going up 4oz and the big fat wing on my HL Extra 330 EP makes for a slow pull out from hover.

I agree with all of you guys and have just been putting off purchasing a watt meter for too long, I see now that it is a vital tool and I must get my hands on one. I should have one by the end of the week as the shipment just arived at my LHS and they will unpack this afternoon. Hopefully one was shipped.

Are you guys balancing your lipo's, if so how and what else should I purchase?

How often do you cycle?

Speaking of those 400XT motors... Hobby Lobby has them on sale for only $20!

The state: Mysteriously powerful motors

Reminds me a lot of those Altoids... "Curiously Strong"

They are good little motors but can only be mounted in front of a firewall, they fly the Eflite YAK-54 really well. For $20 you cant go wrong they are worth at least a science experiment.

I have to go bigger on the prop not enough watts, the 450 is making 119 watts and the little 400 is making 122. I am switching over to Deans plugs from JST, I might be bottlenecking a little bit. Got a new TP 1320 and am only pulling 10 amps. I never made it out to the LHS to pick up more props to play with, I have been working on my BME YAK as you know, its finally done and ready to fly.

Found an Eflite 12x6 in the garage from one of my YAK kits. The 450 on the 12x6 =130 watts on the new TP 1320. It will hover the plane no problem at a little less than half stick position, it was almost at 3/4 with the 10x4.7. It is also cold in my garage only about 50 deg F. I should get more power on a warm day right? Does any one have a loss calc for temp? Oh, well got the watt meter, got the bigger prop, should have went flying instead of watching the Super Bowl, it was a nice day.

That's interestnig results Big Barry... and about the temperature I really don't know... Iwas under the impression that cold packs didn't put out the voltage or amps or something... as 70-80 degree packs... and pehaps that's it. At 130 I'm sure it's doing just fine, but I would think you'd get up there around 150 so I suspect your still not getting best performance...a nd it may well be due to the temp... but 50 doesn't seem so low to me.

I suume you are around 14 amps at full throttle and droping to around 9.8 volts or so?

Isn't it cool to have that meter? It's like looking at all those 3D things that came with crackerjacks & cerail boxes that's just a jumble of red and blue lines.... then you put on the special glasses and VIOLA! it's all perfectly clear.

Same with the Wattmeter... it all seemed confusing til you hooked it up and you immediately knew you were underpropped. Be careful that thing will make e-investing even more attractive and even addictive now...

Now to get that MotoCalc8.. . Actually you can download it for free and try it for 30 days. Then you can paypal I think for registration number and turn it back on.

http://www.motocalc.com/

Imagine being able to test out different motors and prop BEFORE you buy and be reasonably sure of theperformance level... Simply too cool.

Ya its a fun toy and I am already making a list of props to try out. Do you use a Lipo balancer, if not are you going to get one?

I haven't at this point... because all my current packs are "old school" and don't have the taps.

All my future ones will have them though as the manufacturers have "seen the light" in that this is important for proper pack maintenance and safety.

Haven't even looked into it yet as fas as who offers what...

I currently have an ElectriFly Poly4 that I like well and hope to contiue to use... I also have a MiniRon Mobil that has 5 ports and the latest frimware seems to support the Lipos better. (Been testing it the last couple days).

Have you come across any balancers that maybe I should check out?

There is an article in this months Quiet Flyer on the Thunder Power unit. I am thinking about getting one in the near future as I add some more batts to the arsenal. I have to get some 2100mah for the Mini Edge.

The HL Extra 330 EP zips along now with the 12x6 SF prop on the 450. Like night and day, what a difference a prop can make. Everything was better and verticle is really good now, the plane zips right out of my hand. I had three guys watching me fly and they couldnt get over the power, I would hover it above their heads and then hit full throttle-climb and then go into a rolling circle, the plane is alot of fun to fly now and I am still getting ten minute flights. I can tell the difference between the new TP 1320 at 13C and the old ones rated at 10C. Plus the new one lasts a bit longer on the power.

I was going to give up on the 450, I am glad I got the watt meter and listened to you guys, the 450 has plenty of power for this 15oz plane I now have a better understanding of my brushless motors and their capabilities. Now I get to start proping the 480 and find out what it can do.

Yeah that's another variable. If you are drawing current near the max level of a pack the voltage drops more resulting in less watts (or similar) but at a higher current draw yeilding less performance (or similar) and lower flight times. Because of this you usually end up at higher throttle to get adequate performance... thus lower voltage/higher amp draw... etc.

A pack that is optimally drawn on doesn't drop voltage as much providing more watts at less amps. So you fly with a little less throttle. The combination of these two factors lead to longer flight times. Of course we often splurge inthe extra power and end up with the same flighttimes, but at better performance.

Did I word all that right?

Anywho... I think ThunderPower would have been my first place to search for a balancer as I usually choose their packs...

Big Barry,

here's my latest project... I converted my priginal scratch built trainer 63" to electric... then got a camera mount out I bought nearly 4 years ago...

It's all mounted up underslung on the CG... should work real nice with a digital camera...ght after taking these pics I added the servo screw and the last frame screw to tighten everything up.

I look forward to getting some good arials of my field...

That is totaly cool, it would be awsome to get some video also. How does the plane fly with that mount, I bet it slows down really quick.

I saw some cracks in the covering on my electric, turns out I cracked the fuselage in half in two places. I dont think this plane was intended to do blenders. It was funny because I flew at around 9:30 am and then again at lunch time and at lunch the trim was different and I noticed that knifedge was using more rudder, but overall the plane was still flying nice. Good thing I didnt do any blenders at lunch. I broke an Eflite YAK-54 in half doing blenders, it does a better blender than the HL Extra but its only good for about two really good violent ones. The blender when done properly exceeds the speed of foam. I will stop doing blenders with these little profiles they flex too much and dont have the inertia to really flat spin anyway, but it was looking really cool spinning it into an inverted spin, the palne does stop falling it just doesnt get into a good flat spin.

I haven't flown the plane with it yet, but I'm sure it'll add some drag.

My traoner was scratch built as I mentioned above, and is VERY light for a 63" wing... 3.5lbs all up glow or electric. I selected a motor that woul doffer good performance for a trainer... it has plenty of power for big consectuive loops and will roll forever.

Now ny adding about 9 oz, that'll change and become just a level flyer that putts around... but that's just what you want with a camera.

Neat idea about video... My digital camera has a video feature and a 256 meg ****m card so I will try some video too... though usually the video is never the best of quality in these things. One of the newer miniDV cameras would do the trick though.

I did a review a long while back of one of those wireless cameras, but the one I used was fairly short range and I kept getting interference from the prop on electric and too much vibration on glow...

Yeah them blenders can be hard on a plane but sure are awesome to watch... I bet the [link=http://www.airfoilz.com]Airfiolz[/link] design will take them though... it's got 3 layers of laminated foam with two full length balsa spars...