Brushless Upgrade and Motor Mounts

[iflyforfun]

ginginho

Stock SC LP =. 25.2 oz. ( published weight ) When I bought my SC the first thing I did was assemble it and check the weight and balance. It was over the published weight and topped the scale at 25.6oz.

Over time I have done some mods as mentioned above.

My current current flying weight is exactly 28.5 oz or 810.2 grams
This current flying weight includes the following mods.
1. 2.5 " wheels
2. Aileron mod
3. Battery Box Mod. ( only cut out web to allow vertical install of lipo)(added some
foam)
4. Turnigy 2200mah Lipo Battery
5. Cut angle hole underneath and behind cowl to allow insertion of mini DV camera.
(same camera that Dillzio had or has on his Cub)

That is my current configuration and exact flying weight.
I also have the plane's COG at 2.3875" from the LE(leading edge)

I stated above that I have flown with a total weight of 37.5oz

This was before my aileron mod, with the stock wheels, and with my Sony HD-cx-150 video Camera mounted to the plane.( not the current configuration.)
This was also with the stock battery and a balsa tapered platform that I used to make the top of the wing the correct angle.
I rounded that number off from memory but looked it up this morning and the actual flying weight was 37.98oz
Landing speed was very high. I said it flew like a brick but I should have said that it climbed like a brick(slow and with WOT). Once airborne and level it flew great at WOT. It tended to be a bit lazy coming out of a turn and I did not want to push the envelope being so underpowered. I will post the video and pictures of the flight on YouTube as soon as I get a chance.

There are many factors that relate to each other when talking about aerodynamics. Wing loading and flight characteristics have many variables and way to much to try and talk about here.
Generally speaking,

High wing loading
1. Longer takeoff roll
2. Slower climb
3. Higher stall speed
4. Faster and steeper glide
5. Faster landing speed
6. Harder to control if you don't have enough power.

Add a overpowered motor to a high wing load and most of thease factors change.
1. More power= faster acceleration= shorter takeoff roll
2. More power= faster speed=faster and steeper climb
3. Stall speed does not change
4. Glide stays the same
5. Landing speed stays the same
6. Flying characteristics can be excellent if the plane is balanced correctly.

To find the COG you must find the thickest part of the wing back from the leading edge.
I have found this to be 2.250 or 2 1/4" inches from the leading edge. Ah, I think I see where some confusion may be. I made a typing error on the last few post and put down 1.250 and 1.3875"
O my god. That should be 2.250 and 2.3875
I don't even want to think about what would happen with a COG of 1.anything

20 years ago I built and flew a scale Cessna 172. I wanted to experiment with it and calculated the scale wing loading to be exactly scale in relationship to a real Cessna 172.
I remember having to add so much lead weight to the body that I thought that the plane would never get off the ground. But my calculation said it had to fly. I put a .60 nitro motor in it and it flew great. It was blazin fast on approach but flew fantastic.

I like to tinker with toys. I like to push the envelope. If you are adventurous and want to confirm what I am saying. Do the following.( only if you have the piloting skills )

Take a STOCK Super Cub LP with stock battery.
Keep adding 1 oz weights to the top of the wing and always checking your COG before you fly.
Then take her up.
You will be amazed at how she flys when your up in the 35 oz range.
Your flight characteristics will be much more scale and real like.
Only power will be lacking for a nice climb out.

And remember you will need more power and speed for landing.

[iflyforfun]

Stock RX/ESC combo weighs 39.42 grams

[Dillzio]

Aug 26, 2010 13:40:48 GMT 1 leisureshoot said:

Aug 26, 2010 11:03:17 GMT 1 Dillzio said:

I got one of these scales off of ebay:

cgi.ebay.com.au/22LBs-10Kg-5g-Digital-Luggage-Fishing-Portable-Scale-10-/170457096468?pt=LH_DefaultDomain_0

Perfect for the price. You can use it as a thrustmeter too :-)

Nice looking motor mount, . I think it's much better to have a nose heavy plane, since it's much easier to correct. I can't even put profilm on my tail, because it would throw out the centre of gravity too much.

Nice find. Thanks.

I wish I were nose heavy at this point. The wood is much lighter than the motor it replaced. I've attached several metal nuts to the side and bottom of the mount for now. I've got it just about right.

You'll find you can correct the CG with less weight by mounting the weights as far forward as possible. This means mounting them to the cowl.

I've wrapped my cowl with cloth tape to make it stronger (and heavier). An easy way to adjust the CG is to simply use the cloth tape to stick a lead fishing weight to the top front of the cowl.

[leisureshoot]

Aug 27, 2010 9:53:50 GMT 1 Dillzio said:

Aug 26, 2010 13:40:48 GMT 1 leisureshoot said:

Nice find. Thanks.

I wish I were nose heavy at this point. The wood is much lighter than the motor it replaced. I've attached several metal nuts to the side and bottom of the mount for now. I've got it just about right.

You'll find you can correct the CG with less weight by mounting the weights as far forward as possible. This means mounting them to the cowl.

I've wrapped my cowl with cloth tape to make it stronger (and heavier). An easy way to adjust the CG is to simply use the cloth tape to stick a lead fishing weight to the top front of the cowl.

Yeah, I can't seem to keep cowls more than a month.
I was considering having a prop turned from gold alloy. Do you think that would help?

[iflyforfun]

I will take the advise of you more experienced electric flyers and go with the Turnigy 35-30C motor.
flydiver,thanks for sending me the link " a very smart man".
My upgrade will look like this.

1. Turnigy 35-30C Motor
2. Custom RC Parts Motor Mount - cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=250591252393&ssPageName=STRK
3. Turnigy Plush 30A ESC - hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=2164&Product_Name=TURNIGY_Plush_30amp_Speed_Controller

I have already done a aileron mod and also added flaps.
The rudder and elevator are using the 2 stock SC servos.
I am using 2 HXT900 servos for the ailerons and 2 HXT900 servos for the flaps.
This brings the total to 6 servos and there lies my concern. Could someone recommend a BEC for my setup.
I also noticed that the 30a esc was out of stock and was not sure of a good replacement. Any recommendations would be great!!!

I have read many times that you need to program the ESC. Could someone please explain( or send a link) of what needs to be programmed,why and a recommendation for a programming tool. I have not been able to locate a good thread or in depth discussion on ESC programming.

I have a request and hope that someone would be so kind as to indulge me with the following.
I think I am starting to understand how all the individual components of electric RC work but am still having a little trouble tying it all together in a complete package.
For example, your transmitter transmits a signal to your receiver and your receiver processes this signal and tells your servo to move to a certain position.
The BEC ( some have a letter U or S before the BEC, why? ) maintains a constant voltage( power source ) for the receiver and must be rated to supply this constant uninterrupted power depending on how many servos you want to power. And that's about where I will stop with my trying to understand the rest. What about the ESC? What is the receiver telling the ESC to do and how is the ESC working in relationship to the battery and motor and so on and so on. I would love a explanation that could be understood by a 10 year old. I have read so many articles and so many threads in the past few months but it seems like I'm just missing that little bit that will bring it all together.

I finished doing the flap mod on Saturday and would really like to install my new AR6110e
RX and do a little flying while I waiting the next few weeks to get all my parts from HK. In order to do this I will need to get a Brushed ESC and a BEC as quick as possible to use with the stock motor. Can someone recommend a Brushed ESC and a BEC that is available here in the US that is cheep and I can get within a few days. This just needs to get me thru the next 4 to 8 weeks while I'm waiting for the new parts to arrive and to finish the mod.

I went flying yesterday and tried out my new floats. Maiden flight. O boy, big mistake.. I got that old disease "flyitis" and was not willing to wait another hour till the wind died down. The first flight was a disaster and needless to say I had to wait about 20 minutes for the plane to be blown back to shore upside down. :-(
After letting it dry for a few minutes " flyitis" kicked in again and I tried again with better results. It was still blowing really bad but I managed to keep her upright.

Here is a short video of my crash.

[flydiver]

You have any idea what you are asking for? That's a mess of info.

From the bottom-if you ditch your plane in the water consider it drowned. DO NOT try to fly it. Remove the battery ASAP. Do not attempt to power it up until it's completely dry which often takes 2-3 days. You may have to remove shrink from the ESC and maybe the RX to do this well. Otherwise you risk frying everything.
You got away with it-pure luck.

BEC-battery eliminator circuit. UBEC is a brand name. S-BEC means it is switching, most of them are switching which is better than linear. Linear makes heat to reduce the voltage.

What we think of as an ESC is really an ESC + BEC > 2 separate devices. The ESC controls the motor RPM and motor voltage.
The BEC powers everything else and provides LVC.
When you get a separate (U) BEC and pull the red wire on the ESC you essentially disable the ESC BEC leaving only the ESC.

Turnigy plush = hobbywing = volcano = a number of others.
www.hobbypartz.com/bescesc.html
Get the programming card. If you see that programming card is available for a particular ESC, it's a hobbywing.

The 30A has a 2A linear BEC, the 40A has a 3A switching BEC. If you use a UBEC (and you should with 6 servos) it doesn't matter as long as you have suitable ESC amp headroom for the motor.

ESC Programming is almost as much art as science since the algorithm that runs it is specific to THAT product and is likely NOT the same as another ESC.
homepage.mac.com/kmyersefo/timing/timing.htm
This is only part of the story. It took me 6 MONTHS of reading to get a handle on it and I'm still learning. Most folks have a limited understanding of an ESC.

Mostly, if it works, don't bother programming until you know more.

A few motors need programming to work right. A VERY few may need SPECIFIC programming to work at all and/or not fry. There are a few Turnigys like this but there are generally lots of warnings. Occasionally you'll find a motor that runs fine on one ESC but won't on another. Don't fight it > switch.
Castle is one ESC that has firmware upgrades. Different firmware can run a motor quite differently.

[iflyforfun]

Hi Flydiver, you are correct!!! You should never power up your equipment unless you are sure that you have taking all the steps necessary to insure it is dry.



As you see by the picture I have a complete stock new motor for my plane.

After it blew to shore I first disconnected the battery, removed the wing and inspected the RX and I was shocked that it did not get wet. I was expecting that it would have been soaked. The foam that I glued into the battery box when I did the battery box mod prevented any water from reaching the RX. I then took all of about 10 minutes and changed the motor and gearbox, installed a fresh battery and was off for my second attempt.

Yes, I am aware of the amount of information that I'm asking for. This is a thread that many can read and if willing many can answer. I never expected any one person to try and answer all my questions.

You have provided me with a bunch of great information!

Thanks :-)

[flydiver]

You know about BRUSHED water break-in?
www.wattflyer.com/forums/showthread.php?t=5788&page=2

I used this once to fix a used stock motor that was cutting out on me. I did all the other 'glitch' checks without success. I figured it wouldn't hurt and was surprised when it removed the problem, though I doubt it would work for everyone with an erratic motor.

[Dillzio]

You're getting the same motor, and motor mount as me, and a nearly identical ESC. Nice choice! Admittedly though I still haven't maidened my cub yet, I've been short on time with my new uni course and it always seems to be windy here in winter.

So, you have the camera setup from my old cub and the motor setup from my new one. Best of both worlds If you got the motor and mount combo idea off me too then I do believe you own me a drink! It's OK, I can wait for it. You planning on coming down under any time soon?

Say, did you hear/read about what happened to my first cub? It's a tragic tale indeed, but you'll get a good laugh out of it at my expense - everyone else here seems to have anyway.

If you want to make life easy for yourself get an ESC programming card, it makes things MUCH easier. The only thing you can't do with the card is program the throttle range, but you do that like so:
1) turn on Tx
2) set throttle to full
3) Connect battery to ESC/motor
4) Wait for it to beep at you (but don't wait too long, or you'll go into manual programming mode, which you won't need if you have the card)
5) set throttle to zero
6) wait for it to beep at you again
7) DONE!

If you want to expand your expertise, here are some of my favorite references:
all about electronics, plus more
www.stefanv.com/#rcstuff

trimming control surfaces and how they work
www.modelaircraft.org/MAG/FTGU/Part%2031/31main.html

everything you ever wanted to know (and more) about the HZ super cub
www.rcgroups.com/forums/showthread.php?t=852122


If you're looking for a decent BEC, try this one: www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=3735&Product_Name=HXT_UBEC_5/6v_output,_5.5~23v_Input

I got this one and found it to be crap: www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=10312&Product_Name=Turnigy_5A_%288-26v%29_SBEC_for_Lipo_

[ginginho]

Aug 31, 2010 3:50:11 GMT 1 flydiver said:

{snipped}

BEC-battery eliminator circuit. UBEC is a brand name.
{snipped}

The U can also stand for Universal.

[iflyforfun]

flydiver, yes I have heard of the water "break In". I have not giving it any thought but will run it by one of our engineers.

Just a few pic's of the motors I work on.

Re-built Comutator

Coil Winding Area

Turn and Undercutting a Comutator

A re-built com ready to be installed on a shaft

Motor drying Oven

Re-stacking a motor lamanation stack


Motors can be washed and dried in an oven if you take the correct precautions. I can not imagine any benefit to a "water break in" other than to seat the brushes. But like I said I will ask one of our engineers and see what he says about it.

I placed my wet motor in my oven at home and baked it for 3 hours at 90 degrees. I do not recommend a higher temp because of the resistors on the motor. The normal procedure is to wash a motor then bake it at 375 degrees for 3 hours. This can only be done if no electronics or plastic is attached to the motor.
The down side of air drying a wet motor is rust forming in and on the bearings. For the price of what these motors cost I would recommend always having a spare motor laying around.

Dillzio, Hey, I will take you up on that offer for a pint. :-)
is it true that you drink your beer warm down under?

[ginginho]

Aug 26, 2010 15:45:25 GMT 1 iflyforfun said:

ginginho

Stock SC LP =. 25.2 oz. ( published weight ) When I bought my SC the first thing I did was assemble it and check the weight and balance. It was over the published weight and topped the scale at 25.6oz.

Over time I have done some mods as mentioned above.

My current current flying weight is exactly 28.5 oz or 810.2 grams
This current flying weight includes the following mods.
1. 2.5 " wheels
2. Aileron mod
3. Battery Box Mod. ( only cut out web to allow vertical install of lipo)(added some
foam)
4. Turnigy 2200mah Lipo Battery
5. Cut angle hole underneath and behind cowl to allow insertion of mini DV camera.
(same camera that Dillzio had or has on his Cub)

That is my current configuration and exact flying weight.
I also have the plane's COG at 2.3875" from the LE(leading edge)

I stated above that I have flown with a total weight of 37.5oz

This was before my aileron mod, with the stock wheels, and with my Sony HD-cx-150 video Camera mounted to the plane.( not the current configuration.)
This was also with the stock battery and a balsa tapered platform that I used to make the top of the wing the correct angle.
I rounded that number off from memory but looked it up this morning and the actual flying weight was 37.98oz
Landing speed was very high. I said it flew like a brick but I should have said that it climbed like a brick(slow and with WOT). Once airborne and level it flew great at WOT. It tended to be a bit lazy coming out of a turn and I did not want to push the envelope being so underpowered. I will post the video and pictures of the flight on YouTube as soon as I get a chance.

I assume this was with the stock motor too.

Aug 26, 2010 15:45:25 GMT 1 iflyforfun said:

There are many factors that relate to each other when talking about aerodynamics. Wing loading and flight characteristics have many variables and way to much to try and talk about here.
Generally speaking,

High wing loading
1. Longer takeoff roll
2. Slower climb
3. Higher stall speed
4. Faster and steeper glide
5. Faster landing speed
6. Harder to control if you don't have enough power.

Add a overpowered motor to a high wing load and most of thease factors change.
1. More power= faster acceleration= shorter takeoff roll
2. More power= faster speed=faster and steeper climb
3. Stall speed does not change
4. Glide stays the same
5. Landing speed stays the same
6. Flying characteristics can be excellent if the plane is balanced correctly.

I don't disagree with these points, however with the motor you are selecting you are very likely to make it heavier and hence increase wing loading and probably make it more nose heavy.

Aug 26, 2010 15:45:25 GMT 1 iflyforfun said:

To find the COG you must find the thickest part of the wing back from the leading edge.

I'm pretty sure that is actually the CoL, not CoG. The CoG should be forward of this by a small amount.

Aug 26, 2010 15:45:25 GMT 1 iflyforfun said:

I have found this to be 2.250 or 2 1/4" inches from the leading edge. Ah, I think I see where some confusion may be. I made a typing error on the last few post and put down 1.250 and 1.3875"
O my god. That should be 2.250 and 2.3875
I don't even want to think about what would happen with a COG of 1.anything

Aah, that CoG sounds a little more like it.

Aug 26, 2010 15:45:25 GMT 1 iflyforfun said:

20 years ago I built and flew a scale Cessna 172. I wanted to experiment with it and calculated the scale wing loading to be exactly scale in relationship to a real Cessna 172.
I remember having to add so much lead weight to the body that I thought that the plane would never get off the ground. But my calculation said it had to fly. I put a .60 nitro motor in it and it flew great. It was blazin fast on approach but flew fantastic.

I like to tinker with toys. I like to push the envelope. If you are adventurous and want to confirm what I am saying. Do the following.( only if you have the piloting skills )

Take a STOCK Super Cub LP with stock battery.
Keep adding 1 oz weights to the top of the wing and always checking your COG before you fly.
Then take her up.
You will be amazed at how she flys when your up in the 35 oz range.
Your flight characteristics will be much more scale and real like.
Only power will be lacking for a nice climb out.

And remember you will need more power and speed for landing.

Sorry, I don't have a stock SC LP. I've flown a few of my models many a time overweight, I know how they change when heavier. I've also flown some things with strange CoG's.

[iflyforfun]

ginginho, I deceided to go with the smaller 35-30 motor. After reading a few threads I have noticed that people have to add weight to the nose after doing a brushless upgrade.
I have not figured out how to insert someone elses quote. Feel like pointing me in the right direction?

I placed my order from HK last night and ordered both the 35-30C and the 35-36C. I also ordered a wattmeter and a bunch of different props.
As soon as all the stuff arrives I will swap out the equipment do some Ben h tests.
My order details are:
1x #TR35-30C-1100/3883 TR 35-30C 1100kv Brushless Outrunner (Eq AXi 2808) variations = $18.20.
1x #TR35-36C-1100/3886 TR 35-36C 1100kv Brushless Outrunner (Eq: AXi 2814 variations = $23.94
1x #SBEC-40V/10313 Turnigy 5A (8-40v) SBEC for Lipo  variations = $5.98
1x #XYH3B9x7-5/9015 3 Blade EP Propeller 9x7.5 / 229x191mm variations = $2.41
1x #XYH3B10x7/9016 3 Blade EP Propeller 10x7 / 254x178mm variations = $2.61
1x #APC9x6-E/5439 APC style propeller 9x6-E variations = $1.00
1x #APC10x5-E/5440 APC style propeller 10x5-E variations = $0.74
1x #TGPC-10x8/11346 Turnigy Type C Light Wood propeller 10x8 variations = $2.00
1x #0190060/6782 Stick mount 10mm stick / 3g weight variations = $1.25
1x #HK-010/10786 HobbyKing HK-010 Wattmeter & Voltage Analyzer  variations = $19.99
1x #OR23-602x10/9219 Ball and roller link 4.8x3x17mm (10pcs/bag) variations = $4.39

Now I have to wait. :-(
1x #EC3x10/9625 EC3 plugs (10pairs/set) variations = $5.99
2x #HXT500/663 HXT500 5g / .8kg / .10sec Micro Servo variations = $6.98
1x #BOX-183g/8040 Extra Size Cardboard Box and Packing 183g variations = $0.00

[iflyforfun]

Dillzio
Did you say you have added weight to your cowl in order to balance your Cub?
I think if I'm reading the thread correctly that Ginginho is concerned that the 35-30C or the 35-36C will make the Cub to nose heavy. What a re your thoughts on this?

[ginginho]

Ifly,
I think you'll find that the 35-30 will put a smile on your face, it'll certainly have a lot more go than the stock motor. You should also be able to mount your ESC in the cowl which will help with the balancing without the need to add extra (and unused) weight. A couple of comments about the props you've selected:
3 bladers - not very efficient when compared to 2 blades. Nice for pictures though.
APCe's - Nice strong props, however they are quite brittle, so grease those landings when these are fitted.
Wooden prop - Not used them personally, I have heard that they are relatively heavy compared to plastic ones. It may be useful if you have a rearward weight problem.

With each and every prop, check the current draw when they are fitted before flying, you may be surprised with the differences you see and you'll gravitate to one that hits the sweet spot for your setup.
Are you thinking of using the stick mount? I'd still be wary of this even though you've de-spec'ed your motor a bit.

I didn't see an ESC listed in there, do you already have one? If not and you need to add to your order (if HK will do this), it may be worth also getting a couple of GWS type props (9x6, 9.75x9.75 and/or 10x6). They work very well on the SC with a 200-250W motor.

As for adding weight to the nose, I didn't need to. My motor weighs 76g, home made mount with the ESC in the cowl gives the CoG as stated previously. See how it pans out once you've got it all in the bird. I doubt you'll need to if you use the Ebay mount and your 2200 pack mounted vertically as per the standard BB mod.