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proteus206
07-04-2009, 03:02 PM
I'm looking to get the Catalina soon, but don't need the radio system. Unfortunately, they seem to only list it complete or bare airframe.

I have lots of micro servos and LiPo's from my helis, but with this one I was wondering if anyone has some power systems, advice on what would work best with this plane and/or has fitted brushless to it. I would imagine my heli motors 3500Kv and up would be too aggressive for this one and it would likely be more efficient direct-drive anyway.

Just getting into electric planes, so a bit behind the curve when it comes to props and such for these. Seems to be quite a bit of difference with nitro.

winghobby
07-05-2009, 03:59 PM
hmmm your heading is abit confusing with the NITRO bit.

Any particular brand you are looking at for the Catalina? The one i'm familiar with is the Greatplanes one. Mine runs on two GPMG4560 28-30-950kv RimFire motors, which is equivalent to a 28mm dia size outrunner, 30mm in length and runs at 950kV (rpm)

alternatively, you can use the gpmg4590, which is a slightly bigger and more powerful motor, specs are 35-30-950.

http://www.winghobby.com/product_info.php?cPath=23&products_id=155&osCsid=a16ed5c17e2a56ae8398a9cd99939ec2

Grasshopper
07-05-2009, 04:32 PM
I think he may be talking about the PBY from Nitro Planes

http://www.nitroplanes.com/new204chkara.html

proteus206
07-05-2009, 05:20 PM
Yep, that's the one. Only, I was looking at the bare bones kit that comes with no electronics or power system.

http://www.nitroplanes.com/4chcararecoe.html

Jim Casey
07-08-2009, 03:48 AM
You can get the manual on their website.
The standard power system is pretty wimpy:


Wingspan: 1380mm (54.3")
Length: 880mm (34.6")
Flying Weight: 780g (27.5 oz)
Drive System: Twin 370 carbon brush motor with gearbox
Speed Controller: 25A speed controller
Servo: 3x10g
Battery: 8.4 V 1000mah Ni-MH
Control system: 4 CH Multifunctional Radio Transmitter and Micro Receiver
Radio Control Range: > 1000 feet (300m)

So with a couple of 400-size outrunners and a 3S 1200 LiPo pack you should be able to rip it off the water.

proteus206
07-08-2009, 03:53 PM
As a heli guy that's where I get into some confusion. What Kv are you recommending on the 400 size motors and would they use the existing gearbox or go direct drive?

Larry3215
07-09-2009, 05:16 AM
I would recomend you go direct drive with a small outrunner - BUT... a few details need to be worked out to determine which one to get.

What is the max prop diameter you can swing?

That will help determine the kV you need for the motors.

What size pack are you wanting to use? Cell count and mahr? Id guess a 3S1P in the 2100-3000 mahr range would work fine depending on the answers below.

What size speed controllers you will want to use will depend on the quality of the controllers and the total power you want.

How are the existing motors mounted? Do you need to use the same mounting system or can you change it to suit the motor?

Answer those questions and we can help pin things down better for you.

They claim a flying weight of 27 ounces. Those numbers are usually optimistic so Id plan on a 2 pound all up weight or a little over.

If it was my plane Id want at least 100 watts per pound to maybe 150 watts per pound for good ROW so you need each motor to produce about that amount of power.

So on a 3S lipo each motor will be pulling between 10 and 15 amps to hit those power numbers.

proteus206
07-09-2009, 03:07 PM
Thanks Larry. Quite a coincidence looking at your avatar, but I remember the 100W/lb rule from some earlier research into the possibility of flipping the Northstar over to electric, (with 3 spare nitro motors that idea was shelved early). I'm building 2 at the moment, one for a friend and I and I just encountered your thread about the second foamie in the pic last weekend and D/L the plans. Seems easy to build, but I could not find anything regarding where you fit the electronics and waterproofing. This may end up added to next winters build list if the wife doesn't get too uppity about foam dust:blah:.

Regarding the Northstar, have some questions about your cover scheme and CofG, but that can go over to a PM if you'd like. Within a week or two of handing over the one and finally getting to covering mine and already have the Ultracoat colors to try the Coast Guard pattern.

Getting back on subject: Like you surmise, intend to run no larger than one of my heli 2200MAh/20C packs and seem to remember reading that the stock props are in the 9/6 or 9/8 range. Normally, on the helis I like to give myself some room with ESC ratings and buffer using the 1.5X rule. That would come close the the ESKY 25A I have available, although I have switched most of the small helis over to Pentium and like their reliability. I was wondering in this case if it would be advisable to bring the ESC's out to the nacelles for better cooling and reduced R/F. In my case I would also be looking into mounting a whip antenna down in the fuse.

In the end this plane will see the minimal aerobatics recommended by the manufacturer, (that will be left to my new foamie Extra 330) but our new approx 200X400' pond was carved out of the earth and has all that dirt piled around it to form a 3-sided bowl with sides gradually rising up to 10-15' high. The plane will have to climb out of that. On side #4 where we have the access road there are trees opposite the pond I would have to contend with. This was our original spot for the Northstars before the recent nitro ban there, (the reason I'm looking at the Cat now) and likely the tightest area I would have to deal with. The Cat likely would stay within the confines of the pond area as water work would be the primary objective.

In the winter there is a large and flat empty field on the other side of the berms and I would be trying this off snow.

Hope that covers all the bases.::o

winghobby
07-09-2009, 03:37 PM
sea planes in general have a pretty high drag when taking off from the water surface, thus you may want to get one with a smaller kv, which will give you a much needed torque instead!

Larry3215
07-10-2009, 02:51 AM
Thanks Larry. Quite a coincidence looking at your avatar, but I remember the 100W/lb rule from some earlier research into the possibility of flipping the Northstar over to electric, (with 3 spare nitro motors that idea was shelved early). I'm building 2 at the moment, one for a friend and I and I just encountered your thread about the second foamie in the pic last weekend and D/L the plans. Seems easy to build, but I could not find anything regarding where you fit the electronics and waterproofing. This may end up added to next winters build list if the wife doesn't get too uppity about foam dust:blah:.

Regarding the Northstar, have some questions about your cover scheme and CofG, but that can go over to a PM if you'd like. Within a week or two of handing over the one and finally getting to covering mine and already have the Ultracoat colors to try the Coast Guard pattern.

Getting back on subject: Like you surmise, intend to run no larger than one of my heli 2200MAh/20C packs and seem to remember reading that the stock props are in the 9/6 or 9/8 range. Normally, on the helis I like to give myself some room with ESC ratings and buffer using the 1.5X rule. That would come close the the ESKY 25A I have available, although I have switched most of the small helis over to Pentium and like their reliability. I was wondering in this case if it would be advisable to bring the ESC's out to the nacelles for better cooling and reduced R/F. In my case I would also be looking into mounting a whip antenna down in the fuse.

In the end this plane will see the minimal aerobatics recommended by the manufacturer, (that will be left to my new foamie Extra 330) but our new approx 200X400' pond was carved out of the earth and has all that dirt piled around it to form a 3-sided bowl with sides gradually rising up to 10-15' high. The plane will have to climb out of that. On side #4 where we have the access road there are trees opposite the pond I would have to contend with. This was our original spot for the Northstars before the recent nitro ban there, (the reason I'm looking at the Cat now) and likely the tightest area I would have to deal with. The Cat likely would stay within the confines of the pond area as water work would be the primary objective.

In the winter there is a large and flat empty field on the other side of the berms and I would be trying this off snow.

Hope that covers all the bases.::o

Ive got family in town so I'll have to answer this in detail later.

Quick additional questions - do you have the model in hand? If so, how do the motors mount now - to a stick or fire wall? Can you measure the actual maximum prop clearance? Thats a critical piece of the puzzle so I dont want to guess on that part.

sea planes in general have a pretty high drag when taking off from the water surface, thus you may want to get one with a smaller kv, which will give you a much needed torque instead!

Thats why I was asking about the prop clearance. Its limited on this model, so kV will have to be chosen on the basis of the pack voltage and prop clearance and desired power output.

A lower kV motor will give more torque true, but you would need to spin a larger prop to make up the power or go with a higher cell count on the pack. Its easier to select a Kv to suit the prop clearance and pack voltage at the desired power output.

Becides, what he needs is thrust rather than torque and thrust is mostly a function of prop diameter and to a lesser degree a function of rpm. The diameter is limited, so we will need to go for extra RPM to make up for that.

proteus206
07-10-2009, 03:50 PM
No, I don't have the plane in hand. Was hoping someone else could jump in with info.

As stated, NitroPlanes sells these complete or minus radio and power systems. With no need for their version of a radio system, I'm a little miffed to think the only way to go that option is to get it stripped of everything! would have been nice if they had some listing for a brushless upgrade. Oh, well, figured this would make a good excuse to search for a more efficient drive set.

I just can't justify sticking a pair of $45+ motors and their $30 ESC's into a $50 aircraft.

This reminds me of when my mother went to look for her last new car. With a new hip she needed power seats, but the only way the were offered was in a "Package" that included a moonroof, roofrack and a trailer hitch. Now, what would a 76 year old need with a roofrack she couldn't reach or a hitch?!!!!!!!!!!!! To top it off, the fabric seats felt like a park bench, so to add comfort would require leather seats, now with heating, (anyone living in Canada can relate to hopping onto a cold seat in the middle of winter:censor:) and they were only offered in a "Package" again that now included side air bags. See where this is going?

Sorry to spew, I just don't like restricting my options, which is why I tinker so much.

winghobby
07-10-2009, 04:33 PM
then get a $200 aircraft to justify the $45 motors and $50 ESC =D

on a more serious note, if you're thinking of getting something good, then do not compromise on anything else...its kinda an all or nothing situation...either you go really cheap, or you go all the way....no point putting a hacker on a cheap china model only to find your firewall mount flying out midway tru flight, or viceversa, putting a cheap and inferior quality esc and motor on a gp model.

in my opinion brushed motors are good enough considering the price of that model...so stick to it, they can be rather powerfull too ;)

Larry3215
07-10-2009, 06:54 PM
Thanks Larry. Quite a coincidence looking at your avatar, but I remember the 100W/lb rule from some earlier research into the possibility of flipping the Northstar over to electric, (with 3 spare nitro motors that idea was shelved early). I'm building 2 at the moment, one for a friend and I and I just encountered your thread about the second foamie in the pic last weekend and D/L the plans. Seems easy to build, but I could not find anything regarding where you fit the electronics and waterproofing. This may end up added to next winters build list if the wife doesn't get too uppity about foam dust:blah:.

If you mean the Capricorn, the electronics - rx and esc - go in the space under the center 'V'. Servos are on top. There is detailed info on CorrosionX water proofing in post 3 or 4 in that thread. CorrosionX is the best way - by far - to protect your goodies if you fly off water.

http://www.wattflyer.com/forums/showthread.php?t=26120

If you talking about the XXL Polaris or the original I based mine on, the electronics locations are called out in Steves plans somewhere. Check the first post in my thread and there is a link to Steves build thread on RCGroups. All the details are in there somewhere.

http://www.wattflyer.com/forums/showthread.php?t=41896

The locations are not at all critical on the Capricorns and I doubt they are on the Polaris either.


Regarding the Northstar, have some questions about your cover scheme and CofG, but that can go over to a PM if you'd like. Within a week or two of handing over the one and finally getting to covering mine and already have the Ultracoat colors to try the Coast Guard pattern.

Here is fine or a PM. Im easy :)



Getting back on subject: Like you surmise, intend to run no larger than one of my heli 2200MAh/20C packs and seem to remember reading that the stock props are in the 9/6 or 9/8 range. Normally, on the helis I like to give myself some room with ESC ratings and buffer using the 1.5X rule. That would come close the the ESKY 25A I have available, although I have switched most of the small helis over to Pentium and like their reliability. I was wondering in this case if it would be advisable to bring the ESC's out to the nacelles for better cooling and reduced R/F. In my case I would also be looking into mounting a whip antenna down in the fuse.

You want to keep the battery side leads as short as possible, so its best to extend the motor leads if anything needs to be longer. If the esc's need to be kept cool, mount them just outside the fuse under the wing - after treating with CorrosionX.

Its hard to tell if that fuse has an air inlet and outlet to keep the pack cool. Many of the arf's these days dont allow for that and its a major mistake. Lots of guys are afraid of getting water inside but you must keep the goddies cool or your dead anyway :)

In the end this plane will see the minimal aerobatics recommended by the manufacturer, (that will be left to my new foamie Extra 330) but our new approx 200X400' pond was carved out of the earth and has all that dirt piled around it to form a 3-sided bowl with sides gradually rising up to 10-15' high. The plane will have to climb out of that. On side #4 where we have the access road there are trees opposite the pond I would have to contend with. This was our original spot for the Northstars before the recent nitro ban there, (the reason I'm looking at the Cat now) and likely the tightest area I would have to deal with. The Cat likely would stay within the confines of the pond area as water work would be the primary objective.

In the winter there is a large and flat empty field on the other side of the berms and I would be trying this off snow.

Hope that covers all the bases.::o

In that case you need to balance power with excess weight. Id recomend at least some half decent motors and controllers so you have a modicum of efficiency or you may end up with a flying pig that wont slow down and cant climb out decently.

No, I don't have the plane in hand. Was hoping someone else could jump in with info.

As stated, NitroPlanes sells these complete or minus radio and power systems. With no need for their version of a radio system, I'm a little miffed to think the only way to go that option is to get it stripped of everything! would have been nice if they had some listing for a brushless upgrade. Oh, well, figured this would make a good excuse to search for a more efficient drive set.

I just can't justify sticking a pair of $45+ motors and their $30 ESC's into a $50 aircraft.

This reminds me of when my mother went to look for her last new car. .......

Sorry to spew, I just don't like restricting my options, which is why I tinker so much.

I understand how you feel about that. However, you just killed all the motors I was going to recommend. The esc's Id go with are more than $30 each too :D

Next best bet would be some Scorpion motors and controllers of the correct specs. You will have to get some other advice on which one as I have never used any myself. They are probably still going be over your budget though.

If you really need to stay under those numbers you're probably stuck with some of the HobbyCity/King "stuff" and I am no help there at all. You CAN get the same "stuff" from reputable US dealers for almost the exact same price so Id recomend you at least do that. You will get some customer service that way and keep some of the money in the US. Your power system will also be heavier and less efficient.

Those are the trade off along with reduced reliability and reduced flight times.

Since you dont have the plane in hand, you cant really make a final decision on power system yet.

Prop size is absolutely critical to know ahead of time. You cannot choose a motor untill you know that with certainty.

You also need to know how the motors will mount. Some outrunners can easily be stick mounted and some cant and some can easily be reverse mounted and some cant. So you need to know how its going to have to mount and/or if you can easily change the mounting in the nacells if need be.

A buddy of mine has one of these and it flys reasonably well for a small model. He went from the brushed motors (it would barely take off) to a set of cheep outrunners and esc's to get more power. He is now in the process of replacing the cheep motors/esc's he chose for ones that are more reliable. He's finally fed up with power systems issues and having to retrieve the plane from the middle of the lake :D

proteus206
07-10-2009, 09:26 PM
Thanks for the info. Radio location was for your Capricorn. I'm familiar with CoroX from my days in aviation. Now have access to LPS3 a lot more.


Still just as conflicted on which way to go, though. Might have to stick with the brushed and stuff a LiPo into it if I want to get this going before the end of the season here. Upgrading can wait till winter winds keep me stuck indoors. Will also give me a chance to meet up with some local indoor flyers and see what they use. Who knows, the club Swap Meet is due near Christmas, (or I can talk myself into a present for myself:silly:).

Another simple question, but generated from my recent experiences into what NOT to use on foam, is your recommendation on the best glue for foamies. Does the blue foam require something different than what these ARF's are made out of?

From my perspective, looking on a map you don't seem too far away from one of my heli buddies that lives on Camano Island.

Larry3215
07-11-2009, 04:49 PM
Thanks for the info. Radio location was for your Capricorn. I'm familiar with CoroX from my days in aviation. Now have access to LPS3 a lot more.


Still just as conflicted on which way to go, though. Might have to stick with the brushed and stuff a LiPo into it if I want to get this going before the end of the season here. Upgrading can wait till winter winds keep me stuck indoors. Will also give me a chance to meet up with some local indoor flyers and see what they use. Who knows, the club Swap Meet is due near Christmas, (or I can talk myself into a present for myself:silly:).

Another simple question, but generated from my recent experiences into what NOT to use on foam, is your recommendation on the best glue for foamies. Does the blue foam require something different than what these ARF's are made out of?

From my perspective, looking on a map you don't seem too far away from one of my heli buddies that lives on Camano Island.

LPS3 looks interesting. My concern is the flash point is listed as 100 deg F and speed controllers can run at twice that temp easily.

Remember my buddies experiences - with the stock brushed setup the plane barely flew. You could put a more powerfull brushed setup in it, but it will be significantly heavier than even a cheepo brushless setup of equal power. Brushed setups in the typical gear boxes they come with are typically in the 50% efficiency range and possibly less. Even the worst brushless setups will be in the hi 60% to low 70% range.

So if it takes 200 watts input to fly it brushless, thats say 140 watts out to the props. To get the same performance with brushed motors in plastic gearboxes, you will need about 300 watts input. So with the same packs, you will have 50% less flight time plus the added weight you will be carrying.

A 20% hit on efficiency represents a HUGE hit to performance. Even 10% is significant.

Thats not to say it cant be done but its going to be a very different animal.

Kind of like a Volkswagen van full of drunk sumo wrestlers vrs a Shelby Mustang with one hot babe in the front seat :D

The blue and pink building insulation foams are variations on Styrofoam. So any glue that works on Depron or fanfold will work fine with them. Foam safe CA, Epoxy, Gorilla or any of the polyurethane expanding glues, Elmers white or carpenters, Tightbond, hot glue, etc. I use them all depending on the application. I mostly use the Gorilla types on the big models and Foam safe CA on the small ones with a healthy dose of epoxy here and there. It just depends.