Hi everyone,
I currently have three GWS planes, bn2 islander, stick and A10. I just finished building the A10 and havnt flown it but i have had a little trouble with construction and i want to clear this up before i buy a formosa most likely and install my himax 2025 4200.
Firslty, with the A10 and the bn2 i found the ailerons very difficult to install. I cut very neatly and installed the plastic hines neatly but there was a definite lack in stability and movement. I found the foam was twisting from one end to the other so i may have had full aileron down at the control end but the other end was only down 1/4. They were quite stiff also. I used the stock glue as i heard it handled the hinges quite ok. Seriously though, are they actually worthy of being called hinges? All they are are strips of plastic paper.
Another problem occured on the ailerons as well as the elvator. The metal wires that go inseide them to move them (sorry about my lack of proper terms) appear to cut throught the foam and become loose, at the back of the plane the differnt sides of the elevator have differnet rates of movement. Should i have a pushrod going to each side?
As you can see, i'm a bit critical of foam planes, is there any way to add a shiny hard surface to the outside of one of the foam aircraft???? i don't want to admit to getting another one after what ive been saying about them recently.
Another issue, i intend to run it on a 10.8V 700maH li-on pack i have from my dragonfly heli but my speed controller does not have programmable functions. To avoid overdraining my batteries, (i may also use 2s 1500maH kokam li-po packs i have), mainly the 10.8V, how should i go about it? i have heard of people timing flights and my eclipse 7 is up to the task but i don't have the faintest clue how long i should fly for.
I have some GWS micro retracts( think they're micro, they are the blue ones) that are intended for the formosa.
Any help would be appreciated. For any newcomers, it's really not that bad even after what i said,
Thanks
Josh

PS. a picture of my beautiful A10 (needs better wheels!)

sorry, i didn't know the picture would turn out so large!

I have a GWS mustang and had similar issues as you did. This is what I found out:

Finish
There are many threads on "glassing" foam airplanes to add strength and a smoother finish. The down side is they add weight. If you have lots of power (brushless) and can handle higher landing speeds it's not that bad. Decide what you want - appearence or performance.

Hinges
The supplied GWS paper hinges are actually quite strong. I did unscientific destructive testing between them and Dubro nylon hinges and the GWS were stronger. The stiffness is most likely extra glue or too tight of clearence between surfaces. Try some oil or baby powder to loosen em up.

Foam control surfaces
These are parkflyers. I too was concerned about the unprecise nature of foam surfaces. Mostly, its not a big deal if the inboard side deflects more than the outboard. This prevents stripping micro servos anyway. Over time the foam will wear away and stretch where the control rod goes in (bad). Balsa is a feasible alternative for not much extra weight. I cut small spanwise slits and then insert CF strips which are then drilled to accept the control rods. So far so good.

The split elevator however is a BIG problem. In any type of load situation the elevator halves deflect different amounts which introduces a rolling moment which is VERY annoying. There are threads on how some have used dual control rods but that seems heavy. It needs to be stiffer but I have not solved that one yet.

Lipos are very sensitive to over discharge! I've toyed with the idea of timing flights on my non lipo freindly ESC's but have so far chickened out. I suppose one could use motor calc or similar and figure out the "normal" flight times for a particular setup and then decrease that by a bit to have a safe margin. Seems like a bit of an unacceptable risk to me for an expensive batt pack - but to each his own.
That 3s 700 Mah Lipo pack you mention won't sustain a very large amp draw either. I'm guessing under 6 amps continuous. That leaves a kinda marginal setup using a gearbox or prop combination to keeps the amps that low. The 2s pack may be a better bet even at the lower volts. You'll have to look it up for your setup.

http://www.parkflyermotors.com/secur...or%20Chart.xls

Hope that helps.

BTW I am not by any means an expert on this stuff.

Thats a great help, thanks
I'll certainly use your findings when building my formosa and if i discover a strong lightweight solution to the elevator problem i'll post it here.
I'm just going now to check out the motor/battery situation now, seems i will have to leave my 700maH in the draw for a while till i find a useful solution.
Thanks again,
Josh

You might try taking a small control rod (spring wire), bend it into a "U" shape with the curved part actually straight and attach one leg to one half of elevator, the middle next to the horizontal stab, the other leg onto the other half of the elevator. I just ca'd it to the park flier I built, but, you could press it into the foam elevator. Worked good for me.

Good luck

just a couple of questions regarding the motor/gear/prop chart.
Does a 10X8 prop just equal 10inch diametre, 8 inch pitch?? or is there something more complicated?
Also my batteries are kokam li-po 2 cell 1500maH, so what is the battery amps??? The only information on the battery was that it was "high discharge" which is not to useful.

You are correct on the prop. That is all it means. 10 in diameter and if it could drill into wood it would move 8 in. forward with one turn. I am not sure if that's what you meant by 8 in. pitch but, that is the way its labeled.

As for as the batteries, usually the amps is what you setup draws. i.e. size motor, prop, and maybe gear drive. The 1500 mah can be thought of as the gas tank. That's how much power it holds. The bigger the number, the more 'gas'. That number will not change power, only length of time of usage with a full battery. The amps are how much 'gas' your setup uses at a set period of time, say a little car gets 30 mpg and a large car getting 15 mpg. High discharge means you can have a setup that pulls a lot of amps and be able to get it from the battery. However, the more amps pulled, the less time in flight. An example it the speed 400 motor with direct drive and a properly matched prop will PULL about 10 amps or so. A speed 180 motor with or without gear drive pulls between 3 and 5 amps, I think. Others know a lot more about that part.

Hope that helps.

Agcatsbest I like your fuel tank analogy and think that is bang on for every other battery except Lipos. From what I've been told, most Lipo's are rated at around 8c with new ones handling 10c to even 12c. The meaning of that I am told is that a 10c 1500 mah lipo battery should be good for 15 amps continuous. 1000 mah for 10 amps and so on. Wire 2 10c 1500 mah packs in parallel and they can handle 30 amps! Apparently that was done with older Lipos before the amp draw ratings started to become useable.

That is consistent with the 3 GP Lipo packs that I have. I also tried drawing 12 amps once from a 3s 1200 mah pack that was rated at 9 amps continuous and my CC 25 ESC said no thank you. What CC said in email was that the voltage drop on Lipo's happens very quickly if you over draw them and the ESC was cutting out due low volts. Inadvertant saftey feature of that ESC I guess, but it saved me buring up a pack. After some digging I found that particular pack only rated to 8c or 9 amps continuous so I smartened up and propped down. Works fine now. Same plane etc but 1500 mah pack easily handles much bigger prop and amp draw. Pack is same make/product but 1500 mah and rated at 11 amps. So if that is correct, with Lipo's the bigger the tank - the more power you can get from them.

Ps always check the ratings of YOUR Lipo pack before cranking out the juice. That and I'm still no expert either. Pls correct me it I'm wrong

thanks hepdog, this was the information i was looking for, i think i''l attempt to find the exact value though as you suggested.
Thanks

OH, you certainly know more about li-po than I do! I didn't notice that was what he was asking about. However, I have, all my life, thought you could run any set of batteries parallel to increase amp's available along with increased 'gas'. I have been wrong many times in my life before! No reason not to be now!!

Are you using a li-po compatable ESC? If so, they are designed to shut off before the voltage gets too low to prevent damage. Regular ESC's do not shut off soon enough. You may very well know what you are doing and I don't mean to suggest otherwise, just that you mentioned the inadvertant safety feature of your ESC.[8D]

I'll leave well enough alone and see you later!

well, my current esc is not a specia lipo one as such, but it does have a cutoff at 4.8V which i think is the correct cutoff point for 2s li-po however, i realise my 3 cell would not be safe to use with this esc. I have thought of purchasing a better esc but the money just isnt there
Thanks

well, my current esc is not a specia lipo one as such, but it does have a cutoff at 4.8V which i think is the correct cutoff point for 2s li-po however, i realise my 3 cell would not be safe to use with this esc. I have thought of purchasing a better esc but the money just isnt there
Thanks

I have GWS beaver, Estarter, Mustang and formosa(not built)

I had this problem on some planes I fixed it by adding a slight strip of aluminum to the elevator. It is very easy to do and you can get it at Home depot or lows as roofing flashing. Glue on w/ a little epoxy and it eill be very tough. I also used this to correct problem with breaking rear stabs and horz stab. By bendinr small pieces at a 90degree angle and gluing down. If you have plenty of power, you'll never feel it.

Joe

Agcatsbest, np, maybe I didn't explain myself very well. I DO use a programable and Lipo safe ESC. The inadvertant saftey feature I was talking about wasn't just the ESC shutting down for soley low voltage, it was the ESC shutting down for low voltage BECAUSE of over drawing the amps. This can happen right of the charger. The point of it all is that Lipo's rated capacity in MaH and the rated discharge rate as a function of "C" appear directly related to how much power (AMPS) the battery pack can handle. Over drawing a Lipo in AMPS is every bit as damaging as going to low in voltage, or so I'm told. With Lipo's, unlike conventional batts, it appears you need to carefully match the batt to the application.

Got ya!! I think....[8D]

yes i had a simular problem, they ended up being a little harder to move than normal, but they eventualy losened up and are fine now.
With the elevator, i find the side not attached to the servo has a little to much free movment, so that side will not move as fare as the other side, should be an easy fix.
BTW, it still flyes well.