Ufdah's E-Starter Build - RC Groups
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Jun 12, 2012, 02:35 AM
If it aint broke, tweak it!
Ufdah's Avatar
Build Log

Ufdah's E-Starter Build


This build was a (successful) attempt to get back into RC with a couple goals:
  • Cheap
  • 4 Channel Trainer
  • Easy to fly with ongoing value after getting the basics down.
  • Kit that I could put my own electronics in so that they could be transplanted into future planes.
  • Stable low speed flight
  • Capable of basic aerobatics
  • EPO foam for resilience to dumb thumbs while reentering the hobby.
Now that the plane is done and I've put a couple hours on it I can say that I'm really happy with it's performance! The flight times are great, the handling is great, the build was easy, cost was low, parts are reusable, I think I successfully achieved all my goals. There is really only one thing that bugs me about the plane and that's the silly landing gear that it comes with, talk about bendy... but if that's the least of my issues then I'd say it's all good!

The EPO kits have been notoriously tail heavy and I only made it worse by using a super light motor but I was able to compensate for that by mounting all electronics as far forward as possible. When it was all said and done my C.G. was right on according to the factory marks on the wings and I didn't have to add any balance weight! For more about my C.G. mods see post #4.

As Built Specs:
AUW 1,000mAh 30C 3s: 16.8 oz
AUW 750mAh 20C 2s: 15.6 oz
AUW w/o battery: 13.9oz

Thrust with GWS 9050 DD Prop:
3S Thrust: 16.1oz
2S Thrust: 10.2oz

Power to Weight Ratio:
3S: 0.96:1
2S: 0.65:1

Flight Time on 3S: approximately 20 minutes with throttle management.


Parts List:
GWS ESTARTER - white, no power system
Hextronik 24g 1300KV Blue Wonder Motor
Hobby King 10A ESC Replaced because it was cutting out on me.
HURC 22 Amp Brushless Motor ESC
HK15178 servos x4 (one per aileron for flaperons)
Rhino 1050mAh 3S1P 30C Lipoly Pack
Rhino 750mAh 2S 20C (for ultra light flights...)
Turnigy 9x Transmitter
HK-T6A-V2 Receiver
GWS 9050 Prop
Stick Mount - for motors with 8mm bearing tube

----------------------------------------------------------------------------------------------
On with the build....
It's amazing how strong our sense of smell is... tonight I began building my GWS E-Starter NPS and when I started mixing the 5 minute epoxy I was immediately whisked away 20 years into my past remembering my first experience with epoxy, building my very first RC airplane. I only flew for that summer before I destroyed that little 1/2a plane and now here I am back for more! I'm stoked to get this guy built and in the air but hopefully I'll have the patience to do it right and maybe even document the process...

I'm planning to make this bird as light as I can, I really like the idea of being able to drop the flaps and just crawl through the air.

Tonight I got the push rod sleeves installed, 5min epoxied the CF wing support in place and used white gorilla glue to glue the fuselage together.
Last edited by Ufdah; Oct 25, 2012 at 12:14 PM. Reason: Updated As Built Specs
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Jun 12, 2012, 02:35 AM
If it aint broke, tweak it!
Ufdah's Avatar

Update #1


I've managed to get a little more work done on the plane. I cut out all the control surfaces and hinged them with the new supplied plastic hinges which really aren't all that bad. I'm fairly impressed with the ease of flexion and installation of them. I also smoothed out the body with a razor blade, cutting all the little stray pieces of glue and foam off. Then it was on to doing a little bit of soldering; midnight might not be the best time to start that project... As you can see from my first battery picture, I wasn't fully lucid.

One thing I did do was to open my servos, desolder the wires, cut off a couple extra inches from the two that will be in the fuselage and solder that as extensions into the aileron servo wires. I know that's kind of anal but to keep the weight down and still have individual aileron servos I chose this instead of using additional extension wires, plus it's cleaner not having the extra plugs in the wire. As you can see in the servo picture I staggered the three solder joints so that I don't have to heat shrink them. I'll embed the wires in the wing and run a piece of tape over it. I also took the aileron servo's mounting ears off to reduce their footprint and weight and cut a hole in the bottom of them so that the servo wires will have a straight shot out of the servo to the fuse.

I loosely put everything in place and held the plane to get an idea of the C.G. and I can tell that it's going to be difficult to get it far enough forward. With the 24g motor up front and the weight of the EPO foam I'm going to have to mount all electronics as far forward as I can to minimize additional balance weight. Battery will most definitely be going under the wing in the nose to help out... One benefit to this is that it will keep all my weight closer to the wing which should make it a little more nimble too.
Last edited by Ufdah; Jun 27, 2012 at 12:57 AM.
Jun 12, 2012, 02:36 AM
If it aint broke, tweak it!
Ufdah's Avatar

Update #2


The build continues! Glued the horizontal and vertical stabilizers on. To do the horizontal I turned the plane upside-down so that it would sit squarely on the table and elevated the tail until the H-stab was parallel to the table, then glued it and stacked some books on it. For the vertical I used a 90 piece of cardboard and taped it between the horizontal and vertical stabilizers in the hinge line as pictured to ensure that they were perpendicular.

Installed the landing gear, the back is stock, the front I drilled out the pegs in the plastic gear mount and ran toothpicks through it before gluing to stiffen things up a little. See picture.

I also managed to install the motor stick and mount. I found that in the manual it only calls for 20mm of stick in the fuselage and I have about 35mm so no problems there. The problem I did have was that I used white Gorilla Glue and walked away from it. The glue expanded so much that it came back through the center of the stick and got into the motor!!! It cleaned off pretty well but was a hassle non-the-less...

Ailerons are complete also. To get the C.G. a little further forward I mounted the servos closer to the leading edge than most do but it worked out with no problems. I have programmed my TX for flaperons and everything seems to be working correctly. More to come later!!!
Last edited by Ufdah; Jun 27, 2012 at 10:36 AM.
Jun 12, 2012, 02:37 AM
If it aint broke, tweak it!
Ufdah's Avatar

It FLYS!!!


I know it's taken me a while to update my build but I've been having too much fun actually FLYING my E-Starter! This thing really does fly great! Anyways more on that later, back to the build...

There are only a couple more things that I did differently than the stock setup. One was carving out another 1.5" of foam in the front of the battery compartment. This allows me to slide my 1000mAh 3S batteries further ahead of the C.G. to help with the excess tail weight from the EPO foam. You can see from the pictures that this helps both by giving a tunable C.G. with the battery and allows for more room for the connectors.

I also mounted the tail servo's up on the shelf about 2" forward of their stock location. This helped with the C.G. and also raised the weight up closer to the wing. The only thing about this is that the stock control rods are JUST long enough this way. I didn't cut them at all and was unable to even put Z-Bends in them, I had to use 90's with clasps on both end...

I also replaced the stock bolt and nut that hold the wing down. I really didn't like how fine the threads were and the little black piece that went on the wing was just ugly. I instead drilled things out a little and used a 1/4"x20x2" nylon screw and nut. The nut is just gorilla glued inside but I feel pretty good about it. It feels a lot more solid than the stock setup. (I did have it stock but decided to change it...)

One thing I don't like is how SOFT the landing gear is! If I land it with anything less than perfection one of the wheels gets tweaked. I know that I'll get better at this as time goes on but even just setting it in the car funny will bend it. The 2.5" wheels that I'm using are working great. It hasn't caught on anything or flipped on me yet and I have about 20 ROG takeoffs and landings. Not much ground clearance though with a 9x5 prop; if the grass is not SHORT then I'm mowing it...

I have control surface travel mechanically maxed out and I'm using 60% low rates to tame it down with 30% exponential. Then 100% high rates with 50% expo and it really snaps around pretty good. I'm surprised at how tight it will loop. The flaperon setup is also working well. I haven't gotten everything totally ironed out but I currently have flaperons set to 50% down aileron travel and I still have decent control over the plane anything over 50% and I started loosing control with the ailerons (more fine tuning to come...). I played with spoilerons and didn't really see any benefit to them, it just wanted to fall out of the sky...

All in all I'm VERY pleased with this as my first aileron plane. It really seems to handle well while still offering a good enough level of performance that I can see flying it for years to come!!!
Last edited by Ufdah; Jul 04, 2012 at 06:17 PM.
Jun 12, 2012, 02:52 AM
If it aint broke, tweak it!
Ufdah's Avatar
I've got two questions for any experienced e-starters out there.

1) Is 1.5" of motor mount stick in the foam enough? Where can I get a longer motor mount stick if I need to set it further back in?

2) When I received the plane it had some dings in the wings. Is there a way to get the EPO to pop back out or a lightweight way to fill the dings in?
Jun 12, 2012, 07:03 AM
Shelter Kitty "Orange Death"
bartricky's Avatar
A word of caution...

HK lists that motor as backordered (BK).

You may wait a long time for your order to be shipped if you include anything BK.
Jun 12, 2012, 07:29 AM
Just having fun
Fredriksson's Avatar
Nice choice on a plane. The GWS E-Starter is one of my favorite planes.

Something doesn't sound quite right in your power system. I think it is the prop size as compared to the motor and the ESC. That 9x5 prop might be a bit too much. the recommended prop is 8x3.8. Going up to a 9x5 prop might pull too many amps and overheat the motor or the ESC or both when running on 3S. The 9x5 prop might be OK on 2S but could still be approaching the 7.5A threshold. A watt meter would let you know what your system is pulling. However, on 2S at 7V and going max amps on the motor is only 52 watts. Your plane should come in around 21 oz. in weight. That would put the power at 40 watts/lb. Not very much power. Maxing out the amps to 7.5A with 3S would give a little over 80 watts which would be a little over 60 watts/lb. which is at least flyable.

As for the stick mount, if it is too long, rather than pushing it in further just cut off the end where you need it. I had to cut my stick down so that only about an inch is sticking out of the firewall in order to get the motor to lign up well with the shorter, old style E-Starter cowl.

As for repairing the foam, I believe that your E-Starter is the EPO foam. All of my E-Starters and other foam planes have been EPS foam. I have no experience with the EPO.

Good luck on the build. I will be watching for your posts showing your progress.

Freddy
Jun 12, 2012, 09:16 AM
CA...gimme the CA...
whowhatwhere's Avatar
Hi Ufdah, and welcome to world of E-Starters! As Fred says, a great flying plane. I'm very interested in your method of installing flaps.

C'mon over and join us in the Ultimate E-Starter thread....some cool folks there.

As to the dings in the wing, I have some lightweight balsa filler I use. Got a container of it and have been using it for years....a little goes a long way.

Ric
Jun 12, 2012, 11:32 AM
If it aint broke, tweak it!
Ufdah's Avatar
Quote:
Originally Posted by Fredriksson
Something doesn't sound quite right in your power system. I think it is the prop size as compared to the motor and the ESC. That 9x5 prop might be a bit too much. the recommended prop is 8x3.8. Going up to a 9x5 prop might pull too many amps and overheat the motor or the ESC or both when running on 3S. The 9x5 prop might be OK on 2S but could still be approaching the 7.5A threshold. A watt meter would let you know what your system is pulling. However, on 2S at 7V and going max amps on the motor is only 52 watts. Your plane should come in around 21 oz. in weight. That would put the power at 40 watts/lb. Not very much power. Maxing out the amps to 7.5A with 3S would give a little over 80 watts which would be a little over 60 watts/lb. which is at least flyable.

As for the stick mount, if it is too long, rather than pushing it in further just cut off the end where you need it. I had to cut my stick down so that only about an inch is sticking out of the firewall in order to get the motor to lign up well with the shorter, old style E-Starter cowl.

As for repairing the foam, I believe that your E-Starter is the EPO foam. All of my E-Starters and other foam planes have been EPS foam. I have no experience with the EPO.

Freddy
Thanks for the thorough feedback! Looking at the product reviews for the motor a number of people have tested the 9050 and claim that it draws between 6.6 and 9A with most claiming a draw of 7-7.2 at WOT on a 3S. The same reports claim 15 - 19oz of thrust.

Why are you thinking the plane will come in at 21oz? I was hoping for 15-17oz with the lightweight motor, minimal stickers, no paint, mounting the motor and battery as far forward to prevent adding weight for C.G. If all this works the way that my naive mind hopes that it will I'll end up with a power to weight ratio close to 1:1 which should be more than enough for my purposes of this plane.

I recognize that it would not be a good idea to run WOT with the 9050 for any significant lengths of time but I don't mind pushing the envelope a little either. My motto has always been: "If it aint broke, tweak it."

On the motor mount, my problem isn't that the stick it too long, I'm afraid that it's too short. I'll only have 1.5" of stick in the fuselage and I didn't know if that was enough...
Jun 12, 2012, 01:55 PM
If it aint broke, tweak it!
Ufdah's Avatar
Quote:
Originally Posted by whowhatwhere
Hi Ufdah, and welcome to world of E-Starters! As Fred says, a great flying plane. I'm very interested in your method of installing flaps.

C'mon over and join us in the Ultimate E-Starter thread....some cool folks there.

As to the dings in the wing, I have some lightweight balsa filler I use. Got a container of it and have been using it for years....a little goes a long way.

Ric
re: the flaps, I'm not actually doing separate flaps. I'm just programming flaperons into my transmitter and running a servo for each aileron...

Thanks for the tip on the filler I hadn't thought of that. I think I'll also try the water and hot iron tip listed here: https://www.rcgroups.com/forums/show...355#post614880
Last edited by Ufdah; Jun 12, 2012 at 02:39 PM.
Jun 12, 2012, 08:43 PM
Just having fun
Fredriksson's Avatar
Quote:
Originally Posted by Ufdah
Thanks for the thorough feedback! Looking at the product reviews for the motor a number of people have tested the 9050 and claim that it draws between 6.6 and 9A with most claiming a draw of 7-7.2 at WOT on a 3S. The same reports claim 15 - 19oz of thrust.

Why are you thinking the plane will come in at 21oz? I was hoping for 15-17oz with the lightweight motor, minimal stickers, no paint, mounting the motor and battery as far forward to prevent adding weight for C.G. If all this works the way that my naive mind hopes that it will I'll end up with a power to weight ratio close to 1:1 which should be more than enough for my purposes of this plane.

I recognize that it would not be a good idea to run WOT with the 9050 for any significant lengths of time but I don't mind pushing the envelope a little either. My motto has always been: "If it aint broke, tweak it."

On the motor mount, my problem isn't that the stick it too long, I'm afraid that it's too short. I'll only have 1.5" of stick in the fuselage and I didn't know if that was enough...
Perhaps I am wrong. It sounds like you have done your research. It just sounds like a small motor to be turning a 9" prop. Even the HobbyKing website says that 3S LiPo on this motor with a 8x3.8 prop will give 14 oz. of thrust. And, the data shown here is similar to what you are stating on a motor very close or maybe the same as the motor you have. It will be interesting to see how the power system performs in your application.

As for weight, if your E-Starter is pretty newly purchased it is made of EPO foam. The EPO weighs more than the EPS foam. I know that in the past those with really light EPS foam E-Starters claimed a weight of 16 oz. or so. With the heavier EPO foam, your finished weight may be a little ambitious. But, again, it will be interesting to see what you end up with.

As for the depth of the motor mount stick being strong enough, I have only had one break loose and that plane took a really hard nose in. I did glue it back in. Short of a hard nose in, the strength should be sufficient.

So, while you build your plane fix me up a serving of crow. I just may have to eat it. In the mean time I will keep an eye on this build log see how things go. If you are able to meet your goals you will have one really sweet plane. I will be envious.

Freddy
Jun 12, 2012, 11:26 PM
Registered User
Ufdah,

I'd recommend using an ESC with 15 - 20A rating instead if you would like to use prop 9 x 5 and 3S lipo. THis way would be safer and helpful when you have to apply WOT longer, or you forgot to throttle down right after any possible crash, or you'd use a bigger motor instead some day.

Applying boiling water on the dings could help pops them back, but you have to be careful with the hot water. Also be reminded that the EPO Estarter is heavier than the EPS one by almost 20% of weight, so I normally suggest my buddies using 400 size 1000KV motor on it.

Chen
Jun 13, 2012, 12:22 AM
CA...gimme the CA...
whowhatwhere's Avatar
Mine came in at 21oz, although you may be able to keep it light. But...I wouldn't be surprised if it ends up somewhere between 17-20oz. I would go with something rated for that weight, and if it's a bit lighter it'll be fun!
Jun 13, 2012, 01:13 AM
If it aint broke, tweak it!
Ufdah's Avatar
Thanks guys! Sounds like I might be a little ambitious with the weight... Didn't realize the EPO was that much heavier. I took the tape off the fuse tonight and everything looks good. Definitely have a LOT of sanding to do; this guy is pretty rough around the edges...

Oh and Fredriksson, that is the same motor.
Last edited by Ufdah; Jun 13, 2012 at 01:19 AM.
Jun 13, 2012, 09:11 AM
CA...gimme the CA...
whowhatwhere's Avatar
Don't trust the wing connector! I beefed up mine *substantially*...especially after ripping the wing off mid-flight.

For the fuse connector, I drill a hole for a #4 wood screw in the center of the plastic connector. Then I counter sink the hole BY HAND with a drill bit so the screw head will sit flush. Using a drill it's very easy to screw up, it'll drill right through it. Drill a large pilot hole in the fuse and glue on the connector using a 1'' #4 wood screw, with a good dose of Gorilla Glue on the threads. You want a large pilot hole in the fuse for the glue to expand into. Once it sets it will never come out.

Attach the wing connector per instructions, then carefully shave off the tabs and drill out the holes, being mindful to ensure the holes are exactly where they should be. Then replace the tabs with bamboo skewers, at least 1.5" into the wing, while leaving approx. 1/2" on the outside for the joining tabs. I drill into the wing and use Gorilla Glue to set the skewers....once again, when it sets it won't come off.


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