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Mar 16, 2016, 12:07 PM
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NewZee's Avatar
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SIG "WONDER", conversion to Electric power & battery hatch modification!!


Hi All,

This topic has been covered before (E-Conversion) of the SIG Wonder, ... But I'm doing it now and wanted to document my progress, I didn't want to hijack one of the older SIG Wonder threads!!!

I'll posts lots of pictures, and videos, and will try and explain my choices as far as power set up, and modifications such as extending the nose, and designing a top loading battery hatch!!

I hope you'll follow along, and offer constructive criticisms!!

I won't start the build in earnest for a few weeks (As I finish up a current "Slow Poke" build, but to get things started here are a few pics of some sweet looking "E-Wonders" that will serve as my inspiration!!
Last edited by NewZee; Mar 16, 2016 at 01:07 PM.
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Mar 16, 2016, 12:54 PM
Foam is my friend!!!
NewZee's Avatar
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Preliminary "top Loading" battery hatch


Hi All,

Haven't even started the build yet (and won't for a few weeks)! but I have laid out a preliminary design for the top loading battery hatch! see my rough sketch below!

the hatch will be secured with pins. magnets, or latch and will allow install of up to a 2200 mAh 4s battery pretty easily!

still not sure if I'll extend the nose or not?
Mar 16, 2016, 05:42 PM
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numb_thumbs's Avatar
So if I read your drawing right you will have a top front hatch to slide the battery up under the wing, correct?

I found on the one I built a few years ago that a 3C 2200 battery moving a 1/4 of inch was enough to totally screw your CG. Most planes have a CG *range*. The wonder has a CG *point*

So the problem I had was having enough 'wiggle room' to get the batt in and out while at the same time making sure it was in EXACTLY the same place every time. One time it shifted that 1/4 inch in flight and it went so tail heavy I just barely got it on the ground in one piece!

I think if I had it to do again since there no landing gear is just go belly hatch
Mar 16, 2016, 06:19 PM
Foam is my friend!!!
NewZee's Avatar
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Quote:
Originally Posted by numb_thumbs
So if I read your drawing right you will have a top front hatch to slide the battery up under the wing, correct?

I found on the one I built a few years ago that a 3C 2200 battery moving a 1/4 of inch was enough to totally screw your CG. Most planes have a CG *range*. The wonder has a CG *point*

So the problem I had was having enough 'wiggle room' to get the batt in and out while at the same time making sure it was in EXACTLY the same place every time. One time it shifted that 1/4 inch in flight and it went so tail heavy I just barely got it on the ground in one piece!

I think if I had it to do again since there no landing gear is just go belly hatch
Thanks for the feedback! You make some good points, and I can't argue with what your saying since you have the firsthand experience!! I had other "bottom loader" airplanes and always hated them! I've lost batteries in flight, and even under the best of circumstances the Vert stabilizer takes a lot of abuse when the plane is upside-down changing batteries! I'll install a "hard stop" on the battery tray to locate the battery on the right CG point. And I always "Velcro" the batts in place. Wouldn't the battery have the same propensity to shift with a bottom hatch? my big question at this time is will I be able to get the battery into the right position (under the wing) through a relatively small access hatch?
Mar 16, 2016, 06:50 PM
I just want to go fly!
walter3rd's Avatar
I guess the key is to somehow know the CG and have a wood batt stop like you mention to keep it from shifting rearward and lots of Velcro to keep it from shifting forward but I can't see it going forward as the sucker will be going 150 mph!
Mar 16, 2016, 07:54 PM
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NewZee's Avatar
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Quote:
Originally Posted by walter3rd
I guess the key is to somehow know the CG and have a wood batt stop like you mention to keep it from shifting rearward and lots of Velcro to keep it from shifting forward but I can't see it going forward as the sucker will be going 150 mph!
For sure, I'll build the wing and fuse (less hatch) and then check CG balance with the motor, spinner, prop, ESC, & battery in place, Once that's done I'll cut the hatch, still would like the option of 3S (slower) and 4S (faster), and want a little "adjustability"
Mar 16, 2016, 10:05 PM
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Aviron's Avatar
I keep saying to myself that if I enclose the nose it'll go faster. But I'm also lazy!

I definitely agree that CG is extremely sensitive. 1/4" the wrong way and you'll have to change your shorts. I used the good'ol finger tip method to set mine up for the maiden. That flight was terrifying. I have never flown anything that sensitive and messed up. Thankfully, got it down in one piece. After 20 years, I finally built a CG stand with more precision than my fingertips.

Mine is setup so the prop is where shown on the plans. That's why the long stand-offs. Using 3s-2200's, the pack ends butted up against the firewall. It's still touchy as all heck on the elevator. I could probably stand to move it forward a smidge more.

And... no hatch on mine. Big oversight. Removing the wing is a big PITA.

I have broken the fins off a few times on some less than stellar landings in longer grass. I ended up "pinning" them in. I drilled some toothpick diameter holes in the fins lined up with the stab and then slid them in with some slow glue.
Mar 17, 2016, 06:14 AM
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numb_thumbs's Avatar
QUOTE=NewZee;34278209x, and even under the best of circumstances the Vert stabilizer takes a lot of abuse when the plane is upside-down changing batteries![/QUOTE]


Yeah, I *HATE* bottom hatches!

It just now occurred to me the slide out nose concept is probably the best way to go with a Wonder!

Like so!

https://www.rcgroups.com/forums/show....php?t=2358520
Mar 17, 2016, 07:17 AM
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NewZee's Avatar
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Quote:
Originally Posted by numb_thumbs
QUOTE=NewZee;34278209x, and even under the best of circumstances the Vert stabilizer takes a lot of abuse when the plane is upside-down changing batteries!

Yeah, I *HATE* bottom hatches!

It just now occurred to me the slide out nose concept is probably the best way to go with a Wonder!

Like so!

https://www.rcgroups.com/forums/show....php?t=2358520[/QUOTE]
Very interesting, and certainly a unique solution!! I'm hopeful I can noodle out a workable top loading hatch, but the slide out nose could be an option!
Mar 17, 2016, 07:21 AM
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NewZee's Avatar
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Quote:
Originally Posted by Aviron
I keep saying to myself that if I enclose the nose it'll go faster. But I'm also lazy!

....., the pack ends butted up against the firewall. It's still touchy as all heck on the elevator. I could probably stand to move it forward a smidge more.

And... no hatch on mine. Big oversight. Removing the wing is a big PITA.

.........
Well if you build a nose the additional nose weight, might let you move the battery a tad further back, and improve balance?? it's still a nice looking bird! are you running "Expo" on the elevator? if so, how much?
Mar 17, 2016, 10:02 AM
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Aviron's Avatar
I look at it on my airplane rack daily and think, "I should enclose that nose..." then get distracted.

I have about 40% expo on the elevator and the throw is 3/16". When they spec the rates PAY attention.
Mar 17, 2016, 11:17 AM
Foam is my friend!!!
NewZee's Avatar
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Quote:
Originally Posted by Aviron
I look at it on my airplane rack daily and think, "I should enclose that nose..." then get distracted.

I have about 40% expo on the elevator and the throw is 3/16". When they spec the rates PAY attention.
Thanks!!! ...The reason I'm building the "Wonder" is that I love the flying "style" of my foamie "Wingnetic" and DTFB "Funbat" both are based on the wonder design, and both fly with a fair amount of expo (60% on the wingnetic)!!! love the fact that they can be thrown in the car and flying on short notice!! both fast & very acrobatic!!!

I hope the "Wonder" acts similarly, but holds up a little better than the DTFB Funbat, and the weak nosed Wingnetic!!
Mar 17, 2016, 09:50 PM
Really?!?
ChrisS's Avatar
When I built mine, I couldn't see a better way to build a hatch than to do it on the bottom. What I did was to incorporate the skid into the hatch with a mounting that incorporates a tongue and groove at the front and a pair of magnets at the rear of the skid. It has worked well and never come off during a landing.

Fairing in the nose, for me, was also the only way. This design screams to be streamlined, any other way would have been a sin.

Chris

*Oh yeah, use a bunch of expo (I use 40%) and DO NOT think you'll be clever and add flapperons with a conventional (downward) offset...unless you like changing your shorts in the middle of the day. Flying wing rules apply.
Last edited by ChrisS; Mar 17, 2016 at 09:59 PM.
Mar 18, 2016, 06:29 AM
Registered User
numb_thumbs's Avatar
Well I don't know why I did not think of this sooner.

Here is the solution that was created to address exactly this problem- - the battery had to be beneath wing but builder HATES bottom hatches or taking off the wing! This worked VERY well!

https://www.rcgroups.com/forums/show....php?t=2056041
Mar 18, 2016, 06:46 AM
I just want to go fly!
walter3rd's Avatar
clever


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