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Old Mar 05, 2003, 10:55 PM
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Ragnar's Avatar
Near Mallala, South Oz
Joined Nov 2001
161 Posts
Baby Bf 110: Mega Success!

I just have to share this one. I had a freebie magazine plan from a couple of years ago: Chris Golds' Bf 110 for a pair of .020 slimers. I thought eminently suited to electrifying. I had decided to try a pair of 280's figuring lighter battery pack than using 400's, keep it light (Rule #1 for electrics) original was 17 oz all up, blue-foam wing, nacelles, and fus top and bottom, 1/16" sheet sides. The only major mods I did were to make the nacelles one piece, (No firwall, directly glue motors in.) and to fit a battery compartment floor from cross-grain 1/8" balsa. I also fitted undercarriage, as I like R.O.G. All of this led to its first appearence shortly after Christmas still unpainted, to cries of "under-powered!" and "Stick 400's in it!" Well, its maiden flight with 600 NiMHs was a gutless affair, and I almost beleived the critisism! But I thought I'd try to get some more "grunt" from NiCads. I'd test run the motors at home (2 x GWS 280's with the GWS 4.5x4 push-on props.) and was amazed that they pulled almost 10 Amps! Now what a difference! It taxied about 4', lifted the tail, was airborne in another 4' and climbed away at about 40 degrees! Lots of jaws hanging open! Cheif test pilot Dan (my son) did one quick circuit, then landed. I asked him what was the matter, he replied he needed to land to stop his knees rattling!
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Old Mar 05, 2003, 11:15 PM
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Ragnar's Avatar
Near Mallala, South Oz
Joined Nov 2001
161 Posts
I nearly forgot another mod to Chris' plan, was to remove the "out-thrust" on the motors, as I figured the chances of losing one motor was zero on an electric, it would be all-or-none. How wrong was I! It flew great for the first couple of weeks, then threw a prop off on take-off: cartwheel: broken fin: no-probs, fix and fly. CA prop adapter on. Next flight same thing! Replace 2.3mm spinners with the 2mm ones that came with the motors. A couple of flights same deal. Right I says, we'll use the 1.5mm ones jammed on with CA, and wait 24hrs for it to harden! That brings us to last weekend. A friend wanted to see it prop-hang, which it did pre-prop problems, so the lad took-off as usual up in about 8ft, pulled into a step climb, turned for the down-wind leg, still gaining height (for the beat-up I knew he was going to do) when it sort of "twitched' and he needed to put in a couple of click of aileron trim. We figured it was the slope lift form the hill over that side of the field. Then the beat-up seemed to be a bit slower. That was when Dan and I both noticed one prop gone! So even on one motor it flew fine! Gotta love those little GWS 280's, they seem to be a lot "hotter" than any of the others I've got kicking around.
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Old Mar 06, 2003, 07:01 AM
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Central Coast, Australia
Joined Jan 2001
1,026 Posts
that is ****** language edited by moderator awsom!!!!!!!!!

just gave me an idea..thanks

Jeremy..

Edited by Brian Cullen on Mar 07, 2003 at 10:21AM
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Old Mar 06, 2003, 07:56 AM
Now in TN!
J Morgan's Avatar
Chapel Hill, TN USA
Joined Apr 2001
24,709 Posts
Beautiful plane. Can you tell me what month and year and which mag it was in? Thanks.
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Old Mar 06, 2003, 11:13 AM
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DesignGeek's Avatar
United States, MI, Wixom
Joined Jun 2002
763 Posts
nice plane!

I've been kicking around several ideas for a foamie bomber of my own, And was considering 280's as you did. as they certainly are light-weight in a direct drive application. What is you wing span? and what size NiCds did you end up running?

How fast do you think it is flat out and will it cruise at a low throttle setting? I am considering doing a B-25 Mitchell an am a bit concerned that those little props will not be very effective in front of the B-25's big radial cowlings.

Also, the push-on/fly-off prop thing...do they make a threaded adapter for those GWS 280's?

Great job, lets see some more detail shots!

Cheers,

Rob
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Old Mar 06, 2003, 06:43 PM
Oz Member
Ragnar's Avatar
Near Mallala, South Oz
Joined Nov 2001
161 Posts
J. Morgan: I'll take a look, be back with that info soon.
Rob: The span is about 41" or 1040mm. All up weight less battery 16 oz or 500g. I started using an 8 cell pack of NiCad AA 600's, which worked fine. Last week we tried 8 cell CP1200 sized Nicads (from a cordless drill) figuring that it heaps of power to drag the bigger pack around. Just needed a bit more "hollowing" of the canopy. Still flew great. (In fact that's when it flew on one motor!)
I have just got 2mm Graupner prop adapters with the 2 grub-screws so that should end the prop coming off dramas. The GWS motors have a series of ridges on the shaft (supposedly to hold on the rubber spinner) which have to be removed to fit the Graupner adapters. This is easily achieved by running the motors up, and holding a flat file against the shaft, until the ridges are removed, constantly checking to see when the adapter fits, so you dont file too much. And here are some "under construction" photos. Most are self evident, but I'll throw in some comments as needed.
1st photo shows fus construction: 1/16" sheet sides blue-foam top, 1/8" crossgrain battery floor. Blue-foam wing with balsa LE and TE, full width strip ailerons, and two 1/8" ply dihedral braces/spars. Blue-foam nacelles. Aileron and elevator servos mounted.
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Old Mar 06, 2003, 07:05 PM
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Ragnar's Avatar
Near Mallala, South Oz
Joined Nov 2001
161 Posts
Here's a shot of the internal elevator link. The original plan called for just one elevator on one side, but I decided, if for no other reason than it looked better, to go for both.
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Old Mar 06, 2003, 07:09 PM
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Ragnar's Avatar
Near Mallala, South Oz
Joined Nov 2001
161 Posts
Nearly finished, with the canopy removed to show heavy wiring from motors coming out from wing, Rx held in with velcro, and with GWS 10A ESC, which ended up not "cutting the mustard" and being replaced with a 400 rondo type I had kicking around.
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Old Mar 06, 2003, 07:24 PM
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Ragnar's Avatar
Near Mallala, South Oz
Joined Nov 2001
161 Posts
Her's an under view showing the 1/16" ply landing gear spar, and the back half of the nacelles removed to get them on. Later the bits were stuck back on. The lower fuselage foam blocks yet to be fitted, including the bit over the wing. You can just see the 1/4" dowel going into the front former, but can't quite see the 3mm socket head retaining bolts at the back, on that ply strengthener. (Mind you, I've never taken the wings off yet, 'cause it's small enough to fit in the car assembled.) Note also I openned up the chin radiators to allow the out flow of hot air from the motors. The idea of simply gluing them in with hot-melt glue, means maximum air inlet, and I aligned the outlet near the brushes with the chin radiator.
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Old Mar 06, 2003, 07:33 PM
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Ragnar's Avatar
Near Mallala, South Oz
Joined Nov 2001
161 Posts
Last one for now. This is a shot of the Shulz rondo ESC, and heavier wiring since the GWS unit got a tad warm and melted the connectors on it. You can also see the carved blue-foam carb intake, and just see the (brown) carved balsa exhaust stacks. The aircraft was covered with tissue and PVA, but I got more wrickles than you can poke a stick at. (Luckily they don't show in the photos, and certainly not when its flying!) Next time I'll go pack to brown paper, may be a tad heavier, but covers nicely, but hey, I had to give it a whirl.
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Old Mar 07, 2003, 08:42 AM
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United States, MI, Wixom
Joined Jun 2002
763 Posts
Thanks for the detail. A nice model of an interesting subject.
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Old Mar 07, 2003, 10:04 AM
RPV builder & operator
Pierre Audette's Avatar
Canada, QC, Gatineau
Joined Jan 2001
2,303 Posts
I've got a twin with some generic S280 that has sufficient power on 7x600AE, but I also have a pair of Graupner S300 7.2V (GR7302), such as those used in their mini Piper. Any idea how these compared to the GWS S280 motors?
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Old Mar 07, 2003, 02:57 PM
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Irvine, Calif USA
Joined Feb 1999
12,177 Posts
Very nice Ragnar, I love it !!
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Old Mar 07, 2003, 07:57 PM
Registered User
Adelaide, SA, Australia
Joined Dec 2000
8 Posts
Pierre,
I believe that the Grupner 300 would be about the same. I initially used the GWS 4.5 x 4 props and the current draw was 4.8A per motor static. so if the Graupner jobs pull about the same then your in the ball park. The GWS dd 280's are much "hotter" than their gearbox jobs, heaps more pull. I've now got the Graupner adapters, and tomorrow I'll try them with Cox three bladed 5 x 3 props. See pic below!
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Old Mar 08, 2003, 08:58 AM
IAD
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New England, USA
Joined Nov 2002
3,742 Posts
You really get that much power out of the GWS-280s?? Wow!

Now, my trademark question: How much wing area?



~Luke
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