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Old Dec 28, 2008, 05:04 PM
Fly, dangit!!!
Led Zepplin's Avatar
Little Rock, AR USA
Joined Jan 2007
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Guillows Warbird Conversion

So, like most folks around here I've got several irons in the fire that I need to finish... but, I got these for Christmas and I've sort of been looking to build something a little bigger that can be flown outside in a little bit more wind. I've been researching a ton of threads on Guillows conversions and tried to follow most of PC's 170 conversion, but I'm definitely going to need plenty of suggestions! Out of these 4, I'm leaning towards trying the Hellcat first because of the simple fuse shape and the relatively large WA. I also like it because of the midwing configuration in that there won't be a lot of complicated fairings to figure out.

The recurring theme that I keep hearing is to replace either most or all the wood with better, lighter balsa, so I'm planning on that. I'm thinking of covering it with Durobatics. Right now I'm thinking that I'll build the frame and then make some paper templates to get the shapes of the covering down. If I use thin sheet foam as a covering, that should let me delete half the stringers since I'll get some rigidity from the foam.

As for electronics, I have quite a bit of Plantraco gear so I was also thinking of using their servo Rx, but with only 3 channel. I was thinking of trying the Hobbycity 5g brushless motor with a MicroInvent 3 blade 4335 CF. Anyone with more experience with that motor think that it would swing a prop that big? Also, I wasn't sure if that would be too much current for the 1g Turnigy ESC, or if I would need to use the 6A ESC. As for servos, I was thinking either the 2.5g Blue Arrows or the 1g Toki ones.

Assuming worst case, if all these parts play nice with one another, that brings the weight of the electronics to somewhere around 25g. I found this link in some threads on the forum of a series 500 Guillows Hellcat that was converted to RC with an AUW of 4oz, or about 113g. I was hoping that I could pull it off with about half that weight, but here's for hoping!

Any suggestions on any of these assumptions are appreciated!
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Old Dec 28, 2008, 05:25 PM
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foxsavage's Avatar
Castro Valley, CA
Joined Nov 2007
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I think you'll have to go with the 6 amp esc because the 1 gram Turnigy is for 1 cell only. I know the 6 amp esc can be considrably lightened by using thinner guage wire. I'm not sure the Toki's would be powerfull enough unless you can get the weight down to around 60 grams.
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Old Dec 28, 2008, 05:54 PM
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RNAF's Avatar
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I've done a conversion of a 16,5" P-40. Built it really light using only 1mm thick balsa and mostly 4mm thick formers (thickness as seen from the front of the fuselage). RTF weight including detailing but excluding paint and dope is a wee bit under 20 grams. Flies fine with Plantraco deluxe starterset equipment and a carbon 5080 prop, but is a bit underpowered. I'm quite sure a 2 gram brushless on 1 cell lipo will do more than fine.
I wanted to go brushless too, but the RX can't be modified for such.

Make sure you get some amount of wash-out at the tips, mine hasn't and tends to tip-stall. Also 2 degrees downthrust is a good starting point, side thrust depends on how much torque your motor of choice has.

Go for it, my conversion is one of the best projects I've finished ever.
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Old Dec 28, 2008, 05:55 PM
Playing with AutoCAD!
PiperCub49's Avatar
United States, ME
Joined Oct 2008
2,648 Posts
It seems that the more I get through my build, the more I find that people are watching.

I see no problems other than those already pointed out by foxsavage, but then again I am a beginner.

I'll be watching!,
PC49
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Old Dec 28, 2008, 06:01 PM
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Before I forget:
1x1 mm stringers + standard tissue covering makes the plane really rigid. I even did not use some stringers to save weight. Indeed, do use your own balsa wood. I wouldn't use durobatics.

Take a look at my thread on the P-40: http://www.rcgroups.com/forums/showthread.php?t=900048
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Old Dec 28, 2008, 07:21 PM
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Midland, Tx / W. Lafayette, Ind.
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I was bored and bought a Hellcat kit a few days ago, they were 30% off. The Hellcat seemed to me to be the best candidate for RC in the aisle at Hobby Lobby, with the mid-wing and larger chord and less structural detail. The wood in my kit was pretty bad, but I haven't got the initiative yet to begin a build. If I were to go about it, I would replace all of the wood and eliminate some parts I found unnecesary.
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Old Dec 28, 2008, 09:30 PM
Fly, dangit!!!
Led Zepplin's Avatar
Little Rock, AR USA
Joined Jan 2007
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RNAF - I remember seeing your P40, that is a really nice looking plane! I had read it back when you posted it, but I had forgotten how light you were able to build it! Did you ever use a dope on the tissue? The main reason I was thinking of using the Durobatics is so I could coat it with Inkaid and print the graphics onto the foam.

If I used the Toki servos and went to the 2g brushless, I could save quite a bit in the electronics. I think if I went that route I could keep the AUW under 60g. The only thing with that is, I'd really like to have more of a scale looking prop, does anyone have a feel for how big of a prop the Hobbycity 2g brushless can swing? I wonder if it could swing that MicroInvent 4335 3 blade... I also have a venom 3 blade, but it looks pretty small for this scale.
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Old Dec 29, 2008, 12:11 AM
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Beijing, China
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The 2g motors are designed for a 3" prop. It has enough power for this size plane, but the nose might be too big for that prop to work well.

The 7A ESC is around 1.5g with all the wires stripped. They should also be available in 1 cell configuration; the manufacturer makes one. I don't know if HC carries them.

Another option is a 4,500 kV 5g motor, which will run on one cell. The small ESC is rated at 3A, 4A burst, so should be fine for this motor.

Keep in mind the fuselage was designed to take the stress of a rubber band. You can lighten it quite a bit.
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Old Dec 29, 2008, 03:53 AM
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Heliman420's Avatar
Canada, BC, Whistler
Joined Jun 2006
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go for it led! i love seeing these guillows warbird conversions!!!

i used to build these guillows warbirds for FF in my childhood and teens... some taking months too complete.. due too to much detail ... i built mine for FF power by rubber or a cox 010 or 020.. me and my father must have built 100 of them in a 10 year period....although 70% never got past the test flight.. and ended up in a thousand toothpick like pieces

since those days ive witnessed the arrival of small and cheap rc equipment making these builds perfect for micro rc... and have drooled at some of the conversions people have made


and i have been tempted to build another one.... but it looks as though ive been spoiled by depron, blue foam and durobatics... and have given up alltogether on balsa and tissue builds

but seeing threads like this makes me think about trying another guillows build in the future!

will be looking forward to your build.
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Old Dec 29, 2008, 06:30 AM
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Led, I never used dope or paint yet. Just because it'll add some grams. Also, the standard grey Japanese tissue gives it some authentic look like in old pictures. I do feel that at least the wing should be doped, just to fix some wash-out.
At this time the project is exactly at the point of my last reply in my thread. Just because it can not handle any wind to be honest. Really a gymflier. Also, other current projects need a lot of time.
Regarding the durobatics, you'd probably need 4-5 sheets of the thinnest type (.6mm). Each sheet is about 3,8 grams I've read, so you'd add approx. 15 to 19 grams excluding ink. It's your decision of course, trying won't hurt. Personally I'd go for the stock tissue.

Reylf, I didn't know about the prop dia., maybe with a larger gearing it'll work. The cowlings are large indeed. If the plane's going to weigh about 60 grams I wouldn't bother saving those 3 grams and go for a slighly bigger motor that can handle a scale prop.
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Old Dec 29, 2008, 09:17 AM
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United States, MI, Temperance
Joined Sep 2002
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I agree. Toss the kit wood. Toss the kit tissue too and use Esaki Jap tissue. It is loads easier to work with and worth the extra expense if you are going to invest the labor needed for a dope and tissue job. Once you have used both "domestic" tissue and Esaki, you won't even consider using domestic tissue again.
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Old Dec 29, 2008, 03:07 PM
Fly, dangit!!!
Led Zepplin's Avatar
Little Rock, AR USA
Joined Jan 2007
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Hmmm, It would be nice to be able to use that 4.6g brushless with the larger prop, especially if I could get by with a single cell battery and the lighter 1g ESC. BSD has a single cell 130 and 200 mah, I'd just need to add the connectors. Would that 130 or 200 be enough to push that motor and prop setup?

As for the covering, I'm still not decided, I did a quick rough estimation and I think I could cover it with Durobatics and only add about 8 to 10g including ink. I really have no idea about how much the bare frame will weigh, but I did get some better balsa today to replace some of the parts. I'm planning on scanning the plans and redrafting the parts to cut out what I don't need.

On that note, I've been studying the wing design and I'm thinking I'll definitely delete half the wing ribs. It's also calling for three 1/16" spars and a 1/16" x 7/16" LE and TE. I'm thinking of deleting the bottom spar, and replacing the upper ones with 0.04" CF rod. I also think the TE could be cut in half and I got some 1/8" stock for the LE so I'll make it narrow but thicker so that I can get more of a rolled front edge. Also, how much washout should I plan for? From what I've read, it sounds like I need to raise the TE of the wingtip about 3/16", does that sound about right?
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Old Dec 29, 2008, 03:34 PM
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Led, I think you'd do right searching this forum for comparable models in regard to weight and propulsion. There are a lot of different ways to convert your little fighter, but usually there is some "standard". I found Gordon Johnson's site very helpful so far.

As Tim also said, Esaki works really well and when lightly doped/ painted I believe it'll add less than half the weight of Durobatics to your bare frame. In my previously mentioned thread you can see a pretty elaborate overview of the weight of main parts. Sure enough, due to heavier equipment you'll be using, your frame will and should be a bit heavier.

As for wash-out, 3/16" should be enough. Someone else might want to share his view on this here. About the leading- and trailingedge: I used 1x4mm strips. 1,5x5mm strips would be more ideal. Just carbon rod on top of the wing won't cut it. For rigidness you should have at least one strip (balsa) or rod (carbon) underneath a top stringer, preferably near CoG.

Have you also thought about using a Parkzone 3ch RX? If you already have a Spektrum TX it might make a cheap and reliable combo.
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Old Dec 29, 2008, 03:44 PM
Fly, dangit!!!
Led Zepplin's Avatar
Little Rock, AR USA
Joined Jan 2007
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Another question, sorry I'm such a noob, hopefully I'll be able to contribute something to help someone else someday!

Anyway, this is will be my first BL model, is there anything that I need to know about hooking the motor and ESC up to the Plantraco Rx? Does anyone have a diagram of how this works? I can solder connections if I need to, but I was hoping that I could just plug everything up. I just wanted to make sure I ordered all the parts that I needed for this model all at once if possible.
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Old Dec 29, 2008, 04:02 PM
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Rockford Illinois
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Go for it! I did the hellcat this summer using the 5g hobby city brushless, 6 amp esc, and 2- 3.7g blue arrow servos. It was a bit hefty because I was stubborn and used the supplied wood, but it did fly. Lighten it up a little with 2.5 gram servos and be sure to shave weight on the air frame. Don't scrimp on the wing attachments though, you may need some extra reinforcement there.

I'm planning on trying out that P-51 sometime soon too. That seems to be a lot lighter than the 500 series. I also have the typhoon waiting for a rainy day.
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