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Old Oct 21, 2003, 07:45 PM
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Palo Alto, California, United States
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Guillows FW-190 17" Conversion

I've converted many of the Guillows 24" kits (WWI & WWII) to RC and powered them with PAW 0.03 diesel engines, but never tried an electric conversion before. I started reading this list a week ago and have been very impressed with the quality of the models presented here, so I had some motivation to try.

Coincedentally, I had placed a bid on Ebay for what I believed to be a 27" span Guillows FW-190 kit, but it turned out to be a very old 17" version that was packaged with the same box-art as the larger one. I won the auction ($9, same price as a new kit) and decided to try building it as a 3 channel electric RC.

The model weighs 3 ounces prior to adding any color finish and is powered by a GWS 7.2 v motor (CN12-121 ?) and 2 Kokam 250 mah Li-Po cells in series. I'm using the GWS EP 3020 propeller direct drive, Cirrus 5.4 gram servos for elevator and aileron control, and a GWS receiver. I covered the plane in Japanese tissue with 2 coats of clear dope. I'll paint it with acrylic paints soon.

The plane flies fine, although it may be a little tail heavy. The aileron throw is only 1/8 inch and could be increased. At low speeds there is noticeable adverse yaw which begs for a moveable (or enlarged) rudder. The plane climbs with authority and can loop easily and roll acceptably. It is still a handful to fly, being so small and fast, but it does look good in the air even without painting. I don't have a duration estimate yet, my brain gets tired before the batteries do.

Steve Morris
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Old Oct 21, 2003, 08:55 PM
Big gov never Works
St. Martin's Avatar
Skunk Water, Rhode Island
Joined Jul 2002
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Nice work, Steve.

I believe your adverse yaw to be amplified by the tail-heaviness.

These small guillow's need to be balanced around 22%MAC, which is usually just ahead of the plan location for F.F.

Adjust the CG, and i'm sure it will perform better.

Steve
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Old Oct 22, 2003, 01:08 AM
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Palo Alto, California, United States
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Here is the plane painted. I added 1/4 ounce of lead to the nose following Steve's suggestion and I'll fly again tomorrow. All up weight is now 3.4 ounces.


Steve Morris
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Old Oct 22, 2003, 10:32 AM
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ATA Flyer's Avatar
United States, CA, Temecula
Joined Nov 2001
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Great job painting!
Do you think your plane could be lighted up any? Did you shorten up the servo leads any? Did you build the plane stock?
Again, beautiful job
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Old Oct 22, 2003, 10:46 AM
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Palo Alto, California, United States
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ATA Flyer,

I built the plane stock except for:

1)Aileron cutouts and sheet aileron installation with music wire torque rods
2) 1/16" sheet horizontal tail
3) Minor reinforcing of the wing center section
4) removal of fuselage 'keel' material where wing attaches (allows aileron servo to fit better)
5) Cover with japanese tissue

I weighed the structure before installing any gear or covering and it was only 0.6 ounces. The model's gross weight is now 3.4 ounces, so I don't see any benefit in trying to lighten the balsa structure.

I used the stock servo leads and connectors on the Cirrus 5.4 servos.

If I had to build another one I would:
1) Move the batteries as far forward as possible, these planes need all the weight far forward to avoid a tail heavy condition. I have 0.25 ounce lead in the nose.
2) Improve the aileron linkage for more throw (mine is only 1/8")
3) Enlarge the vertical fin by 20% for less adverse yaw, or add a rudder servo.

I flew it again this morning after painting last night and it still flies fine. The nose weight helped tame the elevator response and it looks much better in the air painted.


Steve
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Old Oct 22, 2003, 10:49 AM
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Skunk Water, Rhode Island
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Glad it was a success, Steve
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Old Oct 22, 2003, 11:31 AM
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gainesville FL
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built this same model years ago when i was in high school but never got it to fly with stock rubber power....i gave up...think i might still have it in storage somewhere....hmmm.....gotta go look....working on a hellcat....not makinging much progress....great paintjob..i think it looks so much better with the great paintjob.

any chance you can get us some close ups of how the equipment is setup inside?...or how you made your ailerons?

would help me alot in my hellcat project.
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Old Oct 22, 2003, 11:41 AM
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New Boston, Texas, United States
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Steve,

Great looking model. I did not know that these little models would fly very well. I probably have all of the kits in this series. Thought that I would have to scale up the plans to get them to fly. Maybe now I will build them the stock size. What GWS motor did you use?

Jim
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Old Oct 22, 2003, 12:21 PM
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Guyaneze,

The photo shows all that can be seen through the cockpit. I mounted the equipment in the forward part of the fuselage, but should have moved the Li-Po batteries even farther forward to just behind the firewall.

The aileron linkage uses 1/32" MW torque rods that run through holes (slots, actually) in the wing ribs and the aileron is hinged with 1/8" wide pieces of Sig Easy Hinges (maybe too stiff, I'd like to find something less stiff). The aileron servo lies on its side and drives the torque rods using heat shrink tubing to form a flexible 'knee' between the torque rod arm and the servo pushrod. Some of this can be seen in the photo.

The elevator is 1/16" sheet and uses cut down Sig Easy Hinges. Another 1/32" music wire pushrod actuates the elevator.

Steve
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Old Oct 22, 2003, 12:24 PM
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Jim,

I don't have the exact motor number because I got the motor from one of the GWS 7.2 V dual-motor gear reduction drive units I had lying around the shop. I believe it is the same motor they offer in their Direct drive power system package, part # EDP-50X

Thanks,

Steve
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Old Oct 22, 2003, 01:42 PM
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Skunk Water, Rhode Island
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Steve, a good small airplane hinge is 20# test mono fishing line.
I chuck a cut-off T-pin, in the batt operated Dremel tool. Drill in the desired location, insert hinge, drop of thin Cy. Plug in to mating surface, another drop Cy. Leave a small gap for movement.

Steve
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Old Oct 22, 2003, 02:06 PM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
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Oh man- I've got that kit sitting in the bones- haven't touched it for a couple of years. I think I'm going to pull it out and finish it- this sounds like a great setup.

Thanks,

Sam
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Old Oct 22, 2003, 03:08 PM
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gainesville FL
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heehee..its amazing how many of us rc guys have these kits built or partially built.....like we all had the same idea....just never had the means or guts to actually try these planes with our rc equipment.

i was hoping the cirrus 3g servos would be out by now...but seems like thats not gonna happen any time soon
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Old Oct 22, 2003, 04:50 PM
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Jutst a point...did moving the CG forwards help with the adverse yaw?
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Old Oct 22, 2003, 05:18 PM
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Palo Alto, California, United States
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Not very much.

Moving the CG forward gives the rudder a small amount of extra weathervane stability, but the driving force behind the adverse yaw seems to be much greater than this. Aileron differential, larger rudder, or rudder/aileron mixing would all help the situation. Of course, it disappears if I just fly fast!


Steve
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