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Going CL with tis R/C model

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Going CL with tis R/C model

Old 06-19-2010, 09:37 AM
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Avaiojet
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Default Going CL with tis R/C model

My mind and my pocket book cannot deal with R/C any longer. Well, for the time being anyway.

So, I decided to convert this, already modified, Adrian Paige R/C model to CL. Not a great photo.

Anyone do CL to a Paige Gee Bee Z?

This model is 55" in span and I currently have a vintage OS .80 under the bonnet.

I'm thinking of pumping it up a bit. A good 60, or possibly a Webra 120, on 70' lines?

Charles
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Old 06-19-2010, 02:27 PM
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dennis
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Default RE: Going CL with tis R/C model

Your biggest problem will be retrofitting that model for C/l.
Large C/L scale models have quite a lot of pull on the handle and usually R/C models dont have the right structure to hold the bellcrank and the fuselage in harmony.
So if you can't get some new structure into the fuselage to take the pull of the model flying I'm afraid it's maiden flight may be brief and perhaps hazardous.. This is the major problem but there are others also.
Dennis
Old 06-19-2010, 02:43 PM
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Avaiojet
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Default RE: Going CL with tis R/C model

Dennis,

Thanks for that info. Something to think about.

I believe I have plenty of room in the fuselage to epoxy a mount that goes from side to side.

I could take a photo of the wing cradle and Post it. Certainly don't want to loose this airplane, I spent plenty of time making changes to arrive at a reasonably scale model.

Should balance at the same CG as the R/C model?

Charles
Old 06-19-2010, 03:45 PM
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da Rock
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Default RE: Going CL with tis R/C model

The bellcrank mount really needs to connect with at least one substantial structure. Fuselage walls aren't enough. Connecting to a bulkhead is a good idea.

The CG works for flight, any kind, even tethered flight. It's a pitch stability deal and how the surfaces are driven doesn't change that and the leadouts don't influence pitch stability.

If your old engine runs reliably, you really don't need more. And you certainly don't want more weight.
Old 06-19-2010, 05:11 PM
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Jim Thomerson
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Default RE: Going CL with tis R/C model

I'd start out with the CG at about 15%. At 25% you may have a really twitchy airplane.
Old 06-19-2010, 08:47 PM
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Default RE: Going CL with tis R/C model

Hi interesting subject for the conversion. I love the Idea and have done two conversions in the past. Jim is dead on with the recomendation of 15% MAC for the CG. If you try to use the quarter chord or even more aft that may be used in the RC application I think you will find the airplane very difficult on the lines.

Perhaps there is one more item you should pay attention to, That is the belcranks vertical orientation in that massive and deep fuselage. If you mount it low in the fuselage and route the leadouts through the wing the fuse may want to hang flat on the outside and look somewhat strange.

My preferance would be to mount the bellcrank vertically up more in the center of the mass and direct the leadouts out the side and routed through a simple wire leadout standoff out near the wingtip.

The for and aft orientation of the bellcrank should be near the CG as da rock indicated (15%) but the lines at the tip guide I would set the guide so that the lines angle aft slightly around 2 degrees. In other words not ninety degrees out the side from the bellbcrank but just aft a bit or a few degrees less than ninety. This would apply with either a single or a dual outlet guide.

John

Looking forward to your maiden, cool project.
Old 06-20-2010, 07:29 AM
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R8893
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Default RE: Going CL with tis R/C model

Charles, are you planning to include throttle control? Photo of converted Skyshark Val. Have also done Brian Taylor Typhoon, Royal FW-190, and Hobby Hanger(?) Typhoon.
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Old 06-20-2010, 11:14 AM
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Default RE: Going CL with tis R/C model

I would try to incorporate an adjustable lead out at the wing tip as this can be used to adjust line tension. Regardless of whether it is CL or RC, the CG relates to the airfoil being used. An airplane needs to be balanced properly to fly right. Get the CG at the thickest part of the airfoil.
This should not be a difficult conversion. You just have to mount the bellcrank properly, even if this means adding new structure inside the fuse.
Of course it would be best to have it mounted in the wings between rib bays near the spar. It may require some major surgery to do this though. Especially if you have to make holes in all of the wing ribs to run the lines out to the tip.
Old 06-20-2010, 03:51 PM
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Jim Thomerson
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Default RE: Going CL with tis R/C model

I've been flying CL since 1953, competitively since 1955. Consider that when you get conflicting advice.
Old 06-20-2010, 05:24 PM
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da Rock
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Default RE: Going CL with tis R/C model


ORIGINAL: Jim Thomerson

I've been flying CL since 1953, competitively since 1955. Consider that when you get conflicting advice.

Why you've been around almost forever.

Our ranks are thinning out, just like our hair.

You know, noone has offered any conflicting advice?
Old 06-21-2010, 10:37 AM
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Jim Thomerson
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Default RE: Going CL with tis R/C model

I understood some conflicting advice on CG position.
Old 06-21-2010, 05:50 PM
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clscale-RCU
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Default RE: Going CL with tis R/C model

I have converted lots of RC models to CL scale, using these general rules all of them have flown great...I even converted the 1/4 scale Bravo kit from Sig.

I have seen a Gee Bee fly CL before, it can work.

Here is what I would do.

1) they are right, attach the bellcrank to solid structure that can take up to 50 lbs of pull.
2) put an adjustable line guide on the model, the position of the line guiide relative to the CG determines the line tension. The Bellcrank can be almost anywhere. I generally put the bolt for the Bellcrank 1" behind the CG
3) 1 or 2 ounces of right wingtip weight would help, but I have flown some models without right wing tip weight.
4) make the tailwheel adjustable, but fixed, the position of the tailwheel is critical to getting a good taxi
5) I would highly recommend throttle control for the model, a model that big would be scary if the engine was stuck at full power with no throttle. I have a PDF copy of my book that talks about the electronics used to control the throttle. Or you can install a 3-line system which will cost alsmot as much as the single channel system that I use.
6) I would start with the CG at 25% and go from there.

When you fly it, hold full up elevator and throttle up slowly, nose may pitch over if you throttle up too quickly....it would look great.

check out this web site, there some large CL scale models on this web site that can show what is possible....you can get a copy of my CL scale book (PDF copy) from this web site.

http://www.eicnetwork.com/eic/Home/Home.html

Land softly
Old 06-22-2010, 05:57 AM
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Avaiojet
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Default RE: Going CL with tis R/C model

Guys,

Thanks for the replies and info. I've been really busy with a new full time job, but I will respond to all replys and info at my first chance.

>
I never heard of this? I thought "line tension" was what it is. How can line tension be changed? Inertia is inertia. One would think?

Wing is bolt on also, this shouldn't matter? I'll get a photo or two of the fuselage inside and better photos of the model's construction.

Thanks,

Charles



Old 06-22-2010, 07:13 AM
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Default RE: Going CL with tis R/C model

Charles an adjustable outlet slider is just a means of angling the lines aft out near the wingtip and making it adjustable for different wind conditions. In other words as I indicated earlier the lines will not come straight out the side of the airplane ninety degrees to the fuselage but angle aft a bit.

If you hold the handle and have someone pick up the airplane then put tension on it you can see the airplane does slightly point to the outside of the circle and this is one of the factors that keeps the lines tight. The act of sliding the outlet guides at the wingtip aft will increase line tension in flight.

John
Old 06-22-2010, 07:18 AM
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da Rock
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Default RE: Going CL with tis R/C model

The line tension is what it is, but it's affected some by the angle the airplane is yawed and it affects that angle too. Adjustable guides can be moved to that angle. More to the point, fixed guides can pull the model toward an inefficient angle. With adjustable guides, you can easily trim the yaw, or at least the affect of the yaw.

In the really old days, guys very often cut the fixed leadouts and moved them when the plane flew crappy because they'd guessed wrong and placed the leadouts badly. Sort of labor-intensive adjustables
Old 06-22-2010, 12:49 PM
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Default RE: Going CL with tis R/C model

line sliders are great to have when you can move'em aft for a windy day and move'em forward for those pristine calm days.


John
Old 06-22-2010, 04:44 PM
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clscale-RCU
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Default RE: Going CL with tis R/C model

A removable wing is not common in CL but there is no problem having a removable wing. My 80" span camera plane and 80" cub all have removable wings, I couldn't haul them to the flying field without removing the wiings.

I even have a old RC trainer that I converted to CL with an OS-35 to teach some kids how to fly, the wing rubber bands on the fuselage and it flies great. I got the airplane and motor at an auction for $25, couldn't pass it up.



Have fun!
Old 06-22-2010, 08:03 PM
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Jim Thomerson
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Default RE: Going CL with tis R/C model

I'm not sure you need an adjustable leadout guide. I am all for them on stunt airplanes, so one can deal with problems of low line tension up high. I presume you will be flying mostly straight and level. I think if you put the line guide where the airplane angles out a couple/three degrees when suspended from the leadout guide, it will be fine. One of the virtues of adjustable things is that you can move them around and see what effect it has on how the airplane flies, so I am generally for them. Fred says 25% CG is OK. I am doubtful, but then I have never flown a scale CL airplane.
Old 06-23-2010, 06:42 PM
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Avaiojet
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Default RE: Going CL with tis R/C model

Here are a few more photos of my R/C Gee Bee Z, soon to be a CL Gee Bee Z.

I have a red "three line" handle which I will use. If I can find it? I truly don't have the mindset for electric anything anymore. In fact, I'm selling everything I have that's R/C.

Many "fake" ribs in the wing, and fortunately the wing has little dihedral and the fuselage, as fat as it it is, offers plenty of room for the three line belcrank "gismo" needed for throttle control. I have to find one. Anyone got one?

The fuse side doublers are 1/32 plywood attached to balsa. I am a builder, obviously, as can be seen by the many changes I made to a fine semi-scale kit by Piage Aviation. Scale outlines now! Or close anyway.

Take a look!
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Old 06-24-2010, 04:42 PM
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Default RE: Going CL with tis R/C model

The adjustable line guide is to set the line tension so larger models don't pull your arm off. When I converted the 1/4 scale Bravo a slight change in the line guide made a huge difference the line tension, from 50 plus lbs to something more reasonable. The adjustable line guide for scale has a totaly different purpose than stunt. For the smaller models it's not really needed, but when you get into the 8 lbs or heavier category the line tension can become large and the adjustable line guide lets to set so that you can fly with one hand.

As for the CG location, scale models trim out the models differently than CL stunt. If the CG is at the 25% mark (avg chord) then you get a very stable model for scale stuff, flies like a dog compared to a stunt model, but I am not tryinig to do the stunt pattern with my scale models.

If you have any older JR radios and recivers with DSC (look on the back of the transmitter) give me a call those are a plug and play for CL scale electronics.

for the 3-line handle make sure you get the matching bellcrank and remember the third line must be an exact length to work properly. Also there can't be any friction in the throttle system to have it work smoothly, My 3-line hardware is in my drawer haven't used it in over 15 years since I converted to electronic controls.

here is the web site for the PDF copy of my book

http://www.eicnetwork.com/eic/Scale.html

land softly!
Old 06-24-2010, 06:45 PM
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Avaiojet
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Default RE: Going CL with tis R/C model

Fred,

Thanks for those notes. That stuff in your clothing draw that you have no use for, 15 years proves it, just bag n gag the items and send them to me.

PM me for my address. OK? OK!

I understand now how line tension can be adjusted AND the benifits of it. The "pull" could out last the strength of the flyer.

That would be an interesting sight.

Seeing my lines won't exit the wing tip OR be in the wing, for that matter, I'll have to give my adjustment gismo some thought.

Exit "ring" attached to a wire, with the benifit of sliding forward and backward on the wire.

That could work. Has to be neat in looks.

Charles
Old 06-24-2010, 08:59 PM
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Jim Thomerson
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Default RE: Going CL with tis R/C model

I'm interested to see how you do the adjustable leadouts. I've done a couple with leadouts above the wing, but did not think them all that pretty. Mine were made out of wood, and I think wire would look better.
Old 06-24-2010, 09:49 PM
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Default RE: Going CL with tis R/C model

Jim,

I'm thinking a tube in a tube.

One tube, the inner one that sits from LE to TE could be about three inches long and made of aluminum. Designed to be removed, just for looks when not in use. Could fasten to hard spots built into the wing. Simple hollow supports can control the distance this tube sits from the wing. A tad longer support, near the trailing edge or rib taper, would allow the inner tube to sit level and provide height adjustments. Ie., just change the length of the supports.

A "snug fit" or "slider" tube, possibly .675" long, with a ring welded on top, for lines obviously, would do nicly. Holes drilled and spaced for adjustment fore and aft on both the "slider" and the inner tube. Clevis could do the trick or it could be bolted in place. Choose the whole necessary.

I believe I've described this gismo quite well.

If you want to pritty it up a bit, tapered heads/ends, like bullets, can be filed on the inner tube front and rear.

I believe a .25" solid inner tube would be fine. Possibly .375" thick max. for this size and weight model.

Wingspan is only 55"

This gismo could work. Could use a name.

Charles





Old 06-25-2010, 07:46 AM
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R8893
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Default RE: Going CL with tis R/C model

Easily made adjustable leadout guide. Brass tubing guides are actually lined with yellow Sullivan nyrod to avoid scratching insulation off coated lines used with electronic controls.
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Old 06-25-2010, 08:11 AM
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Jim Thomerson
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Default RE: Going CL with tis R/C model

My wooden ones are similar idea, but built integral to wingtip. I also use the yellow nyrod tubes, just glued into the plywood slider.

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