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Building Tips and technical articles. => ARF'S => Topic started by: Dave Nyce on November 15, 2007, 11:22:30 AM
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In other posts, it was recommended to replace the control systems in ARFs with non-metal ones. I have a Nobler ARF and a Flite Streak ARF, both from Top Flite. They each need some repair, so I'm planning to improve their controls.
I was wondering which control system or bellcrank would be suitable. Brodak sells a variety of bellcranks that are not metal. I suppose that it should be 3" or 4", but there many to choose from. For 4", for example, there is PSP (BB374), nylon (BB389), Nylon (BB396), strong arm 1/8" thick (BB391), strong arm 3/16" thick (BB392), heavy duty (BH396) and Sig (SH-480).
Also, on other websites, there are control systems including the bellcrank assembled with leadouts, but they are about $50.
So, which would be suitable for the ARF Nobler and Flite Streak? Thanks.
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Try www.controllinecentral.com - - Jim Snelson sells the Tom Morris Bellcrank, with leadouts attached, for around $9, depending on size, and excellent Morris Control Horns, too. All very reasonably priced.
Good luck,
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Thanks! The Tom Morris bellcranks look great. Do you know if the Nobler and Flite Streak should have the same size bellcranks as each other? And should they be 3", 3.5", or 4"? I'm hoping to learn the Old Time and Classic stunt pattens. Thanks again!
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David,
Each of those models were built with 3 inch bellcranks and this size will be fine until you become more proficient. It's true that the 4 inch bellcrank is more popular (it gives a smoother control feel for most of us), but many models were built and flown over the years with a 3 inch bellcrank.
It's been some time since I replaced the controls in my NoblARF, but IIRC there wasn't much room in there for anything bigger than a 3 incher anyway.
One point to consider: The Tom Morris bellcranks are the Cadillacs of our event, but they are of the "suspended" design. That is, they are designed for a central pivot rod to be supported top and bottom with plywood pads. The bellcrank will ride in between supported top and bottom with steel or brass collars. This type of bellcrank will give a smooth control feel, but will require more mods to the Nobler. It's silly to use something this sophisticated in the Flight Streak.
IMHO, get some regular bolt-through Brodak or SIG 3" nylon bellcranks, Install your leadouts with brass tubing for bushings and simply bolt them back in the original location.
I've attached a couple of pictures to better explain my post. The first shows the suspended Morris bellcrank and the second shows the Brodak nylon bellcrank with the new bushed leadouts in an ARC Cardinal.
My .02,
Ron
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Thanks a lot for your help!
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The Flite Streak is just fine as delivered....put the pushrod to the furthest hole from the control surface....
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According to some previous posts, the Nobler ARF controls should be replaced to avoid failure. I assumed that was because the leadout cables were probably connected directly with the metal bellcrank (I assembled mine a few years ago, and had forgotten what the control system looked like). I took my Top Flite Nobler ARF wing off, and the photo below shows the leadout connection to the bellcrank. With that connecting pivot, it seems like the controls should be reliable, although maybe not as smooth as the more recommended types. It looks like there should be no problem of the cable being abraded by the metal bellcrank, or vice versa. Am I missing something?
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The problems also lie in the crimped nature of the connections. Even though many have used crimping as a form of terminating lines, swaging is much more reliable. Plus, I am not REAL sure just how much care is taken by the Chinese in their "crimping". Many, many people reported failures with the crimped leadouts. Some in just 6 flights or less, others have a couple dozen or so. Since it is apart, the extra security would seem a no brainer.
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Thanks Bill. I am waiting to receive some bellcranks that I have on order. I also corrected the alignment of the tail on my Flite Streak. So, I should have them both ready soon (Nobler and Flite Streak). Then, I hope to meet up with you again for some more help to learn the stunt patterns.
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Thanks Bill. I am waiting to receive some bellcranks that I have on order. I also corrected the alignment of the tail on my Flite Streak. So, I should have them both ready soon (Nobler and Flite Streak). Then, I hope to meet up with you again for some more help to learn the stunt patterns.
I am looking forward to getting back together with you, too. We just need to get a good plan of action going to have you ready for contest season next year! ;D
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Thanks, Tom, for the Nobler photos.
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Thanks Ty. But I'm planning to just replace the Flite Streak bellcrank and lines through the access cover, and not to disassemble it. I have disassembled the Nobler, and will also switch out that bellcrank and control lines.