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Author Topic: Question for Randy Powel on the RMD  (Read 865 times)

Offline Allan Perret

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Question for Randy Powel on the RMD
« on: July 06, 2011, 01:20:48 PM »
On the Ringmaster Delux.   When I got into the flight trimming, the biggest issue was turning tighter insides than outsides. So I drooped the elevator, and then drooped it 2 more times till it was 6~8° down with flaps level.  Somewhat better but still tighter insides.  It looked so odd I went back to neutral elevator and decided to live with and get used to the tighter insides.  Then one day after playing around with pipe adjustments, I decided to pull the pipe and make a couple of flights on muffler just for a reference.  Guess what, now inside / outside turn rates are nearly the same.  So I'm thinking the pipe hanging under the wing was blocking or disturbing the airflow which made the down elevator less effective than up elevator, so much so that the normal drooping which should have corrected it, did not in this case.  Was wondering if you experienced this with either of you two RMD's ?   I have been flying without the pipe since discovering this, because that AT-36 has plenty enough guts for this plane on the muffler.  
« Last Edit: July 06, 2011, 04:34:35 PM by Allan Perret »
Allan Perret
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Slidell, Louisiana

Offline Randy Powell

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Re: Question for Randy Powel on the RMD
« Reply #1 on: July 06, 2011, 09:28:39 PM »
Allan,

Nope, no issue. The plane (the new one) initially turned better outside than inside, but that was mostly because I had pre-adjusted a bit of down elevator in. Turned out I didn't need it and re-zeroed the elevator to the flaps and it was fine. The first Ring was pretty noseheavy and didn't want to turn either way initially. but adding tail weight fixed that. It's why the new one had an inch shorter nose.

So, at least from my experience, the pipe slung below the wing doesn't make any difference. I suspect that you either have a flexible control system (unlikely - I saw the one you built) or the tail is flexing unevenly due to the pipe.
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 Randy Powell

Offline Allan Perret

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Re: Question for Randy Powel on the RMD
« Reply #2 on: July 07, 2011, 04:02:47 AM »
I used cf pushrods, and the elevator rod is in tension for down input.

The elevator is not sheeted, but does not seem to have excessive flex.
Allan Perret
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Slidell, Louisiana

Offline Randy Powell

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Re: Question for Randy Powel on the RMD
« Reply #3 on: July 08, 2011, 03:42:50 PM »
Allan,

Hnmm, I probably would have kept working the control ratios, but if you've got it working with the muffler, cool. As noted, I don't have the problem. I do have other problems, but they have mostly been related to power train (and I think I may finally have them sorted out).

Where is the balance point? I have mine fairly fair back (about 28%).
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 Randy Powell


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