Oriental trim solution -- Thanks, Bob!

Recently, at the end of Mike Haverly's thread about his new Oriental, I mentioned the ongoing trim problems I have had with my now 2-year-old Oriental. I said I'd tried everything to fix the problem (it won't turn insides) to no avail. But I added that somebody probably would come along with a simple solution that I hadn't tried.
Sure enough, Bob Reeves made a suggestion so obvious I should have tried it first. I think he's hit upon the answer.
What I had tried to date included a number of things I suspected intuitively would not help much, but anything was worth a try since the plane is so hard to fly well as is. Among the things that may have helped a little but not enough to make much difference were:
-- Sealed hinge and elevator lines (I'm sure this helped the plane's performance overall but not the specific problem of turning insides).
-- Adjusted engine thrust line (not much help).
-- Biased handle (no help).
-- Cut in and added up elevator travel (no help).
Bob's suggestion was the one thing I had not thought of -- to check for pushrod flex. Out of sight, out of mind, I guess.
A quick check in the workshop reveals evidence of significant pushrod flex. I can hold the elevator straight and pull on the up line, and the flap moves. Clearly the rod is flexing.
Can't believe I didn't deal with this when I built it, certainly a wire pushrod needs a guide over that distance, or switch to an arrow shaft.
I'll have to cut in again and install some sort of a pushrod guide. I'm betting this will make the plane turn insides as well as outsides.
I'll report if this actually does the trick.
Thanks to you, Bob, for the help!
--jt

Sometimes it is the simple things!!!

I never use only wire pushrods anymore, they are all carbon fibre rods Nil flex....avoids problems later.

OK, I lied, I use wire in 15 -20sized planes........but not in anything bigger.

Hope it sorts out the problem for you.

Will look for you post on the result.

John,

Don't feel like the Lone Ranger on your goof. Seems like us old modelers are forgetting more than we learned. I did the same thing on the Stuka. Bob Whitely showed me as follows. Stabalize the flaps in the full down position with one hand then push down on the elevators with the other hand. I was amazed how little (air pressure, finger pressure) was required to neutralize the elevators to zero!!!!! Not very effective on inside loops. The fix. added a 1/16th rod parallel to the existing pushrod with 1/16th and 1/8 plywood spacers creating a beam in the plane of bending on the rod. Solved the problem and it is/was quite rigid. As you know, the Stuka is now history but Stuka two is in the mail.

Bob Smiley

Bob,
I didn't know the Stuka was history. Sorry, that was a nice ship.
Chris...

John, you are welcome, lucky guess and glad to have helped.

Interesting thing about wire pushrods, the straighter the push rod is the less chance it will flex. If you have a bend at one or both ends it will flex rather easily. The 3/32 push rod in my ARF Nobler is not supported or beefed up in any way, it works fine but it is a straight shot from control horn to control horn..

John,

In trying to repay the many favors from Don McClave, I once mailed to him some cut-offs I had laying around, these being from those nearly-magic aluminum foil, CF, aluminum foil F1A tailbooms I bought in Russia. As long as I was sending stuff, tossed in a big ball of Kevlar tow.

Next time Don and I spoke he said the package got to his home at the prefect time as he was just then finishing flap-to-elevator pushrod installation on his Oriental, this being a 3/32" piece of piano wire.

Don selected a chunk of the right length, CA'd it directly to pushrod, wrapped it all with Kevlar.

To this day I think it quite funny, not to mention butt-ugly, but you might consider something like this as you probably don't want to break ends of pushrod free.

I've got more F1A booms, even have some scrap CF rods bought by the handfull at Puyallup show. Either will work, let me know what you need.

Incidentally, I sullied your reputation, along with that of Mike's, in post N.45 to Brett's "OK, this is how to do it - 20FP" thread which has lead such a storied life. Sorry, but I just had to do it...

Got my NW Regionals package a couple days ago. As always, thanks for all the work you do on my behalf.

(Hey, you're a highly-paid copy editor. Should it be "on my behalf" or "in my behalf?")

As expected, getting rid of the pushrod flex definitely got the Oriental flying much better. I flew it today and found the inside turning much improved.
Last year I dropped out of Classic a couple of times because the Oriental was so hard to fly that I couldn't make a smooth transition to the PA plane. If PA came after classic, I needed practice flights to adjust, so if time pressure prevented it, I'd quit classic. (At contests I'm always doing more than one thing, either officiating or competing, so practice flights are sometimes a luxury).
This morning I was able to fly the Oriental a couple of times and switch to the Lite Wave, no problem. So I may enter classic a bit more this year.
The pushrod fix was pretty easy. I cut in through the bottom of the fuselage and simply built a hardwood guide around the rod where it passes through a bulkhead.
Many thanks again to Bob Reeves and everyone else who offered ideas.
And, Dan, "in" or "on" -- either one is fine!
--jt

engineering solution in search of a problem. Carbon fiber pushrods and titanium rod ends. It is amazing how much force you can transmit with just a 1/16 in. pushrod, if it has a few guides on it. Keep the guides within 6 in. or so of each other and there is virutally zero flex. Add a 4/40 locking clevis or Rocket City ball end and you've got a great pushrod.

Mr. Rutherford wrote:

"John,

In trying to repay the many favors from Don McClave, I once mailed to him some cut-offs I had laying around, these being from those nearly-magic aluminum foil, CF, aluminum foil F1A tailbooms I bought in Russia. As long as I was sending stuff, tossed in a big ball of Kevlar tow....

Dan"

Mr. R,

I thought that I knew about most of the currently used model building materials. I am, however, unfamiliar with Kevlar® tow. Is this some new, highly secret, high zoot building material? If so, what is (are) its application(s)?

Thank you for any information you are able to provide.

(NSF, TIC)

OS

OS,

Kevlar tow is the floor sweepings from the shop where Sullivan made the "Tufstrand" kevlar lines ( kidding!!).

But that is basically what it is,an unfinished form of Kevlar material, not woven into cloth or spun into threads.

Mr. R,

I thought that I knew about most of the currently used model building materials. I am, however, unfamiliar with Kevlar® tow. Is this some new, highly secret, high zoot building material? If so, what is (are) its application(s)?

Thank you for any information you are able to provide.

(NSF, TIC)

OS

The Old Sourdough
Ruksakinmakiak, Alaska, US of A

Dear O.S.,

My most sincere apologies. I sometimes forget your unfortunate ancestral background, the area in which you live, your aversion to anything modern. Such as a flush toilet, one actually located in the house...

Thus, for purposes of this discussion, "Kevlar tow" may effectively be translated to: Yellow string which is hard to cut.

Reference my earlier post for one application of yellow string which is hard to cut.

Coming to see us in 2004? Let me know, I'll give you a big wad of yellow string which is hard to cut. I once bought a 25-pound spool of the stuff at Boeing Surplus, am having a great deal of trouble getting it all used up.

To the point where I am thinking of flushing it down a toilet. We have a couple handily sited right in our house, even if the very idea of such convenience must make it hard for you to sleep at night.