Almost forgot. Check the pressure in the nose tire. This has been known to have an effect. I think the general consensus is that about 17PSI is where you need to be. YMMV so try it at differing pressures.
----- Original Message ----- From: Harry L. Francis To: David Winters Cc: [email protected] Sent: Thursday, January 08, 2009 10:57 AM Subject: RE: [ercoupe-tech] LOOKING FOR ADVICE re venturi Dave, on shimmy. This is most often caused by one of three things: Most likely the sissors linkage being loose. 1,Out of balance nose wheel rremove and balance 2 loose linkage on the sissors. the bolts holding the sissores to the nose assy must be properly tightened. the sissors should have a serrated washer (2) between the sissors and the mount. The washer locks the sissors against the bushing that is inside the mount, making the bushing move as the sissors opens and closes, and does not let the sissors move against the bolt. Often I have seen mechanics think the sissors must be loose enough to move, and they leave the bolt loose to allow this. The bolt wears the hole in the sissors, allowing shimmy. Fred designed the system so the bolt against the sissors, locks the sissors to the bushing by the serrated washer, using the bushing as wearing/replaceable part, preventing loosness on the sissors, and preventing shimmy. see Ercoupe Parts book, page 20/21a, fig 12/12a, items 34, 50, 43, etc... 3. Loose bearings in the wheel. If you have a single fork system, the wheel has a single bearing, that is a special pre-loaded bearing, with no play. Replacing it with a similar numbered bearing ( but not special preloaded type) results in play in the wheel to bearing , and results in shimmy. Replace bearing with proper pre-loaded bearing...See page # 40 Ercoupe Service Manual, para4, last sentence. "This deep groove preloaded......" Hope the above helps... Fly Safe - Have Fun Harry Francis --- On Thu, 1/8/09, David Winters <[email protected]> wrote: From: David Winters <[email protected]> Subject: RE: [ercoupe-tech] LOOKING FOR ADVICE re venturi To: "'John Cooper'" <[email protected]>, [email protected] Date: Thursday, January 8, 2009, 10:53 AM Shucks, Back to the shop she goes. The DG is OOC. So I said to remove it. BUT, the A&P is afraid to remove the DG and leave only the Attitude Indicator on the venturi. I have a BIG (4 inch) venturi, and he thinks it will overpower, over-spin, and destroy the solitary attitude indicator. I LIKE having the attitude indicator, so I do not care to remove it. Is he correct? (He admits he is only guessing.) Anybody have a smaller venture for sale? (I have no idea how much trouble it is to install one.) The bird had her nose gear all reconditioned, but still shimmies on landing roll-out like a fresh burlesque queen. Any theories as to what to do to fix it are welcome. Dave W
