jetdriven Posted February 15, 2021 Report Share Posted February 15, 2021 This is the J model but after 500 hours it’s still exactly right.... You just got to shim it once. 1 Quote Link to comment Share on other sites More sharing options...
PT20J Posted February 15, 2021 Report Share Posted February 15, 2021 8 minutes ago, jetdriven said: This is the J model but after 500 hours it’s still exactly right.... You just got to shim it once. After you fix the cowling so it doesn’t shift up with air pressure. Quote Link to comment Share on other sites More sharing options...
carusoam Posted February 15, 2021 Report Share Posted February 15, 2021 Congrats on your first posts, Andrew! Let’s take a moment to assess what you have... Do you have a hartzell TopProp? If you have 310hp powering your plane, you probably have the TopProp... Do you have a 1/4” step between your spinner and cowling? Are you expecting a nice smooth transition like what Byron / JetDriven is showing in his pic above? You have properly replaced the lord donuts on the engine mount... there are three of one type of donut, and a fourth one with a different part number... (something to check) If you have all this... Good news / bad news... 1) It is (technically) normal... 2) Hartzell spinners don’t match Ovation cowling and are off by about 1/2” diameter (too small)... 3) Somewhere along the way... Hartzell was going to supply a proper diameter for us... it’s been eight years since I looked into it... PP thoughts only, not a mechanic... Best regards, -a- Byron’s pic, rotated... Quote Link to comment Share on other sites More sharing options...
carusoam Posted February 15, 2021 Report Share Posted February 15, 2021 Russ / Cruiser shared a pic of his TopProp above.... With its diminutive spinner... -a- Quote Link to comment Share on other sites More sharing options...
jetdriven Posted February 15, 2021 Report Share Posted February 15, 2021 2 hours ago, PT20J said: After you fix the cowling so it doesn’t shift up with air pressure. Do the Ovations do this? Quote Link to comment Share on other sites More sharing options...
PT20J Posted February 15, 2021 Report Share Posted February 15, 2021 1 hour ago, jetdriven said: Do the Ovations do this? Dunno, just know that my '94 J does. Interesting that my '78 J didn't noticeably. Quote Link to comment Share on other sites More sharing options...
MIm20c Posted February 16, 2021 Report Share Posted February 16, 2021 Laser has the proper shims and the fit is perfect after install. Quote Link to comment Share on other sites More sharing options...
aramkis Posted February 16, 2021 Report Share Posted February 16, 2021 7 hours ago, carusoam said: Let’s take a moment to assess what you have... Do you have a hartzell TopProp? If you have 310hp powering your plane, you probably have the TopProp... Do you have a 1/4” step between your spinner and cowling? Are you expecting a nice smooth transition like what Byron / JetDriven is showing in his pic above? You have properly replaced the lord donuts on the engine mount... there are three of one type of donut, and a fourth one with a different part number... (something to check) If you have all this... Good news / bad news... 1) It is (technically) normal... 2) Hartzell spinners don’t match Ovation cowling and are off by about 1/2” diameter (too small)... 3) Somewhere along the way... Hartzell was going to supply a proper diameter for us... it’s been eight years since I looked into it... PP thoughts only, not a mechanic... Hello Carusoam, You pretty much hit the nail on the head - I do have the 310HP conversion and therefore, I have Hartzell’s Top Prop. Unfortunately, I have much more than a 1/4" gap at the top of the spinner - I would say it is between 3/4" to 1" difference. I will take a photo and post it as soon as possible, but in lieu of that picture, my config looks very much like the photo taken by the OP, Txbyker, of his airplane. If I had just the 1/4" above and below, I would be delighted - heck, if I had 1/2" on top and another 1/2" on the bottom, then I would also be pleased. But having about an inch above and about -.25" below is unacceptable. My IA replaced all four donuts recently and I recall him mentioning that three of them were the same part and the fourth was slightly different, so I am confident that he installed the correct mounts. There is pretty much no wiggle in the engine or the cowling, this disparity in the centering of the prop/spinner to the cowling is most certainly a manufacturing flaw that should be adjustable by shims per service bulletin from the factory. I plan to reach out to them to determine if this is a topic the new management is willing to address as one of their action items. I will be sure to post any learnings and information gleaned from the factory reps to this post. Andrew 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted February 16, 2021 Report Share Posted February 16, 2021 Andrew, You might want to post a few pics of that if you have them... different angles... HD if available... I saw the doc around here earlier... He knows IO550s in several varieties... He may have some insight to share... @M20Doc (question about shimming an IO550 in an M20R, 1” sag kind of challenge) PP thoughts only, Not a mechanic... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
PT20J Posted February 16, 2021 Report Share Posted February 16, 2021 9 minutes ago, MIm20c said: Laser has the proper shims and the fit is perfect after install. Not sure if you are talking about the engine shims or the cowling mod LASAR used to sell. I have heard that LASAR used to have a mod for the J cowling that involved installing nut plates where the bottom cowling attaches ahead of the nose gear. However, when I contacted them I was told that the mod they used to do in the shop was to change the floating camloc receptacles to non-floating. But mine already has those. I think Byron modified his cowling to fix it, but he is way more skilled at fiberglass than I am. Skip Quote Link to comment Share on other sites More sharing options...
EricJ Posted February 16, 2021 Report Share Posted February 16, 2021 5 hours ago, PT20J said: Dunno, just know that my '94 J does. Interesting that my '78 J didn't noticeably. My 77J does it. It'll be perfect when I put the cowl on, and as soon as it gets flown it's adjusted itself up. It does this most of the time. 1 Quote Link to comment Share on other sites More sharing options...
V1VRV2 Posted February 16, 2021 Report Share Posted February 16, 2021 Pilots are an unaccepting bunch of perfectionists. The Ovation spinner does not line up with the top of the cowl. That’s how it is. Verified by Brian Kendrick in January when I inquired. Learn to live with it. I have! Sort of! Maybe one day! 1 Quote Link to comment Share on other sites More sharing options...
ArtVandelay Posted February 16, 2021 Report Share Posted February 16, 2021 Dunno, just know that my '94 J does. Interesting that my '78 J didn't noticeably.My 78 does, I told the mechanic this, that with new engine mounts there would be significant sag, and told him to plan accordingly.He didn’t listen, now it’s not perfect and he can’t adjust it any further.Tom Quote Link to comment Share on other sites More sharing options...
201Steve Posted February 18, 2021 Report Share Posted February 18, 2021 (edited) I don’t think the AP question has been answered; I believe the AP of choice down there is Phil Jiminez. Or so I recall reading. Edited February 19, 2021 by 201Steve Quote Link to comment Share on other sites More sharing options...
MIm20c Posted February 19, 2021 Report Share Posted February 19, 2021 34 minutes ago, 201Steve said: I don’t think this question has been answered; I believe the AP of choice down there is Phil Jiminez. Or so I recall reading. A large number of ovations have the sag. Has nothing to do with DH or the lord mount condition (within reason). The sag of the engine does not change in flight. @aramkis needs to call Lasar and ask for two shims (one for each front engine mount). Find a willing A&P, don’t bother with the ones that are also unwilling to raise FF to maintain healthy cylinders, and toss them in. Quote Link to comment Share on other sites More sharing options...
V1VRV2 Posted February 19, 2021 Report Share Posted February 19, 2021 So is the problem aesthetic or an engine alignment issue? No one has pointed out anything that says there is something incorrect about the alignment. Hoping for some clarification. Quote Link to comment Share on other sites More sharing options...
201Steve Posted February 19, 2021 Report Share Posted February 19, 2021 1 hour ago, MIm20c said: A large number of ovations have the sag. Has nothing to do with DH or the lord mount condition (within reason). The sag of the engine does not change in flight. @aramkis needs to call Lasar and ask for two shims (one for each front engine mount). Find a willing A&P, don’t bother with the ones that are also unwilling to raise FF to maintain healthy cylinders, and toss them in. No no, not the question of whether the sag is right or wrong. I have no clue. He asked about a good AP in Southeast FL. Quote Link to comment Share on other sites More sharing options...
aramkis Posted February 19, 2021 Report Share Posted February 19, 2021 All, I appreciate everyone's comments and contributions to this thread. I plan to visit the airplane this weekend and will take some pictures to share on this forum. My main query about the sag is not just about whether it is right or wrong, good or bad, negligible or should be addressed. Considering that I have flown this airplane for almost 200 hours over the last two years that I have owned it, I do not believe that it is a safety issue. The bottom of the spinner has plenty clearance from the front of the cowling. My main concern is whether the sag is costing me performance since the top of the spinner does not align with the top of the cowling, and therefore, there is a sizable amount of exposed surface area that is directly perpendicular to the airflow. Secondly, and to be quite honest, much of this is about aesthetics - the Mooney Ovation is a gorgeously streamlined airplane, so to have this disjointed look up front where it should be at it most streamlined, is somewhat disconcerting and bothersome to me. One question that has surfaced is whether there is a concern amongst those who have shimmed the engine that because this is not a factory endorsed repair, it would provide an insurance company with an opportunity to deny any claim, if, god forbid, the unthinkable happened that required a claim, even if there is no connection between the incident and the engine mount. We all know that insurance companies will do and find whatever possible to avoid paying out. Andrew Quote Link to comment Share on other sites More sharing options...
Niko182 Posted February 20, 2021 Report Share Posted February 20, 2021 What about getting a field approval to shim the engine? Quote Link to comment Share on other sites More sharing options...
bfreelove Posted February 20, 2021 Report Share Posted February 20, 2021 I wouldn't worry about it costing any performance. In fact the exposed cowling on top of the spinner may even help performance a tiny bit. Some engineers will oversize the spinner "afterbody" section of the cowling. This is sometimes called a "boundary layer compressor". Basically the boundary layer at the aft portion of the spinner is pretty beat up from the combination of the spinner rotation, and the shank section of the propellor. Having an abrupt change in the cross section at the cowling interface, forces the boundary layer to speed upto make it over the bump (it gives it some gradient to move towards) and can help it attach to the cowling a lot better. There is of course a specified height and radius for this so chances are what you have wouldn't be perfect, but the effect would be hard to measure either way. The Ovation spinners are fairly small and the shank portion of the propeller is mostly exposed. This is the reason the cooling air inlets are moved outward from the base of the propeller. My M20L with the IO-550 conversion has the Ovation cowl and the same alignment issue. At some point it would be interesting to see if the engine alignment matches the factory spec, but my suspition is that the cowling was aligned more with the fuselage than the engine, and the design doesn't fully take into account the down angle on the engine mount. The down angle on the engine will reduce the pitch up with addition of power, which is already a bit of a hand full on the long bodies during a go around. I'd rather have the engine at the correctly designed angle than the worry about the cowling lining up, but it's probably not much difference either way. Ben 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted February 20, 2021 Report Share Posted February 20, 2021 Let’s review.... 1) engine sag occurs with time... there are shims for that like any other engine... 2) O3 powered airplanes with Hartzell TopProps have a spinner dimension challenge... the spinner doesn’t match the cowling... 3) So... if your engine sags, get it shimmed... there are methods of measuring this in case you are unsure... 4) Hartzel promised a spinner of appropriate dimensions... see if they ever came through on that promise... 5) Yes, sag would be a performance problem... Level the plane, level the engine... good to go... Did I get everything? PP thoughts only, not a mechanic... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
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