Re: Q2/200 Engine mounts

Bruce Crain

With the Seawind 3000, is “thrust line” really a thing?  Isn’t it really a way to get the engine to fit the cowl?

On Feb 10, 2022, at 11:32 AM, smeshno1@... wrote:

 Now I am curious now to see where my Crank C/L will end up, close to or not the Q-200 and your 3300. Having the C/L of the 3300 that close certainly makes anyone looking at an O-200 replacement seriously consider the swap! Time to get out the measuring stick.. 

 Is your engine rotation a factor in your placement of the NACA? By that I ask..the leading blade propeller blast or are you looking more for installation ease?  In my case the rotation is clockwise looking from the front..the remote cooler usually is on the Pilots side firewall so the NACA for ease of installation would be on the lower Pilots side cowling. Better for airflow is the Port side lower cowl area! The cowling would be blanking the more effective air blast on the ramp if the NACA was in place for ease of installation.    

 Considering the oil cooler. My plan is using my firewall mounted remote oil cooler (which is required on my engine) as the Winter interior heat source rather than risking an exhaust exposure as I had opportunity to "enjoy" in flight several times with the Cessna's I've owned. Still plan to keep the monoxide indicator.   

 Exactly the same in mind about drag reduction. 

 The NACA will have to be sized to be effective but going larger than required and adding a cowl flap feature would resolve my concerns. As you know here in the Midwest the temps become rather oppressive in Summer, and in extended climb and possibly waiting on the runup ramp in Summer as I mentioned, I'm expecting to have some higher than preferred oil temps. That is why I am designing a NACA + inlet cowl flap design.  

 Of course Winter ops demand the oil temps to remain in the green as well, even in extended decents. Head temps I have no concern about.. the oil temps are another story. I had issues here in my O-200 powered 150 on extended climbs.. it was not at all entertaining watching the oil temp needle climb ever closer to the redline in Summer, especially knowing the valve guides tend to get coked oil in those conditions. Next problem from that..stuck valve!!  So the only solution was to step climb which is not the best option other than over open countryside.    

 I'll be installing an Ellison TB..a new one from the authorized dealer. Decided against the Marvel simply because the economics of rebuild is not there anymore and the Ellison is already a proven unit for the engine. I will stay with gravity feed from the header..twin low pressure faucet pumps (one backup, one active) to pump forward from the main, same as Charlie Johnson has.    

 Best regards, Vern

From: <> on behalf of Jay Scheevel <jay@...>
Sent: Thursday, February 10, 2022 11:35 AM
To: <>
Subject: Re: [Q-List] Q2/200 Engine mounts

Hi Vern,


I got the thrust line on the 3300 pretty close (+/- 0.2”) to that of the O200. I was able to use my original Q-200 cowling halves with not too much alteration, other than the self-inflicted issue of building the radiator ducts. Sometime down the road, I will probably slice off the forward scoop that was used for the carb intake on the O200 and serves as the oil cooler intake on my engine. I can clean up the drag by doing this, so it is on my list for down the road. Won’t affect the oil cooler, since I will install a NACA duct on the bottom of the cowl, which actually will be better for cooling during climbout.





From: <> On Behalf Of smeshno1@...
Sent: Thursday, February 10, 2022 9:34 AM
Subject: Re: [Q-List] Q2/200 Engine mounts


 Just curious Jay.. was your 3300 also at the O-200 thrust line or did that change? I know for sure on my engine choice 

the supplied cowling is not a useful item. I will be hinging in 4 sections. 2 up and 2 down.  Different materials and 

construction process.  



From: <> on behalf of Jay Scheevel <jay@...>
Sent: Wednesday, February 9, 2022 10:14 PM
To: <>
Subject: Re: [Q-List] Q2/200 Engine mounts


I computed the vertical position of my empty CG when I was doing my weigh and balance by changing the angle of the fuselage from zero and recording the difference in scales and FS’s, then computed the vertical CG from those. I will see if I can dig that up. I also did a measurement of the difference between the thrust line of the Revmaster and the O200. They are not the same. Will see if I can find that also. 




On Feb 9, 2022, at 9:03 PM, Ian Ashdown <ian.ashdown@...> wrote:

I don’t believe the design O-200 thrust line is WL 15” but the only dimensional reference I’ve found states that it is 7.6” (I think) from the top of the firewall.  Don’t you love the use of consistent datum’s!  My question is, is that the firewall panel (inside of the Fuse) or the outside of the fuse at the FS 14” (firewall)?

Very confusing/frustrating!


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