MTV-12-B Spinner

I was making a spinner template last night so that I could start fitting my cowling. I didn't really think about it last night, but as I was laying out the board I had an issue with fitment. (don't mind the non-concentric circles, in the quasi-center of those dots are the real layout points)

The issue I had is that I started with the outer circle (15").

Thinking that I was just mis-remembering the spinner diameter I grabbed the spinner and laid out another line.

That went fine and everything bolted right up to where it should have been. But something still did not feel right. I went over to the show planes website and low and behold, the cowling is designed for a 15" spinner. So that is a bummer. I am not sure where the mix up was, but I think it all started with me assuming that all MTV-12-B spinners were 15".

I guess I have my first parts mix-up.

MTV-12-B Dimensions

One of the weekend tasks is creating a jig for the cowl fit up to take the place of the prop and spinner. I read a while back on the reliable internet that the distance between the spinner plate and the hub flange was 40mm. I did not want fit my cowling based on some internet numbers so I waited for my prop to arrive so I could take the measurements myself.

The first measurement I made was to the aft spinner cap. This looked to be 1.9". At this point I was completely assuming that the spinner itself was going to end flush with the aft plate.


Going to the manual, you will see that this is not a good assumption. When you fit the spinner onto the assembly you see that the spinner extends beyond the aft plate. With the spinner installed, there is ~1.55" between the aft most part of the hub flange and the spinner. I would really like all these numbers to add up, but having triple checked my setup, 1.54" (39mm) is the number.

Mounting the Engine!

With my parents in town and my dad ready to spend some time in the garage, it was finally time to hang the engine. The long story short, this was a lot easier than the stories I heard with the motor mount not lining up to the mounting ears. With the engine load leveler on the hoist, this is actually a one person job (its not like you are trying to get the engine bell housing bolts in place while laying under a car!)

I would say the thing that took the most amount of time was getting the lower mounting ear bolts torqued. Not that it was impossible, it was a bit annoying and I ended up taking the rear down tubes off of the sump to get at the nuts.

I am happy to say that everything fit first try. That said, I am going to pop the engine off and re-weld my cross bar on the engine mount. I previously lowered the cross bar in order to clear the sump. I will admit, that when I measured everything up, I never fully mounted the engine mount to the engine. I was looking for about 1/2" of clearance, which I did end up getting... And then I torqued the engine mounts and took the weight off of the engine. I ended up with about 3/32" of an inch when all was said and done. While that may be fine, there is no reason not to re-weld this because it is going to take me all of an hour to take the engine off and put it back on. Plus, since I have procrastinating some building I have been doing a lot of 4130 TIG welding to keep my skills up. 1/16" 2% ceriated tungsten with some 1/16" ER70S-2 does a much better job than my previous 3/32 setup.

Mounting Ear Torque

I have read a couple of posts on people not being able to get a torque wrench on the mounting ears. I figured I would go with the calibrated arm as well, until I uncrated the engine. All four of each of the mounting ear bolts are reachable with a torque wrench and some torque adapters. Just remember that torque adapters are to be used 90 degrees to wrench as not to multiple the length of the arm.



This was fine and dandy for the top ears. The bottom ears are another story. I ended up removing the rear intake tubes and torqued the forward facing bolts with a combination of an open-ended crow-foot adapter, 3/8 u-joint, and 6 inch extension.

B&C OIL FILTER ADAPTER KIT and FS1-14B (Continued)

To use the B&C Oil Filter Adapter with the RV-10, one needs to use the 1.4" spacer kit in order to clear the engine mount. The 1.4" spacer kit comes with 4 new bolts of the proper length. This does mean that the one stud that was originally in the engine case needs to be removed in order to use the new (longer) bolt. While this should normally be an easy task (especially on a new engine), I could not get the stud to budge. You probably know where this is going, but I ended up breaking off the stud after a couple of attempts to double nut this thing out of here.



















At this point I only had 3/4 of a nut of thread length left. I could have put a vise grips onto this and hoped for the best, but in not wanting to have to drill out a stud I opted to weld a nut onto the stud.



In order to locally ground the nut and stud I put a vice grips onto the nut and grounded the vise grips. Based on the layout, the TIG arc jumped to the vise grips a couple of times which caused the smoke you see in the next photo.



All in all though, this worked out well. The stud still came out pretty tough, so I am glad I took this approach rather than risk getting the stud broken off flush.



With the stud out I could now install the spacer, adapter, filter, and alternator. PlanePower has listed right on their website that using spacers larger than .75" may interfere with the FS1-14. I could not find anyone that had any good photos of this combination, so figured "may interfere" would be workable.



As expected, the alternator does in fact interfere with the adapter (in two places). The first place is the safety wire ear on the adapter. This is not really that big of a deal because one could either clock the alternator differently, or grind off the ear (as there are two ears on the bracket).



The next interference point though is a bit more interesting. If you look at the top right bolt in the oil filter adapter you will see that it is perfectly lined up with the boss on the alternator. Each one of the four clocking positions of the alternator line each one of the 4 bolt bosses up with this bolt. A quick and easy fix for this would be to file 1/4" off of the boss. This part of the boss is not even threaded and I am pretty confident wouldn't hurt the structure of the alternator housing.



I debated this for a while, and I am going to scrap the idea of putting the 90 degree adapter on and keep the original straight oil filter housing. My mine thinking on this is two fold. One, the adapter does add another gasket and another place for oil to leak. More importantly though is if I went down the path of modifying the alternator housing, this means that if I ever needed to replace the alternator, that I would have to again make the modification. That is fine and dandy until you are on vacation stuck at some random airport hand filing down an alternator housing.

B&C OIL FILTER ADAPTER KIT and FS1-14B

With the engine still off it is a good time to get the backup alternator and 90 degree oil filter adapter. I ended up going with a Plane Power FS1-14B backup alternator. I am still working on my electrical system, but I am planning a two alternator two battery system. Only 1 alternator will be enabled at any given point in time and the selection will go back to a toggle on the panel for PRIMARY or BACKUP.

Original Oil Filter setup with the block off plate on the vacuum pad.

Removal of the block off plate

With the FS1-14B installed (temporarily)

There is actually a fair bit of room between the oil filter and the alternator. It does have me wondering if I need the 90 adapter or not. From the people who have gone down this path, it seems like everyone is on the same page that the oil filter without the adapter is a pain in the but to replace. It is just hard to see that at this point (when I have 360 access to the engine).

I already have the B&C adapter, although I did not purchase a space plate yet. I was not sure what size space I need so I figured I would fit everything up first and then take care of the spacer.

Eagle CAD

I really needed to get more of my electrical design done in order to make some decisions on wire pulls and panel configurations. I have access to Solidworks (as do all EAA members) and I started going down the path of expanding my electrical schematics from the Aeroeletric design repository. I think most people end up going down that path or even take the simpler approach of powerpoint. 

For me I draw a lot of electrical schematics and board designs for work and I typically use Eagle or other similar electrical design tools. I personally am more comfortable using CAD software in 3d (which doesn't make sense for electrical schematics). I am also much more comfortable in the organization and layout of electrical schematics in an electrical schematic tool (which for me makes debugging much easier).

So I decided to pay the upfront cost of using Eagle to layout my eletrical system. I started creating "packages" for all of my components so that I can appropriately make the pin connections.



I still have a lot of layout to do, but for the most part I have the rough components and pins built into my library now.