Chapter 23 - Engine - Getting everything together

Cowling Lips

Plans say you have to fit the engine before you can fit the cowling. However, I'll be making my own cowling around the 13B engine, so I did a few things backwards. Rather than the lips and strake fairings being made to fit the cowling, my cowling will be made to fit the support lips and strake fairings. I just hope I got the fairings right. I fitted blue foam around the edge of the firewall, top and bottom strake fairings and across the spar to the wing roots, then glassed a 3 inch 4 ply BID tape all around the edge. I didnt do the wing root lips yet because I'm considering using hinges here. There wasn't much of an indentation along the spar and I hadn't made one in the fairings (I forgot), so the tape is a little proud of the overall shape. It wasn't a problem to fair it in.

Once the cowl lips were done I went back (or forward) to Chapter 25 to do primary finishing on the canopy, then to Chapter 15 to do the firewall. Chapter 16 and 17 snuck in again while I refitted the control linkages, finished off the rudder cables and fitted the electric trim.

Note: I made the cowling later. See Covers & Fairings

Cowling Lips - NACA Scoop

In March '01 I finally got the airplane upside down again for final finishing. The first step was to construct the lower part of the cowling lip which forms the end of the NACA scoop. Plans say you can do this with the airplane right side up, but I bet its much easier upside down. I started by carving blue foam (I'd run out of urathane and I'm getting quite experienced at carving the blue stuff). The plans seem a bit confusing here. They say to use a 2 inch thick piece of foam, but the diagram shows the airfoil itself to be 2 inches wide. I used 2 inch foam per plans including the 1 inch lip, so my airfoil was only 1 inch wide. I microed some more foam on the front and carved again. I'm describing this item as an airfoil cause that's what it looks like. Hmmm. A wing has low pressure on the "upper" surface. The way this item is drawn it looks like a mini wing. Low pressure at the top would such air into the cowl. Makes sense to me. I made it look as much like a wing as I could. Getting a good shape on a small piece of foam isnt easy, so I hard shelled it with micro, then glassed per plans. At each end of the wing I had to cut away part of the cowl lip I'd built previously to get a continuous lip. I covered the glass with a thin layer of dry micro and sanded for a smooth finish. Char came out to admire my work and said "it looks like it's always been there". I think that's a compliment.

Engine Mount

I felt a bit overwhelmed by all the work needed to install the engine, so I took Tracy Crook's advise and decided to deal with it one step at a time. The first step has to be the engine mount. Immediately the issues of C of G and prop extensions raised their ugly heads. I started by getting the dimensions for a standard lycoming 0-360 mounted in a Cozy. Nat gave me some numbers which helped a great deal, and Jeff Russell was kind enough to measure his plane for me.

The distance from the firewall to the flywheel on Jeff's IO-360 installation is 31.75 inches. Jeff has a 2 inch flange and an 8 inch prop extension making the distance from the firewall to the forward face of the prop 41.75 inches. Nat tells me that the plans engine mount is 10.5 inches, the distance from engine mount to flange is 22.2 inches and the prop hub extension is 8 inches giving 40.7 from firewall to prop. I got the following numbers from Nat:

A, Firewall to mount point = 10.5 (plans)
B, Mount point to engine flange = 22.2 (plans)
C, Length of prop extension = 8 (measured)
D, Firewall to prop = 40.7 (calculated)
E, engine C of G to engine flange = 14 (estimate)

And the following numbers from Jeff:
A + B, Firewall to flywheel = 31.75 (measured)
C, Length of prop extension = 10
D, Firewall to prop = 41.75 (measured)
E, C of G to engine flange = 14
F, Firewall to engine C of G = 18.75
From these numbers it seems that, either Jeffs engine is one inch further back than Nat's, or we have a minor measurement error. I suspect the later. Anyway, I think the ideal distance from firewall to forward face of prop is about 41 to 42 inches, and the plans engine C of G is about 18.7 aft of the firewall.

Nat says that the 0-360 Lyc weighs in at around 310 not including prop extension. I weighed my '93 13B REW and accessories on a UPS scale as follows:

Engine less oil pan    178
Smog pump                7
Starter                  8
water pump              10
Alternator              11.5
total                  214.5
Add in the redrive at 35 lb, the mount plate at 5 and about 5 lb of water and we come to about 260 lb for the 13B compared with the Lcy at 310. Of course there will be other items like prop extension, oil and mount, but these will be about the same on both. So, if we have a difference of around 50lb, does this mean I should mount the 13B aft of the plans point for the Lyc to keep the airplane C of G in the same place? If the recommended engine C of G is x inches from the aircraft C of G how far aft should the 13B go back to compensate for 50 lb? Hmmmm. I'm thinking that I might be able to move the engine back and shorten (or do without) the prop extension. ....or perhaps I'm being a bit anal trying to calculate all this stuff. So be it. The plans engine C of G is 18.7 aft of the firewall. Given Lyc weight of 310lb this equals a moment on the firewall of 483 ft lb. The 13B weighs 260lb. Lets add 20lb for some extras. Say 280. To get the same moment the C of G of the 13B needs to be 20.7 inches from firewall (2 inches aft). If we use the 260 lb figure the C of G goes at 22.3 The 13B is a small, short engine. It will be interesting to see where this puts the prop flange. Interesting stuff. I hope I get it right.

Ed Heishman - the problem Solver

That's Ed with his back to the camera click to enlarge Fellow Cozy builder, Bulent, has been talking to Ed Heishman (954-784-0134) about getting a mount made. Ed runs an engineering shop in Pompano beach. He's done quite a bit of airplane work (some of which I've seen personally) and has very high recommendations. In December '00 I contacted Ed and made an appointment for Buly and I to go down and see him with all our parts and calculations. When picking the time, I said I'd like to get started early. Ed suggested 4am. Hmmm. His business card lists his title as 'problem Solver'. I think I'm going to like this guy! We agreed on 8am. In preparation for building the mount I took another look at the Barry mounting Bulent and I are planning to use. It has a 1.25 inch diameter shank, so the lower mounts are going to be impossible to get in unless the center of the lower mounting points are moved up 0.3 inches from the plans position. Rather than bolting firmly to a hard point, the Barry mounts are rubber shock absorbers which grip the firewall from both sides with a compressed 2 inch donut of silicone rubber. The inside lower aluminum hard point reinforcements will have to be removed to permit the donuts to clamp the firewall as they were designed to do, otherwise the combined firewall and hardpoint will be too thick. I loaded the engine, false firewall and redrive into the truck and drove down to Pompono Beach.

Bulent, Ed and I worked for about 9 hours to get the engine firmly positioned where it needed to be in relation to the false firewall. We began by marking off the engine mount points and center of thrust on the firewall. Next we installed the Barry mounts and washers. The firewall was aligned at 90 degrees to the metal work table and bolted firmly in place. Bulent had prepared a 1/4 inch AL plate to go between the sump and the engine to act as a mounting support. After match drilling a few holes, this plate was installed and the engine suspended in rough position. Vertical position was set with the thrust line at WL 21.5 (1.5 below the top of the longerons). Now came time for positioning forward and aft. I had calculated that we wanted the C of G 20.7 inches from the firewall. Bulent knew we needed the prop flange at 41 inches. There was a lot of discussion as to which measurement should direct the position. I felt that the prop flange position should be adjusted with a prop extension. Bulent suggested that the C of G could be moved by alternate battery placement. I argued that I'll be using a very light battery and I know where I want it. I won the debate and we positioned the engine C of G 20.7 inches from the firewall. Once we had it in place we measured the position of the prop flange. Wow. Thank you Tracy Crook. You made the redrive the perfect length. 41 inches on the dot. We spent hours making minor adjustments to all three planes using rulers, a spirit level and angle finder until we had the engine perfectly placed horizontaly, verticaly and fore aft. As we got each plane correct, Ed ran around welding steel bars to the metal table to hold everything in place. Ed uses welds like like most of us use clamps. We added a 1.5 degree angle to the thrust line (prop higher than firewall end) to counteract the angle of the fuselage at cruise. Later Ed suggested that we change this to 2 degrees. Why 2 degrees? "Everything sags!", says Ed, "Everything!". We made it 2 degrees.

While all this was going on, I had a problem restarting my big old Suburban truck and had to install a new starter, then a battery. At one point I came back to the truck to find Dion Curtis, who works in a nearby shop, under the truck. He just decided I needed some help and pitched in. What a guy! With Dion's help and Ed's tools I eventually got back on the road.

We left Ed with the engine fixed in place, ready for him to build the mount. He will be making two, one for Bulent and one for me. He'll build a jig around the first one so can make a second identical unit. If you're planning to mount a 13B to your Cozy IV using Tracy's redrive, now might be a good time to call Ed (954-784-0134) and have him build one for you. The more the merrier!

Ed took a while to get around to making the mount. I dropped in a few times to "shake his tree" and finally, one day in March '01, I actually caught him working on it. The mount was completed on April 1st. Hmmm. I drove down to Ed's in my truck to collect the mount and engine. To my untrained eye the mount looks like excellent work. It weighs in at 16 lb including the 1/4 aluminum plate which makes up almost half the weight. Ed had painted the finished mount with black epoxy paint, and even added a welded steel stand to the firewall. Ed tells me that he already has another order for a Cozy mount.

An alternative which has since surfaced is Fred Breese at Conversion Concepts As of August 2002, he makes a nice looking production 13B mount for RVs, and is working on one for the Cozy IV. In retrospect I think I'd prefer Fred's setup with the rubber mounts on the oil pan plate, and it sure would have been easier to just call and order, rather than invent. Of course someone has to fly the first one, but things are improving in Wankelworld!

A little more on the engine mount

A few builders seem to baulking at the price of the Conversion Concepts mount and want to weld their own. I've heard that welding chromolly steel is a black art learned over many years, but they said that about building airplanes too. Anyway, someone asked for more dimensions on my mount so they could copy it. If I were doing it again I'm not sure I'd go with the bushings on the firewall. They're complex to make, and the bottom ones are being compressed by the weight. It flys fine, and I see no signs of problems, but perhaps the bushings on the mount plate like Conversion concepts is a better plan. Whatever you do, don't build the thing that Lamar recommends without talking to an engineer first. Also check Tracy Crook's opinion about fitting the mount to his redrive plate.

Anyway. The dimensions of my mount shown in the picture are:

A - Long top tube - 26.5
B - Short top tube - 17.5
C - Short lower tube - 18.5
D - Long lower tube - 27.5
E - Vertical tube - 15.5
G - Mount plate - 15 (fore aft) * 16 (width) 1/4 al plate
F - Firewall to forward face of flywheel - 27.7
The above figures are approximate for the longest part of each tube. The mount points on the firewall are per plans, except that the lower two are about 1/4 inch inboard to make room for the bushings. If you look at my weight and balance figures calculated in the prefilght section, you'll see that it wouldnt have hurt to have the engine an inch or so closer to the flywheel. For relatively light pilots like myself this would have reduced the amount of solo ballast needed.

Back to Rotec Motersports

I drove straight from Ed's shop to see Chris Harris at Rotec. Chris built the engine. Now it's time for him to get it running. Sure - I could probably do a lot of this work myself, but I don't want to make a mistake with the area most likly to cause an engine stoppage - the periferals. I decided going in that I wouldn't skimp on expense, and I'd use professionals for all the critical engine work. Things like the water pump (Chris says I need a new one). We discussed the next step and agreed that Chris will now add the radiator, oil coolers, smog pump, EFI computer (from Tracy), water pump, alternator, starter motor, air conditioning components, stock intake system, stock exhaust manifold, injectors, ignition wires, coils etc. etc. etc. to the engine on the false firewall. In effect get the sucker running using stock parts and plumbing as necessary. Once we have it running I plan to take it back to Ed for design and construction of an exhaust and intake system to replace the heavy stock items. There are still a few issues to solve - such as aviation quality water and oil plumbing (see below), information and warning sensors (see below). While unloading the engine from my truck I was caught off balance and ended up with my hand between the flywheel and the bench. The flywheel teeth ripped good sized chunks of skin off three fingers. Ouch. Another aviation injury.


I saw an ad for Avcells in a flying magazine which said they'd just opened a shop in Ft. Lauderdale. These guys make up aviation hoses to order. I called them and asked if I could bring my engine assembly & firewall around and have them do the plumbing for the whole thing. No problem, they said. This SHOULD be my solution to getting good aviation quality hoses made for the oil and water.

Engine instruments

While at Sun & Fun '01 I came across Ralph Krongold and his I-K 2000 Flight Engine monitor. See Chapter 22 - Electrics

Gold digging for information

Also at Sun & Fun I heard of a Cozy III which is currently going through it's 40 hours with a Turbo 13B on the back. After a few enquiries I discovered that the owner is Greg Richter. The aircraft is based in Merritt Island, FL so I drove up and visited. For those interested, I've provided a full write-up of this visit.

Configuring the engine

After seeing Greg's plane I got all fired up to get my own engine fired up. I arranged with Chris Harris to meet him at his shop and spend a day working on it with him. I took the day off work, only to get a call at 10:30 the night before cancelling the appointment. Chris told me he had other commitments that day, but suggested opening the shop on Sunday when he would be able to dedicate all his energy to my engine. Seemed reasonable. I knew we'd need the EC2 computer, so I stayed up to nearly 3am soldering the connections on the two connectors and making the wiring harness (see Chap 22 - Electricl). I had arranged to have Sunday off work. I got up early and drove down to Ft. Lauderdale in my truck at the appointed time of 10:00am. By 10:30, when there was no sign of Chris, I called his cell phone only to get a message system. It was hot and uncomfortable sitting in the truck outside the shop, but I was determined to get this done. By 11:30 I was beginning to wonder if Chris had gone out of business. But then, I know Chris. He's "from the islands" and time has a whole different meaning to him. But - he had my engine, mount and redrive inside his shop. Not good. I have a lot invested in these parts. I'd hate to loose them and have to start from scratch. I looked at the door and considered how easy it would be to pull it off with my truck. I even had a tow rope in the back which would be ideal for the job. Hmmmm. By 12:00 I'd left Chris half a dozen messages of increasing levels of directness, and had Char send him a fax and a couple of emails. I drove away from the shop angry and disgusted. I resisted the temptation to pull the door off his shop... for now.

I dropped in to see Buly at Ft Lauderdale Exec on the way home - he was at lunch - and gave Chris a final call at 12:30 pm before heading North. He picked up. He'd been up late the night before and had just woken up. He needed some time to eat and get a shower. He'd meet me at the shop in an hour. I drove back to the shop and waited again. Chris finally showed at 2:00 pm and announced that he had to be somewhere at 4:00pm. Damn. To his credit he worked until 7:00pm, but we were interrupted a bunch of times by "Mazda junkies" with their race tuned RX7's. They needed Chris to adjust the carbs etc. etc. It was nice to hear a 13B run, but unfortunately it wasnt mine. We had to cut a hole in the AL sump plate for the oil pickup. Next we had to take a run to the hardware store [which was closed - it was Sunday] for some bolts. Chris was thirsty, so we had to stop for a couple of beers. Well - it was Sunday after all. Eventually we assembled the sump and sump plate onto the engine. We didn't seal it because we didn't have all the bolts. By then it was 7pm. I explained to Chris how I need the engine, redrive and mount at my house so I can make the cowlings, so we loaded everything into my truck and I politely said goodbye. Chris agreed to come up to my house and do the work there later. Chris is basically a good and honest guy who knows his stuff. Unfortunately he's (always) very backed up with work and its hard to get his attention. On top of this he lives in the USA, but on Island Time. I needed to get control of the project, so now the engine will be configured at my house. If Chris can get up there to do it when I need it done - wonderful. If not, it'll get done anyway, and it'll get done under my supervision and in my time schedule. I may even end up learning enough to do it myself. The engine now sits, mounted on the false firewall and on it's stand next to the hot tub. A hell of a conversation piece.


[Note - I refer to quite a few contacts in the following paragraphs. See my links page for how to reach these people or companies

I had planned on going NA (normally aspirated), but I liked Greg Richter's logic concerning using a turbo. It's a relatively simple way to quiet the exhaust and get rid of the heat. What I didn't like was the price of his Turbonetics unit. The trouble with the stock turbo for the 3rd generation 13B is that its a complex twin turbo setup which is quite heavy. During discussions with Paul Lamar on his ACRE website I found out that the single turbo on the '89 - '91 2nd gen engines was an excellent piece of work. It is relatively light and simple, has water cooled bearings, and it fits my '93 engine. Paul told me that he and a number of other builders are planning to use it. The Mechanair firewall forward engine from Switzerland is using it. I'm not sure if anyone is flying one yet. I decided to try and locate one. The bad thing is that they're fairly rare. I found one in "oz" at Japperformance for US $424 inc. shipping. The next day, Bulent called. He'd found one locally at a better price so I snapped it up.

That evening, while in the hot tub Char and I were looking at the engine and discussing the turbo. I decided to see if it would fit. This is probably the first time a 13B turbo has been assembled by a naked engineer. I slid the turbo onto the exhaust studs (two of which are missing). It fits beautifully. It barely misses the mount, but it does miss. Next I put the alternator in place and slid the redrive on. Hmmm. I got the starter and smog pump. This is starting to look like an engine. All I need is a few radiators and tubes and I'm done. Well, not quite - but I am starting to see some progress.

Getting the extra bits

One evening I was browsing around the web trying to figure out where I could get all the extra bits I need. On Tracy Crook's web site I came across Bruce Turrentine (919) 212-0671 who rebuilds Mazda engines for aviation use. I was thinking how much trouble I'd have saved myself if I'd gone straight to Bruce, when I saw a listing of his "accessory kit". Accessory kit includes: Stock Pulleys, Water Pump Housing, Injectors, Injector rails, Stock intake and Throttle body, Crank Angle Sensor, Oil pan, Dust shields, Bolts related to listed components. The price of $125 was for a 2nd gen engine, but it occurred to me that Bruce might be able to provide a similar kit for my 3rd gen. I called and got Bruce himself. We spent a half hour discussing my list of missing items punctuated with him saying "I've got one of them!". My list included "'90 stock all aluminum intercooler, stock 2nd gen oil cooler, 3rd gen smog pump, exhaust studs, sump bolts, stock engine mount bolts, alternator tension bracket, a/c brackets, pulleys and stock turbo exhaust flange. We discussed the '90 turbo on a 3rd gen turbo engine with high compression rotors and bruce confirmed that this is an ok configuration that he's used himself a number of times. He says I should limit the boost to about 6PSI and recommends building an inconel or SS manifold to get the turbo a bit farther away from the engine. This will help with heat dissipation and the construction of an augmented exhaust heat shield. When we got to talking about the intake things got REALLY interesting. It turns out that Bruce is almost done with a high temp tuned fiberglass intake manifold which will come with injector rails, injectors, throttle body and inlet flange. He will supply adaptors to make it fit the various 2nd and 3rd gen configurations. What could be better than this? Well.... The first one is going to Tracy Crook in a few weeks, and Tracy is going to put his butt on the line to test it for us. What a guy! Bruce agreed to put together a grab bag list for me and send it via email. I'd better get moving with the finishing and painting. The engine seems to be gaining on me.
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