Mazda 13b w/ Tracy Redrive

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narfi

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I have seen this advertised before. Does anyone know the story behind it? Is it worth making an offer on? What is fair considering I want to be as 'cheap' as possible and don't mind waiting a year or more before finding what I need.

I am scratch building a Zenith Super Duty with my son and would like to end up in the 200+hp range. I have always been fascinated with the Mazda conversions but PSRUs have been what concerned me the most. I know the Tracy ones have a good reputation so this seems like a good start for me to get going toward collecting everything I need....

Would love advice from those smarter than me.
Thanks!
 
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rv7charlie

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I've got Tracy's drive & engine controller; both are quality products. But there's always a but (often more than one).

The 1st and most obvious is that the Zenith 750HD page lists FWF packages for: 'ULPower series, Continental O-200, Jabiru 3300 and Rotax 912 ULS engine'. All of those engines are *much* lighter than a 13B rotary installation can ever hope to be (and much lower HP output, obviously). Is the design approved for 300 lb+ FWF weight, and double the HP of the recommended engines? Will you have any payload left after installing the engine and enough fuel to get you out & back when bush flying?

2nd, you'll need to not just build, but *design* a motor mount; not trivial tasks. You may have the skill sets or access to those skill sets; I was fortunate to have a couple of mech engineer friends who could also do a/c quality welding.

3rd, Tracy made two different ratio gear boxes; some with 4-planet gearsets and others with 6-planet gearsets. If the one in the ad is the narrow ratio box, you'll never see anywhere near 200 HP from the engine; the engine can't rev enough to make its full HP potential with the narrow ratio box. You need the 6-planet set (wide ratio) for 180+ HP engines. He also made at least 3 different versions of the controller. Obviously, the later ones are improvements over the earlier versions.

4th, Tracy's stuff is high quality, but no rotary installation is 'plug&play'. You'll need to develop both an intake and exhaust system (both critical on a 13B to make real HP, and a Masters Thesis in themselves), and a cooling system that will work at that high HP level in a very slow a/c like the 750 (another Masters Thesis). Your 3rd Thesis will come in setting up and tuning the controller.

Not trying to be a Debbie Downer; I like rotaries and I'm installing one in an RV7. But we do need to approach this stuff with all available info considered.

FWIW,

Charlie
 

narfi

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I've got Tracy's drive & engine controller; both are quality products. But there's always a but (often more than one).
Thanks, appreciate it.

The 1st and most obvious is that the Zenith 750HD page lists FWF packages for: 'ULPower series, Continental O-200, Jabiru 3300 and Rotax 912 ULS engine'. All of those engines are *much* lighter than a 13B rotary installation can ever hope to be (and much lower HP output, obviously). Is the design approved for 300 lb+ FWF weight, and double the HP of the recommended engines? Will you have any payload left after installing the engine and enough fuel to get you out & back when bush flying?
I believe you were looking at the 2 place 750STOL not the 2.5 (2+jump seat) place 750 Super Duty....
1100lbs empty with a 300+lb engine in it and 1900lb gross.
Perhaps I am wrong, but it 'feels' like a properly configured Mazda engine would be right in this weight and power range?

Zenith Super Duty Information Page said:
The Zenith Aircraft prototype STOL CH 750 SD is powered by a 205 hp IO-375 engine from Aero Sport Power. Like all Chris Heintz designs, the Super Duty is not designed around any particular engine, which gives you the freedom to choose the engine that best fits your performance needs and budget restrictions. The suitable range is 150-230 horsepower.
Viking Built a 750 Super Duty to showcase their engine,
and says it is 260lbs not counting intercooler and radiator which would bring it close to 300lbs.

2nd, you'll need to not just build, but *design* a motor mount; not trivial tasks. You may have the skill sets or access to those skill sets; I was fortunate to have a couple of mech engineer friends who could also do a/c quality welding.
I am not arrogant enough to attempt that at this stage of my experience level, but I have access to a friend/coworker who does lots of aircraft welding, years of rebuilding Stinsons, cubs, etc..... he is currently rebuilding a Stinson JRSR and a Pacer. If he does not have the time or feel comfortable, I would do the preliminary work and get F. Atlee Dodge to do the welding for me. (not cheap, but high quality)

3rd, Tracy made two different ratio gear boxes; some with 4-planet gearsets and others with 6-planet gearsets. If the one in the ad is the narrow ratio box, you'll never see anywhere near 200 HP from the engine; the engine can't rev enough to make its full HP potential with the narrow ratio box. You need the 6-planet set (wide ratio) for 180+ HP engines. He also made at least 3 different versions of the controller. Obviously, the later ones are improvements over the earlier versions.
I sent an inquiry to the seller, and he is not interested in crating or selling to anyone not in person. However I did reply asking for more information on the gearbox and what ratio it is as well as if he would be willing to sell it separately. I need to research more again, but was the higher ratio one 2.85:1 ?

4th, Tracy's stuff is high quality, but no rotary installation is 'plug&play'. You'll need to develop both an intake and exhaust system (both critical on a 13B to make real HP, and a Masters Thesis in themselves), and a cooling system that will work at that high HP level in a very slow a/c like the 750 (another Masters Thesis). Your 3rd Thesis will come in setting up and tuning the controller.

Not trying to be a Debbie Downer; I like rotaries and I'm installing one in an RV7. But we do need to approach this stuff with all available info considered.

FWIW,

Charlie
Not a Debbie Downer at all, Realistic which is what I need.
However, you probably need a bigger club to beat some sense into me.......

I don't like doing things the easy way, and I do not mind work and thought and study. (I actually find them enjoyable and therapeutic) That is why we are scratch building a plane they have not released scratch build plans for yet :)
Here is my mindset,

1. Building up an engine with the right accessories and porting etc..... a 'butt' that I can work with
2. Exhaust and Intake..... a 'butt' that I can work with
3. Mount.... a 'butt' that I can work with
4. Cooling.... a 'butt' that I can work with
5. Tuning.... a 'butt' I think I can work with
666. PSRU..... not something I should do on my own, I need a safe reliable one before considering the project....

I probably won't seriously need to be looking at starting an engine project for another 18 months or so, but I would like to make some decisions and start down a path. That will give me time to not only buy things at a relaxed pace and sort of 'self' budget over time, but will keep me from needing to panic buy a plug n play package when the airframe is done.

If I can find a good PSRU, it seems like the rest, while not trivial is at least doable by someone willing to do the research and groundwork.
Is this a bad plan?

If this is a good plan, what reliable PSRU should I be looking for that is capable in the 200-250hp range?
Thanks for any advice :)
 
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TFF

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I am of the opinion that if you find something you like and you have the money, buy it. Willing to deal with it is the only way something like this is successful. Of course it can be fun too.

You will have to accept all the wear and tear fixing will be you. I just had to source a seal for a helicopter that was not going on the production list for two months and the factory was out until then. Off the shelf number but the world was out of them. The one I found was probably on a shelf for five years. Just luck.
 

narfi

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So I got my answer back, he has the 2.17 ratio, which I already knew was smaller than I wanted.
He did ask if I would be interested in the EC2 and EM2. I don't know the answer to that yet, what are the options out there right now for that? Is that a good approach or are there more modern options that would be better? and if it is a good choice, what are they worth? They seem kind of archaic?
 

rv7charlie

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Good to know it's a viable engine, in both weight & HP measures. For some reason, when I pulled up a search for the a/c, the Zenith page that loaded listed the smaller engines (I actually cut/pasted from the web page into my post). For reference, my Renesis FWF, with everything including a heavy muffler (required) and dual 55A alternators, weighs ~335 lbs, dry. With one alt and some careful redesign, I could probably get it down to around 300 lbs dry. For comparison, an angle valve Lyc 360 weighs ~335 lbs, bare, before exhaust, oil cooler, etc. None of the weights include a prop. Tracy has always said not to expect more than about 90 HP per rotor in an a/c, due to the inherent limitations of the core engine in cooling the combustion chamber areas. They can be run harder than that (there are a couple of 'boosted' engines flying that make a lot more for short periods), but you can expect to have 'issues' long term. Temper that with the fact that almost everyone with a rotary runs a fixed pitch prop, and never runs flat-out at sea level. So even though the engine is capable of 200+ HP, the prop prevents you making full power on takeoff (rpm limits) and altitude (MAP limits) prevent making full power in cruise. So it can be the equivalent of an angle valve Lyc, if both are running fixed pitch props.

I agree that the drive is the most likely thing to be a 'show stopper'; Tracy leaving the supply chain is likely one of the biggest reasons for a downturn in rotary a/c activity. The 2.85 ratio is the one you'd want, if you use one of Tracy's drives. My *opinion* (worth what you paid) is that ~2.4 would be close to ideal for faster a/c; that would allow 'typical' prop diameters (around 72") and 'typical' prop rpm (2700) relative to Lyc standards, while the engine is turning in the mid-6K range. If the 750 can swing a larger dia prop (closer to 80"), then the 2.85 could work out great for you; big improvement in low speed mass flow with the bigger prop. Unfortunately, the only new production drive specific for the rotary that I'm aware of at the moment might be the Marcotte. If I were shopping for one, I'd try to get in touch with Aeromomentum to see if he would make one for the rotary. Based on his reputation, I'd have some confidence he'd be able to properly design one. There are a couple of future possibilities, including the sorta-clone of Tracy's from Down Under, but I don't think any are in production yet. Drive choice will drive everything else around the engine, because Tracy's and the clone are the only ones that are planetary-based. All the others I've seen have some degree of offset between E-shaft and prop center.

There are plenty of options for engine control; you just have to learn the new system of choice. Just saw your question about controllers. If the EC2 is the old square box, I wouldn't want it. I had one, and Tracy swapped it for a later, rectangular case EC2 instead of trying to update it. The last production version was the EC3. If I were starting with nothing, I'd probably set up dual MicroSquirts, or even consider carbs & electronic ignition. FWIW, I prefer the Renesis engine core to the older 13B, because it's a bit lighter and designed for more output in the car (through higher rpm operation). It's also more recent production, and finding a core engine that's in good condition should be a bit easier. The Renesis is a bit easier to set up, as well. The 13B intake *and* exhaust are both critical for making real power, but the Renesis is relatively immune to exhaust tuning. It just needs a free flowing, minimal backpressure system. So tuning is limited to intake design (not that that is simple).

Welcome to rotary world! And do join the Flyrotary list. It's not super active right now, but most of the builder/flyers are monitoring it for posts, and will jump in to help with any questions.

Charlie
 

narfi

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'typical' prop diameters (around 72") and 'typical' prop rpm (2700) relative to Lyc standards, while the engine is turning in the mid-6K range. If the 750 can swing a larger dia prop (closer to 80"), then the 2.85 could work out great for you; big improvement in low speed mass flow with the bigger prop.
The prototype 750 Super Duty I believe has an 82" prop, so 80-82 shouldn't be a problem :)


Unfortunately, the only new production drive specific for the rotary that I'm aware of at the moment might be the Marcotte.
The highest gear ratio I see on what I think is their website is 2.4:1

If I were shopping for one, I'd try to get in touch with Aeromomentum to see if he would make one for the rotary. Based on his reputation, I'd have some confidence he'd be able to properly design one.
I had emailed him in the past, but more tentatively, now that I am getting ready to start spending a bit of money I should contact him again.

There are a couple of future possibilities, including the sorta-clone of Tracy's from Down Under, but I don't think any are in production yet.
Is that this one?

Drive choice will drive everything else around the engine, because Tracy's and the clone are the only ones that are planetary-based. All the others I've seen have some degree of offset between E-shaft and prop center.
Other than the obvious advantage of higher centerline and more prop clearance what are the advantages/disadvantages to the two different approaches?

I'd probably set up dual MicroSquirts,
I had that in the fuzzy corners of my memory but I agree, that does seem to be a better more modern solution.

FWIW, I prefer the Renesis engine core to the older 13B, because it's a bit lighter and designed for more output in the car (through higher rpm operation). It's also more recent production, and finding a core engine that's in good condition should be a bit easier. The Renesis is a bit easier to set up, as well. The 13B intake *and* exhaust are both critical for making real power, but the Renesis is relatively immune to exhaust tuning. It just needs a free flowing, minimal backpressure system. So tuning is limited to intake design (not that that is simple).
good info, thanks!

Welcome to rotary world! And do join the Flyrotary list. It's not super active right now, but most of the builder/flyers are monitoring it for posts, and will jump in to help with any questions.

Charlie
I was part of a mailing list for a long time I just lurked in, but he died and his son started a forum that is pretty much empty in place of his info dump website(it seemed kind of heavy on theory and light on doing though...)....
How do I register for the flyrotary list?

Edit: Found the website, The Lancair Mail List Homepage and sent an email as the subscribe button wasn't working :)
 
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rv7charlie

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That's the 'down-under' drive I was referencing. You do need to get specifics on what he's using for a 'flex drive'; it's not Tracy's and it isn't specified on the linked site. He also made some significant changes in the bearings design; I'd want an engineer to go over that with me prior to purchase, as well. The 2.85 gearset is the same as Tracy's. The only issue that Tracy's box had was the input shaft thrust bearing was a 'stack' of roller bearings with a 1 mm washer between them (best he could do when he designed it, to get both thrust load and rpm ratings high enough. There are now single row bearings that are near-dropin replacements for the original double stack.

edit: Forgot to specify the issue with the stacked bearings. In *some* drives (not all) the super thin washer between the two bearings will 'orbit' and because it's so thin, it would eventually wear a groove on the input shaft. Never any failures from it, but it made some of us uncomfortable enough that a later tech single row bearing was found that could replace the stack.

You found the right place for the flyrotary list. If you don't hear back from the admin within a few days, PM me and I'll try to get his attention for you. He no longer owns a rotary, but continues to host the list. (Your impression of the other list was pretty much 'on the nose'.)

Charlie
 
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dwalker

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Neil Unger the fellow making redrives in Oz has (as of a couple months ago) a 3.17 redrive based around Tracys design sitting in Colorado for sale, brand new.

I am very strongly leaning towards the Marcotte PSRU myself, as it seems the most viable at this time. I have also considered (strongly) buying parts from Neil and having the rest of the bits machined to spec. This is an unlikely event, but still on the list.

I personally feel right now the best deal in a flight engine base from the rotary pool is to buy a new 13B-REW ( as fitted to the FD3S twin turbo) engine direct from Mazda, then perform the necessary preparations for flight. I raced the Renny for a pretty good time, and am familiar with thier quirks. The issue with them currently is there is no way to buy an all-new motor from Mazda at this time. That may be changing as part of Mazdas program to make new engines for out of production cars available again. I would NEVER trust a reman 13B from Mazda, as the subcontractors have changed several times over the years and there is no guarantee you will get a good reman, and certainly no way to know if the parts are new or "in spec used". For the money spent, buy new. Especially if you plan on a turbo application.

There are several approaches to turbocharging the 13B. My personal choice is to use a compound turbo setup using stainless steel turbine housings to offset some of the weight penalty. Alternatively, looking up the specs for the various Rajay aircraft turbochargers might be very useful.

I am using an AEM Infinity ECU to run my engine. I have a lot of time with this specific setup and have done beta testing for the manufacturer on several of thier products.This will be interfaced with thier CD7 display allowing monitoring and logging of all engine parameters as well as additional data channels.

I think cooling is always the bane of the rotary installation. One thing I think a lot of installers do is to forget they are installing the rads in an airplane and not a car, and so thought needs to be given to fin type, spacing, thickness, flow, etc. I would suggest talking to Ron Davis Racing Radiators for thoughts and input, as well as searching out tech articles on it. I myself am planning on using a pair of formula car rads and oil coolers to keep the temps down. Until you have developed a solid cooling plan you do not have a useful aircraft.
 

dwalker

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. FWIW, I prefer the Renesis engine core to the older 13B, because it's a bit lighter and designed for more output in the car (through higher rpm operation). It's also more recent production, and finding a core engine that's in good condition should be a bit easier. The Renesis is a bit easier to set up, as well. The 13B intake *and* exhaust are both critical for making real power, but the Renesis is relatively immune to exhaust tuning. It just needs a free flowing, minimal backpressure system. So tuning is limited to intake design (not that that is simple).



Charlie
The Renny in stock-ish form is less responsive to intake and exhaust modifications because the engineers at Mazda did an exceptional job with the variable length intake/6th ports and the stock exhaust. That said, the renessis responds even more like a 2-stroke than other 13Bs and exhaust is critical to making power. The Renesis exhaust ports are tiny compared to the intake ports and cannot be "ported" for higher flow without ricking breaking into the waterjacket or thinning out the wall so that it cracks in use. What does work is a tuned "dirt bike" expansion chamber style exhaust. Pictured is the exhaust from my PWC car, you can clearly see the expansion chamber, which greatly adds power under the curve.
Granted, there is no room in most airframes for such an exhaust, but it is important and could be developed.
 

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rv7charlie

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That's an interesting data point. IIRC, when the Renesis 1st hit the market, the two big rotary-focused speed shops in the US said that the best improvement they could see with any exhaust change they tried was about 7 HP over the stock exhaust manifold. I think they attributed the slight gain to reduced back pressure, and the lack of bigger gains to the fact that there's no intake/exhaust 'overlap' in the Renesis, so there's no interaction between exhaust & intake to move fresh intake gasses into the chamber. That was obviously a long time ago, and I haven't followed any of the research since that time.

How much gain were you getting from the custom exhaust? Did you modify the intake porting in some fashion to allow timing overlap?

Thanks for sharing your experience. The body of knowledge on rotary tuning (especially the Renesis) is somewhat limited compared to traditional piston engine tuning.
 

dwalker

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We saw 224whp on a stock "keg" with the following:

Racing Beat "race" ecu flash
Custom (we made them) alternator and water pump pulleys
Tuned air intake- we basically sat on the dyno and lengthened/ shortened/ tried various diameters and transitions- the intake tube and air filter
The expansion chamber exhaust.

Using the usual intake and header arrangements in general will see about 195whp.
 

dwalker

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I just re-read my reply and it leaves a lot out.

When we decided to race the RX8 in pro racing we picked it because it had been developed for US racing by Racing Beat and Speedsource with direct input and access with Mazda. I spoke to Jim Medere (miss that guy) at length about what they had found on the dyno while developing the format and what, if anything, I could do to improve on it. Specifically, I was intent on going to a racing ECU, the AEM Infinity, Bosch Motorsports, and MoTeC already having solutions to run the Renesis. I directly asked him if they had "left anything on the table" with thier ECU flash that I might get with a race ecu, and if the rules allowed where he thought there was power to be made. He literally snorted and told me point blank that if I got 5hp over what the race flash would make he would be shocked and pay me to tell him how I did it. He told me that in the Grand AM format the power was limited by the intake and exhaust rules and if I spent some time to develop it out that the tuned exhaust- specifically because it is a zero overlap engine- along with the intake length, then there was improvements to be had there.
So i built up a bunch of identical motors- all stock- and spent a few months dynoing and testing and melting down engines to figure out what worked, what did not, what caused failure, what those failures were and why.
The conclusions I came to mirror exactly what Jim told me-

Beyond a "light street port" to clean up the intake and very slightly adjust the intake timing and polishing the exhaust port there is little to be gained with porting the Renny. If you remove much (and with some plates ANY) material from the exhaust ports you will reduce the lifespan of the engine by introducing a failure point. The coolant jacket wall there is already thin, and grinding on it makes it thinner and it will fail at some point. When we cleaned up the exhaust ports we used the machine shops ultrasonic to determine wall thickness before even getting the grinder out.

The valving in the intake manifold and the 6th ports as set up by Mazda is fantastic. I messed with the opening/closing points, removed them, sealed them, etc. etc. and never did anything but make the engine less awesome.

Now for the heresy-
The Renesis hated to be run rich. We often had dyno operators stop the runs (we were often dynoed post-race) because their wideband would show impossibly lean. Part of this was due to the tuned exhaust and its scavenging effect, but it was also due to the Renesis not liking to be run stink rich. The tailpipe when we ran 100UL Sunoco (mandated fuel) was always the proper crisp white/grey that a race cars exhaust tip should be.
We consistently made best power on 91 octane. We made slightly less on the mandated 100UL.
We consistently made best power at 210-215deg as measured by the AIM dash reading a calibrated sensor. It will live a very long time at 215deg. It will live a much shorter time at 230deg. At 230deg we noted a consistent tapering off of power. Below 205 deg the engine makes less power throughout the curve. At 180 degrees it not only makes less power, carbon becomes an issue.
We ran the stock MOP WITHOUT a Sohn adapter.
Racing Beat documented premixing with a quality two-stroke oil such as Redline/Silkolene added power throughout the curve (about 7hp), and my experience mirrors this.
We ran the engines between 5000-10000 rpm. Most shifts were at 9400rpm. Data showed that the only reason to go to 10000 rpm was if you just had to hold that gear a bit longer.

When I would tear down the engines after a season of racing- about 100 or so hours, depending on test days, dynoing, and actual racing- the engines would look brand new inside, with little to no carbon fouling and often zero measurable wear. I attribute this to the high-RPM operation, good fuel, good premix, and running the engine within the proper operating temperature range.

We experienced three engine failures over the 4 years we ran the cars.
The first was most likely due to old age or prior damage, as it was an 80K mile "keg" obtained from a salvage car. It lost power and started to spew smoke on the last lap at Mosport. The driver radioed in, said he had engine trouble, and I directed him to finish the race. He finished 4th, as I recall.
The second was at Mid-Ohio when we were held at pit-out while the field made the reconnaissance lap prior to the start, as we had battery issues and had to push-start the car on pre-grid. With no cooling fan and having been held on grid at idle for an extended length of time, the car started to overheat at pit out. The temperature hit 260degrees before the driver made the call to shut the car off. That engine was a write off.
The third engine failure was immediately following Mid-Ohio, as we had no time (less than two weeks between races ) between Mid-Ohio and Sears Point, and bought an engine from a former competitor that was represented as brand new, best of everything, pro-built.. it lasted 20 minutes in the car before shelling the bearings and sending material throughout the oiling system while at Sears Point. This required overnighting in all the parts to build an engine and a complete oil cooler system, "stealing" an engine from a Pro-Formula Mazda team, tearing it down for parts (the Pro FM engines are S2, we used the S1 engine) and building an engine in the paddock of turn 7 at Sears Point in front of a crowd. To my knowledge that engine is still running today, as I sold it to a customer when I stopped racing the RX8.
None of the failure modes of the engine stopped the engine from running, it simply lost power.

I am sure there are things I am leaving out, feel free to ask anything to clarify or expand.
 

thjakits

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As much as I love the rotary engine (...is there anything sweeter than the 4-rotor dyno run?) - I followed a load of rotary builds when PL was still around (rv7charlie knows them all...) - there was trouble ALWAYS! Some more some less - but most installations were a somewhat lengthy evolution to get to the point where the builder was happy in most respects...
You are building a "pickup with a built suspension and drivetrain" to do "offroad" flying - personally I would leave a rotary installion for a case where you want speed and enjoy the "r&d&t" more than the flying....

I would be looking at a direct-drive, turbo V8 or V6 or a multi-V-belt redrive (study up on the Robinson helicopter, you can download EVERYTHING from their website for free - spareparts catalog, maintenance and overhaul manual, etc...).
As I was educated about in a different thread - Subaru 4 and 6 cylinder engines are excellent too, these days!

Why a V-belt redrive - because I have 6k+ hours flying with v-belt redrives without a single incident!
Robinson DID have issues with the original Gates belts, but since they switched to Mitsuboshi belts they run about perfect.
[Yes - MitsubOshi...]
In a prop application you probably don't need a complex "clutch engage" system - just a proper tension-system, I can imagine a springloaded only upper sheave ....
Advantages of a Robinson inspired belt system:
- drivetrain easy to inspect, basically on every pre-flight
- no lubrication - unless you want to separately lubricate the beltdrive bearings
- gear"box" can be a lightweight, but still stiff triangulated design

Sometimes one just has to let go of the tech at your heart!

Though the rotary is actually simpler than the other car engines in principle, the devil is in the details...
There is just so much more aftermarket and collective knowledge out there for the regular piston engine than for the rotary. Then - most if not all rotary development is going towards sport and racing, not "pickup and load hauling"....

In my opinion, you are a better off with a piston - either car derived or a BIG old Lycoming or Continental - de-tune like Robinson did (on paper only...) and you should enjoy 2000-2200 hrs of troublefree service (if you can find a decently priced one - even a total runout costs a fortune these days...)
[Though, lately Lycoming has an issue with the engines not lasting at all...}


'nough said....

Cheers,

thjakits
 
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FinnFlyer

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... The only issue that Tracy's box had was the input shaft thrust bearing was a 'stack' of roller bearings with a 1 mm washer between them (best he could do when he designed it, to get both thrust load and rpm ratings high enough. There are now single row bearings that are near-dropin replacements for the original double stack.
...
Note that the one-bearing replacement is only rated for 6,000 to 6,500 RPM.
Doesn't mean that it'll disintegrate if you run it above 6,500 RPM, but that its lifetime will drop.
So if you routinely and consistently will be running above 6,500 RPM then check the bearing every 250 or so hours. (llook up the bearing lifetime vs RPM specs).

Be patient. Tracy sold a lot of the RD-1C (2.85:1) drives. They are out there and definitely not all flying.

As for engine controller, Tracy recommends the SpeedUino, using TunerStudio.
However, if you have some electronics and programming background, Tracy's EC3 is hard to beat for a compact dual (redundant) controller in one box.
I have one in the RV-4 and just love the auto-tuning feature: set the desired Air/Fuel (mixture) point and just fly.

Finn
 

rv7charlie

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To what do you attribute the gains from the exhaust? Was the exhaust tuning actually pulling a vacuum on the combustion chamber as the port closed, and was that what helped with chamber filling on the subsequent intake?

Given the mild street porting of the intake, the pipe/airbox retune, and the controller remapping, in addition to the exhaust system, would you think that the early findings of ~7HP gain from just the header to be a reasonable estimate? I know they all interact, but do you have any idea where you'd have been in HP with the other changes in place & a manifold closer to 'stock'?

The info on temps is really interesting, though I'm not too surprised. A former racer on another list who ran the older 13B says he made best power at 160 degrees. I could never wrap my head around that, since the one Achilles heal for the rotary is that it loses so much heat energy to the 'swept' combustion chamber. Keeping temps low always sounded like it would make things worse.

The data on octane aligns with other experiences I've read about. I wonder how much of the HP gain with oil premix is due to friction reduction (since ther'e'd be oil injection otherwise), and how much is due to lowering the octane another notch. Was the HP gain from adding premix in addition to the metering pump, or in place of the metering pump? Some of the aviation guys run a mod to the metering pump so it draws from a 2stroke oil tank instead of the crankcase.

thjakits, That's apples & pomegranates. I'd love to do an LS motor in something if I live long enough, but I'd never rape a 2 seat RV airframe with that much anchorage. The powerplant needs to fit the airframe (actually, the airframe needs to fit the powerplant, but the airframe is harder to change). And it's a lot easier to make a belt survive at 3000 rpm input than 7500 rpm input.

Finn,
When Bobby & Steve developed the single race bearing replacement, I tried to get them to look at balls instead of rollers. According to Monty, there are some deep race ball bearings available now that would fit that wouldn't even notice the rpm or axial load.
(Sorry for the random names; the mod developers are guys who have *lots* of hours flying behind Tracy's gearbox.)
 

dwalker

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To what do you attribute the gains from the exhaust? Was the exhaust tuning actually pulling a vacuum on the combustion chamber as the port closed, and was that what helped with chamber filling on the subsequent intake?
The way I think it works- While I helped the development it was an engineer in Indianapolis that did the original theory and development- is more along the lines of using the pressure drop from the temperature drop as the exhaust gas expands into the chamber works to increase scavenging effect and thus improve the exhaust flow from the ports. I also feel the long runner length smooths out the exhaust impulses, which combine to make the exhaust port more effective without its actually being enlarged.

Given the mild street porting of the intake, the pipe/airbox retune, and the controller remapping, in addition to the exhaust system, would you think that the early findings of ~7HP gain from just the header to be a reasonable estimate? I know they all interact, but do you have any idea where you'd have been in HP with the other changes in place & a manifold closer to 'stock'?
We never raced on a street ported engine. I tested a variety of ports but the data was erratic and there was a lot of evidence they shortened the engine life remarkedly.
I think that with an AEM/Mazdaspeed intake, any off the shelf header, a reasonably open exhaust, and the RB "Race" Flash you should see about 195-ish whp. Now, I have zero faith in ANY Cobb AP tune, beyond I 100% believe it will have an early death. The Cobb works great on many platforms, but the Renny ecu is not one of them. I am not sure what Jim did in the RB "flash", but I know he had direct access to the engineers that wrote the cal files and no real budget to figure it out. Unfortunately, it seems the ECU flash program died with Jim and RB no longer offers it.

The info on temps is really interesting, though I'm not too surprised. A former racer on another list who ran the older 13B says he made best power at 160 degrees. I could never wrap my head around that, since the one Achilles heal for the rotary is that it loses so much heat energy to the 'swept' combustion chamber. Keeping temps low always sounded like it would make things worse.
I would find it amazingly interesting to see a dyno chart where a rotary of any generation made more power at a lower coolant temp.

The data on octane aligns with other experiences I've read about. I wonder how much of the HP gain with oil premix is due to friction reduction (since ther'e'd be oil injection otherwise), and how much is due to lowering the octane another notch. Was the HP gain from adding premix in addition to the metering pump, or in place of the metering pump? Some of the aviation guys run a mod to the metering pump so it draws from a 2stroke oil tank instead of the crankcase.
RB maintained the additional two stroke in the fuel helped to improve the sealing between the side and corner seals tus improving compression a little bit. I very seriously doubt it had anything to do with friction reduction. The MOP (metering oil pump) is retained on all rotaries I build, the premix is in addition to that injected oil.
 

Vigilant1

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The MOP (metering oil pump) is retained on all rotaries I build, the premix is in addition to that injected oil.
Some of the aviation guys run a mod to the metering pump so it draws from a 2stroke oil tank instead of the crankcase.
How common is it to retain the metering oil pump in 13b/Renesis converted to aviation use? I was under the impression (from Tracey's conversion book and other readings) that most flying Mazdas are using premix only, primarily for enhanced reliability (..."one less thing....") and the advantages of burning 2 stroke oil rather than oil designed for a crankcase.
 

dwalker

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How common is it to retain the metering oil pump in 13b/Renesis converted to aviation use? I was under the impression (from Tracey's conversion book and other readings) that most flying Mazdas are using premix only, primarily for enhanced reliability (..."one less thing....") and the advantages of burning 2 stroke oil rather than oil designed for a crankcase.
To answer that we have to look to legend, back when we went from it being fairly "normal" for the mechanical OMP on the early cars to be rebuilt and no one thought anything of it. Then came the electronic OMP of the S5 FC RX7 and the S6-up FD RX7. The FC ecu would put the car into limp mode when the OMP "failed", which often times it had not failed, but had a wiring issue that put the car into limp mode. The answer "back in the day" was to simply block it off and go pre-mix.
That was and is wrong. No reputable rotary engine builder or tuner will tell you these days to remove the OMP. They do work, and they do not require input by the end user. What introduces a failure point is expecting people who often cannot maintain proper tire pressures to remember to add the proper amount of two-stroke oil to thier gas at fillups.
I used to modify OMP's for external feed to a tank full of two-stroke. That was wrong too. Once again this introduces another step that can be forgotten, and an additional point can leak, and can fail. The idea was "motor oil is not designed to burn", which is hogwash. All engines burn oil. The idea is "it will be a cleaner source of oil, engine oil is dirty, why would you want that injected into your engine? Hogwash in several aspects- first if your engine oil is "dirty" enough for it not to be injected into the engine, then you are an idiot for not changing it already. Second, removing a cap underhood every time you add fuel to the car introduces the very real potential for dirt and contaminants to find thier way into your oil injection system.An UNFILTERED system. Which is not smart.

The Renesis changed the nomenclature from OMP to MOP, and uses a pretty sophisticated version of the same OMP as used on the S5 FC and S6-up FD RX7's. I have as yet seen one fail. I have seen them damaged upon engine removal by oafs, I have seen them melted by "cutting edge" turbo systems, and I have seen them pulled off for no reason at all, but I have yet to see one fail.

Mazda as a company is pretty smart, so in this instance I leave thier very well developed and tested system alone.
 
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