Mazda Rotary - what are the issues to be overcome?

Discussion in 'Mazda Rotary' started by RSD, Aug 30, 2019.

Help Support HomeBuiltAirplanes Forum by donating:

  1. Sep 4, 2019 #41

    kbd512

    kbd512

    kbd512

    Member

    Joined:
    Jun 27, 2016
    Messages:
    15
    Likes Received:
    3
    Location:
    Houston, TX
    If someone is serious about building an all-Aluminum engine, then it might be worth their while to speak to someone from Gamma Alloys. Anyone who thinks it'll be cheaper to design and manufacture this new engine than using the existing Continental or Lycoming engines is a bit more optimistic than I'll ever be, but I wish them all the best.
     
  2. Sep 4, 2019 #42

    Lendo

    Lendo

    Lendo

    Well-Known Member

    Joined:
    Feb 7, 2013
    Messages:
    315
    Likes Received:
    47
    Location:
    Brisbane
    RSD, Rotary is the way to go all right, requires some expertise and understanding of the motor. People that know them love their potential, however development of any engine is a costly exercise and the Rotary is no exception, see Powersport 178 lbs with super light housings, Mistral (love their engine and PSRU - bulletproof/ expensive), Tracy Crook developments.
    For power Peripheral porting is required. Side ports are restrictive.
    Cruise at 6,000 rpm, which is noting for the Rotary and is the lowest strain on the motor.
    Ceramic Apex seals.
    The latest technologies may make Superlight housings more readily available, at the moment though, the technology is still expensive.
    However we can still dream of the possibilities. All it takes is money, and lots of it! I'm hoping to win Lotto.
    George
     
  3. Sep 4, 2019 #43

    RSD

    RSD

    RSD

    Well-Known Member

    Joined:
    May 20, 2019
    Messages:
    179
    Likes Received:
    35
    A FADEC Lycoming or Continental with 350 hp is US$120,000 - I reckon we can build and develop a successful rotary for that - and gold plate it.
     
  4. Sep 4, 2019 #44

    Lendo

    Lendo

    Lendo

    Well-Known Member

    Joined:
    Feb 7, 2013
    Messages:
    315
    Likes Received:
    47
    Location:
    Brisbane
    RSD,
    For sure much cheaper than, are you someone who works with engines? do you know the rotary well?

    You will need a good PSRU, there is a chap on here that is developing one, he's a Mechanical Engineer and knows his stuff - forget his moniker (maybe RSV4) but he's laid up at the moment after surgery on his shoulder, maybe he will chime in - if he can type!

    Remember for power the engine needs Peripheral Ports. These have been known to leak coolant if not done well. There has been a number of methods tried some better than others - do your research as I can't say which is better long term.

    Let us know what your skills levels are or what access you have to those skills levels needed.
    If you use the Cast Iron (standard) housing you won't get away with much less than 350 lbs for a firewall forward 2 rotor Rotary with PSRU. Perhaps those who are using one currently can chime in and give a better estimate.

    I wish you well, as I love this engine as it has enormous potential !

    I even found a German made Diesel Rotary engine, (Aluminium housings) which already has Peripheral ports has 2, 3 and 4 rotor developments. It's not quite as big as the Mazda rotary, but has good German engineering behind it. I don't have the details to hand but I can get it to you if required, it could be expensive. From memory it is about 150 hp for the 2 rotor. The chap whose Company produces these engine has a Doctorate in Engineering, I assume from his moniker.
    George
     
  5. Sep 21, 2019 #45

    Lendo

    Lendo

    Lendo

    Well-Known Member

    Joined:
    Feb 7, 2013
    Messages:
    315
    Likes Received:
    47
    Location:
    Brisbane
    RSD,
    I'm in Brisbane if you want to sit down and chap about Rotaries There are considerations to implementing the Rotary as well I have contacts in regard to this that may be able to help you. There is nothing to developing the Mazda Rotary for Aviation that's insurmountable, all it is required is the right contacts, the right knowledge and depending on how far you wish to take the development, sufficient 'where with all' to meet the task.
    I had many discussions with Mistral, but didn't know they sent engines to Aust. for balancing, I would like to know who that is ?

    BTW after reading all the comments (this time) there are good comments/ reality checks/ suggestions form most on this subject.
    George (Brisbane 07 33515448)
     
  6. Sep 21, 2019 #46

    steve izett

    steve izett

    steve izett

    New Member

    Joined:
    Aug 12, 2019
    Messages:
    4
    Likes Received:
    3
    Hi Guys.
    I'm new to this forum.
    The best information I know for rotaries in aircraft is the flyrotary forum. <flyrotary@lancaironline.net>
    There are plenty of guys flying behind mazda rotaries. Most are RV's.
    Now that Tracy Crook (Real World Solutions) has retired his gearboxes and computers are no longer available.
    Having said that Neil Unger has produced a box and is selling them. He is in Parks. I can provide contacts if you require.
    People are now using various computers to power their fuel and spark.

    My aircraft is a recently completed (13 years in the process) Glasair Super II RG. It is powered by an RX8 4 port engine.
    I hope to fly our 4th flight under phase #1 tomorrow.
    P Porting does produce more horsepower, but you can produce a solid 180+hp with side ports @ 7000 rpm.
    OEM Apex seals are fine, ceramics are not required unless your turbocharging to higher boost levels.
    The FWF weight is pretty close to an equivalent IO360. My Glasair Weight and Balance is very similar.
    Happy to help if I can.

    Steve
    0403 194 505
    Aircraft based at Serpentine Aircraft Builders Club Perth WA
     

    Attached Files:

    Topaz and BJC like this.
  7. Sep 21, 2019 #47

    BJC

    BJC

    BJC

    Well-Known Member

    Joined:
    Oct 7, 2013
    Messages:
    9,501
    Likes Received:
    6,262
    Location:
    97FL, Florida, USA
    Welcome to HBA, and congratulations on your project.

    Wrt to weight and balance; what is the weight of your propeller, and is the battery on the firewall, in the baggage area, or somewhere else?

    Thanks,


    BJC
     
  8. Sep 21, 2019 #48

    rv7charlie

    rv7charlie

    rv7charlie

    Well-Known Member

    Joined:
    Nov 17, 2014
    Messages:
    412
    Likes Received:
    156
    Location:
    Jackson
    Hey Steve,

    So, going out on us over at Flyrotary, huh?

    Welcome aboard over here!

    Charlie (different email address over here)
     
  9. Sep 22, 2019 #49

    steve izett

    steve izett

    steve izett

    New Member

    Joined:
    Aug 12, 2019
    Messages:
    4
    Likes Received:
    3
    Hi there Charlie.
    It was one of you guys, maybe you, that put me onto this list.
    I saw the reference from Australia and thought I should say something being in Western Australia, but maybe it's all been said already.

    Hi BJC
    I'm not sure of my prop weight. It's an Airmaster Elect.
    A guess it might be:
    Hub ~12kg
    Spinner and Slip Rings ~1.5kg
    Blades ~2kg each
    Maybe 20Kg total

    I have a very heavy exhaust using the OEM header + muffler under the cowl ~ 15kg

    Battery's (2 x HC20's behind rear bulkhead - 15.2kg 3980mm aft of cowl joggle.

    Steve
     
    BJC likes this.
  10. Sep 22, 2019 #50

    Lendo

    Lendo

    Lendo

    Well-Known Member

    Joined:
    Feb 7, 2013
    Messages:
    315
    Likes Received:
    47
    Location:
    Brisbane
    Hello Steve,
    I visited the Serpentine Airstrip in 2007, while riding my motorbike around Australia, one of my Vietnam Veteran contacts (in Perth) had friends there and he took me there to show me around, all very interesting and friendly.

    Can you give me Neil Unger's contact and tell me what sort of PSRU he's producing?

    Got to tell our USA friends that Western Australia is, because of distance from the East Coast, sometimes independent in terms of these sorts of developments. I tend to think their a bit like New Zealand, close but at the same time remote and independent.
    George
     
  11. Sep 22, 2019 #51

    steve izett

    steve izett

    steve izett

    New Member

    Joined:
    Aug 12, 2019
    Messages:
    4
    Likes Received:
    3
    Hi George
    Neils contacts are‭ +61468 623 933‬
    12348ung@gmail.com
    Ratio is 3.17:1
    It's a newer version of Tracys RD drives so uses I believe the Ford planetary gears from an Auto Gearbox.
    I use Tracy's RD1C @ 2.85:1

    Steve
     
  12. Sep 22, 2019 #52

    Lendo

    Lendo

    Lendo

    Well-Known Member

    Joined:
    Feb 7, 2013
    Messages:
    315
    Likes Received:
    47
    Location:
    Brisbane
    Thanks Steve,
    I understand there is a bigger Ford Planetary gear set available but I think their all subject to Thrust issues. I believe I have that info in my notes somewhere.
    However I will contact Neil and get the 'full bottle' on his design.

    Now what about this engine balancer, who is he?
    George
     
  13. Sep 23, 2019 #53

    steve izett

    steve izett

    steve izett

    New Member

    Joined:
    Aug 12, 2019
    Messages:
    4
    Likes Received:
    3
    I have no idea about any engine balancing.
    Steve
     
  14. Sep 23, 2019 #54

    Lucrum

    Lucrum

    Lucrum

    Well-Known Member

    Joined:
    Jun 10, 2008
    Messages:
    956
    Likes Received:
    189
    Location:
    Canton, GA
    I spent over $16,000 on my 20B, before redesigning the air frame for a turbine engine.
     
  15. Sep 23, 2019 #55

    narfi

    narfi

    narfi

    Well-Known Member

    Joined:
    Feb 23, 2016
    Messages:
    720
    Likes Received:
    350
    Location:
    Alaska
    So 1/10th the price? Which side are you arguing?
    How far did you get with your 20b? What made you decide to go turbine?

    Rotary engines seem to be very polarizing. I am very interested in them but want to stay realistic as well and not buy any "hype".

    My thoughts with no hard research or plans yet is a 13b in a new scratch built zenith 750 super duty. That airframe is designed for the 205hp io375 and the designer calls for 150-230hp for any engine installed.

    Plan on giving myself 5-6 years for the project. I have 20yrs experience as an a&p/ia repairing and rebuilding sheetmetal surfaces on small Cessna and pipers, but have never scratch built from plans, nor have I worked with any automotive engines. My thought is the airframe is a good forgiving one for me to learn with.

    Then once done I can take what I learned with that engine and build a more powerful rotary a 4place 200kt+ coast to coast cruiser.

    I like the approach of learning simple(of course I realize that is relative) on a "learning project" then doing a more advanced project with that knowledge.

    I took the same approach with boat building and built a canoe with plans purchased from the same designer I am building my powerboat from. It let me learn his system and approach and his quirks in writing etc... in a cheaper less dangerous if screwed up final product.
     
  16. Sep 23, 2019 #56

    rv7charlie

    rv7charlie

    rv7charlie

    Well-Known Member

    Joined:
    Nov 17, 2014
    Messages:
    412
    Likes Received:
    156
    Location:
    Jackson
    In pure money terms, you obviously saved only 25% vs a Lyc. As long as you're talking about a runout core. ;-)

    For those who haven't seen Lyc prices lately, here's one (discounted) example, of a motor that's rated somewhere between 20 & 50 HP lower than an 20B. Note the term 'core value' and the dollar amount. If you don't have a rebuildable core to send them, add $21,600 to those prices.

    Now, having said that, I'd agree that saving money probably shouldn't be the primary reason to 'go alternative'. When you get down in the 100-200 hp range, a good financial case can be made for finding a high time a/c engine from someone you know and trust who's about to upgrade or spring for an overhaul. With smaller engines and the typical low number of hours per year a homebuilt flies, that's likely to be less expensive than rolling your own alternative engine. So it really comes down to what you want, and have the skills to accomplish. Having said *that*, there's a ~190 HP Mazda Renesis hanging on the motor mount of my RV-7 project.

    Charlie
     
  17. Sep 23, 2019 #57

    rv7charlie

    rv7charlie

    rv7charlie

    Well-Known Member

    Joined:
    Nov 17, 2014
    Messages:
    412
    Likes Received:
    156
    Location:
    Jackson
    Hey Narfi,

    If you're not yet on the Flyrotary list, I'd strongly recommend it for info from guys that are flying them.

    On your choice of 1st build, how much do you know about the 750 SD? As a hint to info accuracy of factory info, perusal of the performance data on the website is...illuminating. (hope the formatting survives.)

    Performance IO-375 (205hp)
    single:
    gross:
    Take-off Roll 115ft 115ft
    Landing Roll 150ft 150ft
    Cruise (75% Sea Level) 105mph 105mph
    Stall Speed 34mph 34mph
    Rate of Climb 1350fpm 1350fpm
    Range(standard miles) 400 miles 400 miles
    Endurance 3.8 hours 3.8 hours
    http://www.zenithair.net/introduction-ch-750-super-duty/

    Everybody's mission and choices will be a bit different, and I don't want to pretend I know what you want, but I know that I'd want to know what I was buying into prior to purchase. A guy in my EAA chapter built (and lost) what amounts to the prototype {{edit:801SD}}, if you want some info on it. You can PM or email me if you want to discuss further.

    Charlie
     
    Last edited: Sep 23, 2019
  18. Sep 23, 2019 #58

    narfi

    narfi

    narfi

    Well-Known Member

    Joined:
    Feb 23, 2016
    Messages:
    720
    Likes Received:
    350
    Location:
    Alaska
    I am always looking for more information to help me make informed decisions.
    What are you trying to point out here? the single/gross numbers all being the same is somewhat confusing.

    I will send you a private message.
     
  19. Sep 23, 2019 #59

    Lendo

    Lendo

    Lendo

    Well-Known Member

    Joined:
    Feb 7, 2013
    Messages:
    315
    Likes Received:
    47
    Location:
    Brisbane
    The best Power is important to some people, but the standard Mazda engine is ample for some, I would suspect 160 hp at 350 lbs. with RSRU. The Peripheral Ported (PP) engine, gives more Power because it breathes better 200+HP, they don't need 2" inlets as their only running 6,000 to 7,000 rpm (for Aviation use), 40 to 44 mm is sufficient as Inlet Velocity is important and greater Inlet Velocity has a greater ramming effect for best Volumetric Efficiency.

    The problem is sealing the PP, as the ports cut through the Rotor housing cooling channels, so sealing is very important. One of the reasons people don't use them. I believe that someone is designing them with O-rings, to accommodate the expansion and contraction. That would be a difficult job as there's not that much room to include O-rings.

    Getting weight down is also very important, it sure is to me. I don't know how the Mazda all Aluminium housings are standing up, only time will tell.

    It's 'horses for courses' personal choices that best suits your needs/Goal.

    Do your research before making a decision.
    George
     
  20. Sep 24, 2019 #60

    thjakits

    thjakits

    thjakits

    Member

    Joined:
    Jul 4, 2014
    Messages:
    6
    Likes Received:
    2
    Location:
    Panama, Rep. of Panama
    Hi all,
    ...wow - LOADS of info about the Rotary here!
    Years ago I followed Tracy along his developement quest and also followed Paul Lamar's newsletter and website...
    It seems, not much has happened though - people seem to have settled in on what Tracy and others developed at that time....


    - ROTARY:
    I wonder what happed to the "ceramic-coated side-housings" that were "coming soon"?
    I suppose a specifically built rotary, based on Mazda dimensions and parts should be possible - IF it is properly calculated:
    - Peripheral ports of the right dimension for the rpm (I suppose "sweetspot"-6000rpm)
    - dual computerized control - spark and fuel
    - in tank fuel lubrication - sensor controlled oil mixing
    - heavy turbo (to take the sonic pushment and act as a silencer)
    - extra oil and extra oil-cooling

    - PSRU: You might want to look into belts! Robinson Helicopters use them since 40 years now and they are TUFF!! I suppose at 300 hp you probably want 6 of the kind Robinson uses. In a prop application you won't need a "clutch" (jack screw tensioner to engage the transmission slowly - so just a regular slightly adjustable belt-tensioner should do...
    Belts don't always sound confidence inspiring, but they are seriously strong and abuse-tolerant....
    And more likely - near impervious to torque-reversals/vibration....

    - you already mentioned Mistral - are there any assets left, they might be interested in selling?
    - would you be interested in reviving Mistral??
    [Though an awesome development, I think they missed the chance to do a Peripheral port engine.....]

    - Good old LYCOMINGS and CONTINENTALS:
    - Do you need certified engines?? You are considering to use a Rotary development, so I assume "experimental" is good enough! ?
    - Why would you need the super expensive Factory electronics version?
    - A good core - a quality overhaul, possibly a heads-porting job (REDUCE intake and exhaust cross section - unless it is already at the right size...)
    - adapt an automotive computerized ignition system (keep dual spark)
    - adapt automotive fuel injection
    - cleaned up cylinder-cooling fins, precise ducting for cooling
    - tuned exhaust - into a single turbo or dual turbos
    [A good friend had a Lyc-720 with 2 turbos on a NXT, and had a video - pulling 50" for 2 seconds... - I am sure he did not have $120k in that engine. Also a 6-cylinder certainly would be cheaper too...]

    -OTHER CAR Engines:
    - There was the certified LEXUS V8 out there - about 350hp, but TBO only about 400 hrs or so..
    Which doesn't mean you can't go for it again! The Lexus V8 is an extremly cheap core out there and people are pulling incredible power from it! [Youtube, Ford Capri-Lexus V8, and you will find a grey Capri with a 900hp twin turbo V8... Obviously you will NOT pull 900 hp in the air, but the fact that these guys drive their drag-racer on the road to the race, says something about that motor - also the live-span of that engine is amazing, considering it's purpose. Properly built to the task, it should be able to pull 350 hp non-stop for ever - belt PSRU again....

    - Also, there was/is a Long-Ez out there with a (I think...) big block alu-V8 DIRECT DRIVE! Engine is naturally aspirated, has short stacks and is built to make peak power around 3500 rpm - with the prop built accordingly...
    [You could explore that approach with Electronic control everywhere and a turbo....] - after all a Lyc 520 is fairly "big block" too...
    [Did anyone ever hear about a purpose-built SLOW running rotary?? Would that be even possible? Slow meaning - prop- direct drive - which might not be enviable anyway - ... considering the torque-pulses]

    - PROPELLER:
    - you may have heared about Paul Lipps' Elippse-props. Especially if you stick to a fixed pitch, this certainly would be a worthwile system to persue! (....today you might even be able to build a "automatic pitch adjustment into the prop - rpm dependent) if you go 5 or 6 blade you might even get away with 3800-4000 rpm....


    Good Luck!!

    thjakits
     

Share This Page

arrow_white