"Micromaster"-- Centerline twin using small industrial engines

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Vigilant1, Nov 13, 2018.

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  1. Mar 26, 2019 #721

    blane.c

    blane.c

    blane.c

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    When I look at the engine crankshaft from the pulley side I see a small protrusion of greater diameter extending from the crankcase seal.

    B&S 810 CRANKSHAFT END CLOSEUP.PNG B&S 810 CRANKSHAFT LONG.PNG

    You can see the groove towards the end of the crankshaft on the left hand end in the second image. This groove is approximately were the oil seal is. I would investigate the idea of a "beefy cup" area of a propeller extension that would be a press fit over that protrusion and not interfere with the seal. From an engineering standpoint would it be sufficient in transferring the stresses to the bigger diameter or just a decoration?
     
  2. Mar 26, 2019 #722

    Vigilant1

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    Just between you and I, the speed with which Fritz is pushing that project ahead is borderline alarming. Why, in the time we've been yacking about this one issue (engines), Fritz has built the CAD files for a complete fuselage, made a mock up, and has a couple of groupies already cutting materials. No--the Micromaster will NOT be rushed to first flight in this way! ;)
     
  3. May 18, 2019 #723

    blane.c

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    Any progress update's on the Micromaster?
     
  4. May 22, 2019 #724

    Vigilant1

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    No, nothing significant. Little things:
    - I have written a letter to Mel Asberry (he writes the "Ask the DAR" column in Kitplanes) about the Operating Limitations of a plane like the Micromaster--and how a designer/bulder of such a plane can know if he'll be allowed to fly it without thousands of dollars worth of additional and ongoing instruction.

    I wrote:
    The MicroMaster project becomes a lot less appealing to me if I have to spend $5K to get an MEL, and stay current (rent a twin for every BFR?) just to buzz around in this little plane. Anyway, we'll see if Mr Asberry thinks the question is worthy of attention. His column in Kitplanes is well written and useful, but this is a question that is a bit off the beaten path.

    - I struggled a bit with some drawings. I probably need to get some help to identify software that is worth learning. I wasted a lot of time, I dang sure am no Fritz. I coud have gotten better results with graph paper and a ruler. Nothing worth sharing.

    - The several tables already in this thread (with estimated specs and performance estimates of various versions) have been de-formatted into oblivion by the transition to the new Xenforo forum software. I'm trying to find a way to make future tables that is at least as easy as what we used to have in the old software.

    - I'm following the ongoing thread on Vanguard/B&S aero engine conversion. As you noted previously, the Micromaster would be a pretty good mule for putting flying hours on these engines, provided it can fly (and climb) well on one of them. Every hour of flight time puts two hours on the engines, and we'd get to wring out both a tractor and a pusher configuration at the same time. Unless something changes from previous estimates, the MicroMaster would need at least 28 HP for safe single-engine climb. So, I'm focused on the Vanguard 810cc engine now because, as these industrial engines go:
    -- It has a good HP-per-dollar ratio.
    -- It has a good HP-per-pound ratio
    -- Folks are already flying them successfully in direct drive mode. There's even a kit supplier that is supporting them with conversion parts. So, apparently it can work.

    Any other updates from interested parties?
     
    Last edited: May 22, 2019
  5. May 22, 2019 #725

    BBerson

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    I think a multi engine solo endorsement is an option, instead of the rating.
    See the Operating Limitations for solo endorsements.
     
  6. May 22, 2019 #726

    pictsidhe

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    Decoration. Look for tapered the shaft version. That will also sort out the needed fit with the prop adaptor.

    Edit, crank drawings for the small block vanguard as I couldn't find one for the 810. Those are standard crank ends. At least one of tapers on the first page is also available on the 810s as well as some others. The rest of the crank is different, though.
     
    Last edited: May 22, 2019
  7. May 22, 2019 #727

    TFF

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    Once you have a multi, you do not have to “stay current” to fly yourself and it only takes three takeoffs and landings in your own plane to be legal to carry people every 90 days. Biannual does not have to be in anything special.
     
  8. May 22, 2019 #728

    Vigilant1

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    It's hard for me to tell. The boilerplate language often used for the Operating Limitations these days says:
    Well, anyone with a PPC/SEL meets that requirement.
    And the next line of boilerplate reads"


    Section 61.31 is all about type rating requirements, additional training, and authorization requirements. (e) is for complex airplanes, (f) is for high performance airplanes, (g) is pressurized airplanes, (h) is "additional type-specific training, (i) is tailwheel acft, and (j) is gliders. At the end of that section we have this which would seem to exclude E-AB aircraft from the requirements of § 61.31 (since they aren't type-certified):
    And to make it more clear:
    But, I'm pretty sure the DAR has quite a bit of discretion with regard to what is written in the OL's, and whoever operates the plane obviously has to follow those. I would imagine the natural inclination would be for the DAR to stipulate in the OL that any operator of this multiengine E-AB must have a multiengine rating or endorsement (to include multiengine, centerline thrust). But, I would think a DAR might also use this discretion to >not< require such a rating/endorsement, given the particular aircraft's attributes:
    --- Single seat
    --- Centerline thrust
    --- Safe single-engine climb at the MTOW listed on the OLs (maybe include a max density altitude?--seems unwarranted as even above this altitude the plane would be safer if one engine is lost than a single would be in a similar occurrence. Maybe stipulate "no single engine takeoffs" just as the FAA eventually required Cessna to do for the 336/337. This is one of those things you'd think you wouldn't need to tell an adult, much less a pilot, but apparently . . .)

    Thanks, good to know. Still, that up-front cost to get the rating, or even an endorsement, might cost more than this little mower-powered sky scooter.
     
    Last edited: May 22, 2019
  9. May 22, 2019 #729

    blane.c

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    How are you doing on endorsements? Most twins are high performance needs endorsement, most twins are complex needs endorsement, sometimes less expensive to take endorsement rides in a high performance complex single then multi ride is just for multi. Also Sierra Seaplanes " I think" has a regular land Apache that may be reasonable. Remember you just want a VFR rating? Most packages are for commercial pilots so include MEL instrument training for checkride. Doing engine out instrument approaches really ramps up the time for many.
     
  10. May 22, 2019 #730

    Vigilant1

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    How am I doing on endorsements? I'm doing great! The last one I got was for solo flight when I was a student, and that's the only one I need or want. My hope is that a plane like the Micromaster wouldn't require any endorsements or additional ratings, but we'll see about that. It's not high performance, it's not complex, it's single seat, it is experimental, and without a relevant Vmc or any need for fancy footwork or throttle adjustments to keep it upright in the event of an engine failure, the design is intended to avoid many of the peculiar vices of conventional twins--and singles.

    Another issue might be insurance. While hull insurance might not be a major concern for many folks on a low-cost, moderate-value homebuilt, lots of airports require any actively flown plane in one of their hangars or tiedowns to be covered by liability insurance. And, I'm guessing those insurers might require a multiengine rating or endorsement even inf the FAA doesn't.

    I think the Cri-Cri folks have covered some of this ground already. There aren't many in the US, and they aren't a true centerline thrust twin, but they are experimental, single seat, and the engine/slipstream/canopy geometry reportedly makes them fairly easy to handle one one engine.
     
    Last edited: May 23, 2019
  11. May 26, 2019 #731

    blane.c

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    I wonder about waiver or letter of authorization/or/deviation/or/demonstrated ability. You need special permission. It may be how Cri-Cri owners do it or they may of all had to go get a rating. Some of them may have satisfactorily demonstrated the ability to control the aircraft to the FAA or authorized inspector and have gotten some form of letter. A demonstration of ability can be witnessed from an inspector on the ground in communication with the pilot. A insurance company that routinely insures aircraft and pilots will likely recognize a letter from the FAA.
     
  12. May 26, 2019 #732

    Vigilant1

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    That's another avenue worth looking into, thanks. If the "permission" is included in the aircraft operating limitations (i.e. if they contain no stated requirement for a multiengine rating or endorsement), that would mean the permission is linked to the plane, not the pilot, and that would be most convenient down the road.
    If the LoA, deviation, demonstrated ability, etc is granted to the pilot (not the plane), then it's a bit more cumbersome later (but might still be a lot cheaper and just as conservative/safe as getting a MEL rating for this purpose.) For example, maybe the attributes of the plane could be documented for the FAA, then during the flight portion the FAA inspector could see the plane/pilot demonstrate a simulated engine failure on climbout (demonstrate it can be done on either engine), a single-engine go-around with reconfiguration, etc. Ideally it would be as simple as that, and ideally there's already a well established procedure for it (applicable to E-AB single seat acft), and the permission to operate is tied to the aircraft (with properly placarded procedures in the airplane/checklist) . I'm pretty sure it will be more involved than this ideal scenario.
     
  13. May 26, 2019 #733

    BBerson

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    But why do you want a rating? The purpose of a rating is to have the privilege of carrying a passenger.
    To fly solo doesn't require a rating.
    The FAA requires a LOA for jets, I think. I haven't heard what is required for a CriCri, if anything.
     
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  14. May 26, 2019 #734

    Vigilant1

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    Agreed, I don't want to get an MEL rating or an endorsement in order to fly a plane like the Micromaster (assuming it performs as we'd like: safe single-engine ROC on either engine, demonstrated min controllable airspeed < stall speed, etc). But (as I understand things) when writing the Operating Limitations, the DAR has significant discretion, and one "safe" thing to do is to require that anyone operating this multiengine plane have a multiengine rating or endorsement.

    Here's a question to the EAA and their answer, FWIW. It is about the Cri-Cri, but seems applicable:
    This was from a few years ago, so no Basic Med, etc.

    Before spending a lot of time with design or construction, it seems pretty important to find out if the DAR is likely to add the requirement for an MEL rating (or endorsement) in the Operating Limitations, and what factors would be important in his/her decision about this.
     
  15. May 26, 2019 #735

    blane.c

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    Looked up 61.31 there it is all the way down the whole stinking page at the very bottom. 61.31 EXCEPTIONS.png
     
  16. May 26, 2019 #736

    Vigilant1

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    Right. But anyone operating an aircraft must comply with the aircraft's operating limitations. And if the DAR puts a requirement for an MEL rating (or endorsement) in those OLs, then the pilot of the plane needs to have that rating (or endorsement) regardless of what Section 61.31(L)(2)(B) says. The EAA's answer to a related question about this sure makes it sound like a possibility. So, I'd sure like to know in advance if a DAR is going to do that, and what factors might affect that decision.
     
  17. May 26, 2019 #737

    blane.c

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    Obviously you need to know who your DAR is and more importantly what is their favorite Whiskey.
     
  18. May 26, 2019 #738

    BBerson

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    The EAA answer is insufficient. No mention of solo endorsements.
    FAR 61.109 (b) requires a person who applies for a private pilot certificate with a multiengine class rating must log 10 hours of solo flight.
    So obviously a person can log solo time without a rating.
    Is logging solo time prohibited in an EA-B such as an RV-12?
     
  19. May 26, 2019 #739

    blane.c

    blane.c

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    "61.31 (I) 2 The rating limitations of this section DO NOT APPLY TO - …………. (B) AN EXPERIMENTAL TICKET, UNLESS THE OPERATION INVOLVES CARRYING A PASSENGER;"

    DO NOT APPLY TO.

    So solo experimento no problemo'
     
  20. May 26, 2019 #740

    blane.c

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    I have been looking for that little phrase for months.

    It is for experimental pilots who are not multi engine rated and who fly solo and want multiple engines "the golden words"

    61.31 (I) 2 (B).
     

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