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    RE: <span class= - 12/19/2003 1:46:41 AM   
    Herby 1


     

    Posts: 10
    Joined: 4/26/2003
    From: Northern Arizona
    Status: offline     		My G62 runs about 400 rpm slower here at 6800 feet than it does in Phoenix, about 1000 feet..The G26s run about the same....

    (in reply to dick Hanson)
           Post #: 51

    RE: <span class= - 12/19/2003 10:05:23 PM   
    pe reivers



    Posts: 3015
    Joined: 1/23/2002
    From: Arcen, , NETHERLANDS
    Status: offline     		So I took out my old books. The smell of the pages reminded me I'm not getting any younger either
    So it all comes together now is a few kiss priciple calculations.

    Data: power (N) correction for IC engine power curves is linear with barometric pressure (N1/N2=P1/P2 *C) {C is a constant to correct for different units that may be used}.
    Data: Blade lift (thrust) is linear with barometric pressure, whilst lift has fixed relationship to foil drag at same AoA (lift=C*density*Vsquare*liftfactor*A)
    ergo conclusio: engine torque reduction versus power reduction with barometric pressure reduction remains balanced.

    It seems that there is a perfect balance between prop load and engine torque, regardless of barometric pressure, as observed by RCign, and any rpm differences may lead to conclusions other than that, i.e. engine breathing efficiency changes, and power curve shift due to thinner/thicker air, or a slight prop mismatch to the engine (static, not necessarily in flight). Observed thrust falls off the cliff up there.
    It is very convenient that this happens like it does. This way we can compare prop rpm all over the globe, and not worry about altitude

    Electrics bonus:
    In thin air your model needs to fly faster in order to support it's weight. Lift is related to speed squared. After some juggling, this results in (V2=V1*(sqrt(P1/P2))), so instead of increasing diameter for more thrust, you need to increase pitch for more flight speed.

    It is always very reassuring to find observation in line with theory.

    _____________________________

    Pe, Dealer for MVVS, MTW and Mejzlik; www.mvvs.nl
    There is sanctuary in analisys.

    (in reply to Herby 1)
           Post #: 52

    RE: <span class= - 12/20/2003 12:18:51 AM   
    dick Hanson



    Posts: 10192
    Joined: 12/12/2001
    From: slc, UT, USA
    Status: offline     		yes - tho a real factor which upsets the power/ and prop relationship --is internal engine friction losses --which are constant .
    easy to ignore -but very real

    _____________________________

    I am watching you
    Libby

    (in reply to pe reivers)
           Post #: 53

    RE: <span class= - 12/23/2003 12:08:12 AM   
    pe reivers



    Posts: 3015
    Joined: 1/23/2002
    From: Arcen, , NETHERLANDS
    Status: offline     		OOPS,
    I re-read the thread, and saw I reported 41 lbs static from the Menz 22x10 prop at 7450 rpm. Please correct that figure to 31 lbs. A mighty obnoxia of the brain made me miss the typo. Shame on me

    For the 24x12 Menz-S prop the Krumscheid pipe in my setup seemed to be too short. A bit hard to tune, and only (?) 6150 rpm at 27 lbs static. The exhaust header gets quite hot, and that makes the coupler slip off the header. It feels as though the pipe flow is restrictive to the engine, and internal pressure in the pipe is too high due to the small 14mm stinger. I must add an inch or so, and see how it reacts, and if the exhaust pulse pressure waves can counteract the internal pressure of the pipe.

    Did any of you experiment with horn shaped pipes, loong straight belly and reflector baffle instead of reflector cone?? I am still fiddling around different pipe dimensions in order to get a good starting point for cutting metal.
    My current aim is a header of at least one inch diameter, preferrably 1 1/8", and 11/16" stinger, 5-7-9 degree diverging cone, with a 60mm belly and pipe volume a minimum 2 pints to make op the length balance.

    _____________________________

    Pe, Dealer for MVVS, MTW and Mejzlik; www.mvvs.nl
    There is sanctuary in analisys.

    (in reply to dick Hanson)
           Post #: 54

    RE: <span class= - 12/26/2003 7:04:48 AM   
    3DFanatic


     

    Posts: 2669
    Joined: 7/22/2003
    From: Tacoma, WA, USA
    Status: offline     		Yeeee haww. Sounds like the perfect engine for the 84" Edge I'm gonna get

    _____________________________

    -Aaron
    3Dfoamy.com

    (in reply to pe reivers)
           Post #: 55

    RE: <span class= - 12/26/2003 8:53:24 AM   
    Mike Bogh



    Posts: 2466
    Joined: 12/7/2001
    From: MT Vernon, WA, USA
    Status: offline     		Greetings,

    I'll tell you one thing for certain.
    If Morris hobbies is involved in any way, and Robert is the first and last authority on service, then you couldn't give me a MVVS, ever...not even for free.
    Does anyone of you think that you'll never need service on your gasser? Of course not.
    So here it is, all the hype and horsepower in the world won't get me into a position to have to deal with Morris/Robert ever. His reputation is just worthless from a customer service point of view.
    I have read and done research for the last month on every 50CC class engine available.
    There are excellent engines out there. ZDZ, Brison, BME, DA, MVVS, 3W, Zenoa....so what/who is the deciding factor all things being relatively equal?
    Price vs Power vs parts availability vs SERVICE reputation. Each engine has it's pros and issues somewhat.
    The one constant, unarguable, true fact is that Desert Aircraft has the absolute best customer service team out there.
    Not an opinion but documented fact.
    Having been in the Hobby for several years, I know first hand what service after the sale means. Companies like Horizon Hobby get it. So does Kange. Hobbico gets it. (arguably but their the biggest, OK?) DA absurdly gets it.
    Who gets my $$$?
    The company that takes care of it's customers. I will sacrifice some performance for excellent service. I will pay more to get excellent service. I will shout it from the rooftops and be loyal like a dog for excellent service.
    Same for bad service, I'll state that, too.
    I ordered a DA-50 the other day and you know what struck me as odd? They treated me like I was the only customer they ever had. I didn't kiss their arse, asked 20 questions and still they were eager to answer more. (Try that at Tower)
    I have never owned a gasser before so you can imagine my apprehension, and that didn't matter either.
    I got their service reputation right here on RCU, from all you guys.
    Bottom line, when Horizon or DA sells and services the MVVS line of engines, count me in.
    Until then no thanks, I'll pass thankyouverymuch.


    _____________________________

    Best to you all,
    Mike
    In memorium
    Art Grabow Sr. AKA Grnbrt..RIP mah Brother

    (in reply to 3DFanatic)
           Post #: 56

    RE: <span class= - 12/26/2003 11:02:14 AM   
    pe reivers



    Posts: 3015
    Joined: 1/23/2002
    From: Arcen, , NETHERLANDS
    Status: offline
    quote:

    ORIGINAL: BackAfter30

    Greetings,

    I'll tell you one thing for certain.
    If Morris hobbies is involved in any way, and Robert is the first and last authority on service, then you couldn't give me a MVVS, ever...not even for free.
    Does anyone of you think that you'll never need service on your gasser? Of course not.
    So here it is, all the hype and horsepower in the world won't get me into a position to have to deal with Morris/Robert ever. His reputation is just worthless from a customer service point of view.

    <Main body snipped out>

    Bottom line, when Horizon or DA sells and services the MVVS line of engines, count me in.
    Until then no thanks, I'll pass thankyouverymuch.



    As a free world citizen, you do not have to buy at Morris you know. You can get your engine from any place in the world that has a good reputation for serving their customers. Dealers outside the USA borders are out of reach of Morris's long arms.

    _____________________________

    Pe, Dealer for MVVS, MTW and Mejzlik; www.mvvs.nl
    There is sanctuary in analisys.

    (in reply to Mike Bogh)
           Post #: 57

    RE: <span class= - 12/26/2003 10:23:47 PM   
    David_Moen



    Posts: 1405
    Joined: 10/5/2002
    From: Salmon ArmBritish Columbia, CANADA
    Status: offline     		It's too bad the American distributor has muddied the reputation of these fine engines. But as Pe states, they are certainly not the only game in town. MVVS engines can be ordered from at least three other sources, Pe, myself, and Just Engines.

    (in reply to pe reivers)
           Post #: 58

    RE: <span class= - 12/27/2003 1:21:34 AM   
    JohnnyJ


     

    Posts: 298
    Joined: 1/26/2002
    From: Ponoka, AB,
    Status: offline     		Triad Aviation Ltd. in Alberta, Canada will be selling them too!
    1-888-783-3912
    Great service from them too.

    John

    (in reply to David_Moen)
           Post #: 59

    RE: <span class= - 12/29/2003 1:39:36 AM   
    DKjens



    Posts: 2087
    Joined: 2/10/2002
    From: Pasadena, CA, USA
    Status: offline     		Well, I have my mvvs58i with header and larger 2.75" x 14" JMB can installed in my Wild Hare 28%Edge540T, and the plane is ready for maiden flight tomorrow, Monday Dec. 29. I have a ZingerPro24x10 prop on the engine for now, and I ran it for a few minutes today for a preliminary check of set up and possible glitching. This set up is very quiet, and the exhaust has a great metallic ting ting sound to it. The engine turns this 24x10 prop like nothing. The tips sing/bark at 1/3 throttle, but I did not have a throttle curve programmed in yet. The engine primed very quickly (flips) and started very soon there after. High end seemed fine and so did low end. I set it to a low idle (1200-1500) while I went looking for my tach. It sat there and idled for 2-4 minutes while I searched, to no avail. When I came back, it took the throttle without a hick up or gurgle, I am quite impressed with this engine so far. The way it swung that 24x10 prop I will not be surprised if this engine DOES have the same or better power than the zdz80rv.
    Here are a few pictures of my set up, please ignore the messy work table he he.
    DKjens

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    (in reply to JohnnyJ)
           Post #: 60

    RE: <span class= - 12/29/2003 11:53:36 PM   
    Kevin Greene



    Posts: 2675
    Joined: 3/28/2002
    From: Jackson, TN, USA
    Status: offline     		DKjens,

    Weeeeeeellllll??????? How'd the maiden go?!?!?!?!? Don't leave out any details!!!!

    Kevin

    (in reply to DKjens)
           Post #: 61

    RE: <span class= - 12/30/2003 2:13:26 AM   
    DKjens



    Posts: 2087
    Joined: 2/10/2002
    From: Pasadena, CA, USA
    Status: offline     		Maiden went very well. I just flew the plane for about 5 minutes on forst flight, since engine acted a little lean. The engine yanks the plane around like a ragdoll, continious uplines at 1/3 throttle or so. I richened up the low end 1/8 turn and top end 1/4 turn and engine ran much better. This engine is very responsive, no gurgling or funny things, I really like the engine, and my muffler setup is not only very quiet, it also sounds great. I really like this plane too, so can it get much better? The CG is at 5.25" behind LE, which make is slightly tail heavy, just enough to pitch up at sloow speed, but not tail heavy enough for my taste. I just flew it around some, big loops, snaps are great, and the plane stops fast. When it stalls, you have to be a complete idiot not to expect it, and it doesn't snap violently at all. I did a couple of elevators with minor wing rock, hovering needed continious up elevator. High alpha knife right to left (canopy towards me) had little tucking to gear, the other way needed a little more work. I felt very confident when flying this plane, felt I could always pull out of stuff in time, was never afraid it would unexpectetly snap on me, and it does slow down to a crawl on landings - it is most definetely a keeper, thank you Tom, again.
    Here's a picture of my inside fuse set up, notice the upside down rudder servo he he.
    DKjens

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    (in reply to Kevin Greene)
           Post #: 62

    RE: <span class= - 12/30/2003 2:38:00 AM   
    Kevin Greene



    Posts: 2675
    Joined: 3/28/2002
    From: Jackson, TN, USA
    Status: offline     		DKjens,

    Sounds good!!!


    Did you ever figure out what caused the interference on your other plane????

    Kevin

    (in reply to DKjens)
           Post #: 63

    RE: <span class= - 12/30/2003 2:45:51 AM   
    DKjens



    Posts: 2087
    Joined: 2/10/2002
    From: Pasadena, CA, USA
    Status: offline     		Kevin,
    Nope, never did figure it out. However, something much like it happened to a friend and his Half-Time/Brison3.2 at my regular field this past weekend, or the weekend before, I was just told today. He asked me today if I had sent the Rx an for a check up, and if I had gotten any info, which I have not, and I have not. He also flyes JR and used a 645 receiver, and it went into fail safe, and that was the end of that plane. On my Edge I have fail safe set at engine idle, all surfaces neutral and a little left rudder, as if that will save the plane in case of a continious lock out. I am getting another, and third, DiablotinXL beginning of next week, but this Edge sure is a fine plane. I just saw Milton's video of his Edge flying, and boy is that loud compared to mine. Often I couldn't even hear mine in the air, and we had no wind at all, I had to wait for a angle to hear mine he he.
    DKjens

    (in reply to Kevin Greene)
           Post #: 64

    RE: <span class= - 12/30/2003 2:47:10 AM   
    Kevin Greene