Re-engining the Camel with a rotary Gnome | Page 4 | FerrariChat
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Re-engining the Camel with a rotary Gnome

Discussion in 'Aviation Chat' started by snj5, Feb 10, 2013.

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  1. snj5

    snj5 F1 World Champ

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    #76 snj5, Feb 2, 2014
    One of the things I am going to need to become adept (and comfortable) with is shutting the fuel off in a descent, then restarting the engine. There are many old carburation paradigms I am going to need to get around.
    Looking at some videos of current Gnomes, about 4 seconds is all they cut the ignition at a time, punctuated with 1 second ignition periods.
     
  2. tazandjan

    tazandjan Three Time F1 World Champ
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    #77 tazandjan, Feb 2, 2014
    Russ- You just have to keep reminding yourself there is no carburetor on a Gnome, just an injector, and the pump is running all the time she rotates. As long as that big prop is rotating, restarting is no problem. Guarantee nobody propping one can turn it that fast.
     
  3. Bob Parks

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    #78 Bob Parks, Feb 2, 2014
    This stuff is SO interesting. Glad that you and Russ know all about this stuff.
     
  4. snj5

    snj5 F1 World Champ

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    #79 snj5, Feb 3, 2014
    Last edited by a moderator: Sep 7, 2017
    As Taz will agree, one of the problems with the coupe switch was loading of the plugs with oil if left cut to long. One precaution for me since I am saddling this thing up is to have a hotter ignition with some retro-fitted parts.
    For purists here, it still has a total loss oil system so the plane and I will be authentically covered in half burned castor oil.
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  5. tazandjan

    tazandjan Three Time F1 World Champ
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    #80 tazandjan, Feb 3, 2014
    Russ- Affirmative, a hotter ignition and wider heat range plug would help that problem. Fairly simple magneto on the originals.
     
  6. snj5

    snj5 F1 World Champ

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    #81 snj5, Feb 14, 2014
    The new manufacture 100hp Gnome rotary lives!!

    We are in line for engine #2 !!


    [ame=http://www.youtube.com/watch?v=FB80M6oAi5o&feature=c4-overview&list=UU6g3ZOXlxDKbtAK6ehOIYEQ]New Build - Monosoupape Gnome rotary engine "It Is Alive" - YouTube[/ame]
     
  7. tazandjan

    tazandjan Three Time F1 World Champ
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    #82 tazandjan, Feb 14, 2014
    Russ- Sounds great. Always amazes me how smooth a rotary is. The Gnomes are a bit louder than the LeRhones, especially the 9N.
     
  8. solofast

    solofast Formula 3

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    #83 solofast, Feb 15, 2014
    Unbalanced forces are a function of the mass, the radius and the square of the speed, so the relatively slow speed keeps the vibration down.

    A lot of what you feel as lack of smoothness in an engine is actually the uneven acceleration of the crank, that is, the engine is slowing and accelerating when each cylinder hits.. Until you get to 12 cylinders the flywheel is actually pushing the engine around for part of the rotation. Rotaries have a high rotating mass and this tends to damp out much of that uneven acceleration. Really old single cylinder ag engines, both steam gas and had huge flywheels and ran pretty smooth too.

    If you had that much rotating mass you'd probably rotate smoothly too....
     
  9. Bob Parks

    Bob Parks F1 Veteran
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    #84 Bob Parks, Feb 15, 2014
    Reminded of the little boy who encountered a tardy parishioner rushing up the steps of a Catholic Church.
    As she approached the boy she said, "Is mass out?" After looking at her for an instant he said, "No, but your hat is on crooked".
     
  10. tazandjan

    tazandjan Three Time F1 World Champ
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    #85 tazandjan, Feb 15, 2014
    SF- Affirmative, a flywheel is superfluous on a rotary.
     
  11. Tcar

    Tcar F1 Rookie

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    #86 Tcar, Feb 15, 2014


    Shoot, the darn near the whole engine is the flywheel...
     
  12. tazandjan

    tazandjan Three Time F1 World Champ
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    #87 tazandjan, Feb 16, 2014
    Just about everything except the crank and rear mount.
     
  13. snj5

    snj5 F1 World Champ

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    #88 snj5, Feb 22, 2014
    Last edited: Feb 23, 2014
  14. Bob Parks

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    #89 Bob Parks, Feb 23, 2014
    This place is NUMBER ONE on my bucket list. What a wonderful production!
     
  15. tazandjan

    tazandjan Three Time F1 World Champ
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    #90 tazandjan, Feb 23, 2014
    Russ- Wonder if she even has the variable power switch hooked up in her? Changes the timing order to cut down on power, all cylinders still fire, but mostly used on descent and for warm up at idle. Fred Murrin and I (mostly Fred) wrote an article on the 9N for Over the Front, which I think I mentioned before.
     
  16. FarmerDave

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    #91 FarmerDave, Feb 23, 2014
    When you talk about blipping the throttle... are you pushing a monetary-on or momentary-off switch?
     
  17. tazandjan

    tazandjan Three Time F1 World Champ
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    #92 tazandjan, Feb 23, 2014
    Dave- The blip or coupe switch grounds the ignition when depressed. Because of the high rotational inertia, as soon as you let up on the switch, the engine starts nearly immediately. On Gnomes, if the switch is left depressed too long without shutting off the fuel valve to the injector, fuel in the cowl can ignite. Not as big a problem on LeRhones and other rotaries with carburetors, because vacuum decreases when the ignition is shut off.
     
  18. SamuliS

    SamuliS Formula Junior

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    #93 SamuliS, Feb 23, 2014
    If you dont mind asking, how is the fueling of the spinning rotary engine done?
     
  19. snj5

    snj5 F1 World Champ

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    #94 snj5, Feb 23, 2014
    Last edited: Feb 23, 2014
    Taz -
    As you know, the original 100 hp 9B-2 did not have the variable ignition, nor does this one. According to Fred, I'm just going to have to get good at blipping. From what I read, it actually becomes quite natural and pilots liked the simplicity of it. Of course, you have to have some finesse to not overstress the crank. With the low power of the 9B-2 (as compared to the 160 hp 9N), I am hoping not a big problem. As the 100 hp Gnome was used on AVRO 504 and other trainers, the engine was also fitted to some Camels to aid with transition. Sounds like a good mix for me - a training engine on my favorite airplane. And, anyway, not planning on any real world dogfights. I'll have the wind up as it is. :)

    I do know that the first test runs with this engine use a modified modern Slick magneto. They are working with Emag to have a purpose built very high energy mag; will help the concern of oil loading up the plugs during blipped descent as well as start.
     
  20. snj5

    snj5 F1 World Champ

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    #95 snj5, Feb 23, 2014
    The fuel is passed through a hollow crankshaft into the crankcase, and then to the cylinder through ports in the bottom of the cylinder (Gnome) or through manifolds to intake valves (Clerget, Le Rhone, Bentley)
     
  21. Tcar

    Tcar F1 Rookie

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    #96 Tcar, Feb 23, 2014
    Read this thread?

    The castor oil/fuel/air mixture goes into the central crankcase.

    For the Gnome, look at the animation on post #64 on page 4. Intake valve is in the top of the piston, the air/fuel mixture is sucked from the crankcase below, through the piston, into the cylinder head.

    The LeRhone had big manifold pipes from the crankcase up to the top of each cylinder instead of through the piston.

    Exhaust is out through the top of the cylinder head.

    4-stroke engine.
     
  22. Bob Parks

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    #97 Bob Parks, Feb 23, 2014
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    My diagram from a while ago
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  23. Bob Parks

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    #98 Bob Parks, Feb 23, 2014
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  24. tazandjan

    tazandjan Three Time F1 World Champ
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    #99 tazandjan, Feb 24, 2014
    Russ- Affirmative, only the 9N fitted to the Camel and Nieuport 28 had that feature. Fred is the best on to get advice from, since he rebuilds them and flys them. A 100 hp Camel should be a relatively easy platform to fly and will be fun. Always the possibility of upgrading to a 9N once you have a lot hours under your belt.

    The 160 hp 9N, like the 160 hp SH.III for the SSW.III/IV, gave phenomenal performance to the Camel and N.28. Many of the USAS pilots were really chapped when they swapped the Nieuports for SPADs. Looking back at reports, the Nieuports had much better serviceabiliy than the SPADs and their problematic Hispanos. Of course the fabric did tend to come off the top wing on the Nieuports, but that was fixed. German pilots in early D.VIIs worried about N.28 performance.
     
  25. snj5

    snj5 F1 World Champ

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    #100 snj5, Feb 25, 2014
    One of the most polarizing topics on running rotory engines is oil. A degummed racing castor oil is available, but several rotory users in the recent past have happily insisted on dino oil. Some people insist that one must use castor oil because it is not miscible in gasoline and others loudly claim that this is a myth, and that castor was used simply because it was the best oil available in Europe at the time -- and that modern oils are just as good as castor (and much cheaper). And many "purists" vehemently insist that only original castor is to be used, and anything else will bring the apocalypse, citing the miscibility argument.

    The problem with castor? Besides quite expense at roughly a gallon an hour, even the de-gummed modern racing castor can gum up if not frequently used. With the original wartime castors, the engines would need to be cleaned and de-coked about every 20 hours. Modern oils, if useable, would greatly extend use periods. There was a study done after the war done by the USN showing higher quality mineral oil worked fine. And remember while the rotary is a standard 4 stroke Otto cycle engine, it does have a lot in common with 2 cycle engines as far as lubrication.

    So what am I going to do? Certainly a lot more research, but degummed modern racing castor is my default position.
     
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