MP 3.2cc glow engine

Discussion in 'Finished Projects' started by ixb1, Jun 13, 2017.

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  1. Jun 13, 2017 #1

    ixb1

    ixb1

    ixb1

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    Hello Everybody.
    This is my latest engine project. I actually finished this baby in winter (january) ,but today was the D-Day.
    This photos presents engine after two runs . More runs during running-in process will be next.
    Parameters:
    Bore 16mm
    Stroke 16mm
    Displacement 3.2 cc or .19 cu in
    Used propeller Master Airscrew 9x4
    Fuel mix methanol/castor oil 74/26%
    Glow plug hot rated MPjet
    and a bit patience

    Video of second run. Rock and roll starts about + 1min :D


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    Last edited: May 19, 2018
  2. Jun 13, 2017 #2

    modelmotor

    modelmotor

    modelmotor

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    Hallo ixb

    What a beauty your engine is n't she lovely?!Do you have a planset from that engine which performs great and looks very OK to me?

    Lots of succes from modelmotor-The Netherlands-Europe.modelmotor is my forum/thread name.
     
  3. Jun 14, 2017 #3

    minh-thanh

    minh-thanh

    minh-thanh

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    I love your engine !!
     
    ixb1 likes this.
  4. Jun 17, 2017 #4

    ixb1

    ixb1

    ixb1

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    Hi
    Here i add plans for this baby.
    If you have any sugestions or found errors, tell me about this.

    View attachment mp 3,2.pdf
     
  5. Jun 17, 2017 #5

    minh-thanh

    minh-thanh

    minh-thanh

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    Thanks Ixb1 !! I will try do it .
     
  6. Jun 17, 2017 #6

    Mechanicboy

    Mechanicboy

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    Minh-Tanh, since you never build the ringless combustion engine.

    And other newbeginners too.. :)

    Follow my instruction how to lap the cylinder and piston:

    Lets take a look at a typical lapping job - that of producing a fine finished bore and piston for an IC engine. In fact, piston and bore are both lapped in separate operations (NOT both together). All of these operations will be carried out in the lathe (and I need hardly mention the importance of keeping lapping compounds off the machine, particularly the chuck and slideways). For the bore an expanding lap is ideal, and this should be some 3-4 times the total length of the bore. The first grade of abrasive would be mixed with light machine oil (10W or lighter) and liberally coated on the inside of the workpiece. Similarly, the slurry would be added to the outside (and inside assuming it is of the ventilated type) of the lap. The lathe would be started at about 300rpm (for a nominal 1" bore) and the lap passed rapidly through the bore, keeping it moving back and forth without it coming out the bore. How to hold the lap? well, perhaps the best way is with a 'floating' tailstock holder, and failing this holding with the hand is a method as good as any. Be careful when holding the lap by hand as it's possible it may jam, hold it lightly and expect the unexpected. Remember also that unless the lap is maintained dead parallel with the bore (an almost impossible task) it will tend to bell-mouth the bore a little - hence the reason for making the work a little longer than finished size and trimming to length later. When the inside of the bore has achieved an all-over grey appearance, with the fine scratches appearing even and criss-crossing both ways, and with no evidence of any deeper scratches (as might be left by the reamer) it's time to move onto the next finer grade. The work will have to be removed from the chuck to clean it properly, and this should be done with clean paraffin oil followed by hot soapy water. The same procedure applies to the lap and all traces of the abrasive must be removed. The process continues until you reach the 'flour' grade of abrasive by which time the finish on the workpiece should be very fine indeed. A final polished finish, should this be deemed necessary, can be achieved using metal polish (diluted Autosol, or some liquid chrome cleaner). Surface muct be smoth and crosshatched dull grey before last lapping with piston into cylinder with chrome polishing paste. The lap should be a separate 'finishing' lap so there is no chance of contamination with the coarser grades of abrasive which might be embedded in the main lap. The piston is treated in a similar way except of course the lap is female. Work will continue with the coarse abrasive until (using the un-trimmed bore as a gauge) the piston will not *quite* enter the bore. At this stage finer grade abrasives are used and work continues until the piston will just enter the bore tightly. At this stage, it is usual to finish mating the two parts by using metal polish and briefly using the piston to lap the bore directly. Great care needs be taken but this method ensures that the fit is good for the entire length of the bore.

    To create tapered cylinder: Piston create tapered piston when the piston is lapped into the cylinder at final stage.
    To test fit is correct: Dry piston/cylinder ---> tight to enter into cylinder. Oiled piston/ cylinder ---> The piston is loose fit in BDC cylinder and tight in TDC.

    In the drawings where cylinder material is made of steel also use high tensile steel as you can find in the old driveshaft from the car to example front drive wheel car where drive shaft is hard enough against abration. To machine the steel from drive shaft, the steel must be annealed first. Uneccesary to harden the steel again after the work is ended since the steel is hard enough due it's an alloy steel.

    Cast iron can you use from old cam shaft from car engine, between cam is cast iron not hardened who are good as piston material.

    It's my experience since i has builded some combustion engines such as model diesel engine and glowplug engine.
     
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  7. Jun 18, 2017 #7

    minh-thanh

    minh-thanh

    minh-thanh

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    Thanks Mechanicboy !! These tips are very useful and precious experience for me . :thumbup::thumbup::thumbup:
     
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  8. Feb 8, 2018 #8

    jasonmrye

    jasonmrye

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    Where do I find this specific glow plug at to buy? I am a High School Precision Machining teacher and I have a group of students that have latched on to the idea of building this engine. I am almost as excited about it as they are, but I'm a machinist/teacher and not an RC hobbyist. Can someone point me in the right direction and educate me as to what the specs/model number/whatever I need to know is about this glow plug used successfully in this engine.

    Any help is appreciated!

    Thanks,

    Jason Rye
    Lamar County School of Technology
    Vernon, Alabama USA
     
  9. Feb 8, 2018 #9

    Mechanicboy

    Mechanicboy

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    The right choice of plug can make all the difference to engine performance and reliability. The general 'rule of thumb' is: Hot engine = Cold plug and Cold/Cool engine = Hot plug.

    So, if you have an older, slightly tired engine or you prefer to use straight fuel you should choose a hot plug. If you have a high performance, high revving 2 stroke that is working very hard a cooler plug is a good idea.

    Always use four stroke plugs in four stroke engines, and they are also very good in inverted two strokes where starting and running at idle can be difficult.

    The Glow Plug can come in different ‘ grades’. These are usually termed as a number or as ‘hot’, ‘cool’ or ‘medium’. For most standard applications a medium to hot plug will be used. For a high revving engine, such as a performance model car or a ducted fan, then a cool glow plug will be used. The hotter the plug the thinner the element and the cooler the plug the thicker the element. The most common mistake is that a modeller with a performance ‘hot’ engine often thinks he should buy ‘hot’ plugs, when in fact he should be using the cooler plugs. A model club or a model shop will always be able to assist in the choice of plugs. There are many different manufactures and there are different price ranges.
     
  10. Feb 9, 2018 #10

    Cogsy

    Cogsy

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    Realistically, for a demo engine like this probably any glow plug will get it running. You should be able to get tons of them at virtually any hobby shop, or search eBay. The common ones used in RC cars should be easy to get and cheap.
     
  11. Feb 9, 2018 #11

    ixb1

    ixb1

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    Hello Jason
    This engine i designed (compression ratio and simple shape of combustion chamber) to use hot glow plug with long reach and straight methanol/oil mix.
    You can use for example plug OS no.6 ,Enya no.3 or plug of any other manufacturer (mostly cheaper).
    These plugs are available in modeler shops ,ebay,HobbyKing etc.
     
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  12. Feb 26, 2018 #12

    veedub

    veedub

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    ixb1
    The photo of the MP3.2 shows a shiny, aluminium coloured head but the body of the engine appears to be a matt grey. How did you get this finish on the crankcase etc?
     
  13. Feb 26, 2018 #13

    ixb1

    ixb1

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    The crankcase is sanded in vertical direction to remove machining marks and scratches.
     
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