MVVS Twins
#26
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RE: MVVS Twins
Hi Fujiman!
I acquired one of these engines not long after we exchanged a few emails a while ago.
For my other thoughts on fuel distribution, please jump to the "MVVS Twin" thread in the "Everything Diesel" forum.
I will follow the deflector route, but will secure it to the plinth with two small countersunk head machine screws or similar.
My engine was received 2nd hand. However, it has fantastic compression and the desirable black factory pitts silencers. The intake hole in the plinth has been bored out to circular by a previous owner. I am in two minds about the benefit of that. What you say is true ... but, also, the engine will only flow as much fuel as the reeds can admit. If the factory thought it would have been worth it, they would have made the intake circular, which when you consider it is a much more straightforward manufacturing step.
Food for thought there.
If mine does not work well, I will make an inverted "top hat" countersunk into the plinth, and plug the intake, and then mill the intake aperture back to as near to factory as I can get it! Hopefully that will not be required.
I acquired one of these engines not long after we exchanged a few emails a while ago.
For my other thoughts on fuel distribution, please jump to the "MVVS Twin" thread in the "Everything Diesel" forum.
I will follow the deflector route, but will secure it to the plinth with two small countersunk head machine screws or similar.
My engine was received 2nd hand. However, it has fantastic compression and the desirable black factory pitts silencers. The intake hole in the plinth has been bored out to circular by a previous owner. I am in two minds about the benefit of that. What you say is true ... but, also, the engine will only flow as much fuel as the reeds can admit. If the factory thought it would have been worth it, they would have made the intake circular, which when you consider it is a much more straightforward manufacturing step.
Food for thought there.
If mine does not work well, I will make an inverted "top hat" countersunk into the plinth, and plug the intake, and then mill the intake aperture back to as near to factory as I can get it! Hopefully that will not be required.
#27
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RE: MVVS Twins
whenever I work on reeds for tuning, I trumpet shape the intake duct toward a shape about 1mm inside the reed outline, just like in 4-stroke valve tuning. That way I have max reed operating pressure, max flow area, and lowest flow velocities at the reed circumference. These velocities tend to shut/restrict the reed valve due to Bernoulli effects.
These effects also can be used to direct the main flow path if required, without restricting the flow like a baffle would do.
These effects also can be used to direct the main flow path if required, without restricting the flow like a baffle would do.
#28
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RE: MVVS Twins
hi pe, i think i understand, but could be clearer on what you said with maybe a diagram drawn and posted here. your expertize is always a big help here on rcu. thanks, bill b. (fujiman)
#29
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RE: MVVS Twins
No pictures available.
Just draw the reed outline. Then shape the inlet duct to stay 1mm clear of the outline, so the reed has some flat sealing surface left.
Smooth curves in the duct approaching the reeds provide better flow.
Shaped thus, the reeds will lift sooner, and also close sooner to avoid blowback.
Just draw the reed outline. Then shape the inlet duct to stay 1mm clear of the outline, so the reed has some flat sealing surface left.
Smooth curves in the duct approaching the reeds provide better flow.
Shaped thus, the reeds will lift sooner, and also close sooner to avoid blowback.
#30
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RE: MVVS Twins
Hi Guys
I have just purchased a 1.44 twin with headers its 2nd hand and has the walbro type glow carb fitted, where can i get some effective silencers for this engine and what prop do you recomend as i have no instuctions.
Regards
Major Splat.
I have just purchased a 1.44 twin with headers its 2nd hand and has the walbro type glow carb fitted, where can i get some effective silencers for this engine and what prop do you recomend as i have no instuctions.
Regards
Major Splat.
#31
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RE: MVVS Twins
The 10cc muffler parts are used for this twin.
Do a forum search for general information. A lot has already been written.
http://search.rcuniverse.com/search....+twin&start=30
Do a forum search for general information. A lot has already been written.
http://search.rcuniverse.com/search....+twin&start=30