Hey all,
I have two NIB MVVS engines, one is a .61 and the other a .77, I am considering options in case I cannot resurect my Hanno. Both of engines can be rotated to be RE, I would need to get a riser header to match. Has anybody had experience using one of these engines in a classic pattern type aircraft. I am limited to 12" props due to clearance, I was using 12x11 on the Hanno and would like to stay in this range.

Thanks
Steven<br type="_moz" />

Steven

I use a MVVS 61 on my Taurus and it is a very reliable engine, less complicated than the OS Max 61 FX I also use.
Never had a dead stick with this engine also not with a MVVS 7,5 ccm 0.45
I use the engine with the standard muffler and a fuel pressure regulator near the carb(as Cline). The regulator I always use.
The engine they give to me because they couldn’t handle it, I think they did use a wrong muffler or pipe.
The engine is very powerful but I do not have measured values, I only do data logging during flight.
I use a propeller 13 x 6 on the Taurus of about 4 kg.
Testing the engine I would do on a test bench, also to check fuel tank/engine position in “nose up� position without the plane.
If you have any question I will hear from you.
Do not forget after running do not change the exhaust position anymore!!!!!!

Cees

Hey Taurus Flyer,<div>Thanks for the inputs, my reluctunce to just them up is due to not being able to change back to SE at a later stage.  The 61 is the old black head MVVS with quite a strange carb on it, will give that a try in RE and see what it will do.  </div><div>I was told when I acquired my pattern ship that it was a Summit, never been confirmed, I have had to put a lot of work into getting it flying nicely as the wing dowels in the fuse had been worn and the wing incidences were all over the place.  Anyways it was flying very well and I was really enjoying it.  The issue with the plane is the tank is mounted in on the CG, so I will need to look at a regulated setup with a cline I have, I was considering taping the backplate for pressure, yours looks like muffler pressure, is this ok with the cline.</div><div>What fuel are you using, I know the MVVS like castor and little to no nitro, this could be a problem as I try to use 20% in everything.</div>

Steven,

The engine I show is without piston ring and for that reason I will not change the exhaust position after running,
I do no know about the ringed engine to change the position if possible.

I use Fuel with 5 % nitro syntetic oil but the engine is without ring, so I think a modern engine when we compare with yours!!!
We have to know that for sure!

I always use the muffler pressure and a checkvalve to have the max exhaust pressure of the muffler in the tank.
I do not know if this pressure is enough for you, but you can try on a bench, put the tankposition on the low level just like the nose up position of the plane. So the same vertical distance

The muffler tap I do find the best for me, simple.
Be aware of the pressure of a crankcase tap, that can be 7 psi I think! and for sure when you combine the crankcase tap with a checkvalve. These pressure I do not like in my tank in the plane.

I never use a tank in CG position. If you do you need a pressure in the tank to get the fuel above the engine in nose up position and also during iddle, that's the reason of my chackvalve.
Let it be clear, I do not use the tank in CG, so maybe there are other pilots with experience to tell us the facts.

I can put my plane in any position without any influences on RPM even nose down.
Nose up the "trapped" tankpressure by the checkvalve is enough to get the fuel above the engine and the regulator does reduce the pressure to barometric even with nose down of the plane. That's the way the Cline works also.
The little brass tube near the carb of the engine is the pressure measuring tube for the regulator beside the engine. This way the dynamic + static pressure of the regulator is the same as the air inlet of the carb.
(The plastic tube is the cold junction of the thermocouple of the engine temp measurement)

Cees

Cees

That's correct MVVS's engines dont like nitro higher than 5% or even better use FAI fuel, east europe engine designs have this particular "problem" if you can call it so, im sure they did it for economy reasons.

I wouldnt run it on syntetic oil only add some castor also, engine will thank you for that.

rafa,

Thanks for response.
The big difference in the way I use my engines is, I always use a Cline like regulator. I always have a good fuel air ratio and use 10 % synthetic oil and 5 % nitro!!
Both MVVS engine do work great with this mixture but I cannot give advice to others
The castor oil can be needed to convert the heat of the piston to the cilinder/liner wall when the mixture became lean.
When using a cline regulator you always need a tankpressure more than the "hydrostatic" distance between tank level and spraybar, so nose up, with nearly empty tank.
When not, you can run the engine "lean" result will be overheating.


When I need it, new fuel mixture, other plug etc. I use temp. detection and data logging for a period on the head near the plug to detect over temp during flight.
Absolut temp max is 185 degrees C ( 365 F?) for my glow engines.


Cees

It is going to be two weeks before I can get the engine on the bench to try out, I have a 5% Castor/Synth blend which I have used for running in motors in the past, I will start of with this and see how it goes.<div>My tank is around 250mm away from the engine, as mentioned before I cant move it closer.  So I think I will tap the backplate of the motor, have a non return to presurise the tank and a cline to regulate it prior to the stock carb.  My other option is I have an old YS vibration pump which can be installed but requires a return line to the tank.</div><div>To many options - not enough time .....</div>

Steven,

When you use a backplate tap on the engine I would not try the nonreturnvalve in the connection between the tap and the tank in the first place.
The pressure can be too much for the tank and than you have really troubles.

When using a tap on the backplate I would try a restriction between this tap and the tank in the first place.
In the tank the result will be the average pressure and that can be 3,5 PSI, 50 % of the 7 PSI, I do not know for sure but I think.
This pressure is more than enough , good for a fuel height above te plane of about 3 meter, 10 feet.
The restriction prevents the pressure drop too fast when idling the engine.
The position in the air, nose up and engine idle, will normally not be long!

Provit of this set-up is the presure will drop to zero after a short time the engine stops.
A non return valve will keep the pressure high in the tank so the tank can leak fuel and for sure when the tank is full and the temperature rises..

I do not have experience with this set-up, but it seems to be more logic. Maybe other members have advice?

Cees