hi, is there any chance that mvvs has adopted their newest engines for the us marked. I hear rumors that they have altered the compression ratio on the newest engines. my new 49 runs really weak on fuel with out nitro, but once it gets about 7% nitro it runs much stronger. I`m thinking to try even more nitro to see if it likes that. I`ve been reading all about how well they run on low or no no nitro at all, but as mentioned mine has no power on 0% nitro. what gives???

asmund:
Suggest to go directly to the source, manufacturer, dealer ect. for a for sure answer. Had a mvvs 49 with pipe on a fun fly3-d. Did not like the lack of power and sold it to a friend. Few months later had a chance to fly my old fun fly with the mvvs. It ran very well in the same home environment and prop size. Think thay may take a while to run in where they are happy, but thats my only experience with this motor, although there are a few in the engine cuppboard waitilng for a project/ But they are pilon engines I want to try. Trying to make a fast canard euro plane type go fast?

Asmund,


Please write about your setup and about how you performed the break-in.

What RPM are you seeing on what prop size?

Within 6-8 hours of running time, this engine will gain about 600 RPM, over what you see immediately after break-in.


MVVS still specify using another head shim, for fuel with more than 5% nitro (up to 15%).

I run the tuned muffler(3248) the muffler and header are close together. 15% synth, 5% castor and 5-7 % nitro.I could not tach it because of lack of light. I will try to tach it tomorrow. I preheated the engine with a heatgun to about 160 farenheit for the first start. wot and a little rich on the needle.I ran it for a while like this, then I leaned it a bit for a while, then I richened it a bit and so on. I monitored the temp all the time and the hottest it got was 212 farenheit, mostly around 180. I did this for tre tankfillings. I dont consider the engine fully broken in yet, but ready to get airborne.I will try to get a 12-4 tomorrow and give it a try too.

Asmund,


You are using too little Castor oil in your fuel!

From my own experience and others', including Pé's, these engine run much better with a lot of Castor oil in the fuel.
It is not a minor difference, but a totally different experience.

Anyone who experiences running difficulties with his up-to-15 cc MVVS and changes to high Castor fuel, within 2-3 tanks the engine transforms! I don't know the exact reason for this, but it is simply so!


Monitoring the exact temperature is redundant! You must only keep the engine somewhat richer than peak. That is all.


Give the engine another 2-3 tanks of with over 20% oil, mostly Castor.

Use a 10x7, or a 10x8 prop, for better cooling and then switch to the 12x4 for flight.

Patience is the key word here.

ok I will add even more castor today, and see if I can get some other props to try.