Is 200cc (6.7 oz.)enough to run this eng. on 10%nitro,20%oil with pipe set up? Plane Wgt. will probably be in high 60's .

Derek Pickard in an engine test reported that his MVVS 49 -

"Running 20% oil and 5% nitro, this MVVS handled
the test plane through the F2B pattern for only 90cc of fuel.
Such a light fuel load definitely helps to offset the ounce of
extra weight of the thick-wall exhaust. Upping the nitro
content to 10% raises power a touch and a fuel capacity
closer to 100cc is needed."

But what is your 'pipe' set up?

How many ounces is 100cc?  90cc?

BIG Bear
RNMM/AMM

100cc = 3.3814022558900003 oz

90cc = 3.0432620303010003 oz

A 4 ounce tank should be pretty much on the money for 10% nitro.

Thanks, Chris.  With that low of a fuel consumption for a .49 engine, it appears that more power would be available with bigger venturi, etc..

BIG Bear
RNMM/AMM

Bill, I am no expert on this but the MVVS engines that I have seen thrive on straight FAI fuel with no nitro (or as little as 5%) and keeping the compression ratio high - and they make good usable power in that form.

Why would one bother to chase more power at the expense of a reliable run?

I wondered where that came from originally. It does run better on FAI fuel. If you want to run yours we can go out to the Woodland site. It is in good shape and very flyable. You can access Randy's tuned pipe chart on Heman's "Aeromaniacs" site. It will give you a starting point for length and RPM. I too am curious how it runs.

This is a later production eng. that came with low comp head for use with aprx. 10% nitro type fuels . Pete ended up with my spare that had the two piece no nitro head. (green anodized.) I have a Randy smith pipe I bought for it several months ago. He calls it an Ultra torque pipe. I need to dig through my papers and find his suggested pipe length and RPM settup.

Hi Gordon,
                 I have two MVVS 49's, the glow one with a green head but sports a new liner with the latest trapezoid shaped transfer ports, Akrobat rear pipe and one that is dieselised, side exhaust and is intended to be side mounted.

Most of the comments that I have read regarding MVVS's centres around the power to weight to capacity ratio, they do seem a tad 'solid' for their capacity but the power they make seems to make up for this - if all of that makes any sense!

Its their solid nature that tempts fliers to put pipes on them, and well ........... put diesel heads on them.

Chris If I ever pick up another one of these I would be real tempted to dieselize it! It is built like a tank.

Gordon, over the years I have picked up many tips on the 49 diesel setup (many thanks to Keith Renecle and others) and a 'tank' is an apt description.

Smells like one too!