MVVS 45 & 49

LAST EDITED ON Oct-30-04 AT 11:50 PM (CDT)
 
Has anyone used these for stunt? I got 2 of the 45's with 4 bolt Red Head and 1 of the Green Head 49's. I remember a article in SN a couple years ago about the 49 but haven't seen anything regarding the 45. Any success stories out there? Can they possibly be more entertaining than a engine that is less than 21 but more than 19?

Bill

I've got a .49 with a ventre done by Scott Reise (SP)
I don't know much about it so I'm curious fo answers
too.

The Ground rarely loses.

>I've got a .49 with a ventre done by Scott Reise (SP)
>I don't know much about it so I'm curious fo answers
>too.

Me too. I have a .49. I will build a plane for it if it's any good.

I have run the green head .49, set up rear exhaust with a header available from MACS. I ran it on an old S&W pipe for a 40VF. It shows promise. The plane I had it in was nothng special and had limited tank height adjustment, so I cut short my testing 'till a better plane could be built.

It weighs a bit less than a Tigre 60 or 40VF, but is heavier than the PA series. It has a metric shaft which makes props & spinners a pain, but the shaft is pretty long, so a cool cowl can be carved.

I look forward to playing with it more this summer.

Anyone else tried it piped?

RC

>I have run the green head .49, set up rear exhaust with a
>header available from MACS. I ran it on an old S&W pipe for
>a 40VF. It shows promise. The plane I had it in was nothng
>special and had limited tank height adjustment, so I cut
>short my testing 'till a better plane could be built.
>
>It weighs a bit less than a Tigre 60 or 40VF, but is heavier
>than the PA series. It has a metric shaft which makes props
>& spinners a pain, but the shaft is pretty long, so a cool
>cowl can be carved.
>
>I look forward to playing with it more this summer.
>
>Anyone else tried it piped?
>
>RC

You can get metric adapters for the spinners. I have some 3-blade spinners with all sorts of metric adapters. The biggest down side I see to the engine is its weight. There are lighter engines out there these days of the same size. But, other than that, it appears to be a good engine and there should be nothing wrong with using it. Put a light weight muffler on it, or, if you use a pipe, I would opt for a 60 size pipe over a 40. You will get more power out of the engine that way.

the check kid who finished 2nd in the world juniors was running a mvvs .49 but i do not know the vintage...

anyway else know?

I have been running MVVS .49’s now since the 2000 world champs, and I must say that they are really good stunt engines, even in their stock form. The standard 45 and .49 R/C engines are not the same at all. They have wild timing, and will not work well for stunt. I also had a look at the Czech junior’s model in Muncie, and he did indeed use a stunt .49 with an aluminum tuned pipe. I was told that Jiri Vejmola (4th place) also used the same set-up. The South African Junior, Callum Orbell, used a stock standard .49 stunt in his Spitfire that was well photographed. The only real change that we needed to do, was to use a Thunderbolt 4-stroke plug, and it ran quite well in the changing Muncie weather.

It was a pity that my own good model bust it’s outer wing right off in practice, because it was performing incredibly well. I used the same .49, but with a diesel conversion. I have totally abused a couple of these engines in getting the set-up working, and I have yet to wreck one of them. The only hassle with them is in using them in side-mounted mode. All MVVS engines up to the .91 have extra cavities inside the crankcase for changing the configuration to side or rear exhaust, and running on the side, they store up oil in the spare cavity under the exhaust port. This comes flying out when the model performs outside loops, and kills the engine, or it just burps badly. My diesel runs at lower rpm, and I found out that I also needed to block the boost port as well.

Running inverted or upright, is no problem. I changed the 5 mm sprinkler venture to a fuel post (spigot) type, and narrowed it down to 4.8 mm. The older engines had a safety NVA mounted on the backplate. This is not the best system. The new MVVS stunt .49’s have the NVA up front as per the Super Tigre etc. Depending on the altitude, you can add head-shims. The standard shim is .2 mm, and I have never added more than another .2 mm shim. Just one important point to remember, is that they take a fair amount of running before they become real nice engines. I have found that after about 1.5 hours thay just start to settle down. After 2 hours they are great.

Our other team member, Loren Nell, tried one on a tuned pipe a few years ago, and it turned the same 3-blade prop from his OS 46 VF, a little faster. Overall, I would say that it is a very under-rated engine, and it comes at a very good price. Please let me know if you need any more info.

Disclaimer: I am the South African agent for MVVS, so everything that I’ve mentioned here is most likely biased and distorted!!

Keith R

Oh, I just remembered something else. The green head versions are the older ones with the two-piece button head insert. The new gold head is a one piece head, and has a different combustion chamber shape, and a slightly lower compression. I liked the old green heads, because it was easier to make the diesel conversions, but the new gold heads seem to work better on glow.

Kieth, what are the standard 45's good for?

Bill

LAST EDITED ON Oct-31-04 AT 09:41 PM (CDT)
 
Bill
Thought I'd come in on this one! I have been using the RE/Rear intake MVVS 51 (49??)since around late 1995. For the world champs 2000, I enlarged a "Grondal Nobler" 15%. The model was a little heavy for my liking at 62 oz ( Totally pull apart for ease of transport added a few oz) but the motor, as normal, performed great. The only repair from 1995 to pre w/champs for 2000 was the renewal of the bearings. The motor performs great on standard 4:1 castor base fuel. The altitude in France required a bit of a nitro tickle of around 5% but the same fuel almost gave too much power at the British nats of 2000 ....... just too tired (or lazy) to change the setup after being away from home so long! About 95 cc of fuel is all that is required for a 6min 20 sec run on an 11.5 x 5.5 2 blade C/F Eather prop. The muffler on this R/E is the standard MVVS mini pipe? setup. It gives a different sound to other engines and yes! I have been told that I would have scorred better at a couple of comps here in OZ if I used a different muffler!! Makes you wonder what the judges are looking for when they judge the sound and not the manoeuvre!

Good luck with a great engine.

Regards from OZ

Dallas

PS The engines I have use a std M7 x 1 thread so it shouldn't be a problem getting a suitable nut.

>Kieth, what are the standard 45's good for?

The timing is as per normal hot R/C engines, and I suppose that you could do some porting mods, but it may just be better to sell it to some R/C folks. I am testing a standard R/C .49 on a diesel head, and this seems to rev higher the the stunt version, but so far I have not yet run it in for long enough to draw any useful conclusions. My Magnum XL 46 runs very well on diesel, but it has a short stroke, and therefore has lower power by far than the MVVS 49.

LAST EDITED ON Nov-01-04 AT 11:38 AM (CDT)
 
I have 2 of these. One of the older green head versions and one of the new gold head. The green head is set up side exhaust and the gold head rear exhaust. I plan on using these interchangeably in my next plane.

Dave Simons (who posts here) recommended I speak with Paul Lagan (New Zealand) who was competing in the 2004 WC. Paul runs these engines on occassion. Incidently, Paul was running a complete Yatsenko setup (Retro 60) at Muncie. Paul was very informative. He had positive comments on the MVVS .49. He uses large diameter props and the large F2B mufflers, as recommended by MVVS.

I have the large side exhaust and rear exhaust mufflers, so I tried both engines (on the bench) with a 13x6 Zinger (cleaned up a bit) on 5% nitro, 20% 1/2 and 1/2 oil fuel. Both engines turned this prop in a solid 4-stroke at 7600 to 7800 rpm. The older green head was the faster, but it has a lot more bench time. Incidently, I have decompressed the green head version as the chamber volume was quite small. Both engines needle well (not fussy) and do not overheat while turning this big prop (heavy load) on the ground. Very promising.

Fred

I have a 40 which is great. Here's the blurb on a 49. Says it all?
http://www.justengines.unseen.org/MVVS49sr.htm
Adrian

Unfortunately, as is usual for the writer, the stock engine was never tested - so, we'll never know. The MVVS has a good reputation in lots of places & with knowlegable people. Paul Lagan mentioned that it likes big props & the best he found was a 13.4/5.9 Yatsenko.

What size prop do you run Herb?

I have tried many props, but so far I've found that a good 12 x 5 wide blade like the old Topflite paddle, seems to be best. The Zinger 13 x 5, cut down to 12", also seems to be reasonable, if you round the tips a bit. We fly at 5000 to 6000 ft her in Johannesburg South Africa, so props are critical. I have tested props in 1/2 inch steps from 12 to 13.5", and the 12 x 5 suits me best. I also use 5% nitro, but at sea level the MVVS is happy with no nitro.

My diesel .49 swings a 13 x 6 Rev-up, very happily, but then the ground clearance and turn rate suffer. All of this, of course, is relative to the model design, and your own personal preferences.
For the price, it is one really good engine, and it's performance record shows.

LAST EDITED ON Nov-03-04 AT 08:15 PM (CDT)
 
Reply on props to Dave Simons.

Dave, I tend to like a free spinning engine and have resisted going over a 12" diameter on even the ST 60. The MVVS Rear Exhaust/Rear intake 51 seems to like this setup and at first I used an 11.25 x 5.5 Eather 3 blade C/F prop. Why the 3 blade? I liked the static look of it on the USA-1! The model flew just as well on the 11.5 x 5.5 two blade prop.

As you may be aware, here in OZ, the MVVS 51 model I use was given quite a rubbishing by some regarding the tank position problems, starting problems because of the rear intake etc etc. As we know from experience, none of this is true and it only took one model to get the tank at the correct height to give a great reliable run. Yes, the engine is a bit heavier than others such as the old reliable ST 46 but how much more fuel and tank weight do we have for the same power as the MVVS.

After our 2000 Nats, I passed some info on to Paul Lagan as he had the same engine in NZ. Not sure how he got on.

Herb H

Yes those engines are usefull for stunt and as mentioned earlier some of them was also in WC in Muncie.

We here used it extensively for many years. The most favorable was rear intake rear exhaust installed sideway with light muffler reworked from pylon "magic muffler".

It is relatively heavy engine, with very good power but it is certainly not that "right out of the box" type engine. In past they had lot of problems with quality and tolerances, now they improved, but anyway, as far as I know, guys using that engine must still do some mods before serious usage. On opposite side it is brobably the best engine for playing and making mods - lot of metal and screws, exhaust can go to any side, retiming no problem ...