joelsaxton

My Feedback: (10)

http://morrishobbies.com/mvvs/58cc_gasser.html

This is coming out soon. I have a hard time believing these stats, but who knows?

Joel

Icebird

I just used a program that I have that calculates HP, and according to the prop example they give, it's 6.8 horse. Still decent, but not exactly the 9.25 they're claiming. These guys seem to have a habit of over stating power numbers! The ZDZ 60 sound like comparable performance.

DKjens

My Feedback: (50)

Morris Hobbies lists an introductory price of $600.00 for this engine, so will it go up after the introduction. I would buy one and be a "guinypig" if I could get it for $500.00. The DA-50 is one of the greatest power to weight engines right now. Who knows, the new ZDZ50NG may be as well, it just has not been tested and proven yet, as well with the "coming" BME55Extreme(thank you Gerry). I am probably going to Europe at Christmas and will see what one can be had for over there.
DKjens

viper16

A nice looking engine that even I might consider, one thing that would have been nice to see on this engine would be a angled spark plug,rather than vertical,for more clearance. IMO

f2racer

I spoke to Robert over at Morris. The rpm figures that they list was from a prototype unit that was brought over from the Czech Republic a while back using a prop they had on hand for testing (they only tried one prop size). The HP figures are taken from a production engine on a dynamometer (no prop) at the factory. There will likely be some loss of power by simply mounting a prop onto the engine, so the factory spec of 8HP should be pretty close to what folks will see when prop-ed right. That should equate to 2-3 or so more HP than other manufacturers 50-60cc engines. But I guess time will tell...

BobH

My Feedback: (2)

It's hard to imagine an engine in the 50 cc range having a 25% increase hp over other engines in the same class?? I can't imagine where the additonal energy would come from? The MVVS doesn't appear to have a super charger or an external ram induction that would aid in thru put of fuel/O2. Doesn't seem to have a super exhaust system either?. I'm not trying to be critical here I guess I'm just sketpical for now given what I can see. BobH.

P-51B

My Feedback: (5)

Its magic.

Icebird

I'm not going to say that anyone is lying, but past experience with MVVS has shown me that if you get an engine that was assembled when they are having a good day, you have a decent engine. Unfortunately, they have too many bad days, and I've seen the results. Over stating performance numbers also seems to be one of the things they do well. IF there was another 25% performance on the table, don't you think the other manufacturers would have found it too? As I've always said, figures don't lie, but liars can sure figure.


Color me VERY skeptical!

ptebbe

My Feedback: (27)

It's magic, alright. And it's not included in the base price...

f2racer

I got the latest update from Robert over at Morris. The production 58cc that he's been testing on a Giant-Scale Jerry's Big Boy is spinning a wood MAS 24x10 prop right around 7000 rpm using a kludged muffler setup. That's right around 8HP in the Thrusthp app which is a bit optimistic from what I understand. Robert believes that the prop is still too small for the engine. How well do other manufacturers 50-60cc gas engine do with that prop?

Thanks!

Volfy

My Feedback: (23)

Just as automotive engines show differences between dyno bhp off the crankshaft and "road hp" at the driven wheel, these aircraft engines will show different hp figures depending on how it's measured.

As mentioned, the 9.25hp is dynoed at the crank at the factory. Thrust-derived hp numbers will differ greatly from prop to prop. The only true way to compare apple to apple with these aircraft engines is to apply a known load (non-aerodynamic) on the engine and measure the output. A MAN article a while back does exactly this on a bunch of .60 glow engines.

ptgarcia

My Feedback: (36)

How much does it weigh?

f2racer

According to the MVVS catalog, 1630g. Don't know if that's weighed with ignition or not, but for a frame of reference the same catalog lists the 35cc at 1650g with ignition.

bobi

just heard of some numbers of this 58cc engine (testing)
24 * 10 mejzlik 2 blade @ 7400 with full tuned pipe
26 * 10 """"""""""""""""" @ 6500 """""""""""""""""""""

the info came from a friend of mine who is importing Mvvs engines to his country.
Just hope the production series will come out good then there will be another good choice in the market.

Hans Meij

These numbers are repeated here:
http://www.modellbau-bichler.de/date...p?kategorie=17

Diablo-RCU

My Feedback: (1)

They need to start work on an 80cc motor to compete with the ZDZ-80. Hopefully the latest Vlach ignition units are better than the early versions (which seemed like they were designed by Joe Lucas). The other Czech ignition (Falkon) appears to be bulletproof from what we've seen around here on all the ZDZ motors.

f2racer

Again, how we'll do the numbers that have been published compare to other folks 50-62 sized engines? If it's really quite a bit more powerful, and lighter than other peoples 60s, it may be the perfect powerplant for the new wildhare edge... I've already got an MVVS 2.15 gas coming for a GP Pitts (not expected to 3D), but I'm looking to start an even bigger project over the winter.

Thanks!

DKjens

My Feedback: (50)

I've spoken with Martin Biichler, and I'm set on getting this engine for my WH Edge. I have a Brison4.2 and a ZDZ80RV, both practically new, I only need one of them for my 30%Cap231EX, so as soon as I sell one of them, I am getting the MVVS.
DKjens

apalsson

My Feedback: (1)

According to my thrust calculator program, that's 8.13Hp, not 9.25.
Still some inflated figures, huh?

DKjens

My Feedback: (50)

I have to admit, I haven't really payd attention to the HP ratings publicized for this engine, or any other for that matter. Horsepower is irrelevant in these applications, it's the torque that turns the prop at the rpms we are dealing. I have been waiting to see real test bench figures on this engine, such as what have come from Morris Hobbies and from Martin Bichler. This engine with a free breathing exhaust looks to be as powerful, at least, as the ZDZ80RV, but lighter, and that's what matters to me. I have a ZDDZ80RV if I wanted to use it for the next plane, but I'd rather go lighter and use the MVVS58.
DKjens

pe reivers

The numbers and figures that Bichler published, are obtained on a dynamometer in an optimized setup with reso tube. The values are true for that particular engine. Since then, MVVS has been working their ass off to get the engine production ready, and in all fairness, this could well include some minor dyno result changes. Miracles are wrought in heaven as we all know. However, the published 8 hp, are by no means a miracle, but still quite good figures for 58cc. I obtained 9 hp out of 50cc in my motocross engine at 12000 rpm, whilst some rode 12hp at 17000. In my younger days, that used to be a national class. I finished all the time, they often failed to do so.

The prop load is very similar to the dyno because it acts as an air brake. In fact, calibrated air brake props are used for power measurements by the better engine columnists.

Thrust-HP is an extremely unreliable comparence tool, because it fails to take prop pitch into account for static rpm loads. According to this program, you can either fit a 18x6 or 18x12 on the same engine, and get the same thrust and rpm. Makes sense? I don't think so.

The program is based on the principle, that under certain thrust conditions <IN FLIGHT> the blade angle of attack in the prop slipstream is identical for all prop pitch values. This condition is very much different than our measuring conditions, so IMHO, the program is next to useless.

Diablo-RCU

My Feedback: (1)

6500 rpm on a Mejzlik 26x10 with a tuned pipe is very good for a 58cc motor. However, it isn't equal to the ZDZ-80. My ZDZ turns 6700 rpm on a Pitts muffler. I would expect it to turn over 7,000 rpm on a tuned pipe, although I haven't run one myself.

Kris^

My Feedback: (1)

If I may interject. .a lot of this prop spinning stuff has to do with exhaust setup. Like the ZDZ80, which really perks up and runs hard when a properly developed tuned exhaust is bolted on, this MVVS will do the same thing. A few things to consider.

First, it's a single cylinder, the most efficient way to get CC's to make hP. Flat twins lose about 18-20% of power compared to a single of the same displacement, mainly due to increased drag and less efficient intake flow.

Secodnly, take that single, get the PERFECT exhaust on it, and it's gonna roar. Dick Hanson has reported over 7000 rpm from a 26-10 on a ZDZ-80, so it IS possible.

Third, if you totally optimize for that "magic" rpm figure, what just happened to the midrange transition and smoothness? I daresay it went to hell pretty quickly.

Lastly, look at the engines overall weight.. This is definitely a very "robust" and over-engineered piece of engine. If you go strictly by power-weight ratio of the engine itself, and forget cc's, the ZDZ80 is a better buy, as is the BME 110 Xtreme, both of which weigh within a few ounces of this "magic" engine, yet make a lot more power and low-end grunt, without the need of a "tuned" exhaust system, though the ZDZ80 gets much better with a pipe on it.

It seems that MVVS buyers will be happiest with this engine only at hi-rpm time, when they can brag abut the "power". Given the constraints of porting, compression, ignition timing and various factors to consider with these engines, there are tradeoffs for every situation. 60cc's making a gang-load of top end power is going to have to give up a LOT when it comes to midrange. It would make a great 60cc class "speed" motor, but the weight, including pipe setup, gets up ther pretty quickly.

I'd like to see some RPM numbers WITHOUT an optimized exhaust system. Lets bolt on a "pitts style" muffler sized for a 60cc ZDZ, then see how the MVVS fairs.

In the "Real World" of un-optimized exhausts, differing props, needing smooth mid-range transition, and having to run the engine day after day, I have a feeling the MVVS will not prove to be as much of a "wundermotoren" as the hype suggests. Yes it will be strong, I'm sure, but get it off the bench, into a plane, and put a normal exhaust system on it. . . .then brag when the 1000 rpm drop takes place.

Remember the "6000 rpm" 3W106 with a Menz-s 30-10 from last year?? On the bench, in the 3W factory, it supposedly turned 6000 rpm. . tales since then say the power was really about 5800-5900, and then only for a moment until the engine heated up, in which case the rpm dropped to about 5500. This was with a totally optimized exhaust system, cold engine and perfect conditions. You gotta ask, though, how many props they tried and "massaged" to get that number (a menz 30-10 is also only 29.25" in diameter, btw) since then we've seen reports of aobut 5500-5600 with this combination, in airplanes, cold rpm, and about 5350-5500 hot. THAT'S the REAL world, folks.

When the MVVS gets off the bench and into an airplane, about 100 airplanes to be sure, then we'll have real-world numbers to compare to. In the meantime I'll just sit here and stroke my BME 110Xtreme, that weighs only 3 ounces more(3 lbs 10 ounces versus 3 lbs 13 ounces, bare), swings 28-10 Mejzliks in excess of 7000 rpm HOT, has a GREAT midrange and idle, and does not really NEED pipes to make good power numbers (6900 without pipes, standard exhaust, hot).

Diablo-RCU

My Feedback: (1)

Say Kris:
Yes, a single has some advantages over a twin with less friction, but a twin has the advantage of more port area. This assumes similar bore/stroke ratios. The ratio of port area to cylinder displacement is inversely proportional to cylinder diameter.

Kris^

My Feedback: (1)

I'm aware of that Diablo, but there are a ton of other factors involved, not the least of which is overall efficiency of design. There is better efficiency in getting the mixture into the cylinder on a single, no problems with "balancing" the flow between two cylinders (one of which is always weaker) the mixture is set for one cylinder only, so there are no rich-lean differences (even if you had equal flow to both cylinders), the overall reciprocating mass is less.

The flat twin is a "Compromise" engine. It has much better dynamic balance than a single of the same displacement, but it tends to also weigh more (for the same displacement) and be less efficient overall.

I'm going to wait until we see a lot of "real world" numbers that do not come frm the factory till I pass judgement on this one. The rpm figures are just a WEEEEE bit excessive to be credible. (gonna get a BUNCH of flames about "well, what about the XTREME. . huh huh huh?? )