Miketc

I need comparison data to help make a decision on which engine I should use in a Composite-ARF 2.3m Extra 330L (Span: 230 cm (90") Length: 195 cm (77") Weight: 9-10 kg (20-22 lb) Engines: 50-70 cc

This is what I have found on line or in the manual, feel free to correct any errors I might have made.

MVVS 58
Displacement: 3.6 cu in (58.2cc)
Horsepower: Approx. 8.5 hp @ 6950 rpm
Weight: 1985g incl Ignition (1820 g + 165 g) (70.0 oz)
Prop Range: 22x10, - 26x10 - 22x10, - 24x12
RPM Range: 1,000-7,500
Ignition voltage: 6V
Price: $600 excluding muffler

ZDZ 80
Displacement: 79.8cc
Horsepower: Approx. 9.5 hp
Weight: 2000g (4.42 lbs) (70.5 oz)
Prop Range: 24 x 10 - 28 x 8
RPM Range: 1000-8500
Ignition voltage: 4.8-9V
Price: $ 800 excluding muffler


DA 50
Displacement: 3.05 ci. (50cc)
Horsepower: 5 hp
Recommended Props: 2-blade: 22x10,- 24x8. 3-blade: 20x10 - 22x10 narrow.
Weight: 1334 g (2.94 lbs) (47.1 oz)
Length: 6.7" (170mm) with stand-offs
Ignition voltage: ???
Price: $595 excluding muffler

Mike

DarZeelon

Mike,


The DA is a nice engine, but in comparison to the MVVS and the ZDZ 80 cc, it is heavily outclassed power-wise.

The MVVS and the ZDZ are close.


Just from your overview, the MVVS has the DA's low price and the larger displacement ZDZ's power.

Miketc

Thanks Dar Zeelon,
I have the MVVS 45 in my H9 Extra 260, the motor has on +- 9 lt through it, and pulls like a demon with the MEJZLIK 22 x 10
What is the MVVS 45 like in comparison to the MVVS 58? In pulling power vs weight ?

Mike

DarZeelon

Mike,


The 45 cc and the 58 cc are very similar in design.

The power difference is quite coherent with the displacement difference.


The current 45 cc (actually 43 cc) engine is made mainly of magnesium, so it is significantly lighter than the 58 cc engine.

NikolayTT

Hi Guys,

Isn't kind of clear (unless one wants to fly a motor-glider) that more power is better especially
with the similar weight of the hardware ? - The question seems a bit confusing to me; I would
go for Max-Power and try to "fit" it within the fuselage. The fuel weight is not a big dilema in
gazoline engines. So obvioulsy I need to ask why not ZDZ 80 as an imediate choice ?

pe reivers

Not so.
Light flies better. So If you have enough power with the smaller engine, plane performance does not improve by fitting a larger engine. Verticals get annoyingly fast, and manoevrability goes down the drain.
An overpowered plane only is good to bank-n-yank, which has nothing to do with flying. Too much power in a light frame, like for 3D, will shake the structure apart from torque oscillations only. Not the best buy either.

Having said that, the 43cc MVVS excels over the DA50 in low rpm, but looses slightly in higher rpm. For 3D, my money goes to the MVVS for prop acceleration. For sheer power, the DA wins.
The mvvs 58 and ZDZ 80 are not in the same class, and should not be discussed at the same level as the 43/50. You would not want to compare a glow .90 to a glow 1.60 would you?

NikolayTT

Hi,
I agree with the comparisson of a glow .90 to a glow 1.60 but I think the discussion is more about comparisson
alike of .61 to .91 because the MVVS-58 is 1985g while ZDZ is 2000g, i.e. the weight difference is similar like
to the those 53g difference between OS.61FX and OS.91FX while the power output difference is lot more. At
least with many years on that comparrison I would not buy any .61 anymore - it is too havy for the power it
offers. Of course if you are assuming unstable RPM control over the ZDZ power then the choice goes to
MVVS-58. In my understanding anyway 125 g weight difference in a 10kg airplane is below the visible
difference, while 1bhp more is very visible, i.e we are talking about like 1% versus 10% difference.
Well I might be not compltely right if there is "hidden" weight associated with ZDZ, but I guess that
can be checked. Also another "social" argument is that ZDZ is better postioned for the further use
because I have not seen anyone who has big airplane and he is not talking about making bigger one,
it seems in this field, nothing is big enough and size of the ariplane is limited only by ... the size of the
car one can afford to transport it.
Cheers,
Nick

pe reivers

OK, The 43cc engine and DA50 are a bit too small for a 22 lbs plane. Remains the 58 and 80cc
forget the advertized horse numbers.
Does the ZDZ pull a 26x10 prop at 6100 rpm? The MVVS does.
If the ZDZ is stronger than that it will be one factor in your decision.

NikolayTT

Hi Fellows,

I have a Question to those who represent those engines here: - I fully understand that it is difficult to compare the
engines by the BHP which is given at certain RPM. Is it possible to get from the Manufacturers and/or Authorised
Representative the Measurements of the three(3) parameters RPM, BHP and Torque, or even Thurst in kg on
the ground test for reccomended low-pitch propeller which would be the best for vertical slow flight ? Of course
there is discussion on tachometry but that is not by the manufacturers and it is better those who make the
engines to tell what the design is good for. Unfortunately there isn't much data and only a list of several propellers
is reccomended. Related Question to this is also: - How much near to the max RPM one can come, and can we
exceed even them and with how much without damaging the engine ? I have done it and that engine did not
break "instantly" as some were suggesting, it was a gas engine of air-blower 28cc in price of 50 USD and
the max RPM were 9600; I went to 12800 on APC 17x6W propeller and there are no problems; i.e. what is
"wrong" with that engine ?! Of course I would not try that on expensive good engine. All those questions, if
well answered by real numbers would give us lot of things to consider and make most out of every engine
resources without spending too much time on tests and money on propelers . Please, provide such data
or a WWW-page where we can get it from; is that possible ?

Thanks in advance,
Nick

Jake Ruddy

My Feedback: (40)

I would not consider the DA 50 for this plane... sure there are several people putting a DA 50 on a pipe and doing it with OK results but you are adding weight to get a semi decent powered plane.

I have flown one many times with a 3W70 and it's a great combo.. so the 58 or zdz 80 is gonna be the on.

ZDZ 80 is gonna turn a 26x10 at 62-6500 depending which muffler you have.

Hard choice.. $200 is gonna get you a bit more power and be more usable down the road... depends what your future plans are.

rmh

power per pound ?
is that the question?
the non J ZDZ on pipe? the MVVS 58 on Pipe?
this discussion has more missing parts than an old Berkely kit.
for dead simple most power the ZDZ80 on a free flowing Pitts - easy setup and unless the others have had a miraculous infusion of muscle -- easily the top of the power game here. and heaviest--
for lightest setup and most power the MVVS on a full cf pipe SHOULD fill that bill
The DA50 even on a pipe - forget it
That kit -having dun em for others is too friggen heavy for it's size
nice model tho----
an old ZDZ60 on a full cf pipe is a good performer - it has same stroke as early ZDZ80 and on a long pipe a real performer. typical power band -smooth and throttlable is in the 6400+ rpm range on Menz S been there -dun it
I look at 20 lbs as tops for ANY engine of 60cc. My own stuff was kept around 18 lbs for the 60 -

Jake Ruddy

My Feedback: (40)

yeah.. I didn't think to say that the quoted mvvs58 is prob on a pipe... all those engines seem to always get quoted with pipe numbers. The numbers I quoted were with a pitts style muffler on the ZDZ RVJ

LowKey3D

Here is my dilemma. MVVS 58 or DA-50.

Plane weight 18lb 8oz with MVVS 58
same ARF with DA-50 and smoke 18lbs 9oz. I say I can save a 1lb without smoke..

I don't plan to running smoke but I want 3D performace with pull out.. No room for pipes..

I'm leaning towards to 58..

frieshoo

My Feedback: (20)

I would not consider the DA 50 for this plane... Maybe the new DA 85, when it's available.

I had a similar size ARF, A WM Extra 30% (90inch Wing 1500sq 19lbs)... and it was excellent with the Evolution 58 (Mvvs 58)...

However, I would think about down the road applications.... A ZDZ 80 (standard, or Super 80) is awesome on the Comp Arf 2.3's... I have never flown one, but have seen several in action...

The moving up factor:

With the new lighter 35% ARF's (some proto types are around 23lbs with a 3W80 and 1900sp in of wing = foamy) coming out of Asia, the ZDZ 80 seems to be the choice.

rmh

The heavier RVJ on in cowl runs 26x10's -at least the four I have setup - well into high 6000 to over 7000rpm on in cowl Pitts ( different brands vary all over the map). On full pipe- 27x10 in high 6000rpm. one runnin SOB.
On this model it just adds more weight tho - which is real problem with the model in question..

Jake Ruddy

My Feedback: (40)

ya I keep seeing numbers like that... but I have seen 2 of the early ones run with the same muffler here close to sea level on can only get 6400 out of them with a PT 26x10. I was beginning to think they got stamped wrong and were RVs instead Have one at a buddies house that isn't out of the boxyet.. have to see what it does.

BTerry

My Feedback: (8)

Both of our older ZDZ-80's spin the old-style Bambula 26x10 (very heavy load) in the 6500-6650 rpm range at 4350 ft. My Dad's DA-100 turns the same prop around 6800-6900 for reference.

The midrange characteristics of the MVVS and ZDZ are very similar: SMOOTH and controlled, without any hiccups, stumbling, or spitting.

BaldEagel

Have a look at the MVVS 58 Pro Sport it gives 8hp @ 6800rpm according to spec, I am running a 24x10 three blade on mine at 6,600rpm still running in.

Mike

pe reivers

The 58 reportedly and repeatedly runs 6100 - 6200 on a 26x10 Mejzlik prop and 3204 canister. This muffler has sacrificed top end power for a wide powerband response. Power and torque curves can be downloaded from my web pages if anyone cares to look at them instead of quoting the lack of them.
MVVS never had this engine running with a tuned pipe, but I did, and got 7500-7800 rpm with a 2-blade Mejzlik 24x10 and KS50 pipe, not tuned for best power yet. This equates to nearly 9 HP. This test earned me some grave looks from MVVS who never designed the engine for this kind of rpm.

aerobear

My Feedback: (4)

Is this with a Mejzlik 26x10 standard blade or the 26x10 narrow blade?

pe reivers

In the documentation, there is no mention of a narrow blade.

rmh

On your test --did you use the narrow blade 26x10?
As you know,
The loading differences in various brands/types 26x10's is wide.
The strange part --is that looking at the props you can't tll which is /is not the heaviest load
I have some ZM props which are very stiff /well made CF and the 22.25 x12 is very narrow but really loads the 50 engines - on the other hand -I have 22x8 MSC wood props which look like hockey sticks in shape and width - yet they rev like crazy. also, they are good 3 D props.

NikolayTT

Hi Fellows,

Why debating so much on this or that blade[sm=spinnyeyes.gif], it looks to me much better to
tell the max static thurst on the ground measured in kg and tell with which
propeller it was achived; is there anything simpler than that in order to
make those discussions really convincing for every one ? Of course
some might still disagree, but are there any universal reasons not
satisfied with that type of test and everyone who do not believe that
can test himself, isn't it ? Also the test is very realistic for power
torque, isn't it ?

Cheers,
Nick

BTerry

My Feedback: (8)

Nick,

I highly recommend you get a copy of Pe Reivers' EXCELLENT prop thrust calculator Excel program, it will give you a better benchmark on props. Static thrust means little to the overall flying characteristics of the plane, and props with high static thrust often have far less thrust at speed than other props with lower static thrust.

NikolayTT

Thanks BTerry,

Surely propeller for speed is not the best for power torque either; I guess all we use various
propellers depending the model and way to fly it. My only simple comparisson of the engine
Max-Power delivered in lfight and on the ground is the same only at power torque, or hoovering
above the ground, while for speed flying the results on static test are of less importance for
sure.

Yes, I went on that www-page of Pe Reivers'
http://www.mvvs.nl/prop-power-calculator.xls
and I am very happy with the table.XLS, they seems to match very nicely almost all the
measurements I have made for various engines from 2.5cc till 34cc; I just wander why then
in his reply on 4/4/2007 (here above) Pe Reivers wrote 'forget the advertized horse numbers',
did I misunderstand something ?

Anyway, the table is really great and the best I have so far; sincere thanks to Pe Reivers
for ptoviding it - it will save me a lot of time for tests !!!