Flyin Woodbutcher

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Dream , maybe for you.

EL TEMUCANO

YES MAYBE FOR ME,,, I DON´T WHANT TO OFFEND YOU,,,,,, MAYBE I HAVE THE MECHANIC IGNITION TIME WRONG OR THE CARBURATION IS BAD,,,,,, IF YOU CAN TELL ME HOW I CAN CHECK IT I´M GRATEFULL WITH YOU. I´M USING A 20/10 MENZ .

Flyin Woodbutcher

My Feedback: (3)

The tuned pipe helps . Also good and broke in.

Kent

EL TEMUCANO

THATS RIGHT,,,, I´M USING STANDART PITTS MUFLER....

Maudib

My Feedback: (51)

Quit it guys...

When the weather here breaks I'll take video of a DA50 with a MSC 22x8 and NX 23x8 spinngin 7500 and 7150 respectively tached with two different brand tachs...

No pipe, just stock muffler in Central Ohio... these are richened back about 100 rpm from peak... just broke in.

Flyin Woodbutcher

My Feedback: (3)

you dont have to convince me I know what the DA fiddy will do. Mine is so worn out from 3 years of use when it cuts off the prop free wheels all the way to the landing. Still on the DA muffler it will spin a 22x10 at 7350.

Kent

BTW my DA 100 and 150 run just as good, just waiting on the 75cc to put in the stable.

famousdave

My Feedback: (61)

Unless you are trying to power a Comp-Arf 2.3 or heavy pig don't worry about the RPM. This engine will produce enough power on a stock muffler to haul a 16 pound plane into space. Tune the engine by ear to the max RPM, back off about 200 and forget about it!

Slimline pitts muffler - excellent power, not too loud, easy to tune

DA Muffler- a little more power, louder, fairly easy to tune

1/4 wave pipes (KS, etc) - quite a bit more power, harder to tune (requires moving pipe in and out to find the node) needle settings are more critical too (easy to overheat)


The DA50 has more power than you will probably ever need ... I am not sure why so many people get hung up on getting every last RPM out of it.


The best props to use on this engine are a Menz or Bolly Wood 22x8, Mejzlik CF 23x8 or NX Wood 23x8 Don't use a 22x10 - too much prop.
If you don't believe me on the RPM or the props.. call DA.. that's right from the horse's (er, Brian and Dave's) mouth...

Also - the "carb mod" made no difference in the RPM, if there is a diff its probably due to the needles still being too rich. DA's run best leaned out on the low end and just under peak on the high end. The carb mod was made to prevent fuel from pooling in the reeds during idle (resulting in dead sticks) it had nothing to do with WOT performance.


I never tach my engines, total waste of time. If my engine starts great, has excellent idle transition, top end, runs cool and takes the plane straight up out of sight... who the %^%$ cares what the RPM is.... !

DP

Maudib

My Feedback: (51)

I care about RPMs and I think it's a little harsh to insinuate people are wasting their time "getting hung up" on RPM's. After all it the common denominator in thrust comparison.

400 rpm is a great deal of RPM... and thrust. Don't think so? Throttle trim your servo down about 400 rpm and enjoy the loss. It's the latest craze...

The poster asked about rpm's cause he wanted to know where he stands and where he might stand with another exhaust and prop. Sounds like he wants to maximize his power on his airframe... How silly huh?

Come on DP... your post had some good info but sure was "fatherly". You in a bad mood today?

ljones5000

My Feedback: (2)

I think DesertPig makes a good point; after a point the "quest" for the most rpm becomes no more than a bank-walking contest.

Maudib

My Feedback: (51)

Too funny... well now that you and DP know all the info YOU need... I suppose everyone else can go walk the bank?

Remember... just because YOUR quest is over... doesn't mean someone else isn't starting up theirs for the first time.

I know what combinations I like and have settled on, but I also like to share with people wanting to learn. Not just say "Take my word for it... do this and your golden."

I doubt you or DP wanted someone to rig your plane for you, but asked, tested, learned to get to your point of 50cc mastery.

While DP says not to worry about such things, I note he is fully aware of what muffler/pipe will give what performance hit/bump and the benefits/caveats of them. I aslo noted he is aware that the carb mod dodn't increase RPM... how would he know if he didn't measure or care? If he weren't at some point interested in getting best performance, why is he knowledgable about such things now?

Because he liked it and at one point early on had different motivations. Now that he has gained a considerable amount of knowledge, he doesn't NEED to worry about these things because he already KNOWS what is best for him.

Not knocking him at all... DP's a fav poster of mine and very knowledgable... but sometimes we forget that we have journeyed a ways to get that knowledge... and people (for the most part) are asking that we impart our knowledge, not prescribe.

In this particular case, we DON'T know what the guy has for a plane and it may VERY well be an 18 lber that he's seeking to egt the MOST from his engine. In which case DP just dismissed him unintentionally.

I'm just saying... hey if you don't care about learning about varying porps, rpms and making sure you are getting adeqate to maximized performance from your setups... then by all means walk on by the thread... but it was a little rude and insinuate that peopl ewho ARE interested in such things are wasting their time. It's presumptuous to think the RC world should be held to a particular person's viewpoint.

Anyways... I digress... DP... Gooddinfo, and really you were right on... I was just put off a little on how it came across. I've seen guys go away angry because they felt they were asking pertinent questions and felt like they were told they were idiots for worrying about such things.

krayzc-RCU

My Feedback: (31)

i think i will try a 22 x 10 on my OS-70 stay tuned for the numbers

Nogyro

My Feedback: (10)

FWIW, my DA50 on stock muffler turns a Mejzlik 22x10 at 7200. IMO that's not too much of a load..........

famousdave

My Feedback: (61)

Points taken guys... no harsh critism meant.. but my point is that I see a lot of NEW gasser guys get hung up on RPMS when in reality they should be paying much more attention to how the engine actually sounds, runs and flies the airplane. With gas r/c engines RPM is far less important than it is with glow - as most of our gas planes are significantly overpowered a few more or less RPM really won't be noticed (that is if you build light airplanes) .. It is not always best to get the absolute last eon of power out of an engine either - some times you want to run it less than full bore - means stuff lasts longer. In the racing world we call this detuning. A racing marine engine might last 15 hours max... the detuned version will last 250 hours... big diff.

As far as power, thrust and RPM - In reality the only true way to determine the real power output of any engine is to measure its output on a dynomometer under a real world load. A prop spinning on the ground (i.e. static thrust) does not really do much to estimate the true thrust ratio or power output of an engine... it also is not the best thing for an engine.

So to recap - yes, I am no stranger to RPM... you can bet in the racing world I pay very close attention to it... however when it comes to my hobby engine, if its running the right temp, has a good idle, transition, and can put my plane out of sight.... do I really care if I am not getting every last RPM out of it .... probably not. I would also argue that the best tuning point for any r/c engine (with the exception of racing) is one that is a compromise of idle, transition and WOT performance... often tuning for max RPM shunts the performance of midrange and idle. 'Nuff said.


Nogyro - you might want to use an inline tach (i.e. inserted at the hall effect sensor connector). My guess is your reading is off. The DA50 on a 1/4 wave pipe and performance PORTING did not spin a 22x10 at 7200 RPM, somehow I don't think that $20 glowbee tach is quite telling the truth....


Just adding a little color to the commentary that 's all!
DP

rcflyer96

Wow guys thanks for all the info. I had one flight on the 22 10, then switched to a 22 8. Made it a bit better but i'm going to get a Biela 23 8, and try to get ahold of a stock muffler. I wanted a bit more power... hopefully a few hundred more RPM will help.

As far as tach's go. I've been flying for about 3-4 years and have never owned a tach until a couple weeks ago. Mainly to see what numbers this engine would turn. I'm hopefull that I might gain even a bit more power.

Thanks again guys.

Nogyro

My Feedback: (10)

Not a glowbee, it's the other Tower digtial tach. Buddies read the same.......

Maudib

My Feedback: (51)

I agree with you wholeheartedly now... somehow I did't take the same inference away fromthe first post...

Until they make an accurate dynomometer for under $25 I think that RPM comparisons with the same prop is the most feasible method available. But then again you do have variances in tachs which account for error.

I don't mind the colorful posts... unless they seem to have a little too much black and blue in them...

Moving on...

Maudib

My Feedback: (51)

I think you are on the right track...

A prop can make a world of difference... and sometimes it's NOT because RPM goes up. Larger props can spin a few hundred rpm lower and still put out more thrust, or USABLE thrust based on your flying style/preference.

I had a 22x8 MSC on most of my 50ccplanes... great prop... tried an NX 23x8 on the YAK and LOVED it... tried it on a Vision 3D and didn't care for it as much.

Prop design has a bunch to do with it too... narrow blades, wide blades, thick/thin blades, sharp tips, blunt tips...

Just overall sometimes you can feel a big difference in the air just from switching brands and staying the same size... You'll find a brand/size you like the most and seems generally the "best", but then if you don't try others, you may not find that perfect prop that that particular airframe.

I am sarting to build up a selection of props and will continue to add to them.

I'll start with my trusted 22x8 MSC and get accustomed to the plane... then start experimenting with various props.

I do think you'll see a dramatic difference with a stock muffler...

Nogyro

My Feedback: (10)

I couldn't agree more......

I've got about 5 different props I've tried on my DA50 and G62 WH planes. Each one has different characteristics. RPM numbers really don't matter that much, it's all in how the plane performs........ and what I like, you may not.........

Some of the higher reving props are good in one area of flight, but may suffer in another.

I've got a 22x10 in the Mejzlik and Menz S brands. Those two props are as different as night and day on a DA50 WH Edge or Extra. Does that make one brand better than the other? No way.........just different.

It's just amazing how much different the plane will handle when you try different brands and sizes of props on it......The trick is finding the one you like.

Are my rpm numbers accurate? Don't know........all I use them for is comparing prop loads between different props, and it works fine for that.

famousdave

My Feedback: (61)

Nogyro - you hit it on the head - as long as the numbers do for you what you want them to - its all good. Its when people start comparing numbers and saying their engine does things the factory has not even seen is when things get fishy. These cheapo tachs are really only accurate to within 5% ... at 10000 RPM that can mean as much as +/- 500 RPM.. I have seen them be 10% off.

On the other hand - as long users only use them as a tool for general tuning their specific setups and not get too hung up on comparing them with everyone else... it makes sense. I gave up using them a long time ago because I can hear and feel the difference immediately betweeen props and needle settings.... yes, that took some time and experience but its not difficult.

A far more valuable tool than the tach is a thermocouple temperature probe... tune the engine by temp, and not RPM will provide a much better result and most likely lead to a longer engine life.

There is no doubt that different props act differently, even on different cowl designs.. no matter what the tach says on the ground though you really never know until you fly!


DP

rmh

The new ignitions with onboard recorders really put an end to the speculation -
On most - you can read rpm as you setup the prop and engine - then read the inflight rpm after landing .
This really fills you in on what power you are making -in your flight situation
fo example -if all you do is take off and hover around like a hawk over a mouse - you want the engine revving easily ready to leap in a instant -
If you do a little of everything - prop up a bit more - if you keep cruisin all the time run a prop that allows lower rpm for mor speed - you get the picture .
Example :
for the 3D stuff which really stays at high angles of attck - I prop my engine ( it is not a DA50) for at least 7500 on the ground and over 8000 in the air . ( 22x8 mejzlic)
For quieter performance - add more prop - for quiet really good IMAC-- a prop that is running 6700 on the ground and 7600 in the air . 23x8/ wider thicker 22x8/22x10 etc..
I can't seem to hurt my engines letting em rev - and the setups I use permit that - others setups may not tolerate this -
case -by case.
In air performance is the objective -of course -If your setup satisfies you - objective achieved-
Tho I prop my 50 for numbers noted - -I prop my Evolution 26 - for up to and over 10000-in the air - again- no problems .
It is surprising to find how high, actual in flight numbers are on some setups

Maudib

My Feedback: (51)

That's a truly nice feature of some of the ignition brands out there... very nice... that's an area I hope to see DA improve upon... a 4.8 - 9 volt acceptance and an onboard tach.

ljones5000

My Feedback: (2)

Dick Hanson---The idea of onboard tach reading thru the ignition system intrigues me...I wonder if that is availble through CH ignitions (all I have)? I guess I could call them and ask, but do you know? It sure seems that would be far superior to any other tach/method I have heard about.

Larry

rmh

yeh-- ZDZ/ Evolution (some models) /3W/MVVS/ ROTO and I think- the newer Falkons used by BME may (?) include this feature -
It is rapidly becoming a std --I can't imagine that DA has not already looked hard at this - they have a ZDZ80 and a 3W 80 for lookeesee- - everyone in the business looks at others stuff - unless they are just plain clueless--.
Everyone still has their own ideas as to how to do it --
so far - the setups go like this :
3W - mount an onboard 3W tach display -also a LED flashes on full voltage power up
Falkon -read at the switch -SOME models
Roto/Evolution (some models)- LED flashes on full voltage power up - read LED with optical tach as desired plus read saved max rpm at LED
ZDZ- plug ZDZ tach into ignition switch - read direct in rpm or as a bar graph- read saved max rpm
It would be nice to have a standard for all of this but still too early - everyone is not in the game and each want to feature (sell) their own idea.
Way back when-- American cars had different shift arrangements on automatics - PNDLR and PRNDL- after some problems - one pattern was agreed upon . a standard tach readout ignition is also likely to evolve --

famousdave

My Feedback: (61)

3W's come with this feature.. unfortunately they are charging $100 for a $10 tach...

DP

Nogyro

My Feedback: (10)

Dick H..........that was a great summation of how to prop an engine depending on what style of flying you enjoy doing. It's just a matter of trial and error to match the airframe/engine with the prop that suits your needs.

As far as tach's go, I'm like DP and don't use one to tune my engines. Start both needles out at 1 1/2 to 2 turns and go from there. I like to get the low needle set to where I have a reliable idle, good transition, hopefully not much blubber in the midrange, and no sag on full throttle vertical runs. Pull the plug and make sure it's a nice tan and you're good to go.