Aruba

Hello,
I ran my zdz 50ng yesterday for the first time, I am using blenzall castor oil at 40:1 for the first gallon and then switching to Amsoil.
My initial rpms with a bambula 22-8 were 6400.
I'm using a peace keeper mufler.

Does this sound OK.

John

rmh

I can't hear it in Utah, so I guess the muffler is ok.
The rpm on a Bambula is -in every case I have tested, lower than any other brand.
This means that claims of " my 50 turns 7500 on "a" 22x8 means absolutely NOTHING.
Your results on that prop are good.
just follow good procedures in not running too lean or too rich.
The Bambulas unload well in the air but seldom if ever make the nasty "rip" .
If you plan on putting the engine in a heavy model - you may like a prop which spins higher.
On THAT prop and a clipped Bisson Pitts type. - we turn a bit more but on a 17.5 lb CAP 80" by H9, the performance is still excellent.
Going to other brands of 22x8 props the rpm go up a lot - as does the noise.

zonker123

My Feedback: (21)

thanks for the info, I had hoped to crank my ZDZ 50 up this week but too many other distractions.(maybe by the weekend) I have the Bambula 22-8 also but went and picked up a 22-8 pro zinger. I was hoping to find an APC 22-8 Wide but no luck so far (I do have the APC 20-8 wide but that may not be large enough) When you compare the Pro Zinger to the Bambula it is immediantly obvious that the Bambula should load the engine more, the cord on the Bambula is much wider along the last third of the blade than the Pro Zinger. The only way to tell if the lower rpm/ larger blade area of the Bambula works better than what should be a higher rpm reading with the lower blade area of the Pro Zinger will be have to be determined by flying.
Sounds like an excuse to head to the field.

take care
zonk

lenough

Dick,

You mention "clipped" Bison Pitts Muffler. How much did you cut off of the pipes and how much difference did it make? I am planning on using the same combo mentioned in the post. ZDZ 50 with a Bambula 22x8 and Bison Pitts Muffler on a CA Extra 27%.

Thanks,
Lee

vkmaynard

My Feedback: (1)

My ZDZ50NG got 6900 rpm on Mejzlic 22X10 on the second run (only bumped the throttle just to get the reading).

I Finally got to fly last weekend. After 10 flips to get the ZDZ50NG started the first time (had not run for months), all other starts where ONE flip. The 80" H9 has rediculous performance with this engine. Unlimited vertical at about half throttle. Normal take off and flying circuit with big loops at around 30% throttle. Still have not run the first gallon of break in gas through the engine.

Victor

rmh

the clip is not length critical-- it is simply to eliminate the rolled ends.
these reduce effective area by a huge amount .
On THAT prop -we got well over 200 rpm change
Funny tho - the clipped ends affect large prop loads more than ligher prop loads.
FWIW - on larger , heavier airframes ---do not increase prop size to increase power available - that does not work.
rather use a prop which operates in it's best efficiency range.
Last week we watched Brian try different Mejzlics on his (was mine) 35% Extra with the 100NG.
No tuned stuff - JMB mufflers.
The plane worked well on either prop but the smaller prop gave very noticably improved performance (either was very quiet).
Either hovered well but control was definately easier on the 26x10
My point being -you have to match the prop to the plane combo.
If I were to run the same engine/muffler in a smaller OR lighter plane - the difference in performance of the two props , would not have been as noticable.
How do I think that is so?
Tried it .
Our Giles (own design)- weighs 18+ lbs with either a 60 or 80 single .
speed USED for most flying is throttled back--either engine .
with the 80, we tried a bunch of props - 2/3 blade huge clubs ( cut down 12" pitch stuff - engine running in mid 5000 range etc..
The difference in performance --not much noticed with the various props .
the reason being that we were way over the top in power needed for anything on that size/weight airframe .
We had used that same engine in a 35% Extra at 26.5 lbs -on a tuned setup .
It worked tho not the greatest arrangement for Unlimited class ( we do compete)
it struggled along quite well. Prop selection did make a real difference there.
My point being that you have to match prop/exhaust/engine/model for best results

In your case, if the model is in the 17 lb range you should be just fine .
Ideally I would want a 15 lb setup - but again - That's my taste .
My 50 is going in a 1200 " sq in Dalotel - should be about 13 lbs.
(Last one was 10 lbs with a 1.4ST2300 on tuned setup and 30% nitro - great power but it swilled $15.00 worth of fuel in 6 flights.).
I will be using a tiny in cowl muffler I am testing (european design) that weighs --5 ozs.
It is not the most efficient but so far it really runs well and is quiet.
The weight is such that I won't notice power losses form the muffler.

zonker123

My Feedback: (21)

Ive got the supersonic pitts for mine, the fellows at R/C Showcase told me that it should be good for about 200-300 RPM increase over the Bisson pitts. Don't know about the noise yet. I've got an OS 160 with the bission that had the rolled tips, cut the tips off and saw a 200 rpm increase but the noise level came up a bit too, almost to the point of being irritating. put some 3" long pipe coupler material on the stacks, lowered the noise level to little less than the stock tips but only lost 100 RPM. I am leaving it like that,


zonk

Forgues Research

My Feedback: (7)

I don't think you should run your gas engine with castor oil, you should go with Penzoil 2 stroke oil before going with Amsoil Synthetic. But not Castor oil, that's a no no.

Roger

Aruba

Roger,
Can't find Penzoil for aircooled 2 strokes here. I can only find the ashless stuff, whitch if I'm not wrong is not suppsed to be used in these engines.
I asked RCS about it and they said to use it(castor) and then switch to synthetic.

John

CrowCreek

My Feedback: (15)

I cut the rolled ends off the down tubes on my zdz.50 RPM went from 6200 to 7000
This is the old 50 not the NG. Bambula 22-8
Not sure of muffler brand as I bought this engine used . approx. 4 gal. gas so for.
Tac used Hanger 9

rmh

The rolled end mufflers are the Bisson-
These are good at noise reduction .
The rolled ends restrict exit flow--and noise.
This design did not include an angle plate at exhaust port- (some engines don't like a flat reflector at the exhaust opening.)
I am testing two new designs (commercial) which include an angle plate,to change the flow at the exit- basically, the idea is to direct the flow.
One setup is on a NON NG version. We will fly it this weekend -weather permitting.
I ran the initial ZDZ50 version ,which on header systems ,ran very well.
I have seen comments that these engines were failures.
Not so. Just negative comments.
The original sleeve design was for tuned systems and free flowing systems
Adding the restrictive muffler caused performance to suffer when loaded into lower rpm ranges.
On a KS setup -they ran very well.
On better, in cowl setups - still very good performance.
These new mufflers should also work very well on the DA 50s which share the same exhaust mounting dimensions.

CrowCreek

My Feedback: (15)

I plan on putting this engine in a Godfrey 33% laser 200 scratch built.
I have a in fus. tuned muffler that fits my Webra Bulley. 2.375 dia/10.500 long.
How long should the header pipe for best preformance?
This plane with Bulley and same exhaust sysyem weighs 17.50 lbs.

With the ZDZ-50 it should weigh about 18-19lbs.

rmh

header length - I don't know - actually -you have to match rpm to tuning - and you could get a great or a very bad setup -
But -- on the early version of th 50 (not the NG)- you need a fair bit of header and I would suggest you start by propping using the 22x8 -in Mejzlic as well as the Bambula - the mejzlic will turn faster - which makes transion less cranky .
Your tuned pipe length does not tell me how the mfgr setup the "center of the pipe -
there are lots of different ideas on this and most do work--as long as you know where the tuning length of the chamber is located.
I will venture a guess that overall , your setup -from engine to end of pipe will be around 40"!
It could be shorter but if the pipe is anything like the KS pipes - -the tuning length for that engine will be at least 60cm
That is for good smooth power .
some canisters, simply don't tune very much nd they are half that length.
We are testing a new design incowl Pitts setup on a 1st gen 50 tomorrow -
On the 21x8 Mejzlic- the rpm on the ground is almost 7500.
This is nothing spectacular but it is better on thrust than setups which run --on THAT engine, at low 6000 range.
It just may be that this Pitts style unloads well - we will see.

zonker123

My Feedback: (21)

Finally got to get a tank thru my 50 NG, 6200 -6300 on bambula 22-8 in short bursts. I was a little heavy on the breakin oil though, about 30:1 with Merc Quicksilver. Altitude is aprrox. 200' ASL, temp 65 degrees, 100% humidity--it was raining at the field so we ran the engine under the shelter. Starting was fine once we hit the proper low end setting. ignition on, choke closed, high idle, flip till it pops, ---choke off, 5-6 flips, motors running. Hot starts were 5-6 flips. no choke. Should get better as the engine breaks in. Will mount the 22-8 pro zinger today and see what the RPM is. If the sun comes out might even fly the plane.

zonk

rsrogers

My Feedback: (10)

Dick, I see you have done quiet a bit of experimenting non the ZDZ's & props. I to am getting ready to put my new ZDZ 50NG to work & plan on using a Menz 22/8 for breaking in. Could you give me a little insite on this one. I had originaly planed on the Pro Zinger but since I need a rare size (17/8) for one of my smaller set-up's and Menz is the only wood manufacturer that I have found that has them in that particular size I thought I would give both sizes a try & maybe save a little shipping.

Thanks In Advance

Steve

rmh

MenzS 22x8 is a good match for the engine - The Bambula -same size turns much slower - just loads more .
I use the MenzS22x8 and the mejzlic 22x8 and th Bambula 22x8 -
big rpm spread .

rsrogers

My Feedback: (10)

Thanks alot Dick. Its going in a G.P. Patty Extra 300!!

JBrannon

My Feedback: (3)

Dick, What is a good prop for the ZDZ80 with the brison pitts muffler that had the ends clipped on a 22lb H9 Cap 232. I have tried the Bambula 26-10 and 26-8 getting 5600-5700 rpm and need more rpm. At 35-40 bucks a shot I could use some advice. Thanks,

Joe

rmh

The 26x8 is good on that muffler - usually - especially the newest Bambula 26x8 -if they have them at RCS.
Your readings are a bit low - but I can't see that many miles away -sooo I don't know why.
If engine is in good repair and you have a synthetic 32-1 --40 -1 mix -and all is working well - I would expect higher readings.
whatever you do - do NOT lean it to get highest rpm on the ground!
the engine should only peak under full load - --pointed straight up .
listen and adjust over a few flights - try for perhaps a bit of occasional level flight "four stroking" - but clean full power on uplines.
I run the 26x10 Mejzlic /26x10 Bambula -also - for a muffler - I am now pretty much sold on the very short header and the JMB 70and 80 mm cans.
for in cowl - I like the Supersonic -there are differences in all of these mufflers - although non are tuned setups - that's another ballgame .

zonker123

My Feedback: (21)

Got to fly the plane today (DP edge, 16LBS dry) 50ng is more than ample, changed break in fuel to 40:1. after 3 tanks, 6400 -6600rpm on the bambula 22-8, Prozinger 22-8 turned 7400- 7500 rpm------dont get too excited though--- the lower turning bambula had a LOT more vertical pull and was faster going straight up and in level fight than the higher turning zinger. The bambula was noticably better. Surpised me (pleasantly!)

zonk

Aruba

Hi,
My 50 ng is running good, the only problem I am having is starting, I think i don't have my procedure down yet. I have no problems starting my 80, bu the 50 is different.
Also the throttle is any thing but linear, how do you guys get a linear response, how do you set it up on the tx I'm using a Futaba 9c atv is set 100-100.


Thanks,

John

ml3456

Isn't the Bambula a true 22" diameter prop, where the Menz/3W design is 21.5" diameter? Does this explain the lower RPM with a Bambula?

Mark

rmh

It isin the blade design - -the newest Bambulas are shaped much like the MenzS
and they still load more than the MenzS

zonker123

My Feedback: (21)

My first start yesterday was : idle trim up to high, choke on. ignition on, took 12 flips before it popped, choke off. 6 flips, engine started.
After a couple of circuits, brought plane in to make some changes, restarted engine about 5 minutes after landing: no choke, idle trim to high, 5 flips, engine running. Couple more hot starts was same procedure. Flew another tank of fuel thru plane. Drained tank so that my helper (KRAZAC-RC-----thanks gerald!!!) could conduct some C/G tests. Didn't restart the engine for about an hour waiting out some rain showers. Filled the tank, choke on, idle to high, ignition on 3 (yes three) flips engine popped, choke off, 3 flips engine running. If this is a indication of the !QUOT!hard-starting characteristics!QUOT! some others have complained about ZDZ engines, i must be doing something wrong.

ARUBA
Have checked to be sure that you are pulling the magnet past the hall sensor fully when you prop the motor? I had a zenoah 38 that gave me fits starting until somebody pointed out to me that you had to have the prop in the proper position to pull all the magnets in the flywheel past the magneto on the compression stroke.

Zonk

Aruba

Zonk,

Never checked, but will, maybe that is my problem.


John