Quick test on tuned pipe ZDZ 50 RV
09-20-2005, 12:58 PM
#1
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Quick test on tuned pipe ZDZ 50 RV
This morning I expended some time on a quick experiment to test the AMT pipe
with my ZDZ 50 RV.
The thing went up to 7400 rpm 22X8 Mejzlik. While it barely makes 6900 rpm with the
supersonic muffler. Maybe the DA 50 or the ZDZ 50 NG can do this without tuned
pipe. Any inputs here?
I did not have time to tune the needles and the pipe length header, no sure
how much more I am going to get or maybe I already reached the ceiling of
the performance of this engine. BTW his is the first time I ever put tuned
pipes on my engines. As Dick mentioned, here is an additional heat generated on the head
cylinder, I guess nothing is for free.
However sounds promising to me.
How much more rpm would it be if with a KS pipe?
with my ZDZ 50 RV.
The thing went up to 7400 rpm 22X8 Mejzlik. While it barely makes 6900 rpm with the
supersonic muffler. Maybe the DA 50 or the ZDZ 50 NG can do this without tuned
pipe. Any inputs here?
I did not have time to tune the needles and the pipe length header, no sure
how much more I am going to get or maybe I already reached the ceiling of
the performance of this engine. BTW his is the first time I ever put tuned
pipes on my engines. As Dick mentioned, here is an additional heat generated on the head
cylinder, I guess nothing is for free.
However sounds promising to me.
How much more rpm would it be if with a KS pipe?
09-20-2005, 01:17 PM
#2
RE: Quick test on tuned pipe ZDZ 50 RV
Likely--less rpm with the KS--and depends on which KS
At least that is what I found
The AMT pipes Ihave tested , run harder than KS in each instance tried
Your header and pipe look exactly like my setup on my YAK tho I made my own header -
My 50NG ran 7750 on that setup when I used the Mejzlic 22x8
The 23x8 is also very good -running in low 7000 range.
Frankly I don't think you can beat the performance gain with the AMT pipes
I have also tried the larger KS pipe on my Super 80 - good but not as good as with the AMT80
The AMT is a bit heavier -but does not dent when you squeeze it with your fingers .
At least that is what I found
The AMT pipes Ihave tested , run harder than KS in each instance tried
Your header and pipe look exactly like my setup on my YAK tho I made my own header -
My 50NG ran 7750 on that setup when I used the Mejzlic 22x8
The 23x8 is also very good -running in low 7000 range.
Frankly I don't think you can beat the performance gain with the AMT pipes
I have also tried the larger KS pipe on my Super 80 - good but not as good as with the AMT80
The AMT is a bit heavier -but does not dent when you squeeze it with your fingers .
09-20-2005, 01:54 PM
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RE: Quick test on tuned pipe ZDZ 50 RV
The AMT is a bit heavier -but does not dent when you squeeze it with your fingers .
Can my 50 RV make 7750 rpm with a Mejzlik 22X8 on AMT 50 pipe?
I guess my question what would be the more I can get form my 50 RV on tuned pipe such as the ATM
09-20-2005, 03:16 PM
#5
RE: Quick test on tuned pipe ZDZ 50 RV
Not knowing your fuel/ignition etc., I would simply run it as it is - adjust carb such that it is on rich side for in flight - the RV engine unloads in the air - so if it is lean -it will not "unload " as it should.
We tried this a few times on our original RV 50 -I thought it was a good engine -then saw the grumblings about "poor power" etc.
When I duplicated the "poor power setups "- I also got poor power.
Running that engine on Bambula 22x8 and a stock Bisson -mine ran 5500.
changing mufflers and going to Mejzlic - it bounced right to life.
The engine has exhaust timing of 170 degrees - great for pipe - not the best for choked down, in cowl mufflers .
I doubt you will see any DA50 /ZDZNG or any 50 running without tuned setup of some kind going over 7400 on that prop.
I run direct reading tach -so I don't get wild readings from prop reflections .
Do not shorten the pipe header ! if the engine hesitates a bit coming up from 3000 rpm- -no matter how you adjust the carb needles - add about 2" to the header -just to see .
My guess is that you are pretty close to right as it is -just let it seat in a bit .
We tried this a few times on our original RV 50 -I thought it was a good engine -then saw the grumblings about "poor power" etc.
When I duplicated the "poor power setups "- I also got poor power.
Running that engine on Bambula 22x8 and a stock Bisson -mine ran 5500.
changing mufflers and going to Mejzlic - it bounced right to life.
The engine has exhaust timing of 170 degrees - great for pipe - not the best for choked down, in cowl mufflers .
I doubt you will see any DA50 /ZDZNG or any 50 running without tuned setup of some kind going over 7400 on that prop.
I run direct reading tach -so I don't get wild readings from prop reflections .
Do not shorten the pipe header ! if the engine hesitates a bit coming up from 3000 rpm- -no matter how you adjust the carb needles - add about 2" to the header -just to see .
My guess is that you are pretty close to right as it is -just let it seat in a bit .
09-21-2005, 12:28 AM
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RE: Quick test on tuned pipe ZDZ 50 RV
As far as needle settings goes, it sounds like I was close to the optimal settings.
I did not have to do a lot to obtain these rpms.
I was running the RV with the Supersonic muffler on the reach side. So I only leaned the high a little bit maybe less than an 1/8. I did not touch the low needle.
During the very short period of time that I tested the engine I noticed no problem whatsoever during the transition. The header length is right for this application.
Dick have a question for you: If I go with a 50 NG, can the same header length be used ? and perhaps reproduce or at least be closer to the 7750 rpm range ?
What I ma trying to find out is if it is worth to invest on a 50NG and use my RV for other project or use it as a back up engine.
(Using for this test Amsoil premixed 100:1 mixed 50:1 with 97 Octane gas)
09-21-2005, 06:23 AM
#7
RE: Quick test on tuned pipe ZDZ 50 RV
Work on the needle settings---- go back n forth on the low needle til you get a feel for best response - -if the engine gasps for fuel -cold - trying to come off idle yet is very positive once it warms up -it is about right.. lean the low speed till you get too lean- then back it out a little. The high speed -leave a bit rich.
As for looking for more power on same pipe - yes- the NG will turn more . How much? I don't know.probably 300 give or take -on same prop/ pipe as you are using.
Depending on your model and how you fly it - that may/may not make much difference to you
The fuel mix - to each his own - I run Mobil 1 -at 32 -1 that's it .
Your choice won't make near as much difference as your getting the needles set correctly.
As for looking for more power on same pipe - yes- the NG will turn more . How much? I don't know.probably 300 give or take -on same prop/ pipe as you are using.
Depending on your model and how you fly it - that may/may not make much difference to you
The fuel mix - to each his own - I run Mobil 1 -at 32 -1 that's it .
Your choice won't make near as much difference as your getting the needles set correctly.
09-21-2005, 08:08 AM
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RE: Quick test on tuned pipe ZDZ 50 RV
The next step is to engineer the actual mounting system.
If I want to install this device on my CAP 232, then I need to face couple of problems:
1) Assuming that I install exactly the same header, then the in-fuselage installation is out of the picture. Is more complex, need to build a tunnel for the pipe, adds more weight to the plane, the wing tube is on the way of the pipe plus the landing gear. (see the attached pictures for more details)
2) Building a channel underneath the fuse will be the one option, I want to avoid the ugly looking of the pipe sticking out underneath the belly. However I still need to clear out a way for the pipe through the LG. Probably I need to split the LG. I think that a side mounting will work better than an inverted engine mounting.
The 2nd option will require to customize my own header by using a longer drop and/or may be more than one 90 degree turn, while maintaining the length of the header that I got from RC showcase.
And this takes me to next question:
In a tunned pipe system, adding any additional 90 turns will affect the back pressure over the head cylinder, am I right? Therefore this will affect the tuned pipe system, so that a new header/pipe length needs to be figured out due to the new header configuration?
If I want to install this device on my CAP 232, then I need to face couple of problems:
1) Assuming that I install exactly the same header, then the in-fuselage installation is out of the picture. Is more complex, need to build a tunnel for the pipe, adds more weight to the plane, the wing tube is on the way of the pipe plus the landing gear. (see the attached pictures for more details)
2) Building a channel underneath the fuse will be the one option, I want to avoid the ugly looking of the pipe sticking out underneath the belly. However I still need to clear out a way for the pipe through the LG. Probably I need to split the LG. I think that a side mounting will work better than an inverted engine mounting.
The 2nd option will require to customize my own header by using a longer drop and/or may be more than one 90 degree turn, while maintaining the length of the header that I got from RC showcase.
And this takes me to next question:
In a tunned pipe system, adding any additional 90 turns will affect the back pressure over the head cylinder, am I right? Therefore this will affect the tuned pipe system, so that a new header/pipe length needs to be figured out due to the new header configuration?
09-21-2005, 08:25 AM
#9
RE: Quick test on tuned pipe ZDZ 50 RV
Mount the engine inverted - split the gear and make a "bridge" over the header -to tie the gear halves together - make a 1/2 deep tunnel from firm 1/16" thk balsa -I did this on H9 CAP with ZDZ80.
the length is what is important on header - the turns made with that tubing do not add restriction as they are quite generous radius.
cut and rebraze header to get necessary drop
The landing gear bridge , is a thinner aluminum plate (plywood could work) which is attached to inner ends of each gear thru vertical standoffs. Depending on your setup -the bridge could go over or under the header.
The idea is to simply tie the legs such that pulling /pushing sideways on th gear - the load is applied across to the other side.
I have done a number of these for pipe/can tunnels . You can't se th pipes unles you look under th plane and they don't show up in the air
the length is what is important on header - the turns made with that tubing do not add restriction as they are quite generous radius.
cut and rebraze header to get necessary drop
The landing gear bridge , is a thinner aluminum plate (plywood could work) which is attached to inner ends of each gear thru vertical standoffs. Depending on your setup -the bridge could go over or under the header.
The idea is to simply tie the legs such that pulling /pushing sideways on th gear - the load is applied across to the other side.
I have done a number of these for pipe/can tunnels . You can't se th pipes unles you look under th plane and they don't show up in the air
