Echo 650 update, and finally
04-16-2010 | 09:35 PM
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From: Salinas,
CA
Echo 650 update, and finally
I got the bigger carb today. HDA 137. I opened up the intake manifold to match the new larger carb. The venturi on this one is 16.61mm. Before I was running a WT-542 (13.49mm). I had little time tonight to mess with it. Before I was getting:
Bambula 22x8 7200 rpm It pulls 21-pounds on a spring scale tied to the tail
TBM 21x8 6800 rpm 23-pounds
top flight 20x10 20-pounds
Now it is spinning a MENS 22x10 at 6700
and a Vess 22A at 7000
The MENS calculates to #30 thrust, ...that would be more! nice
.
I'll play more and see how it goes. I need to try the old props and see a direct comparison. I just grabbed the closest ones tonight.
Saturday AM:
Mens 22x10 6600 27#
TBM 21x8 7000 24#
BAM 21x8 7450 24#
BAM 22x8 7500 26# (must have been carb setting changed?)
MENS 24x10 5600 28#
For fun I tried my CS-510 conversion with a WT-542 carb, MENS 22x10, 6200.
On the 650... the larger carb does not idle as smoothly as the wt-542. I can not get it to run well below 1800 rpm. That means the plane will roll at low throttle. It seems to have the rich mid throttle issue. If I set the high speed to peak then chase the burble down wiht the low speed needle, I end up lean at the low end. Isn't there something about filing a notch in the butterfly to help that? I am not sure it is worth the bother, I only gained 300 RPM with this exersize.
Later Saturday, BBQing some pork and drinking beer. Why not fuss around in the shop? I made an exhaust with two 1" pipes. Free flowing exhaust is crazy loud! It now spins a Bambua 22x8 at 8000. That is 6.6 hp and 41 pounds of static thrust. It 's almost like a big boy engine. So, I have gained 800 rpm over where I started.
I will fly it tomorow.
Bambula 22x8 7200 rpm It pulls 21-pounds on a spring scale tied to the tail
TBM 21x8 6800 rpm 23-pounds
top flight 20x10 20-pounds
Now it is spinning a MENS 22x10 at 6700
and a Vess 22A at 7000
The MENS calculates to #30 thrust, ...that would be more! nice
. I'll play more and see how it goes. I need to try the old props and see a direct comparison. I just grabbed the closest ones tonight.
Saturday AM:
Mens 22x10 6600 27#
TBM 21x8 7000 24#
BAM 21x8 7450 24#
BAM 22x8 7500 26# (must have been carb setting changed?)
MENS 24x10 5600 28#
For fun I tried my CS-510 conversion with a WT-542 carb, MENS 22x10, 6200.
On the 650... the larger carb does not idle as smoothly as the wt-542. I can not get it to run well below 1800 rpm. That means the plane will roll at low throttle. It seems to have the rich mid throttle issue. If I set the high speed to peak then chase the burble down wiht the low speed needle, I end up lean at the low end. Isn't there something about filing a notch in the butterfly to help that? I am not sure it is worth the bother, I only gained 300 RPM with this exersize.
Later Saturday, BBQing some pork and drinking beer. Why not fuss around in the shop? I made an exhaust with two 1" pipes. Free flowing exhaust is crazy loud! It now spins a Bambua 22x8 at 8000. That is 6.6 hp and 41 pounds of static thrust. It 's almost like a big boy engine. So, I have gained 800 rpm over where I started.
I will fly it tomorow.
04-20-2010 | 10:09 PM
#2
RE: Echo 650 update, and finally
The larger carb will flow more fuel at high RPM, but you're seeing the effects of over carburetion at low RPM. Can't lean it enough to smooth it out because it just dumps too much fuel. If you lower the RPM it just dies from flooding.
Put the smaller carb back on it.
It won't have the same top end, but it'll idle and transition cleaner.
EDIT:
Could be an air leak?
Put the smaller carb back on it.
It won't have the same top end, but it'll idle and transition cleaner.EDIT:
Could be an air leak?
