MVVS .49 Dieselized - It runs!
08-27-2005, 08:51 AM
#1
Senior Member
Thread Starter
MVVS .49 Dieselized - It runs!
I converted a well run, late model MVVS .49 to Diesel, using a head made by Andrew J. Coholic (AJC).
I exchanged the original 8 mm #3219 carburettor, for a 7 mm choke #3216 model.
This engine has about 60 total hours of run-time under its belt, but still has the ABC's typical TDC pinch.
As a glow model, with the MVVS tuned silencer, it spun a Bolly 11.5x6 Clubman prop at 13,600 RPM.
Initially, using fuel made with technical grade diethyl ether, I could not make this engine do anything but 'ping' very loudly.
It sounded like an old car, pulling uphill in top gear, with the ignition excessively advanced...
I changed to CP grade ether and now use 35% of it, with 38.5% kerosene, 25% BeNOL Castor oil and 1.5% MEKP (polyester hardener), as an ignition improver.
Initially, it sounded like it is pinging as before, but after I clamped down the compression bolt more, it stabilized.
It spins a 12.5X6 bolly prop at 10,300 RPM, which amounts to 1.04 HP, with the normal #3245 silencer.
This is less than what it made as a tuned glow engine, but with a Diesel, it is low noise, fuel economy and great low-end torque that we look for; not buzzy, high RPM HP.
After he took the measurements for this engine, AJC can now make MVVS .49 heads galore...
I exchanged the original 8 mm #3219 carburettor, for a 7 mm choke #3216 model.
This engine has about 60 total hours of run-time under its belt, but still has the ABC's typical TDC pinch.
As a glow model, with the MVVS tuned silencer, it spun a Bolly 11.5x6 Clubman prop at 13,600 RPM.
Initially, using fuel made with technical grade diethyl ether, I could not make this engine do anything but 'ping' very loudly.
It sounded like an old car, pulling uphill in top gear, with the ignition excessively advanced...
I changed to CP grade ether and now use 35% of it, with 38.5% kerosene, 25% BeNOL Castor oil and 1.5% MEKP (polyester hardener), as an ignition improver.
Initially, it sounded like it is pinging as before, but after I clamped down the compression bolt more, it stabilized.
It spins a 12.5X6 bolly prop at 10,300 RPM, which amounts to 1.04 HP, with the normal #3245 silencer.
This is less than what it made as a tuned glow engine, but with a Diesel, it is low noise, fuel economy and great low-end torque that we look for; not buzzy, high RPM HP.
After he took the measurements for this engine, AJC can now make MVVS .49 heads galore...
08-27-2005, 09:21 AM
#2
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RE: MVVS .49 Dieselized - It runs!
That's really good Dar, Bob Davis suggested that I try a 12x7 on my Irvine .53, your 12.5x6 is very close, what are you going to power with it? I don't have numbers for the 12x7 yet but I think Martin does. Thanks
08-27-2005, 09:42 AM
#3
Senior Member
Thread Starter
RE: MVVS .49 Dieselized - It runs!
Thank you, Dave.
Calculating again; 12.5x6 and 1.04 HP @ 10,300 RPM is really close to the glow model's 11.5x5 prop; 1.05 HP @ 12,300 RPM, also with the standard silencer.
Same power, 2,000 RPM lower. Doesn't this prove the whole point of Dieselizing?
Just think of it. A 10x6 APC whirring at 14,300 RPM (typical 15% nitro on an OS .46FX/AX) is just 1.04 HP.
I am not even mentioning fuel consumption...
Calculating again; 12.5x6 and 1.04 HP @ 10,300 RPM is really close to the glow model's 11.5x5 prop; 1.05 HP @ 12,300 RPM, also with the standard silencer.
Same power, 2,000 RPM lower. Doesn't this prove the whole point of Dieselizing?
Just think of it. A 10x6 APC whirring at 14,300 RPM (typical 15% nitro on an OS .46FX/AX) is just 1.04 HP.
I am not even mentioning fuel consumption...
08-27-2005, 09:48 AM
#4
Senior Member
Thread Starter
RE: MVVS .49 Dieselized - It runs!
Dave,
I will probably put it in the same 67" span, WM Worldstar 40, the muffled glow MVVS .49 engine is in now.
I expect lower flight speeds, but better vertical performance, as well as about 45 minutes at full throttle, on a the 380 cc tank.
I will probably put it in the same 67" span, WM Worldstar 40, the muffled glow MVVS .49 engine is in now.
I expect lower flight speeds, but better vertical performance, as well as about 45 minutes at full throttle, on a the 380 cc tank.
08-27-2005, 05:51 PM
#5
RE: MVVS .49 Dieselized - It runs!
Dar my irvine 53 apc 12x7 davis head davis, abc fuel, I know was over 10K do not remember exact #. Today I finally got up the
lazy bee with the tt 10 davis head and davis 1/2 fuel It was quite Gusty up to 20mph not lazy bee ideal conditions , up wind it went up like a rocket ,was up only a few minutes now that I have throws right, handles ok (had way too much first time) but rather than risk the plane
came around upwind and almost a harrier landing. The first flight was pretty wild last week Hobbsy called it the "Butterfly" but did get it down
ok. martin
lazy bee with the tt 10 davis head and davis 1/2 fuel It was quite Gusty up to 20mph not lazy bee ideal conditions , up wind it went up like a rocket ,was up only a few minutes now that I have throws right, handles ok (had way too much first time) but rather than risk the plane
came around upwind and almost a harrier landing. The first flight was pretty wild last week Hobbsy called it the "Butterfly" but did get it down
ok. martin
