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Cox Engine of The Month
.051 Venom!
Page 1 of 1
.051 Venom!
Parts from Bernie arrived........
I had my heart set on buying a Venom II, but I decided a red crankcase was all I really needed to make one with parts I had on hand. As luck would have it a couple .051 cylinder sets arrived at my door today as well. So......... I decided to be a little different and do an .051 version of a Venom.
I managed to get the piston weight down to 2.75g using the hobby knife/drill method and the rest is made up with the standard venom cloning parts. Tank/backplate, head and piston/cylinder are NOS Cox parts. I will tach it soon and see what I get.
I had my heart set on buying a Venom II, but I decided a red crankcase was all I really needed to make one with parts I had on hand. As luck would have it a couple .051 cylinder sets arrived at my door today as well. So......... I decided to be a little different and do an .051 version of a Venom.
I managed to get the piston weight down to 2.75g using the hobby knife/drill method and the rest is made up with the standard venom cloning parts. Tank/backplate, head and piston/cylinder are NOS Cox parts. I will tach it soon and see what I get.
Cribbs74- Moderator
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Posts : 11907
Join date : 2011-10-24
Age : 50
Location : Tuttle, OK
Re: .051 Venom!
Where are you finding these ,051 piston/cylinder sets?????
Engine looks good. Should be a runner with the lightned piston.
Engine looks good. Should be a runner with the lightned piston.
Jason_WI- Top Poster
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Posts : 3123
Join date : 2011-10-09
Age : 49
Location : Neenah, WI
Re: .051 Venom!
hey, i'm still waiting for you to spill your guts on your speed secrets, lol!!!!
p.s. made it to the post office today!
p.s. made it to the post office today!
Re: .051 Venom!
Mark Boesen wrote:hey, i'm still waiting for you to spill your guts on your speed secrets, lol!!!!
p.s. made it to the post office today!
Glad you did, I'm a dirtbag. Hopefully tomorrow. I'll shoot you a PM
Cribbs74- Moderator
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Posts : 11907
Join date : 2011-10-24
Age : 50
Location : Tuttle, OK
Re: .051 Venom!
Hopefully it will run as good as it looks!
I need to find the time to completely rebuild my Venom clone. It was perfect when I basically combined a 1990 Black Widow tank, SureStart case fitted with a DDD crank and a Killer Bee .049 cylinder and piston set. Bought a red case for it shortly afterwards and after a little bit of crank polishing it was back to the way it was before. A friend was going to be flying in some kind of micro RC winter competition a few years ago and he wanted my Killer Bee cylinder and piston set for his Black Widow, somehow he talked me into it and I let him use the set. Ever since then, it has never been the same, piston ball and socket was loose (and for some reason refused to reset) and the piston to cylinder fit was loosened. This was from a early Estes Killer Bee so the piston wasn't lightened, I have recently re-fit a new piston but haven't had the time to do much else. Between the time that the engine was "junk", I removed the 1990 Black Widow tank and tossed it back on its original Black Widow front end and bought a new stunt tank from Bernie for the clone. When I did the most recent test run last August, it peaked at about 5,000 RPM LOL! One of these days, I'll just have to sit down and put a bunch of work into it.
Can't wait to hear your results.
I need to find the time to completely rebuild my Venom clone. It was perfect when I basically combined a 1990 Black Widow tank, SureStart case fitted with a DDD crank and a Killer Bee .049 cylinder and piston set. Bought a red case for it shortly afterwards and after a little bit of crank polishing it was back to the way it was before. A friend was going to be flying in some kind of micro RC winter competition a few years ago and he wanted my Killer Bee cylinder and piston set for his Black Widow, somehow he talked me into it and I let him use the set. Ever since then, it has never been the same, piston ball and socket was loose (and for some reason refused to reset) and the piston to cylinder fit was loosened. This was from a early Estes Killer Bee so the piston wasn't lightened, I have recently re-fit a new piston but haven't had the time to do much else. Between the time that the engine was "junk", I removed the 1990 Black Widow tank and tossed it back on its original Black Widow front end and bought a new stunt tank from Bernie for the clone. When I did the most recent test run last August, it peaked at about 5,000 RPM LOL! One of these days, I'll just have to sit down and put a bunch of work into it.
Can't wait to hear your results.
Re: .051 Venom!
Jason_WI wrote:Where are you finding these ,051 piston/cylinder sets?????
Engine looks good. Should be a runner with the lightned piston.
I did a trade with Ebeneezer to help him fix his .010. They were really good used, but not new.
I hope it spins up, but to be honest I don't see it going much over 19K
Cribbs74- Moderator
-
Posts : 11907
Join date : 2011-10-24
Age : 50
Location : Tuttle, OK
Re: .051 Venom!
Admin wrote:Hopefully it will run as good as it looks!
I need to find the time to completely rebuild my Venom clone. It was perfect when I basically combined a 1990 Black Widow tank, SureStart case fitted with a DDD crank and a Killer Bee .049 cylinder and piston set. Bought a red case for it shortly afterwards and after a little bit of crank polishing it was back to the way it was before. A friend was going to be flying in some kind of micro RC winter competition a few years ago and he wanted my Killer Bee cylinder and piston set for his Black Widow, somehow he talked me into it and I let him use the set. Ever since then, it has never been the same, piston ball and socket was loose (and for some reason refused to reset) and the piston to cylinder fit was loosened. This was from a early Estes Killer Bee so the piston wasn't lightened, I have recently re-fit a new piston but haven't had the time to do much else. Between the time that the engine was "junk", I removed the 1990 Black Widow tank and tossed it back on its original Black Widow front end and bought a new stunt tank from Bernie for the clone. When I did the most recent test run last August, it peaked at about 5,000 RPM LOL! One of these days, I'll just have to sit down and put a bunch of work into it.
Can't wait to hear your results.
5K! Something is very wrong!
I'll post back with results soon.
Ron
Cribbs74- Moderator
-
Posts : 11907
Join date : 2011-10-24
Age : 50
Location : Tuttle, OK
Re: .051 Venom!
cribbs74 wrote:Admin wrote:Hopefully it will run as good as it looks!
I need to find the time to completely rebuild my Venom clone. It was perfect when I basically combined a 1990 Black Widow tank, SureStart case fitted with a DDD crank and a Killer Bee .049 cylinder and piston set. Bought a red case for it shortly afterwards and after a little bit of crank polishing it was back to the way it was before. A friend was going to be flying in some kind of micro RC winter competition a few years ago and he wanted my Killer Bee cylinder and piston set for his Black Widow, somehow he talked me into it and I let him use the set. Ever since then, it has never been the same, piston ball and socket was loose (and for some reason refused to reset) and the piston to cylinder fit was loosened. This was from a early Estes Killer Bee so the piston wasn't lightened, I have recently re-fit a new piston but haven't had the time to do much else. Between the time that the engine was "junk", I removed the 1990 Black Widow tank and tossed it back on its original Black Widow front end and bought a new stunt tank from Bernie for the clone. When I did the most recent test run last August, it peaked at about 5,000 RPM LOL! One of these days, I'll just have to sit down and put a bunch of work into it.
Can't wait to hear your results.
5K! Something is very wrong!
I'll post back with results soon.
Ron
Send that engine in for the slow race.
Jason_WI- Top Poster
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Posts : 3123
Join date : 2011-10-09
Age : 49
Location : Neenah, WI
Re: .051 Venom!
Now that was funny Jason, I about peed my pants and fell off the couch.
I bet the reed is tight Jacob.
I bet the reed is tight Jacob.
Cribbs74- Moderator
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Posts : 11907
Join date : 2011-10-24
Age : 50
Location : Tuttle, OK
Re: .051 Venom!
Mark Boesen wrote:hey, i'm still waiting for you to spill your guts on your speed secrets, lol!!!!
p.s. made it to the post office today!
Yep, spill the beans, what was in that Babe Bee!
crankbndr- Top Poster
- Posts : 3112
Join date : 2011-12-10
Location : Homestead FL
Re: .051 Venom!
crankbndr wrote:Mark Boesen wrote:hey, i'm still waiting for you to spill your guts on your speed secrets, lol!!!!
p.s. made it to the post office today!
Yep, spill the beans, what was in that Babe Bee!
To be honest I didn't do much out of the ordinary. The only thing I did outside of the Gibeault guide was go larger on the venturi and run a bee crank. Apart from a Bernie top end it was a Babe Bee.
Ron
Cribbs74- Moderator
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Posts : 11907
Join date : 2011-10-24
Age : 50
Location : Tuttle, OK
Re: .051 Venom!
I ran this engine a while back and never did a writeup. The reason was the result was a dismal failure. Probably bad karma from messing with Jacob
Anyway 15K is what I ended up with. The reason though is due to the engine being a shaker. I never have any luck with the KB cranks and the thick hubs. For some reason I get bad vibes when using that combo. This is not a knock at Bernie. I assume I must be doing something wrong.
I will mess with it again eventually. I was kind of upset and just ran it a few times, oiled it and put it back in the bin.
Ron
Anyway 15K is what I ended up with. The reason though is due to the engine being a shaker. I never have any luck with the KB cranks and the thick hubs. For some reason I get bad vibes when using that combo. This is not a knock at Bernie. I assume I must be doing something wrong.
I will mess with it again eventually. I was kind of upset and just ran it a few times, oiled it and put it back in the bin.
Ron
Cribbs74- Moderator
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Posts : 11907
Join date : 2011-10-24
Age : 50
Location : Tuttle, OK
Re: .051 Venom!
7yrs later. That’s how upset I was...
I installed a new crank and made sure the drive plate was perfectly square. That seemed to have solved the problem however, she ain’t no screamer. I tached 18,150. Plenty of room for improvement. Nothing has been massaged or anything. Used 35% nitro and Cox grey 5x3.
I installed a new crank and made sure the drive plate was perfectly square. That seemed to have solved the problem however, she ain’t no screamer. I tached 18,150. Plenty of room for improvement. Nothing has been massaged or anything. Used 35% nitro and Cox grey 5x3.
Cribbs74- Moderator
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Posts : 11907
Join date : 2011-10-24
Age : 50
Location : Tuttle, OK
Re: .051 Venom!
Just dont fix engine direct on the plank:no-no-no: use chim behind back plate fixation it wil let air coming inside its ventury just that litle Intake space just Good for baby bee and groove the wood pice behind for larger air gap it realy help just look at one es bee engine mount its Not flat wel Most cox engine mount use that chim space from the back plate To the engine mount just take look on them u wil Find wy the Venom wont performe Like he should and dont dril hole behind the ventury wil Not help wil just do restrictions on the air flow je wil go in wrong direction act like siphon and deflect air flow bit hard To explain
davidll1984- Diamond Member
- Posts : 2328
Join date : 2020-02-12
Age : 39
Location : shawinigan
Re: .051 Venom!
Y have one runing 22 k To 23 if place its cylinder Horizontally y was using the oem cox crank from baby bee Not the loose one no play at al spin free without résistance hd crank wit large drive plate Not Good for vibration y use oem pilot Bolt setup no vibration the one used wit the engine on that picturs nead longer Bolt it look like u change it alredy Good tink the chorter nose cone litle is Good way To get some vibration of try wit difrent Bolt if u have vibration in som of the custom engine modified using the tube Intake choke carb y use two trust wascher one larger one smaler one fit crank the other one behind the drive plate now it last longer Use less quickly y have lots one on m'y tigermoth after like 150 flight of 20 minute
davidll1984- Diamond Member
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Re: .051 Venom!
Thanks for the suggestions David.
22-23K means you should be a shoe in for a tach race.
22-23K means you should be a shoe in for a tach race.
Cribbs74- Moderator
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Posts : 11907
Join date : 2011-10-24
Age : 50
Location : Tuttle, OK
Re: .051 Venom!
I took a chisel and notched out the wood to improve airflow. I didn’t think it would have an affect, but I went from 18,150 to 18,540. So not much however, enough that I would consider it significant.
For my tach race engines, I will use the standard crank because of the rotational weight savings and yes it will increase performance. I am not concerned about tach race engines breaking if the crank lets go. It’s worth several hundred RPM if it stays intact.
For this engine, for all intents and purposes it’s an actual venom minus the crankcase and .051 cylinder. If I used an .049 cylinder it would be indistinguishable from the real thing. I don’t want it to break so it I will stay with the KB crank.
I have seen remarkable improvement opening up the venturi, 1,000RPM in some cases but again this one will stay stock BW sizing.
All that I can really do on this one is alter the fits and finishes. I could also change the prop and fuel too I suppose. I use the Cox grey 5x3 because it’s what’s always used as a standard when measuring performance.
What would be ideal is if I could machine the case for an oilite bushing!
For my tach race engines, I will use the standard crank because of the rotational weight savings and yes it will increase performance. I am not concerned about tach race engines breaking if the crank lets go. It’s worth several hundred RPM if it stays intact.
For this engine, for all intents and purposes it’s an actual venom minus the crankcase and .051 cylinder. If I used an .049 cylinder it would be indistinguishable from the real thing. I don’t want it to break so it I will stay with the KB crank.
I have seen remarkable improvement opening up the venturi, 1,000RPM in some cases but again this one will stay stock BW sizing.
All that I can really do on this one is alter the fits and finishes. I could also change the prop and fuel too I suppose. I use the Cox grey 5x3 because it’s what’s always used as a standard when measuring performance.
What would be ideal is if I could machine the case for an oilite bushing!
Cribbs74- Moderator
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Posts : 11907
Join date : 2011-10-24
Age : 50
Location : Tuttle, OK
davidll1984- Diamond Member
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Join date : 2020-02-12
Age : 39
Location : shawinigan
Re: .051 Venom!
Is lot more To consider if want To get that hi of rpm litle détail crank volume spi duration for ventury size Reed valve opening valve type like Cooper one the very thin one works Good for rpm gain its possible To modifs stainles valve
davidll1984- Diamond Member
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Join date : 2020-02-12
Age : 39
Location : shawinigan
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