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Cox Engine of The Month
July-2024
robot797's
"ULTIMITE COX 010: it has a clutch, E starter, throttle, exhaust, aluminum tank, aluminum venturi, gearbox with forward and reverse, and now its on a custom drawn and printed stand"
PAST WINNERS
robot797's
"ULTIMITE COX 010: it has a clutch, E starter, throttle, exhaust, aluminum tank, aluminum venturi, gearbox with forward and reverse, and now its on a custom drawn and printed stand"
PAST WINNERS
Big Brother - Round one
Page 1 of 1
Big Brother - Round one
Hitched up a coat hangar trial bridle.
Made a CG finder out of a dowel, piece of string, and a clip
Perfect CG
Not so perfect CG
No matter we are going to crank this thing up and see what happens. I had bench tested all three Golden Bees last week, and all ran very well. Not today, nose GB would not start past the prime. Swapped out with the right side GB that started right off. Plan is to do a circle with just the nose engine running then add the other two.
Didn't happen, went hard right against the tether line. Got adjusting to do.
Mark came up with a good idea. Bend the bridle as shown with two interior wheel collars and adjust inward until the sweet spot is found. Saves a lot of bending and trial and error.
Made a CG finder out of a dowel, piece of string, and a clip
Perfect CG
Not so perfect CG
No matter we are going to crank this thing up and see what happens. I had bench tested all three Golden Bees last week, and all ran very well. Not today, nose GB would not start past the prime. Swapped out with the right side GB that started right off. Plan is to do a circle with just the nose engine running then add the other two.
Didn't happen, went hard right against the tether line. Got adjusting to do.
Mark came up with a good idea. Bend the bridle as shown with two interior wheel collars and adjust inward until the sweet spot is found. Saves a lot of bending and trial and error.
rsv1cox- Top Poster
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Posts : 10851
Join date : 2014-08-18
Location : West Virginia
Re: Big Brother - Round one
As I went down the page I thought That we were going to see her in action The idea with the collars is good Can't wait to see it in action
davidll1984- Diamond Member
- Posts : 2303
Join date : 2020-02-12
Age : 39
Location : shawinigan
Re: Big Brother - Round one
Same, and now we know how much it weighs, I reckon its really going to go! with three engines all running! Keen to see or hear how it goes. :-)
Yabby
Yabby
Yabby- Platinum Member
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Posts : 711
Join date : 2021-06-08
Location : Yorke Peninsula South Australia
Re: Big Brother - Round one
Fingers crossed in anticipation here!
NEW222- Top Poster
- Posts : 3895
Join date : 2011-08-13
Age : 45
Location : oakbank, mb
Re: Big Brother - Round one
Everybody is way to optimistic - this thing ain't gonna lift off the ground, much less fly. We are talking over two pounds of dead weight here.
It might IF I remove the pontoons and replace with a tricycle landing gear assembly. Lot's of drag on those four wheels and the two front wheels fight each other in the turns, and it's all just one great big turn. I am thinking about removing the two front wheels and replacing with a single wheel located in the middle of the front axle.
My goal is to get it to go around in a circle, if it does lift off I will be happy to eat my hat.
Bob
It might IF I remove the pontoons and replace with a tricycle landing gear assembly. Lot's of drag on those four wheels and the two front wheels fight each other in the turns, and it's all just one great big turn. I am thinking about removing the two front wheels and replacing with a single wheel located in the middle of the front axle.
My goal is to get it to go around in a circle, if it does lift off I will be happy to eat my hat.
Bob
rsv1cox- Top Poster
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Posts : 10851
Join date : 2014-08-18
Location : West Virginia
Re: Big Brother - Round one
I am not entirely sure what Mark is talking about but my thought is to mount the bridle so it yaws outward. Maybe that is what Mark was saying.
Another thought would be to dial some drag into the outboard wheels.
Another thought would be to dial some drag into the outboard wheels.
Cribbs74- Moderator
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Posts : 11904
Join date : 2011-10-24
Age : 50
Location : Tuttle, OK
Re: Big Brother - Round one
You might try canting the the wheels to naturally follow the arc of the circle instead of rolling straight….. Probably most efficient if done both front and back…. Bridle adjust should help too…Watching…. And good luck!!
rdw777- Diamond Member
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Posts : 1470
Join date : 2021-03-11
Location : West Texas
Re: Big Brother - Round one
It's all about the center of gravity, or in this case - the center of pull. Rolling resistance too. I replaced the two front wheels with a single larger wheel and it reduced the rolling resistance dramatically. One finger push now and it just rolls.
Tried a Cox Mercedes tether car with just a single point of attachment for the bridle.
Begs the question - why not just epoxy an eyelet into the cg point of the lower wing......................
Tried a Cox Mercedes tether car with just a single point of attachment for the bridle.
Begs the question - why not just epoxy an eyelet into the cg point of the lower wing......................
rsv1cox- Top Poster
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Posts : 10851
Join date : 2014-08-18
Location : West Virginia
Re: Big Brother - Round one
Cribbs74 wrote:I am not entirely sure what Mark is talking about but my thought is to mount the bridle so it yaws outward. Maybe that is what Mark was saying.
Another thought would be to dial some drag into the outboard wheels.
That was the problem, it yawed outward too much as the center of pull was wrong. It just headed out from the circle crabbing instead of staying parallel to it. Moving the center of pull forward toward the nose will cure that.
I had thought about inducing drag into the outboard wheels (if it tended to come in on the tether line) by adding silicone tubing between the pontoons and the wheels and adjusting compression.
rsv1cox- Top Poster
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Posts : 10851
Join date : 2014-08-18
Location : West Virginia
Re: Big Brother - Round one
Yea Bob , as usual there are adjustments to bee made , I think the single wheel in the front looks better anyway . That CG with the eyelet may be the trick (sounds good anyway ) Does Mark have a YouTube acct? If so why not get him to video the action and post ,, If he is there of coarse .
getback- Top Poster
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Posts : 10276
Join date : 2013-01-18
Age : 66
Location : julian , NC
Re: Big Brother - Round one
Found out why the Golden Bee wouldn't run. No venturi gasket. I think I built this engine from parts with a later plastic backplate that has vents, not a problem on this as it won't be doing any loops.
Replaced the gasket and working on struts. Lot's of different styles, V's, N's, but I came up with my own - call them H's Experimental trial fit. Paint to follow but won't put them in until I have ran it a couple of times. Thinking about removing the bridle and just tethering it with the wing eyelet unless someone has a better idea.
Neither one of us have a youtube account Eric, maybe there is another way to post a video.
Replaced the gasket and working on struts. Lot's of different styles, V's, N's, but I came up with my own - call them H's Experimental trial fit. Paint to follow but won't put them in until I have ran it a couple of times. Thinking about removing the bridle and just tethering it with the wing eyelet unless someone has a better idea.
Neither one of us have a youtube account Eric, maybe there is another way to post a video.
rsv1cox- Top Poster
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Posts : 10851
Join date : 2014-08-18
Location : West Virginia
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