A new DickeyBird project.
09-28-2007, 09:21 PM
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A new DickeyBird project.
Still no balsa chips from DickeyBird Aviation but at least I did some meaningful work in the model airplane side of things.
The task was to make a few special venturis for my friend Allen Worley, proprietor of Planet Hobby, local distributor of NovaRossi engines. Seemed like a simple task at first; just a little lathe and mill work from 6061 aluminum to fit a .15 engine.
Problem #1 came when I had to precisely position a radiused cut in the side. The venturi is held in the intake opening by the spraybar and an O-ring. If it fits properly, you can press down hard on the venturi to compress the O-ring, then slide in the spraybar.
Turning & drilling the part to the correct overall dimensions was pretty easy but I struggled trying to figure how to precisely measure and position that pesky little cut in the side. It finally became clear that I would have to measure its location in 2 axes accurately and draw it out in CAD. The pic shows a parallel held flat against the top surface and a #46 drill slid snugly between the spray-bar and the parallel. This gave me one of the dimensions and the other was obtained with an inside mike fitted between the spray-bar and the opposite wall of the inlet opening. Using these dimensions I was able to draw it up in CAD and establish the exact offsets required to position the cut, allowing for the compression of the O-ring using the S.W.A.G. method.
I cut a V-jig (thanks Roger for bestowing that trick upon me) to go in place of the fixed jaw in the mill vise so all the venturi blanks could be indexed consistently (had to make 7 of ‘em)
I used an edge finder, the CAD sketches and my best Jetthro Bodine cypherin’ to move the table to the theoretical position indicated and locked it down. I spun the mill up to speed and made the quick little plunge with a 5/32†endmill. I held my breath while I slipped the O-ring on, pressed down HARD and pushed in the spray-bar. HALLELUJAH, THE DANG THING FIT PERFECTLY!
Problem #2: The elation didn’t last long though because I still hadn’t figured out how to make a nicely radiused curve to transition from the tiny little 4mm I.D. to the large O.D., exactly the same on 7 venturis. This special venturi is for some type of u/c spec. racing that allows a max I.D. of 4 mm. I found an old HSS 1/2" radius roundover router bit and with a little finagling in CAD, found that the radius would work. The small end was way too big though to blend into the I.D., even with the bearing removed so I chucked it up in a Spin-Indexer to hold it steady and worked on it with a thin cutoff disc in a Dremel by hand to reshape it. I used a height gauge/pointer to ensure the flutes were reasonably symmetrical as it was rotated by hand and also to make sure it had some relief ground in. Since it had been abused and was blackened with burned pine rosin, I (very uncharacteristically) took the time to work the cutting edges over with a fine grit aluminum oxide "toolroom finishing stick" 'til it was pretty sharp. I've never had any luck with form tools before but this one was a pleasant surprise.
Again using CAD, I measured the depth needed, chucked the tool up in the tailstock chuck and tried a test cut in some scrap to establish the best speed for a chatter free cut; which turned out to be the slowest speed my lathe will run. Again I held my breath and plunged my cobbled up form tool into the real part. UNBELIEVABLE; it peeled off some beautiful, wide chips and worked great!
Since it was a factory ground router bit, I was able to modify the small end to crudely match the profile that was put there by someone that knew his stuff. It still ain't real pretty to look at but the cut has that feel that tells you it's doing what it's supposed to do. Nothing like my previous form tool efforts which always end up sounding like an enraged boar screeching at the top of his lungs...or maybe l-o-n-g fingernails dragging across a blackboard really hard.
Anyhoo, it was an interesting project and I didn’t make any defective parts for a change!
The task was to make a few special venturis for my friend Allen Worley, proprietor of Planet Hobby, local distributor of NovaRossi engines. Seemed like a simple task at first; just a little lathe and mill work from 6061 aluminum to fit a .15 engine.
Problem #1 came when I had to precisely position a radiused cut in the side. The venturi is held in the intake opening by the spraybar and an O-ring. If it fits properly, you can press down hard on the venturi to compress the O-ring, then slide in the spraybar.
Turning & drilling the part to the correct overall dimensions was pretty easy but I struggled trying to figure how to precisely measure and position that pesky little cut in the side. It finally became clear that I would have to measure its location in 2 axes accurately and draw it out in CAD. The pic shows a parallel held flat against the top surface and a #46 drill slid snugly between the spray-bar and the parallel. This gave me one of the dimensions and the other was obtained with an inside mike fitted between the spray-bar and the opposite wall of the inlet opening. Using these dimensions I was able to draw it up in CAD and establish the exact offsets required to position the cut, allowing for the compression of the O-ring using the S.W.A.G. method.
I cut a V-jig (thanks Roger for bestowing that trick upon me) to go in place of the fixed jaw in the mill vise so all the venturi blanks could be indexed consistently (had to make 7 of ‘em)
I used an edge finder, the CAD sketches and my best Jetthro Bodine cypherin’ to move the table to the theoretical position indicated and locked it down. I spun the mill up to speed and made the quick little plunge with a 5/32†endmill. I held my breath while I slipped the O-ring on, pressed down HARD and pushed in the spray-bar. HALLELUJAH, THE DANG THING FIT PERFECTLY!
Problem #2: The elation didn’t last long though because I still hadn’t figured out how to make a nicely radiused curve to transition from the tiny little 4mm I.D. to the large O.D., exactly the same on 7 venturis. This special venturi is for some type of u/c spec. racing that allows a max I.D. of 4 mm. I found an old HSS 1/2" radius roundover router bit and with a little finagling in CAD, found that the radius would work. The small end was way too big though to blend into the I.D., even with the bearing removed so I chucked it up in a Spin-Indexer to hold it steady and worked on it with a thin cutoff disc in a Dremel by hand to reshape it. I used a height gauge/pointer to ensure the flutes were reasonably symmetrical as it was rotated by hand and also to make sure it had some relief ground in. Since it had been abused and was blackened with burned pine rosin, I (very uncharacteristically) took the time to work the cutting edges over with a fine grit aluminum oxide "toolroom finishing stick" 'til it was pretty sharp. I've never had any luck with form tools before but this one was a pleasant surprise.
Again using CAD, I measured the depth needed, chucked the tool up in the tailstock chuck and tried a test cut in some scrap to establish the best speed for a chatter free cut; which turned out to be the slowest speed my lathe will run. Again I held my breath and plunged my cobbled up form tool into the real part. UNBELIEVABLE; it peeled off some beautiful, wide chips and worked great!
Since it was a factory ground router bit, I was able to modify the small end to crudely match the profile that was put there by someone that knew his stuff. It still ain't real pretty to look at but the cut has that feel that tells you it's doing what it's supposed to do. Nothing like my previous form tool efforts which always end up sounding like an enraged boar screeching at the top of his lungs...or maybe l-o-n-g fingernails dragging across a blackboard really hard.
Anyhoo, it was an interesting project and I didn’t make any defective parts for a change!
09-29-2007, 03:11 PM
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RE: A new DickeyBird project.
ORIGINAL: DICKEYBIRD
.....Anyhoo, it was an interesting project and I didn’t make any defective parts for a change!
.....Anyhoo, it was an interesting project and I didn’t make any defective parts for a change!
Nicely done and well written up. Making up jigs and other special tooling is a field all of its own and is not always that simple. You've done well Grasshopper...
09-29-2007, 07:35 PM
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RE: A new DickeyBird project.
ORIGINAL: BMatthews
You realize that when Murphy doesn't show for one project he saves it up for double on the next.......
Nicely done and well written up. Making up jigs and other special tooling is a field all of its own and is not always that simple. You've done well Grasshopper...
ORIGINAL: DICKEYBIRD
.....Anyhoo, it was an interesting project and I didn’t make any defective parts for a change!
.....Anyhoo, it was an interesting project and I didn’t make any defective parts for a change!
Nicely done and well written up. Making up jigs and other special tooling is a field all of its own and is not always that simple. You've done well Grasshopper...
09-30-2007, 05:24 AM
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RE: A new DickeyBird project.
Hi Milton, beautiful fitting and turning work there. I wish you'd move to Australia, my main focus these days is control line flying. I'm always converting E**y bought OS R/C engines to C/L specs. The local supply of NVA's and venturis seems to be exhausted and I've heard OS no longer do C/L engines.
What have you been building lately? The Forum needs some more of your input, like the good old days.......John
What have you been building lately? The Forum needs some more of your input, like the good old days.......John
09-30-2007, 08:26 AM
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RE: A new DickeyBird project.
Hi John, thanks for the kind words.
Yup, I long for the good ol' days too. Losing my best ol' flying buddy back in April has really knocked the wind out of me. We had a very special 27 year friendship that will be hard to replace. I didn't realize it at the time but the designing and building process for me was hugely affected by our relationship. We were always heckling each other unmercifully over our latest projects, trying to (good-naturedly) out-do the other with Cox power being the common interest.
What little spare time I seem to find these days is spent making metal projects, mostly tooling for the lathe and mill. Don't ask me where I'm going with that endeavor because I don't have a clue! I've always had a cyclical pattern in my hobbies and go with whatever dominates my daydreams at the time. I'm currently fascinated with and planning to build a Flame Licker or a Stirling engine. I just have to build up my cache of tooling!
I'm sure one of these days I'll wake up with a new aircraft project burning to be completed. With the success I had with the P-Jay elliptical wing, I've been thinking about a large, lightweight u/c model with transparent covered built-up elliptical wing & tail surfaces and a stick built fuse for the 50¢ Fox .25 Kathy brought home from a yard sale years ago. It's an r/c version so I'd be forced to build a venturi to replace that funky, slanted carb with the bolt-on flange. I also have a couple Webra Speed .28's I could play with too.
Yup, I long for the good ol' days too. Losing my best ol' flying buddy back in April has really knocked the wind out of me. We had a very special 27 year friendship that will be hard to replace. I didn't realize it at the time but the designing and building process for me was hugely affected by our relationship. We were always heckling each other unmercifully over our latest projects, trying to (good-naturedly) out-do the other with Cox power being the common interest.What little spare time I seem to find these days is spent making metal projects, mostly tooling for the lathe and mill. Don't ask me where I'm going with that endeavor because I don't have a clue!
I've always had a cyclical pattern in my hobbies and go with whatever dominates my daydreams at the time. I'm currently fascinated with and planning to build a Flame Licker or a Stirling engine. I just have to build up my cache of tooling!I'm sure one of these days I'll wake up with a new aircraft project burning to be completed. With the success I had with the P-Jay elliptical wing, I've been thinking about a large, lightweight u/c model with transparent covered built-up elliptical wing & tail surfaces and a stick built fuse for the 50¢ Fox .25 Kathy brought home from a yard sale years ago. It's an r/c version so I'd be forced to build a venturi to replace that funky, slanted carb with the bolt-on flange. I also have a couple Webra Speed .28's I could play with too.
09-30-2007, 10:49 AM
#6
RE: A new DickeyBird project.
Nice work on your venturi's Dickeybird.
Be careful, getting addicted to machining, It can be very exspensive, its a tough road to go down. Machining is my trade, I have done it for 8-10 hrs a day for the last 34 yrs now and I still come home and do more in the garage. I havent figured out if it is the model engines I play with or what the real attraction is....I need therepy [
]
Be careful, getting addicted to machining, It can be very exspensive, its a tough road to go down. Machining is my trade, I have done it for 8-10 hrs a day for the last 34 yrs now and I still come home and do more in the garage. I havent figured out if it is the model engines I play with or what the real attraction is....I need therepy [
]
09-30-2007, 01:26 PM
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RE: A new DickeyBird project.
ORIGINAL: DICKEYBIRD
Losing my best ol' flying buddy back in April has really knocked the wind out of me. We had a very special 27 year friendship that will be hard to replace. I didn't realize it at the time but the designing and building process for me was hugely affected by our relationship. We were always heckling each other unmercifully over our latest projects, trying to (good-naturedly) out-do the other with Cox power being the common interest.
Losing my best ol' flying buddy back in April has really knocked the wind out of me. We had a very special 27 year friendship that will be hard to replace. I didn't realize it at the time but the designing and building process for me was hugely affected by our relationship. We were always heckling each other unmercifully over our latest projects, trying to (good-naturedly) out-do the other with Cox power being the common interest.
You have my utmost sympathy. I have a hunting companion of 32 years that probably mirrors your friendship. Obviously, both of us are getting long in the tooth. If something happened to him, I think I will likely stop waterfowling. All those hours in the boats and blinds have grown from the enjoyment of the hunt to the enjoyment of the friendship.
I wish you well.
andrew
09-30-2007, 01:57 PM
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RE: A new DickeyBird project.
Thanks Andrew...Brian & I were fishin' buddies as well! We slacked off the airplane thing for a few years back in the early 90's and started fishing every weekend...eventually we found we were so busy talking about all the new designs we wanted to do while we in the boat we finally gave up and went back to our real passion.
Toad, I feel your pain. I'm in the auto service business and for many years I'd work on 'em all day and then come home and restore/modify 'em in the garage at night but that stopped about the same time I got back into model airplanes. Now I have to FORCE myself to even change the oil in our cars!
I've been driving my van around all summer with the a/c only blowing out the defrost vents. Finally got around just yesterday to tracing it down to a vacuum leak in one of the controls. What'd I do? Stuck a piece of 1/8" birch wing dowel in the hose to stop the leak and called it GOOD! (Who needs rear air anyway?)
Toad, I feel your pain. I'm in the auto service business and for many years I'd work on 'em all day and then come home and restore/modify 'em in the garage at night but that stopped about the same time I got back into model airplanes. Now I have to FORCE myself to even change the oil in our cars!
I've been driving my van around all summer with the a/c only blowing out the defrost vents. Finally got around just yesterday to tracing it down to a vacuum leak in one of the controls. What'd I do? Stuck a piece of 1/8" birch wing dowel in the hose to stop the leak and called it GOOD! (Who needs rear air anyway?)
09-30-2007, 02:21 PM
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RE: A new DickeyBird project.
LOL DB , a typical mechanics fix of his own car, but being one too I can relate, after 8hrs fixing everyone elses who wants to go home and work on more dam cars. Restorations ecepted.
Stewart
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09-30-2007, 06:12 PM
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RE: A new DickeyBird project.
Very nice!
I admit that I did see your work on another website before this but I am at a loss at to which one and haven't been able to find it again
This hobby (just about any hobby I can think of) is not just about building and flying, it is more about the comraderie and friendships, long and short term that develop. It is truly a social thing and extended well beyond the flying field.
I have gotten lost in home machining too. Like you, it seems whatever strikes my fancy is where I wonder off to. That is a good thing perhaps in that it keeps me from getting burnt out on only just one thing.
I sit in front of computer all day at work and the last thing I want to do is sit in fron of one when I get home - that's why I don't spend much time reading through the various on line forums.
cheers, Graham in Embrun near Ottawa Canada
I admit that I did see your work on another website before this but I am at a loss at to which one and haven't been able to find it again
This hobby (just about any hobby I can think of) is not just about building and flying, it is more about the comraderie and friendships, long and short term that develop. It is truly a social thing and extended well beyond the flying field.
I have gotten lost in home machining too. Like you, it seems whatever strikes my fancy is where I wonder off to. That is a good thing perhaps in that it keeps me from getting burnt out on only just one thing.
I sit in front of computer all day at work and the last thing I want to do is sit in fron of one when I get home - that's why I don't spend much time reading through the various on line forums.
cheers, Graham in Embrun near Ottawa Canada
09-30-2007, 06:21 PM
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RE: A new DickeyBird project.
Thanks Graham, good to hear from you. I tend to hang out at the 1st forum below when I feel like metal talk and I've just joined at the other one for it's home-made model engine info. I want to build a "flame-licker" BAD!
http://bbs.homeshopmachinist.net/forumdisplay.php?f=3
http://homemodelengine.freeforums4u.com/
10-03-2007, 02:58 PM
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RE: A new DickeyBird project.
DB, I like the V-block! Man, if that ain't a time saver, I don't know what is. BTW, you ought to ride to the Southeastern Model Show in Perry, GA with Allen next March. He's a real nice guy. We need to bug him about importing the smaller Novarossi's. They've got a nice .09 and a hellacious .12
10-03-2007, 04:22 PM
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RE: A new DickeyBird project.
Good Lord DB! You've became a full-fledged chip chimp! So far I've resisted the allure but I use one of my lathes for something almost every day I get to spend in the shop, I have no idea how I managed to muddle along without one for so many years at this juncture!
<Losing my best ol' flying buddy back in April has really knocked the wind out of me.>
Very sorry to hear that! But I do understand. When we lost Randy Randolph my interest in modeling seemed to go with him. I just can't seem to work up the enthusiasm to design and build something any more without Randy around to bounce ideas off of.
<I've always had a cyclical pattern in my hobbies and go with whatever dominates my daydreams at the time.>
Very much the same syndrome here. And not being a multi-tasker I can only handle one hobby at a time. For the last few years that has been reviving vintage outboards. That will make one appreciate their machine tools!
<Brian & I were fishin' buddies as well>
That WILL knock the wind out of your sails! Just last Winter I started flyfishing again seriously. So between old outboard projects I've been building rods, tying flies and rehabbing vintage tackle. Keeps me at home and out of bars away from low companions.
<I---just joined---one for it's home-made model engine info.>
Oh crap! Did you just hafta put that up? OK----I'm hooked---I'm heading over there. Just what I needed---another passion.
Tom @ Buzzard Bluff
<Losing my best ol' flying buddy back in April has really knocked the wind out of me.>
Very sorry to hear that! But I do understand. When we lost Randy Randolph my interest in modeling seemed to go with him. I just can't seem to work up the enthusiasm to design and build something any more without Randy around to bounce ideas off of.
<I've always had a cyclical pattern in my hobbies and go with whatever dominates my daydreams at the time.>
Very much the same syndrome here. And not being a multi-tasker I can only handle one hobby at a time. For the last few years that has been reviving vintage outboards. That will make one appreciate their machine tools!
<Brian & I were fishin' buddies as well>
That WILL knock the wind out of your sails! Just last Winter I started flyfishing again seriously. So between old outboard projects I've been building rods, tying flies and rehabbing vintage tackle. Keeps me at home and out of bars away from low companions.
<I---just joined---one for it's home-made model engine info.>
Oh crap! Did you just hafta put that up? OK----I'm hooked---I'm heading over there. Just what I needed---another passion.
Tom @ Buzzard Bluff
10-04-2007, 06:48 AM
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RE: A new DickeyBird project.
Hey Tom...long time, no see! Good to hear you're still busy & having fun.
Vintage outboards, cool! Brian & I had a '57 Merc Mark 28 (18 hp.) on our '57 Arkansas Traveler 14 ft. V-bottom alum. boat. It was in good shape other than needing fresh rings & a hone job, a new upper main bearing and a water pump inpeller. It even had (and I say HAD) a beautiful, un-dinged 2 blade BRASS prop. After 3 seasons of fishing, it picked up a few dings that I had to straighten. I repainted it black with 2-part auto paint which looked great but probably wasn't a good idea, historically. I loved the little cast logo plate that said "Powered by the Famous Hurricane Engine."
The boat had been painted with an awful blue color before we got her so I stripped it off to expose the original aluminum. I had to rebuild the transom and replace some rivets here & there but it was a beautiful little thing and very rugged.
We decommissioned her a couple years ago to make room for machine tools in my shop and she now sits out of the weather in a friend's barn. One of these days....
Hey Patrick, I've been saying I need to go to Perry one of these days. We'll have to wait & see what the budget will alllow.
Vintage outboards, cool! Brian & I had a '57 Merc Mark 28 (18 hp.) on our '57 Arkansas Traveler 14 ft. V-bottom alum. boat. It was in good shape other than needing fresh rings & a hone job, a new upper main bearing and a water pump inpeller. It even had (and I say HAD) a beautiful, un-dinged 2 blade BRASS prop. After 3 seasons of fishing, it picked up a few dings that I had to straighten.
I repainted it black with 2-part auto paint which looked great but probably wasn't a good idea, historically. I loved the little cast logo plate that said "Powered by the Famous Hurricane Engine."The boat had been painted with an awful blue color before we got her so I stripped it off to expose the original aluminum. I had to rebuild the transom and replace some rivets here & there but it was a beautiful little thing and very rugged.
We decommissioned her a couple years ago to make room for machine tools in my shop and she now sits out of the weather in a friend's barn. One of these days....
Hey Patrick, I've been saying I need to go to Perry one of these days. We'll have to wait & see what the budget will alllow.
