Ageless 9 and 18 Radial

[--colin--]

Upgraded the ignition wire to 20kv wire. Big improvement. Still tweaking the mixture. Hope to get more runs this week during the holidays. 8/9. It runs better and better with each run. I made an inlet Venturi to increase the velocity of the air stream across the carb pitot. Not sure if it is helpful or not. I am going to completely rewire the 18 with the better wire and spacers. Merry Christmas!
View attachment 143187
View attachment 143186

Very nice to see it running. Congratulations.

 

[rweber]

Congratulations! Nice Work! How did you this thermal video?

 

[Bentwings]

I like that thermo view , too how did you make it ?

 

[Bentwings]

Today I was digging around an idea for another project of mine the subject of planetary gears and gear boxes enters the picture . I thought about your scroll intake these are more fuel air mixers rather than superchargers . A number have been built as superchargers but these don’t function well as you can’t really drive them fast enough and t ver high speeds the scroll cavatates destroying any chance of moving air Way back when I first got the Hogson drawing set I looked into dual staging the scroll , one discharging into the second . I stopped sbout there as med condition precluded fancy machine shop work adding a second stage or even a third stage would not be too hard as these planetary drives are based on nema stepper motor sizes the drives should be easily reversible with at most a shaft connector some are as high as 30:1 So even if the “ supercharger “ were driven electrically you could get some big rpm it’s hard to get the air flow in these small scrolls but you could substantially increase the volume available fuel air mix and it would be really stirred up ! So getting it to flow down the intake pipes should be easier

As I recall there is an easy shaft mount on the crank to off you chose to crank drive I YHINK I’d go with electric as you could creat some flow control by just barring the scroll speeds Just a thought for you to ponder I’m goingvto order one of these in nema 17 as I have several stepper motors this size mostly just for fun . The guy that originally designed these turbines did quite a bit of work on small scroll or centrifugal blowers he never got enough flow to blow up a plastic bag and ultimately the high speed scroll blew up I haven’t seen anything since then I YHINK the best way would be to build a model of gmc diesel blower which is positive displacement so it would feed the scroll positive air. Conley engines makes these and they produce boost on his v 8 engines 5 psi I YHINK that’s pretty good for small supercharger . Several of these have been built I YHINK cad models are on grab cad but I really don’t know how to use that . The back of my mind says to 3 d print a test model just for fun there is a print service not too far from me . I have no idea what he charges But it would be possible to get the case , end plates gears and rotors done all at one time so it might be practical. . I’ll keep thinking on this feel free to question me . We actually have a complete near new gmc 6-71 blower so it would be relatively easy to get measurements if I could get out to the shop or have my son bring it over to me .

 

[peterl95124]

Today I was digging around an idea for another project of mine the subject of planetary gears and gear boxes enters the picture . I thought about your scroll intake these are more fuel air mixers rather than superchargers . A number have been built as superchargers but these don’t function well as you can’t really drive them fast enough and t ver high speeds the scroll cavatates destroying any chance of moving air Way back when I first got the Hogson drawing set I looked into dual staging the scroll , one discharging into the second . I stopped sbout there as med condition precluded fancy machine shop work adding a second stage or even a third stage would not be too hard as these planetary drives are based on nema stepper motor sizes the drives should be easily reversible with at most a shaft connector some are as high as 30:1 So even if the “ supercharger “ were driven electrically you could get some big rpm it’s hard to get the air flow in these small scrolls but you could substantially increase the volume available fuel air mix and it would be really stirred up ! So getting it to flow down the intake pipes should be easier

As I recall there is an easy shaft mount on the crank to off you chose to crank drive I YHINK I’d go with electric as you could creat some flow control by just barring the scroll speeds Just a thought for you to ponder I’m goingvto order one of these in nema 17 as I have several stepper motors this size mostly just for fun . The guy that originally designed these turbines did quite a bit of work on small scroll or centrifugal blowers he never got enough flow to blow up a plastic bag and ultimately the high speed scroll blew up I haven’t seen anything since then I YHINK the best way would be to build a model of gmc diesel blower which is positive displacement so it would feed the scroll positive air. Conley engines makes these and they produce boost on his v 8 engines 5 psi I YHINK that’s pretty good for small supercharger . Several of these have been built I YHINK cad models are on grab cad but I really don’t know how to use that . The back of my mind says to 3 d print a test model just for fun there is a print service not too far from me . I have no idea what he charges But it would be possible to get the case , end plates gears and rotors done all at one time so it might be practical. . I’ll keep thinking on this feel free to question me . We actually have a complete near new gmc 6-71 blower so it would be relatively easy to get measurements if I could get out to the shop or have my son bring it over to me .

if you want to see a working design of a supercharger for a radial engine get the plans for the Bob Roach / Bruce Satra Pratt & Whitney 985 Wasp Junior, and the plans for the Karl-Erik Olsryd Wright J5, these both have working scale superchargers with slightly different gear arrangements that you could chose from.

I seriously suggest abandon electric, especially stepper motors which don't run smoothly (they aren't designed to run smoothly, instead they "step" from one angle to the next), your best bet would be a modern high powered RC ducted fan electric motor running on lithium batteries, but even that will have trouble delivering the power and speed a supercharger needs.

if all you want is good mixing and even flow to all 9 cylinders rather than an actual boost, then cut the gear ratio down. I have a functional model supercharger on my Rolls Royce Merlin model engine, but currently I've left the gears out because I currently only have gear ratio that is "scale" but I'm afraid that may put too much stress on the engine (powering the supercharger requires the engine to produce more power, which it gets by increasing both air flow and fuel flow, generating higher combustion pressures), when I get the time I'll retrofit with maybe 1/2 the current gear ratio which will require 1/4 the power.

if you really want to go all the way down this rabbit hole get the plans book for the Kurt Schreckling model turbojet, and the plans book for the Thomas Kamps model turbojet, which contain some of the theory of compressors, its fascinating physics, thermodynamics, engineering, and machining.

 

[Bentwings]

I agree the electric was just for static use on test stand again just a mixer

I’ll lookup your suggested reading . I’d be interested in how they operate .

A guy on the internet did a bunch of machining on a couple designs but both blew up. He even made a sort of scale Tesla supercharger but I have not seen any results of late . There was a discussion on how they work. Supposed to be very efficient but as many models don’t always scale very well I’ll look around a little more.

I would look toward a positive displacement like a semi scale roots blower. There have been a couple made that actually worked. Even these I think would bevrpm limited our race car ran an 8-71 at over 11 k rpm that’s a lot of aluminum flying around it had great boost atvthe start but dropped off down the track we used a three speed transmission so it was shifted at about u 9k rpm then we used a series of fuel control valves to limit fuel in put to try and keep mixture about right these were mechanical fuel injection with positive displacement furl pump. So by carefully reading spark plugs we could adjust mixture. We would burn about 15 gallons of alcohol per run the blower was getting tired andvthe nylatron strips sealing the rotors were showing wear . Some of the new technology had not been proven yet so we were a little out of the loop. These run a lot faster now and produce incredible boost pressures considering 500+ cu in engines the addition of nitro made up for blower inefficiency some but we really needed a new unit . It was an era that will never come again . Fun while it lasted .

I’d like to see some models of the old hemi stuff

 

[rlo1]

I like that thermo view , too how did you make it ?

Check out - https://www.amazon.com/gp/product/B0B4PXYRS1/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 works nice.

 

[peterl95124]

I like that thermo view , too how did you make it ?

have to agree, that's an awesome view, pricey but awesome,
I just put my finger in the exhaust to tell if its hot or cold,
but that imager sure seems like a fun toy to have

 

[Bentwings]

Inlet and exhaust pipes are tuned - whether planned or not - because that's what gases do...
A gas moving in a tube will have resonances based on pressure, temperature, pulsation rate, etc. - all of which affect engine performance to some degree.
How much this affects engine running is more black-art than science, but most motorcycle and car makers have mastered the art to increase power/efficiency and reduce noise.
Scaling "older" designs creates new conditions that do not linearly change with scale, so may have more or less effect than on the original engines.
K2

I hope this is the right place . I’ve had on going problems trying to get in a succession of replies correctly.

SO. To day I was going to get on grab cad and look for a file I wanted . I found that this cool site is going off line in a couple months at best. The note was its run its course . I’ve seen many down loads from it that were very nice. Others have noted it as a very useful site . So now what? Does it just evaporate I saw a couple notes that there may be some connection with solid works and Acad. but it appears it’s going away. I like to see other comments I’m way behind my SW program as I’ve just had endless doc appointments and visits then the rediculous winter near record for our area . I managed to injure my back shoveling. Something I’m not even supposed to do. It’s almost healed up . Mean time I’ve become tangled in metric threads . I have a large bin of them now and I have to guess I couldn’t pick a correct one . I did get a pretty complete chart but do to weak eye sight I need a mag glass just to read it most taps are marked but don’t seem to match up to physical measurement . I was just getting back into the steamer as I came into a larger boiler tube so I wanted to continue with it . I’ve had to put it away temporarily as the in home inspection is coming up and I suspect my lease may not allow this hobby stuff . I can get around it by being very careful and testing in more appropriate conditions . More later. I’m just at a loss over grab cad as I was counting on there being some things I could use there .


Anyway how about some comments

 

[rlo1]

I hope this is the right place . I’ve had on going problems trying to get in a succession of replies correctly.

SO. To day I was going to get on grab cad and look for a file I wanted . I found that this cool site is going off line in a couple months at best. The note was its run its course . I’ve seen many down loads from it that were very nice. Others have noted it as a very useful site . So now what? Does it just evaporate I saw a couple notes that there may be some connection with solid works and Acad. but it appears it’s going away. I like to see other comments I’m way behind my SW program as I’ve just had endless doc appointments and visits then the rediculous winter near record for our area . I managed to injure my back shoveling. Something I’m not even supposed to do. It’s almost healed up . Mean time I’ve become tangled in metric threads . I have a large bin of them now and I have to guess I couldn’t pick a correct one . I did get a pretty complete chart but do to weak eye sight I need a mag glass just to read it most taps are marked but don’t seem to match up to physical measurement . I was just getting back into the steamer as I came into a larger boiler tube so I wanted to continue with it . I’ve had to put it away temporarily as the in home inspection is coming up and I suspect my lease may not allow this hobby stuff . I can get around it by being very careful and testing in more appropriate conditions . More later. I’m just at a loss over grab cad as I was counting on there being some things I could use there .


Anyway how about some comments

HMEM is going offline?

 

[ozzie46]

I think he means Grabcad is going offline.

Ron

 

[ninefinger]

Grabcad (the library where you are finding all the stuff you like) is not closing down, GrabCad Workbench is - which is their online CAD software platform.
See here: A Fond Farewell to GrabCAD Workbench - GrabCAD Blog

 

[byawor]

Just wondering how you made the internal gear? I do not need one just curious.
Bob

 

[rlo1]

Just wondering how you made the internal gear? I do not need one just curious.
Bob

The internal gear that is integral to the crankshaft, which is made out of stainless steel was machined in several steps. First I turned the blank in my CNC lathe, then I did all the drilling and end milling of the crank blank. The last step was using my micro arc fourth axis rotary chuck to machine the gear teeth.

 

[rlo1]

It’s been a while since I posted. I finally received after 10 months of waiting my 20kV ignition wire. I wanted a small diameter in 22ga because I didn’t want to look weird on the engine. So I ended up waiting for the right kind of wire to arrive. They had to make me a roll.

I’ve started resuming work on the 18 cylinder. I installed a new carburetor, which I think will work better than the nine cyl ones I messed with. Learned a lot when running the nine cylinder. I learned how not to do things several different ways. So now I’m trying to put the learnings together once and see how it goes on the 18.

I am slowly taking off the 10 KV wire that I know will cross fire and cause ignition problems. So I’m going cylinder by cylinder checking plug gaps and then rerouting all the new ignition wires so that I don’t have any more crossfire problems. I also found that adding a ground wire to each and every cylinder also helps with any kind of circuitry problems with the ignition system. It sure comes in handy to have a nice 3-D printer to make parts and standoffs and stuff.

It will take me at least a month or two to finish this wiring. And then I hope to start looking at running the engine sometime this summer.

 

[petertha]

I finally received after 10 months of waiting my 20kV ignition wire. I wanted a small diameter in 22ga because I didn’t want to look weird on the engine. So I ended up waiting for the right kind of wire to arrive. They had to make me a roll.

I am slowly taking off the 10 KV wire that I know will cross fire and cause ignition problems. So I’m going cylinder by cylinder checking plug gaps and then rerouting all the new ignition wires so that I don’t have any more crossfire problems. I also found that adding a ground wire to each and every cylinder also helps with any kind of circuitry problems with the ignition system.

Wow, nice build. I am a spark ignition newbie, but I want to try on next engine. But its this stuff that intimidates me haha

- If I understand, you reduced wire diameter but that necessitated increased KV? I believe that to be (higher) voltage rating, what does that translate into physically? Higher copper strand count & thinner individual diameter, or?

- can you elaborate on 'cross fire'. Like the lower KV wires created problems back at the distributer level, or issues further out amongst the ignition wires themselves? Was it rough/interrupted running or more critical than that?

- can you elaborate on your individual cylinder ground mod. Where on the cylinder does it hook up to & where do they tie back into as a common ground?

- did you mess with braided cable shielding at all? I was talking to the CH ignition guy & got the impression that shielding was necessary not only to prevent RF interference which is a bad thing for RC flying, but also bench running 'messing with ignition' for lack of better words.

 

[ozzie46]

The internal gear that is integral to the crankshaft, which is made out of stainless steel was machined in several steps. First I turned the blank in my CNC lathe, then I did all the drilling and end milling of the crank blank. The last step was using my micro arc fourth axis rotary chuck to machine the gear teeth.View attachment 147184

I think they meant the internal ring gear.

 

[rlo1]

I was wondering which one they were talking about.

The internal ring gear is a purchased brass gear ($150) that is fit into a steel ring that is machined with specific lobe, heights and distances. That part of the build was very difficult. The Cam degree table is pretty intense on this engine. The instructions in the drawings show how to do it with manual equipment. I don’t know how I could’ve done it without CNC.

 

[rlo1]

Wow, nice build. I am a spark ignition newbie, but I want to try on next engine. But its this stuff that intimidates me haha

- If I understand, you reduced wire diameter but that necessitated increased KV? I believe that to be (higher) voltage rating, what does that translate into physically? Higher copper strand count & thinner individual diameter, or?

- can you elaborate on 'cross fire'. Like the lower KV wires created problems back at the distributer level, or issues further out amongst the ignition wires themselves? Was it rough/interrupted running or more critical than that?

- can you elaborate on your individual cylinder ground mod. Where on the cylinder does it hook up to & where do they tie back into as a common ground?

- did you mess with braided cable shielding at all? I was talking to the CH ignition guy & got the impression that shielding was necessary not only to prevent RF interference which is a bad thing for RC flying, but also bench running 'messing with ignition' for lack of better words.

- If I understand, you reduced wire diameter but that necessitated increased KV? I believe that to be (higher) voltage rating, what does that translate into physically? Higher copper strand count & thinner individual diameter, or

I wanted the higher KV rated wire, but I did not want the larger size insulation required to give me the rating. The ignition modules run pretty hot with voltages exceeding 15 KV. I settled on a 22 gauge one 8th inch diameter wire. I wanted the silicone type wire and unfortunately it took 10 months to get the wire.

- can you elaborate on 'cross fire'. Like the lower KV wires created problems back at the distributer level, or issues further out amongst the ignition wires themselves? Was it rough/interrupted running or more critical than that?

Crossfire is when the ignition spark jumps from one wire to another or jumps to ground prematurely. When I had the harness bundled the spark was always inconsistent.


- can you elaborate on your individual cylinder ground mod. Where on the cylinder does it hook up to & where do they tie back into as a common ground?

The CDI Instructions are clear not to rely on the crank case ground for the ignition. I loktited every cylinder head gasket to ensure good compression. With the loktite I am worried about having a good grounds and this ensures I am getting least amount of resistance in the system. Yes I tied the grounds all together to the common ground at the CDI module. It worked well on the nine cylinder and is somewhat discrete in appearance.

- did you mess with braided cable shielding at all? I was talking to the CH ignition guy & got the impression that shielding was necessary not only to prevent RF interference which is a bad thing for RC flying, but also bench running 'messing with ignition' for lack of better words.

No, I did not use braided ignition wire. I was kind of put off by the appearance of braided wire for this.

 

[ozzie46]

I was wondering which one they were talking about.

The internal ring gear is a purchased brass gear ($150) that is fit into a steel ring that is machined with specific lobe, heights and distances. That part of the build was very difficult. The Cam degree table is pretty intense on this engine. The instructions in the drawings show how to do it with manual equipment. I don’t know how I could’ve done it without CNC. View attachment 147199View attachment 147200

I did mine with manual machines. Just have to be very deliberate and think about what needs to be done continually. I have DROs on my mill/ drill, so that helped immensely.

Ron