Mike's Build Log
Moderator: Mike Everman
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Mike's Build Log
Hi guys. I decided to take another shot at the little 2" diameter (what I used to call "pockey lockey")
This one will get a tuned expansive tail after I get some time with the straight pipe version.
It has a removable head and telescoping intake (that's a .010" sleeve in there with a nice snug, but sliding fit.
I've got a raging cold, so didn't go out to the shop to run it today, but put a rossco in it int the garage, just enough to know it's going to go, and it's gonna.
This one will get a tuned expansive tail after I get some time with the straight pipe version.
It has a removable head and telescoping intake (that's a .010" sleeve in there with a nice snug, but sliding fit.
I've got a raging cold, so didn't go out to the shop to run it today, but put a rossco in it int the garage, just enough to know it's going to go, and it's gonna.
- Attachments
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- pockey locky2, intake slider small.JPG (60.87 KiB) Viewed 31078 times
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- pockey locky2, straight pipe small.JPG (75.6 KiB) Viewed 31083 times
Mike Often wrong, never unsure.
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Oh yeah, I forgot to post some progress! And no, the bolt on is so I can change fuel hole number and diameter. (Fueling is set up like most of my motors; outer distribution volume and holes in the intake flare at the CC)
I ran it the other day. Went really well, and ran right out of the box. I could tell I didn't have enough fuel jet area, as I was not able to over-fuel it.
The oddest thing happened, as I ran the throttle down to go low. It spit the intake out. It still ran, though, with a 2" long intake with no flare! The intake and exhaust are both 1" od, .035" wall. That's going from about 4.5:1 to 2:1 on the intake aspect ratio.
The frequency jumped way up after spitting out the intake, but it wasn't "howling mode". I wish I'd been doing thrust measurements and taking video at the time.
Hopefully Sunday night I'll get some video and thrust, then move on to adding the tuned pipe tail I'm planning. I want to shorten the sliding portion of the intake so I can adjust below 4.5:1 ratio as I cannot now.
I ran it the other day. Went really well, and ran right out of the box. I could tell I didn't have enough fuel jet area, as I was not able to over-fuel it.
The oddest thing happened, as I ran the throttle down to go low. It spit the intake out. It still ran, though, with a 2" long intake with no flare! The intake and exhaust are both 1" od, .035" wall. That's going from about 4.5:1 to 2:1 on the intake aspect ratio.
The frequency jumped way up after spitting out the intake, but it wasn't "howling mode". I wish I'd been doing thrust measurements and taking video at the time.
Hopefully Sunday night I'll get some video and thrust, then move on to adding the tuned pipe tail I'm planning. I want to shorten the sliding portion of the intake so I can adjust below 4.5:1 ratio as I cannot now.
Mike Often wrong, never unsure.
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Pockey Locky puts out 3.5 lb!
Well, that was sure the best test ever. I'm starting to reap some benefit from my acoustic model, and that is very satisfying.
I drilled a couple more .028" holes in the fuel plenum, and this motor pulled 3.3 lb stable, running rough at 3.5. Or, surging to 3.5 from 3.3, I can't remember. Over 2 was going to be good, 3.5 is dancing time. OK, I'm easily amused. ;-)
I'll attach a walk around vid, and post some vids at 1 lb and 3 lb thrust for sound analysis folk.
Also, I'm attaching all the dims. Kind of self explanitory, but not a very convenient format.
I'm so stoked about the thrust!
Pockey Lockey 2 (I've got to think of a better name.)
29.74" long
2"OD x .035 wall CC, long rear cone
1" x.035 intake and tail tubes
I drilled a couple more .028" holes in the fuel plenum, and this motor pulled 3.3 lb stable, running rough at 3.5. Or, surging to 3.5 from 3.3, I can't remember. Over 2 was going to be good, 3.5 is dancing time. OK, I'm easily amused. ;-)
I'll attach a walk around vid, and post some vids at 1 lb and 3 lb thrust for sound analysis folk.
Also, I'm attaching all the dims. Kind of self explanitory, but not a very convenient format.
I'm so stoked about the thrust!
Pockey Lockey 2 (I've got to think of a better name.)
29.74" long
2"OD x .035 wall CC, long rear cone
1" x.035 intake and tail tubes
- Attachments
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- geometry.JPG (93.72 KiB) Viewed 30370 times
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- pockey lockey 2 starting.wmv
- (964.01 KiB) Downloaded 11595 times
Mike Often wrong, never unsure.
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Pockey Locky puts out 3.5 lb!
1 and 3 lb videos.
- Attachments
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- 3 lb thrust setting.wmv
- (1.07 MiB) Downloaded 11576 times
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- 1 lb thrust setting.wmv
- (373.89 KiB) Downloaded 11567 times
Mike Often wrong, never unsure.
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Pocket Rocket
Dear Mike.
Thanks for pointing me to this. This motor asks a lot of questions! Nice build and plenty of power.
Can't wait to see the next stage build on upon these results.
As always my Best Regards to you and the family.
Graham.
Thanks for pointing me to this. This motor asks a lot of questions! Nice build and plenty of power.
Can't wait to see the next stage build on upon these results.
As always my Best Regards to you and the family.
Graham.
Dark days nurture new
light. Productions begin.
Now open your eyes.
light. Productions begin.
Now open your eyes.
Pockey Locky puts out 3.5 lb!
I really liked the two colors Mike, that effect would be fun to strive for on other pulsating combustion toys - add two or more spectra to the show. My computer makes the flames look orange and green. Maybe you could turn the lights down low and put on some soft music. Or just turn the lights down low to see the pretty colors better. ha
Good observation there Eric about the blue flame being drawn down.
Good observation there Eric about the blue flame being drawn down.
Presentation is Everything
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Pockey Locky scale up
So I've been noodling out a scaling process, and now I feel that before I move on to the tuned tail for the 2 incher, I want to do a quick build to see if the scaling works.
The driving factor is the u-bend I can use, that is 1.5" OD x .065 wall. The 2" motor had a 1" u-bend.
So the results of my scaling are thus:
CC dia: 2.631" from 1.93"
Length factor: 1.539x
Diameter factor (on all but CC): 1.473x
Max Thrust (with 3.3 lb used from the 2 incher): 7.16 lb.
It certainly wouldn't be the first time a theory falls, if it does, but oh what a thrill if I get the 7 lb and prove the scaling.
I only theorized the scaling last night, so I haven't got a lot of ego wrapped up in it. It fell together far too neatly to be true, ha.
The driving factor is the u-bend I can use, that is 1.5" OD x .065 wall. The 2" motor had a 1" u-bend.
So the results of my scaling are thus:
CC dia: 2.631" from 1.93"
Length factor: 1.539x
Diameter factor (on all but CC): 1.473x
Max Thrust (with 3.3 lb used from the 2 incher): 7.16 lb.
It certainly wouldn't be the first time a theory falls, if it does, but oh what a thrill if I get the 7 lb and prove the scaling.
I only theorized the scaling last night, so I haven't got a lot of ego wrapped up in it. It fell together far too neatly to be true, ha.
- Attachments
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- pocky locky scale up.PNG (174.34 KiB) Viewed 30006 times
Mike Often wrong, never unsure.
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