dark white lightning

I had an old looking Aerotech F25 of completely unknown history to launch this weekend, and I was a little surprised by how it looked while burning. Performance seemed fine, and I did not notice anything off about the sound, but the smoke looked dark! Not black like one of the black jacks or smokey sams, but far darker than expected.

Has anyone else ever noticed that, either with an F25 or white lightning in general? It could be age, handling, temperature fluctuation, random variance, or any number of factors.

Maybe a mislabeled F26??

Great point. Not quite that dark, though, and judging by the age of the casing it may predate F26 production!

I have seen this.

"Darker" smoke can be caused by the paper liner burning or your view of the rocket in relation to the sun.

I'm pretty sure it's caused by the paper liner burning, which would burn with a darker smoke

Nate

Yes, here is a very old F40, no flame at all and dark smoke.

[video=youtube_share;uXXBIwW2Kok]https://youtu.be/uXXBIwW2Kok[/video]

Initiator001 said:

I have seen this.

"Darker" smoke can be caused by the paper liner burning or your view of the rocket in relation to the sun.

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Thanks. Makes sense, and I love hearing from an authority!

Different lighting conditions can change your perception too. On a bright clear sunny day with deep blue sky, the smoke may appear very white, but if it is overcast and not very bright, the same smoke may appear much darker.

size matters as well as how fast the rocket accelerates, a big motor puts out more smoke, and speed effects the smoke density. a black jack or a smokey sam look great lifting a saucer .
Rex

5x7 said:

Yes, here is a very old F40, no flame at all and dark smoke.

[video=youtube_share;uXXBIwW2Kok]https://youtu.be/uXXBIwW2Kok[/video]

Click to expand...

Holy Smokes, that doesn't look like a WL at all!!

Maybe you got a Black Lightning by mistake?

rcktnut said:

Holy Smokes, that doesn't look like a WL at all!!

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It is more rhan 20 years old, poorly stored, very oxidized. Took a bit of sanding to open the slot. The ones like that are for saucers only.

It could also have to do with moisture in the air.
When it's really cold the air most likely is very dry humidity wise.
Less water for the exhaust to react with......


JD

JDcluster said:

It could also have to do with moisture in the air.
When it's really cold the air most likely is very dry humidity wise.
Less water for the exhaust to react with......


JD

Click to expand...

Here in Georgia it is the other way around. When it is cold here, it's very humid.

My F20 flight at the same launch did the same thing to an extent, although I mostly thought it was due to the cloudy sky. This was a newish F20 as it had a built in molded plastic thrust ring, so I think it may just be that WL puts out darker smoke than other white propellents.

I've seen the F20 White Lightning produce darker smoke. I know that it's matter of pressure that makes smoke dark or white. Maybe the KN is on the low side with the F20's.

Here is an example. F20 Cloudy day. :surprised:
[YOUTUBE]rEwJCw2ISdk[/YOUTUBE]

The *old* original F20s had the slightly different 'crackling WL' propellant, which *did* tend to have grayish smoke along with the signature sound those motors made. IIRC there's an old photo of my Concorde boosting on one of these on the old Dr Sue site, and that definitely shows the non-white plume.

AstronMike said:

The *old* original F20s had the slightly different 'crackling WL' propellant, which *did* tend to have grayish smoke along with the signature sound those motors made. IIRC there's an old photo of my Concorde boosting on one of these on the old Dr Sue site, and that definitely shows the non-white plume.

Click to expand...

Yes. These also had a full diameter delay grain which contributed to the crackling and darker smoke. Miss those...they would get your attention, especially for an F motor!

I've seen this phenomena before with F and G WL but usually this happens on older reloads. Can't say I ever recall seeing that with a new one.

-Dave

marcusSRG said:

Yes. These also had a full diameter delay grain which contributed to the crackling and darker smoke. Miss those...they would get your attention, especially for an F motor!

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Yeah, I flew a couple of those, once in a homemade, 2-finned spinning rocket. Probably the coolest sounding small motor I've ever flown.

JDcluster said:

It could also have to do with moisture in the air.
Less water for the exhaust to react with......


JD

Click to expand...

I agree with this post. Humidity in the air.

AstronMike said:

The *old* original F20s had the slightly different 'crackling WL' propellant, which *did* tend to have grayish smoke along with the signature sound those motors made. IIRC there's an old photo of my Concorde boosting on one of these on the old Dr Sue site, and that definitely shows the non-white plume.

Click to expand...

Weren't those labeled as "Econojets"?

loopy said:

Weren't those labeled as "Econojets"?

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Yes, back when they were *really* ECONO-jets! Great price/Ns when they first came out, and the 'crackling WL' was a neato bonus. The best motors in slower boosting gliders, along with the counterpart G35's, which suffered too many CATOs at their end.

That's what I thought. I had remembered that the Econojets of old were slightly different from the standard WL...glad I wasn't nuts...lol