Author Topic: Fuel spray around venturi (Read 4375 times)

Tim Wescott · « **on:** June 14, 2014, 06:04:23 PM »

OK. The real problem that I'm suffering from is that the new VP Racing/Powermaster fuel is dyed this really nifty purple color, and it's dying my airplane purple.

While I'm waiting for VP to tell me that they have no plans to fix this (and possibly giving me an instruction sheet on setting the mixture in an RC plane), I'm wondering if I can't minimize the problem.

I'm flying on an OS LA 46, and it sprays a LOT of fuel out of the venturi in normal operation. I can tell this by looking at the right side of my plane, which has kind of become a color chart of Where the Raw Fuel Lands.

If I were to make a really long venturi for the engine would it reduce this effect? If it did, would it muck up my nice stunt run? Is there any other way to reduce the amount of fuel spew from a venturi without mucking up the engine run?

Thanks.

Dave_Trible · « **Reply #1 on:** June 14, 2014, 06:26:17 PM »

Tim a velocity stack on the Venturi shouldn't do damage to your stunt run. The old panty hose/ O ring intake filter trick might help. While burping my .76 last week it backfired through the Venturi and blew a 3/8" hole right through the hose. But if the airflow is going the desired direction most fuel blowback should be slowed with the hose.

Dave

Tim Wescott · « **Reply #2 on:** June 14, 2014, 06:35:18 PM »

Quote from: Dave_Trible on June 14, 2014, 06:26:17 PM

Tim a velocity stack on the Venturi shouldn't do damage to your stunt run. The old panty hose/ O ring intake filter trick might help. While burping my .76 last week it backfired through the Venturi and blew a 3/8" hole right through the hose. But if the airflow is going the desired direction most fuel blowback should be slowed with the hose.

It's already got the panty hose filter (or at least fine nylon net) -- it's got the big stock (8mm?) venturi, with a stack of panty hose filters to tune the run.

D'ya think a velocity stack will help the problem, though? Or will I just end up doing a bunch of work for nothing?

On the bright side, this does give me an excuse to paint my next airplane a nice intense purple.

Dave_Trible · « **Reply #3 on:** June 14, 2014, 06:42:27 PM »

Might cut it a little..... But purple is nice.

Dave

Mark Scarborough · « **Reply #4 on:** June 14, 2014, 07:29:31 PM »

Tim,, interesting you should mention this,, Not sure if I mentioned it to you in Salem, but I am using the new VP GMA as well,, and my Avenger,, which is painted in Urethane clear,,,, is showing some light coloration from the fuel as well,, it kinda pissed me off,,

when and if you hear from them please let me know,,
better yet,, give me the contact information,, I will write an email as well,,

My Avenger is my baby,, especially after VSC when it was awarded pilots choice,, I really hate having it become stained by fuel pigments,,

Tim Wescott · « **Reply #5 on:** June 14, 2014, 08:11:20 PM »

Quote from: Mark Scarborough on June 14, 2014, 07:29:31 PM

Tim,, interesting you should mention this,, Not sure if I mentioned it to you in Salem, but I am using the new VP GMA as well,, and my Avenger,, which is painted in Urethane clear,,,, is showing some light coloration from the fuel as well,, it kinda pissed me off,,

when and if you hear from them please let me know,,
better yet,, give me the contact information,, I will write an email as well,,

My Avenger is my baby,, especially after VSC when it was awarded pilots choice,, I really hate having it become stained by fuel pigments,,

This is their tech support page, with an email form:

http://www.powermasterfuels.com/index.php?option=com_contact&view=contact&id=1&Itemid=6

This is the email address on that page (which is also the email on their sales page):

tommy.porfirio@vpracingfuels.com

I already mentioned that this isn't just an issue in pride in the finish, but a matter of losing points in competition. I think it would really help if you could write to them too, particularly if you have a URL to a news report of you getting that pilot's choice award.

And, of course, any other slime fliers who don't want their airplanes to turn purple in places.

Balsa Butcher · « **Reply #6 on:** June 14, 2014, 09:35:53 PM »

I was wondering if it was because they are dying it that color or have switched from Klotz Synthetic to Royal Purple Synthetic, a well know and popular purple colored racing oil. I don't like the new brew either.

Tim Wescott · « **Reply #7 on:** June 14, 2014, 09:43:38 PM »

Quote from: Balsa Butcher on June 14, 2014, 09:35:53 PM

I was wondering if it was because they are dying it that color or have switched from Klotz Synthetic to Royal Purple Synthetic, a well know and popular racing oil. I don't like the new brew either.

I hope not -- I'd imagine that they'd be more willing to change if it's a dye they're adding than if it's a more integral part of the mix, like the oil.

I'm not going to buy more of that fuel unless they can tell me it's not purple. I'm not sure what I'll do instead -- probably buy something that's 18% oil and add castor -- but I'm not going to gunk up my airplanes.

Balsa Butcher · « **Reply #8 on:** June 14, 2014, 10:20:29 PM »

If it's purple dye and not an integral part of the mix we should all contact Powermaster them and ask them to leave the dye out of their GMA and Ro-Jett lines of fuel. It's a small company and as we can safely say that 100% of C/L modelers don't want purple it may help...worth a try anyway.

Tim Wescott · « **Reply #9 on:** June 14, 2014, 10:25:17 PM »

Quote from: Balsa Butcher on June 14, 2014, 10:20:29 PM

If it's purple dye and not an integral part of the mix we should all contact Powermaster them and ask them to leave the dye out of their GMA and Ro-Jett lines of fuel. It's a small company and as we can safely say that 100% of C/L modelers don't want purple it may help...worth a try anyway.

We'll see what they say.

If they are made to understand the undesirability of purple-stained airplanes, they may even reconsider the oil choice.

Mark Scarborough · « **Reply #10 on:** June 14, 2014, 11:23:21 PM »

sent an email to them we will see what the response is
I was wondering if I was the only one seeing this. Fortunatly its pretty much confined to the bottom of the Avenger,, and its pretty subtle still,, but it pisses me off something royally,,

Tim Wescott · « **Reply #11 on:** June 15, 2014, 01:02:13 AM »

Quote from: Mark Scarborough on June 14, 2014, 11:23:21 PM

sent an email to them we will see what the response is
I was wondering if I was the only one seeing this. Fortunatly its pretty much confined to the bottom of the Avenger,, and its pretty subtle still,, but it pisses me off something royally,,

It's getting pretty dramatic on Sister Jenny. It's about as dark now as the blue sky -- if the blue sky were purple. So whatever the dye is, the effect is cumulative. I'll try to post a picture tomorrow.

Gerald Arana · « **Reply #12 on:** June 15, 2014, 07:57:45 AM »

I have enough problems with "Hanger" rash.........

And now purple stained planes?

I don't think so.

I won't be buying any "Powermaster fuel" anytime soon.

Thanks for the information and hopefully they will "Get'er fixed!"

Tight lines, GA

Dick Pacini · « **Reply #13 on:** June 15, 2014, 12:42:01 PM »

Are you sure it is spraying out of the venturi? I have seen worn engines blow raw fuel from the front crank bushing. Sometimes hard to see because of prop blast.

Tim Wescott · « **Reply #14 on:** June 15, 2014, 12:58:57 PM »

Quote from: Dick Pacini on June 15, 2014, 12:42:01 PM

Are you sure it is spraying out of the venturi? I have seen worn engines blow raw fuel from the front crank bushing. Sometimes hard to see because of prop blast.

It occurred to me after I got this thread rolling that this may, indeed, be the case.

One way or another it wouldn't be nearly as serious a problem if the @#$% fuel weren't dying the airframe, though.

Mark Scarborough · « **Reply #15 on:** June 16, 2014, 06:18:20 PM »

well I recieved a phone call from VP fuels today regarding my email,,
the gentlrman was very cordial and it is in fact a dye they use

they will make all GMA fuel with no dye from this point on,, we discussed how to remedy my (our) situation and when they make up the next batch he will call me and perhaps either replace or make me a good deal on fuel with no dye,,

so, they are responsive and listening,, all good things

RandySmith · « **Reply #16 on:** June 16, 2014, 06:27:16 PM »

Same thing happened years ago with a RED fuel, it caused a lot of grief

Randy

Brett Buck · « **Reply #17 on:** June 16, 2014, 06:57:34 PM »

Quote from: RandySmith on June 16, 2014, 06:27:16 PM

Same thing happened years ago with a RED fuel, it caused a lot of grief

Actually, several fuels. Red Max was one that added a lot of dye and made everyone's airplane pink, a LONG time ago.

Brett

Brett Buck · « **Reply #18 on:** June 16, 2014, 06:59:08 PM »

Quote from: Mark Scarborough on June 16, 2014, 06:18:20 PM

they will make all GMA fuel with no dye from this point on,, we discussed how to remedy my (our) situation and when they make up the next batch he will call me and perhaps either replace or make me a good deal on fuel with no dye,,

so, they are responsive and listening,, all good things

That would be Tommy Profirio, good guy. I talked to him today on the same topic, and I will be getting some RO-Jett 10% with no dye next week some time.

Brett

Balsa Butcher · « **Reply #19 on:** June 16, 2014, 08:20:25 PM »

Yes!!!!

Mark Scarborough · « **Reply #20 on:** June 16, 2014, 09:55:32 PM »

Brett,
he seemed to clearly understand our portion of the hobby and appearance, and how important finishs are to us,

I could not recall his name,, but it was great and very suprising to get that call this morning,,

awesome guy