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Author Topic: Replicating RO-Jett fuel  (Read 1750 times)

Online Brett Buck

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Replicating RO-Jett fuel
« on: May 12, 2019, 07:52:53 PM »
Of course, Powermaster has long since discontinued "RO-Jett" fuel. This fuel was not "Required" for RO-Jett engines, and it works very well in other engines, and is a useful variant - which substantially less boost/brake on most engines that the Powermaster RC  Sport fuel (currently called "Air")

  They wouldn't tell me for sure what was in it, aside from 22% total oil, 5% castor/17% synthetic, which is the same as Richard had requested originally. Since it was discontinued, David and I had tried various adjustments to Powermaster 10% "Air" to get it to run the same. David added some castor and some Klotz, which he says replicates the effects, but didn't work the same for me, althougth it was also a useful adjustment to the engine run.

   I think I have come a lot closer to the original - add ~4% Klotz KL-198 "Light Techniplate" - a lower-viscosity version of original Techniplate. This is a pure synthetic like Techniplate but substantially lower viscosity. I have run *many* flights with 10% RO-Jett, and swapped back and forth many times. The modified fuel requires the same needle shift, the same difference in launch revs (higher) as switching to "real" RO-Jett (which I still have), and feels the same in air, particularly, feels "stiffer" in the corners, as opposed to falling off, then breaking, and not backing off at some inconvenient moments.

    Note that this should also permit you to make your own "15% RO-Jett", for hot weather and higher altitudes.

    Brett

Offline Lauri Malila

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Re: Replicating RO-Jett fuel
« Reply #1 on: May 13, 2019, 09:34:12 AM »
I wonder what the difference is between the #198 and #189 Heliglow..? They are both low viscosity and Iíve been very happy with the #189. Have you tried it?
I know Randy is against those thin oils due to surface issues but I think engine run is so much better that it would be silly not to take the advantage.
I more or less eliminated the wear by super-finishing and diamond coating all crucial steel surfaces. L

Offline RandySmith

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Re: Replicating RO-Jett fuel
« Reply #2 on: May 13, 2019, 01:09:21 PM »
I wonder what the difference is between the #198 and #189 Heliglow..? They are both low viscosity and Iíve been very happy with the #189. Have you tried it?
I know Randy is against those thin oils due to surface issues but I think engine run is so much better that it would be silly not to take the advantage.
I more or less eliminated the wear by super-finishing and diamond coating all crucial steel surfaces. L

Hi Lauri

Randy is against  using  ALL  low viscosity oil, it WILL result in excess  wear over the oils we use  now , a combination of oils  could  be  OK

Randy

Offline Brian Hampton

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Re: Replicating RO-Jett fuel
« Reply #3 on: May 13, 2019, 10:55:51 PM »

I more or less eliminated the wear by super-finishing and diamond coating all crucial steel surfaces.
I've wondered who'd be the first to try diamond coating in model engines. Have you done that with a ringed engine or just the crankshaft?

Offline Lauri Malila

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Re: Replicating RO-Jett fuel
« Reply #4 on: May 14, 2019, 12:01:28 AM »
I've wondered who'd be the first to try diamond coating in model engines. Have you done that with a ringed engine or just the crankshaft?

Brian,

Robbie has done it with f2c for a long time allready. Main place is rod big end, in small end it won't last well in team racing.
For me both crankpin and piston pin are ok.
I don't really know what part of ring I should coat, and I think it's too big risk to send a finished ring abroad to be handled by someone else. But ring is not important, I have no problems with them.
I think next I'll also coat the piston, diamond sticks well to our piston alloy and it really reduces friction. L

Online Dave Hull

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Re: Replicating RO-Jett fuel
« Reply #5 on: May 14, 2019, 12:56:29 AM »
Diamond also has fabulous thermal conductivity. That would seem to be a benefit for use in engines, too.

Dave

Offline Lauri Malila

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Re: Replicating RO-Jett fuel
« Reply #6 on: May 14, 2019, 04:40:03 AM »
Diamond also has fabulous thermal conductivity. That would seem to be a benefit for use in engines, too.

Dave

Yes, but I donít know what difference a micron thick layer really makes. L

Offline T.J. Vieira

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Re: Replicating RO-Jett fuel
« Reply #7 on: May 14, 2019, 06:30:57 AM »
are you guys talking about PVD coatings?

VW used them on tappets for high pressure fuel pumps as a wear surface/"lubricity enhancing" surface.

was supposed to be a lifetime deal, but they only last about 35k-40k miles in the 2.0 turbo engines, then failure mode is the pump piston rod poking through the tappet, and taking out the cam lobe....  at first they tried blaming improperly hardened cams ("a" and "b" cams), but they all do it in the long run.  i change mine out every 25k, and it's already wearing through the coating.

but, that's a bunch of up and downs (tri-lobed cam)!

we also use them in our grinding machines at work, but for dressing grinding wheels.  quite a catch all process/material!

Offline Lauri Malila

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Re: Replicating RO-Jett fuel
« Reply #8 on: May 14, 2019, 06:47:49 AM »
I donít know, what we have is called DLC, diamond like carbon. Itís a physical deposit, done by accelerated graphite plasma, in vacuum. Then there is also different gradient layers, depending on base material. Usually sputtered tungsten or titanium.
Itís difficult to compare a VW and stunt engine. Itís not a miracle product that fixes all problems like in some TV-shop.
But main thing is that when done correctly, it really helps. L

Offline T.J. Vieira

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Re: Replicating RO-Jett fuel
« Reply #9 on: May 14, 2019, 07:24:46 AM »
yup, same coating (or at least style).

true, two totally different applications (well, three if you include grinding machines).

Offline RandySmith

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Re: Replicating RO-Jett fuel
« Reply #10 on: May 14, 2019, 08:10:01 AM »
Brian,

Robbie has done it with f2c for a long time allready. Main place is rod big end, in small end it won't last well in team racing.
For me both crankpin and piston pin are ok.
I don't really know what part of ring I should coat, and I think it's too big risk to send a finished ring abroad to be handled by someone else. But ring is not important, I have no problems with them.
I think next I'll also coat the piston, diamond sticks well to our piston alloy and it really reduces friction. L

The main place i see  where  thin viscosity oils  fail in stunt engines is the  top , small end of the  rod, after that it is the crankpin, and  then the  wrist pin

Randy

Online Brett Buck

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Re: Replicating RO-Jett fuel
« Reply #11 on: May 15, 2019, 03:34:05 PM »
I wonder what the difference is between the #198 and #189 Heliglow..? They are both low viscosity and Iíve been very happy with the #189. Have you tried it?
I know Randy is against those thin oils due to surface issues but I think engine run is so much better that it would be silly not to take the advantage.
I more or less eliminated the wear by super-finishing and diamond coating all crucial steel surfaces. L

   I wouldn't say, in my case, that it's necessarily better, just different.

    I am not concerned about "wear" in the conventional sense, even without diamond coatings. The AAC/ABC/ABN engines that I am likely to use are more than adequately durable with any oil I am likely to run in them. I have worn out exactly one engine in the past 35-ish years -  after an insane number of flights  - and using more castor than I would today. Any other engine problem I have had was not with wear, but with either FOD or non-wear-related failures.

    I figure adding 5% *more* oil to a fuel I would have happily run unaltered can't make it worse from a wear perspective.

     Brett

Offline gordon tarbell

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Re: Replicating RO-Jett fuel
« Reply #12 on: May 16, 2019, 12:45:40 PM »
The 189 heli light synthetic has an anti foaming agent added and is slightly lighter in viscosity than the 198
Gordon Tarbell AMA 15019

Offline FLOYD CARTER

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Re: Replicating RO-Jett fuel
« Reply #13 on: May 16, 2019, 02:08:45 PM »


I'm running two RO-JETT 61 engines.  I use only SIG 10-10-10 because it's available.  Should I add anything to the stock fuel?  Seems to run OK straight from the jug.
« Last Edit: May 16, 2019, 09:27:48 PM by FLOYD CARTER »
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Online Brett Buck

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Re: Replicating RO-Jett fuel
« Reply #14 on: May 16, 2019, 02:25:34 PM »
There has been an eternity of discussion about the "right" fuel.  Here we go again.

  Sorry this topic is so darn tedious, for you.  But other people also fly model airplanes, not just you. They might benefit from the results of the experiment, or learn something from it.

    Brett

 

   

Online Brett Buck

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Re: Replicating RO-Jett fuel
« Reply #15 on: May 16, 2019, 02:28:50 PM »
The 189 heli light synthetic has an anti foaming agent added and is slightly lighter in viscosity than the 198

  Anti-foaming agent?  That sounds a bit ominous to me, potentially providing a source for "tater" material. I don't know about that for sure, because I didn't try it.

    Brett

Online peabody

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Re: Replicating RO-Jett fuel
« Reply #16 on: May 16, 2019, 03:38:45 PM »
VIP does list 5/22 and 10/22 GMA blend, half synthetic and half castor.
https://vpracingfuels.com/rc-fuels/#aviation

The problem here is that there aren't enough still using engines to justify a pallet


Offline gordon tarbell

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Re: Replicating RO-Jett fuel
« Reply #17 on: May 16, 2019, 04:04:48 PM »
If memory serves me correctly , I got this info from lab tech not sales person working at Klotz.
Gordon Tarbell AMA 15019

Offline Lauri Malila

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Re: Replicating RO-Jett fuel
« Reply #18 on: May 16, 2019, 04:13:18 PM »
  Anti-foaming agent?  That sounds a bit ominous to me, potentially providing a source for "tater" material. I don't know about that for sure, because I didn't try it.

    Brett

I flew last summer with #189, no issues with plugs (Merlin #2004). My plug problems (I don't know exactly what them Taters are, but I had issues with some sort of resin buildup near the end of filament) were allways related to high efficiency, when I used about 3oz./flight (.77 engine). No matter what oil I used, and I never use anti foam additives.
With massive 4oz. consumption plugs seem to last forever.

Floyd,

I don't really follow the things that repeat themselves forever, but instead I try to make things that make sense and try to find logical solutions to problems. This thinner oil is one of them. High efficiency is another. Both of them cause problems in engines that represent classical technology, so the logical step was to improve mechanical and thermodynamical stability (tribology, integral AAC-R, etc.).
So at least for me, the subject is not yet beaten to death. L



Online Brett Buck

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Re: Replicating RO-Jett fuel
« Reply #19 on: May 16, 2019, 05:14:05 PM »
I flew last summer with #189, no issues with plugs (Merlin #2004). My plug problems (I don't know exactly what them Taters are, but I had issues with some sort of resin buildup near the end of filament) were allways related to high efficiency, when I used about 3oz./flight (.77 engine). No matter what oil I used, and I never use anti foam additives.

  That's it, a deposit on the element, that almost always starts on the pigtail end of the glow plug element, adjacent to the weld. Presumably, the rest of the element is hot enough to burn it off, and the glow plug body is too cool to form it in the first place, but somewhere in between it has just the right conditions.

   I always associated it with silicone anti-foaming agents, because it's looks like a tan polymer/plastic droplet when you scrape off the surface, and it was enhanced by adding Armor-All.

    Brett

Offline Lauri Malila

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Re: Replicating RO-Jett fuel
« Reply #20 on: May 17, 2019, 04:44:49 AM »
Aha. Same thing.
Only time I had zero issues with taters was with Retro engines and the recommended KC-2 Soviet plug. KC filament is very soft (less rhodium) and propably less pure than, say, Thunderbolt or Merlin filament.
Also, allready after a few flights the KC filament looks like sandblasted while ĒbetterĒ ones stay shiny.
Perhaps that is the secret, some sort of corrosion that keeps the surface clean. The KC last very very long time, sometimes allmost a season per plug:)

L

Online Brett Buck

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Re: Replicating RO-Jett fuel
« Reply #21 on: May 17, 2019, 05:19:05 AM »
Aha. Same thing.
Only time I had zero issues with taters was with Retro engines and the recommended KC-2 Soviet plug. KC filament is very soft (less rhodium) and propably less pure than, say, Thunderbolt or Merlin filament.
Also, allready after a few flights the KC filament looks like sandblasted while ĒbetterĒ ones stay shiny.
Perhaps that is the secret, some sort of corrosion that keeps the surface clean. The KC last very very long time, sometimes allmost a season per plug:)

     My plugs seem to last indefinitely.  I have never had a tater of any consequence running my current brand of fuel (Powermaster, any variety).  At least a year or more, even in years I flew a lot. Other brands of fuel, as little as 20-30 flights at times. SIG brand seemed to be far an away the worst for this, although it's fine otherwise.  I use Thunderbolt 4-Cycle plugs, but I never noticed it was any better or worse with any of the plugs I tried.

   All of my RO-Jetts are much less prone to it than my PA61 was, and the PA61s were not all the same. My particular PA61 was not too bad, running SIG, I might get around 50 flights with decent power.  A nominally-identical engine that I borrowed from David Fitzgerald's dad Bill was far and away the worst, it would start losing power in as little as 10 flights, although it was still more than sufficient out to about 20-25 flights.

    I just run Powermaster and forget about it, it's just a non-issue with either the RC Sport fuel (10% "Air", 15% "Air"), 10% RO-Jett, or YS 20/20. I haven't run the modified "Air" long enough to tell, but I would be astonished if it wasn't OK in this regard.  I never had any tater issue with 10% GMA, but it doesn't work for other reasons with my setup. I have done essentially no testing in recent years with off-brand fuels like the Morgan fuels, Wildcat, Byron, etc.

      Brett

Offline FLOYD CARTER

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Re: Replicating RO-Jett fuel
« Reply #22 on: May 19, 2019, 11:12:44 AM »
The topic was about RO-Jett fuel.  My observation was that there seems to be many opinions concerning the "right" fuel.  I questioned whether my fuel was optimum for the RO-Jett.
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Online Brett Buck

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Re: Replicating RO-Jett fuel
« Reply #23 on: May 19, 2019, 06:51:41 PM »
The topic was about RO-Jett fuel.  My observation was that there seems to be many opinions concerning the "right" fuel.  I questioned whether my fuel was optimum for the RO-Jett.

    I said right in there that it wasn't "necessary" and that it was a tuning tool. I am not trying to get you to change your fuel, but to provide a solution to those who liked the discontinued fuel and wanted to replicate the effects. Hence the use of the work "replicating" in the title.

    No one is compelled to take any advice they get from anyone. David and I have spent a fair bit of time on this topic, I think I found a good solution, so I posted it for others to use. Other people had other inputs, some on-topic, and some off-topic but interesting. I don't and they don't have to justify it to anyone, use the information, or don't.

   Changing the oil content, particularly the change from the Powermaster R/C sport fuel and RO-Jett fuel, where essentially the only change is the quantity of synthetic oil, markedly changes the run. As described here:

https://stunthanger.com/smf/engine-set-up-tips/everything-matters/msg275948/#msg275948

  This provides a way for others, who can no longer get the fuel mentioned, to experiment with the effects described. I cannot tell anyone whether those effects are going to be beneficial or not.

    Brett

Offline Reptoid

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Re: Replicating RO-Jett fuel
« Reply #24 on: May 21, 2019, 11:58:36 PM »
I am quite sure that you could get some "RO-Jett" formula fuel from Randy Ritch of "Ritches Brew".Since Powermaster is no longer making it and Randy is friends with Dubb Jett (they race pylon together and Randy uses Jett engines), I think he would be happy to replicate it for you. He will actually make any brew you want on special order. He supplies most of the "supplied fuel" at pylon races and F2D combat contests as a "sponsor" y1
Regards,
       Don
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Offline Jim Damerell

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Re: Replicating RO-Jett fuel
« Reply #25 on: May 22, 2019, 07:49:50 AM »
VP sells a fuel called "Mean Green", that is 18 percent synthetic. When I called, before last season, they claimed Richard Oliver was using it. I bought some, but have yet to try it. If the motor runs hot, or the exhaust is not oily enough I will add some Bean Oil.

Offline Lyle Spiegel

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Re: Replicating RO-Jett fuel
« Reply #26 on: May 24, 2019, 06:14:28 PM »
In reading the thread I saw mention of DLC coatings. This material was developed as part of R&D to find ways to produce synthetic diamond and for extending performance & uselife of steel or carbide cutting tools. Recall from HS chemistry that "diamond" is a particular form of Carbon (as is graphite) Thus, when heated to sufficient temperature DLC will either transform to "graphite"  and  in presence of oxygen it will burn.  It is known that DLC films disintegrated at approx 350įC, (662F) showing typical graphitic transformation and oxidation behavior. Thus, I am uncertain of how DLC can provide benefit in our engines unless local metal temperature where piston is sliding on cylinder wall is well below that limit. (Does anyone ever determined what is actual temps?) As point of reference 660C is approx MP of Aluminum, so not hard to imagine 350C inside the cylinder.

please note, I am not intending to create any arguments. Before retirement I spent my career as a Metallurgist/Materials Engineer working on hot section materials for aircraft engine gas turbine and liquid fuel rocket engines. ( No rocket scientist remarks please, LOL)
Lyle Spiegel AMA 19775

Offline Lauri Malila

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Re: Replicating RO-Jett fuel
« Reply #27 on: May 25, 2019, 01:33:27 AM »
Lyle,

In in temperatures you mention, the steels we use start to loose their properties. In bottom end of engines, things don't get so hot, well under 100įC during running.
The wrist pin has been a weak point in racing engines, in our use it seems to cause no problems, especially with our piston scavenging. L

Online Brett Buck

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Re: Replicating RO-Jett fuel
« Reply #28 on: May 25, 2019, 09:18:14 AM »
VP sells a fuel called "Mean Green", that is 18 percent synthetic. When I called, before last season, they claimed Richard Oliver was using it. I bought some, but have yet to try it. If the motor runs hot, or the exhaust is not oily enough I will add some Bean Oil.

    I would suggest not using that. Ricahrd told me he as using it, but that it caused the engine to tighten up after 3-4 flights, at which point he had to *remove the piston and sand some green deposit off with sandpaper*! There may have been other issues, but that put me off it.

      Brett

Online Mike Greb

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Re: Replicating RO-Jett fuel
« Reply #29 on: June 01, 2019, 07:39:02 PM »
My RO-Jett 65 runs great on stock Cool Power 10%.  I started using Powermaster when the LHS (RIP) had Powermaster cheaper than Cool Power.

Offline Steve Fitton

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Re: Replicating RO-Jett fuel
« Reply #30 on: June 19, 2019, 02:06:03 PM »
This is good to know.  I remember a discussion on the floor of the 180 building about reverse engineering RoJett blend but not much since then.  If sig continues to be unavailable I'll have to test this out.
Steve

Online Brett Buck

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Re: Replicating RO-Jett fuel
« Reply #31 on: June 20, 2019, 01:46:42 AM »
This is good to know.  I remember a discussion on the floor of the 180 building about reverse engineering RoJett blend but not much since then.  If sig continues to be unavailable I'll have to test this out.

   I am not sure why anyone would still be using SIG at this point, Powermaster "Air" (RC Sport Fuel) is essentially the same thing, minus the taters.

     Brett

Offline RandySmith

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Re: Replicating RO-Jett fuel
« Reply #32 on: June 20, 2019, 02:06:40 PM »
The  SIG  4 stroke  snth  fuel works  very well, I add  2.5 ounces oil and  1  ounce  Aero-1 in it

Randy

Offline Steve Fitton

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Re: Replicating RO-Jett fuel
« Reply #33 on: June 21, 2019, 06:42:33 PM »
Laziness is why I still run Sig. Nobody left around here selling Powermaster so it's a long drive to Richmond where the Hobbytown sometimes has PM in stock. Sig champion mixed half and half with Sig synthetic doesn't form taters, at least over 100 flights or so. All I see on plugs is a brown discoloration after a bunch of flights.
Steve

Offline FLOYD CARTER

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Re: Replicating RO-Jett fuel
« Reply #34 on: July 02, 2019, 01:52:55 PM »
I checked my glo plug after a flight with a poor engine run.  I actually found a "tater", as previously described.  I carefully scraped it right off, and the glo plug looked nice and clean, so I tried it again.  Worked great.
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