I had the opportunity to try some new Brodak fuel this past weekend. I headed out to fly with the Skylarks of Sharon and upon leaving, I noticed my supply of Powermaster 10/22 was low.
At the hobby shop (Brodak’s), I saw some new fuel, 10% nitro, 23% 50/50 lube so I decided to give it a try. Since I had three airplanes with totally different powerplants to try, I figured it would be a good basic indicator.

Argus/SAITO .30. Weather one day warm and pleasant, the next day very hot and humid. Seemed to run as well or a bit better than before. I did have it start backwards a few times but that was probably my fault. Exhaust residue was a bit cleaner. It ran the same BOTH days without changing the needle setting.

Cardinal ARF/OS non-Surpass .40. Weather very hot and humid. Not so good for this powerplant. The engine likes a lot of nitro (I normally run 20/20) and the power was noticeably down.

Stinger/Fox .35. Same hot and humid weather. WOW!! The runs were considerably better. It seemed to run more uniformly and the power definitely felt better. After a really “spirited” flight, the engine just seemed warm and had that great snappy feel when flipped.
I should mention that this Fox is completely stock right down to the needle valve – never been disassembled. It runs as well or better than any modified Fox I’ve ever seen. I adjusted the needle back in May and have not touched it since. A well know Fox owner at Brodak’s said it was one of the absolute best running Foxes he had ever heard.

If this past weekend is any indication of the potential , I will highly recommend the Brodak fuel for Fox .35s and modern 4-strokes. I will, of course, continue to test it in other engines.

Bob Z.

Hi, Bill - I would suggest calling the shop or sending an e-mail to Brodak.

I'm pretty sure there was a variety of blends.

Bob Z.

Lyle - I posted this somewhere else, a while back. It is my own experience but it convinced me of something I've always suspected - that 29% oil is just a waste.
I'm convinced that 22% will do no harm (I run it in virtually every engine I own) but there is an advantage to 29% - read on:

“For anyone curious about lubrication of a Fox .35, here’s an experiment that I did a few years back.
 
I had two identical Fox .35s, the first version with the fore-and-aft muffler lugs on the case. One was brand new in the box, the other had a lot of time on it. The head was totally encrusted with burned castor to where the screws were nearly covered. The piston was black. Compression was strong and there was virtually no slop in the front bushing. Although I bought it as such, I assumed that it had lived on a high castor diet. The only thing I did to it was to remove the baked on castor using Dave Gierke’s “Demon Clean”. A fine product.
 
I broke in the new engine in on Powermaster 5% nitro, 22%, 50/50 oil for approximately one hour. I then put both engines on a variety of different aircraft, switching them around from time to time. Both profile and inverted mounting. I tried a tongue muffler as well as a Fox muffler with the exhaust nipple cut off to enlarge the hole.
 
I ran both engines on the same Powermaster but with 10% nitro. I used the engines for two seasons accumulating hundreds of flights on each.
 
The piston of the used engine lightened up a bit but the compression NEVER changed – it always had a good “snap”. The new engine ran perfectly the entire time. Neither engine showed any adverse wear in the piston/cylinder fit or the front bushing. The piston of the new engine still looked new.
 
My only complaint on both was that they did not exhibit the classic Fox 2-4 break. On a whim, I ran some 5% nitro, 29% straight castor in the newer engine, which was then mounted in a Nobler. Instant classic 2-4 break – exactly as I remember. 
Switching back to Powermaster, the break went away.   
 
Anyone else have a similar experience? By the way, I still have both engines and they have excellent compression.  I would not hesitate to put either in a classic or old-time plane.
 
Bob Z.”
 

Kreth - you misunderstand. I am not using it because a particular manufacturer makes it. That has NOTHING to do with it. The manufacturers that I buy from also make 29% castor - I just stated that, in my opinion, it's a waste.

I use a particuler product because I'm confident that it works - simple as that.

Regarding  metallurgy and materials, I also use the same mixture in my 50s engines like my Atwood Triumph and K&B Glow-Torp .29 -  there has never been problem.
 
I plan to break in my new McCoy RR.29 and Dooling .29 with the same fuel and I'm 100% confident that it will not harm them.

The important thing is that we use what we feel best suits our needs.

Bob Z.

Hi - non taken.

I really believe the the important thing is that we use whatever works best for our particular needs.

It's interesting how things can work well in particular engines and fail in others.

At Muncie in 1997, I was having trouble with an OS Max-S.35, running 5/25 straight castor.
A friend recommended castor/synthetic blend. I tried it and the engine seized!
Took it home, freed it up and ran the straight castor for another two years.
My friend runs the same engine on the blend.
Go figure.

Bob Z.

"The fact that the break went away should be an indication that the engine is running hotter."
I must say that I'm puzzled on that one - please explain the rationale.

"What good is a Fox .35 that doesn't break?"
That statement puzzles me even more. 
Ever think that a 2-4 break could be useless in some aircraft?
My Stinger for example.

Bob Z.

"The fact that the break went away should be an indication that the engine is running hotter."
I must say that I'm puzzled on that one - please explain the rationale.

"What good is a Fox .35 that doesn't break?"
That statement puzzles me even more. 
Ever think that a 2-4 break could be useless in some aircraft?
My Stinger for example.

Bob Z.

The fact that you were running 22% but found 23% to run better should be an indication to you that you are not running enough oil in your fuel. My guess is that you would find 24% to run a little better than 23% and so on as far as the Fox is concerned. The high castor content helps dissipate heat. Excess heat will lean the engine and cause runaways.
There are Fox .35's that have been run on high castor fuel for 30 years and more. Some people run a few gallons through an engine and declare that the fuel causes no wear and that 29% oil must be a waste. Duke Fox and the hundreds of others after him that have up to 50 years of proof in the form of engines that have run literally drums of fuel through them must be wrong. I have a Fox .35 that has been running with the original piston & sleeve since 1978. I'm sure that some on this site have more years on their Foxes than that. When someone racks up 28 years or more on 22% 1/2 castor, let us know.   
Different strokes for different folks, but I would think that any aircraft that didn't have a use for the 2-4 break wouldn't have a use for the Fox .35 . I know that there are plenty of folks running them in their little racers on low oil content fuel, but they won't be running those for years and years.

Hi, Lou - I will be speaking to John today. I will ask him about custom blending.

For the record, what blend did you have in mind?

I would guess that if the quantities justify, he could do it.

Bob Z.

Hi, Lou - I'll definitley ask John for you.

I called him but he's helping Buzz's mom move today.

Bob Z.