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OS .40 with DDD head=little power????

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Old 05-22-2018, 02:31 PM
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franchi
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Default OS .40 with DDD head=little power????

I checked my OS .40 FS with a DDD head and 3.3.3. fuel and recorded 8,800 rpm with an 11-6 prop. This works out to .42hp which is less than a Fox .35 Stunt produces. Do your results with DDD heads mirror mine?

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Old 05-23-2018, 01:04 AM
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Originally Posted by franchi View Post
I checked my OS .40 FS with a DDD head and 3.3.3. fuel and recorded 8,800 rpm with an 11-6 prop. This works out to .42hp which is less than a Fox .35 Stunt produces. Do your results with DDD heads mirror mine?

Cheers,

franchi
I guess that you mean 1/3 each of Castor, Ether, and Kero. I wouldn't expect stellar RPM on that fuel anyway. Why not try 20% Castor, 30% Ether, and 50% Kero, and add 1 to 2 % of Amsoil Cetane boost to that mix?
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Old 05-23-2018, 05:57 AM
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I would agree. Modern engines should have modern fuels. I use 23% castor, 31% ether, 2% amsoil Cetane Boost, and balance balance kerosene or Jet A. I have an old beat up K&B .45 that turns a 13x6 APC at 9,200 and an ST .45 that turns the same prop at 9,900 with a stock carb. I wouldn’t expect a .40 to do as well, but based on my presumptions, that .40 is down on power.
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Old 05-23-2018, 07:19 AM
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franchi
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Hello Diesel People:

Thanks for the prompt replies.

I used the 3 3 3 mix just to use it up as it was one year old and was mixed to be used as a break in fuel on the bench. Why did 333ever become popular?

I have been using 30either 25 castor Amsoil 1.5 additive remainder kero for flying. That mix has worked well for me in the past.

The question the use of Shell's Aero Shell oil dates back to more than 3 decades I used Aero Shell for oil in my Diesel engines when I could not find Castor Oil for sale. It was recommend back in the day for use in Diesel fuel. Since then, I have only used castor oil. The Aero Shell was purchased at a small airport. It was the ONLY oil used at that airport due to it being the best oil to be used in samall plane engines. Perhaps it is a mineral oil that leave vey little residue in the combustion chambers.

Has anybody used a blend of synthetic oil and castor oil in their Diesels to help to provide "clean engines?" I am running G20-.15D, MVVS D7, Fox .15 with DDD head, ST G21-35 with a DDD head and the OS .40. The ST 35 is a great engine as both DDD and glow. Do not hand flip this as a Diesel unless you want a hook installed where your fingers and/or hand once resided. Lol

In the past, I have read instructions that are issued with new Diesel engines that call for 20% castor oil. The kero is supposed to add a bit of lubricity to the mix to permit running a low oil content. However, I have seen this idea refuted as not being true. ???????

Enough for now as it is time to go and fly my two ST G20 15D powered Flite Streaks. That is a great combination for fun flying. It is too jumpy for good stunt patterns. Perhaps some nose weight would help. After that, I will fire up my Tom Tom that is powered by a MVVS D7 .15. That is a great flying combination. I just remembered that I built that plane circa 1980!!!! Lol

Thoughts/suggestions?

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Old 05-23-2018, 03:15 PM
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Traditional Diesels using Ferrous piston/liner systems need more oil. Modern tapered/plated
bore engines do not need the extra oil as the platings serve as a “slick” alternative to Ferrous parts. You would not use 25-33% oil in an ABC glow plug engine for the same reason you wouldn’t in an ABC Diesel. Ferrous pistons are a different animal.
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Old 05-23-2018, 06:11 PM
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A few years ago our regular supply of "castor" oil, Castrol M was terminated by the manufacturer. We can get what seems to be "Veterinary" Castor. Very good quality, good price, and satisfactory in every way. Some of us started experimenting with the "fortified" castors available in Bike and Karting stores. As a group we are heavy diesel users. Mostly we don't have any problem with coking up in our engines. For those who do I'd be looking at the quality of the Kero rather than the oil and perhaps not running the engines so hard (overcompressed?). I've been running 15% of the Maxima modified castor in my Profi K-12/15 Oliver Tiger diesel and the manufacturer suggest 12% as being adequate. Runs are usually no longer that about 130 second at any time with a brief "cool down" between them. It has an Iron piston/Chromed Steel liner. For the c/l combat version they recommend 20%. For general use I'd go for 20% oil for a twin Ballrace engine.

Last edited by qazimoto; 05-23-2018 at 08:37 PM.
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