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Author Topic: How much nitro for Stunt and Sport Flying?  (Read 3263 times)

Offline frank mccune

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How much nitro for Stunt and Sport Flying?
« on: December 29, 2014, 02:06:56 PM »
     Hello:

     How much nitro should I use in my fuel for Stunt and Sport flying?


                                                                              Tia,

                                                                              Frank
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Offline Howard Rush

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Re: How much nitro for Stunt and Sport Flying?
« Reply #1 on: December 29, 2014, 02:34:02 PM »
At least 40%.  Why screw around?
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Offline Tim Wescott

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Re: How much nitro for Stunt and Sport Flying?
« Reply #2 on: December 29, 2014, 02:49:05 PM »
Quote from: Howard Rush on December 29, 2014, 02:34:02 PM
At least 40%.  Why screw around?

Howard, there are kinder ways to proselytize for electric power.

Frank:  As much as you need.  Depending on engine and plane you probably want between 5% and 15%.  If you have something to prove, mess with engines and planes until you can fly well with FAI fuel (0%).  If you have a very tediously underpowered engine, go up in nitro -- although, if you're getting above 25% in a 35 or bigger engine, then you probably want to investigate different engine options for that particular airframe.
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Offline Dennis Toth

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Re: How much nitro for Stunt and Sport Flying?
« Reply #3 on: December 29, 2014, 04:35:43 PM »
Frank,
A lot depends on what your source for purchasing fuel is. Try to get fuel that has at least 22% total oil for ABC, AAC, ABN (basically modern OS FP's, LA's etc.). If you are running an iron/steel engine (Fox, old OS Max, McCoy's, K&B green heads etc.) you want to get fuel with at least 25 - 28% total oil with at least a 50/50 castor/syn blend (high castor won't hurt up to 90%). For the iron/steel engines stay away from R/C fuels (Cool Power) as they don't run well in stunt (very low oil). With that said most modern engines run well on 10 -15% nitro depending on where you fly (higher altitude like Tucson, AZ run higher nitro). The iron/steel with be running at lower rpm and 5 - 10% nitro is fine.

Read Randy's Care and Feeding article at the top for more information.

Best,       DennisT
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Offline frank mccune

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Re: How much nitro for Stunt and Sport Flying?
« Reply #4 on: December 29, 2014, 05:41:33 PM »
      Hi All:

      Thanks for the replies!

      As I mix my own fuel, I am able to blend what I want.  I was thinking of the following mixes for my engines:

     Cast iron and steel engines will get 5% nitro, 24% castor 5% Klotz remainder alky.

     For my Brodak .25 I will mix one batch of 5%, 11% castor, 11% Klotz and the remainder alky. This is the only "modern" engine that I use! Lol

      In the Old Country in the 70's, I used FAI fuel with 29% castor oil in one loacation.  I paid $3.00 per Imperial gallon for pure USP Castor Oil in 1973.  The alky was free.  That fuel seemed to run very poorly especialy in .049 engines! In anothe area. I could only get Klots 100 and alky and I ran it at 29% oil.  This mix worked in the .19-.40 engines.

     I noticed that my friend was running LHS fuel that only contained 15%-17% total oil.  I suggested that he may want to add some Castor Oil and he said ,"Why? My engines run great on that fuel." What can I say? Lol

                                                           Stay well my friends,

                                                           Frank



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Offline Steve Helmick

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Re: How much nitro for Stunt and Sport Flying?
« Reply #5 on: December 29, 2014, 06:44:16 PM »
Quote from: frank mccune on December 29, 2014, 02:06:56 PM
     Hello:

     How much nitro should I use in my fuel for Stunt and Sport flying?


                                                                              Tia,

                                                                              Frank

What engines? How hot is it there, and how high is the altitude? Need more info that wot we got!  D>K Steve
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Offline Balsa Butcher

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Re: How much nitro for Stunt and Sport Flying?
« Reply #6 on: December 29, 2014, 11:28:46 PM »
How much Nitro for sport and stunt flying? Short answer:10%  8)
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Offline Chris Wilson

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Re: How much nitro for Stunt and Sport Flying?
« Reply #7 on: December 30, 2014, 02:20:55 AM »
Nitro equates to oxygen, the less of it above sea level the more you are going to need to keep a constant run.
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Offline Chris Wilson

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Re: How much nitro for Stunt and Sport Flying?
« Reply #8 on: December 30, 2014, 02:23:13 AM »
Quote from: Tim Wescott on December 29, 2014, 02:49:05 PM
  If you have a very tediously underpowered engine, go up in nitro .
Tim, what about upping the compression ratio and sticking with just FAI fuel?

Works with MVVS engines nicely.
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Offline frank mccune

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Re: How much nitro for Stunt and Sport Flying?
« Reply #9 on: December 30, 2014, 06:04:50 AM »
    Hi:

    Thanks for the replies!

                                                Stay well my friends,

                                                Frank
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Offline bob whitney

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Re: How much nitro for Stunt and Sport Flying?
« Reply #10 on: December 30, 2014, 03:06:01 PM »


  the other part of the equation is if it is a ball bearing engine or not  a BB,ABC needs the least oil of all a bushing engine needs more lube
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Offline Chris Wilson

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Re: How much nitro for Stunt and Sport Flying?
« Reply #11 on: December 30, 2014, 06:20:40 PM »
Quote from: bob whitney on December 30, 2014, 03:06:01 PM

  the other part of the equation is if it is a ball bearing engine or not  a BB,ABC needs the least oil of all a bushing engine needs more lube
Hi Bob,
Not sure what a nitro question has to do with oil content but 99% of all model engines have to suffer from a plain bearing big end and since that is the most stressed part of any engine I would use an oil content based around that.
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Offline Tim Wescott

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Re: How much nitro for Stunt and Sport Flying?
« Reply #12 on: December 30, 2014, 06:35:26 PM »
Quote from: Chris Wilson on December 30, 2014, 02:23:13 AM
Tim, what about upping the compression ratio and sticking with just FAI fuel?

Works with MVVS engines nicely.

Dunno about that -- but I'll believe you unless personal experiment proves otherwise.

It may not work with all engines, and it may not end up with an engine that has a nice "stunt run" -- but here again, I have no personal experience to go by.
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Offline Brian Hampton

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Re: How much nitro for Stunt and Sport Flying?
« Reply #13 on: December 30, 2014, 08:02:54 PM »
Quote from: Tim Wescott on December 30, 2014, 06:35:26 PM
Dunno about that -- but I'll believe you unless personal experiment proves otherwise.
Been there and done that (raising compression for FAI fuel). Standard (geometric) compression on the Enya 61 RE is 8.8:1 and gave a nice 4-2-4 run but after about 40 flights I raised comp to 12.4:1 which gave a broader 4 stroke range and better 4-2-4 break which I've stayed with ever since. Back to back testing on the test stand (enough time to swap head buttons) showed an increase in HP of 26% when peaked out. I've never used nitro in any engine so can't guess at how much nitro would be needed for a similar HP gain. What you DO get using nitro is a broader acceptable needle setting and is a simple way to adapt to different elevations. Something we don't really have to contend with in Australia :).

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