EdwardN

iTrader: (1)

I am sorry, unfortunatelly both my PC's got "worm" and I need to clean them first, I belive I will do it this saturday and after that I will post pics. Now I am at work, can't do from here.

EVOLUTION

I have never seen anyone run without any nitro.How is the performance with only straight methanol?

Corse-R

Main problem of fuel without Nitro is that every engine will try it will be a b*tch to carb adj.

Many FAI (mostly F3A if not remember bad) are tuned for going only without a mere 5% of Nitro or No Nitro allowed at all, believe me, are a gross b*tch to tune the carb for performing fine, not for the newcomers.

The reason of higher flame temp and flame speed is interesting, but main duties of Nitro on the combustion chamber is to give Oxigen due to cracking method to the combustion and reduce a little the flame speed on the chamber, but too much nitro can slow too much the flame and start giving flames thru the stinger of your pipe.

One time I remembered that went to an exhibition and we forgot to carry the fuel, called to my brother to bring us some fuel, He carried a 5Litre can of pure Nitro. Engines started without plug heater and the flames were quite scary.

Engines got ruined after few seconds, but were quite spectacular.

EdwardN

iTrader: (1)

Perfect performance. Burning properties of methanol is mauch higher then nitro-meaning, vapor pressure, flash point etc.
As I sad before-runs cooler, leaner. Pick up the same or better, speed will check this weekend with radar, last time we were running it was too late and was no radar already. I love it, don't undertstand why people don't use it. Will figure out.

EdwardN

iTrader: (1)

As I know FAI and NAVIGA (for sure) do not allow any Nitro. For me very difficult to say if tunning is b..h, I don't have any problem at all. Actualy I tuned engine on the table and on the track just check temperature on bottom end. Ambient was 98 F and engine was 210. As I sad before need to check with radar, don't want to lie about top speed, seems for me was very good, but no real numbers.
As I know, the main reason to have Nitro in fuel is-nitro doesn't need that much oxigen to burn as methanol needs, so with smaller carb hole we suposely have more burning power with nitro. I am realy not clear about burning power, this is why I try to play with pure methanol. Back in Russia, we never have problem without nitro and power output was >>>>>>>!!!!!!!!!
Becuase of burnng properties of nitro you need to run engine with lower compression ratio and colder plug-I think there is some power is missing.
Abdsolutly, nitro give engine high flexobility and cover a lot of tunning mistakes, but this is supose tobe not issue.

modellor

Yep. Click,Dublin can back this up. He seen the power and speed of my 2.5yr old RB and I only ever run it on 5% Nitro.

Tuning is harder with less nitro but the engine does run better and longer without it. As for plugs - most people around here run RB or Novarossi No5 plugs. I tried them with not much luck. Engine wouldnt run perfect. In the end I went back to the plug I have always used (OS No3). When our weather is warmer I change to an OS No4 at the most.

click, dublin

Yes indeed, Modellor's RB is one quick puppy. 5% nitro, very interesting!

Just to annoy you guys some more:

I have two 7.2V stick packs which I ran in a Mardave Cobra for 3 years, kept them for another 4 years & now I'm using them in my Mugen starter box for the last 3 years. I use the starter box to start my MTX3 & MRX3 & they last a full day.

So . . . . 10 years old & still going strong.

I also have a throttle servo which I use in my MTX3. I've had it in 4 cars over the last 9 years & this is still going strong!!

I must admit I do not get many years from my engines. The longest I got from a MT-12 was about 3.5 gals.

My latest MR-12 seems to be running out of steam at about 1.5 gals, never had it over 240 temp.

We have alot of Saint's in Ireland and no snakes, maybe thats something to do with it!!!!

All the best

EdwardN

iTrader: (1)

As I mentioned before, there is a way to make engines run much more then 2-3 gallons. Try to follow procedure I explaned before, you will be happy.

EdwardN

iTrader: (1)

Hey guys, no more topings to discuse about the engines?

Data

ok, i have a question for you then.

what is the purpose of the dome chamber on the button head ? and how it would affect the performance of the engine ?

EdwardN

iTrader: (1)

The dome shape for the botton is generaly combustion chamber-it's shape is different from engine to engine, but volume is dictate by compression ratio which we desire to have on engine. In the mean time we need to save squish band with particular width and angle. So to follow all this requirements it comes to the dome on the botton, but again-shape is changing from desiner to desiner. So try to folow this and will understand how it is affecting engine performance.

Data

thanks for the reply, now i have more questions.

how would the shape and angle of the squish band affect the performance? As you said, the design of the squish band changes from engine to engine, but what is the general guide line the designer would follow ?

fastharry™

iTrader: (4)

and how does the shape of a TURBO plug help performance.....

EdwardN

iTrader: (1)

I don't understand if it is realy does!!!!!! I didn't see any difference. If you will able to make plug (or complete glow head like Rossi made 15 years ago) it will big benefit, but steel turbo plug still steel plug-for me no difference at all. May be just other way to charge extra $. Yuo know-profit will do ...............!!!!!!!!!!

fastharry™

iTrader: (4)

well,theres got to be some benefit(you would think).....but I'm curious as to the reason..shape,extra coil in the filament,takes up more cyl space for more compression....


I know they don't recommend them for off road use,as they are more fragile.....and harder to tune..

Hmmm..