High nitro content
09-06-2006 | 03:27 AM
#1
Thread Starter
High nitro content
Hallo pylon racers,
who can give me some good advice to use high nitro content up to 70 % in a speed engine.
What compression ration and what size of head ...... ????
I think the F1 racers from yesterday know.
Thank you for help.
best regards Michael
who can give me some good advice to use high nitro content up to 70 % in a speed engine.
What compression ration and what size of head ...... ????
I think the F1 racers from yesterday know.
Thank you for help.
best regards Michael
05-02-2007 | 07:32 AM
#3
Senior Member
RE: High nitro content
I think the marine guys know the most info as they go to 60% or more
What needs thinking about is nitro is more a liquid oxygen than fuel so at 70% the fuel is really 30% and the oxygen content is closer to 70%
What this means is if your motor was 100% nitro you would need 9 times more fuel for the same flight but would have approx 2 times more power
or for 4.5 times more fuel a smaller motor would give the same power as a bigger motor using no nitro
this simply means in a typical use where you take a high performance forty motor using no nito and which gives for simplicity example 1 bhp and then use 50% nitro you might expect to get 1.5bhp but your fuel use would be 4.5 times bigger and you would need a fuel tank 4.5 times larger
as nitro is not cheap compared to methonal often a figure of 25 times more in cost at 100% or 12.5% more for for 50% nitro fuel in real terms not counting oil element
In reality the figures will be usually less due to 20% oil content and other factors but expect running costs to be high at 50% some 6 times plus easy
As nitro puts so much liquid in the motor there is a cooling affect similar to methonal and compression ratios are usually less than non nitro motors
FAI fuel is 80% methonal and 20% castor and no nitro allowed
nitro injects extra oxygen into motor so it more a form of liquid oxygen instead to use a bigger motor or turbo charger
realy nitro is brain dead expensive way to get power and acceptable in a small cox where it cant get the oxegen from the air but very pricy way to get power for a 40 or 60 motor and cheaper to get a bigger motor like a 90 vr df swinging a cut down to 10 inch from a 12*8 and no nitro
Also worth noting is methonal is a fuel with a lot of oxegen also and as half the fuel is oxygen this explains why you need twice as much methonal as petrol benzine for the same functions except you tend to get 25% more power from the same motor using methonal as when using petrol benzine
As nitro is twice the price than USA for example $30 a usa gallon is norm there and in europe we can easly pay $100 a imperial gallon or 4.5 litre most clubs flying in Europe bans the stuff or restricts it to 5 or 10% for competition as it kills the sport DEAD when you use 30% nitro
now you know why the acro heli guys often previosly deep pockets go belly up and go back to sedate scale heli hovering around with petrol benzine models and convert to lipos at 100 cycles per pack
and there are big problems shipping the stuff with complex HAZMAT regulations
Ralf
What needs thinking about is nitro is more a liquid oxygen than fuel so at 70% the fuel is really 30% and the oxygen content is closer to 70%
What this means is if your motor was 100% nitro you would need 9 times more fuel for the same flight but would have approx 2 times more power
or for 4.5 times more fuel a smaller motor would give the same power as a bigger motor using no nitro
this simply means in a typical use where you take a high performance forty motor using no nito and which gives for simplicity example 1 bhp and then use 50% nitro you might expect to get 1.5bhp but your fuel use would be 4.5 times bigger and you would need a fuel tank 4.5 times larger
as nitro is not cheap compared to methonal often a figure of 25 times more in cost at 100% or 12.5% more for for 50% nitro fuel in real terms not counting oil element
In reality the figures will be usually less due to 20% oil content and other factors but expect running costs to be high at 50% some 6 times plus easy
As nitro puts so much liquid in the motor there is a cooling affect similar to methonal and compression ratios are usually less than non nitro motors
FAI fuel is 80% methonal and 20% castor and no nitro allowed
nitro injects extra oxygen into motor so it more a form of liquid oxygen instead to use a bigger motor or turbo charger
realy nitro is brain dead expensive way to get power and acceptable in a small cox where it cant get the oxegen from the air but very pricy way to get power for a 40 or 60 motor and cheaper to get a bigger motor like a 90 vr df swinging a cut down to 10 inch from a 12*8 and no nitro
Also worth noting is methonal is a fuel with a lot of oxegen also and as half the fuel is oxygen this explains why you need twice as much methonal as petrol benzine for the same functions except you tend to get 25% more power from the same motor using methonal as when using petrol benzine
As nitro is twice the price than USA for example $30 a usa gallon is norm there and in europe we can easly pay $100 a imperial gallon or 4.5 litre most clubs flying in Europe bans the stuff or restricts it to 5 or 10% for competition as it kills the sport DEAD when you use 30% nitro
now you know why the acro heli guys often previosly deep pockets go belly up and go back to sedate scale heli hovering around with petrol benzine models and convert to lipos at 100 cycles per pack
and there are big problems shipping the stuff with complex HAZMAT regulations
Ralf
