treehog
Mar 29, 2007, 11:19 AM
Posted in the JET forum as they know the OS 91 VR DF fan motor best I think :D
I have an idea to use OS 91 VR DF in prop mode if I cannot get the speed results I desire from the 133mm RAMTEC FAN
No I haven't jumped ship from electric as I get my 150mph fix from F5d but to get 200 with electric and bring it on holidays and need for power generator to recharge figure as temporary solution to exceed 200 mph this is the only fuel combo that exists at a OK price coupled with relative ease of getting fuel on holidays and cheaper than renting out generators or paying for rented cars grilled alternator :eek:
Also starting issues and tuning for big motors are not so bad as the tiny things which I gave up on
Also I will be be only looking for max speeds no mid range abilities or tick over needed
The LHS has one in stock and the credit card is getting warm again and the price is possible without the FAN and I put the deposit down
First issue is the plane will be a MAX SPEED fun craft delta with prop or RAM FAN and in the future the delta will receive a 6 kg pulsar :eek:
or if I win the lotto a a KERO turbine :D
The club issue means the pulsar in this year is a non starter and so next year will just do gurella flying in stickville with the pulsar and stay one jump ahead of the noise complainers and lucky with the constant depopulation of Europe's stickville there are more and more places to fly pulsar every year way outside the cities
The requirement are NO NITRO or if absolutely necessary 5% max as this could result in ~40 to 60% flight cost increases even with this low nitro level as i would be full tilt all the time so no fudging the numbers with slow up to reduce fuel burn
NITRO COSTS EXPLAINED
The logic is that as 100% nitro motor combo if it existed would be some 20 times more expensive and would need 9 times the fuel to replace methonal even though you get double the HP this leads to cost rule equation derived from fuel ratios
(The oxygen in fuel equation 2 units of air for nitro versus 12 air units for Methonal)
A sliding rule dictates for me as EU prices for fuel are double USA and example that 30% nitro would in effect cost me ~6 to ~9 times the price than methonal solutions suppling same HP
That means it would be best to reduce nitro to least possible and get a good tuned pipe and higher quality motors to get HP rather than throw nitro at the HP problem
So the suggestion of some 60 cheapo motor with 30% nitro would only be interesting for a occasion user and don't want to go down that road
and please non of this magnum 40 200MPH stuff with a dive following wind yadda yadda
as they have been known to leave with thier tails between thier legs when passed out by F5D types or gone home with thrown con rods from speed dives
I intend to use this craft as the main craft to get the highest speeds without to buy a turbine and not spend a bomb on fuel
The conclusion is a high quality high revving larger motor could supply the same power with no nitro than a highly stressed smaller motor on high nitro
Now I know why club member 60 acro heli guy figure LIPOs with 100 cycles are cheap as he was spending $2000 a year on 30% nitro fuel :eek:
Unless somebody knows my calculations on nitro are way of the beam I really don't want to go down that road except to say there is lots of info on nitro out there and you cant have a fuel with oxygen in it without to have a multiply affect kick in and the basic multiplier is some every 15% nitro will double the fuel cost s per fight
(ok increase power but at a very high price )
Any way I really don't like running costs of glow compared to predicable fixed cost of electric so I figure once I get the pulsar will probably sell of the motor or put it with my collection of extremely rarely used glows
The requirement in the speed
I wish to get would be as close to 200mph as possible in a dive better if its more like 250mph (I wish )and so as I flatten out for level flight expect speed to decay to some ~160mph hopefully 180mph plus (I wish ) :D
I cant find exact Data on the RAM to plug it into a motor calc to get idea of efflux velocity
I cant get info on OS 91 VR DF with no nitro and tuned pipe but suspect would be 18k
My basic formulas suggest a 10*10 carbon prop from aeronaut would supply the speeds at some sub 20k rpm
any experience on any props with or without nitro very useful to know
If the Ram can supply interesting speeds without to use Nitro on this very minimal airframe delta then I can hold back and purchase the FAN a few months later
I will do a separate thread on the delta itself basically a slightly scaled down internet plan version from high speed 85 newton pulsar delta with 10% wing foil or similar
The FAN option if the efflux speeds are suitable would be easier with the twin wing bladders and just sit where pulsar sits but failing that a smallest possible deep pitch prop solution
Any useful ideas shoot
Ralf
I have an idea to use OS 91 VR DF in prop mode if I cannot get the speed results I desire from the 133mm RAMTEC FAN
No I haven't jumped ship from electric as I get my 150mph fix from F5d but to get 200 with electric and bring it on holidays and need for power generator to recharge figure as temporary solution to exceed 200 mph this is the only fuel combo that exists at a OK price coupled with relative ease of getting fuel on holidays and cheaper than renting out generators or paying for rented cars grilled alternator :eek:
Also starting issues and tuning for big motors are not so bad as the tiny things which I gave up on
Also I will be be only looking for max speeds no mid range abilities or tick over needed
The LHS has one in stock and the credit card is getting warm again and the price is possible without the FAN and I put the deposit down
First issue is the plane will be a MAX SPEED fun craft delta with prop or RAM FAN and in the future the delta will receive a 6 kg pulsar :eek:
or if I win the lotto a a KERO turbine :D
The club issue means the pulsar in this year is a non starter and so next year will just do gurella flying in stickville with the pulsar and stay one jump ahead of the noise complainers and lucky with the constant depopulation of Europe's stickville there are more and more places to fly pulsar every year way outside the cities
The requirement are NO NITRO or if absolutely necessary 5% max as this could result in ~40 to 60% flight cost increases even with this low nitro level as i would be full tilt all the time so no fudging the numbers with slow up to reduce fuel burn
NITRO COSTS EXPLAINED
The logic is that as 100% nitro motor combo if it existed would be some 20 times more expensive and would need 9 times the fuel to replace methonal even though you get double the HP this leads to cost rule equation derived from fuel ratios
(The oxygen in fuel equation 2 units of air for nitro versus 12 air units for Methonal)
A sliding rule dictates for me as EU prices for fuel are double USA and example that 30% nitro would in effect cost me ~6 to ~9 times the price than methonal solutions suppling same HP
That means it would be best to reduce nitro to least possible and get a good tuned pipe and higher quality motors to get HP rather than throw nitro at the HP problem
So the suggestion of some 60 cheapo motor with 30% nitro would only be interesting for a occasion user and don't want to go down that road
and please non of this magnum 40 200MPH stuff with a dive following wind yadda yadda
as they have been known to leave with thier tails between thier legs when passed out by F5D types or gone home with thrown con rods from speed dives
I intend to use this craft as the main craft to get the highest speeds without to buy a turbine and not spend a bomb on fuel
The conclusion is a high quality high revving larger motor could supply the same power with no nitro than a highly stressed smaller motor on high nitro
Now I know why club member 60 acro heli guy figure LIPOs with 100 cycles are cheap as he was spending $2000 a year on 30% nitro fuel :eek:
Unless somebody knows my calculations on nitro are way of the beam I really don't want to go down that road except to say there is lots of info on nitro out there and you cant have a fuel with oxygen in it without to have a multiply affect kick in and the basic multiplier is some every 15% nitro will double the fuel cost s per fight
(ok increase power but at a very high price )
Any way I really don't like running costs of glow compared to predicable fixed cost of electric so I figure once I get the pulsar will probably sell of the motor or put it with my collection of extremely rarely used glows
The requirement in the speed
I wish to get would be as close to 200mph as possible in a dive better if its more like 250mph (I wish )and so as I flatten out for level flight expect speed to decay to some ~160mph hopefully 180mph plus (I wish ) :D
I cant find exact Data on the RAM to plug it into a motor calc to get idea of efflux velocity
I cant get info on OS 91 VR DF with no nitro and tuned pipe but suspect would be 18k
My basic formulas suggest a 10*10 carbon prop from aeronaut would supply the speeds at some sub 20k rpm
any experience on any props with or without nitro very useful to know
If the Ram can supply interesting speeds without to use Nitro on this very minimal airframe delta then I can hold back and purchase the FAN a few months later
I will do a separate thread on the delta itself basically a slightly scaled down internet plan version from high speed 85 newton pulsar delta with 10% wing foil or similar
The FAN option if the efflux speeds are suitable would be easier with the twin wing bladders and just sit where pulsar sits but failing that a smallest possible deep pitch prop solution
Any useful ideas shoot
Ralf