ghost123uk

I normally fly control line stunt / combat etc.

I am a reasonable R/C flyer, but no expert.

For fun I fly a park flyer with a std 380 brushed motor.
It came with a broad bladed plastic prop that has served me well until last weekend when I broke it.

Question, is there any disadvantage to using a prop as might be found on one of my control line models such as APC / Kavan etc ?

RickAvery

Most brushed motor park flyers use a gear box to allow use of a larger prop at a lower RPM. Large bladed slow flyer props aren’t made for high RPM applications, and are constructed usually with smaller hubs and lighter overall weight. Likewise, APCs ‘E’ prop series are designed for higher RPM applications. They have a larger hub and beefier overall construction and weight. This is easily seen when comparing say, an APC 9X6 slo-fly prop and an APC 9X6e prop. A couple of things may happen, Your park flyer may fly with an 'E' prop but may suffer some performance due to the higher weight of the beefier prop making the motor work harder or it may not fly at all if you use a gasser prop that is to thin and wouldn’t spin fast enough to create enough thrust. Try it and see what happens. I’d get another wide bladed slow flier prop and probably pick up 2 while I was at it. Good luck
Rick

russzero

hi .. sorry i think i may have asked a simular thing later on in the posting .. but can i add something to this thread. The recomended prop for a 300wtt brushless ive bought .. supposedly is 10x6 or 11x6. With a 10x6 it rips .. but trips the esc due to hi current draw. I fitted a 8x4 ( only other near size prop i have ) & it does work (2 good 7min flights) but would a "electric type" prop make any difference. The motor is direct drive .. no gearbox. Its a kavan prop .. pretty bendy .. we used them a lot at our old power field due to the rough terrain .. the kavan do take the knocks. Also they will unwind a bit due to the flex .. so i was quite a fan. I was told a good wood prop was best .. but u could end up fitting a new one every time u flew at our old field..!!
thanks ... russ

ghost123uk

I have moved ahead slightly since I wrote the O.P.

I now have a 300 Watt - 1100 RPM/V direct drive motor with a 12C 3P 1800mAh pack and 30A esc.

As I will be using this set-up in a light 39" span "herr Lil Extra" ( ready and waiting for it's maiden flight ) I have fitted it with a 8x6 "Master Airscrew" I.C. prop.

To my way of thinking, this should turn at around 14.000 RPM so equivilent to a similiar I.C. motor revs, but will not stretch the current rating of the pack or esc as the motor manufacturers say you can go up to an 11x6 on this motor ( = 30 Amps )

So I am hoping it will work fine, run cool and have a better run time.

Not sure what if any dissadvantages I might experience in this I.C. prop set-up ?

I mean what is the difference in an "E" prop and an I.C. prop is if they are both turning at the same RPM ?

russzero

yeah i dont quite see the difference .. its the same in other electronics .. like the blatant use of "digital" on things like headphones. i was 20yrs in the electronic trade & can see thru it. capacitors are capacitors & revs is revs .. but i do understand the ic engine is not the same as a dc motor so there are differences. ive been told several reasons for using a APC or electric prop .. mainly weight. i did dispute the electric v wood propellor as wood was suppost to be very good & light .. but was to no avail.
i think the model shop keeper likes to stick £££expensive items in your hand while others are waiting in the queue .. just to watch u sweat a little more .. while others look on. ha.
anyhow .. sounds like the outrunner uve got is simular to my one. its a pretty amazing device .. the only thing to be concerned about i would say is the way the hole is drilled out when using a IC prop. the balance is all important as u know anyway .. but those drive shafts on DC motors are massive in comparison. its gotta be a way to make u buy the "correct" prop .. like car manufactures do with the type of bolts used on parts & special spanners required to remove them etc. anyhow .. cant wait for lipo batts to come down in price .. if they ever do .. then ittl be great ..

ghost123uk

Hey Russ
You and me have alot in common
I was in the electronics trade for about 20 years too !! ( ran my own lil business )
Also hated all that "digital ready" sh1t applied to components !!
Oh, and you are in the UK too.

Re prop balance - yep more important on these motors and some of the I.C. ones are really bad ( Taipan in particular )

I just got busy at work so better get doing what the boss needs me to do !!!

Talk later