Head speed Question.

[spykez]

Planning to swing stock 520's. Thanks for the answers all!!!

Just to clear this up - will I have issues with the stock kit ESC with a 16T if I v-bar govern it down to 2200-2400?

Off on another tangent, I know sims aren't like the real thing but I've no problems with noob circuit flying and simple inverted forward flight stuff using the the RF6 Gaui X5 at 110% physics and IU 2400 and 2600 headspeed on the sim.

How close is this model to the real thing? If it's pretty close I might as well aim for 2400-2600. I don't know....

[Harrow]

Originally Posted by spykez

How close is this model to the real thing? If it's pretty close I might as well aim for 2400-2600. I don't know....

I'd be aiming for 15T and 2300-2400. That's what a lot of guys in here are doing, and it works really well. Don't think there's much need to go above 2400 unless you really want to bounce it around hard. You'll get longer flight times, and the 15T will give you better motor efficiency. At 2400, you still have plenty of power and pop.

[spykez]

Sounds like 15T is what I'll need. Thanks. It'll come with a 16T I guess so I could always go up a tooth. Maybe I should just get a number of pinions 14-16 and give 'em all a try.

Are they a right pain to switch?

[kkkklee]

Depending which esc you used . changing the pinion is easy . 10-15 min all done . Set up the esc is really depending on which esc you have .

[spykez]

Originally Posted by kkkklee

Depending which esc you used . changing the pinion is easy . 10-15 min all done . Set up the esc is really depending on which esc you have .

Stock ESC from kit. Think it's a 16T stock pinion as well. Will probably v-bar govern the ESC. Thus I was wondering which of the 3 pinions to think of getting 14, 15 or stock 16.

Sounds like I may want a 15 or maybe 16 will do to.

[kkkklee]

I don't have vbar . But one of my buddy he use vbar governor and yge esc use 15t pinion to spin the 520 mm blade had a very good result . For me , i will not use 16t pinion because it will put too much loading on the motor and draw too much current from the battery .Unless you use 500mm blade . i know Xera 4020 1000kv motor can accept 14t pinion with ton of power but not the stock motor 910kv , it will run too slow .

[farn]

I use a YGE 120 with gov store with a 16t pinion with 520 EDGE blades and 2480 headspeed and it works great. I measure amps, voltage and headspeed with the IISI System and it works great. Before I had a 15t with 2350 rpm and the amp draw was about the same than with the 16t.

[helidude71]

Originally Posted by kkkklee

Yes I run with normal gov set on yge100
15t run on 520 blade will give esc more head room for gov and still can run good head speed. You need 16 t if you run on 500 mm blade.

Really? I'm amazed by that.
But it's good news!
Better not loose torque by gearing up.

So 2400 rpm with 15T on YGE governor is no problem?
How high is your throttle curve?
If I use MrMel calculator my guess it's very close to 90%.
Is it possible for the YGE gov. to use 90% TC?

[helidude71]

Originally Posted by farn

I use a YGE 120 with gov store with a 16t pinion with 520 EDGE blades and 2480 headspeed and it works great. I measure amps, voltage and headspeed with the IISI System and it works great. Before I had a 15t with 2350 rpm and the amp draw was about the same than with the 16t.

OK, could you run 2400 gov. with the 15T?

[tmafra]

If you use Mr. Mels calculator with a 15t pinion you shouldnt go any higher than 2350 rpm governed (vbar)

For 2400 + you should use 16t pinion

Im running 2400 with 15t pinion and vbar governor and i think its fine this way but its on the limit of the - performance on the graph you get from the calc

[spykez]

Thanks guys for all your feedback, I think I'll drop a tooth and see how my v-bar likes it (when I get it all together). Can't wait. Can always go back to a 16 I find that's not enough. I doubt that will be the case for a while to come with my level of flying anyways.

[Harrow]

Guys, don't forget the headspeed calculator is trying to maintain headroom at the end of the flight with reduced battery voltage. So, you'll be fine for most of the flight, and it will probably only become border line for the last 30 seconds. Since that part of your flight should consist of a big auto from 100 feet up, I'm sure it won't bother you.

[spykez]

Originally Posted by Harrow

....Since that part of your flight should consist of a big auto from 100 feet up, I'm sure it won't bother you.

Sure... 100 foot auto, 100 metre autos.. no worries. Doesn't bother me at all. Just hitting the ground does

Seriously, when I get my kit together, I'll just do it nice and slow, take it up for 4 mins and take it down and check the lipos, that sort of thing.

Any of you guys here use telemetry, as an aside? Wonder if it's worthwhile.

[farn]

Any of you guys here use telemetry, as an aside? Wonder if it's worthwhile.

Yes I use IISI System. Link: http://www.IISI-rc.com
This is a wonderful system, very accurate.

[farn]

OK, could you run 2400 gov. with the 15T?

No not with 85 or 86% throttle. With the gov store with 85% throttle I had 2300.

[kkkklee]

Gov store usually run slow on head speed . I get maybe 2400rpm on 92% straight curve .i switched to normal gov , head speed is 2450rpm at 85% straight curve . I like normal gov , easy on the motor .

[helidude71]

Great! I guess I don't need gov. store mode because I got 3 new GensAce packs with the bird.
All with the same charge cycles on them.

I'm going to try the 15T pinion with normal gov. and see how it goes.
I can always change to a 16T if needed.

[helidude71]

Originally Posted by Harrow

... Since that part of your flight should consist of a big auto from 100 feet up, I'm sure it won't bother you.

Priceless

[spykez]

Originally Posted by tmafra

If you use Mr. Mels calculator with a 15t pinion you shouldnt go any higher than 2350 rpm governed (vbar)

For 2400 + you should use 16t pinion

Im running 2400 with 15t pinion and vbar governor and i think its fine this way but its on the limit of the - performance on the graph you get from the calc

My kit has arrived happy happy joy joy...

Because I could not decide, I got the 16Tand 15T pinions... still trying to make up my mind.

If the RF6 sim is anything to go by I'll probably want 2400 rpm, governed. That model I can fly simply, reasonably well. I know that that means little in real life unless some of you really feel the model is reasonably accurate. Still, I need to make a guess, so I'm guessing 2200-2400 is what I'll want.

My 2 options for a governor in order of preference is the v-bar (getting sensor) or the stock ESC. Either case for now, I'll run a stock ESC. If that dies, I'll get a YGE probably because of some familiarity on my msh more than anything else.

My rough calculations mean that at 22,2v :

with the 16T I need 90% throttle for 2400, and about 82% for 2200.
For a 15T, 95% Throttle for 2400, 87% for 2200.

This is just theorycraft of course. Those are my 2 intended IU speeds to start with.

David at GlobalRC was suggesting the lower tooth count for better efficiency and more torque and at least initially shooting for 2200, but I am wondering will the v-bar have trouble with a 15T governing 2400. Is that good enough?

An alternative... If I shoot for 2300 15T, I estimate I'll need 90% throttle.

What are the relative advantages and disadvantages of 15T vs 16T given that desired RPM range 2200-2400?

Also note my most likely choice of governor - the v-bar.

My still noob understanding of the governor is that if I go with a 15T, and reallly push it hard, it will probably bog a bit. especially later in the flight. There will be more torque applicable though, due to the gearing.

However with a 16T, the motor will exert possibly less torque, but it would seem that the ESC would have more room to move to compensate. I realise that the lower the throttle signal to the ESC the harder it'll have to work - but I don't understand the nitty gritty of it all.

Anyone have any advances on the above? Or can point me to a great resource?

Or am I just over thinking this, and should just go eeny meeny miny mo... and pick one and just fly?

Thanks all!

[helidude71]

Well, I can't decide myself, 15T or 16T.

I do know I like 2400rpm, tached mine when flying a normal TC.
It feels snappy and quick with 12.5* collective pitch at 2400.

My YGE is on it's way, because the 15T is already on I'm going to try that first.
If it doesn't work I get a 16T.

So much for my calculations.