Originally Posted by fandjet

Hello! And who knows what timing and frequency of the motor
RC Dr Mad Thrust 3000kv 1300w 70mm EDF Inrunner Motor 4s version (29mm)?

What current draw do you have on that set up?
Thx.

I'll apologise straight out of the box, I've started to read the thread, but 500 pages will take some time, and my question no doubt has been asked many many times

So here it is, I'm newish to edf, I fly a Dynam ME262 foamie, with stock twin 70mm edf, 2826 3200kv outrunners, using grapheme 6000mah 4 cells, two 60a esc's. Dynam make nice airframes, but I know the running gear is more than likely budget end, its a lot cheaper than the freerwing comparison 262

Ive read that thread, equally as big, front to back, as its a known fact that this bird is somewhat under powered (slightly), and my bird has gained weight, with a custome paint job, upgraded retracts, a sound unit, and the huge big battery.

Feedback is CS 10 blade fans are much better, however, motor info is somewhat limited. I really want to stay with the 4 cells, as these batts, a few months old now, cost me a fortune!

Flight speed is fine, its not a racer, but over scale speed, with 3 1/2 mins flying (would be nice to be more), but It lacks thrust. After the first minute this battery should not be struggling, and take off speed, on a cut grass flying site is marginal.

I'm unsure which direction to turn with this, I love the plane, but its a lot of effort for only 3 and a bit minutes of 3/4 throttle and a worry of stalling on take off.

Any suggestions, without paying a big load of bucks, would be appreciated, here is a short video just to give an ideas what I have

ME262 with Mrrcsoundunit Halsall 30082018 (5 min 33 sec)

Paul

If you stay with 4S Flight times will only get shorter if you go with higher blade count fans. You should switch to 6S. Get a couple FMS 70mm 12 blade setups or FW 12 blade setups for 6S. Unfortunately higher amp ESCs will also drive the price up.
Maybe you can find a wrecked FW 262 which someone is willing to part with (for parts)?

Thanks for info 4stripes,

Is there an easy explanation as to why the increased blade count causes more amp draw, I was thinking the blades are smaller surface area, so easier to turn? Obviously wrong!

Looks like its increased cells, but Im so loathed to do this as I have no other plane for the big graphene 4 cells

If you have a pair then you are ready for an 8S jet like the FW Phantom. Just keep them at storage voltage and they will be good for a while.
The other option is just enjoy your jet the way it is. Maybe take a stab at dynamically balancing the edf’s. Once properly balanced the sound will improve dramatically.
You could also try changing to the higher blade count rotor (Changesun 10 blade) and carefully check the draw using a wattmeter. There is a chance it will be able to work up around the 60amp range. It will certainly give you more power but the motors may not like the extra load. Using a wattmeter and an IR thermometer you can monitor the motor and ESC temps to see if the system is happy. As long as the motors don’t have temperatures climbing much higher than about 170F then I would say they are good. Looking at other 70mm fans advertised to run 4S and higher blade counts the motors are around 3000kv to 3300kv so it just may work. Again the flight times will not get better but you will have the power. Is there any way you could remove the sound system and fit 2 of your packs and still balance the CG?

Great idea just trying the extra blades. I could remove the sound system but the second pack would just be too heavy and a big shift with cog.
I think I’ll try the fans as they are quite cheap see how that goes.
Your not the first to say just enjoy it as is! It’s just a bit marginal on rotation speed.
I expected an improvement with the esc timing change but that was a curve ball indeed so they might as well go back to low timing
Paul

I have successfully swapped to 10 blade rotors on the old foamy Habu inrunners. It required a larger ESC and for insurance I added a heat sink to the motors.
It is certainly worth a try. I suspect your weak link to be the ESCs if they are not in the ducts for maximum cooling.

Cs 10 blades ordered now! Due in a few weeks then testing can begin. Are we the only two on this thread?��

There was a time it was hard to buy decent complete edf’s so there was more experimenting done with fans. Today most just buy something off the shelf (or internet) and don’t build their own setups. I personally enjoy building them up and doing the dynamic balancing. It is quite satisfying to get a fan that runs smooth and pulls the power you need.

Originally Posted by pmdevlin

I'll apologise straight out of the box, I've started to read the thread, but 500 pages will take some time, and my question no doubt has been asked many many times

So here it is, I'm newish to edf, I fly a Dynam ME262 foamie, with stock twin 70mm edf, 2826 3200kv outrunners, using grapheme 6000mah 4 cells, two 60a esc's. Dynam make nice airframes, but I know the running gear is more than likely budget end, its a lot cheaper than the freerwing comparison 262

Ive read that thread, equally as big, front to back, as its a known fact that this bird is somewhat under powered (slightly), and my bird has gained weight, with a custome paint job, upgraded retracts, a sound unit, and the huge big battery.

Feedback is CS 10 blade fans are much better, however, motor info is somewhat limited. I really want to stay with the 4 cells, as these batts, a few months old now, cost me a fortune!

Flight speed is fine, its not a racer, but over scale speed, with 3 1/2 mins flying (would be nice to be more), but It lacks thrust. After the first minute this battery should not be struggling, and take off speed, on a cut grass flying site is marginal.

I'm unsure which direction to turn with this, I love the plane, but its a lot of effort for only 3 and a bit minutes of 3/4 throttle and a worry of stalling on take off.

Any suggestions, without paying a big load of bucks, would be appreciated, here is a short video just to give an ideas what I have


Paul

Hi.

Don`t have any experience with this plane, but I took a look at the Dynam thread, TheDon did have a good ide with thrust tube in this post:https://www.rcgroups.com/forums/show...&postcount=657

Maybe try some thrust tubes is the easy way for better performance?

//Magnus

I have thrust tubes in mine but it made immeasurable difference. (in the Dynam Me-262)
It is bound to help... it has to technically... but how much? Seemingly not much.....

Yep a thrust tube with the right size exit would make quite a difference. You might be losing thrust from the set up you have. Work on the tubes and on balancing the fans, it would make a difference.

Originally Posted by 4stripes

If you stay with 4S Flight times will only get shorter if you go with higher blade count fans. You should switch to 6S. Get a couple FMS 70mm 12 blade setups or FW 12 blade setups for 6S. Unfortunately higher amp ESCs will also drive the price up.
Maybe you can find a wrecked FW 262 which someone is willing to part with (for parts)?

I recently bought changesun 70mm 12 blade units for a plane. If I grab some 10 blade units, about how much more flight time am I going to get than if I stick with the 12 blade units? A minute? 30 seconds? I just want a rough idea. Thanks.

10 blade fan pulls about 7% less current than the 12 blade. This may not give 7% better flight times as it depends mostly on pilot throttle management.
The main benefit is less stress on the motor, ESC and battery.

Would the exit on the tubes not be whatever diameter the nacelle is? So it can’t be bigger so is smaller better. Is the advantage just a smooth surface?