Mini Q

[NCRealEstateGuy]

Is there not a way to get a motor in there that would sit behind the mount so, I could get a spinner on the shaft and have it line up with the cowling. Yes, I want to use a folding prop. I really dont want to have the motor sticking out like that.

 

[Konrad]

Why can't you just set the firewall aft 20mm? Select heavier (stronger batteries) to help with balance, and have fun.
I think Aeronaut’s has folding prop yokes (center piece) that has a straight center bore. And if your model still isn't fast enough you can get twisted yokes that add more pitch to the prop.

aero-naut Modellbau GmbH & Co. KG - Prop centre pieces

www.aero-naut.de

 

[NCRealEstateGuy]

I thought about pushing it back like that. But, I suppose I should just wait until it arrives, and I can put eyes on it and measure the inner diameter of the nose. Not even sure I could push that motor back far enough without it rubbing the sides.
Are there no small inrunners that plug from the rear that would fit?
Thanks for the link to the yoke arms.

 

[Konrad]

Yes, there are Inrunners take a look at Neu motors.

Not sure what issues you are seeing with out-runner. They should fit and there are plenty of firewall (nose ring mounting options).
I’d think the Hacker A20 series should work well. And if going with the longer can (rotor) you should be able to put a lot of power in the nose.
https://hackermotorusa.com/shop/hacker-brushless-motors/outrunners/a20-12-l-10-pole-evo/
https://neumotors.cartloom.com/storefront/category/direct-drive-motors

P.S.
It is looking like the 22XX motor has a 22mm stator and 28mm can.
Is this in fact the case? If this is so there should be a host of small EDF outrunners available.

This should get your heart beat up there!

Mega ACn 16/7/5

More compact and lighter than a speed 400 can, this motor is an excellent choice for speed 400 size pylon racers. It also is a good choice for 60mm ducted fans given its 3450KV wind. FYI, Mega also sells a Microgear box for this motor that allows it to spin a 10" prop.The Mega ACn 16/7/5 is a 3...

alofthobbies.com

 

[Wayne]

There are a ton of motor options for this plane that will allow for a folding prop and spinner. You could be an outrunner or an inrunner. But if you go after a 2200kv I don't think you will be able to use a folding prop as the RPMs will be too high for the folder. This is what I was trying to explain.

 

[NCRealEstateGuy]

You are right... And I really want to have a folding prop. So, a motor up to 600 watts? Maybe 3 cell?
I also ordered the EMAx 3352 servos.
Konrad, that Mega motor looks real nice. But I'll start out with something a bit cheaper. Maybe like you said... some little edf motor.

 

[Glenn Beer]

Yes. 22xx size motors will fit if you move the firewall back. If you choose a spinner that has a 5 mm collet, it will tighten onto the quad motor shaft.

 

[NCRealEstateGuy]

Thanks Glenn. I was not sure if a prop collet would work. I suppose those shafts on the 22xx's have a threaded hole into the shaft to secure the spinner?
I may just go with a folding prop, which would limit my speed, but I have decided that I want to glide around more than having crazy speed.
Another noob question... Can this plane be thrown around and flown somewhat like the Alula? On very small hills and "Urban" slopes? Or is it too heavy? Can it be discus launched and then caught when landing?

 

[Konrad]

Not sure that there is enough contact area on the 5mm threaded shaft for a collet. The tips of the thread may be an issue. Have you had good luck doing this, and if so at what power levels?

 

[Wayne]

Sean did that here at the shop. He is pulling 500 watts on a 7x4 folding prop using one of the DYS fire motors. He is at the RPM limits for that blade set, he uses it for his Geronimo glider:

Horejsi Geronimo II

Those of you who fly DLG's may be intrigued by this plane. In short what we have here is a 500 to 600 gram, 2 meter electric with separate flaps and ailerons. The construction is very similar to, but slightly more robust than a DLG. The matt surface finis

alofthobbies.com

It has worked well.

 

[Windy Miller]

I’ve an electric setup with the motor mount back into the fuse, all works fine but I’m not getting the speed I want and the folding prop isn’t folding but free spinning which feels feels like an air brake when I want it to zip along... tried all sorts to get the brake to work on the ESC including contacting the manufacturer to no avail so far. Didn’t have to add any weight though, running a 2S setup. Interesting to read that folding props are not a good idea - I’m going to try some different combinations to see if I can get a better result. Inverted isn’t great at the moment but I don’t thing I’ve got it to the perfect setup yet... I’d like to keep the folding prop for 2 reasons - I like a bit of speedy silent gliding and it doesn’t dig in on landing...
Talking of landing and to answer the DLG catch landing question - I don’t fancy catching mine - comes in far too fast - its easy to land but wouldn’t want to try to catch it (OK I could be a better pilot of course but do catch and go with my DLG) (sometimes)

 

[Konrad]

I’m a bit lost, not unusual for me.

Sean did what, used a 5mm collet against the threaded shaft and has been able to drive 500 watts through this junction?

WOW, 500 watts in that light airframe! I driving around 600 watts in a 1.950kg 3.2 meter glider and have way too much power (read vertical climb).

Yes, a freewheeling prop is a very effective airbrake. Folding props are used to try to clean up the airframe to extend the efficiency of the glide (cut down on drag). It is not directly a speed thing.

I think Wayne was saying that there are few if any commercially available folding props in this size range to can absorb 600 watts of power.

It is quite easy (but take a lot of steps) to make your own set of blades that use continuous fibers that go around the pivot point. Harry Higley has details in Master Builder book. So the question is how fast do you want to go and how much work are you willing to put into the project?

Sorry about the Amazon link

Amazon.com

All the best,
Konrad

P.S.
What brand and model of ESC are you working with? Many brands have brakes that are weak or don't work!

 

[NCRealEstateGuy]

WIndy Miller, what type of electric motor you running in yours? I'm trying to find a 28mm inrunner or outrunner for mine. Need to be lower kv. I will be running a folding prop. I want the motor to sit behind the motor mount. I realistically would want about 450 watts. Any ideas on motors?
I received my yellow / Black model a few days ago... packaged nicely and it looks really nice.

 

[Konrad]

This "class" of motor should fit the bill. You will or should derate the motor when moving from an EDF to prop. This has to do with the ability to carry away heat.

E-flite BL15 Ducted Fan Motor, 3600Kv | Horizon Hobby

The BL15 Ducted Fan Motor, 3600Kv by E-flite is a quality built remote controlled airplane accessory. See all our RC product options online at Horizon Hobby!

www.horizonhobby.com

 

[NCRealEstateGuy]

But won't that high of a kv produce too much to use with a folding prop? I came across that series of motors, and they are all high kv motors. I need a motor that will produce about 450 grams of thrust, maybe a little less, that when wide open, does not surpass my prop.
My plane weighs in at 197grams.
I can build it to weigh about 475.

 

[Konrad]

"Class" of motor (weight and size). Yes, you might want a much lower Kv motor like a 1600 to 2000Kv. Not sure what you're looking for from 450 watts. That should be well with in the safe power and RPM range of most 6 to 7 inch folding props.

You want close to 1 watt per gram of power! That's about 450 watts per pound! What are you trying to do? Mimic a 30-06 bullet! If this is to be a speed ship, don't pretend it is a glider, and just do away with the folding prop. Most of my fixed props just kick out of the way on landing. I land (skip) on asphalt. Yes, I bring a 1/2 dozen props with me, just in case. Such is the price of speed!

 

[Windy Miller]

Sorry for the late reply - here's my setup:
Brushless Motor2212/5T 2700KV SMC-MTR317; Folding Carbon Propeller Set 7 x 4 Electric Flight; Overlander XP2 20A Brushless ESC
Overall weight depends on the battery - I'm using 2 at the moment - both 2S - a 1,000mAh and a 1,600mAh overall 388g or 439g which I think is OK from everyones comments.
I do have a 3S 900mAh which I'll try at some point.

As I've said I can't get the brake to work on the ESC.

I'm going to have to test some other props at some point (when the weather warms up a bit)...

 

[Wayne]

@Windy Miller Isn't that pretty darn slow on 2S? I have a similar motor on that plane I linked to earlier, but running 3S and a smaller prop with more pitch. That was about 85mph. It is actually setup for 4S battery, at that point it comes alive with your 2700 kv. But you can't spin a folding prop that fast, they have RPM limits for safety. You would probably be OK on 3S.

The limit on the folding props is not the wattage, but the RPMs.

I'd have to run some numbers on that eflite motor Konrad linked above, but it might actually be an OK choice for 3S battery. Price is not horrible and it has a 4mm shaft. Not too bad.

 

[NCRealEstateGuy]

I found an old, brand new Turnigy 2836 1100kv that I will try in my nose. With a 3 cell, probably a 1350 pak. I just ordered a couple of spinners and a 9x6 folding prop.

 

[Wayne]

Will that fit in the nose?

Should do fine, but it will be a moderate speed plane with that setup. You could always drop in a 4S and a little different prop later if you feel the need for more speed. But climbing up, then folding the prop and speeding back down is always fun.