Mini Q

[NCRealEstateGuy]

Yup... not going for all out speed now. I wanted the folding prop, so this will be just about right. Its 27.8mm in diameter and the inside diameter of the plane is about 32mm. I am a little concerned about cooling air being able to get in and out. I will probably cut some exit holes in the rear somewhere. Trying a 9x6 folder first. And I will be installing a 30 amp esc in case I want to put a little 4 cell battery in there as Wayne suggests. I see it climbing up pretty quickly, and then cutting off motor and soaring around until its time again. Take it out on those windier days. Ill have to enlarge the motor mount since I will be pushing my motor back... the fuse diameter gets slightly larger as you go back.
Windy Miller, like Wayne says, hook a 3 cell to your 22 motor, reprop it and see what you think. At only 439 grams with that two cell, 1600mah battery, you have room to spare, weight wise.

 

[Greg Beshouri]

Andy, Gerard and I maidened ours at the SLoT on Saturday. The general consensus was WOW! Wow the numbers say this aircrfat is heavy "it flies like a much bigger plane" as our mentor Bob Miller would say!

I started with the CG at ~24(?). That was fun but it tended to tuck on a dive. So I moved forward to 22 mm from leading edge for more relaxed flight. At 379 g or 13.4 oz the elevator is +/-4mm, Elevon trim ranges from 2-3.5mm up depending on flight conditions. Aileron is +/-10mm though the roll is a bit weird. Inverted is easy.

All pictures by Gerard!

 

[Windy Miller]

Thanks for the comments - I'll do some trial and error and hopefully improve things, it needs to speed up a lot but I don't want to add a lot of weight if I can help it.

NCRealEstateGuy - I'd be interested how you get on with the folding prop as that's the way I'd like to go, but I will try a smaller prop with more pitch as Wayne suggests.

I'll have to have a go with a 4S at some point but will need another ESC.

I made a larger motor mount and installed it further back, not difficult but I too thought I needed exit holes - just didn't want to cut into the fuse !! I'm thinking the holes need to be quite big don't they? NCRealEstateGuy let me know how you get on.

 

[Konrad]

Motor cooling for climb and dive do NOT need large holes. In the 5 to 10 second climb, motor mass has more to do with keeping the motor from over heating. During the long glide a little air flow can carry away a lot of heat. Just make sure there is flow over the motor. (Remember that most out runners will get a drawing fan effect from the rotor end cap).

Most well set up brushless motors are running about 80% effecent, it is the heat in the batterys that is the real issue. Luckily batteries have more mass than most motors.

All the best,
Konrad

 

[Wayne]

Could always put the cooling hole on the canopy. It is not structural, but not sure it would not see a vacuum there.

All honesty I would suggest giving it a flight without any cooling holes. Just keep things on the gentle side for the first flight, and when you land check and see if there is a heat concern or not. The setups mentioned here seem like they would not be much of a heat concern. If you know you are on a edge of the motor limits, then yes, you will need some cooling. For example when pulling 500 watts from a multi rotor motor.

 

[NCRealEstateGuy]

If I was using a 22x size motor, I would probably not worry about cooling air, as there is a lot of space around the can and fuse. With my 28xx motor, there is only about 2mm worth of open space between fuse and can. kind of tight. I'll fly it first, then see if it needs more cooling.
Windy Miller, where do you fly yours?... CG wise? What type of flying do you find yourself doing with yours?

 

[Wayne]

Just looking at that 3600 kv BL15 from Eflite - Not a bad little motor on the specs. Looks like you can get about 90 mph on the flat with a 4.5x4.1 prop pulling around 50 amps. The motor is rated to about 55 amps for brief bursts. I was hoping for a little more speed, but not bad. APC offers a 4.7x4.2 blade, that kicks it up to 57 amps and 93 mph.

 

[NCRealEstateGuy]

My 34mm spinner seems to fit well and this type will allow for some cooling air. My replacement servos should be here today, so I can install them soon. Once installed, I will put everything in place to see if my CG is even close to where it should be. Should come in around 485grams with a 3 cell 1350mahr; 9x6 prop.

 

[Fotoflyboy]

Today at 7:51 AM
Hey guys and gals,

I’ve been following to do my build. I’ve flown slope acro since the 70’s, took 20 years off and things have certainly changed! I’ve waited to post until I have some good data to share so here goes.

First, I changed the linkage to a Z bend with metal clevis, way cleaner and 6g lighter. I started off with cheap dream flite servos but they have some slop. Can anyone recommend a better servo?

I ditched the servo trays to save on weight. I’m playing with various tacking methods. I’m gonna try wrapping the servo in tape and tacking the corners with 5 min. Epoxy.

My most recent upgrade is adding a carbon fiber spar instead of a bamboo skewer. Way stiffer and probably better for all of us but especially flying power. I stole the spar from my Ahi (no big loss).

My maiden was a trial by fire. 20+ knots at Torrey Pines with all the crew watching (and expecting me to crash!). She was a little nose heavy (good for that day) and she flew like she was on rails. I was rippin‘ it up with the big dogs.

That said, the CG was my biggest issue, mostly because of the question of where to measure. With the radius at the wing root and forward sweep of the wing, I decided to arbitrarily measure the CG at the inboard margin of the servo bay. At that point, 25 mm is very tail heavy. Hopefully I can do some more testing today. My gut tells me it’s 20-22 mm, which would be close to 25 at the wing root.

That’s all for now. Fly it like you stole it!

P.S. I’m at 11 oz. all in

 

[mopetista]

My 34mm spinner seems to fit well and this type will allow for some cooling air. My replacement servos should be here today, so I can install them soon. Once installed, I will put everything in place to see if my CG is even close to where it should be. Should come in around 485grams with a 3 cell 1350mahr; 9x6 prop.

looking forward to your report - thinking that you would have more fun with more pitch-speed with this small, light plane using an 8x7 (or, better, 4s with a 7x6 - both folder sizes available from Aeronaut, e.g.)

 

[NCRealEstateGuy]

Mopetista, I thought about lowering the diameter and increasing pitch also. I was thinking the 7x6 with a 4 cell too.
FotoFlyboy... how did you get the spar glued in. How long is it?

 

[NCRealEstateGuy]

Can someone tell me where they take the measurement for the CG... I realize it is about 22mm, but from exactly where are you all taking this measurement? After the wing root radius?

 

[gp49]

I projected the 'straight' line of the leading edge into the fuse and measured from there (bypassing the radius). Our Q flew very well right-a-way.... Don't forget the reflex up, or be ready for a nose dive....

 

[NCRealEstateGuy]

Thank you much gp49. Yes, 2.5mm of reflex so I read here. That's a lot, but if that is what works, well then, ok.
I installed the servos and the motor mount and motor today. I need to run to the local hobby shop and pick up some metal control rods for the servos. I will be using a Z bend on the servo arm and the stock metal clasp at the control surface.

 

[NCRealEstateGuy]

Windy Miller, did you incorporate some down and right thrust with your motor?

 

[NCRealEstateGuy]

I installed the control horns today and the connecting rods. I used 2-56 size rod but I had to use some different clasps, as the stock ones have some odd size threads that do not accept the 2-56 threads.
I temporarily installed all of the components needed and looks like it will be easy to hit the CG. AUW with battery is 483grams.

 

[Wayne]

The Sullivan clevises are better anyhow. The stock ones are 2mm threads.

Looks good!

 

[Konrad]

Odd size? Metric is the global standard. It is the imperial measument system that is now odd. BTW: I like the M.P. Jet hardware and their clevis with removable pin. I put less stress on things as I try to seperated the horn from the clevis by pulling the pin with the M.P. Jett stuff. I hope Wayne is able to bring in this M.P. Jet hardware.

All the best,
Konrad

 

[NCRealEstateGuy]

I consider it an odd size since NONE of my benchstock rods worked with the clevices. I consider it an odd size if both local hobby shops had nothing to fit them. I consider it an odd size if none of my dozens of spare clevices worked with the rods.

 

[gp49]

miniQ update.

Feb. 2 2020, Sunday, was one of these days that Alex and I only heard about from you guys - the old timers. Winds were predicted to be 25 gusting ~40 mph at Coyote. Alex and I, being newbs that have only flown for 2 years, took a handful of our heaviest gliders we had. Weasel's with full ballast , JW60 ~55oz with full ballast, Jaro Muller Ellipse 3Cam and a miniQ of course. On top of the hill we measured the winds at 32 mph, gusting 40!

Alex did not even hesitate and put the miniQ in the air first, after a couple of failed launches. It takes practice to get the 398 gram miniQ airborne in that kind of wind. At the end of the flight Alex got stuck in the turbulent air and was forced to land. The miniQ was relatively easy to fly in these winds. I think I will build a internal ballast box in it just in case we get days like this again. I should be able to put about 100- 150 grams in it. One casualty again after inspecting the Q at home. Even though the tail can separate from the fuse during landings, being hollow, is very susceptible to damage. I have now fixed it twice by injecting epoxy in it. This will be the third time. I will add some carbon tow to the repair.

Below is my attempt at filming the pilot and the Q in this kind of wind - not easy. Sorry for the unsteady hand.

miniQ:

JW60:

BTW, the Weasels did not fly, neither did the Ellipse.