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Author Topic: Indoor pylon racing  (Read 1226 times)
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Tiger Tim
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« on: December 08, 2018, 10:40:57 AM »

Does anyone do indoor pylon racing?  I’m looking to get my local club Moreno involved with indoor and competition is one good way to build interest.  I was thinking of going with single cell, semi-scale profile models of about 13” span.  So far I’ve built and thrashed a proof of concept which raised some eyebrows at the last indoor session and hopefully I’ll have version two ready to rock for next week.  I’ll try and get some pics up later.

In the meantime, has anyone else done this?
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« Reply #1 on: December 08, 2018, 10:49:54 AM »

I am intrigued

Sd12
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Tiger Tim
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« Reply #2 on: December 08, 2018, 11:05:20 PM »

Here’s version 1.  It’s a dumbed down profile model of the Goodyear(?) racer Sump’n Else, all in 1/16” balsa sheet.  I picked it because it had a decent nose moment and the t-tail allowed for a simple one piece elevator.  The electronics are out of a Horizon Hobby ultra micro Spacewalker, including motor and prop.  It has just one aileron to save the weight of a second servo or some kind of bellcrank linkage.  The goal was a quick, easy, light, cheap plane that would be quick and exciting to fly laps in a local gym.  A broader goal was to come up with a non-intimidating all balsa project that club members would want to build.  Generally speaking, they think wood is too fragile to use for model airplanes but I contend that when it breaks it breaks into puzzle pieces that are easily repairable compared to foam which crumbles, compresses, and generally just weakens.  I practically grew up in a cloud of balsa shavings, esaki tissue, and Sig dope fumes but I need to remember that most others didn’t.  Anyways, I took it to a flying session last week and it attracted a bunch of positive attention while I also gathered a bunch of data on it.

What I learned:

Balsa is every bit as easy to repair in the field as I had hoped, though it does feel heavier than I expected.  The weight may just be a perception thing especially since the plane is so small.  For the next one I’m thinking of building one in balsa and one in foam for comparison.

Surprisingly the Spacewalker motor and prop weren’t quite enough.  I had to fly the Sump’n Else nearly wide open to maintain good, crisp control.  I think it was a matter of the high wingloading causing it to bleed speed off like crazy when I reduced the throttle and the small motor/prop combo didn’t quite have enough pep to get it quickly back onto the front side of the power curve.  Since it was happiest at top speed I quickly learned I had built in way too much incidence.  Next version will have less incidence and more power.  I’m thinking on the next one I’ll experiment with different props too.

A pleasant discovery was that the single aileron didn’t seem to make it roll off-axis.  The aileron is on the left side because I thought that in doing mostly left turns it would give the least aileron drag.  Turns out that due to the size of it, the upgoing aileron decreases the total lift enough to cause the plane to dive when I roll to the left and climb to the right.  This might be fixable with a bit of an aileron/elevator mix in the transmitter but I’m going to try a right side aileron first.

So what’s next?  The plan right now is to build a profile Sea Fury with single aileron on the right and a motor and prop from a Champ.  At the very least I’ll build one out of 1/16” balsa but I may also build a second one from depron or foam board with the paper removed or a combination of the two.  Hopefully this will encourage others to get on board, I’ll be sure to post any progress I have.
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Tiger Tim
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« Reply #3 on: December 08, 2018, 11:10:02 PM »

Technical difficulties on the attachment.  Take two.
Attached files Thumbnail(s):
Re: Indoor pylon racing
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Rossclements
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« Reply #4 on: December 08, 2018, 11:35:06 PM »

We did some indoor pylon racing at the NEAT fair in NY.
https://www.rcgroups.com/forums/showthread.php?3114488-Indoor-Night-at-NEAT-Downsville-School-Sept-14-15th#post40024018
It shows some of the planes. Mine (miss Losangles) used a super high KV brushed tinywhoop motor, and went like stink. It was the fastest by far, but hard to control. It used a minivapor brick.
Fun for sure!
Ross
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« Reply #5 on: December 09, 2018, 07:34:36 AM »

Do you feel you need an aileron that large? A smaller one located a bit further along the wing may have less pitch effect if you stay with a single aileron.

John
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Tiger Tim
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« Reply #6 on: December 09, 2018, 09:55:06 AM »

Do you feel you need an aileron that large? A smaller one located a bit further along the wing may have less pitch effect if you stay with a single aileron.
It doesn’t need to be nearly that big.  I made it that way because I couldn’t find much info on how to size a single aileron, especially on such a small model.  There was some concern about Reynolds numbers and effectiveness so I went with full span for an easy linkage (that way the horn is down by the fuselage) and a little more than twice the chord I would have used for two ailerons.  I figured that too big would just better demonstrate any drawbacks of using just one aileron and I’m glad I did.  I learned a lot more this way than if I had accidentally made it perfect.
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Tiger Tim
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« Reply #7 on: December 16, 2018, 01:56:38 AM »

Update: I didn’t end up finding the time to build a replacement so I did a couple quick modifications to my Sump’n Else to try and get it to handle better.  I cut the aileron down to about 2/3 span which really helped with the aileron drag and diving issues I was having before.  I still think more power would help get it up on the step as they say and even if I don’t fly flat out it’s nice to have some extra punch in reserve to pull myself out of trouble.

What’s more important is whatever I’m doing must be working because last week someone else made a profile racer to try out some ideas.  This may actually lead to something...
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« Reply #8 on: December 16, 2018, 04:54:29 AM »

There's indoor scale rubber powered FF pylon racing here https://www.youtube.com/watch?time_continue=29&v=JBQCYXHXdtY
For teams of two - a holder and a winder.  I know its not RC but it is real fun.

John M
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Tiger Tim
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« Reply #9 on: December 17, 2018, 02:26:51 AM »

FF pylon racing sounds fun but, well, baby steps.  I wouldn’t love to spark interest in rubber powered free flight in town but I’ll consider it a victory if somebody were to just cut their own materials to build something with.
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vtdiy
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« Reply #10 on: December 17, 2018, 09:58:57 AM »

Tim, discussion about, and lots of planes with, single aileron on foamflyer's website www.foamflyer.info (is he up to 300 planes built yet?). I've built a few of his SO-11's with single aileron, and they flew beautifully.

It's funny, at our last club indoor session I brought in my little Termite motor glider for show-and-tell, and a kit build 3D captain of the indoor airways sauntered over, and looking at my model's half-elevator (on only one side of the stab) chuckled, "That's interesting, you've made an elevator that will roll your plane as well as go up and down!" Clever so-and-so, knew nothing of the long history of free flight and R/C trainer models with successful partial trim surfaces. I just said,"Uhhhhhhh no."

I can't help with the foam vs balsa question, Tim, I like both, and sometimes on the same model! They are just both different and so the structural design is different for each, at least ideally.

As for indoor racing, well we did it back in the fun days (not so long ago it seems) with all manner of ill matched craft, Vapors, Embers, AirHogs, and my typical homemade oddities, repurposed airhog guts in balsa or foam thingies. Usually the last one still flying after probably a minute and a half of hard racing around a broom stood on a chair was the winner!

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« Reply #11 on: December 17, 2018, 10:41:57 AM »

This is a great little idea Smiley I think it might be worth trying direct drive for a faster flying speed? Maybe an 7 or 8mm drone motor depending on the amp draw that the brick ESC can handle.

At some point a basic set of rules would be useful, something like a span limit and possibly a maximum motor or battery size. Just to give guidance for developments...

Jon
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vtdiy
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« Reply #12 on: December 17, 2018, 12:01:38 PM »

I just happened to get some packages of 8.5mm coreless motors and props, and the intent was to do some little indoor planes with them -- I miss the old tiny mosquito like whine of those motors running direct drive in thos airhogs foam bricks vs, in a gearbox, as my Morane and GeeBee Z have now. The Morane's hollow box amplifies the sound, so it's kind of like a machine gun constantly firing. I put up another similar sized foam Trainer One with  a gear driven prop in a wing and fuselage slot, and people were jesting, "Hey no IC engines allowed in the gym!" Oh, the embarrassment!

So, not as efficient, but I think an 8mm direct drive indoor "stealth" pylon racer ought to be the business!

You've definitely got me thinking!
« Last Edit: December 17, 2018, 12:12:14 PM by vtdiy » Logged
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« Reply #13 on: December 17, 2018, 12:07:03 PM »

Hmmmm my only concern is the dangers of injury, even with very small racers. So you might consider limiting the speed through some wing area or wing loading requirement, and say limiting it to just one motor type (like 8.5mm max). It's at least as much fun to race slowly as fast when planes are wingtip to wingtip in a gym. We don't want people ducking or cowering on the sidelines. Uhhh, probably?
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Yak 52
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« Reply #14 on: December 17, 2018, 05:05:13 PM »

... say limiting it to just one motor type (like 8.5mm max).

That's still potentially pretty hot  Grin I have some 8mm motor's that give 55g thrust and draw 5A  Wink
Maybe 6 or 7mm would be better.

Like you say though vtdiy - it's not max speed but skillful flying that would make it fun Smiley
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vtdiy
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« Reply #15 on: December 17, 2018, 05:59:52 PM »

Yak, just curious because I haven't tried the 8.5 mm motors I got yet, and I want to know what to expect, roughly.

Is that 55grams of thrust and 5 amps on a 1S, direct drive? Or is that geared with a hefty prop?

Along with the motors, I also received some 65 mm direct drive props (pitch unknown-- "KingKong" brand?)

Or will I end up with something more modest in static thrust and current draw.

I do use Motocalc, but the specs on this inexpensive coreless stuff is basically unavailable, other than as can size and prop diameter.
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« Reply #16 on: December 17, 2018, 06:58:06 PM »

This is 55g static with direct drive on a 65mm King Kong prop on 1S 200mah. The King Kong is one of the better ones I think although I'd assume the pitch is fairly low for a drone optimised prop.

The motor is the CL-0829-18 Dark Edition from Micro Motor Warehouse https://micro-motor-warehouse.com/collections/all-motors/products/cl-0820-18
I have been running them in for my next E20 but yet to fly one or do any thrust testing myself. However that is what Benedict (the supplier) has told me. The amp draw is massive and they get pretty warm but for an 8 second E20 motor run (Peterborough rules) that's not an issue. Pretty demanding of the battery too.

There's a lot of variation in 8.5mm coreless motors - run of the mill ones should do 25-35 grams of thrust. I have some Banggood Racerstars that do around 35-40g.


Getting back to pylon racing - you would not want to put 5A through a Spektrum brick - I think they can only handle an amp or two.


Jon
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« Reply #17 on: December 18, 2018, 12:06:49 AM »

At some point a basic set of rules would be useful, something like a span limit and possibly a maximum motor or battery size. Just to give guidance for developments...
I agree, though I think at least in my club it will begin as a one-design class since right now I’m doing the majority of development myself.  Once I have something I’m happy with I’ll draw plans and either give them out on flying nights and/or leave a big stack of them at the hobby shop for folks to grab.  And post them online, of course.

The goal remains to come up with something very achievable for anyone, basically meant for the novice builder and intermediate flyer.  Power-wise I’m still leaning heavily towards the park zone receiver brick and 8mm-ish motor and gearbox just because they’re so plentiful.  Essentially easy recycling.  I’m pretty happy with the speed of my Sump’n Else, it’s not impossibly fast but quick and the small size helps give an impression of speed.

At this point I want to get the racer a little more robust, better handling, and even easier to build so development continues...
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Tiger Tim
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« Reply #18 on: December 18, 2018, 12:07:35 AM »

At some point a basic set of rules would be useful, something like a span limit and possibly a maximum motor or battery size. Just to give guidance for developments...
I agree, though I think at least in my club it will begin as a one-design class since right now I’m doing the majority of development myself.  Once I have something I’m happy with I’ll draw plans and either give them out on flying nights and/or leave a big stack of them at the hobby shop for folks to grab.  And post them online, of course.

The goal remains to come up with something very achievable for anyone, basically meant for the novice builder and intermediate flyer.  Power-wise I’m still leaning heavily towards the park zone receiver brick and 8mm-ish motor and gearbox just because they’re so plentiful.  Essentially easy recycling.  I’m pretty happy with the speed of my Sump’n Else, it’s not impossibly fast but quick and the small size helps give an impression of speed.

At this point I want to get the racer a little more robust, better handling, and even easier to build so development continues...
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« Reply #19 on: December 18, 2018, 06:22:15 AM »

Sounds fun  Smiley Look forward to hearing more...

I came across this little kit today:
https://www.banggood.com/MinimumRC-F8F-Rare-Bear-360mm-Wingspan-KT-Board-Mini-RC-Airplane-KIT-With-720-Coreless-Motor-p-1346681.html?rmmds=buy&ID=528923&cur_warehouse=CN
I thought it was quite a bit of gear for the money Smiley
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« Reply #20 on: December 18, 2018, 09:00:10 AM »

Yak,thanks for the specs and your experience! That helps a lot

I guess to fly at lower current as a direct drive, the prop size will need to be downgraded, and so the thrust, too. I guess the only way to really know for my unbranded motors will be to just use my test stand and an ammeter and see what they do.

I don't have a Spektrum brick (well, outside of a working HZ P-51 and a Champ!) but I do have stashed a number of WLToys V911 and WL949 bricks, plus some Lemon DSM connector-less receivers, and some HK 3 amp brushed ESCs.

I've been using 8.5mm motors with the bricks, but geared, with 5" props, and they do pull well, though I'm not sure of the current and thrust at WOT. Must be lower current than direct drive w/those King Kong props, I can't imagine 5 amps through those little brick ESCs but I'm going to have to test if I want to satisfy curiosity.

One way to reduce current, slow the props, so they can be bigger diameter (and more efficient at slow indoor speeds) with brushed motors is to do a multi engine plane with both motors connected in series. For a twin, that halves the voltage each sees, reduces RPM allowing a longer prop to maintain current below max allowable, but there are now two of them pulling, so the total wattage remains the same.

I actually started on a small F-82 with two direct drive brushed motors to check this out. Haven't finished it yet. Because they are brushed you only need one ESC for both, unlike brushless. The fact that two motors are heavier than one is offset by the reduction in weight of eliminating one ESC in a twin. Well, sorry, wandering off topic again. Anyway, may be of interest for a twin engined racer like the De Havilland DH88.
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« Reply #21 on: December 18, 2018, 12:49:18 PM »

I guess to fly at lower current as a direct drive, the prop size will need to be downgraded, and so the thrust, too. I guess the only way to really know for my unbranded motors will be to just use my test stand and an ammeter and see what they do.

I don't have a Spektrum brick (well, outside of a working HZ P-51 and a Champ!) but I do have stashed a number of WLToys V911 and WL949 bricks, plus some Lemon DSM connector-less receivers, and some HK 3 amp brushed ESCs.

I've been using 8.5mm motors with the bricks, but geared, with 5" props, and they do pull well, though I'm not sure of the current and thrust at WOT. Must be lower current than direct drive w/those King Kong props, I can't imagine 5 amps through those little brick ESCs but I'm going to have to test if I want to satisfy curiosity.

I'd expect your generic 8.5mms to draw around 2-3A max. I've measured the Racerstar 8520 static full throttle with a 65mm prop and it takes 2.5A on 1S. Going to a 55mm would drop it to about 2A. (The 5A draw I mentioned is for these particularly hot MMW motors.)

It would be quite possible to set something up without a brick if desired but the 'canabilised brick from a broken ARTF' option is a good one.

Some kind of scale element would be nice for Pylon racers - I've also thought about doing a twin of some kind Smiley A dH88 Comet would be lovely, maybe you could do profile scale racers at 1:20 or 1:24? A bit like Mini Goodyear in Control Line.
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Tiger Tim
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« Reply #22 on: January 03, 2019, 07:34:50 PM »

Some kind of scale element would be nice for Pylon racers - I've also thought about doing a twin of some kind Smiley A dH88 Comet would be lovely, maybe you could do profile scale racers at 1:20 or 1:24? A bit like Mini Goodyear in Control Line.
Well now you have me thinking about twins too.  Lightnings and Tiger Cats and Comets, oh my!
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