Dumb question: FrSky telemetry receivers.

If you've been building electronic bits or modifying stuff you've bought then tell us all about it here. A good place to discuss the installation of 2.4GHz DIY modules too.

Re: Dumb question: FrSky telemetry receivers.

Postby Sid Sideslip » Wed Aug 10, 2011 1:00 am

disco stu wrote:I'm pretty sure it was the 2836 1000kv I got also. Thanks for the info guys

One thing I noticed was that mine came with a metal plate infront of the motor on the outside of the firewall, is that the way they all came or is it a newer addition? I had the thought that some aluminium can around the motor might help dissipate some of the heat produced there


Yeah, mine has that plate too, I think they've always come with that, not sure though.

From what people have said, the 2836 motor works real good; also being a bit thinner it leaves more room for air to get around the motor or alternatively, to fit some glass reinforcement on the inside as well as outside of the nose.

Image
One pic from the RcGroups thread showing glass reinforcing on the outside. The plastic fuse there doesn't like getting hot and can soften up. Notice though that at the cost of some drag it would be possible to put some slots near the rim of the nose to let air in. I think the existing slots at the side of the motor probably don't do much.

So, the main problem is getting some airflow over the motor, no matter what you use.

Another idea I had would be to fit a tiny coke-can impeller behind the spinner that would pump in air and drive it through three or so slots over the motor, then vent it out through a wide faired slot at the back of the canopy and/or drill a hole in the end of the fuse under the tailplane. The impeller would only work when the motor was going and be shielded by the spinner when not, so as to reduce drag. Not sure if the motor shaft is long enough to fit one though.

Whatever, it's fun coming up with ways to change things... and anyway, as Shotgun says, the motor is really only there to get you up for gliding, or get you out of the poo if you are slope soaring and get caught in a downdraught "rotor" or something. But it would be cheeky to cool the insides so you could go balls to the wall. :lol:
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Re: Dumb question: FrSky telemetry receivers.

Postby disco stu » Wed Aug 10, 2011 12:01 pm

I was thinking of some scoops over the vents, and also mounting a can style thing around the motor. Direct the feed from the scoop into the can surrounding motor, then a venturi or 2 behind that plummed in to take the air out. Or just put a few hole behind servos etc. THoughts?
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Re: Dumb question: FrSky telemetry receivers.

Postby Sid Sideslip » Thu Aug 11, 2011 7:39 am

disco stu wrote:I was thinking of some scoops over the vents, and also mounting a can style thing around the motor. Direct the feed from the scoop into the can surrounding motor, then a venturi or 2 behind that plummed in to take the air out. Or just put a few hole behind servos etc. THoughts?


Small scoops would work, but they need to be ahead of the motor to cool it...also, apparently the general rule with ventilation is to have the exit about four times the area of the entrance.

However because other people have had similar problems and done some thinking about it, you can buy "turbo" folding prop spinners with a central hole that probably works OK too. As I'm new to electric assist gliders, so I'm new to such spinners.

From a google image search.

Image
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Re: Dumb question: FrSky telemetry receivers.

Postby disco stu » Fri Aug 19, 2011 12:25 pm

I'm new to these things also. Thanks for the help, didn't know that stuff
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Re: Dumb question: FrSky telemetry receivers.

Postby Sid Sideslip » Fri Aug 19, 2011 10:05 pm

disco stu wrote:I'm new to these things also. Thanks for the help, didn't know that stuff


No problemo.

I had trouble sourcing a headless or "turbo" spinner, as HobbyKing ones are all on backorder and all the ones I found here in Oz were the wrong size.

So I ordered this one, together with some carbon blades from Northeast Sailplane Products in the US.

http://www.nesail.com/detail.php?productID=2908

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Re: Dumb question: FrSky telemetry receivers.

Postby kaptain_zero » Sat Aug 20, 2011 3:13 am

Wow... I would have just reached for my handy dandy drill, hacksaw, dremel tool or hand files....... Those spinners do have that "finished" look though.... not the "It may have survived the last crash..... barely" look, my spinners usually have.

I must say though, after witnessing a couple of chaps from Maacmen fly their Thermal Gliders at the Gimli Model Fest, I've been grumbling a bit about maybe going to the dark side and building a glider without a <gulp> motor. After a quick bungy cord launch, both gliders not only gained some serious altitude, but one was having a spot of trouble getting back down! I suppose one of the benefits of living on the Prairies in Canada is that we have plenty of thermals in the summer... but it's a 2 day drive to anything taller than an ant hill.

On the other hand... thermals get a little sparse around here during the 10 months of good sledding weather that we have. -40C is just not good for thermals... or for listening to low flying C-130's landing at the Winnipeg Airport. I swear those props are RIPPING the sky apart at those temps as they are ear piercingly loud when it gets below -35C.

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Re: Dumb question: FrSky telemetry receivers.

Postby Sid Sideslip » Sat Aug 20, 2011 8:06 am

kaptain_zero wrote:Wow... I would have just reached for my handy dandy drill, hacksaw, dremel tool or hand files....... Those spinners do have that "finished" look though.... not the "It may have survived the last crash..... barely" look, my spinners usually have.


Well, I could have just bought a cheap standard alloy folding prop spinner and modded it on the lathe (or even machined one from scratch) but I couldn't be arsed, tbh. ;)

Image

kaptain_zero wrote:I must say though, after witnessing a couple of chaps from Maacmen fly their Thermal Gliders at the Gimli Model Fest, I've been grumbling a bit about maybe going to the dark side and building a glider without a <gulp> motor. After a quick bungy cord launch, both gliders not only gained some serious altitude, but one was having a spot of trouble getting back down! I suppose one of the benefits of living on the Prairies in Canada is that we have plenty of thermals in the summer... but it's a 2 day drive to anything taller than an ant hill.

On the other hand... thermals get a little sparse around here during the 10 months of good sledding weather that we have. -40C is just not good for thermals... or for listening to low flying C-130's landing at the Winnipeg Airport. I swear those props are RIPPING the sky apart at those temps as they are ear piercingly loud when it gets below -35C.


We have good thermals here in the warmer months, but being in the "roaring 40s" (like Bruce in NZ) it tends to be wind that dominates. Also Tassie is very mountainous, so there are lots of places to fly slope gliders (well, not so many without trees or rocks everywhere) which I prefer, as it's much like having a tame albatross at your beck and call (says me, who hasn't flown slope soarers for over thirty years). Loads of fun. Mind you, I am tempted to build a mean, lean 3 metre carbon fibre based thermal glider too, they are just so......nice. :)
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Re: Dumb question: FrSky telemetry receivers.

Postby kaptain_zero » Sat Aug 20, 2011 4:58 pm

Sid, if that's your home hobby lathe..... you deserve to crash your first turbo spinner! Just kidding of course, but I'd be sorely tempted to do some awful things, if the prize were as sweet as that lathe! I used to work as a gunsmith and had a full machine shop at my disposal... Even after I moved on to my current job, I was welcome to stop by the old shop and use whatever machinery I wanted. Now the shop is gone and I have no friends in that line of work, and the only things in my garage are woodworking tools.

It's gotten to the point that I'm wondering why I purchased a dust collector.... it seems ALL my woodworking tools are gathering dust, all by themselves.


Sid Sideslip wrote:Well, I could have just bought a cheap standard alloy folding prop spinner and modded it on the lathe (or even machined one from scratch) but I couldn't be arsed, tbh. ;)
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Re: Dumb question: FrSky telemetry receivers.

Postby Sid Sideslip » Sat Aug 20, 2011 9:53 pm

kaptain_zero wrote:Sid, if that's your home hobby lathe..... you deserve to crash your first turbo spinner! Just kidding of course, but I'd be sorely tempted to do some awful things, if the prize were as sweet as that lathe! I used to work as a gunsmith and had a full machine shop at my disposal... Even after I moved on to my current job, I was welcome to stop by the old shop and use whatever machinery I wanted. Now the shop is gone and I have no friends in that line of work, and the only things in my garage are woodworking tools.

It's gotten to the point that I'm wondering why I purchased a dust collector.... it seems ALL my woodworking tools are gathering dust, all by themselves.



That's was my lathe. 36" gap bed Chinese jobby. I've had two Chinese lathes and both were damn good, surprisingly. The only problem with this one was the gear change levers on the Norton 'box, which were a pain to use. So I just took the faceplate off and used a pencil to slide the gears around when I was using power feed or screw cutting.

Btw, my father was a fitter and turner who did his apprenticeship with Hobsons in Wolverhampton and then worked for Rolls Royce (aero engines) in Derby during WWII, so we always had a good workshop at home and he taught me how to use it all. My granddad was a railway engineer who worked at the big locomotive shops in Birmingham, so it runs in the family, I guess.

I used this mostly for musical instrument making (uilleann pipes, flutes, oboes etc) with wood rather than metal turning, though of course I made all the tapered reamers and such on this, or the earlier lathes I had.

I had to give it up when I developed COPD; the wood dust, even with protective gear and a dust extractor was too irritating. I sold that lathe a couple of years ago when we needed a new car. These days I just pop round to my brother in law's 'shop and use his, if I need to turn something up.

I got quite depressed about it all for a while and my 'shop just decayed along with me. So it's been fun to get back in there, clean it all up and turn it into a toyshop instead. I should put a sign on the door, "Elves only!" :lol:
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Re: Dumb question: FrSky telemetry receivers.

Postby disco stu » Sun Aug 21, 2011 5:02 am

Just reminded me of a little warry:

Was in a local wrecking yard, and there was this humoungous engine valve sitting on the counter, stainless. I was a bit gobsmacked and asked what on earth that came out of as I wondered how you would fit in any normal head it was that big. They said they had no idea for years and years, then one day this old pom was in there with his son or something, saw this valve and his whole face lit up while reading the numbers etc. He worked for Rolls Royce during the war, and it turned out it was out of a Merlin V12. Had a good look and play with that valve, nice little piece of history!!

Thinking about the cooling spinners, I was thinking that you could easily put some little mini scoops on the spinner that scooped in the air while motor was running-angled for the direction of spin if you know what I mean
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