r60fan

I'm really interested in ducted fans of the 010 to 049 size, but cant find many finished examples on the web, or much talk about what works and what doesnt. anyone know of some small jet models or tried one?

prole

My Feedback: (3)

hey r60fan,

you're right, there isn't too much on that subject.

a while back in this forum there was a long thread on the fantrainer. Supposedly it was a really good flying plane, that uses a simple .049/.051 TD.

Here is a link to the page where the plans are available -

http://www.rcstore.com/rs/general/li...d=34&catego=PL

It's about 3/4 of the way down the page, I'll put a photo of it here too. Search this forum for "fantrainer" it will show you that thread.

That is about as far as that subject has gone here, it really doesn't come up very much. Every once in a while I'll see one of those RK 709 fans or the RK049's on eBay but they go for a lot of $$$.

What do you know about it, ever done one, I'd love to hear about it.


here is the fantrainer:

soarrich

My Feedback: (98)

My flying buddy did a F-16 for Flying Models when the Kress stuff was new, it just kind of staggered around, not a good flier.

EASYTIGER

My Feedback: (119)

Bingo. Not enough power.
By the way...one of the brit mags had plans for a TD 02 powered homemade fan a few years back. A fellow built 8 for a b52. No lie.

r60fan

wish I had something Prole, just a pair of wings from a wattage f-22 and some ideas for them

the f-22 was really boring but flew ok for always being in a stall condition, maybe I should put my OS 10 on it!!!!

SigKavalier

Yeah I think 1/2a ducted fans are a dead duck. One reason is you need a really hot motor to turn the fan over fast enough. Minimum of 24,000 rpms if you convert an electric fan. Even the Fantrainer is ok on a small glow but stick a brushless electric motor in it, and it screams 100mph+. A guy over at E-Zone converted one. Of course there's still a large price difference between a screaming brushless motor, and a small .049 type motor. The performance gap is huge though. IMHO the small electrics have just far surpassed the small IC engines in power.

soarrich

My Feedback: (98)

Fighting words, I'll help you glove up Dickybird!

Dave Campbell

Sigh..... See, this is why y'all need to start making the annual pilgrimage to Toledo every April. I've got two of these Kress/Midwest RK .049 units-how do you like me now?

I understand that Kress is/was selling a new pusher design 1/2A fan unit. I never followed up on it though.

Yep, the first 1/2A DF's flew like crap, no doubt about it. Remeber also that these were done TWENTY years ago. The airplanes were wayyy heavier than what would be acceptable today in a sport plane and flew with airfoils and design that are archaic by today's standards. Fan design has matured too-look at what the electric fans are doing! They spin the same size fan as an RK-049 and about the same RPM, and go like hell. Just think, if you powered the electric airplane with the RK-049, you wouldn't need the 8oz. in batteries. Now THAT would be something-were going to find out someday when I'm not busy with other stuff!

Dave

SigKavalier

True I'm not saying they wouldn't fly better now than then. Yet a hot .049 thats really screaming say 22-24,000 rpms is the equivelent of a good brushed motor. With less weight true, but here's the catch. A brushless will turn the same fan closer to 30,000 rpm's and there's a huge performance jump there. It's the difference between a decent flight, and consecutive loops with very high speed passes. I can buy speed 400 motors all day long at $8 a pop at the LHS. Hot Norvels are $30+ and tuning etc. If your going to do it just to do it thats one thing, but your only going to see a performance improve, and slight at that over a $8-10 brushed motor. Of course brushless motors do cost $75+ and the controllers are at least that. However they always run, and don't wear out. Short of physical damage or burning one up by exceeding it's limits they will run for 10 years+.
When I see a small electric doing 180+mph there's no doubt where the performance is in the little stuff. However you jump up a couple of sizes, and gas becomes the leader again in bang for your buck. Don't get me wrong it would be cool. You don't have to recharge gas, but I've always had problems getting .049's to run. I'll ask over at E-zone but somebody had posted a link to a new company that makes a Mig-15 kit that fly's off their new fan specially made for the .049 that would be a good place to start.

Dave Campbell

SigKavelier:

I haven't put all the pieces together, but I've got a little background here to go off of regarding 1/2A's and electrics with regards to fans.

The standard Sp400 sized fan is the Wemotec 480. On a brushless 02 and 8 cells you'll see around 21-22krpm at about 19A. The 3 turn 05 brushless will do about 29k at 30A.

One of the first things I did when I got my 480 was put my 020 in it to see what the current draw was relative to my 020 with the 4.7-4.7CAM prop on the same motor and pack. It ended up pulling less current, meaning it spun faster as the voltage under pack load was higher.

Now, porting the logic that the 4.7-4.7 is more load than the 480 fan unit is, If I can take a Cyclon .061 with no timing change or compression change (meant to run on 0% fuel, I used 15%) and get 26,700 on the 4.7-4.7, we are starting to get into the ballpark.

Not only will the RPM rise as the motor is optimized, but that's not with the tuned pipe, not with a lot of nitro, and the 40% reduction in weight will lessen the induced drag considerably, so it would be a lot faster. The Cyclon makes peak HP at 37krpm, so this is very doable.

I didn't have a way to tach it, but I did start converting the earlier Wemotec 400 fan to Norvel power. I cut the inside on a bridgeport, machined an adaptor for the impellor etc, made an aluminum spinner and crescent shape motor mount to fit the original Sp400 tube, just need to find a way to mount it and drill holes for needles and fuel line. Anyway, the motor sounded well into the mid twenties without the shroud on it, which is plenty enough to fly well. We'll find out?

I'm going to bed, I'll post pics later.

Dave

EASYTIGER

My Feedback: (119)

Sounds good, Dave. Maybe cut down the rotor and unload the motor till it gets into that 37000 peak. Also, you need a pipe to make it really shine.

SigKavalier

I dunno I don't know anyone running a speed 400 in a Wemotec 480. I have one sitting here in a F-18 with a AP29L on 10 cells. It's a decent setup thats hand launchable, and has good climb authority. Speed 400 fans are more along the lines of the Vasa 55, or the new Wattage fan. Although GWS has a new one but it's like a big parkflyer fan.
If you can get it to turn 37,000 rpm then I'll be impressed. Lightweight does contribute to speed, but efflux velocity is where you get most of your speed, and you only get high efflux with high rpms. 2,000 rpm in a fan makes a good difference. So if you can match a brushless with less weight then you've got the edge. The engine will be screaming though so heat will be an issue I think. I'm not familier with the Cyclone engines so I don't know. My knowledge consist of a lot of cox engines and a few norvels.
I looked into doing a 1/2a ductef fan awhile back. I looked at the Norvel engines, but the problem is there obviously some trick to get the rpms people were claiming from them. The stock rpm's are not sufficient. Or not sufficient enough to make me want to pull a $8 motor to put in a $40 motor for little gains.

2fast4u

My Feedback: (5)

The guy that designed the Fan Trainer lives here in Little Rock. There were several of them built in the local area and they all ran a Cox TD .051 with the recomended cut down 3-Blade prop. I promiss you they were NOT marginal, they hauled the mail. Inverted passes on the deck, tall loops, high speed passes, the works. The worst thing was trying to start the engine in such a tight space. The best combo I have seen was a NORVEL .061 with spring starter. With 25% nitro or better, it is a bunch of fun to fly!! And easy to start too. (Sorry Dickeybird, but TD's are kinda hard to start sometimes.)

SigKavalier

I heard it flew good but was heavy. I saw video of one on a Mega brushless, and it definitely looked hot. The owner said 100+mph.
Anyway what is the Cyclone .061? I did a search on the net and turned up nothing. All I found was Cox, and Norvel.
I'm still waiting on a reply elsewhere for info on the company that is producing the little Mig-15 kit, and .049 fan.

LoneRanger

My Feedback: (1)

I realy think a .074- .049 DF would be super cool. I think the exhaust would be the key to get good RPM's to pull a larger fan for more static thrust? more pitch in the fan itself-

and with my norvel's the darn muffler is a bit well, BULKY to say the least at least with a DF set up- I think it would severly dissrupt the air flow!

so, how to make a super trick little pipe that was smooth and not bulky-the bend would have to stay right along side the head and not stick out into the airstream at all.




making any sense here?

I like typing.........



L.R.

Dave Campbell

The official Cyclon (not cyclone-that's why you didn't get any search results) is:

www.cyclonengines.narod.ru/\

The US importer is:

http://www.the-printer.net/DookCat.html

GRS Models imports a copy of the Cyclon that is allegedly faster and is also on the web.

These are INCREDIBLY POWERFUL 1/2A motors intended for FF F1J and CL events. They make between .6 and .7hp depending on what displacement you buy, and run on pressure. These motors are made in Novosibirsk, Russia in a defense plant and are several leap years more advanced than any Nelson engine ever was-let alone other 1/2A's. The pics on the website just does no justice to them. They are about $150 which is steep, but you can't get anything nearly as fast in the world. They 'run' right out of the box too..
--------------------------------------------------

When I say Sp400 fans, I mean general diameter class. The 480 fan is nothing more than the earlier 400 version with a one piece rotor. Getting a Norvel into shape for a fan consists of getting the right one, and 20 minutes of fiddling. Even if you were down 2 or 3krpm to a 'hot brushless setup', that electric wonder motor only gives that kind of performance for about the first 30 seconds of the flight and is soo heavy that you need a bungie launcher to get it in the air.

Here's the biggest reason that I think a 1/2A fan is capable of out-doing a fancy electric setup fan: If you put the hottest F5D brushless motor you can buy in the 480 fan you'll see about 60A as your current. The pack voltage will be about 9V assuming 10 1250SCR's. With those numbers (9V is generous) that works out to be 540W. Lets then assume that the motor and controller are 80% efficient, and you'll get 432W to the impeller. 432w is equal to .58hp.

The Cyclon makes .7hp or 522w without the pipe or nitro, and that's at the prop with no efficiency losses along the way as with the electric.

Dave

P.S. On the Norvel, I plan to run no pipe. It would be really tough to make one, i think?

DICKEYBIRD

Hey Dave, I just had a brilliant idea! Why not email a link to one of our better Norvel vs. Cox threads to those Rooskie rocket scientist/1/2A engine designers and tell 'em you need a 40K tuned pipe engine....I'll bet they'd do it just to mess with our heads!

LoneRanger

My Feedback: (1)

HAHAHA that is funny and probably true!

lol

Dave Campbell

Well, they prolly would 'cept gold only comes as high as 24k. Heh.

Dave

SigKavalier

Mmmm someone is missing some electro knowledge. You have your figures right somewhat but are leaving out quite a few motors. Why don't electric guys like Kyosho fans? Because they explode at 600watts of input. As we speak a guy has a electric fan putting out close to 14lbs of thrust. Thats turbine power, and the cells needed to run it aren't too bad compared to the amount of fuel a jet carries. To be specific he's getting 2.4kwatts. There is a Hotbodies A-7 Corsair that has been converted to electric. No bungee and speed was up from the gas version although duration was down. Thats the only thing I don't like about electrics is duration can go from ok to horrible.
The Cyclone sounds like one hot motor with one problem. At $150 for $40 more you could get an Irvine .46 DF motor. Of course some folks don't care. My advice though on that amount of out is if your going to run a cyclone best put it in a HW-609 fan. 90mm fans will be too much as the Toki unit is a 90mm fan with an .18 and it flies nominally. Other car motors have been tried including high rpm racing motors and they couldn't match the Toki.
The Kyosho fan won't take 600w much less the hp equivelent of anything near that + vibrations. The MF480 will only take a little more and I doubt it's going to handle the vibrations. The 609 is about the same size but designed to take much more abuse.
Also there are a lot of EDF's that will take off by themselves. The problem is most bungeelaunch so they don't eat up 1/4th of their flight time taking off.

Dave Campbell

Hmmmm,.... And someone is talking about apples and oranges. I thought we were talking about 1/2A fans relative to their electric counterpart, size for size. I listed what I know to be a mostest power you can fit in a 3" fan in both electric and glow format.

BTW, an HW 609 has about as much relevance to 1/2A flying as 14lb thrusts, Irvine .46's and Toki fans.

Dave

SigKavalier

Duh I was suggesting the 609 as a good fan to modify for 1/2a DF if you were planning to run a hot motor like the cyclone. As was stated it's HP is nearing the 600watts mark if it were an electric motor. Electric motors run smooth, and single cylinder 2-strokes put out vibes. I'm saying that at 530+ watts or that running a cyclone on a Kyosho fan, or a MF-480 with the vibrations produced by the glow motor could cause the rotor to explode mid flight. The 12lbs of thrust was relative to a statement made that electrics are heavy and don't put out much power except for the first 30 seconds.
I was using the Toki .18 and fan as a comparison for finding the most effecient fan for the Cyclone motor. Which your right on as far as what size fan. The HW-609 is basically a beefed up MF-480 designed to take more stress, and watts. You put a plastic MF-480 rotor on a vibrating 2-stroke putting out .7hp+ and you get the rpm's up comparable to a hot brushless. I don't think you'll get more than 1 or 2 runs with that rotor before you'll be digging pieces of fan out of the ducting walls. Once you get past 450watts in that fan ANY vibration will kill it. Whether it's from being off balance or simply shaken to death.
I am however just trying to help.
As far as exhaust go have you considered a Silent Pipe? You could custom make a manifold, and hook it to a silent pipe running through the ducting like a normal DF's tuned pipe does. They aren't buy like $15 and are supposed to improve your HP by a little. They make them for these size engines.
I was not trying to bash 1/2a ducted fans. It however was not known to me that there was a cyclone or that it put out that much power.
540 watts is also not the most power in the MF-480 size. If it was people would not have Kyosho fans exploding at 600 watts.
So thank you and I will be gone now.

EASYTIGER

My Feedback: (119)

Hey, we're just talking here, no hostility intended whatsoever...

SigKavalier

The fly quiet pipe is just a straight tuned pipe with an elastic coupler. they make them for just about all sizes of engines. Also smooth air in to the fan is more important than smooth air out. I'm still waiting for a reply elsewhere on the company that is producing the 1/2a DF kit's and fans. They're new and produce an .049 fan, and a Mig-15 kit. Wasn't very high priced either if I recall.
Instead of throttle maybe just consider a choke? That way you can shoot a couple of landings before dead sticking it in. If you've got enough field it probably won't matter though.
Also I thought of something else. The VASA 55 fan is a speed 400 sized fan. It's a little more pricey than a MF-480 but it is carbon fiber and will hold up much much better.
Maybe just get the Vasa fan and make you own mount, and shroud. Thats if a MF-480 fan cannot take the vibrations.
I belive the new .049 fan I was talking about above is actually smaller than the Vasa fan. So might not be good for the cyclone although I thought other 1/2a DF people might want to give it a shot. $150 for a cyclone is still cheaper than a brushless motor and controller. Although you must understand there's not much 1/2a around here. I've only flown them on U/C's and on glider pods.

SigKavalier

Oh hey sorry to post again but I found the fan for glow I was talking about. Might interest some people.
http://www.kamdax.com/main.html