Where do I get .15 to .21 size ducted fans?
12-31-2002, 10:16 PM
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Where do I get .15 to .21 size ducted fans?
Okay. Well, I have decided after reading numerous posts on this forum, that the expense and hassle of three electric ducted fans to haul my project (KC-10), isn't worth it and I'll just go back to my original idea of using nitro ducted fans. I don't want a 6" fan because if I wanted to make it scale, it would have a 12' wingspan. That would be cool, but it would never leave my house since I have no way to transport something like that. My limit is about an 8' wingspan. I don't want it to be less than a 5' wingspan either. So, that means I need a fan between 2.5" and 4". I've read about the Toki .18, and the Kress fans, but I can't find out where to buy either of them! If I have a KC-10 with a 5' wingspan, I'm guessing I could keep it around 8 pounds. Up to an 8' wigspan, I'll be around 15 pounds I'm sure. I need something capable of hauling it. I don't even know how big the Kress fans are, or the Toki fans. I'm basically going to build my plane whatever size I can find a good reliable engine setup. I'm planning on using all three engines. This is becoming a real nightmare! I hear you can use an OS .21 engine with the Kress fan. What size is the fan and what kind of thrust would I be getting? How hard is it to mount the fan to the OS buggy engine? I'm assuming it's the OS .21 RG-X? This is all getting pretty confusing! PLEASE! Somebody set me straight here! Matt
12-31-2002, 11:59 PM
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Where do I get .15 to .21 size ducted fans?
The Toki is 3.9 in diameter, and does OK with the A-7s at four to five pounds, so I guess the thrust is in the region of two pounds.
Don't forget the foot of tuned pipe that hangs out the back of most glow-powered ducted fans, including the Toki.
Don't forget the foot of tuned pipe that hangs out the back of most glow-powered ducted fans, including the Toki.
01-01-2003, 11:56 PM
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Where do I get .15 to .21 size ducted fans?
Hey Matt,
I don't know if you've done a search for Kress, .21, small ducted fans, toki, etc here on RCU. There's a lot of info. Easytiger is pretty much the master of the Toki/A7 engine. He's done a lot with it and has pretty good success. Look for his name.
Regarding the Kress, I've got 3 of their fans (RK-709, RK-720, and RK-20). The 20 and 720 are for .21 sized. The 720 is 3.5" diameter and gives out 3.5-4lb of thrust depending on the engine used and the % nitro. The 709 is for .09 to .15 sized engines. It gives out about 2.5-3lb of thrust. Don't use the Rk-20. It's an old, outdated fan and is over 4" diameter (not to mention produces less thrust than the 720).
If you want a .21 fan, then Kress is pretty much the only manufacturer (that I know of). They are quite expensive ($140 for the fan only) and need a fair amount of assembly. Also, these are made for the K&B 3.5 engine only. I've modified mine to take other engines, and it's worked fine. For the enignes, I've used an OFNA .21 Hyper with good results. Also, I've used the MVVS .21 with good results.
For Kress' contact info, do a search for Kress and it'll come up more than once. For the Toki fan, I just orderd the fan/engine combo (For $150) from Singapore Hobbies. I haven't used it yet, but have plans for it.
There is the option of using the Kress impeller and making your own shroud and engine mount, which I've seen done.
One thing I'd reccomend (that I should've done in the first place), is get an engine with a recoil start. Otherwise, you'll have to fab up your own starter probe, which I've done, but was a headache. I unscrewed the impellor more times that I started the engine! Check out http://www.rcuniverse.com/showthread...756#post246614 for the wand I did.
Anyhow, I hope this helps. Let me know if there's anything else I can help with.
Russ
[email protected]]
I don't know if you've done a search for Kress, .21, small ducted fans, toki, etc here on RCU. There's a lot of info. Easytiger is pretty much the master of the Toki/A7 engine. He's done a lot with it and has pretty good success. Look for his name.
Regarding the Kress, I've got 3 of their fans (RK-709, RK-720, and RK-20). The 20 and 720 are for .21 sized. The 720 is 3.5" diameter and gives out 3.5-4lb of thrust depending on the engine used and the % nitro. The 709 is for .09 to .15 sized engines. It gives out about 2.5-3lb of thrust. Don't use the Rk-20. It's an old, outdated fan and is over 4" diameter (not to mention produces less thrust than the 720).
If you want a .21 fan, then Kress is pretty much the only manufacturer (that I know of). They are quite expensive ($140 for the fan only) and need a fair amount of assembly. Also, these are made for the K&B 3.5 engine only. I've modified mine to take other engines, and it's worked fine. For the enignes, I've used an OFNA .21 Hyper with good results. Also, I've used the MVVS .21 with good results.
For Kress' contact info, do a search for Kress and it'll come up more than once. For the Toki fan, I just orderd the fan/engine combo (For $150) from Singapore Hobbies. I haven't used it yet, but have plans for it.
There is the option of using the Kress impeller and making your own shroud and engine mount, which I've seen done.
One thing I'd reccomend (that I should've done in the first place), is get an engine with a recoil start. Otherwise, you'll have to fab up your own starter probe, which I've done, but was a headache. I unscrewed the impellor more times that I started the engine! Check out http://www.rcuniverse.com/showthread...756#post246614 for the wand I did.
Anyhow, I hope this helps. Let me know if there's anything else I can help with.
Russ
[email protected]]
01-02-2003, 01:13 AM
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Where do I get .15 to .21 size ducted fans?
KC10 -
I have the RK 20/K&B 3.5 as well as the Toki.18.
The Toki .18 is sold as the Pilot .18/fan unit/tuned pipe combo. It is a much neater unit than the Kress/.21/MACs pipe set up and probably is just as powerful.
I don't know of anyone who has measured the thrust of the two.
Look at http://www.singahobby.com for details. You'll have to send them an Email for details/prices.
I have the RK 20/K&B 3.5 as well as the Toki.18.
The Toki .18 is sold as the Pilot .18/fan unit/tuned pipe combo. It is a much neater unit than the Kress/.21/MACs pipe set up and probably is just as powerful.
I don't know of anyone who has measured the thrust of the two.
Look at http://www.singahobby.com for details. You'll have to send them an Email for details/prices.
01-02-2003, 04:09 AM
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Where do I get .15 to .21 size ducted fans?
Hey ME262/KC10,
Regarding the Kress, I've measured thrust using the MVVS .21 (at about 21500RPM's), and I'm getting just over 3.5lb (with the RK-720). I haven't done anything with the Toki, but from what I hear, that'll give you about 2.4lb thrust. I should clairify my last post, i haven't used the OFNA in the Rk-720, only in the Rk-20. I'm working on fitting it into the RK-720. The spec's on this engine claim about 35000RPM, so I expect the thrust to go up to about 4lb.
I've never measured the thrust on the Rk-20, but figure it's about 3lb. If you contact kress, they'll give you specs.
I agree, that the Toki is much neater. Hopefully there will be more manufacturers starting to follow the Toki and start making smaller engine/fan/pipe combinations.
Anyhow, just my findings.
Russ
Regarding the Kress, I've measured thrust using the MVVS .21 (at about 21500RPM's), and I'm getting just over 3.5lb (with the RK-720). I haven't done anything with the Toki, but from what I hear, that'll give you about 2.4lb thrust. I should clairify my last post, i haven't used the OFNA in the Rk-720, only in the Rk-20. I'm working on fitting it into the RK-720. The spec's on this engine claim about 35000RPM, so I expect the thrust to go up to about 4lb.
I've never measured the thrust on the Rk-20, but figure it's about 3lb. If you contact kress, they'll give you specs.
I agree, that the Toki is much neater. Hopefully there will be more manufacturers starting to follow the Toki and start making smaller engine/fan/pipe combinations.
Anyhow, just my findings.
Russ
