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Old Oct 11, 2008, 02:12 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
5,819 Posts
Quote:
Originally Posted by AmpAce
Dag, I was having the same thoughts as Tex about gearing the prop drive down some with a belt drive. You could turn the scale props with a smaller motor, and probably save some more weight, overall. The belt drive system should also be easier to keep straight, and vibration free, since your connection to the prop shaft would be via a belt. You could just have a straight shaft running through the nacelle, with a bearing at each end, and probably one near the drive sprocket, if it doesn't end up near the end of the shaft. This kind of a system would give you more flexibility as to the size and type of motors you use. I've also heard that a belt drive system for electrics makes a much more realistic sound than a direct drive motor. I've never heard one, though.

There is a wealth of information available from SDP-SI I sent for their free catalogs, and was very pleased with the information and products they contain. Here's a link to their website: http://www.sdp-si.com/

What a magnificant project you have taken on! I remember as a kid, just after WW II, seeing B-36s flying over our house, out in the hills in western Oregon. Sometimes there were as many as six in a formation. The windows in the house would actually start vibrating before you could hear the engines in the house. The flights would usually go over quite low above the hills, so the noise was amazing.

Best of luck with this project, I'll be watching!

AmpAce
AmpAce,
Great seeing you here.
I have tested my motor set up with a AXI 4130 turning a 18-12 3 blade zinger and get the trust and motor time I want, If I needed to turn a bigger prop with a smaller motor I understand that gearing would help turn it. But I don't see the advantage of making the connection between the motor and the prop better. Help me see it. In most case that I have seen the gearing with a belt will add weight over just a shaft and 3 bearings. Also I would have to off-set the motor from the prop thrust line, no big deal as I could mount the motor down (which would give it more air) and then belt drive up to it.

The info you sent looks cool, just keep in mind that moving the motors forward was the only reason I would need to shaft drive it, it does save me about 2.75 pounds but installing belts and gearing may take away the advantage of moving the motor forward, thus making it better to just add the ballast and put the props on the motors direct.

One thing that I just found out is that I can’t move the #2&5, and #3&4 motors to the leading edge, I have an 8’ carbon fiber wing tub, I can still move them up close to the wing tube though. And what is funny is the karma gods must want me to belt drive it, by off setting the motor down in the lower air intake the shaft would clear the wing tube.

I know that I am going to have to make one test nacelle of engine #3 using a direct shaft, and one test nacelle of engine #3 using a belt drive. The reason for #3 is that it would have the longest shafting.

I added a rendering, the bulkheads and truss are read to be cut, but the wing truss needs to be confirmed that it lines up with the wing ribs mounts.

Thanks a ton for the input everyone.

DAG
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Old Oct 11, 2008, 02:46 PM
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North by Northwest
Joined Nov 2003
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Dag,

Just so you know, I haven't actually experimented with belt drives. What I stated in my last post is mostly heresay, imagination working overtime, and just what I've read.

It just seems logical that a belt driving a shaft would be less likely to set up a vibration between the motor and shaft, due to alignment imperfections, than would an end-on coupling of some sort.

As far as weight savings, I was thinking mainly about using brushless inrunners, of a smaller size than the Axi 4130. Some of the better ones are supposed to be quite a bit more efficient than any outrunner, and with the different sizing of sprockets available, could be geared to turn the scale props at whatever RPM needed to get the thrust. My thoughts are that you could probably also get by with smaller battery packs for the same power and duration.

As you noted, the belt drive system does give much more flexibility in locating the motors. Given the shape of the nacelles, though, you might not be able to get the motors quite as far forward with a belt drive, as with an end-on coupling, except where the wing tube is in the way.

Let us know how your tests of the two systems go!

Great project!

AmpAce
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Old Oct 11, 2008, 03:42 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
5,819 Posts
Quote:
Originally Posted by AmpAce
Dag,

Just so you know, I haven't actually experimented with belt drives. What I stated in my last post is mostly heresay, imagination working overtime, and just what I've read.

It just seems logical that a belt driving a shaft would be less likely to set up a vibration between the motor and shaft, due to alignment imperfections, than would an end-on coupling of some sort.

As far as weight savings, I was thinking mainly about using brushless inrunners, of a smaller size than the Axi 4130. Some of the better ones are supposed to be quite a bit more efficient than any outrunner, and with the different sizing of sprockets available, could be geared to turn the scale props at whatever RPM needed to get the thrust. My thoughts are that you could probably also get by with smaller battery packs for the same power and duration.

As you noted, the belt drive system does give much more flexibility in locating the motors. Given the shape of the nacelles, though, you might not be able to get the motors quite as far forward with a belt drive, as with an end-on coupling, except where the wing tube is in the way.

Let us know how your tests of the two systems go!

Great project!

AmpAce
AmpAce
It is really funny, I was about 98% sure of what I was going to use for power, now after inputting some inrunner motors and gearing them 4-1 or 5-1 in ElectriCalc I can say that I am just about back to square one. To be scale I need a 18" 3 blade prop, when I look at gearing it is funny that my 100 power flying time would Calc out to about 3.9 minutes at 54mph, but pull the power back to 65% at 39mph and I get about 13 minutes, that is where I plan on fly at anyway. Thats with a smaller motor and gearing the prop. I have a lot to learn . But at least the parts can get cut out for now and a bunch of building can get done before I have to land on what power plant I am using.

Thanks a ton for your input.

DAG
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Old Oct 11, 2008, 04:04 PM
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Texas
Joined Nov 2005
60 Posts
!/12th scale B-36

Here are a few picture of the B-36 James Anderson is building. I made the glass fuse and molds. Butch
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Old Oct 11, 2008, 06:48 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
5,819 Posts
Quote:
Originally Posted by B Sickels
Here are a few picture of the B-36 James Anderson is building. I made the glass fuse and molds. Butch

VERY COOL

What is the specs on it?
What is its span and projected weight?
What is he using for power?

Thanks, DAG
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Old Oct 11, 2008, 07:45 PM
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Winnipeg, MB Canada
Joined Jan 2000
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DAG: If you would like to [1] decrease weight of the power source and [2] increase the flight time, then geared/belted high kv inrunners is the way to go. I have used the 41 series AXI's and they're OK. But get into the high end inrunners and you'll be miles ahead. I have four MaxCim motors but unfortunately Tom is in hyatus, but Steve Neu [NeuMotors] would be where I'd put my money for a project of this importance. From what I've heard he will probably help you with the settups. Tex.
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Old Oct 12, 2008, 02:30 AM
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Old Oct 12, 2008, 07:19 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
5,819 Posts
Quote:
Originally Posted by Sabrejock
DAG: If you would like to [1] decrease weight of the power source and [2] increase the flight time, then geared/belted high kv inrunners is the way to go. I have used the 41 series AXI's and they're OK. But get into the high end inrunners and you'll be miles ahead. I have four MaxCim motors but unfortunately Tom is in hyatus, but Steve Neu [NeuMotors] would be where I'd put my money for a project of this importance. From what I've heard he will probably help you with the settups. Tex.
Tex,
This old dog is learning new tricks. Been a control line and RC gas guy for over 30 years.

Looks like it will 110% be a geared combo. The weight saving is big, also if I re-design the wing to have 2 wing tubes I can still shaft drive the geared motor from the front of the wing going between the tubes. Looks like if I used a Neu combo and Lipo’s I will only be spending about an extra 5% on power and batteries, be nice if I could find a qty discount for buy 6 motors, 6 Speed controllers, and 6 Lipo's.

This re-design of the wing will set me back some, but making this plane stay at under 55 pounds will give it a wing load under 26oz. This plane will chug along and look pretty cool fly a more scale (slow).

Wish I could get the motor direct from Neu, not to sling mud, but I have left 3 voice mails at the place that distributes their motors and never get a response. You would think that a guy going to spend 2.5k on a power plant would get a call back. Hopefully I can find what I want from a dealer or on line. Or if I contact Neu direct they can tell me if the set-up I have put together is the best then just order it on-line from their distributor.


Thanks, DAG
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Old Oct 12, 2008, 09:56 AM
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Texas
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The wing span is about 236". The fuse is 165". The weight is "one heavy mother". It has 6 Quadra's with 3 bladed props. James has been setting on the project for awhile, hope he gets back on it soon. I told him I would make a glass wing if it would get him back interrested in the project. A glass wing would be much lighter and stronger.
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Old Oct 12, 2008, 12:52 PM
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North by Northwest
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Dag,

I think you are wise to take some time and look around to see just what motors are available, and will work best in your application. I haven't personally used them, but Neu motors have a great reputation, and I understand that they can build just about any configuration you might need. I've also read that Steve Neu is very good about providing help to customers, especially for a special project like yours. Sorry, I don't know how to contact him direct.

I'm not sure just how much experience they have with Neu motors yet, but Castle Creations, makers of excellent speed controls, are now carrying them. They have been very good to me about customer support questions, so might be able to help you. Here's a link to Castles Neu Motor Page: http://www.castlecreations.com/produ...motors/nm.html

This project is going to be great fun to follow!

AmpAce
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Old Oct 12, 2008, 01:05 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
5,819 Posts
Quote:
Originally Posted by AmpAce
Dag,

I think you are wise to take some time and look around to see just what motors are available, and will work best in your application. I haven't personally used them, but Neu motors have a great reputation, and I understand that they can build just about any configuration you might need. I've also read that Steve Neu is very good about providing help to customers, especially for a special project like yours. Sorry, I don't know how to contact him direct.

I'm not sure just how much experience they have with Neu motors yet, but Castle Creations, makers of excellent speed controls, are now carrying them. They have been very good to me about customer support questions, so might be able to help you. Here's a link to Castles Neu Motor Page: http://www.castlecreations.com/produ...motors/nm.html

This project is going to be great fun to follow!

AmpAce
Thanks AmpAce,
I know Castle has the best speed controllers, but I got a name from a guy at SR batteries that was helping me with my harnesses and batteries to call at Castle about working out what controller would work best and left the guy 3 messages and never heard a thing. Not very impressed.

I am going to try to reach out to Steve Neu and see if he can help me with a wish list of what I really need. After looking at the fact I can turn a larger prop with a gearbox I may take the B-36 back to the 256” size and forget about the 55 pounds, this project has kind of been my mother of all projects and should build it all out. At 256” I may still be able to hit 55 pounds, but my calc’s show 62 pounds.

Thanks,
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Old Oct 12, 2008, 02:07 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
5,819 Posts
Quote:
Originally Posted by B Sickels
The wing span is about 236". The fuse is 165". The weight is "one heavy mother". It has 6 Quadra's with 3 bladed props. James has been setting on the project for awhile, hope he gets back on it soon. I told him I would make a glass wing if it would get him back interrested in the project. A glass wing would be much lighter and stronger.
Thanks for the specs,

That is the same as mine, I have seen 3 guys try to do the b-36 and keep it under 100 pounds with gas, all of them ended up with over 25-35 pounds of ballast in the nose, that why I went the direction I did with electric. Would love to know how you get your glass so light. I use balsa and carbon fiber tape then cover with ultracote and paint. All of the 50% planes I have built that had glass fuses were 10-15% heavier that wood, I had a 50% Pitts S-1 that I saved 6 pounds on by building my own built-up wood fuse, wish I knew your secret.

My fuse will have the inboard part of the wing built into it so it can set on it's gear when the wings are off it.

Thanks,
DAG
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Old Oct 13, 2008, 10:07 AM
Vintage Flyer
Indiana
Joined Jan 2005
1,674 Posts
Hi Dag and everyone else!
Here's a picture of my giant scale B-17, and it's mostly an electrically operated airplane by the way!
Man those electric motors were a BEAR to INSTALL, and you should see my BATTERY PACK!!!!!
Notice the bomb bay, those are really m Lipo batteries, neat way to conceal them eh?
Easy access to get them in and out!
Actually they plug in with a big auxillary charging cord.
The car is to just give you an idea of the scale! LOL!
Okay Dag, let's see you build that B-36 to match the size of my B-17!! LOL!!!

Ed
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Old Oct 13, 2008, 10:21 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
5,819 Posts
Quote:
Originally Posted by Ercoupe Ed
Hi Dag and everyone else!
Here's a picture of my giant scale B-17, and it's mostly an electrically operated airplane by the way!
Man those electric motors were a BEAR to INSTALL, and you should see my BATTERY PACK!!!!!
Notice the bomb bay, those are really m Lipo batteries, neat way to conceal them eh?
Easy access to get them in and out!
Actually they plug in with a big auxillary charging cord.
The car is to just give you an idea of the scale! LOL!
Okay Dag, let's see you build that B-36 to match the size of my B-17!! LOL!!!

Ed
Hey Ed,
Great to see you here.

Well I did think about making one close to that size, but the 6,955 LiPo packs were to hard to charge LOL, and the 30hp 3 phase 480 motor would not swing my 3 blade 19' prop.

I do have some news though, I have re-scaled my Balsa Overcast back to 258" It will take me about 3 weeks to get the nacelles re-designed around in-runner motors, but fuse work will start this week end .

The 1919 had some problems that seemed to go away once I got the wings on, but if she never flies I might see if the EAA museum would want it.

Is that the 17 that was at Purdue and Mt. Comfort?

Take care,

DAG
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Old Oct 13, 2008, 11:30 AM
Born with hollow bones.
TRWXXA's Avatar
VHP VOR R-318/D0.6
Joined May 2008
191 Posts
Hey Dag!

Can't wait to see the completion of this project. Where do you fly, Muncie? I'm over in Zionsville and would love to see it fly in person.

Ed,

I like your Mustang (and your B-17 ). I have a '93 SSP that I enjoy playing with.
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