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May 21, 2019, 02:36 PM
EB-66C Team Member
J Morgan's Avatar
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I've read that too Nut. Amazing.

Rodger,
Thanks, pretty sure it will have a unique sound.

Mike,
Thanks, appreciate it. You should try it, if you enjoy building I think you would find it hard not to enjoy this type build.

Just finished up with the port side, making stands so I can work on the other now.

J
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May 21, 2019, 03:42 PM
EB-66C Team Member
J Morgan's Avatar
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Weighed the first half, weighs 9.5 oz but that is with the keel still in there and the inner pieces of the formers. Most of that will be removed as I skin the other half.

J
May 21, 2019, 11:38 PM
Registered User
p901P901's Avatar
Here is the set up I did a few years ago. ESC's were not calibrated, that is why the props do not start at the same time. Motors are PROPDRIVE 4248 650KV. More prop pitch changes were made after this video to increase thrust. Distance between props also helps to increase thrust. Different rpm between motors can be done by having different max throttle calibrations. Try to get both motors to pull the same amperage.
Custom contra rotating running (1 min 1 sec)
Last edited by p901P901; May 22, 2019 at 12:00 AM.
May 22, 2019, 06:03 AM
EB-66C Team Member
J Morgan's Avatar
Thread OP
Quote:
Originally Posted by p901P901
Here is the set up I did a few years ago. ESC's were not calibrated, that is why the props do not start at the same time. Motors are PROPDRIVE 4248 650KV. More prop pitch changes were made after this video to increase thrust. Distance between props also helps to increase thrust. Different rpm between motors can be done by having different max throttle calibrations. Try to get both motors to pull the same amperage.
https://www.youtube.com/watch?v=YDKUsTkUIoY
Interesting. I like how the thrust is moving the table.
Did you find that one of the props ( either front or back) needed to be less diameter and pitch to give more efficiency?

J
May 22, 2019, 06:41 AM
Registered User
p901P901's Avatar
I tried several combinations with diameter and pitch. If the motor rpm are the same then go with more pitch in the rear. I was looking for thrust and never measured efficiency. Max thrust was when both motors ran the same amperage.
CCW 2 bladed props are hard to find with the right pitch combinations. 3 bladed prop combinations will be difficult to find over 18". The rear prop may need reamed out over 1/2" to go over the front motor adapter. So look for IC CCW props because of the larger hubs.
May 22, 2019, 11:11 AM
EB-66C Team Member
J Morgan's Avatar
Thread OP
Quote:
Originally Posted by p901P901
I tried several combinations with diameter and pitch. If the motor rpm are the same then go with more pitch in the rear. I was looking for thrust and never measured efficiency. Max thrust was when both motors ran the same amperage.
CCW 2 bladed props are hard to find with the right pitch combinations. 3 bladed prop combinations will be difficult to find over 18". The rear prop may need reamed out over 1/2" to go over the front motor adapter. So look for IC CCW props because of the larger hubs.
Thanks very much for the info. Presently I'm looking for 16" props, probably square the tips a little to give a better "look". I have a Graupner 16x12x3 tractor and a MAS 16x10x3 pusher that I was hoping would work. Guess testing will be the only answer.

J
May 22, 2019, 12:33 PM
Registered User
Wow.... Stand back and duck when those 16"s get moving.

Incredible project, John.

Den
May 22, 2019, 01:31 PM
Registered User
Trying to figure out how this works.
The motor behind the firewall drives the front most prop, with a shaft that runs through the motor in front of firewall and inside the front motors driveshaft? And the inner drive shaft is supported by bearings somewhere I guess?
May 22, 2019, 02:08 PM
EB-66C Team Member
J Morgan's Avatar
Thread OP
Thanks Den,
Yep, probably gonna be a bit scary.

Jim,
Yes, that's it in a nutshell.

Got a little done before starting my lawn work. Removing the inner structure as I add more skinning.

J
May 22, 2019, 03:23 PM
Classic jets rule
AIR SALLY's Avatar
Man you are making quick work of the fuse .
do you remove the whole Keel or just cut out the areas you don't need . think I can still see it ...the white foam?
May 22, 2019, 04:25 PM
Registered User
p901P901's Avatar
Quote:
Originally Posted by JimF
Trying to figure out how this works.
The motor behind the firewall drives the front most prop, with a shaft that runs through the motor in front of firewall and inside the front motors driveshaft? And the inner drive shaft is supported by bearings somewhere I guess?
There is an custom adapter that attaches to the front motor's rotor. This has bearings inside that supports the rear motors lengthened shaft. The rear prop goes on the front motor's adapter and is held in place with a nut. The rear motor's shaft has a prop adapter that the front prop attaches. The front motor's rotor is drilled out larger than the old shaft dia.. So its no longer supported by the shaft when doing this modification. The adapter now is the support.
Last edited by p901P901; May 22, 2019 at 06:28 PM.
May 22, 2019, 04:45 PM
EB-66C Team Member
J Morgan's Avatar
Thread OP
Quote:
Originally Posted by AIR SALLY
Man you are making quick work of the fuse .
do you remove the whole Keel or just cut out the areas you don't need . think I can still see it ...the white foam?
I leave about an inch perimeter of the white keel, the skins are glued to it. I started out with white MPF and when it got down to the compound curves,
switched to my first love, fanfold. I love this stuff. I don't like working with Depron so not upset that it's gone. I never liked having to lay a bunch of tape down just to make a simple curve. MPF is better but still no where close to the workability of fanfold. Yeah, it's a PITA getting the plastic film off the one side but with a lot of experience and some patience it can be done w/o much trouble. I'll be finishing the fuse with fanfold and switch back to MPF for the wing since I don't need any tight curves.
Hopefully I can finish this fuse skinning tomorrow.

J
May 22, 2019, 05:20 PM
Registered User
p901P901's Avatar
Nice!

Always liked foam building.

Depron skinning was nice to work with, but now its with poster board with the paper removed.
May 22, 2019, 07:07 PM
Registered User
Really fast and nice work.

D
May 22, 2019, 09:39 PM
When cows fly!
Wow! As always I will be


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