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Old Aug 20, 2012, 09:58 PM
Which one's my plane?
Propbuster1948's Avatar
United States, ID, Caldwell
Joined Oct 2009
171 Posts
Question
New to ducted fans

I am building a 65 inch wing span EDF powered B-57B Canberra using aluminum roofing valley flashing for the intake and outputs. It's very light and rolls into a tube easily. I'm placing the EDF's on center at the wing main spar about 3 inches away from the inlet and tapering the inlet tubes from the intakes 4 inches to the fan's housing size of 3.25 inches. Each EDF with tubes attached weigh 4 ounces. The EDF's are rated, with the inrunners running at 14.8 volts, a Efflux of 217 MPH air speed at the outlets or around 25 ounces of thrust. I checked the fans at 7.4 volts using a single nmh battery and got just over 70 MPH out with 12 MPH vacuum at the input using an anemometer to test. Am I going in the right direction? The entire plane, if all goes well, should come in at under 96 - 120 ounces total weight with everything onboard including four nmh 4200 ma batteries.

Rosie Summerplace
August 2012
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Old Aug 20, 2012, 10:11 PM
Registered User
United States, TX, Grand Prairie
Joined Nov 2005
5,881 Posts
25oz is too low of static thrust for this plane, would be perfect if we had half mile run ways for our planes.

3/4 thrust to weight is great for scale speed and Oh crap situations for edfs...

Looks like you're running 80mm fans (eflights?) You can get 5.5lbs of thrust out of them for 1200 watts 2150kv motor on 6s. A single 5000mah 40+c pack will power them both great for 11lbs of thrust and nice efflux...stay in the air forever if you want because of the light weight.

Make sure to take vids

Any pics so far?

Regards
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Old Aug 21, 2012, 12:43 AM
Which one's my plane?
Propbuster1948's Avatar
United States, ID, Caldwell
Joined Oct 2009
171 Posts
My oh my, I listened to a salesman who told me I could get enough thrust with twin Ammo 24-45-3790 In-Runner Brushless Motor with Hyperflow 370 EP Ducted Fans. It's either shrink the plane or spend more money... shrinking the plane is cheaper. Thank you for your input.

Rosie Summerplace
August 2012

Edit:No pictures, sorry. There may be no flying plane if what you said is correct. I'll probably build a hanger queen just because I like the B-57B Canberra so much.
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Last edited by Propbuster1948; Aug 21, 2012 at 03:22 AM.
Old Aug 21, 2012, 03:24 AM
Which one's my plane?
Propbuster1948's Avatar
United States, ID, Caldwell
Joined Oct 2009
171 Posts
I am so embarrassed. I grew up when Super Tiger was still Como... age does this to people.
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Old Aug 21, 2012, 09:15 AM
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United States, TX, Grand Prairie
Joined Nov 2005
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Quote:
Originally Posted by Propbuster1948 View Post
I am so embarrassed. I grew up when Super Tiger was still Como... age does this to people.
We'll all be there some day...

Finish off the plane....PM me....I think I have a combo for you if you don't want to swing the Eflights...or would like them with another option

Saw pics of the plane, it would make a very very nice model...something different too in EDFs seeing that there are 25 versions of the F16
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Old Aug 21, 2012, 11:26 AM
Which one's my plane?
Propbuster1948's Avatar
United States, ID, Caldwell
Joined Oct 2009
171 Posts
Attachment 5099398

This is all I have left of the B-57B Canberra I built in 1986 - 87. It's fiberglass and has 15 ounces of lead in the nose. It was not a ducted fan, but rather had two OS 32 with props. It crashed after five flights due to engine failure on the low side during a turn with less than one mistake in altitude.

These are the plans I ordered.

http://www.ebay.com/itm/Plans-for-1-...item53ee5f1b5e

I will have to modify the nose for the B model which is what I did with the one I built in 86.

Rosie Summerplace
August 2012
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Last edited by Propbuster1948; Sep 25, 2012 at 02:21 PM.
Old Aug 22, 2012, 03:50 PM
Which one's my plane?
Propbuster1948's Avatar
United States, ID, Caldwell
Joined Oct 2009
171 Posts
I ordered new motors/fans/controllers. Going to be talking with Tower about returning the ones I got. If they say no, then I may build an A-10 foamy or sell the motors/fans/controllers here.
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Last edited by Propbuster1948; Aug 22, 2012 at 03:59 PM.
Old Aug 22, 2012, 04:54 PM
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United States, TX, Grand Prairie
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Quote:
Originally Posted by Propbuster1948 View Post
I ordered new motors/fans/controllers. Going to be talking with Tower about returning the ones I got. If they say no, then I may build an A-10 foamy or sell the motors/fans/controllers here.
Good luck, would love to see some pics of the build....looks really interesting and different
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Old Aug 22, 2012, 05:58 PM
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USA, VA, Alexandria
Joined Oct 2004
376 Posts
What is an nmh battery? You mean NIMH? You will get less weight and better performance from LIPOs. 4 x 4200 mah NIMH will only get you 5V. Not sure where you are getting 3.25 in diameter for the hyperflow fans as they are 56mm dia fans. Way too small the weight.
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Old Aug 22, 2012, 06:34 PM
High Dynamic Thrust
stoneenforcer's Avatar
United States, FL, Mt Dora
Joined Feb 2007
2,312 Posts
someone mentioned 3/4 thrust to weight ratio.
* that is the minimum balance you want for a jet aircraft and thats if your wing loading isnt to bad.

once you get more involved and deeper into jets, you'll find that the more power the better. years later, All my jets are now well over 1:1 and I greatly appreciate the extra power on hand.

build light weight!

looking at those plans. the hyperfly 370's wont even get that bird off a concrete runway.
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Old Aug 22, 2012, 10:50 PM
Which one's my plane?
Propbuster1948's Avatar
United States, ID, Caldwell
Joined Oct 2009
171 Posts
Quote:
Originally Posted by lrb75 View Post
What is an nmh battery? You mean NIMH? You will get less weight and better performance from LIPOs. 4 x 4200 mah NIMH will only get you 5V. Not sure where you are getting 3.25 in diameter for the hyperflow fans as they are 56mm dia fans. Way too small the weight.
Pardon, I had in mind LIPO when I wrote nmh and then missed the 'i' on the keyboard. Everyone has missed a keystroke... at least i hope it isn't only me.

So to answer some of the queries.

1. The outside diameter of the Hyperflow unit is 3.25 inches with a 56 MM fan.

2. Electric flight is new to me so I beg your pardon for misspoken words and descriptions.

So if by some chance I misspoke a description in the introduction, I am new into electrics and especially ducted fans.

I did, in reality, begin building model aircraft when I was 14 years of age, 49 years ago, so I'm not new into building airframes but I was never interested electrics until recently.

Thank you for the warm welcome

Rosie Summerplace
August 2012
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Old Aug 23, 2012, 08:53 AM
Which one's my plane?
Propbuster1948's Avatar
United States, ID, Caldwell
Joined Oct 2009
171 Posts
close thread please
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