RC prop Help a first time builder

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billj

Member
Joined
Jun 1, 2016
Messages
16
Location
Virginia
Looking for help mentors in building a prop for an RC airplane..
I have a duplicating router and am hoping to recreate a prop I just broke.
But more importantly a prop of different
Proportion.
I have many props but working at scaling to meet my needs.
48 "x 14
For those unfamiliar..this is Giant scale in the RC world.. That's 65% of full size
420cc with a 1:2.7 reduction.
Here's a pic of my project. Im new here..looking forward to meeting new aviation buffs and craftsmen. 20220825_190957.jpg
 

Bille Floyd

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Joined
Sep 26, 2019
Messages
817
What engine is it , that you use ? It looks perfect for
powering my 14.5m Atos glider !!

Nice RC airplane !!! Biggest one I have , is a 91" Slick ; with
a Da 70 up front.

Bille
 

billj

Member
Joined
Jun 1, 2016
Messages
16
Location
Virginia
What engine is it , that you use ? It looks perfect for
powering my 14.5m Atos glider !!

Nice RC airplane !!! Biggest one I have , is a 91" Slick ; with
a Da 70 up front.

Bille
Thats a zdz 420 4 cylinder with a factory prop reduction drive..
65% Dr 1 top wing is 16ft..about 120lbs
Stands abut 6.5 ft on 19inch bike wheels
 

billj

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Jun 1, 2016
Messages
16
Location
Virginia
That's an ARF..but had to modify alOT
To accommodate that engine..you might notice from picture it's mounted upside down..to use reduction
Moved firewall bak about 8 inched..
Quite a bit of fabrication to keep everything sturdy
 

wsimpso1

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Saline Michigan
You do realize that this forum is about human-rated ships. More power to you if you get good help, but this might be low yield territory.
 

TFF

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Memphis, TN
You have to know which way you want to go with the prop. 48x14 is that a flying prop that broke?what do you want to change? If it loads the engine ok, you can shuffle the numbers to 50x12 or 46x16 and have the engine strain similar, but with changes in performance like speed or climb. If the prop is too big or small for the engine, you are going to have to make an educated guess on the change.

I don’t have anything that big either. I do WW1 in normal RC sizes.
 

billj

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Joined
Jun 1, 2016
Messages
16
Location
Virginia
You have to know which way you want to go with the prop. 48x14 is that a flying prop that broke?what do you want to change? If it loads the engine ok, you can shuffle the numbers to 50x12 or 46x16 and have the engine strain similar, but with changes in performance like speed or climb. If the prop is too big or small for the engine, you are going to have to make an educated guess on the change.

I don’t have anything that big either. I do WW1 in normal RC sizes.
The broken prop was 45 by 12 I think a calculation 48 by 14 might be ideal
 

samyguy

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Sep 19, 2011
Messages
167
Location
74FL Monticello FL.
how many hours run time do you think you could get from this motor ??

what thrust values are you wanting to get ? Pounds of pull ??
 

Victor Bravo

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Wow, that's one hell of a triplane. If that's an ARF then how much further would it really be for the same company to offer an ARF MiniMax or HiMax? Hmmm...

When "Giant Scale" started, the first one I ever saw around here was the Bud Nosen Mr. Mulligan, about 8 or 9 feet span, and they put an O.S. .80 engine on it. That was really marginal, and soon the first Quadra weed whacker engines came into use, and Giant Scale took off. There also used to be the Wes-Craft B-17, which was about 7 feet IIRC, that used four .40 or .60 size engines. This is like 1975-77 from dim memory.

I guess I'm dating myself here...
 

cblink.007

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K2W6, Maryland, USA
Not to plug a product(s), but if you're aiming to design a prop, Flow5 and FreeCAD might provide good platforms for the design & analysis pieces.

But for good mentorship & education, I'd say talk to the folks at Sensenich....and especially Catto; I know Craig Catto has done a number of customs over the years...he may even have some of the answers you are seeking!

 

billj

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Jun 1, 2016
Messages
16
Location
Virginia
how many hours run time do you think you could get from this motor ??

what thrust values are you wanting to get ? Pounds of pull ??
I've never heard of one of these engines wearing but I would guess the rebuild would be over 100 hours

I saw the 500cc version to this mounted on a bd5
I'm hoping for around 100 pounds of thrust the plane raised around 120
 

wsimpso1

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You realize that many ultralight aircraft fly on 48 to 50 inch propellers

I did look - 49” diameter is the small end of ultralight props, although powered parachutes do go a little smaller. I was not trying to discourage you, just putting out the caution that, as terrific as this bunch is, it might not be the help you need…
 

billj

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Jun 1, 2016
Messages
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Location
Virginia
I did look - 49” diameter is the small end of ultralight props, although powered parachutes do go a little smaller. I was not trying to discourage you, just putting out the caution that, as terrific as this bunch is, it might not be the help you need…
Right now, everything is appreciated...the process is the same..large or small...
Bit under the weather today...a
I apologize for he sharpness
 

billyvray

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Aug 17, 2005
Messages
1,028
Location
Newnan, GA
Sweet project, internet friend. I have no experience with these vendors but I would give them a call:


They deal in smaller props for airboats and hovercraft.
 

Victor Bravo

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billj, fron just one post and the accompanying photograph we can see that you have a nice little shop out in the Virginia country that's at least large enough for a 16-20 foot span aircraft, a couple of bottles of CA glue (with a commensurately high probability of saws, knives, and sandpaper nearby), a small 30-40HP two-stroke engine (currently being stored on a dirt bike), woodworking tools and the means to carve at least a four foot propeller, and a Giant Scale interest in antique airplanes with more than one wing.

Soooo... on behalf of our entire homebuilt airplane forum here (and with a particular tip of the hat to one of our members who just happens to be a senior executive at the Staaken Flitzerwerke Verein)... I may have a little proposal for you :)

editor_images%2F1523883668451-Flitzer02.jpg
 
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Bille Floyd

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Sep 26, 2019
Messages
817
You realize that many ultralight aircraft fly on 48 to 50 inch propellers

You have the ZDZ 420 quad ; my 14.5m, Atos glider would fly just fine
on the 27lb, 40hp , ZDZ 3904-j , with reduction. I got a price for it ; but
can't afford it. :(
ZDZ also makes a 25hp twin, with starter and reduction , which would
also get my rigid-wing glider off the ground, at 5500 ASL ; it was
made for PPG , and weighs under 30lb.

Bille

 

billj

Member
Joined
Jun 1, 2016
Messages
16
Location
Virginia
Wow, that's one hell of a triplane. If that's an ARF then how much further would it really be for the same company to offer an ARF MiniMax or HiMax? Hmmm...

When "Giant Scale" started, the first one I ever saw around here was the Bud Nosen Mr. Mulligan, about 8 or 9 feet span, and they put an O.S. .80 engine on it. That was really marginal, and soon the first Quadra weed whacker engines came into use, and Giant Scale took off. There also used to be the Wes-Craft B-17, which was about 7 feet IIRC, that used four .40 or .60 size engines. This is like 1975-77 from dim memory.

I guess I'm dating myself here...
Only weighs 120lbs. More fragile than you'd think in some circumstances
 
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