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Old Aug 01, 2013, 10:34 AM
Zor
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Ontario,Canada
Joined Feb 2007
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For the general reader

Hello everyone,

I have ended the discussion with whiskykid.

The following comments are based on experimentation and observation.

1- Look at a prop that is at rest (not turning) with an eye in the plane of rotation. Yes you see the back of the prop blades due to their angle of attack.

2- Where would a blade go if detached for any reason while turning at thousands of rpm ? Prop blades have detached at high rpm particularly the props that have folding blades as often used on sailplanes.

Experimentation I made as follows _ _ _

Using a folding blade propeller I filed the material so that the blades stop allowed the blades to go forward a good 10 degrees ahead of the rotation plane. I wanted to see if the rotating blades at high rpm would form a cone with its apex toward the rear and the cone base forward of the hub attachment to the motor shaft due to the forward thrust of the blades.

The observed results are that the centrifugal force of the blades is so much stronger than the thrust that the blades are not forming an observable cone. The blades are turning in a pretty well flat plane and not forming an observable cone.

Conclusion _ _ _ a prop blade would fly out along the rotation plane BUT . . . . there is a "but" . . . . . considering that the mass of the blade had a forward thrust as it is detached it becomes unpredictable what trajectory it would take . . . . . considering also the speed at which the center of gravity of the detached mass would be moving, it becomes a very dangerous projectile.

Consider a small prop of 10 inches diameter and and the blade CG estimated at 4 inches from the rotation axis and assume a 12,000 rpm.
The CG (mass) of that blade would be travelling at 285.6 mph.
Much too fast for me to get out of the way if it is coming toward me .

Ya _ _ _ I will be in front of the prop only to start the engine at low rpm and move behind the plane of rotation for any higher rpm tests and will never run an engine in the pit areas.

Anyone can contradict on the basis that the risks are small but it is so easy to avoid another risk in our lives.

Zor
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Old Aug 02, 2013, 01:06 AM
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Ben D Wing's Avatar
The Peak District
Joined Dec 2006
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At least if you are hit by a breaking prop its your own doing so no one else is to blame. You are far more at risk in life from those imbeciles that insist on operating their mobile phones whilst driving. When caught they ought to be flogged!
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Old Aug 02, 2013, 11:17 AM
team sleprock
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United States, WA, Port Angeles
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I see more cops in my town talking on cell phones then peeps!
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Old Sep 29, 2013, 07:40 PM
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Nampa, ID
Joined Oct 2009
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Is anyone using the Evolution 20GX in this plane?
http://www.horizonhobby.com/products...ngine-EVOE20GX

Just wondering how it compares to the DLE.
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Old Oct 13, 2013, 02:00 AM
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Nampa, ID
Joined Oct 2009
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Hi guys

Those of you running the DLE 20, is there enough prop clearance for a 17x6?
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Old Oct 13, 2013, 10:14 AM
team sleprock
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United States, WA, Port Angeles
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yes
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Old Oct 13, 2013, 02:22 PM
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If I had one of these, I wouldn't waste time in church either, I'd be flying it.
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Old Oct 15, 2013, 12:44 PM
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Nampa, ID
Joined Oct 2009
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What spinner are you guys using?

Anyone with a DLE 20 running a tru turn spinner with a Xoar 17x6. Just wondering if I need a special cut. I have a message into try turn but haven't heard back yet.

I was looking at the H9 P51 spinner but I am not sure it can be adapted to the DLE20?
http://www.hangar-9.com/Products/Def...rodID=HAN99003


Update**
After looking around some more I see that the H9 spinner uses a standard 10-32 bolt. So maybe I can just get an adapter for it.
http://www.truturn.com/cgi-bin/store...4a&ppinc=adapt

But I guess the question is would the Xoar prop fit in the H9 spinner?
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Old Oct 15, 2013, 05:35 PM
team sleprock
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United States, WA, Port Angeles
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I am pretty sure mine did, I used the stock spinner, ( white ) that came with plane, with my xoar 17x6 prop!
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Old Oct 17, 2013, 11:43 PM
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Nampa, ID
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Just a few picts of how I mounted my DLE 20RA on my Eagle. I broke in the motor today and should have it back on the plane soon. I am waiting for one more servo to show up and then I can maiden this thing!
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Old Oct 18, 2013, 12:19 AM
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United States, WA, Port Angeles
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as someone pointed out too me, you should consider putting some x bracing in that open area on top the motor box!

just saying!

I see you hav some corner stock, but some more on top would help a lot!
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Old Oct 18, 2013, 08:59 AM
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Nampa, ID
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Good idea. I was thinking about boxing it in and pinning the firewall.
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Old Oct 18, 2013, 10:31 AM
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Joined Jun 2011
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I pinned my firewall and cut a piece of 1/8th ply to fit the top and the cut out all but about 3/4 inch which left the top open but really stiffened it up
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Old Apr 26, 2014, 03:27 AM
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United Kingdom, England, Manchester
Joined Apr 2014
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Hiya lads and ladies I got my h9 eagle yesterday I opened the box and the pilots head has broke off I must say excellent service from HH they are sending me a new canopy so thanks HH. I'm putting a saito 125 in with 5 savox servos and frsky receiver I'm thinking about a on board glow igniter any ideas anyone ? Its my first bipe and can't wait to fly it she looks stunning! The engine will be with me next Saturday so then the building will start. Does anybody now what flight time I'll get with this set up it will we flown at lower speeds (for now)
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