RE: DL-50 engine

RE: DL-50 engine
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RE: DL-50 engine - 7/19/2008 9:14:25 AM

Super08

Posts: 328
Joined: 12/17/2007
From: Fort McMurray, AB, CANADA
Status: offline

PSP makes a good one. Any drill guide made for a DA 50 will work.

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Post #: 2151

RE: DL-50 engine - 7/19/2008 11:19:47 AM

Bob Pastorello

Posts: 5214
Joined: 2/23/2002
From: El Reno, OK, USA
Status: offline

Same as DA 50 jig. Available from all sorts of places. I like the one from PSP Products.

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Post #: 2152

RE: DL-50 engine - 7/19/2008 12:08:49 PM

lill will

Posts: 393
Joined: 5/20/2007
From: prince frederick, MD, USA
Status: offline

I hopw this isn't a dumb question but what is prop noise?

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Post #: 2153

RE: DL-50 engine - 7/19/2008 12:23:21 PM

Bob Pastorello

Posts: 5214
Joined: 2/23/2002
From: El Reno, OK, USA
Status: offline

Rotational velocity at the tips, usually. Depends on prop design, tip shape, thickness, rigidity of blade, etc. Chart of tip speeds on my website, link from main page. As velocity approaches .7 mach (very easy on 23" + props these days) the prop begins turning so fast that the blades' tips remain in turbulent air which begins a process called "cavitation". Cavitation of a prop means it is no longer "pulling" against the air, but just spinning. This creates a bizarre and very loud noise, usually, that some call "ripping".

"Ripping" is actually when a prop is nearly fully-cavitated at the tips because the rpms are such that the tips actually go supersonic, exceeding mach 1 velocity.

Generally, it is not recommended.

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Bob Pastorello www.rcaerobats.net
Learn from others...you can't live long enough to make all the mistakes yourself....

(in reply to lill will)

Post #: 2154

RE: DL-50 engine - 7/19/2008 3:31:19 PM

Super08

Posts: 328
Joined: 12/17/2007
From: Fort McMurray, AB, CANADA
Status: offline

But it sounds really cool

Here is a link to a video. About a quarter the way into the movie he does some high speed passes and you can hear the prop ripping.

http://www.youtube.com/watch?v=aAH8BDr33ys

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If I buy one more engine it''s going to hurt more than my wallet if my wife gets ahold of it.......

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Post #: 2155

RE: DL-50 engine - 7/19/2008 4:38:39 PM

denney47

Posts: 182
Joined: 3/27/2004
From: Graham, WA, USA
Status: offline

quote:

ORIGINAL: ftimburgia

Does anyone make a prop jig for drilling the props for the DL 50.

The drill guide for the DL are the same as a DA, we normally have them in stock but are sold out, we do have engines in stock 50cc only. We will have drill guides back in stock in about two weeks.
Tom
Valley View RC

(in reply to ftimburgia)

Post #: 2156

RE: DL-50 engine - 7/19/2008 6:02:00 PM

BTerry

Posts: 862
Joined: 4/24/2002
From: Silverdale, WA, USA
Status: offline

quote:

ORIGINAL: Bob Pastorello

the tips actually go supersonic, exceeding mach 1 velocity.

Generally, it is not recommended.

To quote myself, "RIPPING means the tips have entered the TRANSONIC regime, not that they are supersonic. The air also doesn't travel exclusively in a chordwise flow, but also travels spirally outward from the hub to the tip (slightly). The tips of a 28" prop will actually go SUPERSONIC around 8000 rpm.

Beyond this point the propellor airfoil decreases in efficiency by increasing the occurrence of vortical "shedding" at the tip and wake and also the flow separates from the high-pressure surface, causing the shearing of air along the span of the blade, which increases the noise of the prop.

The "P-Tip" and scimitar props attempt to decrease these factors and result in some noise reduction if designed correctly.

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Post #: 2157

RE: DL-50 engine - 7/19/2008 11:56:48 PM

bigbuster

Posts: 119
Joined: 7/15/2002
From: AE, USA
Status: offline

I have had my Dl for quite some time about 8 months and never ran it. I fired it up today and ran about 3 tanks or 80 minutes through it, it ran great but vibrates
alot. Is the vibration normal and will it get better? Isure hope so because I have been giving my buddy a hard time with his DA. I am going to run it again tomorrow
and finish the 2 hours then I will tweek it. I am running the lawnboy 32:1 and a menz 22x8 prop. I am getting 7400 so I richened it back to about 6K. The 22x8 menz
doesn't seem to be enough load so I will put a 23x8 on her after I finish the 2 hours. If I can get rid of the vibration this will be one sweet puppy.

Jeff

(in reply to Pistolera)

Post #: 2158

RE: DL-50 engine - 7/20/2008 3:31:40 AM

Uncas

Posts: 441
Joined: 9/2/2003
From: St. Peters, MO,
Status: offline

What is that prop noise when you are hovering and you start sliding down? We all call that ripping because of the sound it makes.

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Post #: 2159

RE: DL-50 engine - 7/20/2008 3:32:53 AM

craigteffe

Posts: 456
Joined: 2/7/2003
From: Maryville, TN, USA
Status: offline

Gas engines tend to vibrate more than most engines. Make sure you ballance your prop, not just the blades but the hub also.

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Post #: 2160

RE: DL-50 engine - 7/20/2008 1:09:39 PM

chuck l

Posts: 901
Joined: 11/21/2002
From: Stacy, MN, USA
Status: offline

quote:

ORIGINAL: bigbuster

I have had my Dl for quite some time about 8 months and never ran it. I fired it up today and ran about 3 tanks or 80 minutes through it, it ran great but vibrates
alot. Is the vibration normal and will it get better? Isure hope so because I have been giving my buddy a hard time with his DA. I am going to run it again tomorrow
and finish the 2 hours then I will tweek it. I am running the lawnboy 32:1 and a menz 22x8 prop. I am getting 7400 so I richened it back to about 6K. The 22x8 menz
doesn't seem to be enough load so I will put a 23x8 on her after I finish the 2 hours. If I can get rid of the vibration this will be one sweet puppy.

Jeff

It is a big no no to run the engine rich as much as you are doing, it will carbon up the plug and ring will fast. Tune the high speed needle back to where it was and keep the rpm down for a few tank fulls.

(in reply to bigbuster)

Post #: 2161

RE: DL-50 engine - 7/20/2008 1:14:01 PM

Bob Pastorello

Posts: 5214
Joined: 2/23/2002
From: El Reno, OK, USA
Status: offline

AND - proper leaning of needles can address a LOT of vibration. Mine thumped like a Harley until I leaned the low end. Both the 50 and the 100 seem to like "leaner" needles on the low end than one would think.

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Bob Pastorello www.rcaerobats.net
Learn from others...you can't live long enough to make all the mistakes yourself....

(in reply to chuck l)

Post #: 2162

RE: DL-50 engine - 7/20/2008 2:53:01 PM

lil-redrex

Posts: 46
Joined: 8/30/2005
From: WestAust, AUSTRALIA
Status: offline

quote:

ORIGINAL: nonstoprc

quote:

ORIGINAL: georgee

I"ve also received this beauty last week from Dlusa.I hope it will be fit to my Composite Extra 2x2.

Georgee

This is an interesting combo. Please let us know how it goes.

Ive got one (DL) setup in the Comp-Arf 2.12 (new version of the 2x2, has slightly more wing area, bigger throws and can tunnel) with an MTW75 can, very good combo and out of site performace. Use it for IMAC. Good combo

(in reply to nonstoprc)

Post #: 2163

RE: DL-50 engine - 7/20/2008 3:43:17 PM