RE: 8.8X9.75 @ 19,300+ !  
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RE: 8.8X9.75 @ 19,300+ ! - 5/13/2008 12:03:24 AM   
freakingfast


 

Posts: 698
Joined: 1/3/2005
From: mather, CA, USA
Status: offline 		That leading edge came with the "clipped wing" version Diamond Dust. I hunted it down and it turns out to be 1/8 doll house roof cap. Hold off till I test fly her and I'll let you know if it spoils the air flow (stalls) in hard turns. I’ve been sick today and there is very turbulent wind here today so tomorrow looks good for flight. Going to test run the engine on the plane and rattle the neighbors a bit now.

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RE: 8.8X9.75 @ 19,300+ ! - 5/13/2008 12:57:54 AM   
freakingfast


 

Posts: 698
Joined: 1/3/2005
From: mather, CA, USA
Status: offline 		Glad I tested it. The throttle servo was reversed (dummy), wouldn’t start, the plug finally died, the prop wasn’t oriented horizontal. Got a blister, the coupling that I hold it by is too short. The needle needed to be opened another ½ turn (a tad rich, off peak) for a total of two turns out, I guess the bubble-less clunk adds a bit of restriction but the needle still has a nice definite peak. I held it lightly several ways and saw no bubbles with a ¼ tank, so far- so good, at least on the ground.

Dang that thing pulls hard, so temped to let it go. Soon!

< Message edited by freakingfast -- 5/13/2008 1:02:01 AM >

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When in doubt, give it full power. The smaller
pieces fit easier in the bag! Revver Bro #201

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       Post #: 52

RE: 8.8X9.75 @ 19,300+ ! - 5/14/2008 1:36:59 AM   
Mike Connor



Posts: 1337
Joined: 1/10/2002
From: Tulsa, OK, USA
Status: offline
quote:

ORIGINAL: freakingfast

That leading edge came with the "clipped wing" version Diamond Dust. I hunted it down and it turns out to be 1/8 doll house roof cap. Hold off till I test fly her and I'll let you know if it spoils the air flow (stalls) in hard turns.

Deltas fly by there own set of rules. My experience says the sharp leading edge will not have a negative effect.


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Mike
http://www.mikesrc.us/

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       Post #: 53

RE: 8.8X9.75 @ 19,300+ ! - 5/14/2008 1:39:01 AM   
freakingfast


 

Posts: 698
Joined: 1/3/2005
From: mather, CA, USA
Status: offline
quote:

ORIGINAL: Mike Connor


quote:

ORIGINAL: freakingfast


Deltas fly by there own set of rules. My experience says the sharp leading edge will not have a negative effect.



You are so right!


_____________________________

When in doubt, give it full power. The smaller
pieces fit easier in the bag! Revver Bro #201

(in reply to Mike Connor)
       Post #: 54

RE: 8.8X9.75 @ 19,300+ ! - 5/14/2008 1:41:43 AM   
freakingfast


 

Posts: 698
Joined: 1/3/2005
From: mather, CA, USA
Status: offline 		Success!

That thing is fastest thing I’ve flown. Eyeball speed looked to be about 190+ and I think there’s more to be found. It was realy gusty, so much so that I had to hold the plane down on the work table so it wouldn’t blow away. I launched at a lower angle than normal so it won’t end up right over my head. It was a bit twitchy on the roll axis at takeoff so I’ll reduce my rates and remove the all the expo that I use for launch. Trim was close, two clicks up and one right. I set the timer at 2 minutes 45 seconds which was perfect for an 8 oz. tank, which left about enough fuel left for one landing go around. The smoke trail was nice and constant and the engine ran flawlessly. I pulled the plug and the element was still shinny, centered and even. The clipped wing DD flew better than I had hoped, smooth high speed low passes, and predicable turns. I tried some abrupt turns and “walls” and not a hint of high speed stall.
My biggest surprise was the roll rate, faster than the standard DD and about twice that of the Outlaw! What a buzz saw! The landing was perfect, with the strong head wind it ran on the landing skids only about 10 feet. I few it once, the only other pilot left, my cap blew off my head and I had to chase my fuel jug so I thought to myself this is nuts, I’m going home in one piece.
The prop may be too much; it didn’t unload much, maybe 1 K or so. I was a bit busy at the time to realy listen. It was probably running about 22.5K at best and I’d like to see it at about 24 in flight. Next time out I may want to try a 8.8 X 9.5 and maybe a 8.8 X 9.25.

A very good day!


_____________________________

When in doubt, give it full power. The smaller
pieces fit easier in the bag! Revver Bro #201

(in reply to freakingfast)
       Post #: 55

RE: 8.8X9.75 @ 19,300+ ! - 5/14/2008 3:07:54 AM   
Mike Connor



Posts: 1337
Joined: 1/10/2002
From: Tulsa, OK, USA
Status: offline 		Congratulations on the maiden. Seems you could cut down the landing skids by 50% or more. They have to be a lot of drag. Doppler should prove very interesting when you get everything right.

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Mike
http://www.mikesrc.us/

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RE: 8.8X9.75 @ 19,300+ ! - 5/14/2008 4:43:56 AM   
freakingfast


 

Posts: 698
Joined: 1/3/2005
From: mather, CA, USA
Status: offline
quote:

ORIGINAL: Mike Connor

Congratulations on the maiden. Seems you could cut down the landing skids by 50% or more. They have to be a lot of drag. Doppler should prove very interesting when you get everything right.

Yes they do have lot of drag. The rear ones are held in place with set screws and the front is attached to the motor mount if I ever find a nice grass field to land on I'll take them off.

I just got back home and got another flight in. The wind was gone The good news is I got it on video, the club president had his camera and he said he would post it soon on YouTube. Ill let you know the link later. The bad news is, it high speed stalled and it realy shook me up which lead to my worst landing ever with a delta (400+ flights) all caught in living color.
The engine linkage had slipped a bit and I could not shut the engine off right away, I was about to abort than the darned thing quit so I landed hot slid off the end of the runway and the thick weeds snagged and spun it. The only damage was some stress marks near the tip of the prop so that prop is toast.

It took a dive and a quick full pull to make it happen and I may have not pulled the stick strait back. It was the most violet event I have ever witnessed. It totally lost all laminar air flow. Everyone thought I did it on purpose (because of my Outlaw flying style). The Diamond Dust does not recover like an Outlaw. I barely got the DD out of a wobbly flat spin, very mushy, slow to recover. I will test this again much higher and further out.

I did this once to a Whiplash and no matter what I did, it was locked in a flat spin to the ground.

Still a good day!


< Message edited by freakingfast -- 5/14/2008 4:50:10 AM >

_____________________________

When in doubt, give it full power. The smaller
pieces fit easier in the bag! Revver Bro #201

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       Post #: 57

RE: 8.8X9.75 @ 19,300+ ! - 5/14/2008 7:08:08 AM   
combatpigg



Posts: 9236
Joined: 11/22/2003
From: arlington, WA, USA
Status: offline 		Congratulations! Sounds like your report card for being ready is way up there. This kind of duty has to be a walk in the park for that engine compared with being inside a DF torture chamber.

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RE: 8.8X9.75 @ 19,300+ ! - 5/15/2008 12:14:48 AM   
freakingfast


 

Posts: 698
Joined: 1/3/2005
From: mather, CA, USA
Status: offline 		Here's the video link. I don't know if any Doppler info can be had from it, I noticed that the same guy that asked the same question twice "is there a pump in that" when I was on final had his car radio blaring in the background. It looks like Richard edited out the first few minutes because of it was out of focus. Note the reason why you don’t land in the grass around here.

http://www.youtube.com/watch?v=fVp39wJMeCM

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When in doubt, give it full power. The smaller
pieces fit easier in the bag! Revver Bro #201

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       Post #: 59

RE: 8.8X9.75 @ 19,300+ ! - 5/15/2008 1:01:26 AM   
Mike Connor



Posts: 1337
Joined: 1/10/2002
From: Tulsa, OK, USA
Status: offline 		The only pass that gave decent Doppler info was at the 20 second mark (down wind/no wind?). There may have been better passes and better flights but here is what I got.
158 mph
20,700 rpm
I like my Doppler readings to be backed up by other speed measuring methods but this is what we have for now. Not too bad considering everything.

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Mike
http://www.mikesrc.us/

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RE: 8.8X9.75 @ 19,300+ ! - 5/15/2008 1:11:31 AM   
freakingfast


 

Posts: 698
Joined: 1/3/2005
From: mather, CA, USA
Status: offline 		That's great info Mike! Thanks a million
I did'nt think it unloaded much, I will be dropping down on pitch. The engine's peak hp is at 23K and I'd like to put it at or a little over that.

Thanks for the quick info Mike!

_____________________________

When in doubt, give it full power. The smaller
pieces fit easier in the bag! Revver Bro #201

(in reply to Mike Connor)
       Post #: 61

RE: 8.8X9.75 @ 19,300+ ! - 5/15/2008 1:39:28 AM   
Mike Connor



Posts: 1337
Joined: 1/10/2002
From: Tulsa, OK, USA
Status: offline 		The right prop with a good tune and no skids and that thing will cook. Nice job.

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RE: 8.8X9.75 @ 19,300+ ! - 5/15/2008 2:46:52 AM   
freakingfast


 

Posts: 698
Joined: 1/3/2005
From: mather, CA, USA
Status: offline 		I can shorten the skids by half and perhaps teardrop shape whats left. If I loose them, there will be one fast flight followed by repair time .
Options. #1 change prop. #2 shorten header 7/16" for peak at 24K but this means cutting closer to both the bend on the header AND the taper on the pipe.
#4 try a nitro tuned pipe #3 up the nitro from 30% to 60%. The down side for this is A: shim the head. B: less glow plug life C: less engine life D: less run time. E: fuel cost.

_____________________________

When in doubt, give it full power. The smaller
pieces fit easier in the bag! Revver Bro #201

(in reply to Mike Connor)
       Post #: 63

RE: 8.8X9.75 @ 19,300+ ! - 5/15/2008 4:18:38 AM   
combatpigg



Posts: 9236
Joined: 11/22/2003
From: arlington, WA, USA
Status: offline 		FF, the difference in actual speed won't be that much if you go nuts with the nitro. My first instinct with props is to whittle on the prop that you want to see work until you see the plane slow down, then move on to plan B prop, etc. I haven't seen any world class speed props in person, but get the impression that the blades are thinner than stock APC carbon jobs.

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Led Zeppelin is NOT "old fogie" music.

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       Post #: 64

RE: 8.8X9.75 @ 19,300+ ! - 5/15/2008 2:40:00 PM   
bob27s



Posts: 4624
Joined: 4/9/2002
From: Cleveland, OH, USA
Status: online 		just change one thing at a time..... or you will never understand how the change affects performance.

The 8.8x9.75 prop has not demonstrated very good speed in the air for the Q-500 aircraft. Try the 8.8x9 and 8.8x9.25 props. Do not be that concerned with the ground rpm ... leave the pipe at the same length to start with.

The project looks great.... im pleased to hear it is performing well !


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Bob Brassell
Jett Engineering - Engine Mfg Support Forum Host

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