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All Forums >> RC Airplanes >> Pylon Universe - RC Pylon Racing >> Q-500 Racing >> RE: Future of Composites
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RE: Future of Composites - 6/20/2004 5:09:14 PM   
HighPlains


 

Posts: 2670
Joined: 3/2/2003
From: Over da rainbow, KS, USA
Status: offline 		Stan & Gary,

On the straight line swept forward wings, the first one was just a slightly damaged wing that was just cut at the center section and reglued with the sweep. On all the later wings, Gary is correct, I moved the template mounting position on by bed of nails so the cores were a parallelogram.. This kept the same airfoil. Stan is correct with his math on the prototype, if you cut a wedge out the chord is increased.

BTW, all of my wings have about 10 1/8” chord with the 52” span. I have never thought that it made them any slower with the extra area – about 515 - 517 squares. I use an quarter ellipse for the platform of the tip. They are 2 inches wide and 10 inches long. The area of an ellipse is (Pi x major axis x minor axis) so {3.14 x 10.125 x 2}/4 gives the area of each tip.

On the Havoc, the area is slightly higher due to the extra length of the swept back wing section and the chord is still around 10 1/8 inches. I offset my templates by 4” when I cut the panels, then cut the 24 inch panels into 4 sets. Then I reversed the offset to cut the opposite side’s panels. Like I said, about twice as much work to build.

bob

(in reply to Freeman Jr.)
       Post #: 101

RE: Future of Composites - 6/20/2004 6:08:52 PM   
leeul


 

Posts: 61
Joined: 8/15/2002
From: Goodyear, AZ, USA
Status: offline 		"and yes Lee was using a wood Q500 and going very fast. Good job Lee. Lee what were your other times at Phoenix??"

My best time in phx is a 1:07 with the old NEME Q and the best with the Force was at the NATS last year a 1:08. most of my Q500 times are 11 lap times.

(in reply to Freeman Jr.)
       Post #: 102

RE: Future of Composites - 6/20/2004 6:15:59 PM   
Freeman Jr.


 

Posts: 84
Joined: 4/11/2002
From: Donny , FL, USA
Status: offline 		What was your backup time at the race you went 104?

(in reply to leeul)
       Post #: 103

RE: Future of Composites - 6/20/2004 6:27:22 PM   
leeul


 

Posts: 61
Joined: 8/15/2002
From: Goodyear, AZ, USA
Status: offline 		A 1:06 with 2 cuts and 1:12 clean. That is why I am sure the 1:04 is most likely A 9 lap time. But like when Travis set the Best time I wasn’t going to complain.

Lee

(in reply to Freeman Jr.)
       Post #: 104

RE: Future of Composites - 6/20/2004 7:14:31 PM   
Stand



Posts: 94
Joined: 1/1/2003
From: Austin, TX, USA
Status: offline
quote:

The templates required to cut the swept section would need to be set at an angle relative to the hot wire and be designed so that the resultant chord is 10" relative to the centerline.


Gary the above was kind of sort of my description of your "parallelogram" planform . I had a lot of fun digging up some high school skills to do the trig -- been a looong time. At first I couldn't get the sin function to work using one of my old engineering text books from 1963, but then I went to help in Excel and remembered that you need to convert to radians. It took me about two hours to do a 1 minute problem.

Then I just used Excel to do all the work, no need to learn trigonometry any more; just ask Bill Gates.

Stan

(in reply to HighPlains)
       Post #: 105

RE: Future of Composites - 6/21/2004 11:49:05 AM   
luv to race


 

Posts: 466
Joined: 12/10/2002
From: Liquored, FL,
Status: offline 		Great discussion guys! Bob's plane looks pretty cool and I'm sure it's fast. I have first hand experience on having Bob's plane blow right by me.

So are we saying that Travis's record breaking time was a 9 lap time? I think he went 1:03:32 ... When I broke Chip's record with a 1:03:98, my backup time was a low 1:04 (:15?)... We should have a backup rule put in place.

(in reply to Stand)
       Post #: 106

RE: Future of Composites - 6/22/2004 5:08:21 PM   
js3



Posts: 1142
Joined: 1/30/2002
From: Arvada, CO, USA
Status: offline 		Bob,

When referring to the fuse sides and the 'magical' seven degree angle for the NACA duct shape, from where is the seven degrees measured? Is it seven degrees from the datum/center/thrust line or seven degrees from the angle of the fuse side in front of the wing's trailing edge? I'm not sure that I'm wording this question clearly. If so, let me know and I'll try to rephrase.

_____________________________

John
I feel a lot more like I do now than I did earlier!

(in reply to luv to race)
       Post #: 107

RE: Future of Composites - 6/22/2004 7:54:09 PM   
HighPlains


 

Posts: 2670
Joined: 3/2/2003
From: Over da rainbow, KS, USA
Status: offline 		John,

I’m measuring the 7 degrees from the datum/center line side view of the fuselage.. The NACA duct shape is the shape of the fuselage as viewed from above. In essence, the shape of the duct is backwards to the normal orientation that you see it on cars and airplanes when it is used as an air inlet. I know it is hard to find the coordinates for the duct, I did a small search on the Internet without finding it. I had it in a 15 year old copy of Sport Aviation (EAA magazine) with the coordinates. So here are the numbers I used on the Havoc fuselage. The first set of numbers are from 0 to 1.0 just to reference where you are at. The second column of numbers is inches from the trailing edge of the wing, the third column is the distance from the center line (1/2 of the total width at that point), and the fourth column is the (½ width) in 1/32” of an inch, and the 5th column is just the full width of the fuselage in 32nds of an inch.

(1) <2> (3) <4> (5)

(0) <0> (1.44) <46> (92)
(.1 <1.53> (1.43) <45.8> (91.5)
(.2) <3.05> (1.31) <41.9> (83.8)
(.3) <4.58> (1.04) <33.3> (66.6)
(.4) <6.1> (.883) <28.3> (56.5)
(.5) <7.63> (.67) <21.4> (42.9)
(.6) <9.15> (.56) <17.9> (35.8)
(.7) <10.68> (.451) <14.4> (28.9)
(.8) <12.2> (.34) <10.9> (21.8)
(.9) <13.73> (.23) <7.4> (14.7)
(1.0) <15.25> (.12) <3.9> (7.8)

Plot these numbers out by drawing a center line from the wing’s trailing edge back, then at each measurement of column two is a distance back, measure left and right of the line by the amount of column 3, then connect the dots. Now you have the plan form of the pressure recovery shape. If you want a longer fuselage, then take your length in inches and divide by 15.25. Then multiply the numbers in column 2 by that number and plot the new numbers. Also note, that the width of the fuselage is ¼ inch where I stopped plotting. I added a stinger on the back of the fuselage and sanded it to a point, and that adds another inch or two behind the V-tail.

Bob
Sorry for the lack of clean columns - just follow the sets of ( ) or < >

(in reply to js3)
       Post #: 108

RE: Future of Composites - 7/5/2004 3:51:48 PM   
HighPlains


 

Posts: 2670
Joined: 3/2/2003
From: Over da rainbow, KS, USA
Status: offline 		OK, I have shared a few design features that I think will make a fast Quickie (besides a smoken' engine) But I have been holding out till now... Check out this web site for some design ideasfor your next ship. Extreme speed fliers, this is especially for you - Bob

http://www.xenophilia.com/zb/zb0015/pat.htm

(in reply to HighPlains)
       Post #: 109

RE: Future of Composites - 7/26/2004 3:41:32 AM   
js3



Posts: 1142
Joined: 1/30/2002
From: Arvada, CO, USA
Status: offline 		Just bumping this thread back to the top.

_____________________________

John
I feel a lot more like I do now than I did earlier!

(in reply to HighPlains)
       Post #: 110

RE: Future of Composites - 8/3/2004 5:14:02 AM   
P. Johnson


 

Posts: 177
Joined: 7/24/2004
From: Paris, IL, USA
Status: offline 		I have layed out of racing for about 6 years now. I am going to come back and race Q-500 next year and will probably do what i have always done. I by what i can afford(whats on sale)either a lost "scat cat", or a Dodger or something similar to it. NO i Won't be as fast as some of the people who are buying the all composite airplanes and the latest and greatest updated engines. BUT i WILL spend several weekends doing nothing but flying the course and practicing a concistant pattern, NO I will not be able to beat the best....but i WILL still be competative with most for a lot less money. So order all the composites you want and see if it really makes you a better pilot and a TRUE HOBBIEST. Isn't this what this is supposed to be...a HOBBY?
just my opinion

(in reply to daven)
       Post #: 111

RE: Future of Composites - 8/3/2004 4:08:18 PM   
js3



Posts: 1142
Joined: 1/30/2002
From: Arvada, CO, USA
Status: offline
quote:

Isn't this what this is supposed to be...a HOBBY?


Yep. It's a hobby all right. For me anyway.

_____________________________

John
I feel a lot more like I do now than I did earlier!

(in reply to P. Johnson)
       Post #: 112

RE: Future of Composites - 8/3/2004 5:03:56 PM   
Ed Smith


 

Posts: 2837
Joined: 12/29/2001
From: Brantford, ON, CANADA
Status: offline
quote:

Isn't this what this is supposed to be...a HOBBY?


Peter, you are correct, Until that is, you get beaten in a heat by a couple of seconds! Then it gets serious. "Gee, if only I had made that wing one ounce lighter..etc...etc...etc."

Ed S

(in reply to js3)
       Post #: 113

RE: Future of Composites - 8/3/2004 6:28:09 PM   
PylonWorld



Posts: 1346
Joined: 12/29/2001
From: Monroe, NC, USA
Status: offline 		For some of us, building is as much of the hobby as flying is. Perhaps even more.

Building composites is just another way of building planes. But composites can be much more consistent than other ways of building. I get more enjoyment out of flying planes that are nearly identical to the ones that I crash or wear out.

When I got back into R/C in 2000 and got the racing bug again, I found the Kangke F3D/30. It has a 402 square inch wing (as opposed to the 463 reported in their materials). It is essentially the same size as a Q-40 and is all molded composite. For my first one, I mounted a Tower .46 in it. It was really fast and it grooved pretty well. I made the mistake of flying on a grass runway that was not freshly cut and caught a wingtip. It busted up the nose. The nice thing was that the retail price is less than $160 and I could get another one just like the one I broke. So I got another one instead of trying to fix the first one. I added fiberglass tape to the seams on the inside of the fuselage on a Friday night. At 10 am on Saturday morning I started putting it together. At 4 pm I started the engine. If there had been enough daylight left I could have flown it. I used the same model settings in the radio with one small adjustment to the throttle. I flew it on Sunday and it flew just like the first one. I flew several of these and each one flew just like the previous ones.

This spoiled me and I decided that before I got serious about competition that I was going to get serious about being able to build my own all molded composite planes. So I started learning about composite construction and started my own projects. Those projects are nearing completion and soon I will have complete sets of molds for a Q-500 and two Q-40's.

Molded composite construction is not rocket science. It does take some time and experimentation to learn, but once you learn it, the whole process becomes very comfortable. And being able to build a complete airplane in a week is very gratifying.

_____________________________

Don Stegall
RCPRO Chairman of the Board

(in reply to Ed Smith)
       Post #: 114

RE: Future of Composites - 8/6/2004 1:01:17 AM